Formulations for nonaqueous fluid additives

Abstract

In embodiments, a drilling additive formulation of a fatty acid composition and biodiesel provides additive benefits in drilling fluids. The fatty acid composition may provide immediate performance improvement to the drilling fluid having the drilling additive formulation therein. The benefits include one or more of fluid loss control, emulsification, wetting, dilution, or pour point depression. The biodiesel provide may provide immediate dilution, pour point depression, of the fatty acid composition and may convert to fatty acids in in situ to provide further performance benefits to the drilling fluid. The fatty acid compositions include various fatty acids, maleated fatty acids, or fatty acids having elevated acid numbers. The biodiesel within the drilling additive formulations include various forms of biodiesel including scientifically defined biodiesel, fatty acid methyl esters, biodiesel with an elevated acid number, or "off-spec" biodiesel. Methods of making and using the drilling additive formulations are disclosed.

Description

Attorney Docket No. IS24.1206-WOFORMULATIONS FOR NONAQUEOUS FLUID ADDITIVESCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to U. S. Provisional Patent Application Serial No. 63 / 762,960, filed on 25 February 2025, the disclosure of which is incorporated herein, in its entirety.BACKGROUND

[0002] Wellbore operations include drilling a borehole in a formation to access reservoirs of hydrocarbons and other subsurface resources. During drilling of the borehole, various fluids may be circulated into the borehole through a drill pipe and drill bit and may subsequently flow upward through the borehole to the surface. For example, a drilling fluid (e.g., an aqueous based fluid or an oil-based fluid) may be pumped down the inside of the drill pipe, through the drill bit, and into the borehole or wellbore. The drilling fluid returns to the surface through the annulus. The drilling fluid may lubricate and cool the drill bit, facilitate transport of formation cuttings to the surface, prevent formation of blowouts by maintaining a hydrostatic pressure greater on the formation than the formation pressure, maintain well stability, and reduce fluid loss to the formation.

[0003] Drilling fluids may be water-based (aqueous-based), or may be nonaqueous, such as oil based or synthetic-based. In nonaqueous drilling fluids, water is the discontinuous (dispersed) phase and oil (or a synthetic material) is the continuous phase. Non aqueous drilling fluids may be more compatible with water-sensitive formations, such as watersensitive clays, than aqueous drilling fluids. In addition, nonaqueous drilling fluids may not substantially cause shale instability to the formation as may be more common with aqueous drilling fluids.

[0004] Nonaqueous drilling fluids may be stabilized with a wetting agent formulated and configured to provide an oil-wet surface to drilling solids and particles in the drilling fluid to reduce or prevent agglomeration and the particles from settling in the drilling fluid. One problem associated with wetting agents is the delivery of the wetting agents into the drilling fluid. For example, many wetting agents have a high melting temperature and are solids at ambient conditions proximate a borehole, making it difficult to mix the wetting agents intoAttorney Docket No. IS24.1206-WOthe drilling fluid. Wetting agents are conventionally provided to a drilling fluid as a composition that includes a solvent such as a base oil, and a pour point depressant to facilitate flow of the wetting agent to the drilling fluid.BRIEF SUMMARY

[0005] This disclosure describes fluid additive formulations of nonaqueous fluids for oil and gas applications.

[0006] In an embodiment, a drilling additive formulation of nonaqueous fluids is disclosed. The drilling additive formulation includes a fatty acid composition and a biodiesel, wherein the biodiesel is less than 90 weight percent (wt %) of the drilling additive formulation.

[0007] In some embodiments, the biodiesel includes one or more of Cl 8 monounsaturated fatty acid methyl esters, polyunsaturated fatty acid methyl esters, C16 saturated methyl esters, or C18 saturated methyl esters. In some embodiments, the fatty acid composition includes at least one maleated fatty acid. In some embodiments, the maleated fatty acid includes maleated tall oil fatty acid. In some embodiments, the maleated fatty acid includes a hydrolyzed maleated fatty acid. In some embodiments, the maleated fatty acid is 90 wt % or less of the drilling additive formulation and the biodiesel is less than 50 wt % of the drilling additive formulation. In some embodiments, the drilling additive formulation includes less than 2 wt % water.

[0008] In some embodiments, the fatty acid composition includes at least one C8 to C20 saturated, monounsaturated, or polyunsaturated fatty acid and the biodiesel is less than 40 wt % of the drilling additive formulation. In some embodiments, the fatty acid composition includes one or more of oleic acid, linoleic acid, linolenic acid, or stearidonic acid. In some embodiments, the drilling additive formulation has a pour point of about -6 °C or less.

[0009] In some embodiments, the drilling additive composition includes a wax inhibitor. In some embodiments, the drilling additive composition includes an emulsifier. In some embodiments, the emulsifier includes at least one amidoamine. In some embodiments, the biodiesel is at least 35 wt % of the drilling additive formulation.

[0010] In some embodiments, the fatty acid composition includes one or more maleated fatty acids, wherein the one or more maleated fatty acids are about 10 wt% to aboutAttorney Docket No. IS24.1206-WOof the drilling additive formulation, and the drilling additive formulation further comprises at least one amidoamine resin, wherein the at least one amidoamine resin is about 25 wt % to about 55 wt % of the drilling additive formulation, and butoxytriglycol, wherein the butoxytriglycol is about 1 wt % to about 20 wt % of the drilling additive formulation. In some embodiments, the one or more maleated fatty acids are about 20 wt % to about 30 wt % of the drilling additive formulation, the at least one amidoamine resin is about 35 wt % to about 45 wt % of the drilling additive formulation, the biodiesel is about 20 wt % to 30 wt % of the drilling additive formulation, and the butoxytriglycol is about 10 wt % or less of the drilling additive formulation.

[0011] In an embodiment, a method of forming a drilling additive formulation is disclosed. The method includes providing a fatty acid composition, mixing a biodiesel with the fatty acid composition to form the drilling additive formulation, and wherein the biodiesel is less than 90 weight% of the drilling additive formulation.

[0012] In some embodiments, providing a fatty acid composition includes providing a maleated fatty acid. In some embodiments, the maleated fatty acid is 90 weight percent (wt %) or less of the drilling additive formulation and the biodiesel is less than 50 wt % of the drilling additive formulation. In some embodiments, the method includes hydrolyzing the maleated fatty acid effective to hydrolyze maleic anhydride moieties present in the maleated fatty acid. In some embodiments, hydrolyzing the maleated fatty acid includes adding water to the drilling additive formulation, wherein the water is less than about 2 wt % of the drilling additive formulation.

[0013] In some embodiments, the fatty acid composition includes at least one C8 to C20 saturated, monounsaturated, or polyunsaturated fatty acid and the drilling additive formulation has a pour point of about -6 °C or less. In some embodiments, the method includes mixing an emulsifier with the fatty acid composition and biodiesel, wherein the emulsifier includes at least one amidoamine. In some embodiments, the method includes mixing at least one glycol into the drilling additive formulation, the at least one glycol including one or more of butoxytri glycol or butoxy di glycol.

[0014] In some embodiments, the method includes mixing at least one amidoamine and butoxytriglycol into the drilling additive formulation, wherein the fatty acid composition includes one or more maleated fatty acids that are about 20 wt % to about 30 wt % of theAttorney Docket No. IS24.1206-WOdrilling additive formulation, the at least one amidoamine is about 35 wt % to about 45 wt % of the drilling additive formulation, the biodiesel is about 20 wt % to 30 wt % of the drilling additive formulation, and the butoxytriglycol is about 5 wt % to about 15 wt % of the drilling additive formulation.

[0015] In some embodiments, the at least one amidoamine may be used in place of the fatty acid composition.

[0016] In an embodiment, a method of forming a borehole extending through an earth formation is disclosed. The method includes mixing a drilling additive formulation with a drilling fluid, the drilling additive formulation including a fatty acid composition and a biodiesel. The method includes pumping the drilling fluid including the drilling additive formulation into the earth formation.

[0017] In some embodiments, mixing a drilling additive formulation with a drilling fluid includes mixing the drilling additive formulation including less than about 90 wt % of the biodiesel, with the drilling fluid.

[0018] In some embodiments, the fatty acid composition includes one or more maleated fatty acids, and the drilling additive formulation includes at least one amidoamine and at least one glycol. In some embodiments, the one or more maleated fatty acids are about 10 weight percent (wt %) to about 40 wt % of the drilling additive formulation, the at least one amidoamine is about 25 wt % to about 55 wt % of the drilling additive formulation, the biodiesel is about 10 wt % to 40 wt % of the drilling additive formulation, and the at last one glycol includes butoxytriglycol and the butoxytriglycol is about 1 wt % to about 20 wt % of the drilling additive formulation.

[0019] In some embodiments, the method includes mixing water with the drilling additive formulation, wherein the water is less than about 2 wt % of the drilling additive formulation.

[0020] In some embodiments, mixing a drilling additive formulation with a drilling fluid includes flowing the drilling additive formulation from a drum or a barrel into the drilling fluid.

[0021] In some embodiments, the method includes forming a borehole in the earth formation. In some embodiments, pumping the drilling fluid including the additive formulation into the earth formation includes forming a borehole in the earth formationAttorney Docket No. IS24.1206-WOwhile pumping the drilling fluid including the drilling additive formulation into the earth formation.

[0022] In some embodiments, the method includes forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid.

[0023] In some embodiments, a formulation of maleated fatty acid (biodiesel) as a fluid loss control additive is disclosed and includes low viscosity at ambient and low temperature and the ability to increase the weight percentage of a wetting agent for improved performance without excessive viscosity.

[0024] In some embodiments, the generation of a wetting agent, in situ, from a biodiesel component occurs to formulate nonaqueous fluid (NAF) additives. In some embodiments, biodiesel is used as an environmentally friendly solvent or active material for a NAF chemistry formulation. In some embodiments, the ability to increase performance up to 100% in a formulation of NAF is accomplished by counting biodiesel as an active component.

[0025] In some embodiments, a wetting agent comprises an elevated acid number of biodiesel, glycerin byproducts, or a combination thereof.

[0026] In some embodiments, a diluent for a wetting agent, emulsifier, or fluid loss additive comprises an elevated acid number of biodiesel, glycerin byproducts, or a combination thereof.

[0027] In some embodiments, biodiesel is used in combination with wax inhibitors to reduce pour points of NAF additive formulations.

[0028] In an embodiment, a drilling additive formulation for NAFs is disclosed. The drilling additive formulation includes a fatty acid composition including one or more maleated fatty acids, wherein the one or more maleated fatty acids are about 10 weight percent (wt %) to about 40 wt % of the drilling additive formulation. The drilling additive formulation includes at least one amidoamine, wherein the at least one amidoamine is about 25 wt% to about 55 wt% of the drilling additive formulation. The drilling additive formulation includes a biodiesel, wherein the biodiesel is about 10 wt % to 40 wt % of the drilling additive formulation. The drilling additive formulation includes butoxytriglycol, wherein the butoxytriglycol is about 1 wt % to about 20 wt % of the drilling additive formulation.Attorney Docket No. IS24.1206-WO

[0029] In some embodiments, the one or more maleated fatty acids are about 20 wt % to about 30 wt % of the drilling additive formulation, the at least one amidoamine is about 35 wt % to about 45 wt % of the drilling additive formulation, the biodiesel is about 20 wt % to 30 wt% of the drilling additive formulation, and butoxytriglycol is about 5 wt % to about 15 wt % of the drilling additive formulation.

[0030] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0031] Additional features and advantages of embodiments of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such embodiments. The features and advantages of such embodiments may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims or may be learned by the practice of such embodiments as set forth hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to describe the manner in which the above-recited and other features of the disclosure can be obtained, a more particular description will be rendered by reference to specific implementations thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the accompanying figure. While some of the drawings may be schematic or exaggerated representations of concepts, at least some of the drawings may be drawn to scale. Understanding that the drawings depict some example implementations, the implementations will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[0033] FIG. 1 is a schematic representation of a drilling system for drilling an earth formation to form a borehole defining a wellbore, according to at least some embodiments.

[0034] FIG. 2 is a graph of viscosity of maleated fatty acid in aqueous form at different concentrations.Attorney Docket No. IS24.1206-WO

[0035] FIG. 3 is a flow chart of a method of forming a drilling additive formulation, according to at least some embodiments.

[0036] FIG. 4 is a flow chart of a method of forming a borehole extending through an earth formation, according to at least some embodiments.

[0037] FIG. 5 depicts FTIR spectra of Tenax 2010, MTO 85, and Sterdrill 7010 prior to hydrolysis.

[0038] FIG. 6 is an FTIR spectra of Sterdrill 7010 before and after hydrolysis with water.

[0039] FIG. 7 depicts FTIR spectra of Tenax 2010, MTO85, and Sterdrill 7010 after hydrolysis with water.DETAILED DESCRIPTION

[0040] This disclosure describes fluid drilling additive formulations of nonaqueous fluids (NAF) for oil and gas applications. The drilling additive formulations disclosed herein include at least one fatty acid composition and a biodiesel. The drilling additive formulations for NAF may include biodiesel as a solvent or diluent instead of conventional hydrocarbon solvents, such as mixtures of alkanes. The fluid additive formulation includes at least two active components — the at least one fatty acid composition and the biodiesel. The biodiesel hydrolyzes in situ in drilling fluid to yield fatty acid products which further work as active components of the drilling additive formulation. The drilling additive formulations, devices, systems, methods of manufacturing, and methods of using the drilling additive formulations are particularly useful in downhole applications, such as NAF compositions for use in a drilling fluid.

[0041] A number of benefits can be realized by using biodiesel as a solvent or diluent in a drilling additive formulation. For example, formulations described herein including biodiesel may have a lower viscosity than formulations including hydrocarbons, fatty acids, water or the like as a solvent or diluent. Additionally, the formulations including biodiesel disclosed herein may have a lower pour point than formulations including alkanes, fatty acids, water, or the like as a solvent or diluent. Formulations including biodiesel in combinations with fatty acid compositions disclosed herein may provide reduced corrosivity compared to fatty acid compositions that do not include biodiesel because fatty acids are more corrosive than biodiesel. Notably, biodiesel may also be significantly lessAttorney Docket No. IS24.1206-WOcostly than alternative NAF components such as mixtures of alkanes or tall oil fatty acids (TOFA). Further benefits and embodiments are disclosed below.

[0042] FIG. 1 is a schematic representation of a drilling system 100 for drilling an earth formation 101 to form a borehole 102 defining a wellbore 112, according to at least some embodiments. The drilling system 100 includes a drill rig 103 used to turn a drilling tool assembly 104 which extends downward into the borehole 102 and / or wellbore 112. The drilling tool assembly 104 may include a drill string 105, a bottomhole assembly (“BHA”) 106, and a bit 110, attached to the downhole end of drill string 105. The wellbore 112 may be used to facilitate one or more of hydrocarbon recovery from the earth formation 101, carbon storage in the earth formation 101 (such as by injection of carbon dioxide into the earth formation 101 injection of other fluids into the earth formation 101, stimulation of geological formations for hydrogen generation and / or carbon dioxide storage, or other processes.

[0043] The drill string 105 may include several joints of drill pipe 108 connected end-to-end through tool joints 109. The drill string 105 transmits drilling fluid through a central bore and transmits rotational power from the drill rig 103 to the BHA 106. In some embodiments, the drill string 105 may further include additional components such as subs, pup joints, etc. The drill pipe 108 provides a hydraulic passage through which drilling fluid is pumped from the surface. The drilling fluid discharges through selected-size nozzles, jets, or other orifices in the bit 110 for the purposes of cooling the bit 110 and cutting structures thereon, and for lifting cuttings out of the borehole 102 or wellbore 112 as it is being drilled.

[0044] The BHA 106 may include the bit 110 or other components. An example BHA 106 may include additional or other components (e.g., coupled between to the drill string 105 and the bit 110). Examples of additional BHA components include drill collars, stabilizers, measurement-while-drilling (“MWD”) tools, logging-while-drilling (“LWD”) tools, downhole motors, underreamers, section mills, hydraulic disconnects, jars, vibration or dampening tools, other components, or combinations of the foregoing. The BHA 106 may further include a rotary steerable system (RSS). The RSS may include directional drilling tools that change a direction of the bit 110, and thereby the trajectory of the wellbore 112. At least a portion of the RSS may maintain a geostationary position relative to an absoluteAttorney Docket No. IS24.1206-WOreference frame, such as gravity, magnetic north, and / or true north. Using measurements obtained with the geostationary position, the RSS may locate the bit 110, change the course of the bit 110, and direct the directional drilling tools on a projected trajectory.

[0045] In general, the drilling system 100 may include other drilling components and accessories, such as special valves (e.g., kelly cocks, blowout preventers, and safety valves). Additional components included in the drilling system 100 may be considered a part of the drilling tool assembly 104, the drill string 105, or a part of the BHA 106 depending on their locations in the drilling system 100.

[0046] The bit 110 in the BHA 106 may be any type of bit suitable for degrading downhole materials. For instance, the bit 110 may be a drill bit suitable for drilling the earth formation 101. Example types of drill bits used for drilling earth formations are fixed-cutter or drag bits. In other embodiments, the bit 110 may be a mill used for removing metal, composite, elastomer, other materials downhole, or combinations thereof. For instance, the bit 110 may be used with a whipstock to mill into casing 107 lining the wellbore 112. The bit 110 may also be a junk mill used to mill away tools, plugs, cement, other materials within the borehole 102, or combinations thereof. Swarf or other cuttings formed by use of a mill may be lifted to the surface or may be allowed to fall downhole.

[0047] A wellbore fluid (e.g., a drilling fluid) may be used during drilling operations to lubricate and cool the bit 110 and remove cuttings from the earth formation 101. The drilling fluid may be configured to be circulated through the drill string 105, out of the drill string 105 through the bit 110, and into the annulus between the drill string 105 and the surfaces of the earth formation 101 defining the borehole 102 (or the wellbore 112). For example, a surface pump 114 may pump the drilling fluid from a mud pit 116 which holds the drilling fluid. In some embodiments, one or more additives may be added to the drilling fluid, such as by providing the one or more additives to the mud pit 116.

[0048] The drilling fluid may be used to facilitate lubrication and cooling of the bit 110 and removal of cuttings of the earth formation 101 from the borehole 102 and / or wellbore 112. The drilling fluid may include one or more materials formulated and configured to facilitate drilling of the earth formation 101. The drilling fluid may include a drilling additive formulation having a fatty acid composition and a biodiesel. The drilling additive formulation is composed and configured to cause one or more of pour point depression,Attorney Docket No. IS24.1206-WOdecreased viscosity, fluid loss control, increased wetting, or the like compared to formulations that do not include biodiesel. In addition, the drilling additive formulations may further include one or more additives, such as at least one amidoamine, butoxytriglycol (BTG), or any of the additives disclosed herein. In some embodiments, the drilling additive formulations is free of conventional NAFs not having the formula of the drilling additive formulations disclosed herein. For example, the drilling additive formulations may be free of TOFA, conventional diesel fuel, or alkane solvents.

[0049] As discussed in more detail herein, the drilling fluid may include a base fluid, drilling additive formulations disclosed herein, and one or more secondary additives such as emulsifiers, surfactants, bridging materials, viscosifiers, thinners (e.g., dispersion aids), wetting agents, weighting materials, filtration control agents, shale stabilizers, pH buffers, scavengers, emulsion activators, oxygen scavengers, gelling agents, scale inhibitors, foaming agents, fluid loss agents, defoamers, solvents, rheological additives, or other additives. The secondary additives may be used in combination with the drilling additive formulations disclosed herein. For example, the drilling additive formulation may act as a fluid loss agent, emulsifier, and wetting agent, while secondary emulsifiers may be present in the drilling fluid or drilling additive formulation therein to provide additional emulsification functionality.

[0050] In some embodiments, the drilling fluid is an aqueous-based drilling fluid (e.g., a water-based drilling fluid) and may be referred to as “drilling fluid,” an “emulsion drilling fluid,” or a “drilling mud.” The drilling fluid may include an emulsion wherein the continuous external phase is aqueous, and the internal discontinuous phase is oleaginous.

[0051] In some embodiments, the drilling fluid is a nonaqueous-based drilling fluid (e.g., an oil-based drilling fluid, a synthetic-based drilling fluid) and may be referred to as a “NAF, an “invert drilling fluid,” an “invert emulsion drilling fluid,” or a “drilling mud.” The drilling fluid may include an invert emulsion wherein the continuous external phase is oleaginous, and the internal discontinuous phase is aqueous.

[0052] In embodiments where the drilling fluid includes a nonaqueous-based drilling fluid, such as an oil-based drilling fluid or a synthetic-based drilling fluid, the base fluid may include an oleaginous or oil-based fluid, such as a natural or synthetic oil. In some embodiments the oleaginous fluid is selected from the group consisting of at least one ofAttorney Docket No. IS24.1206-WOdiesel oil, mineral oil, a synthetic oil, (e.g., hydrogenated and unhydrogenated olefins including polyalpha olefins, linear and branched olefins), a mixture of alkanes with a carbon chain length ranging from CIO to C20 (e.g., Saraline 185V, commercially available from Shell PLC of London, England), polydi organosiloxanes, siloxanes, organosiloxanes, or esters of fatty acids (e g., straight chained, branched and cyclical alkyl ethers of fatty acids). In some embodiments, the base fluid includes a mixture of C16 to C18 internal olefins (an alkene in which the double bond is within the carbon chain rather than at a terminal portion (at the alpha position) of the carbon chain).

[0053] An internal phase of an emulsion of the oleaginous or oil-based fluid may include one or more salts. The one or more salts may provide a desired density to the drilling fluid and may also reduce the effect of the drilling fluid on hydratable clays and shales in the earth formation 101. The salts may include salts of one or more of sodium, calcium, aluminum, magnesium, zinc, potassium, strontium, or lithium, and salts of one or more of chlorides, bromides, carbonates, iodides, chlorates, bromates, formates, nitrates, oxides, phosphates, sulfates, silicates, or fluorides. In some embodiments, the salt includes a divalent halide, such as an alkaline earth halide (e.g., calcium chloride (CaCh), calcium bromide (CaBn)), or a zinc halide. The salt may include cesium formate (HCOOCs), sodium bromide (NaBr), potassium bromide (KBr), and cesium bromide (CsBr). The particular composition of the salt may be selected based on compatibility with the earth formation 101 and / or to match the brine phase of a completion fluid and / or a nonaqueous fluid. In some embodiments, the salt includes calcium chloride.

[0054] The salt may constitute from about 5.0 weight percent (wt %) to about 30.0 wt % of the drilling fluid, such as from about 5.0 wt % to about 10.0 wt %, from about 10.0 to about 20.0 wt%, or from about 20.0 wt % to about 30.0 wt% of the drilling fluid. However, the disclosure is not so limited, and the weight percent of the salt and the water in the drilling fluid may be different than that described.

[0055] The embodiments disclosed herein use biodiesel as a diluent, solvent, and / or active component in fatty acid-containing drilling additive formulations. The drilling additive formulations disclosed herein include NAFs for use in oil and gas applications. As described in more detail below, the fatty acid compositions within the drilling additive formulations may include at least one C8 to C20 saturated, monounsaturated, orAttorney Docket No. IS24.1206-WOpolyunsaturated fatty acid, such as a Cl 6 to C20 saturated, monounsaturated, or polyunsaturated fatty acid. In some embodiments, the fatty acid(s) make up 60 weight percent (wt %) or less of the drilling additive formulation and the biodiesel is less than 50 wt % of the drilling additive formulation. Various fatty acids may be used in the drilling additive formulations disclosed herein.

[0056] One or more fatty acids present in the drilling additive formulation may be referred to as a fatty acid composition. Such fatty acid compositions may include a mixture of fatty acids or a single fatty acid. Fatty acid compositions including one or more fatty acids work particularly well as emulsifiers and wetting agents in the drilling additive formulations disclosed herein.

[0057] One or more components of the drilling additive formulations (e.g., NAFs) may be derived, at least partially from, vegetable oils and may include a mixture of unsaturated fatty acids and saturated fatty acids which are present in the vegetable oils. In some embodiments, the saturated fatty acids may include linear saturated fatty acids that are naturally occurring (e.g., present in vegetable oils and / or present in animal fats) and may be linear saturated fatty acids.

[0058] In some embodiments, the drilling fluid additive formulation includes fatty acids that are sourced from vegetable oils and / or from animals and may include one or more unsaturated fatty acids and one or more saturated fatty acids. The drilling additive formulations may include fatty acids that are not sourced from tall oil (an oil produced by conifer trees). Thus, the drilling additive formulations may be substantially free of tall oil fatty acids (TOFAs), sourced from tall oil. In some embodiments, the drilling additive formulation includes C18 fatty acids, such as oleic acid, linoleic acid, and a-linolenic acid, but not from tall oil. Vegetable oils that include saturated fatty acids are not conventionally used in the production of drilling additive formulations (e.g., NAF drilling additive formulations) because the saturated fatty acids crystalize in a structuring effect wherein the crystals exhibit long range interactions and form a solid network or large networks of crystals that prevents the flow of the drilling additive formulation.

[0059] In some embodiments, the one or more fatty acids (e.g., fatty acid composition) of the drilling additive formulation are sourced from one or more vegetable oils, such as one or more of canola oil, safflower oil, flaxseed oil, sunflower oil, corn oil, soybean oil,Attorney Docket No. IS24.1206-WOcottonseed oil, peanut oil, olive oil, rapeseed oil, almond oil, grape seed oil, linseed oil, oiticica oil, poppyseed oil, sesame oil, tung oil, walnut oil, algae oil, palm oil, and wheat germ oil. In some embodiments, the one or more fatty acids are sourced from canola oil. In some embodiments, the one or more fatty acids are sourced from safflower oil, flaxseed oil, sunflower oil, or com oil. By way of nonlimiting example, the vegetable oils may include glycerides (e.g., triglycerides), which may be hydrolyzed to form fatty acids that make up the glycerides, and one or more alcohols (e.g., glycerol). In addition, the one or more fatty acids of the drilling additive formulation may be sourced from animals. In some embodiments, the one or more fatty acids includes a mixture of one or more fatty acids derived from one or more vegetable sources, and one or more fatty acids derived from one or more animal sources. In some embodiments, the one or more fatty acids are sourced from animals are derived from tallow (e.g., solid animal fat (e.g., suet) from beef, lamb, mutton, and / or another animal).

[0060] As described above, the fatty acid composition may include one or more unsaturated fatty acids and one or more saturated fatty acids. The unsaturated fatty acids and the saturated fatty acids of the fatty acid composition may be naturally occurring (e.g., derived from plants, such as from vegetable oils; and / or derived from animal sources). The fatty acids may be linear, branched, or may include one or more cyclic groups. The unsaturated fatty acids may include a monounsaturated fatty acid having one carbon to carbon double bond; a diunsaturated fatty acid having two carbon to carbon double bonds; a triunsaturated fatty acid having three carbon to carbon double bonds; a tetraunsaturated fatty acid having four carbon to carbon double bonds; a pentaunsaturated fatty acid having five carbon to carbon double bonds; a hexaunsaturated fatty acid having six carbon to carbon double bonds; or any other polyunsaturated fatty acid having more than one carbon to carbon double bond. In some embodiments, the fatty acid composition includes one or more monounsaturated fatty acids, one or more diunsaturated fatty acids, one or more triunsaturated fatty acids, or combinations of any of the foregoing.

[0061] The unsaturated fatty acid of the fatty acid composition may include one or more of linolenic acid (e.g., a-linolenic acid and / or y-linolenic acid), stearidonic acid, eicosapentaenoic acid, cervonic acid, linoleic acid, linolelaidic acid, arachidonic acid,Attorney Docket No. IS24.1206-WOdocosatetranoic acid, palmitoleic acid, vaccenic acid, paullinic acid, oleic acid, elaidic acid, erucic acid, crotonic acid, myristoleic acid, sapienic acid, gadoleic acid, or eicosenoic acid.

[0062] The saturated fatty acids of the fatty acid composition may include one or more of valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nonadecylic acid, arachidic acid, behenic acid, tricosylic acid, lignoceric acid, pentacosylic acid, cerotic acid, carboceric acid, montanic acid, nonacosylic acid, meliisic acid, lacceroic acid, or psyllic acid. In some embodiments, the saturated fatty acids include C16 and / or C18 saturated fatty acids. For example, the saturated fatty acids may include one or both of palmitic acid and stearic acid. In some embodiments, the saturated fatty acids include C12 fatty acids, such as lauric acid. In some embodiments, the saturated fatty acids include linear saturated fatty acids and may be naturally occurring, such as saturated fatty acids sourced from plants (e.g., vegetable oils) and / or animals.

[0063] Due to the relatively high pour point of saturated fatty acids, saturated fatty acids are not commonly used as drilling additive formulations of NAFs. Since the fatty acid compositions of the drilling additive formulations herein may include some saturated fatty acids, the drilling additive formulations may be at least partially derived from sources that include some saturated acids, increasing the availability and decreasing the costs associated with forming the drilling additive formulations. For example, the fatty acid composition(s) may be derived from vegetable sources or animal sources as described above. Fatty acid compositions using saturated fatty acids may benefit from dilution or dissolution in another component of the drilling additive solution, such as biodiesel, to provide one or more selected properties (e.g., viscosity, pour point) or functionalities (e.g., emulsifier, wetting agent) to the drilling additive formulation.

[0064] In some embodiments, the unsaturated fatty acid(s) of the fatty acid composition includes one or more unsaturated C 18 fatty acids, such as one or more of oleic acid, linoleic acid, linolelaidic acid, a-linolenic acid, y-linolenic acid, or stearidonic acid. In some embodiments, the unsaturated fatty acid of the fatty acid composition includes unsaturated fatty acids including each of oleic acid, linoleic acid, and a-linolenic acid; and saturated fatty acids including one or both of stearic acid and palmitic acid.Attorney Docket No. IS24.1206-WO

[0065] In some embodiments, one or more components of the fatty acid composition may have a relatively higher melting temperature than a predetermined temperature (e.g., a desired pour point of the drilling additive formulation). By way of nonlimiting example, the unsaturated fatty acid may include elaidic acid. As described herein, the fatty acid composition may be formulated as a wax inhibitor and may reduce and / or prevent the formation of wax crystals that cause agglomeration and an increase in the pour point of the fluid additive formulation including such unsaturated fatty acids.

[0066] The types of unsaturated acids and saturated acids, as well as the relative amounts of the unsaturated acids and the saturated fatty acids, may depend at least in part, on the vegetable oils from which the fatty acids are derived. In some embodiments, the saturated fatty acids include one or more C18 saturated fatty acids and one or more C16 saturated fatty acids. The saturated fatty acids may further include one or more C12 saturated fatty acids. In some embodiments, the wetting agent comprises, consists essentially of, or consists of one or more of oleic acid, linoleic acid, ot-linolenic acid, palmitic acid, stearic acid, or combinations of any of the foregoing. In some embodiments, depending on the vegetable oil(s) from which the fatty acids are derived, the fatty acid composition may further include abietic acid (which may be present in the form of rosin).

[0067] In some embodiments, a weight ratio of monounsaturated fatty acids (e.g., oleic acid) to polyunsaturated (e.g., one or more of linoleic acid, linolenic acid) fatty acids in the fatty acid composition is within a range of from about 1.0:0.1 to about 1.0:5.0 by weight of the fatty acid composition, such as from about 1.0:0.1 to about 1.0:0.2, from about 1.0:0.2 to about 1.0:0.5, from about 1.0:0.5 to about 1.0: 1.0, from about 1.0: 1.0 to about 1.0:2.0, from about 1.0:2.0 to about 1.0:3.0, from about 1.0:3.0 to about 1.0:5.0 by weight. In some embodiments, the fatty acid composition includes a higher weight percent of monounsaturated fatty acids than a weight percent of polyunsaturated fatty acids. In some embodiments, the fatty acid composition includes a higher weight percent of polyunsaturated fatty acids than of monounsaturated fatty acids.

[0068] A weight percent of unsaturated fatty acids in the fatty acid composition may be within a range of from about 70.0 weight percent to about 99.0 weight percent, such as from about 70.0 weight percent to about 75.0 weight percent, from about 75.0 weight percent to about 80.0 weight percent, from about 80.0 weight percent to about 85.0 weightAttorney Docket No. IS24.1206-WOpercent, from about 85.0 weight percent to about 90.0 weight percent, from about 90.0 weight percent to about 95.0 weight percent, or from about 95.0 weight percent to about 99.0 weight percent. In some embodiments, unsaturated fatty acids constitute less than about 95.0 weight percent, such as less than about 90.0 weight percent, less than about 85.0 weight percent, or less than about 80.0 weight percent of the fatty acids in the drilling additive formulation.

[0069] A weight percent of monounsaturated fatty acids in the fatty acid composition may be within a range of from about 10.0 weight percent to about 80.0 weight percent of the fatty acid composition, such as from about 10.0 weight percent to about 20.0 weight percent, from about 20.0 weight percent to about 40.0 weight percent, from about 40.0 weight percent to about 60.0 weight percent, or from about 60.0 weight percent to about 80.0 weight percent. In some embodiments, monounsaturated fatty acids constitute greater than about 40.0 weight percent, such as greater than about 50.0 weight percent, greater than about 60.0 weight percent, or greater than about 70.0 weight percent of the fatty acids in the drilling additive formulation.

[0070] A weight percent of polyunsaturated fatty acids in the fatty acid composition (e.g., wetting agent) may be within a range of from about 10.0 weight percent to about 80.0 weight percent of the fatty acid composition, such as from about 10.0 weight percent to about 20.0 weight percent, from about 20.0 weight percent to about 30.0 weight percent, from about 30.0 weight percent to about 40.0 weight percent, from about 40.0 weight percent to about 60.0 weight percent, or from about 60.0 weight percent to about 80.0 weight percent of the fatty acids in the drilling additive formulation.

[0071] In some embodiments, the drilling additive formulation (e.g., NAF) includes greater than about 2.0 weight percent saturated fatty acids (such as greater than about 3.0 weight percent, or greater than about 5.0 weight percent saturated fatty acids).

[0072] In some embodiments, the fatty acid composition additionally or alternatively includes one or more maleated fatty acids. Maleated fatty acids may have one or more moieties (e.g., maleic anhydride, maleate) thereon that cause the maleated fatty acids to have a higher acid number than the base fatty acid (e.g., the same nonmaleated fatty acid). Such moieties include a maleic anhydride. Suitable maleated fatty acids may include maleated forms of any of the fatty acids disclosed herein. For example, the maleated fattyAttorney Docket No. IS24.1206-WOacid(s) may include the maleated form of any of the unsaturated fatty acids disclosed herein, such as maleated internal mono- or polyunsaturated C12-C20 fatty acids. In some embodiments, the maleated fatty acid includes maleated TOFA, wherein the maleated fatty acid is 80 weight percent (wt %) or less of the drilling additive formulation and the biodiesel is less than 50 wt % of the drilling additive formulation. Suitable maleated fatty acids may include one or more of maleated TOFA, maleated tallow oil fatty acids, maleated fish oil fatty acids, or the like. Suitable maleated fatty acids may include a mixture of maleated oleic and linoleic acids. Suitable maleated fatty acids may include maleated C 12-C20, C16-C20, Cl 8 fatty acids, or mixtures thereof. Such maleated fatty acids may include one or more of saturated and unsaturated fatty acids. Maleated fatty acids are particularly useful as fluid loss additives in the drilling additive formulations disclosed herein.

[0073] Based on a selected functionality (e.g., viscosifier, emulsifier, wetting agent, fluid loss agent) or properties of the fatty acid composition in the drilling additive formulation, the weight percentage of the fatty acid composition in the drilling additive formulation may be correspondingly selected. For example, the fatty acid composition may be at least 5 weight% of the drilling additive formulation, such as about 5 wt % to about 90 wt %, about 10 wt % to about 80wt%, about 5 wt% to about 70wt%, about 10 wt% to about 50 wt %, about 5 wt % to about 25 wt %, about 20 wt % to about 40 wt %, about 25 wt % to about 50 wt %, about 50 wt % to about 80 wt %, more than about 25 wt %, more than about 30wt %, more than about 50 wt %, more than about 65 wt %, more than about 70 wt %, less than about 90 wt %, less than about 80 wt %, less than about 60 wt %, less than about 50 wt %, or less than about 30 wt % of the drilling additive formulation.

[0074] The drilling additive formulations disclosed herein include a biodiesel in addition to the fatty acid composition. As noted above, biodiesel provides a number of benefits over alternative chemicals, such as TOFA, conventional diesel, or alkanes. For example, biodiesel may be less costly than TOFA or alkanes. Biodiesel may provide a renewably sourced component for drilling additive formulations. Biodiesel provides a balance of viscosity, pour point, and chemical convertibility to active agents in situ in drilling mud that other chemicals to not provide. Additionally, biodiesel has better solvent properties because it is more polar than base oils.Attorney Docket No. IS24.1206-WO

[0075] As described herein, the drilling additive formulations include biodiesel as a component, such as a diluent or a solvent, and ultimately as an active component. Biodiesel by definition, is composed of fatty acid methyl esters (FAME) made from tall oil fatty acids (TOFA) or vegetable sourced fatty acids. Accordingly, biodiesel is a green chemical formed from plant products and therefore may be more desirable than (synthetic) diesel, mixtures of alkanes, or other synthetic NAFs from an environmental standpoint. Biodiesel includes predominantly C18 monounsaturated and polyunsaturated fatty acid methyl esters with a smaller quantity of C16 and or C18 saturated methyl esters. Furthermore, purification may also be done on these fatty acid methyl esters to remove trace water and glycerin or crude with residual water, some glycerin, or incompletely converted vegetable oils (mono glycerides, diglycerides, and some triglycerides). In some embodiments, the biodiesel in the drilling additive formulations may include biodiesel fitting the definition disclosed in ASTM D6751 Standard Specification for Biodiesel Fuel Blend Stock (Bl 00) for Middle Distillate Fuels, the disclosure of which is incorporated herein in its entirety, by this reference.

[0076] In some embodiments, FAMEs outside of the definition provided in ASTM D6751 noted above may be used as biodiesel. For example, methyl oleate from non-TOFA sources may be used as biodiesel. There are different FAMEs and blends thereof that can be used as biodiesel, such as methyl oleate, methyl linoleate, methyl linolinate, and / or or at least one FAME based on saturated or unsaturated C2-C22 fatty acids. In some embodiments, FAME(s) can be composed in different ratios. Examples where FAME of oleic and linoleic acids (or other polyunsaturated acids) are used are expected to have even lower pour points compared to examples of biodiesel according to ASTM D6751 noted above, which may be further advantageous. Accordingly, “FAME” may be used as “biodiesel” for the purposes of this disclosure.

[0077] Using other (fatty acid) esters for a “biodiesel” besides the methyl ester would reduce polarity of the (fatty acid) ester and reduce its ability to dissolve additives. Furthermore, when biodiesel hydrolyzes it produces 95% by weight wetting agents (e.g., fatty acids) and some alcohol. Esters with larger alkyl chains than a methyl ester (e.g., greater than a C4 alkyl chain) would produce less wetting agent upon hydrolysis but more of the undesired alcohol. While fatty acid methyl esters are preferred based on their polarityAttorney Docket No. IS24.1206-WOand relatively low viscosity, in some embodiments, the fatty acid ester may be an ethyl, propyl, or butyl ester.

[0078] While in theory, other esters (such as fatty acid esters based on other monofunctional, difunctional, and polyfunctional alcohols and esters based on other organic acids such as C 1 to C 18 acids, linear or branched) could be used, and low molecular weight esters can be tuned for even better performance than biodiesel, biodiesel provides benefits and solutions that such other esters do not. For example, low molecular weight esters have a lower flash point than the methylated esters (e.g., biodiesel) disclosed herein, which is a health and safety risk. Biodiesel is expected to be more compatible in drilling fluid solutions of NAF than low molecular weight esters because biodiesel is structurally similar to oleic acid or other wetting agents, which have been used in drilling mud. It is also suspected that lower molecular weight esters can negatively affect elastomers. Notably, biodiesel will hydrolyze in drilling mud to make the fatty acids which have been used in drilling mud, such as for wetting agents.

[0079] By itself, biodiesel as a wetting agent is unlikely to be very effective because it takes time and heat to hydrolyze the (methyl) esters therein and until this happens there is no wetting agent (free fatty acids) present in biodiesel since low acid value is a typical biodiesel specification. However, “failed” or off-spec batches of biodiesel can be used as stand-alone wetting agents or as a diluent in examples disclosed herein. A “bad,” “failed,” or “off-spec” biodiesel batch includes a combination of methyl esters, fatty acids, and possibly some glycerin. Moreover, it has been shown that glycerin byproduct is not problematic to NAF so “bad” batches of biodiesel may be as effective for use in the drilling additive formulations of this disclosure as “good” batches of biodiesel. An advantage of “off-spec” biodiesel is that product is likely to be cheaper since material cannot be used as a component of a diesel fuel. Such failed or off-spec biodiesel can be used as the biodiesel in the drilling additive formulations disclosed herein. Such failed or off-spec biodiesel may have a higher acid number than a “good” biodiesel (having a lower acid number).

[0080] The biodiesel may be at least 5 wt % of the drilling additive formulation, such as about 5 wt % to about 90 wt %, about 10 wt % to about 90 wt %, about 20 wt % to about 80 wt %, about 5 wt % to about 50 wt %, about 50 wt % to about 90 wt %, about 5 wt % to about 30 wt %, about 30 wt % to about 60 wt %, about 5 wt % to about 35 wt %, aboutAttorney Docket No. IS24.1206-WO35 wt % to about 65 wt %, at least about 20 wt %, at least about 35 wt %, less than about 90 wt %, less than about 80 wt %, less than about 70 wt %, less than about 50 wt %, or less than about 35 wt % of the drilling additive formulation. At least some of the remainder of the drilling additive formulation may include the fatty acid composition (e.g., one or more fatty acids), such as for use as a wetting agent. The relative amount of biodiesel compared to the fatty acid composition in the drilling additive formulations disclosed herein may be selected to provide one or more properties or levels of functionality to the drilling additive formulation of NAF. For example, a higher concentration of biodiesel may provide a depressed pour point and lower viscosity than a drilling additive formulation with a higher concentration of fatty acids. However, such an example may provide fluid loss and / or wetting benefits for a longer duration due to the time needed for conversion of biodiesel into fatty acids via hydrolysis during use. Accordingly, the relative amounts of components may be selected based on a selected property or functionality of the resulting drilling additive formulation. For example, biodiesel may act as one or more of a diluent, a solvent, or an active agent (e.g., wetting agent) in the drilling additive formulations disclosed herein.

[0081] In some embodiments, the drilling additive formulations disclosed herein have a pour point of 0 °C or less, such as -6 °C or less.

[0082] In some embodiments, the drilling additive formulation may include one or more maleated fatty acids in combination with biodiesel. In such embodiments, the one or more maleated fatty acids of the fatty acid composition may function as a fluid loss agent in situ in an oil and gas drilling environment. For example, a maleated fatty acid may be a maleated TOFA. In such embodiments, the maleated fatty acid and biodiesel may be present in any of the amounts disclosed herein, such as where the maleated fatty acid is 60 wt % or less of the drilling additive formulation and the biodiesel is less than 50 wt % of the drilling additive formulation.

[0083] As noted above, maleated fatty acid works for fluid loss reduction. However, this chemistry is difficult to formulate in typical drilling solvents such as base oils (e.g., mixtures of alkanes) due to the insolubility of maleated fatty acid in such solvents. Such difficulty is suspected to be due to insufficient polarity of the base oils. Addition of glycols like butoxytriglycol (BTG) or butoxydiglycol (BDG) as a solvent for the maleated fattyAttorney Docket No. IS24.1206-WOacid may also cause issues because maleated fatty acid contains an anhydride functionality which will react with glycol reactants to form products (e.g., ester(s)) not originally intended to be present in a drilling additive formulation. Accordingly, the amount of the glycol(s) may be limited to a relatively small amount (e.g., less than about 20 wt %, less than about 15 wt %, or less than about 10 wt%) of the drilling additive formulation. Additionally, pretreating the maleated fatty acid(s) with water to hydrolyze any maleated anhydride moieties in the maleated fatty acids may be carried out at least to avoid the undesirable reaction between the glycol and the anhydride moieties. Such hydrolysis pretreatment is described in more detail below.

[0084] Maleated fatty acid can be formulated in aqueous form after neutralization with potassium as K-salt. FIG. 2 is a graph of viscosity of maleated fatty acid in aqueous form at different concentrations. For FIG. 2, maleated TOFA (Tenax® 2010 from Ingevity of North Charleston, South Carolina, U.S.A., also referred to as Tenax 2010) in aqueous form after neutralization with a potassium as a K-salt was tested at various concentrations of the maleated TOFA. Viscosity measurements were taken at 30 wt %, 40 wt %, 45 wt %, and 50 wt % of maleated TOFA in the aqueous solution. As shown, viscosity at 4-5 °C at 30 wt % maleated TOFA was 35 centipoise (cps), at 40 wt % maleated TOFA was 384 cps, at 45 wt % maleated TOFA was 2180 cps, and at 50 wt % maleated TOFA was 10,800 cps.

[0085] Based on FIG. 2, viscosity increases significantly at increased concentrations of the maleated TOFA (eg., active ingredient). Accordingly, drilling additive formulations having maleated fatty acids (e.g., TOFA) are expected to have undesirably high viscosity as the concentration of the maleated fatty acid increases. The NAF drilling additive formulations disclosed herein provide relatively low viscosity due to the biodiesel despite having relatively high fatty acid concentrations, thereby saving wellsite space. While NAF compositions are disclosed herein, the aqueous samples of FIG. 2 were tested in an aqueous solvent to investigate the properties of maleated TOFA in solution. Aqueous formulations will freeze around 0 °C which is not desirable. Accordingly, a pour point depressant and solvent / diluent with low viscosity is desirable when using maleated fatty acids in a drilling additive formulation, such as for a fluid loss additive. As discussed in more detail herein, biodiesel mixed with the maleated fatty acid(s) provides a surprisingly effective solutionAttorney Docket No. IS24.1206-WObased on each of cost, viscosity, chemistry to form an active agent (e.g., free fatty acid wetting agent and / or fluid loss additive), and low temperature performance.

[0086] Maleated fatty acid samples in various solvents were tested to determine viscosity and pour point characteristics. Table 1 below shows the viscosity and low temperature performance observations of maleated fatty acid compositions in various solvents. Four sample maleated fatty acid compositions were prepared and tested. A first sample included 60 wt % maleated fatty acid in biodiesel, the second sample included 30 wt % maleated fatty acid in TOFA, the third sample included 30 wt % maleated fatty acid in water, and the fourth sample included a commercial blend containing malleated fatty acids, fatty acids, and other additives in conventional hydrocarbon solvent and a glycol pour point. The samples were tested for viscosity at 4 °C and observations were made about low temperature performance (e.g., at about 0 °C or less) of the samples.

[0087] The samples were cooled to in a cooler until a stable temperature of 4 °C was reached. A Brookfield Viscometer was used to test viscosity of the samples at 4 °C. The viscosity number was recorded after the reading stabilized. Test ran about 30 min.

[0088] Table 1: Viscosity of various formulations of maleated fatty acid products in different solvents.Attorney Docket No. IS24.1206-WO

[0089] As shown, the first sample with 60 wt% maleated fatty acid in biodiesel had a viscosity (at 4 °C) of 1200 centipoise (cps) and remained liquid at 0 °C. The second sample of 30 wt % maleated fatty acid in TOFA had a viscosity of 1600 cps and was cloudy. The third sample with 30wt % malleated fatty acid in water has a viscosity of 35 cps and remained thin until it froze at about -1 to -2 °C. The fourth sample of Novatec F (filtration control additive available from SLB of Houston Texas, U.S.A) had a viscosity of 5300 cps and was expected to be unsuitable for low temperature operations due to the relatively high viscosity.

[0090] Notably, the first sample had a higher concentration of maleated fatty acid therein than any of the second through fourth samples, including double the amount of maleated fatty acid in samples 1 and 2. Despite the relatively high amount of maleated fatty acid in the first sample, the first sample had a surprisingly low viscosity and remained liquid at 0 °C. Accordingly, Table 1 demonstrates maleated fatty acid in biodiesel provides relatively low viscosity at a relatively high percent fatty acid content (e.g., maleated fatty acid actives) and provides low temperature performance at or below 0 °C. Moreover, additional benefits of using biodiesel versus a fatty acid mixture (e.g., TOFA) include the relatively lower viscosity of biodiesel formulations and reduced corrosivity since fatty acids are considered slightly corrosive.

[0091] Performance of maleated fatty acid as a drilling fluid additive is concentrationdependent and increasing the concentration of the active ingredient in the formulation can be advantageous to reduce the volume of treatment (e.g., fluid loss additive) that needs to be applied to achieve a selected property in the drilling mud. Various samples of maleated fatty acid compositions in selected formulations were made and tested for fluid loss using hot roller tests. Additional physical properties of each sample were tested as well including rheology, plastic viscosity, yield point, low shear yield point, gel strength, and electrical stability. The testing protocols used to test the various properties of the sample compositions are described in API 13B-2, “Recommended Practice for Field Testing Oil-Based Drilling Fluids” (available from the American Petroleum Institute of Washington DC, U.S.A ).

[0092] Table 2 below shows fluid loss data from drilling mud sample compositions including a MEGADRIL (oil-based temperature-stable invert-emulsion drilling fluidAttorney Docket No. IS24.1206-WOavailable from SLB) blank sample, a 6 pounds per barrel (Ibm / bbl) Novatec F (maleated rosin polymer glycol ether used as a fluid-loss reducer, available from SLB of Houston Texas, U.S.A) sample, a 4 Ibm / bbl Novatec F sample, and a 4 Ibm / bbl Alternative sample having maleated fatty acid (Tenax 2010) in biodiesel. The values for Ibm / bbl density disclosed herein may be the same numerical values expressed in grams per 350 milliliters (g / 350 mL). Table 2 also shows physical properties of the various samples during testing. Such properties include fluid weight, rheology temperature, viscometer reading (at 600 rpm, 300 rpm, 200 rpm, 100 rpm, 600 rpm, 3 rpm), 10 second gel (gelO), 10-minute gel (gel 10), plastic viscosity, yield point, low shear yield point, electrical stability, and HPHT fluid loss at 350 °F. Most of the properties were measured before hot rolling (BHR) and after hot rolling (AHR).

[0093] Table 2: Mud compositions and properties of samples including a Megadril blank, Novatec F at 6 Ibm / bbl and 4 Ibm / bbl, and an Alternative (maleated fatty acid (Tenax 2010)) sample in biodiesel at 4 Ibm / bbl. With the exception of the Megadril blank, the samples compositions were 40 wt % biodiesel and 60 wt % maleated fatty acid.Attorney Docket No. IS24.1206-WO

[0094] Table 2 shows improved fluid loss characteristics with products formulated in biodiesel vs the reference product Novatec F. The MEGADRIL blank shows high fluid loss. The 6 Ibm / bbl Novatec F shows an improvement in fluid loss over the MEGADRIL blank. Reducing concentration of Novatec F to 4 Ibm / bbl still maintains fluid loss control relative to MEGADRIL blank but there is deterioration in performance. The AHR fluid loss measurement of the 4 Ibm / bbl Alternative sample shows improved performance over either 4 Ibm / bbl or 6 Ibm / bbl Novatec F samples at 4 Ibm / bbl loading of the Alternative sample (maleated fatty acid in biodiesel). Since there is clear dose-response relationship shown with the two examples (6 Ibm / bbl and 4 Ibm / bbl) using Novatec F, fluid loss control could be resolved by adding more fluid loss agent (e.g., Novatec F) or increasing the concentration of active ingredient(s) in the additive composition. Only in the case of the Alternative sample (maleated fatty acid combined with biodiesel) is it possible to increaseAttorney Docket No. IS24.1206-WOthe concentration of actives (e.g., fatty acid fluid loss additive or wetting agent) without making the additive composition excessively viscous. Such increase includes conversion of biodiesel into fatty acids during use as disclosed herein.

[0095] An additional benefit of formulating maleated fatty acid in biodiesel is that biodiesel can hydrolyze and generate wetting agent in situ. Esters tend to hydrolyze relatively easy in NAF so using biodiesel as a solvent will generate some amount of fatty acids during usage which acts as an emulsion strength booster and controls gelation (as shown in 10-minute gels in Table 2).

[0096] Additional examples of generation of wetting agent(s) in situ are demonstrated below. Drilling formulations with maleated fatty acids (fluid loss agent) in biodiesel are expected to have similar fluid loss performance to a formulation of maleated fatty acid in TOFA (or other fatty acid), but viscosity of formulations of maleated fatty acids in biodiesel are superior (e.g., lower) compared to maleated fatty acids in TOFA or a similar fatty acid.

[0097] Fatty acids or fatty acid compositions including the fatty acids can be used as wetting agents for drilling additive formulations. Any of the fatty acids disclosed herein may be used as a wetting agent. For example, one or more C8 to C20 (e.g., Cl 8) saturated, monounsaturated, or polyunsaturated fatty acids may be used as a wetting agent. Such fatty acids may include one or more of oleic acid, linoleic acid, linolenic acid, stearidonic acid, or the like. In some embodiments, more than one fatty acid may be present in a wetting agent. Sources of fatty acids can be TOFA and non-TOFA.

[0098] While wetting performance in drilling additive formulations of NAF for many of the fatty acids is similar, there are problems with high pour points of these drilling additive formulations. One way to solve this pour point issue is by adding wax inhibitor additives. Using wax inhibitors can be used in combination with dilution to hit certain cost targets but at the cost of reduced performance.

[0099] Using at least one diluent solvent is useful to reduce cost but at the expense of reduced performance. For example, 30% dilution of TOFA or non-TOFA wetting agent will reduce performance by 30% and the solvent does not provide any performance value. However, dilution with biodiesel is expected to reduce activity of the drilling additive formulation by a lower factor than other solvents. “Activity” refers to active ingredients inAttorney Docket No. IS24.1206-WOan additive composition, where the active ingredients perform one or more selected functions within the drilling fluid to which the additive composition is added. Such functions may include viscosity modification, fluid loss prevention, wetting enhancement, or the like. However, such functions do not include dilution or solvent functions, so most solvents to not provide “activity.” However, during use, the biodiesel solvents disclosed herein hydrolyze to form fatty acids which are active ingredients. In other words, a wetting agent (e.g., fatty acid composition) diluted by 30% with biodiesel will reduce performance by less than 30%, as shown in Table 3 below. In such example drilling additive formulations, the biodiesel may be less than 50 wt % of the drilling additive formulation, such as about 10 wt % to about 50 wt %. In some embodiments, where further dilution is desired, the biodiesel may be 70 wt % or less of the drilling additive formulation. The biodiesel may include any of the biodiesel fuels disclosed herein, such as one or more fatty acid methyl esters, an off-spec biodiesel fuel, or the like.

[0100] Tests were carried out to determine various properties of wetting agent compositions including fatty acids (oleic acid) and various solvents.

[0101] Table 3 below is a rheology and fluid loss comparison between samples of drilling additive formulations having a fatty acid composition (e.g., oleic acid wetting agent) and a selected solvent / diluent. The fatty acid composition used in the samples was Surewet™ (available from SLB of Houston, Texas, U.S.A.). A control sample of the fatty acid composition alone was used as a blank. The first solvent / diluent was Saraline 185V (a mixture of alkanes used as a base oil, available from Shell Global of London, England) (“Saraline”) in one sample and the second solvent / diluent was a fatty acid methyl ester (FAME) (e.g., biodiesel) in the final sample (rightmost in Table 3).

[0102] The drilling additive formulations were added into a drilling mud having an organoclay (6.0 g), a hydrocarbon base oil (138 g), amidoamine (8.0 g), a wetting additive (1.5 g), a fluid loss additive based on naturally occurring asphalt (6.0 g), lime (5.0 g), 25% CaCh brine (46.0 g), sepiolite clay (2.0 g), Duramod rheology modifier based on modified fatty acid (1.2 g), and M-I WATE barite (458 g), with a synthetic / water ratio (SWR) of 85.0, a vol (mb) of 349.44, and a Mw (weight in ppg) of 16.01. The mud with the drilling additive formulations was tested for various properties.Attorney Docket No. IS24.1206-WO

[0103] Table 1. Rheology and fluid loss comparison for fatty acid wetting additive (e.g., oleic acid) alone as a reference, and two blends containing the fatty acid wetting additive and a solvent. The first solvent was Saraline, an inert hydrocarbon-based carrier fluid, and the second solvent was biodiesel (e.g., fatty acid methyl ester composition). The hydrocarbon solvent is inert and biodiesel is “active” during use.

[0104] With the “Fatty Acid Wetting additive” blank, 1.5 Ibm / bbl wetting agent was used. In “Fatty Acid Wetting Additive With Saraline,” 1.5 Ibm / bbl of a mixture that consisted of 70% fatty acid (e.g., oleic acid) and Saraline solvent was used. Likewise, in “Fatty Acid Wetting Additive With Biodiesel,” 1.5 Ibm / bbl of a mixture that consisted of 70% fattyAttorney Docket No. IS24.1206-WOacid and biodiesel solvent was used. This was designed to emulate a typical dilution of a wetting agent used to either reduce cost or to improve (e.g., lower) pour point.

[0105] The right column in Table 3 shows what happens when instead of Saraline (e.g., inert hydrocarbon-based oil solvent), “active” diluent biodiesel (e.g., FAME) is used. The benefits of biodiesel include reduced fluid loss compared to other solvents, because biodiesel generates fatty acid by hydrolysis. Fluid loss is comparable to reference “Fatty Acid Wetting Additive” even if initially the “Fatty Acid Wetting Additive With Biodiesel” (rightmost) had less oleic acid present than the “Fatty Acid Wetting additive” blank.

[0106] Additional detail demonstrating that biodiesel is an active ingredient can be observed in low shear rate viscosity values at R3 and R6, and the 10-min gels. Wetting agent reduces the value for these properties. “Fatty Acid Wetting additive” blank shows the lowest values and “Fatty Acid Wetting Additive With biodiesel” is close to those values indicating that biodiesel converted to oleic acid (or comparable fatty acid(s)) during hot roll while a system with “Fatty Acid Wetting Additive With Saraline” shows elevated values for the above-noted properties indicating a lack of wetting agent. This comparison confirms that hydrocarbon solvent is inert, and biodiesel is an “active” and beneficial diluent not only for drilling fluid properties but also for pour points.

[0107] Biodiesel is also biobased and has a low carbon footprint relative to typical hydrocarbon solvents, such as mixtures of alkanes.

[0108] Besides performance in fluids as a wetting agent, it is desirable to formulate the drilling additive formulations disclosed herein for trouble-free wellsite delivery and usage. Various sample drilling additive formulations were tested for pour point and cold temperature performance. The drilling additive formulations included TRUFA OA-3060 (available from Trecento Renewable Chemicals of Dexter, Michigan, U.S.A.), a mixture of fatty acids derived from soybeans including at least about 60% oleic acid. The samples included a blank consisting of only OA-3060, a sample including 70% OA-3060 in a mixture of alkanes (Saraline 185V), and a sample including 70% OA-3060 in a methyl oleate (biodiesel).

[0109] Table 4: Pour Point and comments for blank and samples with alkanes solvent or biodiesel solvent.Attorney Docket No. IS24.1206-WO

[0110] Table 4 shows that pour points achievable with biodiesel are sufficiently low to be trouble-free in low temperature conditions (e.g., at or below -6 °C).[OHl] Further testing was conducted with the second and third sample formulations to determine if wax inhibitor added thereto would influence pour point. The wax inhibitor was Afton HITEC® 5788 (a polymethacrylate commercially available from Afton Chemical of Richmond, Virginia, U.S.A.). The wax inhibitor was 0.3 wt % of the samples, with the OA-3060 remaining at 70 wt %. The presence of the wax inhibitor altered the pour point of the sample with Saraline 185V solvent to -6 °C (compared to -9 °C without the wax inhibitor). The presence of the wax inhibitor did not change the pour point of the sample having methyl oleate (biodiesel) solvent, which remained at -6 °C. Accordingly, a wax inhibitor may be used in an additive composition having fatty acids and biodiesel to inhibit wax formation therein without altering the pour point.

[0112] Further pour point testing was conducted on wetting agent mixtures with a hydrocarbon solvent (e.g., Saraline 185V, a mixture of alkanes) samples and FAME solvent (e.g., biodiesel) samples. The wetting agents included Surewet (an oleic acid based wetting agent) and VDISTILL™ DV53 (a soybean derived fatty acid mixture, available from Vantage Specialty Chemicals of Gurnee, Illinois, U.S.A.). A wax inhibitor (Afton HITEC® 5788) was added to the soybean fatty acid in the FAME.

[0113] Table 5: Additional data on pour points of different fatty acids in either hydrocarbon solvent or biodiesel (methyl oleate).Attorney Docket No. IS24.1206-WO

[0114] Data in Table 5 shows additional comparisons of different fatty acid mixtures for comparison of biodiesel and hydrocarbon oil solvents / diluents. As shown in Table 5, biodiesel is similarly effective to hydrocarbon oil as a diluent but biodiesel, unlike hydrocarbon oil, is an active ingredient (e.g., hydrolyzes to fatty acids). Accordingly, drilling additive formulations may include biodiesel as a solvent or diluent without sacrificing pour point performance.

[0115] The data for the sample with soybean fatty acid in biodiesel with the wax inhibitor shows that using wax inhibitors works to lower the pour point when biodiesel is used. Accordingly, biodiesel does not have disadvantages over hydrocarbon diluents when different drilling additive formulations are formulated.

[0116] In some embodiments, the drilling additive formulations include one or more emulsifiers, such as amidoamine-containing mixtures or the like. For example, biodiesel can be used to dilute 100% (amidoamine) emulsifiers and generate “emulsifier concentrates” in a more efficient manner than diluting emulsifiers with hydrocarbon base oil.

[0117] In some embodiments, the drilling additive formulation may include at least one emulsifier in biodiesel. The one or more emulsifiers may include one or more amidoamines. Suitable amidoamines may include amidoamines made from TOFA, diethylenetriamine (DETA), or maleic anhydrides. The amidoamine(s) may be “high quality” amidoamine(s), such as having a low amine number (e g., amidoamine(s) havingAttorney Docket No. IS24.1206-WOan amine number below about 20 mg KOH / g for a pure amidoamine resin). Such emulsifiers may be disposed in the biodiesel without a base oil.

[0118] The one or more emulsifiers may be at least about 1 wt % of the drilling additive formulation, such as about 1 wt % to about 99 wt %, about 1 wt % to about 25 wt %, about 25 wt % to about 50 wt %, about 25 wt % to about 55 wt %, about 35 wt % to about 45 wt %, about 50 wt % to about 75 wt %, about 75 wt % to about 99 wt %, less than about 99 wt %, less than about 75 wt %, less than about 65 wt %, less than about 50 wt %, or less than about 25 wt % of the drilling additive formulation. For example, the drilling additive formulation may include at least about 10 wt % biodiesel, at least about 25 wt % biodiesel, or at least about 35 wt % biodiesel with at least some of the balance of the formulation being the at least one emulsifier.

[0119] In some embodiments, the one or more emulsifiers may be present alternatively or in addition to one or more fatty acids (e.g., maleated fatty acid). The one or more fatty acids may include any of the fatty acids disclosed herein in any of the amounts disclosed herein.

[0120] Emulsifier additive compositions were tested for viscosity at room temperature. The emulsifier compositions included 65 wt % amidoamine emulsifier in a hydrocarbon base oil solvent / diluent (Saraline 185 V) and a biodiesel solvent / diluent (methyl oleate).

[0121] Table 6: Viscosity and pour point of an emulsifier formulated with base oil compared to the emulsifier formulated in biodiesel.

[0122] The tested samples having 65% amidoamine actives, provide a highly concentrated emulsifier composition. As shown in Table 6, biodiesel has better solvency properties than hydrocarbon base oil without any other additives based on the viscosity of the respective samples. However, example drilling additives with emulsifiers do not preclude using pour point depressants in combination with biodiesel to take advantage of synergies betweenAttorney Docket No. IS24.1206-WObiodiesel solvency and pour point depressant solvency. For example, a drilling additive formulation may include an emulsifier, and a pour point depressant, such as any of the emulsifiers or pour point depressants disclosed herein. In some embodiments, a drilling additive formulation may include one or more of a fluid loss additive, a wetting agent, an emulsifier, a pour point depressant. In some embodiments, the drilling additive formulation may include further additives, such as viscosifiers, rheology modifiers, or any other drilling fluid additive.

[0123] Examples having emulsifiers in combination with pour point depressants in biodiesel solvent provide increased actives concentration without much increase in sample viscosity (e.g., making emulsifier concentrates) and reduce viscosity at low temperatures without relying on excessive pour point additions (maintaining the concentration and pourability of the emulsifier concentrates).

[0124] Adding further chemical components to an emulsifier at a well site can improve emulsifier performance, but determining and implementing the correct mixture of components requires a proper supply of the components and a mud engineer to correctly determine which components and how much of each component need to be added to the emulsifier. Such scenarios demonstrate the difficulty of formulating a drilling additive with an emulsifier for drilling mud.

[0125] Particularly effective drilling additive formulations that include an emulsifier may have a plurality of components, such as a fatty acid composition having one or more maleated fatty acids as disclosed herein, at least one amidoamine, a fatty acid methyl ester (e.g., biodiesel), and at least one glycol (e.g., BTG). For example, drilling additive compositions including an emulsifier may have a fatty acid composition including one or more maleated fatty acids where the maleated fatty acids are about 10 wt% to about 40 wt % (e.g., about 20 wt % to about 30 wt % or about 25 wt %) of the drilling additive formulation, at least one amidoamine resin where the at least one amidoamine resin is about 25 wt % to about 55 wt % (e.g., about 25 wt % to about 45 wt % or about 40 wt %) of the drilling additive formulation, biodiesel (e.g., a fatty acid methyl ester) where the biodiesel is about 10 wt % to 40 wt % (e.g., about 20 wt % to about 30 wt % or about 25 wt %) of the drilling additive formulation, and BTG where the BTG is about 1 wt % to about 20 wt % (e.g., about 5 wt % to about 15 wt %, about 10 wt %, or less than about 15 wt %)Attorney Docket No. IS24.1206-WOof the drilling additive formulation. Such a drilling additive formulation is particularly useful as a universal nonaqueous fluid emulsifier and has demonstrated effectiveness in downhole conditions that cause traditional emulsifiers to break down, such as impractically high viscosity or breakdown from reactions other active components in the drilling additive formulation or brines in a wellbore.

[0126] The universal nonaqueous fluid emulsifier compositions disclosed herein combine one or more amidoamines having a low amine number with at least one maleated fatty acid (e.g., fluid loss control), fatty acid methyl ester (e.g., biodiesel) as a diluent / solvent which converts to fatty acid wetting agent in situ, and a relatively small amount of a glycol (e.g., BTG). This combination of components provides active components in a drilling additive with up to 90% active components while maintaining excellent low temperature handing properties. The universal nonaqueous fluid emulsifier compositions disclosed herein also provide multifunctionality at the well site and downhole in a single, stable mixture.

[0127] The universal nonaqueous fluid emulsifier compositions disclosed herein avoid the use of dimer acids which increase rheology and provide fluid loss control but may result in a need to dilute or thin the composition due to the increased rheology and gelling provided by the dimer acid. The universal nonaqueous fluid emulsifier compositions disclosed herein also avoid using hydrocarbon base oil to dilute the composition, which has a poor solvency, and which may require a relatively large amount of glycol (e.g., more than 10% to 30%) to dissolve the hydrocarbon base oil. Excess glycol can be detrimental to emulsion stability, elastomer stability, mud motor elastomer issues, etc.

[0128] It is particularly difficult to formulate a drilling fluid and continuously treating it with multiple additives without harming the performance of other components in the drilling fluid or additives. For example, conventional emulsifiers may not stabilize emulsions in some conditions and drilling fluids mixtures. Relatively high amounts of amidoamine emulsifiers (e.g., at least 50 wt % or at least 60 wt % amidoamine content) in a drilling fluid have led to instability of the emulsions or may not provide consistent performance under controlled conditions, much less under various downhole conditions.

[0129] Testing of various amidoamine-containing emulsifiers under drilling fluid performance testing was performed as described above with respect to Table 3 and provided a rheology and fluid loss comparison for amidoamine-containing emulsions thatAttorney Docket No. IS24.1206-WOdemonstrated problems with repeatable performance or stability of the emulsion(s) without controlling the amine value of the amidoamine to a sufficiently low number (e.g., about 20 mg KOH / g or less) and adding a fatty acid methyl ester solvent.

[0130] Various universal emulsifier formulations were made to test stability and performance in drilling mud were formed and tested. The respective drilling additives formed as universal emulsifiers included the relative amounts of components shown in Table 7 below. The components included an amidoamine (EMI- 1965 including a fatty acid (C18)-DETA-maleic anhydride composition in 2-1-1 molar ratio available from SLB as RheMax P™), Tenax 2010, BTG, and hydrocarbon oil or FAME (e.g., biodiesel). The relative amounts of the components in each sample are shown in Table 7 below.

[0131] Table 7Attorney Docket No. IS24.1206-WO

[0132] Table 7 demonstrates the importance of the correct formulation and ratios of components in the drilling additive formulation(s). Formulation 1 with 40% EMI- 1965, 20% Tenax 2010, 20% BTG, and 20% hydrocarbon oil had a mediocre performance but did not include the active ingredient FAME, which reacts downhole to form an active ingredient. The hydrocarbon oil merely serves as a diluent for viscosity control. Formulation 2 with 35% EMI-1965, 25% Tenax 2010, 20% BTG, and 20% hydrocarbon oil performed poorer in fluid loss and emulsion stability (as shown by water in filtrate) because the amount of amidoamine (EMI- 1965) was reduced relative to the first formulation. Additionally, Formulation 2 did not include FAME so it contained a relatively lower amount of active ingredients compared to Formulation 3. Formulation 3 included 40% EMI-1965, 25% Tenax 2010, 10% BTG, and 25% FAME (e.g., biodiesel). Formulation 3 performed the best, showing the lowest fluid loss and highest emulsion stability (as demonstrated by the lowest water in the filtrate value).

[0133] The data in Table 7 demonstrates the active ingredients in a formulation should be present in adequate amounts to obtain the best performance of the drilling additive and provide the highest amount of active ingredient per unit volume of the formulation(s). Merely combining active ingredients such as an emulsifier, a fluid loss control agent, and viscosifier without making the formulation too viscous is challenging. The drilling fluid additives including emulsifiers disclosed herein solve this issue by using FAME as a solvent and a fatty acid precursor. Table 7 shows that Formulation 3 performed the best. Formulation 3 also includes 90% active ingredients with only 10% BTG as the diluent / inactive component. Notably, drilling additives with 20% BTG, which are used commercially can destabilize drilling mud. Formulation 3 beneficially reduces BTG to only 10% of the formulation and retains viscosity and pourability while adding more active ingredients to the formulation.

[0134] Selecting an emulsifier with low enough amine value to avoid formation of viscous salts between maleated fatty acids and amidoamine is solved by using the low amine value amidoamine(s) in the drilling additive formulations disclosed herein. FAME (e.g.,Attorney Docket No. IS24.1206-WObiodiesel) solvents or diluents, which are a source of fatty acids and an effective solvent for amidoamines and maleated fatty acid, provides formulations with relatively higher amounts of active ingredients. This relative increase of active ingredients in one formulation or package is important because space at a work site may be saved by including a universal emulsifier formulation than even the individual components of the formulation(s). For example, testing was carried out that demonstrated 7 pounds per barrel (ppb) of the respective samples in the drilling mud was sufficient to maintain a reasonable total volume of universal emulsifier needed in the mud, remove need for additional components, and achieve acceptable performance (e.g., fluid loss control and emulsion stability). Conversely, 7 ppb of a conventional emulsifier in drilling mud needed to be supplemented with 2 ppb of Surewet wetting agent. In the examples in Table 7, emulsifier formulation usage was 7 ppb of the respective samples in the drilling mud to maintain a reasonable total volume of universal emulsifier needed, remove need for additional components, and achieve acceptable performance (e.g., fluid loss control and emulsion stability).

[0135] Further universal emulsifier testing was carried out in different drilling mud formulations. A mud formulation, 220F, included the components disclosed in Table 8 below. A second drilling mud formulation, 285F, included the components shown below in table 9. Among the components of the drilling mud formulations the base oil Biobase 300 (available from Shrieve Chemical of The Woodlands, Texas, U.S.A), an emulsifier blend RheMax P™ (available from SLB of Houston, Texas, U.S.A.), an emulsifier (containing amidoamine, fatty acid, and dimer acid) RheMul (available from SLB), organophilic clay viscosifier VG-SUPREME (available from SLB), VG-PLUS organophilic clay (available from Oceanview Chemical Co. Ltd. from Qingdao, China), VG-69 organophilic clay (available from SLB) is a viscosifier and gelling agent, SUREMUL primary invert-emulsion system emulsifier, and Safe-Carb 10 (available from SLB) is a bridging agent formed from ground marble, G-SEAL PLUS (available from SLB) is a wellbore stabilizing agent, EMI-7001 is a maleated fatty acid, M-I-X II FINE (available from SLB) is a plugging and bridging agent.

[0136] Table 8:Attorney Docket No. IS24.1206-WO

[0137] Table 9:Attorney Docket No. IS24.1206-WO

[0138] Testing of Formulation 1 and Formulation 3 from table 7 in drilling mud Formulation 285F and Formulation 285F was performed as described above with respect to Table 3. The testing provided rheology and fluid loss data as listed in Table 10 below.

[0139] Table 10:

[0140] Table 10 shows performance of the universal NAF emulsifier in additional formulations to show that the emulsifier formulations works in many different systems.Attorney Docket No. IS24.1206-WOTable 10 shows Formulation 1 details which controlled fluid loss but not as well as Formulation 3. Universal emulsifier of Formulation 3 (providing 90% actives) performed very well. Formulation VI showed some limitations likely due to insufficient active ingredients. In either case, instead of using 3 separate additives as shown in the 220F formulation in Table 10, it is simpler and easier to just add more of the universal emulsifier of Formulation 1 even if it did not perform as well as Formulation 3.

[0141] Table 10 shows performance of the universal NAF emulsifier in additional formulations to show that emulsifier works in many different systems. Table 10 shows the Formulation 1 did not control fluid loss as well as Formulation 3.

[0142] Subsequent to the testing carried out according to Table 10, the mud formulation for Formulation 220F was changed to remove Rhemax P, Surewet, and Novatec F, while only 10 ppb of universal emulsifier of Formulation 1 and Formulation 3 were used. Likewise, mud Formulation 285F, containing diesel, was reformulated to remove Rhemax P and EMI-7001, while only 6 ppb of universal emulsifier Formulation 1 or Formulation 3 were used in the drilling mud formulation 285F.

[0143] The same testing carried out with respect to Table 10 was carried out with the new formulations of Formulation 220F and 285F with currently available emulsifiers Suremul (available from SLB) and Rhemul (available from SLB), separately. The testing showed fluid loss at unacceptably high levels (10.6 and 9.2 ml / 30 min.) with the respective emulsifiers Suremul and Rhemul and instability with water in the filtrate of 0.6 and 0.8 ml for Suremul and Rhemul, respectively. Accordingly, even drilling mud with biodiesel combined with commercially available emulsifiers does not perform as well as the universal emulsifier formulations disclosed herein.

[0144] Further testing demonstrated that simply changing the emulsifier used with various drilling fluids does not prevent fluid loss or provide a stable emulsion compared to the universal emulsifiers disclosed herein.

[0145] A drilling mud formulation, Formulation 301, included 151.38 ppb of Escaid 110 hydrocarbon base oil (available from ExxonMobil Chemical of Spring, Texas, U.S.A.), 5.5 ppb of VG-SUPREME organophilic clay viscosifier, 7 ppb of Suremul Plus emulsifier, 1 ppb of Surewet wetting agent, 1 ppb of lime, 80.1 ppb of water, 32.92 ppb of 95% CaCh, 60 ppb of SafeCarb 2 (available from SLB), 60 ppb of SafeCarb 20 (available from SLB),Attorney Docket No. IS24.1206-WO60 ppb of SafeCarb 40 (available from SLB), and 35 ppb of API standard evaluation clay. The Formulation 301 was used to perform 300 °F hot roll and HPHT testing according to the testing procedures described above with respect to Table 3 at 300 °F. The testing was carried out with Formulation 301 including the amounts and types of additives indicated in Table 11. For example, various amounts and types of emulsifiers or additives that effect emulsification are added to Formulation 301 to form test samples A-D. Sample A includes a total of 3 ppb of Surewet wetting agent. Sample B includes EMI- 1965 amidoamine additive instead of Suremul Plus. Sample C includes EMI- 1965 amidoamine additive and 3 ppb SUREWET total. Sample D includes the universal emulsifier according to Formulation 3 disclosed above. The results of the tests of Samples A-D are shown below in Table 11.

[0146] Table 11 :

[0147] As shown, Sample D greatly outperformed Samples A-C in both fluid loss after 10 and 30 minutes in combination with water in fluid or filtrate (WIF) performance that exceeded Samples A-C by at least an order of magnitude.Attorney Docket No. IS24.1206-WO

[0148] These results in Table 11 show that changing the emulsifier alone does not resolve the fluid loss and stability issues of emulsifiers as indicated by a large total filtrate volume and significant amount of water in the filtrate of Samples A-C. Similarly, addition of a wetting agent, Surewet, does not solve the above-noted issues. The issue can be resolved by adding 10 ppb of Formulation 3. The universal emulsifier of Formulation 3 may be used instead of 5 ppb of Novatek F or EMI-7001 (maleated fatty acid), 7 ppb Suremul plus, and 1 ppb Surewet. The material savings is 3 ppb of additives in this case. While the results still show a small amount of water in the filtrate, the results are a substantial improvement over other emulsifiers and / or emulsifiers in combination with wetting agent.

[0149] Another benefit of the universal emulsifiers disclosed herein is low potential for formation damage. Fluid loss can be controlled by including fluid loss control polymers. Examples are gilsonite, asphaltic materials, or synthetic products like Ecotrol RD, HT, and the like. These synthetic products can cause formation damage if the nonaqueous fluid is used to drill reservoir sections. The components present in the universal emulsifiers disclosed herein are not formation damaging.

[0150] Return permeability test results of Formulation 3 demonstrated a high value for the return permeability showing the components of the universal emulsifier compositions disclosed herein are not formation damaging even when used in relatively high amounts. The results showed a return permeability of 83% compared to initial permeability.

[0151] Based on the foregoing, the universal emulsifiers in this disclosure provide numerous advantages over currently available emulsifiers and even over the individual components of the universal emulsifiers, without sacrificing performance in other aspects.

[0152]

[0153] The inventors have discovered that commercially available fluid loss control additives do not perform consistently despite having components expected to perform in a certain manner. After performance testing various fluid loss control products, it was observed that not all products perform as expected. The reported acid value specifications from various fluid loss additives indicated acid values of greater than 300mgKOH / g which indicates a high degree of maleation, yet performance was not the same for all of these additives. For reference, unmaleated C18 fatty acid has an acid value of about 190— 200 mgKOH / g.Attorney Docket No. IS24.1206-WO

[0154] By adding water and affecting hydrolysis of the maleic anhydride moiety in the maleated fatty acids, the performance of the fluid loss control additives is improved without imparting any additional handling or formulation issues. Hydrolysis can be achieved in a nonaqueous fluid (NAF) formulation and performance improves while maintaining all the benefits of the nonaqueous product formulations.

[0155] By adding a maleated fatty acid to a NAF, fluid loss control is expected to improve. However, while the key performance specifications, like acid value, for all products was similar, there were apparently structural differences in the chemicals that are not accounted for in the specifications of theses additives. While such structural differences are not accounted for, they become apparent upon testing, such as chemical and rheological testing.

[0156] Samples were made of a drilling mud formulation. One of three maleated fatty acid fluid loss control compositions was added to the samples of drilling mud. Four pounds per barrel of Tenax 2010, MTO 85 (available from SumiSaujana TCM Chemicals of Malaysia), and Sterdrill 7010 (available from Sterling Specialty Chemicals of Houston, Texas, U.S.A.) were added to three respective samples of the drilling mud. The samples were tested for rheological properties and fluid loss properties. The sample with Tenax 2010 performed the best on fluid loss control, with the samples containing MTO 85 and Sterdrill 7010 showing inferior results to the sample with Tenax 2010.

[0157] Fourier transform infrared (FTIR) testing was carried out on Tenax 2010, MTO 85, and Sterdrill 7010. The FTIR spectra showed a peak at about 1780 cm'1for Tenax 2010 that was lower than the corresponding peak for MTO 85 and Sterdrill 7010. FIG. 5 depicts FTIR spectra of Tenax 2010, MTO 85, and Sterdrill 7010 prior to hydrolysis. The peaks at about 1780 cm'1for MTO 85 and Sterdrill 7010 had absorbance values that were nearly two times larger than the absorbance value for Tenax 2010. As noted above, Tenax 2010 performed the best in fluid loss control testing.

[0158] The ability of maleic anhydride to undergo reversible ring opening or closing depending on temperature and presence of water provides variation in the effectiveness / functionality of maleic anhydride-containing compositions. For example, in FIG. 6, we see a difference in spectra from treating the maleic anhydride-containing composition with water prior to use in a drilling mud. Hydrolyzing the maleic anhydrideAttorney Docket No. IS24.1206-WOcomposition with a relatively small amount of water (e.g., less than 2 wt% or about 1 wt %) produces a drastically different chemical spectra for the same composition, which indicates hydrolysis upon exposure to water.

[0159] FTIR spectra was collected for a sample of Sterdrill 7010 before and after treatment with an aqueous solution of 0.5NNaOH. FIG. 6 is an FTIR spectra of Sterdrill 7010 before and after hydrolysis with water. As shown, the peak at about 1780 cm’1was drastically reduced by hydrolysis with 0.5NNaOH solution. Based on the difference in spectra arising from pre-treatment with water, the maleic ring in the maleated fatty acid is believed to be hydrolyzed from an unhydrolyzed state.

[0160] Similar results were achieved with MTO 85 and Tenax 2010. FIG. 7 depicts FTIR spectra of Tenax 2010, MTO85, and Sterdrill 7010 after hydrolysis with water. As shown, in FIG. 7, the FTIR spectra of the three samples show similar peaks at about 1780 cm’1after pretreatment with water, demonstrating the maleic ring in the maleated fatty acids of the samples is now hydrolyzed.

[0161] Rheological performance of Tenax 2010 was used as a reference against other drilling fluid additives since it appears to be the most hydrolyzed out of the package. Novatec F is a current commercial drilling fluid additive with lower effectiveness than the embodiments disclosed herein. Tenax 2010, Novatec F, Sterdrill 7010, and MTO 85 were tested in drilling mud for rheological and fluid loss properties at 150 °F according to the testing procedures disclosed above with respect to Table 3. The various samples were tested as fluid loss control additives in a drilling mud composition including 147.54 ppb Escaid 110, 6 ppb Versagel HT viscosifier (available from SLB), 3 ppb lime, 8 ppb One-Mul emulsifier (available from SLB), 32.63 ppb water, 11.45 ppb CaCk dry salt, 25 ppb Ocma clay, and 438.38 ppb M-I Wate. The sample fluid loss control agents were added to the drilling mud to provide about 4 ppb of the fluid loss control agents. All blends of the fluid loss control agents were 60% maleated fatty acid with 40% fatty acid methyl ester (FAME). The testing took place after hot rolling (AHR) of the samples. The test results showed that the rheology of the samples was not affected to a large extent by the different maleated fatty acid-containing fluid loss control agents. Rheology performance of the different fluid loss control additives was generally similar across the various samples, but there was a difference in HPHT fluid loss performance. Table 13 below shows the fluidAttorney Docket No. IS24.1206-WOloss results of Sterdrill 7010 blend with FAME in both unhydrolyzed and hydrolyzed (after pretreatment of the blend with a small amount of water) states as well as an MTO 85 blend with FAME in both unhydrolyzed and hydrolyzed states.

[0162] Table 13:

[0163] As-is Sterdrill 7010 fluid loss performance was inferior to Tenax 2010 (exhibiting about 6.8 ml fluid loss at 350 °F HPHT testing), but after hydrolysis the fluid loss control performance was similar. While MTO 85 fluid loss performance lagged relative to Tenax 2010, hydrolysis of MTO 85 improved the fluid loss control performance of MTO 85. The trend with hydrolysis pretreatment of maleated fatty acid components is improved performance compared to the corresponding as-is (e.g., unhydrolyzed) components.

[0164] While it may be expected that the anhydride moiety in maleated fatty acid should hydrolyze eventually when added to NAF and drilling mud, the water is locked in the internal phase of the NAF and when using highly effective emulsifiers, water may not become readily available for hydrolysis of the anhydride moiety. Furthermore, an anhydride moiety can react with oil soluble amines of amidoamine emulsifier systems because such oil soluble amines always have some unreacted intermediates. If a maleated acid fluid loss control agents react with an amine, an amide is formed that is highly oil soluble and may no longer hydrolyze. This amide formation could cause a performance difference as observed in Table 13 for as-is versus hydrolyzed fluid loss control agents even when it would be expected that the anhydride would hydrolyze readily. Accordingly, intentional hydrolysis of the anhydride moiety prior to mixing with a drilling fluid provides performance benefits to fluid loss control agents including anhydride moieties, such as maleated fatty acids.

[0165] Such hydrolysis may be carried out by adding a relatively small amount of water or an aqueous solution to the fluid loss control agent (e.g., maleated fatty acid) and fatty acid methyl ester (e.g., biodiesel) blend prior to addition of the blend to the NAF (e.g.,Attorney Docket No. IS24.1206-WOdrilling fluid or drilling mud). For example, the water or aqueous solution may be less than 2 wt % of the blend, such as about 0.01 wt % to about 2 wt %, about 0.5 wt % to about 1.5 wt%, about 0.1 wt% to about 1 wt%, less than about 1 wt% or more than about 0.1 wt % of the blend. In some embodiments, the water or aqueous solution may include a salt solution, such as sodium hydroxide (0.5N), calcium chloride, potassium hydroxide, or the like.

[0166] After hydrolysis, the water may remain in the blend or may be removed from the blend, such as by evaporation. After hydrolysis, the blend may include “fully” or “highly” hydrolyzed maleated fatty acids (e.g., at least 50%, at least 80%, at least 90%, at least 95%, at least 99%, or at least 99.99% of anhydride moieties of the maleated fatty acids are hydrolyzed).

[0167] The fluid loss control agents including hydrolyzed maleated fatty acids provide advantages over conventional fluid loss control agents and even fluid loss control agents having unhydrolyzed maleated fatty acids for nonaqueous fluids. For example, additional testing showed maleated fatty acid fluid loss control agents performed better than dimer acid fluid loss control agents in total fluid loss tests and rheological properties such as 3 and 6 rpm rheology tests. For example, addition of a rheology modifier based on dimer acid like Suremod removed water in the filtrate but total fluid loss was higher with Suremod, 3 / 6 rpm rheology results were much higher (likely too high), and 10-minute gels were elevated. This shows that maleated fatty acids and blends are good fluid loss control agents and hydrolysis of anhydride moiety increases the performance of these compositions.

[0168] The biodiesel-containing drilling fluid compositions disclosed herein provide for higher actives concentrations in drilling additive formulations. The higher actives concentrations provide for a more active-dense, longer lasting additive supply. Such embodiments may reduce the footprint needed for drilling additives at a drill site and may provide for longer use (e.g., less switching of supplies) at well sites.

[0169] In some embodiments, the drilling additive formulations disclosed herein may be preformed or may be formed on site. The drilling additive formulation(s) disclosed herein may be added to a drilling fluid to form modified drilling fluid(s) containing a selected amount of the drilling additive formulation(s).Attorney Docket No. IS24.1206-WO

[0170] FIG. 3 is a flow chart of a method 300 of forming a drilling additive formulation, according to at least some embodiments. The method 300 of forming a drilling additive formulation, includes an act 310 of providing a fatty acid composition and an act 320 of mixing a biodiesel with the fatty acid composition to form the drilling additive formulation, wherein the biodiesel is less than 50 wt % of the drilling additive formulation. The method 300 may include more or fewer acts than the acts 310-320. For example, any of the acts 310 or 320 may be combined, split into separate acts, or omitted. Additional acts may be included in the method 300.

[0171] The act 310 of providing a fatty acid composition may include providing any of the fatty acids or fatty acid compositions disclosed herein. For example, providing a fatty acid composition may include providing at least one C8 to C22 saturated, monounsaturated, or polyunsaturated fatty acid; at least one maleated fatty acid; or combinations thereof. The at least one fatty acid may include one or more of oleic acid, linoleic acid, linolenic acid, or stearidonic acid.

[0172] In some embodiments, the fatty acid composition may include at least one C8 to C20 or CIO to C20 saturated, monounsaturated, or polyunsaturated fatty acid. The amount of saturated fatty acid to mono or polyunsaturated fatty acid may include any of the ratios disclosed herein.

[0173] In some embodiments, the at least one fatty acid composition may include at least one maleated fatty acid. For example, the maleated fatty acid(s) may include the maleated form of any of the unsaturated fatty acids disclosed herein, such as maleated internal mono-or polyunsaturated C12-C20 fatty acids. The at least one maleated fatty acid may include maleated tall oil fatty acid (TOFA). Generally, maleated fatty acids to have a higher acid number than the base fatty acid (e.g., the same nonmaleated fatty acid). Accordingly, the fatty acid composition and resulting drilling additive formulation may have a relatively higher acid number when maleated fatty acids are present.

[0174] In some embodiments, the maleated fatty acid may be a hydrolyzed maleated fatty acid, such as having been hydrolyzed by water or an aqueous solution prior to, contemporaneously with, or after adding the maleated fatty acid to the fatty acid methyl ester (e g., biodiesel). Such hydrolysis may include using less than 2 wt % water in a blend of at least biodiesel and maleated fatty acid.Attorney Docket No. IS24.1206-WO

[0175] In some embodiments, the at least one fatty acid does not include fatty acid(s) derived from TOFA. In such examples, the at least one fatty acid may be vegetable or animal derived. In some embodiments, the at least one fatty acid may be synthetic, including one or more components (e.g., esters) created from petrochemical source material(s).

[0176] In some embodiments, at least one amidoamine may be used in place of or in addition to the at least one fatty acid, such as any of the amidoamines disclosed herein. In such examples, the biodiesel may be combined with the at least one amidoamine to form the drilling additive formulation.

[0177] The fatty acid composition may be combined with a solvent to form the drilling additive formulation. As disclosed herein biodiesel or fatty acid methyl esters provide numerous benefits without sacrificing efficacy of the fatty acid composition during storage, at a well site, or during use.

[0178] The act 320 of mixing a biodiesel with the fatty acid composition to form the drilling additive formulation may include using any of the biodiesels disclosed herein. For example, the biodiesel may include one or more of C18 monounsaturated fatty acid methyl esters, polyunsaturated fatty acid methyl esters, C16 saturated methyl esters, or Cl 8 saturated methyl esters. In some embodiments, the biodiesel may include biodiesel fitting the ASTM definition of biodiesel noted above. In some embodiments, the biodiesel may include “failed” or “off spec” biodiesel having a combination of methyl esters, fatty acids, and possibly some glycerin. In some embodiments, the biodiesel may include FAMEs other than those derived from tall oil fatty acids. In some embodiments, the biodiesel is free of FAME derived from tall oil fatty acids.

[0179] Mixing a biodiesel with the fatty acid composition may include adding, pouring, titrating, or otherwise combining the biodiesel with the fatty acid composition. In some embodiments, mixing a biodiesel with the fatty acid composition may include stirring, bubbling, agitating, or otherwise moving the components of the drilling additive formulation to form a substantially uniform mixture, emulsion, solution, or the like.

[0180] The acts 310 and 320 are performed effective to provide the drilling additive formulation wherein the biodiesel is less than 50 wt % of the drilling additive formulation. For example, the drilling additive formulation may include at least 60 wt% fatty acidAttorney Docket No. IS24.1206-WOcomposition (e.g., one or more fatty acids) and less than about 50 wt% biodiesel (e.g., FAME). In some embodiments, providing a fatty acid composition may include providing the fatty acid composition in an amount selected to result in any of the drilling additive formulations disclosed herein, such as having a drilling additive formulation with at least 5 wt %, at least 50 wt %, or at least 60 wt % fatty acid composition. In some embodiments, mixing a biodiesel with the fatty acid composition to form the drilling additive formulation may include providing and / or mixing the biodiesel in an amount selected to result in any of the drilling additive formulations disclosed herein, such as a drilling additive formulation having less than about 90 wt %, less than about 80 wt %, less than about 50 wt %, less than about 40 wt%, or less than about 30wt% biodiesel. Any of the proportions of fatty acid(s) and biodiesel disclosed herein may be present in the drilling additive formulation formed by the method 300.

[0181] In some embodiments, the method may include adding one or more additives to the drilling additive formulation or drilling fluid composition, such as one or more of an emulsifier, a fluid loss additive, a wetting agent, a viscosifier, a rheology modifier, or the like. For example, the method 300 may further include mixing an emulsifier with the fatty acid composition and biodiesel. In such examples, the emulsifier may include at least one amidoamine, such as any of the amidoamines disclosed herein. The at least one amidoamine may be at least 1 wt % of the drilling additive formulation (e.g., 1 wt % to 55 wt %). In some embodiments, the method 300 may include adding at least one glycol (e.g., BDG or BTG) to the emulsifier with the fatty acid composition and biodiesel. In such examples, the at least one glycol may be less than 20 wt % of the drilling additive formulation, such as less than about 15 wt% or less than about 10 wt % of the drilling additive formulation.

[0182] In some embodiments, the method 300 may include hydrolyzing the maleic anhydride moieties in the maleated fatty acid(s). In such embodiments, the hydrolysis may be carried out prior to, contemporaneously with, or after combining the maleated fatty acid of the fatty acid composition with the biodiesel (or other fatty acid methyl ester). The hydrolysis may be carried out by adding less than about 2 wt % water to the mixture of the fatty acid composition and the biodiesel, such as less than about 1 wt % water. The water may be added in about a 1 : 1 molar ratio with the maleic anhydride moieties of the maleatedAttorney Docket No. IS24.1206-WOfatty acids; in slight molar excess, such as 1.5:1; or even a slight molar deficit, such as 0.5:1. The molar ratio of water to maleic anhydride moieties in the maleated fatty acids may range below, above, or between any of the values listed above.

[0183] In some embodiments, after hydrolysis of the anhydride moieties in the blend or drilling additive composition, the water may be removed from the blend of drilling additive composition, such as through heating, evaporation, or the like.

[0184] The method 300 may include forming the drilling additive formulation effective to provide a pour point of about -0 °C or less, or about -6 °C or less for the drilling additive formulation.

[0185] In some embodiments, the method 300 may include placing the drilling additive in a storage container, such as a tank, a drum, a barrel, a bottle, a bucket, or the like. In some embodiments, the drilling additive formulation may be stored prior to use.

[0186] In some embodiments, the method 300 may include combining any of the additives disclosed herein with the at least one fatty acid composition, the biodiesel, or the drilling additive formulation. The additives may include an emulsifier, a wetting agent, a corrosion inhibitor, a wax inhibitor, a fluid loss additive, a viscosifier, a pour point depressant, or any other additive disclosed herein.

[0187] The drilling additive formulations formed according to the methods disclosed herein may be used to perform one or more functions in drilling fluid upon mixing therewith.

[0188] Fig. 4 is a flow chart of a method 400 of forming a borehole extending through an earth formation, according to at least some embodiments. The method 400 forming a borehole extending through an earth formation includes an act 410 of mixing a drilling additive formulation with a drilling fluid, the drilling additive formulation including a fatty acid composition and a biodiesel, and an act 420 pumping the drilling fluid including the drilling additive formulation into the earth formation. The method 400 may include more or fewer acts than the acts 410-420. For example, any of the acts 410 or 420 may be combined, split into separate acts, or omitted. Additional acts may be included in the method 400.

[0189] The act 410 of mixing a drilling additive formulation with a drilling fluid may include using any of the drilling additive formulations disclosed herein, such as a mixtureAttorney Docket No. IS24.1206-WOof a fatty acid composition and a biodiesel. The fatty acid composition may include any of the fatty acids disclosed herein, such as at least one C8 to C22 saturated, monounsaturated, or polyunsaturated fatty acid; at least one maleated fatty acid; or combinations thereof. For example, the fatty acid composition may include at least one C8 to C20 or CIO to C20 saturated, monounsaturated, or polyunsaturated fatty acid. The amount of saturated fatty acid to mono or polyunsaturated fatty acid may include any of the ratios disclosed herein. Mixing drilling additive formulation with a drilling fluid may include mixing the drilling additive formulation including less than about 50 wt % biodiesel, with the drilling fluid.

[0190] In some embodiments, at least one amidoamine may be used in place of, or in addition to, the at least one fatty acid, such as any of the amidoamines disclosed herein. In such examples, the biodiesel may be combined with the at least one amidoamine to form the drilling additive formulation.

[0191] The drilling fluid may include any of the drilling fluids disclosed herein, such as an aqueous-based drilling fluid or a nonaqueous-based drilling fluid. The drilling additive formulations disclosed herein may include only nonaqueous fluids. The drilling fluid may include a drilling mud. Mixing a drilling additive formulation with a drilling fluid may include feeding the drilling additive formulation into the drilling fluid in a drilling fluid (mud) pond. Mixing a drilling additive formulation with a drilling fluid may include flowing the drilling additive formulation from a drum, a barrel, a bucket, a bottle, or other container, into the drilling fluid. Such mixing may include adding the drilling fluid additive in a continuous feed or by addition of an entire container of the drilling additive formulation in a single pour. In some embodiments, the continuous feed may be a titration or paced drop wise addition of the drilling additive formulation into the drilling mud.

[0192] The drilling additive formulation may be fed at a selected rate to achieve and maintain a selected concentration of the drilling additive formulation in the drilling fluid. For example, mixing a drilling additive formulation with a drilling fluid includes adding the drilling additive formulation into the drilling fluid effective to form a drilling fluid having 15 Ibm / bbl or less of the drilling additive formulation or components thereof. After mixing, the drilling additive formulation or a component thereof may be present in a concentration of about 1 Ibm / bbl to about 500 Ibm / bbl in the drilling fluid, such as about 1 Ibm / bbl to about 100 Ibm / bbl, about 100 Ibm / bbl to about 200 Ibm / bbl, about 200 Ibm / bblAttorney Docket No. IS24.1206-WOto about 300 Ibm / bbl, greater than 0 Ibm / bbl to about 25 Ibm / bbl, about 1 Ibm / bbl to about 15 Ibm / bbl, about 1 Ibm / bbl to about 5 Ibm / bbl, about 5 Ibm / bbl to about 10 Ibm / bbl, about 10 Ibm / bbl to about 15 Ibm / bbl, about 1 Ibm / bbl to about 50 Ibm / bbl, about 10 Ibm / bbl to about 40 Ibm / bbl, about 50 Ibm / bbl to about 100 Ibm / bbl, more than about 1 Ibm / bbl, more than about 10 Ibm / bbl, less than about 250 Ibm / bbl, less than about 100 Ibm / bbl, less than about 50 Ibm / bbl, less than about 25 Ibm / bbl, or less than about 15 Ibm / bbl.

[0193] The act 420 pumping the drilling fluid including the drilling additive formulation into the earth formation may include pumping any of the drilling fluids having any of the drilling additive formulations disclosed herein. The act 420 of pumping the drilling fluid may include pumping the drilling fluid into, or through, a drill pipe or borehole, such as from the surface.

[0194] The act 420 of pumping the drilling fluid may include forming a borehole in the earth formation before, while, or after pumping the drilling fluid including the drilling additive formulation into the earth formation. Forming the borehole may include drilling the borehole in the earth formation using any of the drilling techniques and equipment disclosed herein, while pumping the drilling fluid into the earth formation, such as into the borehole. For example, forming the borehole may include drilling. The method 400 may include circulating the drilling fluid within the borehole.

[0195] The act 420 of pumping the drilling fluid may include discharging the drilling fluid from one or more selected-size nozzles, jets, or other orifices in a drill bit, such as for one or more of cooling the drill bit, for cutting structures thereon, or for lifting cuttings out of the borehole or wellbore as it is being drilled.

[0196] The method 400 may include adjusting the amount of the drilling additive formulation pumped from a first amount to a second amount. For example, the adjustment may be from a lower concentration to a higher concentration of the drilling additive formulation or vice versa. Such adjustments may be based on one or more of downhole fluid composition, well fluid composition, drilling fluid composition, or the like over time, such as when changes in the foregoing are detected over time.

[0197] In some embodiments, the method 400 includes forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid. For example, as the biodiesel hydrolyzes in the drilling mud from a reaction with water therein,Attorney Docket No. IS24.1206-WOadditional fatty acids are formed as products, and the additional fatty acids may perform one or more beneficial functions within the drilling fluid, such as wetting, fluid loss control, or the like. Accordingly, the biodiesel performs as an “active” component within the drilling fluid in situ.

[0198] In some embodiments, one or more of the acts 410 or 420 may include forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid and earth formation (e.g., borehole therein). In some embodiments, pumping the drilling fluid including the drilling additive into the earth formation may include forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid. Likewise, mixing a drilling additive formulation with a drilling fluid may include forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid. Forming (e g., drilling) the borehole in the earth formation may include forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid.

[0199] While amounts of fluid components are disclosed herein in pounds per barrel (ppb), the pounds per barrel amounts may be expressed in kg / m3by multiplying the amount in ppb by 2.85 kg / m3.

[0200] The embodiments of wellbore (e.g., drilling) fluids including the NAF compositions have been primarily described with reference to wellbore drilling operations; the drilling additive formulations and drilling fluids described herein may be used in applications other than the drilling of a wellbore or borehole. In some embodiments, wellbore fluids including the NAF composition according to the present disclosure may be used outside a wellbore, borehole, or other downhole environment used for the exploration or production of natural resources. Accordingly, the terms “wellbore,” “borehole,” and the like should not be interpreted to limit tools, systems, assemblies, or methods of the present disclosure to any particular industry, field, or environment. In addition, the drilling fluids may be used in cased completion wellbores and in open hole completion wellbores.

[0201] In some embodiments, the drilling fluids may be used during formation of a borehole and / or wellbore to be used for carbon capture, utilization, and storage (CCUS) and / or for recovery and use of geothermal energy. For example, the drilling fluids may beAttorney Docket No. IS24.1206-WOused to form boreholes and / or wellbores without introducing materials to the earth formation that may impede subsequent storage of carbon in the earth formation.

[0202] Geothermal energy is a promising source of renewable energy that captures energy from heat generated within the earth. For example, geothermal energy may be used to heat structures (e.g., buildings) and / or to generate electricity (e.g., by heating water to generate steam and drive a turbine with the steam). The drilling fluids described herein may be used to form boreholes and / or wellbores used to circulate a fluid that is heated within the earth formation through which the borehole and / or wellbore extends. The heated fluid may be circulated to the surface where the captured heat may be recovered to heat a structure and / or generate electricity, followed by recirculation of the fluid to the earth formation to continue the cycle.

[0203] CCUS facilitates the capture, use, and / or storage of carbon (e.g., carbon dioxide), which has a goal of achieving carbon neutrality and / or net zero carbon emissions (NZE). CCUS may facilitate the capture of carbon dioxide from large point sources (e.g., power plants, refineries, cement plants, other industrial processing plants, or other industrial facilities that use fossil fuels, biomass fuels, or other fuels that generate carbon dioxide). The captured carbon dioxide may be converted into valuable products such as, for example, ethanol, sustainable aviation fuel, chemicals, and mineral aggregates. Alternatively, the carbon dioxide may be stored in geologic formations, such as in depleted hydrocarbon reservoirs. The carbon dioxide may be introduced into the earth formation through a borehole and / or wellbore formed using the drilling fluids described herein. In the earth formation, the carbon dioxide may be dispersed in an aqueous phase and stored as carbon dioxide, in mineral form (e.g., as a carbonate, such as calcium carbonate, magnesium carbonate, iron(II) carbonate), or as another form of carbon.

[0204] One or more specific embodiments of the present disclosure are described herein. These described embodiments are examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, not all features of an actual embodiment may be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous embodiment-specific decisions will be made to achieve the developers’ specific goals, such as compliance with system-related andAttorney Docket No. IS24.1206-WObusiness-related constraints, which may vary from one embodiment to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0205] The articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements in the preceding descriptions. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, any element described in relation to an embodiment herein may be combinable with any element of any other embodiment described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by embodiments of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value.

[0206] A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to embodiments disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition,Attorney Docket No. IS24.1206-WOdeletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims.

Claims

1. Attorney Docket No. IS24.1206-WOCLAIMSWhat is claimed is:

1. A drilling additive formulation of nonaqueous fluids, the formulation comprising:a fatty acid composition; anda biodiesel, wherein the biodiesel is less than 90 weight percent (wt %) of the drilling additive formulation.

2. The drilling additive formulation of claim 1, wherein the biodiesel includes one or more of Cl 8 monounsaturated fatty acid methyl esters, polyunsaturated fatty acid methyl esters, C16 saturated methyl esters, or Cl 8 saturated methyl esters.

3. The drilling additive formulation of claim 1, wherein the fatty acid composition includes a maleated fatty acid.

4. The drilling additive formulation of claim 3, wherein the maleated fatty acid includes maleated tall oil fatty acid (TOFA).

5. The drilling additive formulation of claim 3, wherein the maleated fatty acid includes a hydrolyzed maleated fatty acid.

6. The drilling additive formulation of claim 3, wherein the maleated fatty acid is 90 wt % or less of the drilling additive formulation and the biodiesel is less than 40 wt % of the drilling additive formulation.

7. The drilling additive formulation of claim 6, further comprising water, wherein the drilling additive formulation is less than 2 wt % water.

8. The drilling additive formulation of claim 1, wherein:the fatty acid composition includes at least one C8 to C20 saturated, monounsaturated, or polyunsaturated fatty acid; andthe biodiesel is less than 50 wt % of the drilling additive formulation.

9. The drilling additive formulation of claim 8, wherein the fatty acid composition includes one or more of oleic acid, linoleic acid, linolenic acid, or stearidonic acid.

10. The drilling additive formulation of claim 8, wherein the drilling additive formulation has a pour point of about -6 °C or less.

11. The drilling additive formulation of claim 8, further comprising a wax inhibitor.

12. The drilling additive formulation of claim 1, further comprising an emulsifier.Attorney Docket No. IS24.1206-WO13. The drilling additive formulation of claim 12, wherein the emulsifier includes at least one amidoamine.

14. The drilling additive formulation of claim 12, wherein the biodiesel is at least 35 wt % of the drilling additive formulation.

15. The drilling additive formulation of claim 1, wherein the fatty acid composition includes one or more maleated fatty acids, wherein the one or more maleated fatty acids are about 10 wt % to about 40 wt % of the drilling additive formulation and the biodiesel is about 10 wt % to 40 wt% of the drilling additive formulation, the drilling additive formulation further comprising:at least one amidoamine resin, wherein the at least one amidoamine resin is about 25 wt % to about 55 wt % of the drilling additive formulation; andbutoxytri glycol, wherein the butoxytriglycol is about 1 wt % to about 20 wt % of the drilling additive formulation.

16. The drilling additive formulation of claim 15, wherein:the one or more maleated fatty acids are about 20 wt % to about 30 wt % of the drilling additive formulation;the at least one amidoamine resin is about 35 wt % to about 45 wt % of the drilling additive formulation;the biodiesel is about 20 wt % to 30 wt % of the drilling additive formulation; and the butoxytri glycol is about 10 wt % or less of the drilling additive formulation.

17. A method of forming a drilling additive formulation, the method comprising: providing a fatty acid composition; andmixing a biodiesel with the fatty acid composition to form the drilling additive formulation;wherein the biodiesel is less than 90 weight percent (wt %) of the drilling additive formulation.

18. The method of claim 17, wherein:providing a fatty acid composition includes providing a maleated fatty acid; and the maleated fatty acid is 90 weight percent (wt %) or less of the drilling additive formulation and the biodiesel is less than 50 wt % of the drilling additive formulation.Attorney Docket No. IS24.1206-WO19. The method of claim 18, further comprising hydrolyzing the maleated fatty acid effective to hydrolyze maleic anhydride moieties present in the maleated fatty acid.

20. The method of claim 19, wherein hydrolyzing the maleated fatty acid includes adding water to the drilling additive formulation, wherein the water is less than about 2 wt % of the drilling additive formulation.

21. The method of claim 17, wherein:the fatty acid composition includes at least one C8 to C20 saturated, monounsaturated, or polyunsaturated fatty acid; andthe drilling additive formulation has a pour point of about -6 °C or less.

22. The method of claim 17, further comprising mixing an emulsifier with the drilling additive formulation, wherein the emulsifier includes at least one amidoamine.

23. The method of claim 22, further comprising mixing at least one glycol into the drilling additive formulation, the at least one glycol including one or more of butoxytriglycol or butoxy di glycol.

24. The method of claim 17, further comprising mixing at least one amidoamine and butoxytri glycol into the drilling additive formulation, wherein:the fatty acid composition includes one or more maleated fatty acids that are about 20 wt % to about 30 wt % of the drilling additive formulation;the at least one amidoamine is about 35 wt% to about 45 wt % of the drilling additive formulation;the biodiesel is about 20 wt % to 30 wt % of the drilling additive formulation; and the butoxytriglycol is about 5 wt % to about 15 wt% of the drilling additive formulation.

25. A method of forming a borehole extending through an earth formation, the method comprising:mixing a drilling additive formulation with a drilling fluid, the drilling additive formulation including a fatty acid composition and a biodiesel; andpumping the drilling fluid including the drilling additive formulation into the earth formation.Attorney Docket No. IS24.1206-WO26. The method of claim 25, wherein mixing a drilling additive formulation with a drilling fluid includes mixing the drilling additive formulation including less than about 90 weight percent (wt %) of the biodiesel, with the drilling fluid.

27. The method of claim 25, further comprising forming one or more additional fatty acids from the drilling additive formulation in situ within the drilling fluid.

28. The method of claim 25, wherein:the fatty acid composition includes one or more maleated fatty acids; and the drilling additive formulation includes at least one amidoamine and at least one glycol.

29. The method of claim 28, wherein:the one or more maleated fatty acids are about 10 weight percent (wt %) to about 40 wt % of the drilling additive formulation;the at least one amidoamine is about 25 wt% to about 55 wt % of the drilling additive formulation;the biodiesel is about 10 wt % to 40 wt % of the drilling additive formulation; and the at last one glycol includes butoxytriglycol and the butoxytriglycol is about 1 wt % to about 20 wt % of the drilling additive formulation.

30. The method of claim 25, further comprising mixing water with the drilling additive formulation, wherein the water is less than about 2 wt % of the drilling additive formulation.

31. The method of claim 25, wherein mixing a drilling additive formulation with a drilling fluid includes flowing the drilling additive formulation from a drum or a barrel into the drilling fluid.

32. The method of claim 25, wherein pumping the drilling fluid including the additive formulation into the earth formation includes forming a borehole in the earth formation while pumping the drilling fluid including the drilling additive formulation into the earth formation.

33. A drilling additive formulation of nonaqueous fluids, the drilling additive formulation comprising:Attorney Docket No. IS24.1206-WOa fatty acid composition including one or more maleated fatty acids, wherein the one or more maleated fatty acids are about 10 weight percent (wt %) to about 40 wt % of the drilling additive formulation;at least one amidoamine, wherein the at least one amidoamine is about 25 wt % to about 55 wt % of the drilling additive formulation;a biodiesel, wherein the biodiesel is about 10 wt % to 40 wt% of the drilling additive formulation; andbutoxytriglycol, wherein the butoxytriglycol is about 1 wt % to about 20 wt % of the drilling additive formulation.

34. The drilling additive formulation of claim 33, wherein:the one or more maleated fatty acids are about 20 wt % to about 30 wt % of the drilling additive formulation;the at least one amidoamine is about 35 wt% to about 45 wt% of the drilling additive formulation;the biodiesel is about 20 wt % to 30 wt % of the drilling additive formulation; and butoxytri glycol is about 5 wt % to about 15 wt % of the drilling additive formulation.

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