Method of treating an oil or gas well with biodegradable low toxicity fluid system
AssigneeBJ Services Company
InventorsSandra L. Berry, Kay E. Cawiezel
Life of this patent
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Abstract
A method of treating a well consists of introducing into the wellbore a biodegradable fluid system containing a blend of lactic acid ester, such as ethyl lactate, and a fatty acid ester, such as methyl soyate. The fluid system may be further in the form of a microemulsion that is formed by combining a blend with one or more emulsifiers, an alcohol, and water. The fluid system may be used in displacement, well remediation and stimulation as well as additional, alternative applications such as the cleaning of surface and/or downhole equipment.
Claims35
A method of treating an oil or gas well having a wellbore which comprises introducing into the wellbore a blend comprising a C1–C4 ester of lactic acid, a C1–C4 ester of a C16–C20 fatty acid and an emulsifier, wherein the blend is the discontinuous phase of a microemulsion.
A method of treating a well which comprises introducing into the well a fluid system comprising a 35:65 to 65:35 w/w co-solvent blend of C1–C4 ester of lactic acid:
- C1–C4 ester of a C16–C20 fatty acid.
In a method of well remediation in which a wellbore fluid is introduced into the wellbore for the removal of unwanted deposits therein, the improvement comprising introducing into the wellbore a wellbore fluid comprising a co-solvent blend of a C1–C4 ester of lactic acid and a C1–C4 ester of a C16–C20 fatty acid.
A method of removing drilling muds from a wellbore prior to cementing or prior to introduction of a completion brine, which comprises introducing a fluid system into the wellbore, the fluid system comprising a co-solvent blend of a C1–C4 ester of lactic acid and a C1–C4 ester of a C16–C20 fatty acid.
In a method of treating a well with a well treating gel wherein during such treatment the viscosity of the gel is reduced by the presence of a gel breaker, the improvement using a breaker catalyst comprising a blend of a C1–C4 ester of lactic acid and a C1–C4 ester of a C16–C20 fatty acid to activate the gel breaker.
A method of removing unwanted deposits from a wellbore, well casing, production equipment or recovery equipment which comprises introducing to the wellbore, well casing, production equipment or recovery equipment a blend comprising a C1–C4 ester of lactic acid and a C1–C4 ester of a C16–C20 fatty acid, wherein either (i.) the blend further comprises an emulsifier, the blend being the discontinuous phase of a microemulsion;
- or (ii.) the w/w ratio of C1–C4 ester of lactic acid:C1–C4 ester of a C16–C20 fatty acid in the blend is from 35:65 to 65:35.
Dependencies are inferred from the claim text.