Cystine proteases for bacterial control

Patent metadata

Field	Value
Publication number	US-9458374-B2
Application number	US-201213718877-A
Country	US
Kind code	B2
Filing date	Dec 18, 2012
Priority date	Dec 18, 2012
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A produced water bacterial pretreatment method which includes a) optionally adjusting a pH and a temperature of a produced water containing bacteria; b) adding a cysteine protease to said produced water; c) allowing said cysteine protease to inactivate said bacteria, thus producing pretreated produced water; and d) introducing said pretreated produced water into a wellbore penetrating a subterranean formation is provided.

First claim

I claim:

1. A method of treating an oilfield fluid having an initial viscosity, comprising:
a) adjusting a pH and a temperature of the oilfield fluid containing bacteria;
b) adding a cysteine protease to said oilfield fluid;
c) allowing said cysteine protease to inactivate said bacteria, thus producing pretreated oilfield fluid; and
d) introducing said pretreated oilfield fluid into a wellbore penetrating a subterranean formation.

2. The method of claim 1 , further comprising adding a biological thickening agent to said oilfield fluid.

3. The method of claim 1 , further comprising adding a biological thickening agent to said oilfield fluid before step d).

4. The method of claim 1 , wherein said cysteine protease is selected from the group consisting of caspases, cathepsins, plant cysteine proteases, stable cysteine proteases, Ataxin UIM Domains, otubain-1, otubain-2, ataxin-3, PGPEP-1, ATG4A, TEV Protease, ATG4B/Apg4b, TIN—Ag, BLMG/bleomycin hydrolase, and UCH-L1.

Assignees

• Schlumberger Technology Corp

Inventors

• Sorrells Daniel Denton

Classifications

• C09K8/66 Primary

  Compositions based on water or polar solvents (C09K8/64 takes precedence) · CPC title

• C09K8/04

  Aqueous well-drilling compositions · CPC title

• E21B43/267

  reinforcing fractures by propping · CPC title

• C02F1/50

  by addition or application of a germicide or by oligodynamic treatment {(C02F1/4606, C02F1/467, C02F1/76 take precedence)} · CPC title

• C09K8/84

  Compositions based on water or polar solvents (C09K8/66, C09K8/82 take precedence) · CPC title