SURFACTANT THAT CHANGES THE WETTABILITY OF TIGHT SANDSTONE AND ITS PREPARATION METHOD AND APPLICATION

• US 20190031945A1
• Filed: 04/18/2018
• Published: 01/31/2019
• Est. Priority Date: 07/28/2017
• Status: Active Grant

• Current Assignee: Petrochina Company Limited (China National Petroleum Corporation)
• Original Assignee: Petrochina Company Limited (China National Petroleum Corporation)
• Inventors: Guo, Gang, Li, Zhongxing, Mu, Lijun, Zhao, Zhenfeng, Zhang, Kuangsheng, Xue, Xiaojia, Wu, Jiang, Li, Kai, Fan, Huabo, Liu, Jin, Zhou, Xiaoqun, Xian, Cheng
• Granted Patent: US 10,544,353 B2
• Time in Patent Office: Days
• CPC Class Codes: C09K 2208/30 Viscoelastic surfactants [VES]
• CPC Class Codes: C09K 8/36 Water-in-oil emulsions
• CPC Class Codes: C09K 8/584 characterised by the use of specific surfactants
• CPC Class Codes: C09K 8/604 Polymeric surfactants
• CPC Class Codes: C09K 8/68 containing organic compounds
• CPC Class Codes: C09K 8/88 macromolecular compounds

Abstract

A surfactant that changes the wettability of tight sandstone and its preparation method and application. By adding the aqueous phase solution into the oil phase solution, and under the action of the emulsifier, a uniformly dispersed phase is achieved. Then adding initiator, stirring and raising the temperature, reacting the reaction at the temperature to obtain a colorless and transparent liquid, i.e., high polymer. At room temperature, adding fluorocarbon surfactant and biosurfactant and stirring was continued for 4 hours to obtain a surfactant that changes the surface wettability of tight sandstone. The surfactant of the present invention can reduce the oil-water interfacial tension, transform the oil-wet surface into water-wet surface, which reduces the adhesion of oil droplets to rock surface and improves the flowability of crude oil in the original stratum, and improves the recovery of low-permeability reservoir.

Claims

1. A method for preparing a surfactant that changes the wettability of tight sandstone, wherein it comprising the following steps:

1) mixing 1 to 3 parts by weight of emulsifier with 30 to 40 parts by weight of solvent oil to prepare an oil phase solvent, adding 5 to 8 parts by weight of modified lignosulphonate monomer into the oil phase solvent to prepare an oil phase mixed solution;

2) adding 15 to 25 parts by weight of hydrophilic cationic monomer and 7 to 10 parts by weight of non-ionic monomer into 50 to 60 parts by weight of water, stirring and dissolving, adjusting the pH value to 8.5 to 9.5 to obtain an aqueous phase solution;

3) adding the aqueous phase solution into the oil phase mixed solution, and then adding 0.10 to 0.15 parts by weight of an initiator therein to cause a polymerization to obtain a high polymer;

wherein the mass ratio of the aqueous phase solution to the oil phase mixed solution is 1;

(2 to 2.5);

4) mixing 32 to 56 parts by weight of fluorocarbon surfactant and 15 to 23 parts by weight of biosurfactant to obtain a surfactant system;

5) adding 40 to 55 parts by weight of the surfactant system into 30 to 43 parts by weight of the high polymer, and stirring the mixture uniformly to obtain the surfactant that changes the wettability of tight sandstone.

2. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the polymerization reaction has a temperature of 60 to 75°

C. and a duration of 12 to 18 hours.

3. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the emulsifier is one or more of fatty acid monoglyceride, lauric acid monoglyceride, propylene glycol fatty acid ester;

the solvent oil is one or more of white oil, naphtha, propanol, isopropanol.

4. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the modified lignosulphonate monomer is sodium hydroxymethyl lignosulphonate, sodium sulfomethylated lignosulphonate, calcium hydroxymethyllated lignosulphonate, 2-acrylamido-2-methylpropanesulfonic acid.

5. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the hydrophilic cationic monomer is one or more of octylphenol polyoxyethylene ether sodium sulfate, nonylphenol polyoxyethylene ether, amido polyoxyethylene ether magnesium disulfate, dodecyl alcohol polyoxyethylene ether sodium disulfate.

6. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the non-ionic monomer is one or more of polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, methyl polyoxyethylene ether.

7. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the initiator is one or more of benzoyl peroxide, benzoyl t-butyl peroxide, azobisisobutyronitrile, azobisisoheptonitrile, dimethyl azobisisobutyrate.

8. The method for preparing a surfactant that changes the wettability of tight sandstone according to claim 1, wherein the fluorocarbon surfactant is one or more of ethyldimethylammonium 3-polyepoxyhexafluoropropaneamidopropyl (2-sulfite), sodium perfluoropropylalkylsulfonate, perfluoroalkyl carboxylic acid amide alkyl carboxylic acid sodium, perfluorooctane sulfonic acid tetraethylamine amide;

the biosurfactant is one or more of sophorolipid, rhamnolipid, trehalose lipid.

9. A surfactant that changes the wettability of tight sandstone prepared by the method according to claim 1, wherein the interfacial tension of the surface wetting surfactant is 10⁻

4 to 10<sup>−

5</sup> mN/m, the contact angle is 55°

.

10. The surfactant according to claim 9, wherein the polymerization reaction has a temperature of 60 to 75°

C. and a duration of 12 to 18 hours.

11. The surfactant according to claim 9, wherein the modified lignosulphonate monomer is sodium hydroxymethyl lignosulphonate, sodium sulfomethylated lignosulphonate, calcium hydroxymethyllated lignosulphonate, 2-acrylamido-2-methylpropanesulfonic acid.

12. The surfactant according to claim 9, wherein the hydrophilic cationic monomer is one or more of octylphenol polyoxyethylene ether sodium sulfate, nonylphenol polyoxyethylene ether, amido polyoxyethylene ether magnesium disulfate, dodecyl alcohol polyoxyethylene ether sodium disulfate.

13. The surfactant according to claim 9, wherein the non-ionic monomer is one or more of polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, methyl polyoxyethylene ether.

14. The surfactant according to claim 9, wherein the fluorocarbon surfactant is one or more of ethyldimethylammonium 3-polyepoxyhexafluoropropaneamidopropyl (2-sulfite), sodium perfluoropropylalkylsulfonate, perfluoroalkyl carboxylic acid amide alkyl carboxylic acid sodium, perfluorooctane sulfonic acid tetraethylamine amide;

the biosurfactant is one or more of sophorolipid, rhamnolipid, trehalose lipid.

15. A use of the surfactant that changes the wettability of tight sandstone prepared by the method according to claim 1 in preparing a fracturing fluid.

16. The use according to claim 15, wherein the polymerization reaction has a temperature of 60 to 75°

C. and a duration of 12 to 18 hours.

17. The use according to claim 15, wherein the modified lignosulphonate monomer is sodium hydroxymethyl lignosulphonate, sodium sulfomethylated lignosulphonate, calcium hydroxymethyllated lignosulphonate, 2-acrylamido-2-methylpropanesulfonic acid.

18. The use according to claim 15, wherein the hydrophilic cationic monomer is one or more of octylphenol polyoxyethylene ether sodium sulfate, nonylphenol polyoxyethylene ether, amido polyoxyethylene ether magnesium disulfate, dodecyl alcohol polyoxyethylene ether sodium disulfate.

19. The use according to claim 15, wherein the non-ionic monomer is one or more of polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, methyl polyoxyethylene ether.

20. The use according to claim 15, wherein the fluorocarbon surfactant is one or more of ethyldimethylammonium 3-polyepoxyhexafluoropropaneamidopropyl (2-sulfite), sodium perfluoropropylalkylsulfonate, perfluoroalkyl carboxylic acid amide alkyl carboxylic acid sodium, perfluorooctane sulfonic acid tetraethylamine amide;

the biosurfactant is one or more of sophorolipid, rhamnolipid, trehalose lipid.