Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/60—Compositions for stimulating production by acting on the underground formation
  • C09K8/62—Compositions for forming crevices or fractures
  • C09K8/66—Compositions based on water or polar solvents
  • C09K8/68—Compositions based on water or polar solvents containing organic compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/2805—Compounds having only one group containing active hydrogen
  • C08G18/288—Compounds containing at least one heteroatom other than oxygen or nitrogen
  • C08G18/2885—Compounds containing at least one heteroatom other than oxygen or nitrogen containing halogen atoms
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/2805—Compounds having only one group containing active hydrogen
  • C08G18/288—Compounds containing at least one heteroatom other than oxygen or nitrogen
  • C08G18/289—Compounds containing at least one heteroatom other than oxygen or nitrogen containing silicon
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/60—Compositions for stimulating production by acting on the underground formation
  • C09K8/80—Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open

Definitions

• 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.
• the permeability of the formation holding the gas or oil is insufficient for the desired recovery of oil and gas.
• the permeability of the formation drops to the extent that further recovery becomes uneconomical.
• the proppant material or propping agent is typically a particulate material, such as sand and (man-made) engineered proppants, such as resin coated sand and high-strength ceramic materials (e.g., sintered bauxite, crystalline ceramic bubbles, and ceramic (e.g., glass) beads), which are carried into the fracture by a fluid.
• sand and engineered proppants such as resin coated sand and high-strength ceramic materials (e.g., sintered bauxite, crystalline ceramic bubbles, and ceramic (e.g., glass) beads), which are carried into the fracture by a fluid.
• fluid e.g., the fracturing fluid
• fracturing fluid can penetrate into the proppant increasing its density, which can in turn can adversely affect the flow of the proppant into the fractured areas.
• proppants with improved properties.
• the present disclosure provides a method of treating proppant particles present in a fractured subterranean geological formation comprising hydrocarbons, the method comprising injecting fluorinated silane into the fracture to treat the proppant particles in-situ.
• the resulting fluorinated siloxane is bonded to the treated particle.
• the present disclosure provides a method of fracturing a subterranean geological formation comprising hydrocarbons, the method comprising:
• the present disclosure provides a method of fracturing a subterranean geological formation comprising hydrocarbons, the method comprising:
• the method further comprises injecting into a fracture fluid comprising a plurality of proppant particles into the fracture.
• the method further comprises injecting into a fracture fluid comprising a plurality of proppant particles into the fracture.
• the method further comprises injecting into a fracture fluid comprising a plurality of proppant particles into the fracture.
• at least some of the proppant injected into the fracture is treated with the fluorinated silane prior to their injection.
• the fluorinated silane comprises a reactive fluorinated silane selected from the group consisting of:
• a polymeric fluorinated composition comprising:
• a fluorinated urethane oligomer of at least two repeat units comprising:
• Rf is a monovalent or multivalent perfluoroalkyl group optionally interrupted by at least one —O—;
• Rf 2 is a monovalent perfluoroalkyl group optionally interrupted by at least one —O—;
• each R is independently selected from the group consisting of alkyl having one to six carbon atoms and aryl;
• Q is a divalent or trivalent organic linking group
• each Y is independently selected from the group consisting of hydroxyl, alkoxy, acyloxy, and halogen;
• each R 1 is independently selected from the group consisting of hydrogen and alkyl having one to four carbon atoms;
• each W is independently selected from the group consisting of alkylene, arylalkylene, and arylene, wherein alkylene is optionally interrupted or substituted by at least one heteroatom;
• each X is independently selected from the group consisting of —NH—, —O—, and —S—;
• X 1 is selected from the group consisting of —N(R 3 )—, —S—, —O—, —O—C(O)—NH—, and —O-alkylene-O—C(O)—NH—;
• Z is a divalent organic linking group
• x 0, 1, or 2;
• y is 1 or 2;
• z is 1, 2, 3, or 4.
• the fluorinated silane comprises at least one fluorinated urethane oligomer of at least two repeat units comprising:
• R 4 is alkyl having one to four carbon atoms
• Rf 3 is a perfluoroalkyl group having from one to eight carbon atoms
• each Y is independently selected from the group consisting of hydroxyl, alkoxy, acyloxy, and halogen;
• each n is independently an integer from 1 to 4.
• the fracture has a conductivity improved by the presence of the (resulting) fluorinated siloxane.
• the conductivity of a fracture is a measure of the effectiveness of a hydraulically treated fracture or essentially how well the fracture improves the flow of oil or gas from the formation.
• the conductivity of a fracture can be determined using API Conductivity Test RP 61, entitled “Recommended Practices for Evaluating Short Term Proppant Pack Conductivity” (October, 1989).
• Treated proppants and/or fractures described herein 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. While not wanting to be bound by theory, it is believed this enhanced back-production of the fracturing fluids is due to the fluorinated siloxane altering the wettability of the proppant and/or fracture, thus rendering the proppant and/or fracture hydrophobic, oleophobic, and non-wetted by the fracturing fluids.
• An additional advantage of enhancing the fluid production from the fracture comprising the proppant and/or fracture treated with the fluorinated silane is thought to be the reduction in turbulent flow that should significantly reduce non-Darcy effects.
• Non-Darcy effects can effectively reduce the conductivity of a fracture by reducing fluid production.
• Advantages of embodiments of treated particles having a plurality of pores is that the treated particle has at least one of water or oil imbibition up to 95% as compared to a comparable, untreated particle.
• Exemplary proppants for practicing the methods described herein include those known in the art for use in fractured subterranean geological formations comprising hydrocarbons, including engineered proppants (e.g., resin coated sand, sintered bauxite, crystalline ceramic bubbles, and ceramic (e.g., glass) beads), as well as sand graded to desired industry standards).
• engineered proppants e.g., resin coated sand, sintered bauxite, crystalline ceramic bubbles, and ceramic (e.g., glass) beads
• ceramic e.g., glass
• Suitable proppant can be made by techniques known in the art and/or obtained from commercial sources.
• Exemplary proppants include those made of a material selected from the group consisting of sand, thermoplastic, clay, glass, and alumina (e.g., sintered bauxite).
• Examples of proppants include sand, clay-based particles, thermoplastic particles, and sintered bauxite particles.
• Sand proppants are available, for example, from Badger Mining Corp., Berlin, Wis.; Borden Chemical, Columbus, Ohio; Fairmont Minerals, Chardon, Ohio.
• Thermoplastic proppants are available, for example, from the Dow Chemical Company, Midland, Mich.; and BJ Services, Houston, Tex.
• Clay-based proppants are available, for example, from CarboCeramics, Irving, Tex.; and Saint-Gobain, Courbevoie, France.
• Sintered bauxite ceramic proppants are available, for example, from Borovichi Refractories, Borovichi, Russia; 3M Company, St. Paul, Minn.; CarboCeramics, and Saint Gobain.
• Engineered proppants such as glass bead and ceramic microsphere proppants are available, for example, from Diversified Industries, Sidney, British Columbia, Canada; and 3M Company.
• the proppant is at least 100 micrometers (in some embodiments, at least 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2500, or even at least 3000 micrometers; in some embodiments, in a range from 500 micrometers to 1700 micrometers) in size.
• the proppant have particle sizes in a range from 100 micrometers to 3000 micrometers (i.e., about 140 mesh to about 5 mesh) (in some embodiments, in a range from 1000 micrometers to 3000 micrometers, 1000 micrometers to 2000 micrometers, 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 to about 20 mesh), 300 micrometers to 600 micrometers (i.e., about 50 mesh to about 30 mesh), 250 micrometers to 425 micrometers (i.e., about 60 mesh to about 40 mesh), 200 micrometers to 425 micrometers (i.
• the proppants e.g., ceramic particles
• the pores can be closed or open with respect to each other, or a mixture of opened and closed porosity.
• the proppants e.g., ceramic particles
• have a density of at least 2 g/cm 3 in some embodiments, at least 2.5 g/cm 3 , at least 3 g/cm 3 ; in some embodiments, in a range from 2 g/cm 3 to 3 g/cm 3 ).
• the fluorinated silane comprises a reactive fluorinated silane represented by the formula (I):
• Rf is a monovalent perfluoroalkyl group of formula (C n F 2n+1 ), wherein n is an integer from 1 to 20 (in some embodiments, from 3 to 12 or even from 3 to 8). In some embodiments, Rf is C 4 F 9 .
• Rf is a perfluoropolyether group having two or more in-chain oxygen atoms.
• the perfluoropolyether group comprises perfluorinated repeating units selected from the group consisting of —(C n F 2n )—, —(C n F 2n O)—, —(CF(Rf 4 ))—, —(CF(Rf 4 )O)—, —(CF(Rf 4 )C n F 2n O)—, —(C n F 2n CF(Rf 4 )O)—, —(CF 2 CF(Rf 4 )O)—, and combinations thereof (in some embodiments, —(C n F 2n O)—, —(CF(Rf 4 )O)—, —(CF(Rf 4 )C n F 2n O)—, —(C n F 2n CF(Rf 4 )O)—, —(CF 2 CF(Rf 4 )O
• Rf is a monovalent (i.e., z is 1) perfluoropolyether group.
• Rf is terminated with C n F 2n+1 —, C n F 2n+1 O—, or X′C n F 2n O—, wherein X′ is a hydrogen or chlorine atom.
• the terminal group is C n F 2n+1 — or C n F 2n+1 O—, wherein n is an integer from 1 to 6 or from 1 to 3.
• the approximate average structure of Rf is C 3 F 7 O(CF(CF 3 )CF 2 O) p CF(CF 3 )— or CF 3 O(C 2 F 4 O) p CF 2 —, wherein the average value of p is 3 to 50.
• Rf is a divalent (i.e., z is 2) perfluoropolyether group.
• Rf is selected from the group consisting of —CF 2 O(CF 2 O) m (C 2 F 4 O) p CF 2 —, —CF(CF 3 )—(OCF 2 CF(CF 3 )) p O—Rf 5 —O(CF(CF 3 )CF 2 O) p CF(CF 3 )—, —CF 2 O(C 2 F 4 O) p CF 2 —, and —(CF 2 ) 3 O(C 4 F 8 O) p (CF 2 ) 3 —, wherein Rf 5 is a divalent, perfluoroalkylene group containing at least one carbon atom and optionally interrupted in chain by O or N; m is 1 to 50; and p is 3 to 40.
• Rf 5 is (C n F 2n ), wherein n is 2 to 4.
• Rf is selected from the group consisting of —CF 2 O(CF 2 O) m (C 2 F 4 O) p CF 2 —, —CF 2 O(C 2 F 4 O) p CF 2 —, and CF(CF 3 )—(OCF 2 CF(CF 3 )) p O—(C n F 2n )—O(CF(CF 3 )CF 2 O) p CF(CF 3 )—, wherein n is 2 to 4, and the average value of m+p or p or p+p, respectively, is from about 4 to about 24.
• p and m may be non-integral.
• the divalent or trivalent organic linking group, Q can be a linear, branched, or cyclic structure, that may be saturated or unsaturated and optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and/or optionally contains one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, urea, and carbamate.
• Q includes at least 2 carbon atoms and not more than about 25 carbon atoms (in some embodiments, not more than 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or even not more than 10 carbon atoms). When two, three, or four Q groups are present, each Q is independently selected.
• Q is a linear hydrocarbon containing 1 to about 10 carbon atoms, optionally containing 1 to 4 heteroatoms and/or 1 to 4 functional groups. In some of these embodiments, Q contains one functional group.
• Exemplary divalent Q groups include —SO 2 NR 2 (CH 2 ) k O(O)C—, —CON(R 2 )(CH 2 ) k O(O)C—, —(CH 2 ) k O(O)C—, —C(O)N(R 2 )—(CH 2 ) k —, —CH 2 CH(O-alkyl)CH 2 O(O)C—, —(CH 2 ) k C(O)O(CH 2 ) k —, —(CH 2 ) k SC(O)—, —(CH 2 ) k O(CH 2 ) k O(O)C—, —(CH 2 ) k S(CH 2 ) k O(O)C—, —(CH 2 ) k SO 2 (CH 2 ) k O(O)C—, —(CH 2 ) k S(CH 2 ) k OC(O)—, —(CH 2 )
• Exemplary trivalent Q groups include
• R 2 is hydrogen
• Each Y in Formula I is selected from the group consisting of hydroxyl, alkoxy (e.g., of 1 to 4 or even 1 to 2 carbon atoms), aryloxy (e.g., phenoxy), acyloxy (e.g., of 1 to 4 or even 1 to 2 carbon atoms), polyalkyleneoxy, and halogen (e.g., Cl or Br).
• “Polyalkyleneoxy” refers to —O—(CHR 5 —CH 2 O) q —R 3 wherein R 3 is C 1-4 alkyl, R 5 is hydrogen or methyl, with at least 70% of R 5 being hydrogen, and q is 1 to 40, or even 2 to 10.
• each Y is independently a hydrolyzable group selected from the group consisting of alkoxy (e.g., of 1 to 4 or even 1 to 2 carbon atoms), aryloxy (e.g., phenoxy), and halogen (e.g., Cl or Br).
• These hydrolysable groups are capable of hydrolyzing, for example, in the presence of water, optionally under acidic or basic conditions, producing groups capable of undergoing a condensation reaction, for example silanol groups.
• R is alkyl of one to six carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl).
• R is aryl (e.g., phenyl).
• x is 0. In some embodiments, x is 1.
• Some reactive fluorinated silanes of formula I are commercially available, for example, a fluorinated silane (available, for example, from Daikin Industries, Inc., New York, N.Y. under the trade designation “OPTOOL DSX”) and tridecafluorooctyl functional silanes (available, for example, from United Chemical Technologies, Inc., Bristol, Pa. under the trade designation “PETRARCH” (e.g., grades “T2492” and “T2494”).
• a fluorinated silane available, for example, from Daikin Industries, Inc., New York, N.Y. under the trade designation “OPTOOL DSX”
• tridecafluorooctyl functional silanes available, for example, from United Chemical Technologies, Inc., Bristol, Pa. under the trade designation “PETRARCH” (e.g., grades “T2492” and “T2494”).
• Rf is a perfluoropolyether group
• perfluoropolyether esters or functional derivatives thereof can be combined with a functionalized alkoxysilane, such as a 3-aminopropylalkoxysilane, according to the method described in U.S. Pat. No. 3,810,874 (Mitsch et al.).
• a functionalized alkoxysilane such as a 3-aminopropylalkoxysilane
• perfluoropolyether diesters are commercially available (e.g., CH 3 OC(O)CF 2 (OCF 2 CF 2 ) 9-10 (OCF 2 ) 9-10 CF 2 C(O)OCH 3 , a perfluoropolyether diester available, for example, from Solvay Solexis, Houston, Tex., under the trade designation “FOMBLIN ZDEAL”).
• Other perfluoropolyether diesters may be prepared, for example, through direct fluorination of a hydrocarbon polyether diester by methods known in the art (see, e.g., U.S. Pat. Nos. 5,578,278 (Fall et al.) and 5,658,962 (Moore et al.).
• Perfluoropolyether diesters can also be prepared, for example, by oligomerization of hexafluoropropylene oxide (HFPO) and functionalization of the resulting perfluoropolyether carbonyl fluoride according to the methods described in U.S. Pat. No. 4,647,413 (Savu).
• An exemplary fluorinated silane of formula I wherein Rf is a divalent perfluoropolyether group is (CH 3 O) 3 Si(CH 2 ) 3 NHCOCF 2 (OCF 2 CF 2 ) 9-10 (OCF 2 ) 9-10 CF 2 CONH(CH 2 ) 3 Si(OCH 3 ) 3 .
• polyfluoropolyether silanes typically include a distribution of oligomers and/or polymers, and above structures are approximate average structures where the approximate average is over this distribution. These distributions may also contain perfluoropolyethers with no silane groups or more than two silane groups. Typically, distributions containing less than about 10% by weight of compounds without silane groups can be used.
• fluorinated silanes of the formula I, wherein Rf is a monovalent perfluoroalkyl group are known in the art (e.g., by alkylation of fluorinated alcohols or sulfonamides with chloroalkyltrialkoxysilanes, or alkylation with allyl chloride followed by hydrosilation with HSiCl 3 ) (see, e.g., U.S. Pat. No. 5,274,159 (Pellerite et al.).
• each Rf is independently C p F 2p+1 , wherein p is 1 to 8 and R 2 , R, m, n, m′, n′, X, and Q 2 are as defined above, can be prepared, for example, by similar methods (e.g., by alkylation of Rf—S(O) 2 —N(R 2 )—(C n+m H 2(n+m) )—NH(S(O) 2 —Rf or Rf—S(O) 2 —N(R 2 )—(C n H 2n )—CH(OH)—(C m H 2m )—N(R 2 )—S(O) 2 —Rf), respectively, with chloroalkyltrialkoxysilanes) or by reaction of Rf—S(O) 2 —N(R 2 )—(C n H 2n )—CH(OH)—(C m H 2m )—N(R 2 )—S(O) 2
• Perfluoroalkyl silanes of formula I, wherein Rf is a monovalent perfluoroalkyl group include, for example, any one or any combination of the following: C 3 F 7 CH 2 OCH 2 CH 2 CH 2 Si(OCH 3 ) 3 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 Si(OCH 3 ) 3 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 Si(OCH 2 CH 3 ) 3 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 Si(CH 3 )(OCH 3 ) 2 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 SiCl 3 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 Si(CH 3 )Cl 2 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 SiCl(OCH 3 ) 2 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 SiCl(OCH 3 ) 2 ; C 7 F 15 CH 2 OCH 2 CH 2 CH 2 SiCl(
• useful fluorinated siloxanes comprise a condensation product of a polymeric fluorinated composition comprising:
• Rf 2 , R 1 , R, W, X, Y, Z, and x are as defined above.
• the term “polymeric” refers to both oligomers and polymers.
• the number of units represented by formula II is in a range from 1 to 100 (in some embodiments from 1 to 20). In some embodiments, the units represented by formula II are present in a range from 40% by weight to 80% by weight (or even from 50% to 75% by weight) based on the total weight of the polymeric fluorinated composition. In some embodiments, the number of units represented by formula III is in a range from 0 to 100 (or even from 0 to 20). In some embodiments, the units represented by formula III are present in a range from 1% to 20% by weight (or even 2% to 15% by weight) based on the total weight of the polymeric fluorinated composition.
• the polymeric fluorinated composition contains at least 5 mole % (based on total moles of monomers) of Y groups. In some embodiments, the polymeric fluorinated composition has a number average molecular weight in a range from 400 to 100000, from 3500 to 100000, or even from 10000 to 75000 grams per mole or in a range from 600 to 20000, or even from 1000 to 10000 grams per mole. It will be appreciated by one skilled in the art that useful polymeric fluorinated compositions exist as a mixture of compounds.
• a divalent unit of formula II is typically introduced into a polymeric fluorinated composition by polymerizing a monomer of the formula (IIa):
• Fluorochemical monomers of formula IIa and methods for the preparation thereof are known in the art (see, e.g., U.S. Pat. No. 2,803,615 (Ahlbrecht et al.).
• Examples of such compounds include, for example, acrylates or methacrylates derived from fluorochemical telomer alcohols, acrylates or methacrylates derived from fluorochemical carboxylic acids, perfluoroalkyl acrylates or methacrylates as disclosed in U.S. Pat. No. 5,852,148 (Behr et al.), perfluoropolyether acrylates or methacrylates as described in U.S. Pat. No.
• Rf 2 is a monovalent perfluoroalkyl group described above for Rf in embodiments of a compound of formula I.
• the divalent organic linking group, Z can be a linear, branched, or cyclic structure, that may be saturated or unsaturated and optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and/or optionally contains one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, ureylene, and carbamate.
• Z includes at least 1 carbon atom and not more than about 25 carbon atoms (in some embodiments, not more than 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or even not more than 10 carbon atoms).
• Z is a divalent organic linking group as described above for divalent Q groups.
• Z is —C y H 2y —, —CON(R 1 )C y H 2y —, —SO 2 N(R 1 )C y H 2y —, or C y H 2y SO 2 N(R 1 )C y H 2y —, wherein R 1 is hydrogen, or alkyl of one to four carbon atoms, and y is independently an integer from 1 to 6 (in some embodiments from 2 to 4). In some embodiments, R 1 is hydrogen. In some embodiments, R 1 is alkyl of one to four carbon atoms.
• fluorinated monomers of formula IIa include: C 4 F 9 SO 2 N(CH 3 )C 2 H 4 OC(O)CH ⁇ CH 2 ; C 5 F 11 SO 2 N(C 2 H 5 )C 2 H 4 OC(O)CH ⁇ CH 2 ; C 6 F 13 SO 2 N(C 2 H 5 )C 2 H 4 OC(O)C(CH 3 ) ⁇ CH 2 ; C 3 F 7 SO 2 N(C 4 H 9 )C 2 H 4 OC(O)CH ⁇ CH 2 ; C 4 F 9 CH 2 CH 2 OC(O)CH ⁇ CH 2 ; C 5 F 11 CH 2 OC(O)CH ⁇ CH 2 ; C 6 F 13 CH 2 CH 2 OC(O)CH ⁇ CH 2 ; CF 3 (CF 2 ) 2 CH 2 OC(O)CH ⁇ CH 2 , CF 3 (CF 2 ) 2 CH 2 OC(O)C(CH 3 ) ⁇ CH 2 , CF 3 (CF 2 ) 3 CH 2 OC(O)C(CH
• Polymeric fluorinated compositions described herein may have a divalent unit represented by formula III.
• a divalent unit of formula III is typically introduced into a polymeric fluorinated composition by copolymerizing a monomer of formula IIa with a monomer of the formula (IIIa):
• Polymeric fluorinated compositions useful in the fracturing method described herein may optionally include other interpolymerized divalent units, which may contain hydrophobic, hydrophilic, or water-solubilizing groups.
• Useful monomers (including water-solubilizing monomers) that can be combined with those of formulas IIa and IIIa include non-fluorinated monomers described in U.S. Pat. Nos. 6,977,307 (Dams) and 6,689,854 (Fan et. al.).
• Useful polymeric fluorinated compositions may have a chain-terminating group represented by formula IV.
• a chain-terminating group of formula IV may be incorporated into a polymeric fluorinated composition, for example, by polymerizing monomers of formula IIa, optionally IIIa, and optionally at least one non-fluorinated monomer in the presence of a chain-transfer agent of the formula (IVa):
• R, W, Y, and x are as defined above.
• the groups R, Y, and x are those described above for embodiments of a compound of formula I.
• W is alkylene of one to four carbon atoms.
• Some monomers of formula IVa are commercially available (e.g., 3-mercaptopropyltrimethoxysilane (available, for example, from Huls America, Inc., Somerset, N.J., under the trade designation “DYNASYLAN”)); others can be made by conventional synthetic methods.
• a chain-terminating group of formula IV can also be incorporated into a polymeric fluorinated composition by polymerizing monomers of formula IIa, optionally IIIa, and optionally at least one non-fluorinated monomer in the presence of a hydroxyl-functional chain-transfer agent (e.g., 2-mercaptoethanol, 3-mercapto-2-butanol, 3-mercapto-2-propanol, 3-mercapto-1-propanol, 3-mercapto-1,2-propanediol) and subsequent reaction of the hydroxyl functional group with, for example, a chloroalkyltrialkoxysilane.
• a hydroxyl-functional chain-transfer agent e.g., 2-mercaptoethanol, 3-mercapto-2-butanol, 3-mercapto-2-propanol, 3-mercapto-1-propanol, 3-mercapto-1,2-propanediol
• a single chain transfer agent or a mixture of different chain transfer agents may be used to control the number of polymerized monomer units in the polymer and to obtain the desired molecular weight of the polymeric fluorochemical silane.
• the polymeric fluorinated oligomeric composition can conveniently be prepared through a free radical polymerization of a fluorinated monomer with optionally a non-fluorinated monomer (e.g., a water-solubilizing monomer) and at least one of a monomer containing a silyl group or a chain transfer agent containing a silyl group using methods known in the art. See, for example, the methods described in U.S. Pat. Nos. 6,977,307 (Dams) and 6,689,854 (Fan et. al.).
• the fluorinated silane comprises at least one fluorinated urethane oligomer of at least two repeat units (e.g., from 2 to 20 repeating units) comprising at least one end group represented by the formula —O—Z—Rf 2 , and at least one end group represented by the formula —X 1 —W—SiY 3-x (R) x .
• the fluorinated urethane oligomer of at least two repeat units comprises at least one end group represented by the formula —O—(CH 2 ) n N(R 4 )S(O) 2 —Rf 3 , and at least one end group represented by the formula —NH—(CH 2 ) n —SiY 3 , wherein Z, Rf 2 , R 4 , Rf 3 , Y, and x are as defined above, and n is an integer from 1 to 4.
• urethane oligomer refers to oligomers containing at least one of urethane or urea functional groups.
• the at least one fluorinated urethane oligomer of at least two repeat units comprises the reaction product of (a) at least one polyfunctional isocyanate compound; (b) at least one polyol; (c) at least one fluorochemical monoalcohol; (d) at least one silane; and optionally (e) at least one water-solubilizing compound comprising at least one water-solubilizing group and at least one isocyanate-reactive hydrogen containing group.
• at least one polyamine may also be used.
• Useful fluorine urethane oligomers may be prepared, for example, by reaction of at least one polyfunctional isocyanate with at least one polyol and reaction of the resulting oligomer with at least one fluorinated monoalcohol and at least one silane.
• Exemplary reaction conditions, polyfunctional isocyanates, polyols, fluorochemical monoalcohols, silanes, and water-solubilizing compounds are described in U.S. Pat. No. 6,646,088 (Fan et al.).
• Rf 2 is a monovalent perfluoroalkyl group described above for Rf in embodiments of a compound of formula I.
• the divalent organic linking group, Z, in formula —O—Z—Rf 2 can be a linear, branched, or cyclic structure, that may be saturated or unsaturated and optionally contains one or more heteroatoms selected from the group consisting of sulfur, oxygen, and nitrogen, and/or optionally contains one or more functional groups selected from the group consisting of ester, amide, sulfonamide, carbonyl, carbonate, ureylene, and carbamate.
• Z includes at least 1 carbon atom and not more than about 25 carbon atoms (in some embodiments, not more than 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or even not more than 10 carbon atoms).
• Z is a divalent organic linking group as described above for divalent Q groups.
• Z is —C y H 2y —, —CON(R 1 )C y H 2y —, —SO 2 N(R 1 )C y H 2y —, or —C y H 2y SO 2 N(R 1 )C y H 2y —, wherein R 1 is hydrogen or alkyl of one to four carbon atoms, and y is independently an integer from 1 to 6 (in some embodiments from 2 to 4).
• Rf 3 is a perfluoroalkyl group having from 2 to 5 (e.g., 4) carbon atoms.
• An end-group of the formula —O—Z—Rf 2 ((in some embodiments, —O—(CH 2 ) n N(R 4 )S(O) 2 —Rf 3 ) can be incorporated into a fluorinated urethane oligomer by carrying out the condensation polymerization reaction (e.g., as described above) in the presence of a fluorinated monoalcohol of formula HO—Z—Rf 2 .
• Useful fluorinated monoalcohols include, for example, 2-(N-methylperfluorobutanesulfonamido)ethanol; 2-(N-ethylperfluorobutanesulfonamido)ethanol; 2-(N-methylperfluorobutanesulfonamido)propanol; N-methyl-N-(4-hydroxybutyl)perfluorohexanesulfonamide; 1,1,2,2-tetrahydroperfluorooctanol; 1,1-dihydroperfluorooctanol; C 6 F 13 CF(CF 3 )CO 2 C 2 H 4 CH(CH 3 )OH; n-C 6 F 13 CF(CF 3 )CON(H)CH 2 CH 2 OH; C 4 F 9 OC 2 F 4 OCF 2 CH 2 OCH 2 CH 2 OH; C 3 F 7 CON(H)CH 2 CH 2 OH; 1,1,2,2,3,3-hexahydroperfluorode
• An end-group of the formula —X 1 —W—SiY 3-x (R) x can be incorporated into a fluorinated urethane oligomer by carrying out the polymerization reaction (e.g., as described above) in the presence of a silane of formula HX 1 —W—SiY 3-x (R) x (in some embodiments, H 2 N—(CH 2 ) n —SiY 3 ).
• Useful aminosilanes include, for example, H 2 NCH 2 CH 2 CH 2 Si(OC 2 H 5 ) 3 ; H 2 NCH 2 CH 2 CH 2 Si(OCH 3 ) 3 ; H 2 NCH 2 CH 2 CH 2 Si(O—N ⁇ C(CH 3 )(C 2 H 5 )) 3 ; HSCH 2 CH 2 CH 2 Si(OCH 3 ) 3 ; HO(C 2 H 4 O) 3 C 2 H 4 N(CH 3 )(CH 2 ) 3 Si(OC 4 H 9 ) 3 ; H 2 NCH 2 C 6 H 4 CH 2 CH 2 Si(OCH 3 ) 3 ; HSCH 2 CH 2 CH 2 Si(OCOCH 3 ) 3 ; HN(CH 3 )CH 2 CH 2 Si(OCH 3 ) 3 ; HSCH 2 CH 2 CH 2 SiCH 3 (OCH 3 ) 2 ; (H 3 CO) 3 SiCH 2 CH 2 CH 2 NHCH 2 CH 2 CH 2 Si(OCH 3 ) 3 ; HN(CH 3
• the fluorinated silane comprises at least one reactive fluorinated silane, as described above, and a compound of the formula (V):
• M represents an element of valency p+q selected from the group consisting of Si, Ti, Zr, B, Al, Ge, V, Pb, Sn and Zn (in some embodiments selected from the group consisting of Ti, Zr, Si and Al);
• R 6 represents a non-hydrolysable group (e.g., an alkyl group of 1 to 20 carbon atoms which may be straight chained or branched and may include cyclic hydrocarbon structures, a C 6 -C 30 aryl group, optionally substituted by one or more substituents selected from halogens and C 1 -C 4 alkyl groups, or a C 7 -C 30 arylalkyl group);
• p is 3 or 4 depending on the valence of M;
• q is 0, 1 or 2;
• Y 1 represents a hydrolysable group (e.g., alkoxy, acyloxy, and halogen).
• Representative examples of compounds of formula V include tetramethoxysilane, tetraethoxysilane, methyl triethoxysilane, dimethyldiethoxysilane, octadecyltriethoxysilane, methyl trichlorosilane, tetra-methyl orthotitanate, tetra ethyl orthotitanate, tetra-iso-propyl orthotitanate, tetra-n-propyl orthotitanate, tetraethyl zirconate, tetra-iso-propyl zirconate tetra-n-propyl zirconate.
• Mixtures of compounds of formula V may also be used in the preparation of fluorinated silanes.
• the fluorinated silane is dissolved or dispersed in a dispersing medium (e.g., water and/or organic solvent (e.g., alcohols, ketones, esters, alkanes and/or fluorinated solvents (e.g., hydrofluoroethers and/or perfluorinated carbons)) that is then applied to at least one of the fracture or proppant (including in some embodiments, treating the proppant prior to injecting the proppants into the fracture).
• a dispersing medium e.g., water and/or organic solvent (e.g., alcohols, ketones, esters, alkanes and/or fluorinated solvents (e.g., hydrofluoroethers and/or perfluorinated carbons)
• a dispersing medium e.g., water and/or organic solvent (e.g., alcohols, ketones, esters, alkanes and/or fluorinated solvents (e.g., hydrofluoroether
• the concentration of the fluorinated silane in the solution/dispersion solvent is the range from about 5% to about 20% by weight, although amounts outside of this range may also be useful.
• Some formulations containing fluorinated silanes (e.g., of formula I) that may be useful are included in U.S. Pat. No. 6,613,860 (Dams et al.).
• the proppant can be treated, for example, with the fluorinated silane solution/dispersion at temperatures in the range from about 25° C. to about 50° C., although temperatures outside of this range may also be useful.
• the treatment solution/dispersion can be applied to the proppant prior to injection into the fracture using techniques known in the art for applying solutions/dispersions to particles (e.g., mixing the solution/dispersion and proppant in a vessel (in some embodiments under reduced pressure) or spraying the solutions/dispersions onto the proppant).
• the treatment solution/dispersion can be applied using techniques known in the art for injecting solutions/dispersions to fractured subterranean formations (e.g., utilizing a coiled a coiled tubing unit (CTU) or the like).
• CTU coiled tubing unit
• the treatment solution may include contain viscosity enhancing agents (e.g., polymeric viscosifiers), electrolytes, corrosion inhibitors, scale inhibitors, and other such additives that are common to a fracturing fluid.
• viscosity enhancing agents e.g., polymeric viscosifiers
• electrolytes e.g., electrolytes
• corrosion inhibitors e.g., corrosion inhibitors, scale inhibitors, and other such additives that are common to a fracturing fluid.
• the liquid medium can be removed using techniques known in the art (e.g., drying the particles in an oven). After application of the treatment solution/dispersion to the proppant present in the fracture and/or the fracture, the liquid medium can be removed using techniques known in the art (e.g., allowing the fracture to begin production of hydrocarbons).
• the liquid medium can be removed using techniques known in the art (e.g., allowing the fracture to begin production of hydrocarbons).
• about 0.1 to about 5 (in some embodiments, for example, about 0.5 to about 2) percent by weight fluorinated silane is added to the proppant and/or fracture, although amounts outside of this range may also be useful.
• Hydrolysis of the Y groups (i.e., alkoxy, acyloxy, or halogen) of reactive fluorinated silanes typically generates silanol groups, which participate in condensation reactions to form fluorinated siloxanes, for example, according to Scheme I, and/or participate in bonding interactions with silanol groups or other metal hydroxide groups on the surface of the proppant particles).
• the bonding interaction may be through a covalent bond (e.g., through a condensation reaction) or through hydrogen bonding.
• Hydrolysis can occur, for example, in the presence of water optionally in the presence of an acid or base (in some embodiments, acid).
• the water necessary for hydrolysis made be added to a formulation containing the fluorinated silane that is used to coat the particles may be adsorbed to the surface of the particles, or may be present in the atmosphere to which the fluorinated silane is exposed (e.g., an atmosphere having a relative humidity of at least 10%, 20%, 30%, 40%, or even at least 50%).
• Water e.g., brine
• the water present in the subterranean geological formation may be natural occurring water (e.g., connate water) or water from a man-made source (e.g., hydraulic fracturing or waterflooding).
• the condensation of silanol groups is typically carried out at elevated temperature (e.g., in a range from 40° C. to 200° C. or even 50° C. to 100° C.). Under acidic 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.). The rate of the condensation reaction is typically dependent upon temperature and the concentration of fluorinated silane (e.g., in a formulation containing the fluorinated silane).
• fracturing subterranean geological formation comprising hydrocarbons
• a hydraulic fluid is injected into the subterranean geological formation at rates and pressures sufficient to open a fracture therein.
• the fracturing fluid usually water with specialty high viscosity fluid additives
• When injected at the high pressures exceeds the rock strength and opens a fracture in the rock.
• Proppant can be included in the fracturing fluid.
• An advantage, in some embodiments, of treated particles having a plurality of pores is that the treated particle has at least one of water or oil imbibition up to 95% as compared to a comparable, untreated particle.
• the water and oil absorption (i.e., water and oil imbibition) of treated proppant can be measured immersing about 10 grams of the treated proppant in about 20 grams of deionized water or a tetradecane solution (obtained from Sigma-Aldrich, St Louis, Mo.), respectively, for about 1 hour.
• the water or oil, respectively is then filtered off with filter paper (Qualitative Grade 4); Whatman Filter Paper, Florham Park, N.J.
• the surface water or oil, respectively, is then carefully removed with paper towel, and the proppant again weighed.
• the water or oil, respectively, absorption is then calculated based on the difference in weight before and after immersion in the water or oil, respectively.
• the water or oil absorption, respectively, is the average of two measurements.
• a fracture fluid comprising proppant (e.g., bauxite particles) is injected into a well in a subterranean formation that produces hydrocarbons.
• the fracture fluid is injected at a pressure that is above the fracture pressure of the formation, resulting in a fracture and placement of the proppant in the fracture zone.
• the fracturing fluid is subsequently produced once the well is opened for production.
• a methanolic treatment solution containing 99 percent by weight methanol and 1 percent by weight of fluorinated silane is injected into the fracture.
• the treatment solution is injected into the fracture at a pressure sufficient to wet substantially the entire fracture and proppant in the fracture, but not at a pressure high enough to introduce new fractures into the formation.
• the treatment remains in the proppant filled fracture long enough for the silane to treat the fracture and the proppant (e.g., about 1 hour).
• the well is then put back on production, and the treatment fluid is produced, leaving behind the proppant and fluorinated siloxane.

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