Nanobubble enhanced stimulation fluids

Abstract

A stimulation fluid to prevent coacervate formation in a subterranean formation. The stimulation fluid generally comprises nanobubbles, a cationic component, and an anionic component. The cationic component may be a biocide, scale control additive, clay control additive, water control or friction reducing polymer, surfactant, or a combination of cationic components. The anionic component may be a surfactant, scale inhibitor, chelant, water control or friction reducing polymer, or a combination of anionic components.

Description

[0001] NANOBUBBLE ENHANCED STIMULATION FLUIDS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to wellbore operations, and more particularly, to the use of nanobubbles to prevent coacervate formation within stimulation fluids to be introduced into a subterranean formation.

[0004] BACKGROUND

[0005] Hydrocarbon resources are generally located in subterranean porous rock formations. Wells must be drilled in order to access these resources. Drilling and fracturing of the rock formation may damage the formation physically or chemically due to the interaction between the drill bit, a reamer, or the drilling fluid and the rocks and minerals in the formation. For example, clay particulates may deposit on the face of the wellbore, forming a layer adhered to the wellbore wall. Additionally, friction increases as wellbores become agglomerated with various different particulates such as drilling mud, clay, and other debris in the wellbore.

[0006] Typically, enhanced oil recovery techniques are employed to extract additional oil from the subterranean formation after primary recovery by injecting water into the formation to mobilize oil for production from the formation. The injected water may drive a portion of the oil in the formation to a well for production from the formation. Oil not produced from the formation may be trapped within pores in the formation by capillary action of water extending across the pore throats of the pores. As a result, a significant quantity of oil located in the portions of the formation may be left in the formation and not recovered by the waterflood.

[0007] Additional additives may be added to the water to create a stimulation fluid to improve oil recovery such as clay control additives and friction reducing polymers. Clay control additives may have a cationic charge and friction reducing polymers may have an anionic charge. These oppositely charged molecules may attract and cause the formation of coacervates, or dense agglomerations of electrostatically attracted chemical complexes in equilibrium with the surrounding fluid. The coacervates form within the stimulation fluid and may impact wellbore operations. As such, improvements to these stimulation fluids are desirable. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Illustrative examples of the present disclosure are described in detail below with reference to the attached drawing figures, which are incorporated by reference herein, and wherein:

[0009] FIG. 1 is a schematic illustrating a system of surface equipment for the preparation and delivery of a stimulation fluid to a wellbore in accordance with one or more examples described herein;

[0010] FIG. 2 is a schematic illustrating the placement of a stimulation fluid into a fracture in a subterranean formation in accordance with one or more examples described herein; and

[0011] FIG. 3 is a schematic illustrating the treatment of an injection well in accordance with one or more examples described herein.

[0012] FIG. 4 is a diagrammatic example of nanobubble-assisted charge-shielding of fluid additives.

[0013] The illustrated figures are only exemplary and are not intended to assert or imply any limitation with regard to the environment, architecture, design, or process in which different examples may be implemented.

[0014] DETAILED DESCRIPTION

[0015] The present disclosure relates generally to wellbore operations, and more particularly, to the use of nanobubbles to prevent the formation of coacervates or complex coagulates within stimulation fluids.

[0016] In the following detailed description of several illustrative examples, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific examples that may be practiced. These examples are described in sufficient detail to enable those skilled in the art to practice them, and it is to be understood that other examples may be utilized, and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the disclosed examples. To avoid detail not necessary to enable those skilled in the art to practice the examples described herein, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the illustrative examples are defined only by the appended claims.

[0017] Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the examples of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. It should be noted that when “about” is at the beginning of a numerical list, “about” modifies each number of the numerical list. Further, in some numerical listings of ranges some lower limits listed may be greater than some upper limits listed. One skilled in the art will recognize that the selected subset will require the selection of an upper limit in excess of the selected lower limit.

[0018] In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” Unless otherwise indicated, as used throughout this document, “or” does not require mutual exclusivity.

[0019] The terms uphole and downhole may be used to refer to the location of various components relative to the bottom or end of a well. For example, a first component described as uphole from a second component may be further away from the end of the well than the second component. Similarly, a first component described as being downhole from a second component may be located closer to the end of the well than the second component.

[0020] The terms upstream and downstream may be used to refer to the location of various components relative to one another in regards to the flow of a sample through said components. For example, a first component described as upstream from a second component will encounter a sample before the downstream second component encounters the sample. Similarly, a first component described as being downstream from a second component will encounter the sample after the upstream second component encounters the sample. As used herein the weight / volume percentage (“w / v”) is to be understood to mean grams / 100 milliliters.

[0021] The present disclosure relates generally to wellbore operations, and more particularly, to the use of a stimulation fluid comprising nanobubbles to prevent coacervate formation. Coacervates or complex coagulates are dense agglomerations in equilibrium with the surrounding fluid and may form due to incompatibility between cationic and anionic stimulation fluid additives during the production phase and enhanced oil recovery phase of a well. The mixed cationic and anionic charges in a liquid phase attract, forming the dense agglomerations known as coacervates. Coacervates may cause issues with wellbore machinery as well as induce pore plugging within the formation. Advantageously, the stimulation fluid may comprise nanobubble formulations that are compatible with both cationic clay control additives and anionic friction reducing polymers. The combination of the cationic clay control additives and anionic friction reducing polymers with the mixed charges of the nanobubbles creates a stimulation fluid exhibiting charge- shielding effects. Positively charged nanobubbles shield anionically charged additives and negatively charged nanobubbles shield cationically charged additives. This shielding reduces coacervate or complex coagulate formation and may improve longevity of the stimulation fluid in a hydrocarbon producing zone. The stimulation fluid generally comprises nanobubbles, a cationic component, and an anionic component. The cationic component may be a biocide, scale control additive, clay control additive, water control or friction reducing polymer, surfactant, or a combination of cationic components. The anionic component may be a surfactant, scale inhibitor, chelant, water control or friction reducing polymer, or a combination of anionic components.

[0022] The stimulation fluid may comprise a nanobubble dispersion in a liquid carrier. The nanobubble dispersion comprises a plurality of nanobubbles. Nanobubbles are bubbles having a mean diameter between about 50 nm to about 1000 nm. The nanobubbles are formed on the surface either at the wellsite or at an offsite location and then transported to the wellsite. After their formation, the nanobubbles may then be combined with the other components of the stimulation fluid. When the stimulation fluid is not needed, the stimulation fluid containing the nanobubbles may be stored or transported to another location for later use due to their intrinsic stability and longevity.

[0023] The nanobubbles may be formed by any suitable manner. One mechanical method for forming the nanobubbles generally includes using a tube, in particular, a ceramic tube coated with a metallic oxide to inject nanobubbles into a liquid carrier. Through the wall of the tube, pores are machined or otherwise disposed in the tube wall and used to provide a channel from the interior of the tube to the exterior of the tube. It is preferable, but not required to use a tube having a constant pore size. The tube is placed within a container or vessel in which a liquid carrier (e.g., water) is flowed. The liquid carrier is flowed around the tube in a way to generate a turbulent flow of the liquid carrier, for example, the liquid carrier may be introduced into the vessel at an oblique or right angle relative to the tube. A gas is introduced into the lumen of the tube at a pressure greater than the fluid pressure in the vessel, thereby forcing the gas through the pores in the tube and into the liquid carrier flowing in the vessel. The pore size in the tube wall produces nanobubbles of the desired size as the gas is flowed through the pores into the liquid carrier. Ceramic may be used as the tube material, but generally the tube can be produced from any rigid material adapted for maintaining a desired pore size when its lumen is filled with a pressurized gas. Maintaining a constant pore size can be beneficial for controlling the diameter range and mean diameter of the nanobubbles formed in the liquid carrier. As such, preferred materials for the tube are those having sufficient strength or wall thickness for maintaining a constant pore size when a pressurized gas is introduced into the lumen of the tube.

[0024] In a specific example, the tube is a single channel ceramic membrane coated with metallic oxides (such as alumina, titania, zirconia, manganese, or combinations thereof). However, it is to be understood that the tube is not limited to any form or size of structure and can be in the form of monolith, multichannel tubes, etc. A singular mean pore size between about 50 nm to about 500 nm is used depending on the size of the bubble desired. Specific examples of metallic oxide coatings are AI2O3 or TiO crystalline coatings with a known mean pore size. The tube length, diameter, and size of the lumen can be any value sufficient for introduction of the gas into the liquid carrier.

[0025] In some examples, the liquid carrier may be an aqueous fluid. In other examples, an organic liquid may be used. The choice of the liquid carrier may be selected based on the other components of the stimulation fluid and the chosen wellbore operation. In some examples, the liquid carrier is free or substantially free of surfactants. The liquid carrier should be flowed around the tube in a turbulent manner to prevent the nanobubbles from coalescing into larger bubbles. The liquid carrier may be introduced into the vessel at an oblique or right angle relative to the tube in order to enhance the turbulence of the liquid carrier.

[0026] A selected gas is introduced into the tube under pressure from a gas source. The gas may be air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas, or combinations thereof. In some examples, the oxidizing gas is held in the stable nanobubble which protects any fluid additives from oxidation during pumping. Once the nanobubbles eventually become unstable, the released gas acts as an oxidative breaker for the fluid additives. As the tube is closed (apart from its inlet), the gas can only exit through the pores of the tube. A pressure differential is maintained between the gas pressure inside the lumen of the tube and the liquid pressure outside the tube so that gas is forced through the pores of the tube. The gas emerges from the tube lumen as nanobubbles pulled into the turbulently flowing stream of the liquid carrier on the outside of the tube. The turbulent flow of the liquid carrier performs two functions. The liquid carrier removes the nanobubbles from the surface of the tube and carries away the nanobubbles as they form to prevent the nanobubbles from coalescing into large bubbles. The velocity of the liquid carrier may be any velocity sufficient for pulling the nanobubbles into the liquid carrier as the liquid carrier flows over the pores of the tube.

[0027] The gas used to prepare the nanobubbles may be air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas (likely oxygen, carbon monoxide (CO), chlorine dioxide (CIO2), bromine gas (B ), fluorine gas (F2), chlorine monofluoride (C1F), ozone (O3), nitrous oxide (N2O), nitric oxide (NO), dinitrogen tetroxide (N2O4), nitrogen dioxide (NO2)), or combinations thereof. In some examples, the oxidizing gas is held in the stable nanobubble which protects any fluid additives from oxidation during pumping. The oxidation process is an electrochemical process whereby a chemical species gains or receives an electron(s), to another chemical agent or material, thereby becoming oxidized; the electrochemical series defines or establishes the position of oxidizing agents with respect to the standard potential of hydrogen. Once the nanobubbles eventually become unstable, the released gas acts as an oxidative breaker for the fluid additives and / or carbonaceous components naturally present in the hydrocarbon fluid. In preferred examples, the gas in the nanobubbles remains in a gaseous state at downhole conditions, such as a pressure in a range of from about 1000 to 3000 pounds per square inch (psi) and at a temperature of at least about 100° C. It some examples, it is preferable that the gas does not transition to a critical or supercritical state while downhole. This transition may negatively impact the stability of the nanobubble.

[0028] In some optional examples, the nanobubbles may be further configured to improve stability or add functionalization to chemical additives used in the preparation of the nanobubbles themselves or other additives. For example, the nanobubble surface ionization (exterior surface charge) may be selected based upon the properties of the stimulation fluid and / or the hydrocarbon fluid within the subterranean formation. Surfactants or other types of surface modifiers may be added to the nanobubble dispersion (i.e., the dispersed nanobubbles within the liquid carrier) and / or the stimulation fluid. Ionic surfactants, such as SDS (sodium dodecyl sulphate), CTAB (cetyltrimethylammonium bromide), and DTAB (dodecyl trimethylammonium bromide); non-ionic surfactants, such as the TWEEN™ series of detergents, e.g., TWEEN-20™ polyoxyethylene (20) sorbitan monolaurate, and TRITON X- 100™ (octylphenol ethoxylate); and / or zwitterionic surfactants, such as CBS (cocamidopropyl hydroxysultaine), may be introduced to the nanobubble dispersion and / or the stimulation fluid. Surface functionalization of the nanobubbles may be selected based upon the target subterranean formation of the wellbore and / or the properties of the hydrocarbon fluid within the subterranean formation. Surface functionalization may be performed through the use of surface modifiers configured to add functional groups such as -COOH, -OH, and -C=O, -NHR2, -NH2R, -NR3, -[NR4]+, OS(=O)2O-R, R-0P(=0)(0H)2, and salts thereof. Functionalization either through the addition of surfactants and / or other types of surface modifiers may be used to modify the exterior surface charge of the nanobubble to impart attraction or repulsion to other charged surfaces, such as water molecules, stimulation fluid additives, and / or other nanobubbles. In some examples, surface polarization may include common surface modifiers that either add dipoles or induce ionic polarization such as zwitterionic surfactants. In some examples, the nanobubble surfaces may be modified to repel other nanobubbles to prevent coalescence and increase the residence time and overall stability of the nanobubbles in the stimulation fluid. The use of surface modifiers is optional, and these materials may not be present in all examples.

[0029] In some examples, the nanobubbles are produced and dispersed within the carrier liquid without the inclusion of surfactants or any functionalizing additives. In some examples, the nanobubble dispersion may consist entirely of the nanobubbles and the carrier liquid. In some examples, the nanobubbles may be natively charged in a sufficient manner to repel each other and maintain stability in an aqueous fluid. In particular, some examples of the nanobubbles, such as those comprising air, may be negatively charged without the use of surfactants or functionalizing agents. As such, surfactants may not be necessary to provide nanobubbles having a mechanically induced repulsive character in the liquid carrier or the stimulation fluid. In some examples, the nanobubble dispersion may be negatively charged, positively charged, or contain a mixture of negatively and positively nanobubbles. In some examples, the nanobubble dispersion may consist of 0.1 % (v / v) negatively charged nanobubbles and 99.9% (v / v) positively charged nanobubbles. In some examples, the nanobubble dispersion may consist of 99.9 % (v / v) negatively charged nanobubbles and 0.1% (v / v) positively charged nanobubbles. The distribution of nanobubbles in the nanobubble dispersion may be affected by the pH of the stimulation fluid. The pH of the stimulation fluid may be adjusted by various additives present in the stimulation fluid.

[0030] In some examples, positively charged nanobubbles are predominantly generated in an aqueous base fluid when the aqueous base fluid is maintained at a pH of 3 or less. In other examples, wherein the pH is nominally equal to or greater than 3, the surface of a nanobubble is negatively charged. Additionally, the point of zero charge (“PZC”) is equal to < 0 mV nominally at pH of 3. When the pH is at or near 3, the PZC is determined by the physicochemical properties of the nanobubble dispersion. The pH values of the nanobubble dispersion are greatly influenced by the ionic strength of the aqueous base fluid. The ionic strength of the aqueous base fluid is influenced by a number of different factors, including: the salinity and total dissolved solids, the type of gas, and the inclusion of any additive such as surfactants, organic molecules, or solvents. Additionally, the pH value of the aqueous base fluid can shift dynamically during preparation of the stimulation fluid by as much as + / -1 pH unit to as much as + / -2 pH units. In some examples, the pH value of the aqueous base fluid can shift by as much as + / -3 pH unit to as much as + / -4 pH units.

[0031] Another factor which influences the ionic strength of the aqueous base fluid is the zeta potential. The zeta potential can range from -10 to -50 mV when ultrapure water and certain gases (e.g., O2, N2, air, CO2, Xe, or combinations thereof) are used to prepare the nanobubble dispersion. In some examples, the zeta potential may range from -25 to -45 mV at a neutral pH as a function of ionic strength. In some examples, when surfactants are included within the stimulation fluid, the zeta potential can range from +45 to +60 mV.

[0032] The nanobubbles have a mean diameter in a range of between about 50 nm to about 1000 nm. For example, the nanobubbles may have a mean diameter ranging from about 50 nm to about 1000 nm, about 50 nm to about 750 nm, about 50 nm to about 500 nm, about 75 nm to about 200 nm, or about 50 nm to about 150 nm. In some examples, the nanobubbles have a unimodal distribution of diameters. In some examples, the nanobubbles have a multimodal distribution of diameters.

[0033] The nanobubble dispersion described herein comprises a sufficiently concentrated volume of nanobubbles dispersed in the liquid carrier. In some examples, the nanobubbles have a population in the liquid carrier of between about 1 million to about 100 million nanobubbles per mL of liquid carrier. When the nanobubble dispersion is added to the stimulation, the population of the nanobubbles in the stimulation fluid will vary based on the population of the nanobubbles in the dispersion and the volume of the nanobubble dispersion added to the stimulation fluid as a portion of the total volume of the stimulation.

[0034] In some examples, the nanobubbles have a droplet resonance time of at least 24 days under ambient conditions at the surface. Conditions at wellsites may range from about 35° F to about 115° F. In some embodiments, ambient conditions at wellsites may range from about 35° F to about 130° F. For example, the nanobubbles may have a droplet resonance time of at least 3 days, at least 5 days, at least 10 days, at least 15 days, at least 20 days, or at least 24 days.

[0035] To prepare the stimulation fluid, a volume of the nanobubble dispersion is combined with one or more of the other components of the stimulation fluid. The combining of the stimulation fluid components may occur in any order. The nanobubble dispersion is combined with one or more of the other components of the stimulation fluid at the surface, either at the wellsite or another location to then be transported to the wellsite. As the nanobubble dispersion is combined with the other components of the stimulation fluid, the nanobubbles within the dispersion will then disperse within the stimulation fluid.

[0036] The concentration of the nanobubble dispersion in a stimulation fluid may range from about 0.1% w / v to about 50% w / v. The concentration may range from any lower limit to any upper limit and encompass any subset between the upper and lower limits. Some of the lower limits listed may be greater than some of the listed upper limits. One skilled in the art will recognize that the selected subset may require the selection of an upper limit in excess of the selected lower limit. Therefore, it is to be understood that every range of values is encompassed within the broader range of values. For example, the concentration of the nanobubble dispersion in the stimulation fluid may range from about 0.1% (w / v) to about 50% (w / v), from about 0.5% (w / v) to about 50% (w / v), from about 1% (w / v) to about 50% (w / v), from about 2% (w / v) to about 50% (w / v), from about 3% (w / v) to about 50% (w / v), from about 4% (w / v) to about 50% (w / v), from about 5% (w / v) to about 50% (w / v), from about 6% (w / v) to about 50% (w / v), from about 7% (w / v) to about 50% (w / v), from about 8% (w / v) to about 50% (w / v), from about 9% (w / v) to about 50% (w / v), from about 10% (w / v) to about 50% (w / v), from about 11% (w / v) to about 50% (w / v), from about 12% (w / v) to about 50% (w / v), from about 13% (w / v) to about 50% (w / v), from about 14% (w / v) to about 50% (w / v), from about 15% (w / v) to about 50% (w / v), from about 16% (w / v) to about 50% (w / v), from about 17% (w / v) to about 50% (w / v), from about 18% (w / v) to about 50% (w / v), from about 19% (w / v) to about 50% (w / v), from about 20% (w / v) to about 50% (w / v), from about 25% (w / v) to about 50% (w / v), from about 30% (w / v) to about 50% (w / v), from about 35% (w / v) to about 50% (w / v), from about 40% (w / v) to about 50% (w / v), or from about 45% (w / v) to about 50% (w / v). As another example, the concentration of the nanobubble dispersion in the stimulation fluid may range from about 0.1% (w / v) to about 50% (w / v), from about 0.1% (w / v) to about 45% (w / v), from about 0.1% (w / v) to about 40% (w / v), from about 0.1% (w / v) to about 35% (w / v), from about 0.1% (w / v) to about 30% (w / v), from about 0.1% (w / v) to about 25% (w / v), from about 0.1% (w / v) to about 20% (w / v), from about 0.1% (w / v) to about 19% (w / v), from about 0.1% (w / v) to about 18% (w / v), from about 0.1% (w / v) to about 17% (w / v), from about 0.1% (w / v) to about 16% (w / v), from about 0.1% (w / v) to about 15% (w / v), from about 0.1% (w / v) to about 14% (w / v), from about 0.1% (w / v) to about 13% (w / v), from about 0.1% (w / v) to about 12% (w / v), from about 0.1% (w / v) to about 11% (w / v), from about 0.1% (w / v) to about 10% (w / v), from about 0.1% (w / v) to about 9% (w / v), from about 0.1% (w / v) to about 8% (w / v), from about 0.1% (w / v) to about 7% (w / v), from about 0.1% (w / v) to about 6% (w / v), from about 0.1% (w / v) to about 5% (w / v), from about 0.1% (w / v) to about 4% (w / v), from about 0.1% (w / v) to about 3% (w / v), from about 0.1% (w / v) to about 2% (w / v), from about 0.1% (w / v) to about 1% (w / v), or from about 0.1% (w / v) to about 0.5% (w / v). With the benefit of this disclosure, one of ordinary skill in the art will be readily able to prepare a stimulation fluid having a desirable concentration of dispersed nanobubbles for use in a given wellbore operation.

[0037] The stimulation fluid additionally comprises a cationic component. The cationic component may be combined with the other stimulation fluid components in any order. Suitable cationic components are, but not limited to, arginine, lysine, polylysine, guanidine, ethoxylated amines, polyoxyalkylene amines, polyoxyethylene amines, polyoxypropylene amines, polyoxyalkylene cocamines, polyoxyethylene cocamines, polyoxypropylene cocamines, polyoxyalkylene tallow amines, polyoxyethylene tallow amines, polyoxypropylene tallow amines, polyoxyalkylene lauryl amines, polyoxyethylene lauryl amines, polyoxypropylene lauryl amines polyoxy alkylene amidoamines, polyoxypropylene amidoamine, polyether amines, polyether diamine, polyamino polyether, and the like, or combinations thereof. In some embodiments, an oligomer can comprise two or more repeating groups derived from one or more of the foregoing compounds.

[0038] Optionally, the cationic component may be a cationic clay control oligomer. The cationic clay control oligomer can comprise one or more functional groups selected from the group consisting of (a) I0-, 2°-, 3°-, or quaternary alkyl, vinyl, aryl amines; (b) 1°-, 2°-, 3°-, or quaternary alkyl, vinyl, aryl, cyclic amines; (c) I0-, 2°-, 3°-, or quaternary cyclic alkyl, vinyl, aryl, diamines; (d) I0-, 2°-, 3°-, or quaternary cyclic alkyl, vinyl, aryl, triamines; (e) I0-, 2°-, 3°-, or quaternary alkyl, vinyl, aryl, aminoalcohol moieties; (f) diol or glycerol alcohol moiety; (g) l,2-propanediol-3-trialkyl ammonium salts; (h) aminoacid moiety; (i) 1°-, 2°-, 3°-, or quaternary alkyl, vinyl, aryl, aminoformamidine; (j) I0-, 2°-, 3°-, or quaternary alkyl, vinyl, aryl, cyclic aminoformamidine; (k) I0-, 2°-, 3°-, or quaternary pyridinylmethly- aminoformamidine; (1) I0-, 2°-, 3°-, or quaternary aceto-aminoformamidine; (m) bisquaternary amine; (n) betaine monohydrate; and (o) combinations thereof.

[0039] The concentration of the cationic clay control oligomer in a stimulation fluid may range from about 0.001% w / w to about 5% w / w. The concentration may range from any lower limit to any upper limit and encompass any subset between the upper and lower limits. Some of the lower limits listed may be greater than some of the listed upper limits. One skilled in the art will recognize that the selected subset may require the selection of an upper limit in excess of the selected lower limit. Therefore, it is to be understood that every range of values is encompassed within the broader range of values. For example, the concentration of the cationic clay control oligomer in the stimulation fluid may range from about 0.001% (w / v) to about 5% (w / v), from about 0.005 (w / v) to about 5% (w / v), from about 0.01 (w / v) to about 5% (w / v), from about 0.05 (w / v) to about 5% (w / v), from about 0.1% (w / v) to about 5% (w / v), from about 0.5% (w / v) to about 5% (w / v), from about 1% (w / v) to about 5% (w / v), from about 2% (w / v) to about 5% (w / v), from about 3% (w / v) to about 5% (w / v), or from about 4% (w / v) to about 5% (w / v). As another example, the concentration of the cationic clay control oligomer in a stimulation fluid may range from about 0.001 % (w / v) to about 5% (w / v), from about 0.001 % (w / v) to about 4% (w / v), from about 0.001% (w / v) to about 3% (w / v), from about 0.001% (w / v) to about 2% (w / v), from about 0.001% (w / v) to about 1% (w / v), from about 0.001% (w / v) to about 0.5% (w / v), from about 0.001% (w / v) to about 0.1% (w / v), from about 0.001% (w / v) to about 0.05% (w / v), from about 0.001% (w / v) to about 0.01% (w / v), or from about 0.001% (w / v) to about 0.005% (w / v). With the benefit of this disclosure, one of ordinary skill in the art will be readily able to prepare and select a cationic clay control oligomer having a desirable concentration for a given application.

[0040] The stimulation fluid additionally comprises an anionic component. Optionally, the anionic component may be a friction reducing polymer. Suitable water-soluble friction reducing polymers may be synthesized from a variety of monomeric units. Typically, the composition of the water-soluble friction reducing polymer will be generally the same or about the same as the composition of the monomer mixture. The friction reducing polymer may be combined with the other stimulation fluid components in any order. Suitable friction reducing polymers are, but not limited to, acrylamide, acrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, acrylamido tertiary butyl sulfonic acid, N,N-dimethylacrylamide, vinyl sulfonic acid, N-vinyl acetamide, N-vinyl formamide, itaconic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters and combinations thereof. Examples of suitable water-soluble polymers may include, but not limited to, a polyacrylamide, a polyacrylamide derivative, a synthetic polymer, an acrylamide copolymer, an anionic acrylamide copolymer, a cationic acrylamide copolymer, a nonionic acrylamide copolymer, an amphoteric acrylamide copolymer, a polyacrylate, a polyacrylate derivative, a polymethacrylate, a polymethacrylate derivative, and combinations thereof. Examples of suitable water-soluble polymers may be in an acid form or in a salt form. As will be appreciated, a variety of salts may be prepared, for example, by neutralizing the acid form of the acrylic acid monomer or the 2-acrylamido-2- methylpropane sulfonic acid monomer. In addition, the acid form of the water-soluble polymer may be neutralized by ions present in the fracturing fluid. The concentration of the friction reducing polymer in a stimulation fluid may range from about 0.001% w / w to about 2% w / w. The concentration may range from any lower limit to any upper limit and encompass any subset between the upper and lower limits. Some of the lower limits listed may be greater than some of the listed upper limits. One skilled in the art will recognize that the selected subset may require the selection of an upper limit in excess of the selected lower limit. Therefore, it is to be understood that every range of values is encompassed within the broader range of values. For example, the concentration of the friction reducing polymer in the stimulation fluid may range from about 0.001 % (w / w) to about 2% (w / w), from about 0.01% (w / w) to about 2% (w / w), 0.1% (w / w) to about 2% (w / w), from about 0.5% (w / w) to about 2% (w / w), or from about 1% (w / w) to about 2% (w / w). As another example, the concentration of the sodium silicate in the stimulation fluid may range from about 0.0001% (w / w) to about 2% (w / w), 0.0001% (w / w) to about 1% (w / w), from about 0.0001% (w / w) to about 0.5% (w / w), from about 0.0001% (w / w) to about 0.1% (w / w), from about 0.0001% (w / w) to about 0.01% (w / w), or from about 0.0001% (w / w) to about 0.001% (w / w).

[0041] The stimulation fluid described herein comprises an aqueous base fluid, for example, freshwater, saltwater (e.g., water containing one or more salts dissolved therein), brine (e.g., saturated saltwater, including saturated saltwater produced from subterranean formations), seawater, produced water, recycled water, reclaimed water, municipal wastewater or any combination thereof. Generally, the aqueous base fluid may be from any source provided that the aqueous base fluid does not contain an excess of compounds that may undesirably affect other components in the stimulation fluid. In the case of brines, the aqueous base fluid may comprise a monovalent brine or a divalent brine. Suitable monovalent brines may include, for example, sodium chloride brines, sodium bromide brines, potassium chloride brines, potassium bromide brines, and the like. Suitable divalent brines can include, for example, magnesium chloride brines, calcium chloride brines, calcium bromide brines, zinc bromide brines, and the like. One of ordinary skill in the art, with the benefit of this disclosure, should be readily able to select an aqueous base fluid for a chosen application.

[0042] The concentration of the aqueous base fluid in the stimulation fluid may range from about 1% (w / v) to about 99% (w / v). The concentration of the aqueous base fluid in the stimulation fluid may range from any lower limit to any upper limit and encompass any subset between the upper and lower limits. Some of the lower limits listed may be greater than some of the listed upper limits. One skilled in the art will recognize that the selected subset may require the selection of an upper limit in excess of the selected lower limit. Therefore, it is to be understood that every range of values is encompassed within the broader range of values. For example, the concentration of the aqueous base fluid in the stimulation fluid may range from about 1% (w / v) to about 99% (w / v), from about 5% (w / v) to about 99% (w / v), from about 10% (w / v) to about 99% (w / v), from about 15% (w / v) to about 99% (w / v), from about 20% (w / v) to about 99% (w / v), from about 25% (w / v) to about 99% (w / v), from about 30% (w / v) to about 99% (w / v), from about 35% (w / v) to about 99% (w / v), from about 40% (w / v) to about 99% (w / v), from about 45% (w / v) to about 99% (w / v), from about 55% (w / v) to about 99% (w / v), from about 60% (w / v) to about 99% (w / v), from about 65% (w / v) to about 99% (w / v), from about 70% (w / v) to about 99% (w / v), from about 75% (w / v) to about 99% (w / v), from about 80% (w / v) to about 99% (w / v), from about 85% (w / v) to about 99% (w / v), from about 90% (w / v) to about 99% (w / v), or from about 95% (w / v) to about 99% (w / v). As another example, the concentration of the aqueous base fluid in the stimulation fluid may range from about 1% (w / v) to about 99% (w / v), from about 1% (w / v) to about 95% (w / v), from about 1% (w / v) to about 90% (w / v), from about 1% (w / v) to about 85% (w / v), from about 1% (w / v) to about 80% (w / v), from about 1% (w / v) to about 75% (w / v), from about 1% (w / v) to about 70% (w / v), from about 1% (w / v) to about 65% (w / v), from about 1% (w / v) to about 60% (w / v), from about 1% (w / v) to about 55% (w / v), from about 1% (w / v) to about 50% (w / v), from about 1% (w / v) to about 45% (w / v), from about 1% (w / v) to about 40% (w / v), from about 1% (w / v) to about 35% (w / v), from about 1% (w / v) to about 30% (w / v), from about 1% (w / v) to about 25% (w / v), from about 1% (w / v) to about 20% (w / v), from about 1% (w / v) to about 15% (w / v), from about 1% (w / v) to about 10% (w / v), or from about 1% (w / v) to about 5% (w / v). With the benefit of this disclosure, one of ordinary skill in the art will be able to prepare a stimulation fluid having a sufficient concentration of an aqueous base fluid for a given application.

[0043] In some optional examples, the stimulation fluids comprise nanobubbles, a water- soluble anionic polymeric scale inhibitor, and a cationic polymer or cationic macromolecule. Suitable polymeric scale inhibitors include polyacrylates, polyphosphonates, n- (phosphonomethyl) iminodiacetic acid (PMIDA), N-(carboxymethyl)-N- (phosphonomethyl)glycine, glycine, N,N'-l,2-ethanediylbis(N-(phosphonomethyl), glyphosine, aminotrimethylene phosphonic acid, sodium aminotris(methylenephosphonate), N-(2-hydroxyethyl)iminobis (methylphosphonic acid), phosphonic acid, P,P'-((2-propen-l- ylimino)bis(methylene))bis-, phosphonic acid, P,P',P"-(nitrilotris(methylene))tris-, (nitrilotris(methylene))trisphosphonic acid, ((methylimino)->dimethylene)bisphosphonic acid, phosphonic acid, P,P',P",P'”-(oxybis(2, l-ethanediylnitrilobis-i(methylene))tetrakis-, ((propylimino)bis(methylene))diphosphonic acid, phosphonic acid, P,P',P"- (nitrilotris(methylene))tris-, (ethylenedinitrilo)-tetramethylenephosphonic acid, ethylene->bis(nitrilodimethylene)tetraphosphonic acid,

[0044] (ethylenebis(nitrilobis(methylene)))tetrakisphosphonic acid, tetrasodium tetrahydrogen (ethane- 1 ,2-diylbis(nitrilobis(methylene)))tetrakisphosphonate, 6-(bis(phosphonomethyl) amino)hexanoic acid, (phenylmethyl)imino)bis(methylene)bisphosphonic acid, phosphonobutane tricarboxylic acid, 2-hydroxyphosphono dicarboxylic acid, any salts thereof, esters thereof, derivatives thereof, or any combination thereof. One of ordinary skill in the art, with the benefit of this disclosure, should be readily able to select polymeric scale inhibitor for a chosen application. The concentration of the polymeric scale inhibitor in the stimulation fluid may range from about 0.001 wt% to 10 wt% Suitable cationic polymers or macromolecules include polyquaterniun polymers, Poly(3-(trimethylaminium)-2-hydroxy-ZV,. / V-dimethyl-A- propylpran-7-aminium dichloride methacrylamide), Poly(3-(trimethylaminium)-2-hydroxy- A', dimelhyl- -propylpran- / -aminium disulfate methacrylamide), Penta-(N,N,N- trimethyl(oxiran-2-yl)methanaminium) pentachloride, or combinations thereof. For example, the concentration of the cationic polymers or macromolecules in the stimulation fluid may range from about 0.001% (w / v) to about 5% (w / v), from about 0.005 (w / v) to about 5% (w / v), from about 0.01 (w / v) to about 5% (w / v), from about 0.05 (w / v) to about 5% (w / v), from about 0.1% (w / v) to about 5% (w / v), from about 0.5% (w / v) to about 5% (w / v), from about 1% (w / v) to about 5% (w / v), from about 2% (w / v) to about 5% (w / v), from about 3% (w / v) to about 5% (w / v), or from about 4% (w / v) to about 5% (w / v). As another example, the concentration of the cationic polymers or macromolecules in a stimulation fluid may range from about 0.001% (w / v) to about 5% (w / v), from about 0.001% (w / v) to about 4% (w / v), from about 0.001% (w / v) to about 3% (w / v), from about 0.001% (w / v) to about 2% (w / v), from about 0.001% (w / v) to about 1% (w / v), from about 0.001% (w / v) to about 0.5% (w / v), from about 0.001% (w / v) to about 0.1% (w / v), from about 0.001% (w / v) to about 0.05% (w / v), from about 0.001% (w / v) to about 0.01% (w / v), or from about 0.001% (w / v) to about 0.005% (w / v). One of ordinary skill in the art, with the benefit of this disclosure, should be readily able to select a cationic polymer or macromolecule for a chosen application.

[0045] FIG. 1 illustrates a schematic of the surface and near-surface portions of a system 100 that delivers the stimulation fluid described herein to a downhole location, according to one or more examples. It should be noted that while FIG. 1 generally depicts a land-based system, it is to be recognized that like system 100 may be operated in subsea locations as well. As depicted in FIG. 1, system 100 includes a mixing tank 105, in which a stimulation fluid is formulated. The stimulation fluid may be conveyed to a pump 140 which elevates the stimulation fluid to a desired pressure to drive the stimulation fluid to wellhead 115 via line 110, where the stimulation fluid enters wellbore conduit 120. Conduit 120 extends from wellhead 115 into a wellbore 125 penetrating subterranean formation 130. Wellhead 115 is illustrated as comprising a derrick, but it is to be understood that other wellhead 115 arrangements such as a Christmas tree may be used in some examples. Wellbore 125 may be any type of wellbore including vertical, horizontal, deviated, etc. The illustrated portion of wellbore 125 is cased with a casing 135. In some alternative examples, wellbore 125 may be uncased. Upon being ejected from conduit 120, the stimulation fluid may subsequently enter into subterranean formation 130 as described in FIG. 2 below. Pump 140 is configured to raise the fluid pressure of the stimulation fluid to a desired pressure before its introduction into conduit 120. The stimulation fluid may be introduced into the wellbore 125 to increase the permeability of the subterranean formation 130 during production by reducing the amount of mud agglomeration and pore plugging that occurs in the subterranean formation 130. The stimulation fluid may be introduced into the wellbore 125 during or after drilling of the wellbore 125. The stimulation fluid may be introduced into the wellbore 125 during or after fracturing of the wellbore 125. The stimulation fluid may be introduced into the wellbore during or after performing an enhanced oil recovery operation in the wellbore 125. The stimulation fluid may be introduced into the wellbore 125 during or after performing a completion operation in the wellbore 125, such as cementing a portion of the wellbore. The stimulation fluid may be introduced into the wellbore 125 during or after a different wellbore treatment operation, such as treating the wellbore 125 with a fluid pill (e.g., a fluid loss control pill), an acidizing operation, etc.

[0046] FIG. 2 illustrates a schematic of the downhole portion of the system 100 illustrated in FIG. 1, according to one or more examples. In the example of FIG. 2, the stimulation fluid is introduced into the wellbore 125 after a fracturing fluid has been used to form one or more fractures in the subterranean formation 130. As depicted in FIG. 2, conduit 120 extends from the wellhead 115 (as illustrated in FIG. 1) into wellbore 125 penetrating subterranean formation 130. After descending through the heel 145 of the wellbore 125, the conduit 120 is coupled to one or more packers 150 positioned to isolate an interval of wellbore 125. A stimulation fluid 155, as described herein, may exit tubular 120 through openings 160. The stimulation fluid 155 may be introduced into the subterranean formation 130 via a primary fracture 165 of other such opening into the subterranean formation 130. The stimulation fluid 155 may contact the subterranean formation 130 to reduce friction and control clay accumulation within the subterranean formation 130. The stimulation fluid 155 may also contact the fracture faces or rock faces to reduce friction and control clay swell and detachment from the subterranean formation 130 upon the fracture / rock faces. In some examples, the stimulation fluid 155 may increase the adherence of subterranean clay to the rock faces, preventing pore plugging or agglomeration issues. The stimulation fluid 155 and the hydrocarbon carbon fluid may be flowed out of the wellbore 125.

[0047] It is to be recognized that system 100 is merely exemplary in nature, and various additional components may be present that have not necessarily been depicted in FIGS. 1 and 2 in the interest of clarity. Non-limiting additional components that may be present include, but are not limited to, supply hoppers, valves, condensers, adapters, joints, gauges, sensors, compressors, pressure controllers, pressure sensors, flow rate controllers, flow rate sensors, temperature sensors, and the like.

[0048] It should be clearly understood that the examples illustrated by FIGS. 1 and 2 are merely general applications of the principles of this disclosure in practice, and a wide variety of other examples are possible. Therefore, the scope of this disclosure is not limited in any manner to the details of FIGS. 1 and 2 as described herein.

[0049] FIG. 3 is a schematic showing one example of a system 200 for an injection well 205. Some portions of the injection well 205 are illustrated as uncased; however, it is to be understood that the injection well 205 may have portions that are cased or uncased as desired. A stimulation fluid 230 may be introduced into the wellbore 220 via the Christmas tree 235, or any other sufficient injection point into the wellbore 220. Although system 200 depicts a Christmas tree 235 at the wellhead, other wellhead arrangements may be used for the wellbore operation. In the illustrated example, the stimulation fluid 230 is introduced into conduit 240 to the bottom of the wellbore 220 and up through the annulus 245 where it may contact the target formation interval 210. The stimulation fluid 230 flows into the adjacent subterranean formation of the formation interval 210 to contact any hydrocarbon fluids within. The stimulation fluid 230 is not flowed back but may enter into the subterranean formation 225 at the targeted formation interval 210. The stimulation fluid 230 drives the hydrocarbon fluids into a nearby producing well also penetrating subterranean formation 225.

[0050] It should be clearly understood that the system 200 illustrated by FIG. 3 is merely a general application of the principles of this disclosure in practice, and a wide variety of other examples are possible. Therefore, the scope of this disclosure is not limited in any manner to the details of FIG. 3 as described herein.

[0051] FIG. 4 is a diagrammatic example of the charge-shielding effect of the nanobubbles 310 on fluid additives. Without the use of nanobubbles 310, coacervates 300 may form when fluid additives 301, 302 with opposite charges are contained within the same solution. Nanobubbles 310 provide a “charge-shielding” effect for the cationic and anionic components, i.e., the fluid additives 301, 302, within the stimulation fluid that mitigates the effects of hydrophobic components found in wellbores. The nanobubbles 310 may be a mixture of positively charged nanobubbles 303 and negatively charged nanobubbles 304, which shield oppositely charged fluid additive molecules 301, 302 to prevent the formation of coacervates 300. In detail, negatively charged nanobubbles 304 will shield positively, or cationically, charged fluid additives 302. Positively charged nanobubbles 303 will shield negatively, or anionically, charged fluid additives 301.

[0052] The stimulation fluids disclosed herein may directly or indirectly affect one or more components or pieces of equipment associated with or which may come into contact with the stimulation fluid s such as, but not limited to, wellbore casing, wellbore liner, completion string, insert strings, drill string, coiled tubing, slickline, wireline, drill pipe, drill collars, mud motors, downhole motors and / or pumps, cement pumps, surface-mounted motors and / or pumps, centralizers, turbolizers, scratchers, floats (e.g., shoes, collars, valves, etc.), logging tools and related telemetry equipment, actuators (e.g., electromechanical devices, hydromechanical devices, etc.), sliding sleeves, production sleeves, plugs, screens, filters, flow control devices (e.g., inflow control devices, autonomous inflow control devices, outflow control devices, etc.), couplings (e.g., electro-hydraulic wet connect, dry connect, inductive coupler, etc.), control lines (e.g., electrical, fiber optic, hydraulic, etc.), surveillance lines, drill bits and reamers, sensors or distributed sensors, downhole heat exchangers, valves and corresponding actuation devices, tool seals, packers, cement plugs, bridge plugs, and other wellbore isolation devices, or components, and the like.

[0053] Provided are stimulation fluids for treating a wellbore in accordance with the disclosure and the illustrated FIGs. An example stimulation fluid comprises an aqueous base fluid, a cationic component, an anionic component, and a nanobubble dispersion; wherein the nanobubble dispersion comprises a mixture of positively charged nanobubbles and negatively charged nanobubbles.

[0054] Additionally or alternatively, the stimulation fluid may include one or more of the following features individually or in combination. The nanobubbles in the nanobubble dispersion may comprise a mean diameter between about 50 nm to about 1000 nm. The nanobubble dispersion may be present in the stimulation fluid in a concentration of about 0.1% w / v to about 50% w / v. The nanobubbles in the nanobubble dispersion may envelop a gas selected from the group consisting of air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas, or combinations thereof. The cationic component may be selected from the group consisting of biocides, scale inhibitors, clay control additives, polymers, and surfactants. The anionic component may be selected from the group consisting of surfactants, scale inhibitors, and friction reducing polymers. The cationic component may be present in the stimulation fluid in a concentration of about 0.001% w / w to about 5% w / w. The anionic component may be present in the stimulation fluid in a concentration of about 0.001% w / w to about 2% w / w. The cationic component may be a clay control additive. The anionic component may be a friction reducing polymer. The nanobubbles in the nanobubble dispersion may have a population size of about 1 million to about 100 million per mL of the stimulation fluid.

[0055] Provided are methods for treating a wellbore with a stimulation fluid in accordance with the disclosure and the illustrated FIGs. An example method comprises introducing a stimulation fluid into a wellbore penetrating the subterranean formation, the stimulation fluid comprising: an aqueous base fluid, a cationic component, an anionic component, a nanobubble dispersion, and contacting a rock surface in the subterranean formation with the stimulation fluid; wherein the nanobubble dispersion comprises a mixture of positively charged nanobubbles and negatively charged nanobubbles.

[0056] Additionally or alternatively, the method may include one or more of the following features individually or in combination. The nanobubbles in the nanobubble dispersion may comprise a mean diameter between about 50 nm to about 1000 nm. The nanobubble dispersion may be present in the stimulation fluid in a concentration of about 0.1% w / v to about 50% w / v. The nanobubbles in the nanobubble dispersion may envelop a gas selected from the group consisting of air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas, or combinations thereof. The cationic component may be selected from the group consisting of biocides, scale inhibitors, clay control additives, polymers, and surfactants. The anionic component may be selected from the group consisting of surfactants, scale inhibitors, and friction reducing polymers. The cationic component may be present in the stimulation fluid in a concentration of about 0.001% w / w to about 5% w / w. The anionic component may be present in the stimulation fluid in a concentration of about 0.001% w / w to about 2% w / w. The cationic component may be a clay control additive. The anionic component may be a friction reducing polymer. The nanobubbles in the nanobubble dispersion may have a population size of about 1 million to about 100 million per mL of the stimulation fluid.

[0057] Provided are systems for treating a wellbore with a stimulation fluid in accordance with the disclosure and the illustrated FIGs. An example system comprises a stimulation fluid comprising: an aqueous base fluid, a cationic component, an anionic component, a nanobubble dispersion, mixing equipment configured to mix the stimulation fluid; and pumping equipment configured to pump the stimulation fluid in the wellbore; wherein the nanobubble dispersion comprises a mixture of positively charged nanobubbles and negatively charged nanobubbles.

[0058] Additionally or alternatively, the system may include one or more of the following features individually or in combination. The nanobubbles in the nanobubble dispersion may comprise a mean diameter between about 50 nm to about 1000 nm. The nanobubble dispersion may be present in the stimulation fluid in a concentration of about 0.1 % w / v to about 50% w / v. The nanobubbles in the nanobubble dispersion may envelop a gas selected from the group consisting of air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas, or combinations thereof. The cationic component may be selected from the group consisting of biocides, scale inhibitors, clay control additives, polymers, and surfactants. The anionic component may be selected from the group consisting of surfactants, scale inhibitors, and friction reducing polymers. The cationic component may be present in the stimulation fluid in a concentration of about 0.001% w / w to about 5% w / w. The anionic component may be present in the stimulation fluid in a concentration of about 0.001% w / w to about 2% w / w. The cationic component may be a clay control additive. The anionic component may be a friction reducing polymer. The nanobubbles in the nanobubble dispersion may have a population size of about 1 million to about 100 million per mL of the stimulation fluid.

[0059] The preceding description provides various examples of the systems and methods of use disclosed herein which may contain different method steps and alternative combinations of components. It should be understood that, although individual examples may be discussed herein, the present disclosure covers all combinations of the disclosed examples, including, without limitation, the different component combinations, method step combinations, and properties of the system. It should be understood that the compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps. The systems and methods can also “consist essentially of or “consist of the various components and steps. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces.

[0060] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited. In the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0061] One or more illustrative examples incorporating the examples disclosed herein are presented. Not all features of a physical implementation are described or shown in this application for the sake of clarity. Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned, as well as those that are inherent therein. The particular examples disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown other than as described in the claims below. It is therefore evident that the particular illustrative examples disclosed above may be altered, combined, or modified, and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and / or any optional element disclosed herein.

[0062] Although the present disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosure as defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A stimulation fluid for a wellbore, the stimulation fluid comprises: an aqueous base fluid, a cationic component, an anionic component, and a nanobubble dispersion comprising a plurality of nanobubbles; wherein the nanobubble dispersion comprises a mixture of positively charged nanobubbles and negatively charged nanobubbles.

2. The stimulation fluid of claim 1 , wherein the nanobubbles in the nanobubble dispersion comprise a mean diameter between about 50 nm to about 1000 nm.

3. The stimulation fluid of claim 1, wherein the nanobubble dispersion is present in the stimulation fluid in a concentration of about 0.1% w / v to about 50% w / v.

4. The stimulation fluid of claim 1, wherein the nanobubbles in the nanobubble dispersion envelop a gas selected from the group consisting of air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas, or combinations thereof.

5. The stimulation fluid of claim 1, wherein the cationic component is selected from the group consisting of biocides, scale inhibitors, clay control additives, polymers, and surfactants.

6. The stimulation fluid of claim 1, wherein the anionic component is selected from the group consisting of surfactants, scale inhibitors, and friction reducing polymers.

7. The stimulation fluid of claim 1, wherein the cationic component is present in the stimulation fluid in a concentration of about 0.001% w / w to about 5% w / w.

8. The stimulation fluid of claim 1, wherein the anionic component is present in the stimulation fluid in a concentration of about 0.001% w / w to about 2% w / w.

9. The stimulation fluid of claim 1, wherein the cationic component is a clay control additive.

10. The stimulation fluid of claim 1, wherein the anionic component is a friction reducing polymer.

11. A method for treating a subterranean formation, the method comprises: introducing a stimulation fluid into a wellbore penetrating the subterranean formation, the stimulation fluid comprising: an aqueous base fluid, a cationic component, an anionic component, a nanobubble dispersion comprising a plurality of nanobubbles, and contacting a rock surface in the subterranean formation with the stimulation fluid; wherein the nanobubble dispersion comprises a mixture of positively charged nanobubbles and negatively charged nanobubbles.

12. The method of claim 11, wherein the nanobubbles in the nanobubble dispersion comprise a mean diameter between about 50 nm to about 1000 nm.

13. The method of claim 11, wherein the cationic component is selected from the group consisting of biocides, scale control additives, clay control additives, polymers, and surfactants.

14. The method of claim 11, wherein the anionic component is selected from the group consisting of surfactants, scale inhibitors, and friction reducing polymers.

15. The method of claim 11, wherein the cationic component is a clay control additive.

16. The method of claim 11, wherein the anionic component is a friction reducing polymer.

17. The method of claim 11, wherein the nanobubbles in the nanobubble dispersion envelop a gas selected from the group consisting of air, oxygen, hydrogen, nitrogen, carbon dioxide, argon, helium, waste flue gas, ammonia, chlorine, an oxidizing gas, or combinations thereof.

18. A system for drilling a wellbore, the system comprises: a stimulation fluid comprising:an aqueous base fluid, a cationic component, an anionic component, a nanobubble dispersion comprising a plurality of nanobubbles, mixing equipment configured to mix the stimulation fluid; and pumping equipment configured to pump the stimulation fluid in the wellbore; wherein the nanobubble dispersion comprises a mixture of positively charged nanobubbles and negatively charged nanobubbles.

19. The system of claim 18, wherein the nanobubbles in the nanobubble dispersion comprise a mean diameter between about 50 nm to about 1000 nm.

20. The system of claim 18, wherein the nanobubbles in the nanobubble dispersion have a population size of about 1 million to about 100 million per mL of the stimulation fluid.