Composition and process for well cleaning

• US 20030166472A1
• Filed: 02/28/2003
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: Flotek Industries Incorporated
• Original Assignee: CESI Chemical, Inc. (Flotek Industries Incorporated)
• Inventors: Holcomb, David L., Pursley, John T., Penny, Glenn S.
• Granted Patent: US 7,380,606 B2
• Time in Patent Office: Days
• US Class Current: 507/200
• CPC Class Codes: C09K 2208/20 Hydrogen sulfide elimination
• CPC Class Codes: C09K 8/035 Organic additives
• CPC Class Codes: C09K 8/28 containing organic additives
• CPC Class Codes: C09K 8/36 Water-in-oil emulsions
• CPC Class Codes: C09K 8/52 Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning
• CPC Class Codes: C09K 8/602 containing surfactants
• CPC Class Codes: C09K 8/74 combined with additives added for specific purposes
• CPC Class Codes: C09K 8/82 Oil-based compositions C09K8/64 takes precedence
• CPC Class Codes: Y10S 507/927 Well cleaning fluid

Abstract

Disclosed is a microemulsion well treatment microemulsion that is formed by combining a solvent-surfactant blend with a carrier fluid. In preferred embodiments, the solvent-surfactant blend includes a surfactant and a solvent selected from the group consisting of terpenes and alkyl or aryl esters of short chain alcohols. The disclosed well treatment microemulsion can be used in well remediation, stimulation and hydrogen sulfide mitigation operations. Additionally, the well treatment microemulsion can be used in the production of benzothiophenes through interaction with hydrogen sulfide.

Claims

1. A well treatment microemulsion comprising:

a solvent-surfactant blend, wherein the solvent-surfactant blend comprises;

a solvent selected from the group consisting of terpenes and alkyl or aryl esters of short chain alcohols; and

a surfactant;

a carrier fluid; and

wherein the solvent-surfactant blend is combined with the carrier fluid to produce the well treatment microemulsion.

2. The well treatment microemulsion of claim 1, wherein the solvent is d-limonene.

3. The well treatment microemulsion of claim 1, wherein the solvent is ethyl lactate.

4. The well treatment microemulsion of claim 1, wherein the solvent is a combination of d-limonene and ethyl lactate.

5. The well treatment microemulsion of claim 1, wherein the carrier fluid is water-based and the surfactant has a hydrophile-lipophile value of between 8-18.

6. The well treatment microemulsion of claim 1, wherein the carrier fluid is water-based and the surfactant is an oil-in-water surfactant mixture that includes an ethoxylated castor oil.

7. The well treatment microemulsion of claim 6, wherein the oil-in-water surfactant mixture also includes polyoxyethylene sorbitan monopalmitate and polyethylene glycol.

8. The well treatment microemulsion of claim 1, wherein the solvent-surfactant blend comprises:

25%-76% by volume surfactant;

14%-54% by volume d-limonene;

0%-20% by volume isopropanol; and

0%-50% by volume water and triethylene glycol.

9. The well treatment microemulsion of claim 8, wherein the solvent-surfactant blend comprises:

about 27% by volume surfactant, wherein the surfactant is an oil-in-water

surfactant mixture that includes polyoxycthylene sorbitan monopalmitate,

ethoxylated castor oil and polyethylene glycol;

about 34% by volume d-limonene;

about 5% by volume isopropanol;

about 45% by volume water; and

about 5% triethylene glycol.

10. The well treatment microemulsion of claim 1, wherein the carrier fluid is oil-based and the surfactant has a hydrophile-lipophile value of between 3-8.

11. The well treatment microemulsion of claim 1, wherein the carrier fluid is oil-based and the surfactant is a water-in-oil surfactant mixture that includes sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol.

12. The well treatment microemulsion of claim 1, wherein the carrier fluid is oil-based and the solvent-surfactant blend includes:

25%-76% by volume surfactant;

14%-54% by volume d-limonene;

0%-20% by volume isopropanol; and

0%-20% by volume water and triethylene glycol.

13. The well treatment microemulsion of claim 12, wherein the solvent-surfactant blend includes:

about 56% by volume surfactant, wherein the surfactant is a water-in-oil surfactant mixture that includes sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol;

about 34% by volume d-limonene; and

about 10% by volume isopropanol.

14. The well treatment microemulsion of claim 10, wherein the carrier fluid is selected from the group consisting of diesel, kerosene, jet fuel or crude oil.

15. The well treatment microemulsion of claim 1, wherein the well treatment microemulsion includes 10%-99.8% carrier fluid by volume.

16. The well treatment microemulsion of claim 1, wherein the solvent-surfactant blend also includes an alcohol selected from the group of alcohols consisting of detergent range alcohols ethoxylate.

17. The well treatment microemulsion of claim 15, wherein the alcohol is isopropanol, ethylene glycol or triethylene glycol.

18. The well treatment microemulsion of claim 1, wherein the solvent-surfactant blend also includes a salt selected from the group consisting of NaCl, KCl, CaCl₂, and MgCl.

46. The method of claim 38, wherein the carrier fluid is oil-based and includes a cyclic amine and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant is an oil-based surfactant mixture that includes sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol.

19. A method for treating an oil or gas well having a wellbore, comprising:

forming a solvent-surfactant blend;

preparing a microemulsion by combining the solvent-surfactant blend with a carrier fluid; and

injecting the microemulsion into the oil or gas well.

20. The method of claim 19, wherein the step of forming the solvent-surfactant blend comprises:

combining a solvent with a surfactant, wherein the solvent is selected from the group consisting of terpenes and alkyl or aryl esters of short chain alcohols.

21. The method of claim 20, wherein the solvent is d-limonene, ethyl lactate or a mixture of d-limonene and ethyl lactate.

22. The method of claim 19, wherein the carrier fluid is water-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant has a hydrophile-lipophile balance value of between 8-18.

23. The method of claim 20, wherein the surfactant is a oil-in-water surfactant mixture that includes an ethoxylated castor oil.

24. The method of claim 23, wherein the oil-in-water surfactant mixture also includes polyoxyethylene sorbitan monopalmitate and polyethylene glycol.

25. The method of claim 19, wherein the carrier fluid is oil-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant has a hydrophile-lipophile balance value of between 3-8.

26. The method of claim 19, wherein the carrier fluid is oil-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant is a water-in-oil mixture of ethoxylated castor oil, sorbitan monopalmitate and polyethylene glycol.

27. The method of claim 19, wherein the method further comprises:

combining the microemulsion with proppant material; and

injecting the microemulsion and proppant material into the wellbore to stimulate the oil or gas well.

28. The method of claim 27, wherein the solvent-surfactant blend comprises:

about 25%-76% by volume of an oil-in-water surfactant mixture that includes polyoxyethylene sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol;

about 14%-54% by volume d-limonene;

about 0%-20% by volume isopropanol; and

about 0%-50% by volume of water.

29. The method of claim 19, wherein the carrier fluid is a drilling fluid and the method further comprises:

combining the microemulsion with the drilling fluid;

injecting the microemulsion and drilling fluid into the oil or gas well during a drilling operation.

30. The method of claim 29, wherein the drilling fluid is oil-based and the microemulsion comprises:

about 25%-76% by volume of a water-in-oil surfactant mixture that includes sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol;

about 14%-54% by volume d-limonene;

about 0%-20% by volume isopropanol; and

about 0%-5% by volume of water.

31. The method of claim 29, wherein the drilling fluid is water-based and the microemulsion comprises:

about 25%-76% by volume of an oil-in-water surfactant mixture that includes polyoxyethylene sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol;

about 14%-54% by volume d-limonene;

about 0%-20% by volume isopropanol; and

about 0%-50% by volume of water.

32. The method of claim 19, wherein the step of preparing a microemulsion further comprises:

combining the solvent-surfactant blend with an acidified carrier fluid to prepare a microemulsion suitable for acidizing operations.

33. The method of claim 32, wherein the acidified carrier fluid includes one or more acids selected from the group of hydrochloric, acetic, formic, and hydrochloric-hydroflouric acids.

34. The method of claim 32, wherein the

acidified carrier fluid includes about 3%-28% acid by volume of the micro emulsion.

35. The method of claim 34, wherein the acidified carrier fluid includes about 15% hydrochloric acid by volume of the microemulsion.

36. The method of claim 34, wherein the step of combining the solvent-surfactant blend with an acidified carrier fluid further comprises:

adding 0.2%-5% solvent-surfactant by volume of the microemulsion to the acidified carrier fluid.

37. The method of claim 32, wherein the solvent-surfactant blend comprises:

about 25%-76% by volume surfactant;

about 14%-54% by volume d-limonene;

about 0%-20% by volume isopropanol; and

about 0%-50% by volume of water.

38. A method for the treatment of hydrogen sulfide;

comprising;

forming a solvent-surfactant blend;

preparing a microemulsion by combining the solvent-surfactant blend with a carrier fluid; and

contacting the hydrogen sulfide with the microemulsion.

39. The method of claim 38, wherein the step of contacting the hydrogen sulfide with the microemulsion comprises:

injecting the microemulsion into a wellbore.

40. The method of claim 38, wherein the step of contacting the hydrogen sulfide with the microemulsion comprises:

placing the microemulsion in a container in fluid communication with a source of hydrogen sulfide.

41. The method of claim 38, wherein the step of forming the solvent-surfactant blend comprises:

combining a solvent with a surfactant, wherein the solvent is selected from the group consisting of terpenes.

42. The method of claim 41, wherein the step of forming the solvent-surfactant blend comprises:

combining a solvent with a surfactant, wherein the solvent is d-limonene.

43. The method of claim 38, wherein the carrier fluid is water-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant has a hydrophile-lipophile balance value of between 8-18.

44. The method of claim 38, wherein the carrier fluid is water-based and includes a cyclic amine and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant is an oil-in-water surfactant mix that includes polyoxyethylene sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol.

45. The method of claim 38, wherein the carrier fluid is oil-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant has a hydrophile-lipophile balance value of between 3-8.

47. A method for the production of benzothiophenes, comprising:

forming a solvent-surfactant blend;

preparing a microemulsion by combining the solvent-surfactant blend with a carrier fluid; and

contacting the hydrogen sulfide with the microemulsion to produce benzothiophenes.

48. The method of claim 47, wherein the step of contacting the hydrogen sulfide with the microemulsion comprises:

injecting the microemulsion into a wellbore.

49. The method of claim 47, wherein the step of contacting the hydrogen sulfide with the microemulsion comprises:

placing the microemulsion in a container in fluid communication with a source of hydrogen sulfide.

50. The method of claim 47, wherein the step of forming the solvent-surfactant blend comprises:

combining a solvent with a surfactant, wherein the solvent is selected from the group consisting of terpenes and cyclic amines.

51. The method of claim 50, wherein the step of forming the solvent-surfactant blend comprises:

combining a solvent with a surfactant, wherein the solvent is d-limonene, cyclic amines or a mixture of d-limonene and cyclic amines.

52. The method of claim 47, wherein the carrier fluid is water-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant has a hydrophile-lipophile balance value of between 8-18.

53. The method of claim 47, wherein the carrier fluid is water-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant is an oil-in-water surfactant mix that includes polyoxyethylene sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol.

54. The method of claim 47, wherein the carrier fluid is oil-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant has a hydrophile-lipophile balance value of between 3-8.

55. The method of claim 47, wherein the carrier fluid is oil-based and the step of forming the solvent-surfactant blend comprises:

combining a solvent and a surfactant, wherein the surfactant is a water-in-oil surfactant mix that includes sorbitan monopalmitate, ethoxylated castor oil and polyethylene glycol.

56. A method of treating an oil or gas well with a well treatment microemulsion, wherein the oil or gas well has a wellbore that contains water-based fluid, the method comprising:

forming a solvent-surfactant blend by combining a solvent with an oil-in-water based surfactant mixture that includes a surfactant having a hydrophile-lipophile value of about 8 to 18; and

injecting the solvent-surfactant blend into the wellbore, wherein the solvent-surfactant blend mixes with the water-based fluid to form a well treatment microemulsion.