PARTICLES, COMPOSITIONS INCLUDING PARTICLES, AND METHODS FOR MAKING AND USING THE

SAME

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Application No. 62/589,180, filed November 21, 2017, the disclosure of which is incorporated by reference in its entirety herein.

BACKGROUND

Oil and natural gas can be produced from wells having porous and permeable subterranean formations. The porosity of the formation permits the formation to store oil and gas, and the permeability of the formation permits the oil or gas fluid to move through the formation. Permeability of the formation is essential to permit oil and gas to flow to a location where it can be pumped from the well. Sometimes the permeability of the formation holding the gas or oil is insufficient for the desired recovery of oil and gas. In other cases, during operation of the well, the permeability of the formation drops to the extent that further recovery becomes uneconomical. In such cases, it is common to fracture the formation and prop the fracture in an open condition using a proppant material or propping agent. The proppant material or propping agent is typically a particulate material, such as sand, resin-coated sand, and high-strength ceramic materials (e.g., sintered bauxite and ceramic beads), which are carried into the fracture by a fluid.

The most widely used proppants, sand and ceramics, exhibit some undesirable characteristics. They are typically higher in density than water, hydrophilic, and difficult to transport in low-viscosity, water-based fluids.

The treatment of proppant surfaces has been reported to address some of these difficulties, for example, in U.S. Appl. Pub. No. 2005/0244641 (Vincent); 2015/0083415 (Monroe); and 2015/0252254 (Zhang), U.S. Pat. Nos. 7,723,274 (Zhang) and 9,708,527 (Nguyen); and Int. Appl. Publ. No. WO 2015/169344 (Sujandi) and WO 2016/025044 (Nguyen).

SUMMARY

The present disclosure provides particles useful, for example, as proppants. The particles are treated to have a surface that is at least one of hydrophobic or omniphobic. The treatment is durable, easy to apply, and less expensive than other reported treatments. The present disclosure further provides a method of making the particles that is straight-forward and relatively inexpensive.

In one aspect, the present disclosure provides a particle. The particle is a sand or ceramic particle having a plurality of siloxane oligomers covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage and having free ends not bonded to the particle.

In another aspect, the present disclosure provides a particle. The particle is a sand or ceramic particle having a plurality of dialkylsiloxane oligomers covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage and having free ends not bonded to the particles. The alkyl groups of the dialkylsiloxanes independently have up to 8 carbon atoms.

In another aspect, the present disclosure provides a composition having a plurality of such particles dispersed in a fluid.

In another aspect, the present disclosure provides a method of fracturing a subterranean geological formation penetrated by a wellbore. The method includes injecting into the wellbore penetrating the subterranean geological formation a fracturing fluid at a rate and pressure sufficient to form a fracture therein and introducing into the fracture a plurality of particles described above or a composition described above.

In another aspect, the present disclosure provides a composition including particles, an acid or base accelerator, water, organic solvent, and at least one silicon-containing compound. The silicon- containing compound is independently represented by formula

R

Y - Si - Y

R or

. In these formulas, each

R is independently alkyl having up to 8 carbon atoms or phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl, each Y is independently a hydrolysable group or hydroxyl, X is alkylene having up to eight carbon atoms, m is at least 1, y is 0, 1, or 2, and p is at least 1. The particles include at least one of sand or a ceramic.

In another aspect, the present disclosure provides a process for making particles. The process includes combining components that include particles, an acid or base accelerator, water, organic solvent, and at least one silicon-containing compound. The silicon-containing compound is independently represented by formula

. In these formulas, each R is independently alkyl having up to 8 carbon atoms or phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl, each Y is independently a hydrolysable group or hydroxyl, X is alkylene having up to eight carbon atoms, m is at least 1, y is 0, 1, or 2, and p is at least 1. The particles include at least one of sand or a ceramic.

In another aspect, the present disclosure provides a coating composition that includes an acid or base accelerator, water, organic solvent, and at least one silicon-containing compound. The silicon- containing compound is independently represented by formula

. In these formulas, each

R is independently alkyl having up to 8 carbon atoms or phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl, each Y is independently a hydrolysable group or hydroxyl, X is alkylene having up to eight carbon atoms, m is at least 1, y is 0, 1, or 2, and p is at least 1.

In this application, terms such as "a", "an" and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terms "a", "an", and "the" are used interchangeably with the term "at least one". The phrases "at least one of ¹ and "comprises at least one of ¹ followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

The term "plurality" refers to more than one. In some embodiments, the plurality of particles disclosed herein comprises at least 2, 10, 100, or 1000 of such particles. The term“ceramic” as used herein refers to glasses, crystalline ceramics, glass-ceramics, and combinations thereof.

The term "polymer" refers to a molecule having a structure which essentially includes the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass. The term "polymer" encompasses oligomers.

The term "crosslink" refers to joining polymer chains together by covalent chemical bonds, usually via crosslinking molecules or groups, to form a network polymer. A crosslinked polymer is generally characterized by insolubility but may swell in the presence of certain solvents.

As used herein, the terms "alkyl" and the prefix "alk" are inclusive of both straight chain and branched chain groups and of cyclic groups, e.g., cycloalkyl. Unless otherwise specified, these groups contain from 1 to 20 carbon atoms. In some embodiments, these groups have a total of up to 10 carbon atoms, up to 8 carbon atoms, up to 6 carbon atoms, or up to 4 carbon atoms. Cyclic groups can be monocyclic or polycyclic and preferably have from 3 to 10 ring carbon atoms. It should be understood that alkyl groups are not fluorinated unless specified as such.

The term "alkylene" is the divalent or trivalent form of the "alkyl" groups defined above.

Unless otherwise indicated, the term "halogen" refers to a halogen atom or one or more halogen atoms, including chlorine, bromine, iodine, and fluorine atoms.

The term "aryl" as used herein includes carbocyclic aromatic rings or ring systems optionally containing at least one heteroatom (i.e., O, N, or S). Examples of aryl groups include phenyl, naphthyl, biphenyl, and pyridinyl.

The term "arylene" is the divalent form of the "aryl" groups defined above.

The term“hydrolysable group” refers to a group which either is directly capable of undergoing condensation reactions under appropriate conditions or which is capable of hydrolyzing under appropriate conditions to yield a compound that is capable of undergoing condensation reactions. Appropriate conditions typically refers to the presence of water and optionally the presence of acid or base.

The term“non-hydrolysable group” refers to a group generally not capable of hydrolyzing under the appropriate conditions described above for hydrolyzing hydrolyzable groups, (e.g., acidic or basic aqueous conditions).

As used herein, "a," "an," "the," "at least one," and "one or more" are used interchangeably.

The phrases "at least one of' and "comprises at least one of' followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range, including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). When the number is an integer, then only the whole numbers are included (e.g., 1, 2, 3, 4, 5, etc.).

The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. It is to be understood, therefore, that the following description should not be read in a manner that would unduly limit the scope of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawing, in which:

FIG. 1 is a schematic representation of a method of making particles and the resulting particles of the present disclosure.

DESCRIPTION

The present disclosure provides a particle having a plurality of siloxane oligomers covalently bonded to its surface. The particle is a sand or ceramic particle. The ceramic particle may be, for example, sintered bauxite, glass beads, or other particulate ceramic material. In some embodiments, the particle is a sand particle. Sand particles are available, for example, from Badger Mining Corp., Berlin, WI; Borden Chemical, Columbus, OH; Fairmont Minerals, Chardon, OH. Sintered bauxite ceramic particles are available, for example, from Borovichi Refractories, Borovichi, Russia; 3M Company, St. Paul, MN; CarboCeramics; and Saint Gobain. Glass beads are available, for example, from Diversified Industries, Sidney, British Columbia, Canada; and 3M Company. Mixtures of any of these proppants can be useful in the compositions and methods of the present disclosure. Mixtures of treated and untreated proppants may also be useful.

Typically, particles according to the present disclosure have a size in a range from 50 micrometers to 3000 micrometers (i.e., about 270 mesh to about 6 mesh (U.S. Standard Mesh)) (in some embodiments, in a range from 1000 micrometers to 3000 micrometers (i.e., about 18 mesh to about 6 mesh), 1000 micrometers to 2000 micrometers (i.e., about 18 mesh to about 10 mesh), 1000 micrometers to 1700 micrometers (i.e., about 18 mesh to about 12 mesh), 850 micrometers to 1700 micrometers (i.e., about 20 mesh to about 12 mesh), 850 micrometers to 1200 micrometers (i.e., about 20 mesh to about 16 mesh), 600 micrometers to 1200 micrometers (i.e., about 30 mesh to about 16 mesh), 425 micrometers to 850 micrometers (i.e., about 40 mesh to about 20 mesh), 300 micrometers to 600 micrometers (i.e., about 50 mesh to about 30 mesh), about 150 micrometers to 600 micrometers (i.e., about 100 mesh to about 30 mesh), about 75 micrometers to 600 micrometers (i.e., about 200 mesh to about 30 mesh), or about 50 micrometers to 600 micrometers (i.e., about 270 mesh to about 30 mesh). In some embodiments, at least 60%, 70%, 80%, or 90% by weight of the solid polymer particles have a size within one of these embodiment ranges. In some embodiments of the plurality of particles disclosed herein, any particle within the plurality of particles has a size that can be within one of these embodiment ranges. In some embodiments of the plurality of particles, substantially all of the particles in the plurality of particles can be within one of these embodiment size ranges. Substantially all can mean, for example, not more than 0.1 weight % of the particulates are larger than the larger size and not more than 2 or 1 weight % are smaller than the smaller size. The size of the particles desired may depend, for example, on the characteristics of a subterranean formation selected for a fracturing and propping operation. Particle size measurement is made by sieving the plurality of particles through a set of U.S. Standard mesh sieves.

The weight of every fraction is measured.

The shape of the particles disclosed herein is typically at least somewhat spherical although the sphericity of the particles is not critical to this disclosure. The particles disclosed herein will typically meet or exceed the standards for sphericity and roundness as measured according to American Petroleum Institute Method RP56,“Recommended Practices for Testing Sand Used in Hydraulic Fracturing

Operations”, Section 5, (Second Ed., 1995) (referred to herein as“API RP 56”). As used herein, the terms "sphericity" and "roundness" are defined as described in the API RP's and can be determined using the procedures set forth in the API RP's. In some embodiments, the sphericity of any particle in the plurality of particles is at least 0.6 (in some embodiments, at least 0.7, 0.8, or 0.9). In some embodiments, the roundness of any particle in the plurality of particles is at least 0.6 (in some embodiments, at least 0.7, 0.8, or 0.9).

The particle has a plurality of siloxane oligomers covalently bonded to its surface through at least one -Al-O-Si- or -Si-O-Si- linkage. The siloxane oligomers also have free ends, not bonded to the surface. Generally, the free ends are also not crosslinked together. In some embodiments, at least some of the siloxane oligomers comprise at least a portion independently represented by formula

, wherein each R is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, or benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, and R’ is alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl. Typically R can be a straight- chain alkyl having up to 8, 6, 5, 4, 3, or 2 atoms or branched alkyl having up to 4 or 3 atoms. In some embodiments, the siloxane oligomers are dialkylsiloxane oligomers, wherein the alkyl groups of the dialkylsiloxane oligomers independently have up to 8 carbon atoms. Typically the alkyl groups can be straight-chain alkyl having up to 8, 6, 5, 4, 3, or 2 atoms or branched alkyl having up to 4 or 3 atoms. In some embodiments, each R is methyl. In these embodiments, the siloxane oligomer is an oligomeric poly dimethyl siloxane. In formula , R’ can be a straight-chain alkyl having up to 8, 6, 5, 4, 3, or 2 atoms or branched alkyl having up to 4 or 3 atoms. In some embodiments, R’ is methyl. In some embodiments, R’ is a hydrolysable group. Examples of suitable hydrolysable groups R’ include alkoxy, acyloxy, aryloxy, hydroxyl, polyalkyleneoxy, or halogen. In some embodiments, the hydrolysable group R’ is alkoxy, acetoxy, aryloxy, or halogen. In some embodiments, the hydrolysable group R’ is alkoxy having up to 4, 3, or 2 carbon atoms, acetoxy, phenoxy, bromo, or chloro. In some embodiments, R’ is alkoxy having up to 4, 3, 2, or carbon atoms, or hydroxyl. In some embodiments, R’ is methoxy or hydroxy. Generally, R’ is not crosslinked with another oligomeric chain. In formula

, n is in a range from 3 to 500, 3 to 400, 3 to 300, 4 to 300, 5 to 300, 10 to 300, 5 to 200, 4 to 100, 4 to 50, or 3 to 20. Such values of n provide oligomers having molecular weights of up to about 40,000, 30,000, 25,000, 15,000, 10,000, 5,000, or 1,500 grams per mole. Siloxane oligomers bonded to the particles disclosed herein typically have a distribution of molecular weights. The number of repeating units and the molecular weights of oligomers can be determined, for example, by Nanowire Assisted Laser Deposition Ionization (NALDI) mass spectroscopy using techniques known to one of skill in the art. Molecular weights, particularly for higher molecular-weight materials, including number average molecular weights and weight average molecular weights, can also be measured, for example, by gel permeation chromatography (i.e., size exclusion chromatography) using techniques known to one of skill in the art.

The structure

may be directly attached to the particle through a -Al-O-Si- or -Si-O-Si- linkage. In other words, the silicon atom in having the asterisk can be included in the -Al-O-Si- or -Si-O-Si- linkage. In other embodiments, the structure

may be attached to the particle through a -Si-O-Si- that is part of another siloxane structure attached to the particle surface. The siloxane structure may arise from units at the end

of the oligomer having one or more units, wherein R and R’ are as defined above, X is alkylene having up to 8, 6, or 4 carbon atoms, Y is a hydrolyzable group including any of those described above for R’, y is 0, 1, or 2, and m is at least 1, in some embodiments, 1 to 100, 1 to 50, 1 to 25, 1 to 20, 1 to 10, 1 to 5, 2 to 100, 2 to 50, 2 to 25, 2 to 20, 2 to 15, 2 to 10, or 2 to 5. The siloxane structure may also arise from other siloxane compounds having two or more

hydrolysable groups in the molecule as described in further detail below. The siloxane structure attached to the surface of the particle may be crosslinked. For oligomeric units or compounds having hydrolysable groups, such groups can hydrolyze and react to form Al-O-Si- or -Si-O-Si- bonds with the particles or siloxane bonds with each other. However, the oligomeric siloxanes generally still have free ends that are not crosslinked. In some embodiments, at least 3, 4, 5, or 10 repeating units adjacent the free ends are not crosslinked.

The present disclosure provides a method of making particles. The method is shown

schematically in FIG. 1. The method includes combining particles 1 as described above in any of their embodiments, an acid or base accelerator, organic solvent, water, and at least one silicon-containing compound independently represented by formula The method provides particles 5 having a plurality of siloxane oligomers covalently bonded to their surfaces. It is evident from the FIG. 1 that the particle 5 is a discrete particle. That is, it is not bound together with other particles in a polymer matrix as with a filler.

As a composition useful for making particles, for example, the present disclosure also provides a composition comprising particles, an acid or base accelerator, organic solvent, water, and at least one silicon-containing compound independently represented by formula

. The present disclosure further provides a coating composition comprising an acid or base accelerator, organic solvent, water and at least one silicon-containing compound independently represented by formula

, which is useful for making particles according to some embodiments of the present disclosure. In these formulas, each R is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, or benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, and each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl. Typically, R and R’ can independently be a straight- chain alkyl having up to 8, 6, 5, 4, 3, or 2 atoms or branched alkyl having up to 4 or 3 atoms. In some embodiments, each R and R’ is methyl. Each Y is independently a hydrolysable group or hydroxyl. In some embodiments, each R’ is a hydrolysable group or hydroxyl. Examples of suitable hydrolysable groups R’ and Y include alkoxy, acyloxy, aryloxy, hydroxyl, polyalkyleneoxy, or halogen. In some embodiments, the hydrolysable group R’ or Y is alkoxy, acetoxy, aryloxy, or halogen. In some embodiments, the hydrolysable group R’ or Y is alkoxy having up to 4, 3, or 2 carbon atoms, acetoxy, phenoxy, bromo, or chloro. In some embodiments, R’ or Y is alkoxy having up to 4, 3, 2, or carbon atoms, or hydroxyl. In some embodiments, R’ or Y is methoxy or hydroxy. In formula

alkylene having up to 8, 6, or 4 carbon atoms; p is in a range from 3 to 500, 3 to 400, 3 to 300, 4 to 300, 5 to 300, 10 to 300, 5 to 200, 4 to 100, 3 to 50, or 3 to 20; m is at least 1, in some embodiments, 1 to 100, 1 to 50, 1 to 25, 1 to 20, 1 to 15, 1 to 10, 1 to 5, 2 to 100, 2 to 50, 2 to 25, 2 to 20, 2 to 15, 2 to 10, or 2 to 5; and y is 0, 1, or 2.

In some embodiments, the silicon-containing compound is dichlorodimethylsilane,

dichlorodiethylsilane, dichlorodiphenylsilane, diethoxydimethylsilane, dimethyldipropoxysilane, dibutoxydimethylsilane, dimethoxydimethylsilane, diethoxydiethylsilane, dimethoxydiphenylsilane, dibenzyldimethoxysilane, diethoxydiphenylsilane, dihexyldimethoxy silane, dimethoxydiethylsilane, or a combination thereof. Many of these compounds are commercially available. In some embodiments, the silicon-containing compound is dimethoxydimethylsilane. In some embodiments, the silicon-containing compound is

, wherein m is 1 to 15, p is in a range from 5 to 300, X is propylene or butylene, Y is methoxy, ethoxy, or hydroxyl, and y is 0, 1, or 2. In some of these embodiments, R’ is methoxy, ethoxy, or hydroxyl. In some embodiments, y is 0. Some compounds of this formula are commercially available, for example, from Siltech Corporation, Toronto, Canada, under the trade designation“SILMER TMS” in various grades. Others can be made by known methods.

The at least one silicon-containing compound may be present in the composition in a range, for example, from about 0.05, 0.1, 0.5, or 1 percent by weight to about 5, 10, 15, or 20 percent by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and at least one silicon-containing compound). In some embodiments, the at least one silicon-containing compound is present in the composition or coating composition in a range from 0.05 to 5 percent by weight, 0.1 to 5 percent by weight, or 1 to 5 percent by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and at least one silicon-containing compound).

Hydrolysis of the hydrolyzable R’ and/or Y groups (i.e., alkoxy, acyloxy, or halogen) in compounds of formula

example, typically generates silanol groups, which participate in condensation reactions to form siloxanes, for example, according to Scheme I, wherein R ¹ is alkyl, and/or covalent bonds with silanol groups (Si-OH) or aluminol groups (Al-OH) on the surface of sand or ceramic particles. Hydrolysis can occur, for example, in the presence of water optionally in the presence of an acid or base (in some embodiments, acid). Because of the potential for hydrolysis in the presence of water, for any silicon-containing compound having a hydrolyzable group in the compositions including water disclosed herein, at least a portion of the hydrolysable groups may be converted to hydroxyl groups.

Scheme I

Since the plurality of siloxane oligomers are covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage, they are not bonded to the surface of the particle through Group 4, 5, or 6 transition metal anchors. They are also not separated from the surface of the particle by a resin coating (e.g., epoxy, furan, or phenolic resin).

At neutral pH, the condensation of silanol groups may be carried out at elevated temperature (e.g., in a range from 40 °C to 200 °C or even 50 °C to 100 °C) although the reaction can also proceed at room temperature. Under acidic or basic conditions, the condensation of silanol groups may be carried out at room temperature (e.g., in a range from about 15 °C to about 30 °C or even 20 °C to 25 °C) as well as at an elevated temperature (e.g., in a range from 40 °C to 200 °C or even 50 °C to 100 °C). The rate of the condensation reaction is typically dependent upon temperature and the concentration of the silicon- containing compound.

The composition of the present disclosure and/or useful for practicing the method of making proppants disclosed herein comprises an acid or base. In some embodiments, the composition comprises acid. Useful acids include organic acids and mineral acids. In some embodiments, the acid comprises at least one of (i.e., comprises one or more of) acetic acid, citric acid, formic acid, triflic acid,

perfluorobutyric acid, sulfuric acid, or hydrochloric acid. In some embodiments, the acid is a mineral acid. In some embodiments, the acid is sulfuric acid. Stronger acids typically effect the hydrolysis of silane groups at a lower temperature than weaker acids and are therefore sometimes desirable. In some embodiments, the composition comprises base. Useful bases include amines, alkali metal hydroxides, alkaline earth metal hydroxides, and combinations thereof. Examples of suitable bases include sodium hydroxide, potassium hydroxide, sodium fluoride, potassium fluoride, and trimethylamine.

The acid or base may be present in the composition in a range, for example, from about 0.05, 0.1, 0.5, or 1 percent by weight to about 5, 10, or 15 percent by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and one or more silicon-containing compounds). In some embodiments, the acid is sulfuric acid and is present in the composition or coating composition in a range from 1 to 15 percent by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and at least one silicon-containing compound).

The water necessary for hydrolysis of silanes be added to the composition of the present disclosure or coating composition of the present disclosure that is used to coat the particles (e.g., proppants), may be adsorbed to the surface of the particles, or may be present in the atmosphere to which the at least one silicon-containing compound is exposed (e.g., an atmosphere having a relative humidity of at least 10%, 20%, 30%, 40%, or even at least 50%). Typically, to ensure that hydrolysis takes place in a convenient amount of time, the composition of the present disclosure and/or the composition useful for practicing the method of the present disclosure comprises water. In some embodiments, the water is present in the composition in a range from 0.5 percent to 50 percent (in some embodiments, 1 to 50, 2 to 50, or 10 to 50 percent) by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and at least one silicon-containing compound). Water may be added to the composition separately or may be added as part of an aqueous acidic solution or mixture with organic solvent (e.g., rubbing alcohol is 70% by weight of isopropanol in water).

The composition of the present disclosure and/or useful for practicing the method of the present disclosure includes organic solvent. As used herein, the term "organic solvent" includes a single organic solvent and a mixture of two or more organic solvents. Useful organic solvents are typically capable of dissolving at least about 0.01 percent by weight of silane represented by formula the presence of at least 2 (e.g., 10) percent by weight water and at least 1 (e.g., 5) percent by weight acid or base.

Suitable organic solvents include aliphatic alcohols having up to four carbon atoms (e.g., methanol, ethanol, isopropanol, and n-butanol); ketones (e.g., acetone, 2-butanone, and 2-methyl-4- pentanone); esters (e.g., ethyl acetate, butyl acetate, and methyl formate); ethers (e.g., diethyl ether, diisopropyl ether, methyl t-butyl ether, 2-methoxypropanol, and dipropyleneglycol monomethylether (DPM)); and hydrocarbons such as alkanes (e.g., heptane, decane, and paraffinic solvents). In some embodiments, the organic solvent is methanol, ethanol, isopropanol, or a mixture thereof. In some embodiments, the organic solvent is isopropanol.

In some embodiments, the organic solvent is present in the composition in a range from 30 percent to 98 percent (in some embodiments, 30 to 95, 30 to 90, 40 to 80, or 50 to 80 percent) by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and at least one silicon-containing compound).

In some embodiments, compositions of the present disclosure and/or useful for practicing the method of the present disclosure further comprise a crosslinker. The crosslinker is a second silicon- containing compound having at least two hydrolyzable groups, hydroxyl groups, or a combination thereof. In some embodiments, compositions of the present disclosure and/or useful for practicing the method of the present disclosure further comprise a compound represented by formula

In this formula, each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl, each Y is a hydrolysable group or hydroxyl, Q is hydrogen or alkyl having up to 4 carbon atoms; and q is at least 1. In some embodiments, q is in a range from 5 to 20, and in each of the q units, R’ is independently alkyl having up to 4 carbon atoms, and Y is alkoxy having up to 4 carbon atoms or hydroxyl. In some embodiments, in each of the q units, R’ is methyl, and Y is methoxy, ethoxy, or hydroxyl. Some of these compounds are commercially available, for example, from Evonik Industries, Toronto, Canada, under the trade designation“DYNASYLAN 9896”. Other suitable compounds of formula

which q is 1 include tetraethoxysilane, methyltrimethoxysilane, and other alkyltrialkoxysilanes. Other suitable crosslinkers include bis(methyldimethoxysilyl)ethane, 1- (triethoxysilyl)-2-(diethoxymethylsilyl)petane, bis(triethoxysilyl)ethane, and octaethoxy- 1,3,5- trisilapentane. Mixtures of these crosslinking compounds may also be useful.

The crosslinker (in some embodiments, second silicon-containing compound having at least two hydrolyzable groups, hydroxyl groups, or a combination thereof) or compound represented by formula

may be present in the composition in a range, for example, from about 0.05, 0.1, 0.5, or 1 percent by weight to about 5, 10, 15, or 20 percent by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, at least one silicon-containing compound and the crosslinker). In some embodiments, this compound is present in the composition or coating composition in a range from 0.05 to 5 percent by weight, 0.1 to 5 percent by weight, or 1 to 5 percent by weight, based on the total weight of the composition excluding particles (that is, including the weight of acid or base, water, organic solvent, and at least one silicon- containing compound). Typically, the at least one silicon-containing compound and the crosslinker are present in the composition in a ratio of up to 50:50, 75:25, or 90: 10.

The method of making the particles of the present disclosure includes combining particles as described above in any of their embodiments, an acid or base accelerator, organic solvent, water, and at least one silicon-containing compound as described above in any of its embodiments. These components can be combined, for example, at temperatures in the range from about 25 °C to about 50 °C, although temperatures outside of this range may also be useful. In some embodiments, the particles, the acid or base, the water, the organic solvent, and the at least one silicon-containing compound are combined at room temperature. In some embodiments, treating particles is carried out by first combining an acid or base, water, organic solvent, and the at least one silicon-containing compound and combining the resultant coating composition with the particles. In some embodiments, the treatment composition can be applied to the particles as a two-part composition. For example, the acid or base accelerator, water, and organic solvent may be provided as a first part, and the at least one silicon-containing compound and organic solvent may be provided as a second part. The first part and second part may sequentially be added to the particles in any order or combined immediately before adding to the particles. The treatment composition can be applied to the particles using techniques known in the art for applying

solutions/dispersions to particles (e.g., mixing the composition and particles in a vessel (in some embodiments under reduced pressure) or spraying the composition onto the particles). After application of the treatment composition to the particles, at least one of the organic solvent or water can be removed using techniques known in the art (e.g., drying the particles in an oven). Typically, about 0.1 to about 10 (in some embodiments, for example, about 0.1 to about 5 or about 0.5 to about 2) percent by weight of the composition is added to the particles, although amounts outside of this range may also be useful.

The present disclosure provides particles useful, for example, as proppants. Particles of the present disclosure and/or made by methods of the present disclosure are typically at least one of hydrophobic or omniphobic (that is, having both hydrophobic and oleophobic properties). Hydrophobic and omniphobic particles are useful, for example, in facilitating the removal of fracturing fluids that have been injected into subterranean formation, including increasing the removal rate of the fracturing fluid. Omniphobic particles can also be useful, for example, for increasing the fracture conductivity in a fractured subterranean formation, thereby increasing hydrocarbon production. While not wanting to be bound by theory, it is believed this enhanced back-production of the fracturing fluids and/or increased production of hydrocarbons is due to the siloxane oligomers altering the wettability of the proppant, thus rendering the proppant hydrophobic, oleophobic, and non-wetted by the fracturing fluids or hydrocarbons in the formation. As shown in the examples below, particles of the present disclosure and/or made by methods of the present disclosure also have a greater tendency to float in water than untreated particles. The greater tendency to float in water can allow the particles to be carried farther by a fluid into a fractured formation.

While the treatment of proppant particles with polydimethylsiloxane (PMDS) has previously been reported in U.S. Pat. Appl. Pub. Nos. 2015/252254 (Zhang) and 2005/0244641 (Vincent), we have found that commercial polydimethylsiloxanes do not provide hydrophobicity to proppant particles in a time or concentration comparable with the method disclosed herein and/or do not provide the durable hydrophobicity that is obtained for the particles of the present disclosure. As shown in Counter Examples 5 and 6, below, pre-polymerized PDMS with relatively low molecular weight does not impart hydrophobicity to sand at concentration levels where the method of the present disclosure provides hydrophobicity. We observed that the concentration of pre-polymerized PDMS necessary to impart hydrophobicity to sand is about five times higher than the minimum concentration of the composition useful in the method disclosure herein.

While lower concentrations of higher molecular weight pre-polymerized PDMS and higher concentrations of lower molecular weight pre-polymerized PDMS did provide hydrophobicity to sand, the hydrophobicity was lost when the treated sand was washed with pentane, followed by toluene and acetone or with“3M Citrus Based Cleaner”, 3M Company, St. Paul, MN, USA. In contrast, hydrophobicity of the particles of the present disclosure was maintained after washing, providing evidence that the polysiloxane oligomers disclosed herein are covalently bonded to the sand surface.

Without wanting to be bound by theory, it is believed that in-situ polymerization of compounds represented by formula

, hydroxyl terminated oligomers form, which can either bond to OH groups on the surface or can undergo further condensation to form larger chains. Since the concentration of monomeric units is limited compared to the OH functionality on the particle surface, it is more probable for an oligomer chain to find binding site on the particle rather finding another oligomer chain. This way, there can be a plurality of siloxane oligomers covalently bonded to the surface of the particle even with a very low concentration of monomer. In the case of pre -polymerized PDMS, there may be only one hydroxyl functionality present that can bond with an -OH group on the particle, which makes covalent bonding between the PDMS and the particle less likely and requires higher concentration of PDMS.

While not necessarily polymerized in situ on the surface of the particle, the silicon-containing compound represented by formula

can have multiple hydrolysable groups Y (e.g., when m is greater than 1 or at least 3) that can hydrolyze and bond to silanol or aluminol groups on the surface of the particles. The repeating m units allow these silicon-containing compounds to have a greater probability of bonding to the particle surface than pre polymerized PDMS, which may have only one hydroxyl functionality present that can bond with an -OH group on the particle.

Certain treated particles such as those disclosed in U.S. Pat. Appl. Pub. Nos. 2015/252254 (Zhang) rely on an ionic interaction between the treatment and the particle surface. For example, use cationic/betaine silane/siloxane hydrophobizing agents have been used to treat particles. The positive end of these molecules interacts with negative surface charge of sand particles, and siloxane ends render the treated particles hydrophobic and more floatable and buoyant. However, treatments that rely on such ionic interactions are partially or completely removed in the presence of salts, which may be present in fracturing fluids (see, e.g., Table B in U.S. Pat. Appl. Pub. No. 2016/0200965 (Farion et al). Particles according to the present disclosure and/or made by the method disclosed herein have siloxane oligomers covalently bonded particle surface, and as a result, render the particles floatable and buoyant in the presence of salt even at a very high concentrations.

In some embodiments, the plurality of particles disclosed herein is dispersed in a fluid. The fluid may be a carrier fluid useful, for example, for depositing proppant particles into a fracture. A variety of aqueous and non-aqueous carrier fluids can be used with the plurality of particles disclosed herein. In some embodiments, the fluid comprises at least one of water, a brine, an alcohol, carbon dioxide (e.g., gaseous, liquid, or supercritical carbon dioxide), nitrogen gas, or a hydrocarbon. In some embodiments, the fluid further comprises at least one of a surfactant, rheological modifier, salt, gelling agent, breaker, scale inhibitor, dispersed gas, or other particles.

Illustrative examples of suitable aqueous fluids and brines include fresh water, sea water, sodium chloride brines, calcium chloride brines, potassium chloride brines, sodium bromide brines, calcium bromide brines, potassium bromide brines, zinc bromide brines, ammonium chloride brines, tetramethyl ammonium chloride brines, sodium formate brines, potassium formate brines, cesium formate brines, and any combination thereof. Rheological modifiers may be added to aqueous fluid to modify the flow characteristics of the fluid, for example. Illustrative examples of suitable water-soluble polymers that can be added to aqueous fluids include guar and guar derivatives such as hydroxypropyl guar (HPG), carboxymethylhydroxypropyl guar (CMHPG), carboxymethyl guar (CMG), hydroxyethyl cellulose (HEC), carboxymethylhydroxyethyl cellulose (CMHEC), carboxymethyl cellulose (CMC), starch based polymers, xanthan based polymers, and biopolymers such as gum Arabic, carrageenan, as well as any combination thereof. Such polymers may crosslink under downhole conditions. As the polymer undergoes hydration and crosslinking, the viscosity of the fluid increases, which may render the fluid more capable of carrying the proppant. Another class of rheological modifier is viscoelastic surfactants ("VES's").

However, since particles of the present disclosure have a greater tendency to float in water than untreated particles and have a decreased critical velocity for the onset of particle removal from a sand bed than untreated particles as shown in the Examples, below, use of rheology modifiers may not be necessary. In some embodiments of the composition of the present disclosure comprising the particles disclosed herein in a fluid, the fluid is water. The fluid can be pure water, not further comprising, for example, at least one of a surfactant, rheological modifier, gelling agent, breaker, dispersed gas, or other particles. The fluid can be a brine (e.g., any of those described above), not further comprising, for example, at least one of a surfactant, rheological modifier, gelling agent, breaker, dispersed gas, or other particles. The fluid can be water substantially free of, for example, at least one of a surfactant, rheological modifier, gelling agent, breaker, dispersed gas, or other particles. As used herein, the term “substantially free of’ includes being free of any of these components and having up to 2, 1, 0.5, 0.1,

0.05, or 0.01 percent by weight of any of these components, based on the weight of the fluid. When the fluid is free of or substantially free of at least one of a surfactant, rheological modifier, or gelling agent, the composition including a plurality of the particles disclosed herein dispersed in a fluid is typically lower in cost, and the risk of damage to the formation and proppant pack is decreased.

Examples of suitable non-aqueous fluids useful for practicing the present disclosure include alcohols (e.g., methanol, ethanol, isopropanol, and other branched and linear alkyl alcohols); diesel; raw crude oils; condensates of raw crude oils; refined hydrocarbons (e.g., gasoline, naphthalenes, xylenes, toluene and toluene derivatives, hexanes, pentanes, and ligroin); natural gas liquids; gases (e.g., carbon dioxide and nitrogen gas); liquid carbon dioxide; supercritical carbon dioxide; liquid propane; liquid butane; and combinations thereof. Some hydrocarbons suitable for use as such fluids can be obtained, for example, from SynOil, Calgary, Alberta, Canada under the trade designations "PLATINUM", "TG-740", "SF-770", "SF-800", "SF-830", and "SF-840". Mixtures of the above non-aqueous fluids with water (e.g., mixtures of water and alcohol or several alcohols or mixtures of carbon dioxide (e.g., liquid carbon dioxide) and water) may also be useful for practicing the present disclosure. Mixtures can be made of miscible or immiscible fluids. Rheological modifiers (e.g., a phosphoric acid ester) can be useful in non- aqueous fluids as well. In some of these embodiments, the fluid further comprises an activator (e.g., a source of polyvalent metal ions such as ferric sulfate, ferric chloride, aluminum chloride, sodium aluminate, and aluminum isopropoxide) for the gelling agent.

Fluid containing a plurality of particles according to the present disclosure dispersed therein can also include at least one breaker material (e.g., to reduce viscosity of the fluid once it is in the well). Examples of suitable breaker materials include enzymes, oxidative breakers (e.g., ammonium

peroxydisulfate), encapsulated breakers such as encapsulated potassium persulfate (e.g., available, for example, under the trade designation "ULTRAPERM CRB" or“SUPERULTRAPERM CRB”, from Baker Hughes), and breakers described in U. S. Pat. No. 7,066,262 (Funkhouser).

Fluids having a plurality of particles according to the present disclosure dispersed therein may also be foamed. In these embodiments, the fluid further comprises dispersed gas. Suitable gases include nitrogen, air, carbon dioxide, propane, helium, argon, and methane. Foamed fluids may contain, for example, nitrogen, carbon dioxide, or mixtures thereof at volume fractions ranging from 10% to 90% of the total fluid volume.

Fluids including a plurality of particles of the present disclosure can also contain a surfactant. Surfactants can be useful, for example, for stabilizing the foam described above and may also be referred to as foaming agents. Suitable foaming agents include cationic foaming agents, anionic foaming agents, amphoteric foaming agents, nonionic foaming agents, and combinations thereof. Specific examples of suitable foaming agents include surfactants like betaines, sulfated or sulfonated alkoxylates, alkyl quaternary amines, alkoxylated linear alcohols, alkyl sulfonates, alkyl aryl sulfonates, C10-C20 alkyldiphenyl ether sulfonates, polyethylene glycols, ethers of alkylated phenol, sodium dodecylsulfate, alpha olefin sulfonates such as sodium dodecane sulfonate, trimethyl hexadecyl ammonium bromide, and combinations thereof. Foaming agents may be included in foamed fluids at concentrations ranging typically from about 0.05% by weight to about 2% by weight, based on the total weight of the liquid components.

Particles of the present disclosure and/or made by the method of the present disclosure may be used in combination with other particles, for example, in the fluids and method of fracturing described herein. The other particles may be conventional proppant materials such as at least one of resin-coated sand, graded nut shells, resin-coated nut shells, particulate thermoplastic materials, and combinations thereof.

The particles and fluids described above, in any of their embodiments, may be useful, for example, for practicing the method of fracturing a subterranean geological formation penetrated by a wellbore according to the present disclosure. Techniques for fracturing subterranean geological formations comprising hydrocarbons are known in the art, as are techniques for introducing proppants into the fractured formation to prop open fracture openings. In some methods, a fracturing fluid is injected into the subterranean geological formation at rates and pressures sufficient to open a fracture therein. When injected at the high pressures exceeding the rock strength, the fracturing fluid opens a fracture in the rock. The fracturing fluid may be an aqueous or non-aqueous fluid having any of the additives described above. Particles of the present disclosure and/or made by the method of the present disclosure can be included in the fracturing fluid. That is, in some embodiments, injecting the fracturing fluid and introducing the plurality of particles are carried out simultaneously. In other embodiments, the plurality of particles disclosed herein may be present in a second fluid (described in any of the above embodiments) that is introduced into the well after the fracturing fluid is introduced. As used herein, the term "introducing" (and its variants“introduced”, etc.) includes pumping, injecting, pouring, releasing, displacing, spotting, circulating, or otherwise placing a fluid or material (e.g., proppant particles) within a well, wellbore, fracture or subterranean formation using any suitable manner known in the art. The plurality of particles according to the present disclosure can serve to hold the walls of the fracture apart after the pumping has stopped and the fracturing fluid has leaked off or flowed back. The plurality of particles according to the present disclosure may also be useful, for example, in fractures produced by etching (e.g., acid etching). Fracturing may be carried out at a depth, for example, in a range from 500 to 8000 meters, 1000 to 7500 meters, 2500 to 7000 meters, or 2500 to 6000 meters. In some embodiments, fracturing is carried out at a temperature in a range from 60 °C to 150 °C, in some embodiments, 100 °C to 150 °C. In some embodiments, after fracturing, the fracture has a closure pressure greater than 55 MPa (8000 psi). These depths may correspond, for example, to closure pressures in a range from 500 psi to 15,000 psi (3.4 x 10 ⁷ Pa to 1.0 x 10 ⁸ Pa), in some embodiments, at least 8000 psi (5.5 x 10 ⁷ Pa).

The fluid carries particles into the fractures where the particles are deposited. If desired, particles might be color coded and injected in desired sequence such that during transmission of subject fluid therethrough, the extracted fluid can be monitored for presence of particles. The presence and quantity of different colored particles might be used as an indicator of what portion of the fractures are involved as well as indicate or presage possible changes in transmission properties. Typically, after introducing the plurality of the particles into the fracture, the fracture has a conductivity that is higher than a comparative fracture, wherein the comparative fracture is the same as the fracture except that it includes a plurality of sand or ceramic particles that do not have the plurality of siloxane oligomers covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage and free ends not bonded to the particle. In some embodiments, the conductivity of the fracture is at least 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 percent higher than the conductivity of the comparative fracture. When the comparative fracture is said to be the same as the fracture, it is meant that the fracture and the comparative fracture have the same volume, include the same volume and size of particles, and are made from the same subterranean rock (e.g., sandstone or limestone). The same sand or ceramic is used for the plurality of particles introduced into the fracture except that in the comparative fracture, the particles are not treated as described herein. As shown in Table 16 in the Examples below, the conductivity of a fracture including a plurality of the particles disclosed herein is higher than the conductivity of a fracture including untreated sand when either water or oil was flowed through the fracture.

In some embodiments of the method of the fracturing a subterranean formation, the method further comprises obtaining (e.g., pumping or producing) hydrocarbons from the subterranean geological formation after introducing into the fracture the plurality of the particles. The rate of production of hydrocarbons is typically higher for particles of the present disclosure than for comparative, untreated particles.

The method of making particles according to the present disclosure can be readily carried out at the site of a fracturing operation. However, in many cases it may be more practical to treat the particles at a different location and transport them to the site of a fracturing operation.

Water (e.g., brine) may be present in a subterranean geological formation comprising

hydrocarbons and may cause hydrolysis of hydrolysable groups on the at least one silicon-containing compound (and cause condensation to provide a siloxane). Thus, combining the particles, acid or base, organic solvent, and the at least one silicon-containing compound may be carried out during the injection of particles into a fracture of the formation, and making the particles of the present disclosure may be carried out downhole.

Some Embodiments of the Disclosure

In a first embodiment, the present disclosure provides a particle comprising:

a sand or ceramic particle; and

a plurality of siloxane oligomers covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage and having free ends not bonded to the particle.

In a second embodiment, the present disclosure provides the particle of the first embodiment, wherein the plurality of siloxane oligomers comprises oligomers having portions independently represented by formula , wherein:

each R is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, or benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms,

R’ is alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl; and

n is in a range from 3 to 500.

In a third embodiment, the present disclosure provides the particle of the second embodiment, wherein each R is alkyl having up to 4 carbon atoms.

In a fourth embodiment, the present disclosure provides the particle of the third embodiment, wherein the plurality of siloxane oligomers comprises oligomers having polydimethylsiloxane portions.

In a fifth embodiment, the present disclosure provides a particle comprising:

a sand or ceramic particle; and

a plurality of dialkylsiloxane oligomers covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage and having free ends not bonded to the particle, wherein the alkyl groups of the dialkylsiloxanes independently have up to 8 carbon atoms.

In a sixth embodiment, the present disclosure provides the particle of the fifth embodiment, wherein each of dialkylsiloxane oligomers is a dimethylsiloxane oligomer.

In a seventh embodiment, the present disclosure provides the particle of any one of the first to sixth embodiments, wherein the particle is a sand particle.

In an eighth embodiment, the present disclosure provides the particle of any one of the first to seventh embodiments having a size in a range from 50 micrometers to 3000 micrometers.

In a ninth embodiment, the present disclosure provides a composition comprising a plurality of the particles of any one of the first to eighth embodiments, dispersed in a fluid.

In a tenth embodiment, the present disclosure provides the composition of the ninth embodiment, further comprising gas.

In an eleventh embodiment, the present disclosure provides the composition of the ninth or tenth embodiment, wherein the fluid comprises water.

In a twelfth embodiment, the present disclosure provides the composition of any one of the ninth to eleventh embodiments, further comprising at least one of a surfactant, rheological modifier, salt, gelling agent, breaker, or scale inhibitor. In a thirteenth embodiment, the present disclosure provides the composition of the eleventh embodiment, wherein the fluid is substantially free of at least one of a surfactant, rheological modifier, gelling agent, or breaker.

In a fourteenth embodiment, the present disclosure provides a method of fracturing a subterranean geological formation penetrated by a wellbore, the method comprising:

injecting into the wellbore penetrating the subterranean geological formation a fracturing fluid at a rate and pressure sufficient to form a fracture therein; and

introducing into the fracture a plurality of the particles of any one of the first to eighth embodiments or the composition of any one of the ninth to thirteenth embodiments.

In a fifteenth embodiment, the present disclosure provides the method of the fourteenth embodiment, wherein injecting the fracturing fluid and introducing the plurality of particles are carried out simultaneously, and wherein the fracturing fluid comprises the plurality of particles.

In a sixteenth embodiment, the present disclosure provides the method of the fourteenth embodiment, wherein introducing the plurality of particles is subsequent to injecting the fracturing fluid.

In a seventeenth embodiment, the present disclosure provides the method of any one of the fourteenth to sixteenth embodiments, wherein after introducing the plurality of the particles into the fracture, the fracture has a conductivity that is at least five percent higher than a comparative fracture, wherein the comparative fracture is the same as the fracture except that it includes a plurality of sand or ceramic particles that do not have the plurality of siloxane oligomers covalently bonded at one end to the surface of the particle by at least one -Al-O-Si- or -Si-O-Si- linkage and having free ends not bonded to the particle.

In an eighteenth embodiment, the present disclosure provides the method of any one of the fourteenth to seventeenth embodiments, further comprising obtaining (e.g., pumping or producing) hydrocarbons from the wellbore after introducing into the fracture the plurality of the particles.

In a nineteenth embodiment, the present disclosure provides a composition comprising particles, an acid or base accelerator, water, organic solvent, and at least one silicon-containing compound independently represented by formula

, or a combination thereof,

wherein

each R is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, or benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms;

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is independently a hydrolysable group or hydroxyl;

X is alkylene having up to eight carbon atoms;

m is at least 1 ;

y is 0, 1, or 2; and

p is at least 1,

wherein the particles comprise at least one of sand or a ceramic.

In a twentieth embodiment, the present disclosure the composition of the nineteenth embodiment, wherein the accelerator is an acid.

In a twenty -first embodiment, the present disclosure provides the composition of the twentieth embodiment, wherein the accelerator is a mineral acid.

In twenty-second embodiment, the present disclosure provides the composition of any one of the nineteenth to twenty -first embodiments, wherein the organic solvent is an alcohol having up to 4 carbon atoms.

In a twenty -third embodiment, the present disclosure provides the composition of the twenty- second embodiment, wherein the organic solvent is isopropanol.

In a twenty -fourth embodiment, the present disclosure provides the composition of any one of the nineteenth to twenty-third embodiments, further comprising a silicon-containing crosslinking compound having at least two or three hydrolysable groups.

In a twenty -fifth embodiment, the present disclosure provides the composition of any one of the nineteenth to twenty -third embodiments, further comprising a compound represented by formula , wherein

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is a hydrolysable group or hydroxyl;

Q is hydrogen or alkyl having up to 4 carbon atoms; and

q is at least 1.

In a twenty-sixth embodiment, the present disclosure provides the composition of the twenty-fifth embodiment, wherein q is in a range from 5 to 20, and wherein in each of the q units R’ is independently alkyl having up to 4 carbon atoms, and Y is alkoxy having up to 4 carbon atoms or hydroxyl.

In a twenty-seventh embodiment, the present disclosure provides a method of making particles, the method comprising making the composition of any one of the nineteenth to twenty-sixth

embodiments.

In a twenty -eighth embodiment, the present disclosure provides a method of making particles, the method comprising combining components comprising particles, an acid or base accelerator, water, organic solvent, and at least one silicon-containing compound independently represented by formula

or a combination thereof,

wherein

each R is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, or benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms; each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is independently a hydrolysable group or hydroxyl;

X is alkylene having up to eight carbon atoms;

m is at least 1 ;

y is 0, 1, or 2; and

p is at least 1,

wherein the particles comprise at least one of sand or a ceramic.

In a twenty -ninth embodiment, the present disclosure provides the method of the twenty-eighth embodiment, wherein combining components comprises first combining an acid or base accelerator, water, organic solvent, and the at least one silicon-containing compound and combining the resultant mixture with the particles.

In a thirtieth embodiment, the present disclosure provides the method of the twenty-eighth or twenty-ninth embodiment, wherein the accelerator is an acid.

In a thirty-first embodiment, the present disclosure provides the method of the thirtieth embodiment, wherein the accelerator is a mineral acid.

In a thirty-second embodiment, the present disclosure provides the method of any one of the twenty-eighth to thirty-first embodiments, wherein the organic solvent is an alcohol having up to 4 carbon atoms.

In a thirty-third embodiment, the present disclosure provides the method of the thirty-second embodiment, wherein the organic solvent is isopropanol.

In a thirty-fourth embodiment, the present disclosure provides the method of any one of the twenty-eighth to thirty-third embodiments, wherein the components further comprise a silicon-containing crosslinking compound having at least two or three hydrolysable groups.

In a thirty-fifth embodiment, the present disclosure provides the method of any one of the twenty- eighth to thirty -third embodiments, wherein the components further comprise a compound represented by formula

, wherein

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is a hydrolysable group or hydroxyl;

Q is hydrogen or alkyl having up to 4 carbon atoms; and

q is at least 1.

In a thirty-sixth embodiment, the present disclosure provides the method of the thirty-fifth embodiment, wherein q is in a range from 5 to 20, and wherein in each of the q units R’ is independently alkyl having up to 4 carbon atoms, and Y is alkoxy having up to 4 carbon atoms or hydroxyl.

In a thirty-seventh embodiment, the present disclosure provides the method of any one of the twenty-seventh to thirty-sixth embodiments, wherein the particles, the acid or base accelerator, the water, the organic solvent, and the at least one silicon-containing compound are combined at room temperature.

In a thirty-eighth embodiment, the present disclosure provides the method of any one of the twenty-seventh to thirty-seventh embodiments, further comprising removing the organic solvent.

In a thirty-ninth embodiment, the present disclosure provides the composition or method of any one of the nineteenth to thirty-eighth embodiments, wherein the silicon-containing compound is dimethoxydimethylsilane .

In a fortieth embodiment, the present disclosure provides the composition or method of any one of the nineteenth to thirty-eighth embodiments, wherein the silicon-containing compound is

wherein

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is a hydrolysable group or hydroxyl;

X is alkylene having up to eight carbon atoms;

y is 0, 1, or 2;

m is up to 15; and

p is in a range from 5 to 300.

In a forty -first embodiment, the present disclosure provides the composition or method of any one of the nineteenth to fortieth embodiments, wherein the particles comprise sand. In a forty-second embodiment, the present disclosure provides the composition or method of any one of the nineteenth to forty-first embodiments, wherein the particles have a size in a range from 50 micrometers to 3000 micrometers.

In a forty-third embodiment, the present disclosure provides a coating composition comprising an acid or base accelerator, water, an organic solvent, and at least one silicon-containing compound independently represented by formula

wherein

each R is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, or benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms;

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is a hydrolysable group or hydroxyl;

X is alkylene having up to eight carbon atoms;

n is at least 1;

y is 0, 1, or 2; and

p is at least 1.

In a forty -fourth embodiment, the present disclosure provides the coating composition of the forty-third embodiment, wherein the accelerator is an acid.

In a forty -fifth embodiment, the present disclosure provides the coating composition of the forty- fourth embodiment, wherein the accelerator is a mineral acid.

In a forty-sixth embodiment, the present disclosure provides the coating composition of any one of the forty-third to forty -fifth embodiments, wherein the organic solvent is an alcohol having up to 4 carbon atoms.

In a forty-seventh embodiment, the present disclosure provides the coating composition of any one of the forty-third to forty-sixth embodiments, wherein the organic solvent is isopropanol.

In a forty -eighth embodiment, the present disclosure provides the coating composition of any one of forty-third to forty-seventh embodiments, further comprising a silicon-containing crosslinking compound having at least two hydrolysable groups. In a forty -ninth embodiment, the present disclosure provides the coating composition of any one of forty-third to forty-eighth embodiments, further comprising a compound represented by formula R’,

wherein

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is a hydrolysable group or hydroxyl;

Q is hydrogen or alkyl having up to 4 carbon atoms; and

q is at least 1.

In a fiftieth embodiment, the present disclosure provides the coating composition of the forty- ninth embodiment, wherein q is in a range from 5 to 20, and wherein in each of the q units R’ is independently alkyl having up to 4 carbon atoms, and Y is alkoxy having up to 4 carbon atoms or hydroxyl.

In a fifty-first embodiment, the present disclosure provides the coating composition of any one of the forty-third to fiftieth embodiments, wherein the silicon-containing compound is

wherein

each R’ is independently alkyl having up to 8 carbon atoms, phenyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, benzyl that is unsubstituted or substituted by at least one alkyl or alkoxy having up to 4 carbon atoms, a hydrolysable group, or hydroxyl;

each Y is a hydrolysable group or hydroxyl;

X is alkylene having up to eight carbon atoms;

y is 0, 1, or 2;

m is up to 15; and

p is in a range from 5 to 300. In order that this disclosure can be more fully understood, the following examples are set forth. It should be understood that these examples are for illustrative purposes only and are not to be construed as limiting this disclosure in any manner. EXAMPLES

All materials are commercially available, for example from Sigma-Aldrich Chemical Company, Milwaukee, WI, USA, or known to those skilled in the art, unless otherwise stated or apparent.

The following abbreviations are used in this section: mL=milliliters, g=grams, kg=kilograms, lb=pounds, cm=centimeters, mm=millimeters, pm=micrometers, mil=thousandths of an inch, wt%= percent by weight, min=minutes, h=hours, d=days, N=newtons, NMR=nuclear magnetic resonance, ppm=parts per million, eq=equivalent. Abbreviations for materials used in this section, as well as descriptions of the materials, are provided in Table 1.

Table 1. Materials

Preparative Examples

For Preparative Example 1 (PE-l) through Preparative Example 6 (PE-6), 1.0 g of H2SO4 was mixed with the amount of an alcohol, and water in the case of PE-6, as indicated in Table 2, resulting in generation of heat. When the mixture reached room temperature, an amount of DMDMS or PDMS indicated in Table 2 was added to the mixture. For Preparative Examples 7 and 8, the PDMS was mixed with rubbing alcohol in the amounts indicated in Table 2, and no H2SO4 was added. After mixing, the solution was allowed to stand at room temperature for 30 min before being used for sand treatment. Table 2. Compositions for PE-l through PE-8

For Preparative Example 9 (PE-9) through Preparative Example 11 (PE-l 1), the components indicated in Table 3 were dissolved in 9.0 g isopropanol at room temperature.

Table 3. Compositions for PE-9 through PE- 11

Sand treatment procedures

For Examples 1 through 48 and Counter Examples 1 to 6, 100 g of the sand indicated in Tables 4 through 10 was placed into a 250-mL plastic or glass jar and then an amount of treatment solution was added to the sand using a l-mL syringe with 27Gx 1/2” (1.27 cm) needle, as indicated in Tables 4 through 10. Afterwards, the sand was swirled for 30 seconds and disposed into an aluminum plate and swirled 8 to 10 times.

For Examples 49 through 51, a mixture of 0.2 g of a 10 wt% H2SO4 solution in DI water and 0.2 g of treatment solution indicated in Table 11 was added to 100 g of sand placed in a 250-mL plastic or glass jar using a 5-mL syringe attached with 27Gx 1/2” (1.27 cm) needle. Afterwards, the sand was swirled for 1 min and poured into an aluminum plate and swirled approximately 8 to 10 times.

For Counter Example 7 (CE-7), untreated sand was used. Floatability measurements

For Examples 1 through 48, 52, and Counter Examples 1 to 7, the floatability was determined by adding water into a pre-weighed sand sample, decanting the treated sand that floated with water and repeating several times until adding water did not result in additional floating sand. The difference between initial weight of the sand and the residual sand that was not carried by water was used to calculate the floatability of the sand, presented in Tables 4 through 10. For example, if 100 g of treated sand was tested by this procedure, and 90 g of treated sand was removed with decanted water, the floatability would be (90 g sand removed / 100 g initial sand mass) * 100 = 90%.

For Examples 49 through 51, the floatability of the sand was determined by adding 50 g of sand and approximately 1 to 2 mL of 5% aqueous solution of“POLYFROTH” floatation frother into 100 g of water in a l25-mL glass bottle. The glass bottle was gently shaken for 1 min and then the sand that floated was decanted. The difference between initial weight of the sand and the residual sand that was not decanted was used to calculate the floatability of the sand, presented in Table 11.

Hydrophobicity measurement

For Examples 1 through 52 and Counter Examples 1 to 7, the hydrophobicity was demonstrated by applying water to the surface of the treated sand, observing whether the water formed beads on the sand surface, and recording the time from application of treatment to the observation of beads. For omniphobicity, the same procedure was followed, but with application of a 70:30 waterisopropanol mixture to the treated sand. The following procedure was used. Three minutes after application of treatment solution, when used, a drop of water or a 70/30 mixture of water/isopropanol was placed onto the sand to determine hydrophobicity and omniphobicity, respectively. If the liquid beaded up on the surface of the sand, the time was recorded and the evaluation was stopped. If the liquid did not bead up on the surface of the sand, another drop of water or 70/30 water/isopropanol was placed on the sand after one additional minute. The procedure was repeated each additional minute until hydrophobicity or omniphobicity was observed. The data is presented in Tables 4 to 11 as the time between the addition of the treatment solution to the sand and time when beading of the liquid on the sand was observed.

Salt compatibility measurement

Examples 49 to 51 were repeated three times to provide 450 g of treated sand for each Example. An amount of salt (NaCl, KC1, or CaCh-2H ₂ 0) indicated in Table 13 was added to a glass bottle containing 50 g of treated sand and approximately 1 to 2 mL of 5% aqueous solution of“POLYFROTH” floatation frother in 100 mL of DI water. After salt addition, the bottle was shaken gently for 2 min. Observed changes in floatability of the treated sand was recorded in Table 10. Polysiloxane to substrate bonding measurement

For Example 52, the procedure of Example 5 was repeated with the modification that 0.4 g of Preparative Example 3 was used to treat 100 g of 20/40 Wisconsin White Silica sand. The time to observe hydrophobicity was 3 to 4 minutes. 20 g of the treated sand was either washed three times each with 20 mL of n-pentane, toluene, and acetone, or washed with Citrus Cleaner. The sand was then dried in an oven at 80 °C. When dry, the hydrophobicity of the sand was tested by placing water droplets on the sand and observing whether the water beaded up on the sand. For comparison, 20 g of the treated sand made as a repeat of Counter Example 4 was also washed, dried, and evaluated using the same procedure. The results of this measurement for Example 52 and Counter Example 4 are presented in Table 13.

NALDI mass spectrometry

Nanowire assisted laser desorption ionization time of flight (NALDI-TOF) mass spectrometry in an instrument available under the trade designation“ULTRAFLEXTREME” from Bruker Daltronics Inc., Billerica, MA, USA, was used to determine molecular weight of some polymer fragments from preparative examples PE-3, PE-6 and PE-8. Samples were mixed in a matrix of a 10 mg/mL solution of DCTB in dichloromethane and a solution of NaCl in dichloromethane. Results are presented in Table 14. For PE-3, PE-6 and PE-8, peaks were observed between the lower m/z and the higher m/z reported in the table at m/z intervals of approximately 74 mass units. The Lower and Higher observed m/z peaks were the lowest and highest m/z peaks identified, respectively, in the scanned m/z range, in a series of peaks separated at intervals of approximately 74 mass units. Thus, NALDI mass spectrometry provides evidence of polymerization.

Critical velocity to initiate particle movement

Sand beds of treated and untreated sand of varying sizes were deposited in a horizontal conduit by using turbulent flow of water to determine critical velocity for particle movement from the bed deposits. A detailed description of the apparatus used and the measurement procedure can be found on pages 131 to 133 of Corredo, Bizhani and Kura; Journal of Petroleum Science and Engineering. 147 (2016), 129-142. Canadian brown sand samples, obtained from Sil Industrial Minerals, Canada, were treated with PE- 10, applied to sand using a clean cement mixing tub loaded with sand particles. Coating was applied using a 20 mL syringe and after the coating was sprayed, sand particles were tumbled for 15-20 min. Afterwards, treated sand was collected in a plastic pail and left room temperature for 3 days in order to evaporate the solvent. 20/40, 30/50 and 40/70 particles were treated with 6.0 g of PE-10 mixed with 6.0 g of 10% H2SO4 solution in water for 1.0 kg of sand while 100 mesh particles were treated with a mixture of 14.0 g of PE- 10 and 14.0 g of 10% H2SO4 solution in water for 1.0 kg of sand. The experimental procedure consisted of two stages. The first stage was establishment of the sand particle bed; the second stage was transport fluid circulation over the sand particle bed at increasing velocity, with determination of the critical velocity for particle movement determined by recording with video cameras. Details of the measurement procedure are as described in Corredo, et. al., page 133. Results are presented in Table 15.

Conductivity measurement

A fracture conductivity cell was used to measure conductivity for brine and oil of packs of samples of sand subjected to closure stress and temperature over extended time according to ISO 13503- 5, 2006,“Procedures for Measuring the Long-Term Conductivity of Proppants.” Fluids were pumped through the packs and from differential pressure measurements between the inlet and outlet of each pack, the conductivity of the pack was determined. Flow was generated and maintained by a piston pump located downstream of the cell. The pump can control flow rates down to 10 ⁵ cmVmin with a resolution of 2 mm ³ . 2.0 g of PE-10 and 2.0 g of 10% H ₂ SO ₄ solution in water was applied on 1 kg of 20/40 sand placed in a 1200 mL plastic bottle. The bottle was capped and shaken to ensure homogeneous mixing of coating on the sand surface. After mixing, the bottle cap was kept open for 24 h to allow evaporation of solvent. Treated sand samples were passed through 20/40 mesh sieve to eliminate any larger or smaller particles.

The test procedure was as follows:

1. Ohio sandstone was used. Ohio sandstone has a static elastic modulus of approximately 4 million- psi (257579 MPa) and a permeability of 0.1 mD (9.9xlO ^-10 m ² ). Sandstone wafers were machined to thickness 9.5±0.05 mm and one rock was placed in the conductivity cell.

2. The selected proppant was sample split and weighed out. Sample splitting ensured that a representative sample was achieved in terms of its particle size distribution.

3. The proppant was placed into the cell and levelled. The top rock was then inserted.

4. Heated steel platens provided the correct temperature simulation for the test. A thermocouple inserted in the middle port of the cell wall recorded the temperature of the pack. A servo-controlled loading ram provided the closure stress.

5. A 70 mbar full range differential pressure transducer was activated by closing the bypass valve and opening the low pressure line valve (the purpose of the second valve was to prevent fluid flow bypassing the cell itself while the d.p. bypass was open).

6. The cells were initially set at 20 °C and 1000 psi (6895 kPa). The cells were then heated to 50 °C and held for 15 hours at 1000 psi (6895 kPa) before being ramped to 2000 psi (13789 kPa) over 10 minutes. After 50 hours, a set of measurements was made. Further measurements were made until the measured pressure differential was stable.

7. Fluid was pumped at rates as specified by the ISO standard. When the differential pressure was stable, data was logged every second for a 3 -minute interval. The output from the differential pressure transducer was recorded by a data logging, 5-digit resolution multi-meter.

8. The mean value of the differential pressure was retrieved from the multi-meter together with the peak high and low values. If the difference between the high and low values was greater than the 5% of the mean, the data was disregarded. Temperature was recorded from the inline thermocouple at the start and end of the flow test period. If the temperature variation was greater than 0.5 degrees K the test was disregarded. Viscosity of the fluid as obtained from using the measured temperature and viscosity tables. For brine at 100 psi (689 kPa), no pressure correction was made. The density of brine at elevated temperature was obtained from these tables. At least three permeability determinations were made at each set of conditions. If the standard deviation of the determined permeabilities was not less than 1% of the mean value for the test sequence, the results were not considered acceptable.

9. Mineral oil was pumped under various conditions. Oil was flowed at 1 mL/min for 1 to 2 hours until the pressure drop across the pack stabilized. During this process, the effluent was retained, and its water content was measured. The fracture conductivity to the oil was determined from published viscosity tables using Darcy’s equation.

10. Further measurements were made at 4000 and 6000 psi (27579 and 41368 kPa).

Conductivity measurement results are presented in Table 16.

Table 4. Results of hydrophobicity and floatability measurements of treated 20/40 Wisconsin White Silica sand

N/O = Not Observed. The sand was not observed to become hydrophilic or omniphobic or to float. Table 5. Results of hydrophobicity and floatability measurements of treated 30/50 Wisconsin White Silica sand

Table 6. Results of hydrophobicity and floatability measurements of treated 40/70 Brady Brown sand

Table 7. Results of hydrophobicity and floatability measurements of treated 100 mesh Brady Brown sand

Table 8. Results of hydrophobicity and floatability measurements of treated 100 mesh Wisconsin White Silica sand

Table 9. Results of hydrophobicity and floatability measurements of treated 20/40 ceramic proppant

Table 10. Results of hydrophobicity and floatability measurements of treated 30/50 ceramic proppant

Table 11. Results of hydrophobicity and floatability measurements of treated 20/40 Wisconsin White Silica sand

N/A = Not Applicable

N/O = Not Observed

Table 12. Results of Polysiloxane to Substrate Bonding Measurement for 20/40 Wisconsin White Silica sand

Table 13. Salt Compatibility Results, 0.2 g of coating per 100 g of 20/40 Wisconsin White Silica Sand

Table 14.

Table 15. Critical velocity for particle movement for treated and untreated particles

Table 16. Conductivity of treated samples and untreated samples at different pressures

This disclosure may take on various modifications and alterations without departing from its spirit and scope. Accordingly, this disclosure is not limited to the above-described embodiments but is to be controlled by the limitations set forth in the following claims and any equivalents thereof. This disclosure may be suitably practiced in the absence of any element not specifically disclosed herein.