Clayless invert emulsion drilling fluid

Abstract

An invert emulsion fluid composition for drilling a borehole includes an oleaginous external phase, a non-oleaginous internal phase, an amidoamine-based emulsifier; a rheology agent, and an oil wetting agent, wherein the invert emulsion fluid is free of clay-base drilling fluid additives. Related methods of forming a borehole and related drilling fluids are also disclosed.

Description

PCT Patent Application Attorney Docket No. IS24.0675-WO-PCT CLAYLESS INVERT EMULSION DRILLING FLUID CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of United States Patent Application No.63 / 656,451, filed on June 5, 2024, which is entirely incorporated herein by reference. FIELD

[0002] The technology described herein relates to invert emulsion fluids. Specifically, stable invert emulsion fluids are described herein that can be used as drilling fluids, but that do not use added clay materials for density or rheology modification. BACKGROUND

[0003] During the drilling of a wellbore, various fluids are typically used in the well for a variety of functions. The fluids may be circulated through a drill pipe and drill bit into the wellbore, and then may subsequently flow upward through wellbore to the surface. During this circulation, the drilling fluid may act to remove drill cuttings from the bottom of the hole to the surface, to suspend cuttings and weighting material when circulation is interrupted, to control subsurface pressures, to maintain the integrity of the wellbore until the well section is cased and cemented, to isolate the fluids from the formation by providing sufficient hydrostatic pressure to prevent the ingress of formation fluids into the wellbore, to cool and lubricate the drill string and bit, and / or to maximize penetration rate.

[0004] In most rotary drilling procedures the drilling fluid takes the form of a “mud,” i.e., a liquid having solids suspended therein. The solids function to increase the density of the drilling fluid in order to provide a suitable hydrostatic pressure at the bottom of the well. The drilling mud may be either a water-based or an oil-based mud.

[0005] Many types of fluids have been used in well bores particularly in connection with the drilling of oil and gas wells. The selection of an oil-based well bore fluid involves a careful balance of the good characteristics of such fluids in a particular application. An oil-based drilling fluid provides superior hole stability, especially in shale formations, forms of a thinner filter cake than the filter cake achieved with a water based mud, provides excellentPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT lubrication of the drilling string and downhole tools, and provides penetration of salt beds without sloughing or enlargement of the hole, along with other benefits that should be known to one of skill in the art. An especially beneficial property of oil-based muds is their excellent lubrication qualities. These lubrication properties permit the drilling of wells having a significant vertical deviation, as is typical of off-shore or deep water drilling operations or when a horizontal well is desired. In such highly deviated holes, torque and drag on the drill string are a significant problem because the drill pipe lays against the low side of the hole, and the risk of pipe sticking is high when water-based muds are used. In contrast oil-based muds provide a thin, slick filter cake which helps to prevent pipe sticking.

[0006] Oil-based drilling fluids are generally used in the form of invert emulsion muds. The components of the invert emulsion fluids include an oleaginous liquid such as hydrocarbon oil which serves as a continuous phase, a non-oleaginous liquid such as water or brine solution which serves as a discontinuous phase, and an emulsifying agent, which may be a surfactant or other suitable type of emulsifier. The emulsifying agent helps to form a stable dispersion of fine aqueous droplets in the oleaginous liquid. A full description of such invert emulsions may be found in Composition and Properties of Drilling and Completion Fluids, 5th Edition, H. C. H. Darley, George R. Gray, Gulf Publishing Company, 1988, pp. 328-332, the contents of which are hereby incorporated by reference. Additionally, such invert emulsion muds generally contain one or more weighting agents, surfactants, viscosifiers, fluid loss control agents or bridging agents.

[0007] Typically, clay is included in drilling fluids as an additive to increase viscosity to improve their performance. However, the addition of clay may result in higher tendencies of mechanical washouts or erosions of oilfield tubulars and pumping equipment. Typical organophilic clay contents in invert emulsion fluids are usually 5 - 12 pounds per barrel (“ppb”) or above 1.5% by weight, depending on fluid formulation and desired rheology. Low organophilic clay levels are considered in the range of < 2 ppb or between 0.1 -1% by weight.

[0008] Hence, there is a need to provide a drilling fluid that is capable of improved hole cleaning without addition of clay-based products. SUMMARY

[0009] Embodiments described herein provide an invert emulsion fluid comprising an oleaginous external phase; a non-oleaginous internal phase; an amidoamine-basedPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT emulsifier; and a rheology modifier consisting of one or more aminated fatty acids, a fatty acid dimer, or both, wherein the invert emulsion fluid is free of clay-based drilling fluid additives.

[0010] Other embodiments described herein provide a method of performing wellbore operations comprising circulating an invert emulsion fluid in a wellbore; wherein the invert emulsion fluid comprises an oleaginous external phase; a non-oleaginous internal phase; an amidoamine-based emulsifier; and a rheology modifier consisting of one or more aminated fatty acids, a fatty acid dimer, or both, wherein the invert emulsion fluid is free of clay-based drilling fluid additives.

[0011] Other embodiments described herein provide an invert emulsion fluid comprising an oleaginous external phase; a non-oleaginous internal phase; an emulsifier containing a fatty acid amidoamine as a primary active ingredient; and a rheology agent comprising a solvent component and a rheology modifier consisting of one or more aminated fatty acids, a fatty acid dimer, or both, wherein the invert emulsion fluid is free of clay-based drilling fluid additives. DETAILED DESCRIPTION

[0012] Invert emulsion fluids are described herein that can be used as drilling fluids. The invert emulsion drilling fluid may be used in wellbore fluids, such as workover fluids, spacer fluids (e.g., a fluid introduced into the wellbore after a drilling fluid and prior to a cement composition to flush residual drilling fluid from the annulus), stimulation fluids, or other wellbore fluids. The invert emulsion drilling fluid may be used during drilling of a wellbore or borehole for producing hydrocarbons, for storing hydrocarbons, or for forming other types of wellbores. The invert emulsion drilling fluid is not limited to the particular type of borehole or wellbore being drilled.

[0013] The invert emulsion fluids described herein may include an oleaginous external phase, a non-oleaginous internal phase, an amidoamine-based emulsifier, an oil wetting agent, and a rheology agent, wherein the invert emulsion fluid is free of clay-base drilling fluid additives.

[0014] In some embodiments, a method of performing wellbore operations includes circulating an invert emulsion fluid in a wellbore, wherein the invert emulsion fluid includes, an oleaginous external phase, a non-oleaginous internal phase, an emulsifier; and optionallyPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT an oil wetting agent; wherein the invert emulsion fluid is without clay-base drilling fluid additives.

[0015] In some embodiments, the method of performing wellbore operations includes circulating the invert emulsion fluid in the wellbore occurs during any of drilling or completion of the wellbore.

[0016] The compositions and methods herein can provide a clayless invert emulsion drilling fluid. More specifically, compositions herein include invert emulsion drilling fluids that use diesel or a synthetic base oil as the external phase with brine water as the internal phase (calcium chloride or other) without the use of any clay-based drilling fluid additives, organophilic or otherwise. The fluid composition consists of no components made up of any clay base material outside of any naturally occurring clay components found in drilled solids while drilling. Those skilled in the art would understand ‘’clay’’ includes, but is not limited to, a mineral such as bentonite, smectite, sepiolite, kaolinite, either treated or un-treated).

[0017] Stable and functional rheology can be achieved for the suspension of weighting material as well as hole cleaning without the use of any clay-based products. Elimination of clay-based materials for viscosity results in a fluid with lower overall solids content providing reduced pressure downhole and reduced mechanical washout or erosion tendency of oilfield tubulars downhole or pumping equipment on surface.

[0018] Fluid properties are achieved by utilizing a stable invert emulsion created by an amidoamine-based emulsifier. Examples of such emulsifiers include, but are not limited to, the RheMul, Rhemax-P, and VERSACOAT HF emulsifier products available from SLB of Houston, Texas. Each of these products has an amidoamine compound as the primary active ingredient, and in some products the amidoamine compound is the primary ingredient, and these products can be used in combination. RheMul is more effective in lower temperature and / or lower density applications, while Rhemax-P and VERSACOAT HF will be more effective in higher temperature and / or higher density applications. A mixture of the above products can be specified based on temperature and density of the application.

[0019] The amidoamine compound may be an amidoamine derivative of a fatty acid compound, which may be saturated or unsaturated. For example, the amidoamine compound may be a reaction product of an amine, for example a diamine or triamine such as ethylenediamine or diethylenetriamine, and a fatty acid, which may be a C8 – C30 fattyPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT acid. In other cases, the emulsifier may contain a polymer comprising diethanolamine and diethylenetriamine. The emulsifier may consist of, or consist essentially of, the amidoamine compound, or the emulsifier may include other compounds. The commercial products above, for example, contain other compounds to broaden the potential uses of the product. For example, the emulsifier may include an amidoamine in a range of 45- 65% wt, a fatty acid in a range of 10-40% wt, a fatty acid dimer in a range of 2-10% wt, a glycol ether in a range of 5-15% wt, a Paraffin in a range of 20-30% wt, and an oil wetting agent, which may be a surfactant such as a fatty acid.

[0020] Oil wetting agents can also be separately added to the composition. Examples of oil wetting agents that can be used include, but are not limited to, the SUREWET™ and VERSAWET oil wetting agents available from SLB of Houston, Texas, each of which is a surfactant designed for use with oil-based fluids. These wetting agents can be used in combination. VERSAWET has a concentration of active ingredients that is about 50% that of SUREWET, so more VERSAWET would be used to obtain similar results to SUREWET. In some cases, the composition can achieve the characteristics described herein without using an oil wetting agent, so the oil wetting agent is optional.

[0021] A stable invert emulsion provides the basis for the rheology that can suspend weighting agents, including ground barite, and properly clean the hole while drilling. Additional modification of rheology is available with the adjustment of the oil / water ratio. Increasing the oil / water ratio results in a lower rheology while lowering the oil / water ratio results in a higher rheology. A useful oil / water ratio is between 85:15 - 60:40 depending on the desired fluid density and rheology profile.

[0022] Rheology can further be modified with the use of a non-clay based rheology agent which may include, as a rheology modifier, a fatty acid, fatty acid dimers, a polymer with diethanolamine and diethylenetriamine, dimerized fatty acid, or combinations thereof. In some cases, the rheology modifier consists of one or more aminated fatty acids, a fatty acid dimer, or both. In some cases, a rheology agent comprises a solvent component, such as water or alcohol, along with a rheology modifier described above. Thus, for example, a rheology agent may comprise a solvent component and a rheology modifier that consists of one or more aminated fatty acids, a fatty acid dimer, or both. Rheology agents that can be used include, but are not limited to, HRP and VERSAMOD, both available from SLB ofPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT Houston, Texas. These agents can be used in combination, and are used in similar quantities in an invert emulsion composition.

[0023] A typical composition using the various products mentioned above is shown in Table 1: Table 1 – Formulation Ranges Oil / Water: 85:15 – 60:40 CaCl2: 22-26 wt% T

[0024] Desired property ranges for an invert emulsion that could be used as a drilling fluid in certain cases are shown below. The fluid properties were measured as per API 13B-2 standards (herein incorporated by reference): Plastic Viscosity (600RPM – 300 RPM) = ≤3x Fluid Density After hot roll or while drilling Yield Point (300 RPM – Plastic Viscosity) = 0.8 – 1.5x Fluid Density After hot roll or while drilling LSYP (2xR3 – R6) = ≥3 After hot roll or while drilling HTHP Fluid loss at 250F and 500 ∆psi = <10 ml / 30 mins Water in HTHP Filtrate at 250F = 0

[0025] An example formulation of an invert emulsion is shown below in Table 2. Properties of the formulation of Table 2 are shown below in Table 3. Table 2 – Example Fluid Formulation Density: 12.50 ppg OWR: 70.00 / 30 CaCl2 : 24.62%weightPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT Products / Unit Concentration –Reference BHR 200F API AHR 200F API FPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT lb / 100ft2ES T F12000 12000ffPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT

[0026] The embodiments of wellbore (e.g., drilling) fluids including the invert emulsion drilling fluid composition have been primarily described with reference to wellbore drilling operations; the drilling fluids described herein may be used in applications other than the drilling of a wellbore or borehole. In other embodiments, wellbore fluids including the invert emulsion drilling fluid 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.

[0027] 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 be used to form boreholes and / or wellbores without introducing materials to the earth formation that may impede subsequent storage of carbon in the earth formation.

[0028] 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.

[0029] 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 hydrocarbonPCT Patent Application Attorney Docket No. IS24.0675-WO-PCT 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.

[0030] 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 and business-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.

[0031] 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.PCT Patent Application Attorney Docket No. IS24.0675-WO-PCT

[0032] 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, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims.

[0033] The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements.

[0034] The present disclosure may be embodied in other specific forms without departing from its spirit or characteristics. The described embodiments are to be considered as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. Changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

PCT Patent Application Attorney Docket No. IS24.0675-WO-PCT CLAIMS What is claimed is:

1. An invert emulsion fluid comprising: an oleaginous external phase; a non-oleaginous internal phase; an amidoamine-based emulsifier; and a rheology modifier consisting of one or more aminated fatty acids, a fatty acid dimer, or both, wherein the invert emulsion fluid is free of clay-based drilling fluid additives.

2. A method of performing wellbore operations comprising: circulating an invert emulsion fluid in a wellbore; wherein the invert emulsion fluid comprises: an oleaginous external phase; a non-oleaginous internal phase; an amidoamine-based emulsifier; and a rheology modifier consisting of one or more aminated fatty acids, a fatty acid dimer, or both, wherein the invert emulsion fluid is free of clay-based drilling fluid additives.

3. An invert emulsion fluid comprising: an oleaginous external phase; a non-oleaginous internal phase; an emulsifier containing a fatty acid amidoamine as a primary active ingredient; and a rheology agent comprising a solvent component and a rheology modifier consisting of one or more aminated fatty acids, a fatty acid dimer, or both, wherein the invert emulsion fluid is free of clay-based drilling fluid additives.

4. The invert emulsion fluid or method of any of claims 1-3, further comprising an oil wetting agent.PCT Patent Application Attorney Docket No. IS24.0675-WO-PCT 5. The invert emulsion fluid or method of any of claims 1-4, wherein the ratio of the oleaginous external phase to non-oleaginous internal phase is between 85:15 and 60:

40.

6. The invert emulsion fluid or method of any of claims 1-5, wherein the oleaginous external phase comprises a diesel or a synthetic base oil.

7. The invert emulsion fluid or method of any of claims 1-6, wherein the non-oleaginous internal phase comprises at least one divalent brine.

8. The invert emulsion fluid or method of any of claims 1-7, wherein the non-oleaginous internal phase comprises calcium chloride.

9. The invert emulsion fluid or method of any of claims 1-8, wherein the non-oleaginous internal phase comprise water.

10. The invert emulsion fluid or method of any of claims 1-9, wherein the emulsifier comprises an amidoamine in a range of 45-65% wt, a fatty acid in a range of 10-40% wt, a fatty acid dimer in a range of 2-10% wt, a glycol ether in a range of 5-15% wt, a Paraffin in a range of 20-30% wt, and combinations thereof.

11. The invert emulsion fluid or method of any of claim 4, wherein the oil wetting agent comprises a fatty acid.

12. The invert emulsion fluid or method of any of claims 1-11, wherein the rheology modifier comprises an aminated fatty acid that is a reaction product of a fatty acid and ethylenediamine, diethylenetriamine, or both.

13. The invert emulsion fluid or method of any of claims 1-12, further comprising ground barite, gilsonite, or both.

14. The invert emulsion fluid or method of any of claims 1-13, further comprising lime.PCT Patent Application Attorney Docket No. IS24.0675-WO-PCT 15. The method of performing wellbore operations of claim 2, wherein the circulating the invert emulsion fluid in the wellbore occurs during any of drilling or completion of a wellbore.

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