Patent EA-002585-B1 (EA)
Title: Fluids and techniques for hydrocarbon well completion
Inventor: TIBBLES RAYMOND J
IPC: C09K8/52
Filed: 1999-12-08
Abstract: 1. A well completion fluid for breaking filtercake comprising VES and an enzyme. 2. The completion fluid of claim 1 wherein said enzyme is selected from the group consisting of α-amylase and β-amylase. 3. The completion fluid of claim 1 wherein said VES is N-cis-13-docosenoic-N,N-bis(2-hydroxymethyl)-N-methyl ammonium chloride. 4. The well completion fluid of claim 2 wherein said α-amylase is present in said fluid at a concentration of between about 0.05 and about 1.5 %. 5. The well completion fluid of claim 4 wherein said α-amylase is present in said fluid at a concentration of about 0.5%. 6. The well completion fluid of claim 3 wherein said VES is present in said fluid at a concentration of between about 0.5 and about 7%. 7. The well completion fluid of claim 6 wherein said VES is present in said fluid at a concentration of about 5%. 8. The well completion fluid of claim 7 further comprising a salt selected from the group consisting of 4% KCl and 3% NH4Cl. 9. The well completion fluid of claim 8 wherein said salt is NH4Cl. 10. The well completion fluid of claim 8 further comprising iso-propanol wherein said iso-propanol and said VES are present in said fluid in a ratio of about 1:4. 11. The well completion fluid for breaking filtercake comprising VES an enzyme and a chelating agent, in which said VES is N-cis-13-docosenoic-N,N-bis(2-hydroxymethyl)-N-methyl ammonium chloride and said enzyme is selected from the group consisting of α-amylase and β-amylase. 12. The well completion fluid of claim 11 wherein said chelating agent is selected from the group consisting of HEDP, ATMP, TTPMP, EDTA, CDTA, DTPA, and NTA. 13. The well completion fluid of claim 12 wherein said chelating agent is EDTA. 14. The well completion fluid of claim 13 wherein said EDTA is present in said fluid at a concentration of about 28%. 15. The well completion fluid of claim 14 wherein said α-amylase, said VES, and said EDTA are present in said fluid at concentrations of about 0.5%, 5%, and 28%, respectively. 16.A well completion fluid for breaking filtercake comprising an acid and VES, wherein said VES is N-cis-13-docosenoic-N,N-bis(2-hydroxymethyl)-N-methyl ammonium chloride. 17. The well completion fluid of claim 16 wherein said acid is formic acid. 18. The well completion fluid of claim 16 wherein said formic acid is present in said fluid at a concentration of between about 3 and about 7%. 19. The well completion fluid of claim 16 further comprising a corrosion inhibitor. 20. The well completion fluid of claim 16 further comprising a salt selected from the group consisting of KCl and NH4Cl. 21. The well completion fluid of claim 19 wherein said salt is present in said solution at a concentration of between about 1 and about 5%. 22. The well completion fluid of claim 16 wherein said VES is present in said fluid at a concentration of between about 3 and about 7%. 23. The well completion fluid of claim 20 wherein said VES, said NH4Cl, and said formic acid, are each present in said fluid at concentrations of about 4%. 24. A well completion fluid for breaking filtercake comprising a chelating agent and α-amylase. 25. The well completion fluid of claim 24 further comprising a VES. 26. The well completion fluid of claim 25 wherein said VES is VES is Ncis-13-docosenoic-N,N-bis(2-hydroxymethyl)-N-methyl ammonium chloride. 27. The well completion fluid of claim 25 wherein said chelating agent is selected from the group consisting of HEDP, ATMP, TTPMP, EDTA, CDTA, DTPA, and NTA. 28. The well completion fluid of claim 27 wherein said chelating agent is EDTA. 29. The well completion fluid of claim 28 wherein said EDTA is present in said fluid at a concentration of about 28%. 30. The well completion fluid of claim 2 wherein said EDTA is present in said fluid at a concentration of about 28%. 31. The well completion fluid of claim 24 further comprising α-amylase wherein said α-amylase is present in said fluid at a concentration of between about 0.05 and about 1.0%. 32. The well completion fluid of claim 31 wherein said .alpha.-amylase is present in said fluid at a concentration of about 0.5%. 33. The well completion fluid of claim 32 further comprising a salt selected from the group consisting of KCl and NH4Cl, and wherein said salt is present in said fluid at a concentration of between about 3 and about 5%. 34. A method for breaking filtercake in conjunction with a gravel pack operation comprising circulating through a well, the fluid as in any of claims 1-33. 35. A method for breaking filtercake in conjunction with a gravel pack operation comprising injecting into a well, the fluid as in any of claims 1-33. 36. The method of claim 34 further comprising the step of first injecting into said well, a pre-wash fluid. 37. The method of claim 36 wherein said pre-wash fluid consists essentially of an anionic surfactant solution. 38. A single-stage soak method for breaking filtercake comprising injecting into a wellbore the fluid as in any of claims 1-33, and allowing said fluid to contact said wellbore. 39. A method for breaking filtercake comprising injecting into a wellbore then circulating through said wellbore, the fluid as in any of claims 1-33. 40. The method of claim 38 further comprising the step of first injecting and circulating into said well, a pre-wash fluid. 41. The method of claim 39 further comprising the step of first injecting and circulating into said well, a pre-wash fluid. 42. The method of claim 38 wherein said completion fluid is allowed to contact said wellbore for between about 24 and about 128 hours. 43. A well completion fluid for breaking filtercake comprising VES, α-amylase, and EDTA, present in said fluid in about the following concentrations: 5%, 0.5%, and 28%, respectively. 44. The well completion fluid of claim 43 further comprising NH4Cl, having a concentration in said fluid of about 4%. 45. A well completion fluid for breaking filtercake comprising α-amylase and EDTA, wherein said α-amylase is present in said fluid at a concentration of between about 0.1% and about 1.5%, and wherein said EDTA is present in said fluid at a concentration of between about 5% and about 28%. 46. The well completion fluid of claim 45 further comprising between about 1% and about 10% of a salt. 47. A method for breaking filtercake in conjunction with a gravel pack operation comprising injecting into a well, the fluid as in any of Claims 43-46.