SANDSTONE HAVING A MODIFIED WETTABILITY AND A METHOD FOR MODIFYING THE SURFACE ENERGY OF SANDSTONE

Abstract

Methods for modifying the wettability of sandstone. Compositions comprising sandstone having a modified wettability. Such wettability modifications may be useful, for instance, in improving the well-deliverability of an oil and/or gas well located in a sandstone formation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a comparison of n-decane imbibition for Example 1.

FIG. 2 shows a comparison of water imbibition for Example 2.

FIG. 3 shows a comparison of the pressure drop from n-decane injection for Example 3.

FIG. 4 shows a comparison of the pressure drop from water injection for Example 4.

FIG. 5 shows a comparison of relative permeabilities of nitrogen and n-decane for Example 5.

Claims

1. A method for modifying the wettability of sandstone, the method comprising applying a chemical formulation to sandstone, the sandstone bearing at least one of oil or gas, and the chemical formulation comprising: a polar organic solvent,water,a fluorochemical represented by the formula: RfSO2—N(R)(CnH2n)CHZ(CmH2m)N(R′)SO2Rf wherein each Rf is independently —CpF2p+1, where p is an integer from 1 to 8;R is selected from the group consisting of an aryl group and a C1 to C6 alkyl group;m and n are each independently integers from 1 to 20;Z is selected from the group consisting of —H and a group having the formula —(CtH2t)—X-Q—Si(Y′)w(Y)3−w, in which t is an integer from 0 to 4; -X- is selected from the group consisting of —O—, —S— and —NH—; -Q- is selected from the group consisting of —C(O)NH—(CH2)v— and —(CH2)—; v is an integer from 1 to 20; Y is a hydrolyzable group; Y′ is a non-hydrolyzable group; and w is an integer from 0 to 2; andR′ is selected from R and a group represented by the formula —(CH2)v—Si(Y′)w(Y)3−w, with the proviso that when Z is —H, R′ is a group represented by the formula —(CH2)v—Si(Y′)w(Y)3−w; anda hydrolysis catalyst for hydrolyzing the Si—Y bond, the hydrolysis catalyst comprising an acid compound or alkaline compound.

2. The method of claim 1, wherein p is an integer from 2 to 5.

3. The method of claim 1, wherein p is 4, m is an integer from 1 to 6, and n is an integer from 1 to 6.

4. The method of claim 1, wherein p is 4; R is —CH3; m and n are both 1; and Z is selected from the group consisting of —O—(CH2)3Si(OCH2CH3)3, —O—(CH2)3Si(OCH3)3, —OC(O)NH(CH2)3Si(OCH2CH3)3, and —OC(O)NH(CH2)3Si(OCH3)3.

5. The method of claim 1, wherein each Y is independently selected from the group consisting of a halogen, a C1 to C6 alkoxy group, a C1 to C6 acyloxy group, and an aryloxy group.

6. The method of claim 1, wherein Z is —H and R′ is —(CH2)v—Si(Y)3 and wherein each Y is independently selected from the group consisting of —Cl and a C1 to C6 alkoxy group.

7. The method of claim 1, wherein the fluorochemical is selected from the group consisting of [C4F9SO2N(CH3)CH2]2CHOC(O)NH(CH2)3 Si(OCH2CH3)3, [C4F9SO2N(CH3)CH2]2CHOC(O)NH(CH2)3 Si(OCH3)3, [C4F9SO2N(CH3)CH2]2CHO(CH2)3Si(OCH2CH3)3, C4F9SO2N(CH3)CH2CH2CH2N(SO2C4F9)CH2CH2CH2Si(OCH3)3,

8. The method of claim 1, wherein Y′ is selected from the group consisting of a C1 to C6 alkyl group and a C6 to C10 aryl group.

9. The method of claim 8, wherein Y′ is non-fluorinated.

10. The method of claim 8, wherein the alkyl group is unbranched.

11. The method of claim 1, wherein the polar organic solvent is selected from the group consisting of alcohols, ketones, nitriles, formamides, and combinations thereof.

12. The method of claim 1, wherein the polar organic solvent is selected from the group consisting of methanol, ethanol, propanol, butanol, acetone, acetonitrile, dimethylformamide, and combinations thereof.

13. The method of claim 1, wherein the polar organic solvent is selected from the group consisting of methanol, ethanol, propanol, butanol, and combinations thereof.

14. The method of claim 1, wherein Y is selected such that the polar organic solvent is represented by the formula Y—H.

15. The method of claim 1, wherein the acid compound is selected from the group consisting of an organic acid, an inorganic acid, and combinations thereof.

16. The method of claim 15, wherein the acid is an organic acid and wherein the organic acid is soluble in the polar organic solvent.

17. The method of claim 15, wherein the acid is an organic acid and wherein the organic acid is selected from the group consisting of acetic acid, citric acid, formic acid, triflic acid, perfluorobutyric acid, and combinations thereof.

18. The method of claim 15, wherein the acid is an inorganic acid selected from the group consisting of hydroboric acid, sulfuric acid, phosphoric acid, hydrochloric acid, and combinations thereof.

19. The method of claim 1, wherein the acid compound is an acid precursor which forms an acid when contacted with water.

20. The method of claim 1, wherein the alkaline compound is selected from the group consisting of an amine, an alkali metal hydroxide, an alkaline earth metal hydroxide, and combinations thereof.

21. The method of claim 1, wherein applying takes place at least one temperature in a range from 20° C. to 220° C.

22. The method of claim 1, further comprising modifying the wetting of the sandstone.

23. The method of claim 22, wherein the wetting is selected from the group consisting of gas wetting, liquid wetting, and combinations thereof.

24. The method of claim 1, further comprising reducing the rate of n-decane imbibition of the sandstone.

25. The method of claim 1, further comprising reducing the rate of water imbibition of the sandstone.

26. The method of claim 1, further comprising injecting a liquid into the sandstone formation, producing a maximum pressure drop across the sandstone formation, and reducing the maximum pressure drop.

27. The method according to claim 26, wherein the maximum pressure drop is reduced by from 10% to 90%.

28. The method according to claim 1, further comprising extracting from the sandstone formation materials selected from the group consisting of oil, gas, and combinations thereof.

29. The method of claim 1, further comprising covalently bonding the sandstone with a side-chain derived from the fluorochemical, the side-chain represented by the formula [RfSO2—N(R)(CnH2n)]2CHZ′wherein each Rf is independently —CpF2p+1 where p is an integer from 1 to 8;each R is independently selected from the group consisting of an aryl group and a C1 to C6 alkyl group;n is an integer from 1 to 20; andZ′ is a group of the formula —(CtH2t)—X-Q—Si(Y′)w—, in which t is an integer from 0 to 4; -X- is selected from the group consisting of —O—, —S— and —NH—; -Q- is selected from the group consisting of —C(O)NH—(CH2)v— and —(CH2)v—; v is an integer from 1 to 20; Y′ is a non-hydrolyzable group, w is an integer from 0 to 2; and the Si atom shares at least one covalent bond with the sandstone.

30. The method of claim 29, wherein p is an integer from 2 to 5.

31. A composition comprising a sandstone bearing at least one of oil or gas, and a side-chain covalently bonded to the sandstone, the side-chain represented by the formula: [RfSO2—N(R)(CnH2n)]2CHZ′wherein each Rf is independently —CpF2p+1, where p is an integer from 1 to 8;each R is independently selected from the group consisting of an aryl group and a C1 to C6 alkyl group;n is an integer from 1 to 20; andZ′ is a group of the formula —(CtH2t)—X-Q—Si(Y′)w—, in which t is an integer from 0 to 4; -X- is selected from the group consisting of —O—, —S— and —NH—;-Q- is selected from the group consisting of —C(O)NH—(CH2)v— and —(CH2)v—; v is an integer from 1 to 20; Y′ is a non-hydrolyzable group; w is an integer from 0 to 2; and the Si atom shares at least one covalent bond with the sandstone.

32. The composition of claim 31, wherein p is an integer from 2 to 5.