Hydrophobic coating of particulates for enhanced well productivity
Compositions and methods for coated or uncoated particulates, such as proppants, are provided that can, among other things, provide a hydrophobic surface that can enhance well productivity and other compositions and methods are disclosed.
1. A coated particulate, wherein the coating comprises an inner coating adjacent to the particulate comprising a mixture of at least one surfactant and an alkoxylated alcohol and an outer coating comprising an amorphous polyalphaolefin, wherein the amorphous polyalphaolefin is a cross-linked polyalphaolefin polymer.
2. The coated particulate of claim 1 , wherein the outer coating further comprises fumed silica.
3. The coated particulate of claim 2 , wherein the fumed silica is admixed with the amorphous polyalphaolefin.
4. The coated particulate of claim 1 , wherein the inner coating comprises two surfactants.
5. The coated particulate of claim 1 , wherein the at least one surfactant is a sorbitan ester and/or polysorbate.
6. The coated particulate of claim 5 , wherein the sorbitan ester or polysorbate is a polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, or a polyoxyethylene sorbitan monopalmitate, sorbitan monooleate, sorbitan stearate, sorbitan sesquioleate, sorbitan trioleate, sorbitan tristearate, or any combination thereof.
7. The coated particulate of claim 5 , wherein the polysorbate is sorbitan monooleate.
8. The coated particulate of claim 1 , wherein the at the least one surfactant is a hydroxysultaine.
9. The coated particulate of claim 1 , wherein the inner coating comprises a polysorbate or sorbitan ester and a hydroxysultaine.
10. The coated particulate of claim 1 , wherein the alkoxylated alcohol is a fatty alcohol poly-glycol ether.
11. The coated particulate of claim 1 , wherein the particulate is a sand particle, a bauxite particle or a ceramic particle.
12. The coated particulate of claim 1 , wherein the at least one surfactant is selected from the group consisting of: alkyl polyglycosides, alkyl sulfate, alkylbenzene sulfonate, alkyl phosphate, dodecyl dimethyl betaine, dodecyl sulfuric triethanolamine, ethylene glycol distearate, sodium alpha olefin sulfate, sodium fatty acid and methyl ester sulfonate, disodium laureth sulfosuccinate (DLS), cocamidopropyl hydroxyl sulfobetaine, cocamide diethanolamine, cocamide monoethanolamine, cocamidopropyl betaine, cocamidopropylamine oxide, octyl phenol ether, lauryl alcohol ethers, cetyl alcohol ethers, stearyl alcohol ether, alkanolamide, phosphate ester salts, glycerin or its derivative compounds, and any combination thereof.
13. The coated particulate of claim 1 , wherein the at least one surfactant is an alkoxylated sorbitan ester.
14. The coated particulate of claim 13 , wherein the alkoxylated sorbitan ester is selected from the group consisting of: sorbitan laurate esters, sorbitan palmitate ester, sorbitan stearate ester, sorbitan oleate ester, and any combination thereof.
15. The coated particulate of claim 1 , wherein the alkoxylated alcohol is a non-ionic alkoxylated alcohol, a fatty alcohol ethoxylates and/or propoxylates, an alcohol ethoxysulfates, an alkyl ether carboxylate, an alkyl ether phosphate or a combination of a compound of formula:
R a —[O—CH 2 CH 2 ] m —[O—CH 2 CH 2 CH 2 ] n —OR b
wherein R a is C 6 to C 40 hydrocarbon chain,
m is 0 to 25,
n is 0 to 25,
R b is H, SO 3 Na or SO 3 NH 4 , COONa, COOK, Na 3 PO 4 or K 3 PO 4 or C 4 -C 80 hydrocarbon chain.
16. The coated particulate of claim 1 , wherein inner coating further comprises a polymer dispersion admixed with the at least one surfactant.
17. The coated particulate of claim 16 , where the polymer dispersion is a dispersion of an acrylic polymer, an acrylate polymer, a polyacrylate polymer, a polyvinyl acetate polymer, an ethylene-vinyl acetate polymer, a hydroxylated or aminated or epoxylated polymer, a maleic anhydride functionalized polybutadiene polymer, an amide, keto, aldehyde, mercaptan, carboxylic, epoxy, azide, halide terminated polybutadiene polymer, a polyurethane, or an epoxy polymer, or any combinations thereof.
18. A method of extracting oil and/or gas from a subterranean stratum, the method comprising:
injecting into the subterranean stratum a coated particulate of claim 1 ; and
extracting the oil and/or gas from the subterranean stratum.
19. A method of cleaning out a well bore comprising a coated particulate of claim 1 , the method comprising injecting a gas into the well bore to suspend the coated particulates in the well bore and displacing the coated particulate from the well bore.
20. A method of preparing coated particulates of claim 1 , the method comprising:
a) mixing preheated sand with a first layer aqueous solution comprising at least one surfactant, an alkoxylated alcohol, and an acrylic polymer to produce a sand coated with a first layer; and
b) mixing the first layer coated sand with a polyalphaolefin to produce the coated particulate.
21. The coated particulate of claim 1 , wherein the cross-linked polyalphaolefin polymer is a potassium persulfate cross-linked polyalphaolefin polymer, an azobisisobutylnitrile cross-linked polyalphaolefin polymer, or a ferrous sulfate-hydrogen peroxide cross-linked polyalphaolefin polymer.
22. A coated particulate, wherein the coating comprises an inner coating adjacent to the particulate comprising a mixture of at least one surfactant, alkoxylated alcohol, and an acrylic polymer, and an outer coating comprising an amorphous polyalphaolefin.