Methods for enhancing propped fracture conductivity
Various embodiments disclosed relate to methods of treating a subterranean formations that provide enhanced fracture conductivity over other methods. In various embodiments, the present invention provides a method of treating a subterranean formation. The method can include obtaining or providing a composition including a tackifier. The composition can have a viscosity less than about 20 cP. The method can include placing the composition in a subterranean formation downhole. The method can also include fracturing the subterranean formation with the composition.
1. A method of treating a subterranean formation, the method comprising:
providing a pad fluid comprising a tackifier and a first proppant, wherein the first proppant comprises a particle size of 150 mesh or smaller, and wherein the tackifier is at least partially coated on the first proppant, the pad fluid having a viscosity of less than about 20 cP at standard temperature and pressure;
fracturing the subterranean formation with the pad fluid and at least partially coating one or more fracture face with the tackifier;
providing a second fluid comprising a second proppant, wherein the second proppant comprises a particle size larger than the first proppant; and
placing the second fluid in fractures and fracture branches created in the subterranean formation by the pad fluid at a pressure greater than the fracture gradient of the subterranean formation.
2. The method of claim 1 , wherein the viscosity of the pad fluid is about 0.001 cP to about 20 cP.
3. The method of claim 1 , wherein the tackifier contacts a face of at least one fracture generated by the fracturing.
4. The method of claim 1 , wherein the first proppant in the pad fluid comprises at least one proppant selected from the group consisting of sand, gravel, glass beads, polymer beads, ground products from shells and seeds such as walnut hulls, and manmade materials such as ceramic proppant, bauxite, tetrafluoroethylene materials, fruit pit materials, processed wood, composite particulates prepared from a binder and fine grade particulates such as silica, alumina, fumed silica, carbon black, graphite, mica, titanium dioxide, meta-silicate, calcium silicate, kaolin, talc, zirconia, boron, fly ash, hollow glass microspheres, solid glass, and combinations thereof.
5. The method of claim 1 , wherein about 0.001 wt % to about 30 wt % of the pad fluid is the tackifier.
6. The method of claim 1 , wherein the tackifier further comprises at least one of a shellac, a silyl-modified polyamide, a polyester, a polycarbonate, a polycarbamate, a urethane, a natural resin, an epoxy-based resin, a furan-based resin, a phenolic-based resin, a urea-aldehyde resin, a phenol/phenol formaldehyde/furfuryl alcohol resin, an acrylic acid polymer, an acrylic acid ester polymer, an acrylic acid homopolymer, an acrylic acid ester homopolymer, poly(methyl acrylate), poly(butyl acrylate), poly(2-ethylhexyl acrylate), an acrylic acid ester copolymer, a methacrylic acid derivative polymer, a methacrylic acid homopolymer, a methacrylic acid ester homopolymer, poly(methyl methacrylate), poly(butyl methacrylate), poly(2-ethylhexyl methacrylate), an acrylamidomethylpropane sulfonate polymer or copolymer or derivative thereof, and an acrylic acid/acrylamidomethylpropane sulfonate copolymer.
7. The method of claim 1 , wherein the tackifier further comprises at least one of a polyamine, a polyimine, poly(2-(N,N-dimethylamino)ethyl methacrylate), poly(2-(N,N-diethylamino)ethyl methacrylate), a poly(vinyl imidazole), and a copolymer comprising at least one of the foregoing and at least one of polyethylene, polypropylene, polyethylene oxide, polypropylene oxide, polyvinylpyridine, polyacrylic acid, polyacrylate, and polymethacrylate.
8. The method of claim 1 , wherein the pad fluid further comprises a hardening agent.
9. The method of claim 1 , wherein the pad fluid further comprises a surfactant.
10. The method of claim 1 , wherein the pad fluid further comprises a clay stabilizer.
11. The method of claim 10 , wherein the clay stabilizer is a zirconium salt, an ammonium salt, alumina, a polycationic polymer, choline chloride, tetramethyl ammonium chloride, potassium chloride, potassium bromide, potassium acetate, potassium hydroxide, sodium chloride, sodium bromide, sodium acetate, sodium hydroxide, ammonium chloride, ammonium bromide, ammonium acetate, ammonium hydroxide, calcium chloride, calcium bromide, calcium acetate, calcium hydroxide, zinc chloride, zinc bromide, zinc acetate, zinc hydroxide.
12. The method of claim 10 wherein the clay stabilizer is a 1,3-substituted 2-hydroxypropane, wherein the 1- and 3-positions are independently substituted by a moiety selected from the group consisting of pyridinium, alkyl pyridinium, and R 3 N + -, wherein each R is independently selected from the group consisting of benzyl, (C 1 -C 12 ) alkyl, and (C 1 -C 12 ) alkyl substituted by one hydroxyl group.
13. The method of claim 10 , wherein the clay stabilizer is 1,3-bis(trimethylammonium chloride)-2-hydroxypropane.
14. The method of claim 1 , wherein the pad fluid further comprises a crosslinked gel or a crosslinkable gel.
15. The method of claim 1 , further comprising forming at least one adhered layer of the first proppant on the at least on fracture face.
16. The method of claim 1 , further comprising injecting a second pad fluid into the fractures created by the pad fluid, wherein the second pad fluid comprises the tackifier, wherein the injecting the second pad fluids follows the pad fluid and is before the placing the second fluid.
17. The method of claim 1 , wherein the second proppant has a particle size of 150 mesh to 1000 mesh.
18. The method of claim 1 , wherein the first proppant is present in the pad fluid in an amount of about 2 wt % or more, and wherein the second proppant is present in the second fluid in an amount of about 2 wt % or more, and wherein the pad fluid and the second fluid are both aqueous and individually comprise water in an amount of about 50 wt % to about 99 wt %.
19. The method of claim 1 , wherein the tackifier comprises a polyamide condensation product of a fatty acid and a polyamine.
20. A method of treating a subterranean formation, the method comprising:
placing in the subterranean formation a pad fluid comprising a tackifier, a first proppant and an organic clay stabilizer, the tackifier comprising a polyamide condensation product of a fatty acid and a polyamine, wherein the organic clay stabilizer is a 1,3-substituted 2-hydroxypropane, wherein the 1- and 3-positions are independently substituted by a moiety selected from the group consisting of pyridinium, alkyl pyridinium, and R 3 N + -, wherein each R is independently selected from the group consisting of benzyl, (C 1 -C 12 ) alkyl, and (C 1 -C 12 ) alkyl substituted by one hydroxy group, the composition having a viscosity of less than about 20 cP at standard temperature and pressure, wherein the first proppant comprises a particle size of 150 mesh or smaller;
fracturing the subterranean formation with the pad fluid, to form at least one fracture; and
substantially coating at least part of a face of the fracture with the pad fluid;
placing a second fluid in fractures and fracture branches created in the subterranean formation by the pad fluid at a pressure greater than the fracture gradient of the subterranean formation, wherein the second fluid comprises a second proppant having a larger particle size than the first proppant; and
forming at least one adhered at least partial layer of the second proppant on the face, wherein the tackifier enhance adhesion of the second proppant to the face;
wherein the fractured subterranean formation has a higher permeability than a corresponding subterranean formation subjected to a corresponding method that is free of the tackifier and the organic clay stabilizer.