Claims for Patent: 9,090,815

Summary for Patent: 9,090,815

Title:	Method of using asparaginase as a polyacrylamide enzyme breaker
Abstract:	Asparaginase, such as asparaginase derived from Aspergillus oryzae, may be used to break down or defragment polyacrylamides in oil field applications. The asparaginase is useful in reducing the viscosity of a fracturing fluid containing polyacrylamide and a crosslinking agent. The asparaginase is also useful in breaking down or defragmenting a polyacrylamide friction reducing agent, such as in a slickwater fracturing operation. Asparaginase may also be used to break down or defragment filter cakes containing polyacrylamide.
Inventor(s):	Gupta; D. V. Satyanarayana (The Woodlands, TX)
Assignee:	Baker Hughes Incorporated (Houston, TX)
Application Number:	13/467,906
Patent Claims:	1. A method of treating a well or a subterranean formation penetrated by a well wherein the well has been treated with a fluid containing a polyacrylamide, the method comprising introducing into the well or subterranean formation a fluid comprising an aqueous solution of an asparaginase breaker wherein the amount of asparaginase breaker in the fluid is between from about 0.1 lb/1,000 gals to about 10 lb/100 gals and degrading the polyacrylamide with the asparaginase. 2. The method of claim 1, wherein the asparaginase is used to remove a filter cake by breaking down polyacrylamide in the filter cake. 3. The method of claim 2, wherein the asparaginase is used to remove a filter cake formed from a drilling fluid or a drill-in fluid being introduced into the well. 4. The method of claim 1, wherein the asparaginase is derived from Aspergillus oryzae. 5. The method of claim 1, wherein the polyacrylamide is a homopolymer or copolymer derived from a monomer of formula: R.sup.1CONR.sup.2R.sup.3 (I) wherein R.sup.1 is a linear or branched alkyl or alkenyl group, and R.sup.2 and R.sup.3 are independently selected from hydrogen or a linear or branched alkyl or alkenyl group. 6. The method of claim 5, the polyacrylamide is a homopolymer or copolymer derived from acrylamide; N-substituted hydrosoluble derivatives of acrylamide; and hydrosoluble N-vinylamides. 7. The method of claim 5, wherein the polyacrylamide is a copolymer further derived from a monomer selected from the group consisting of acrylic acid, salts of acrylic acid, methacrylic acid, salts of methacrylic acid, maleic anhydride, acrylamido-methylpropyl sulfonic acid, salts of acrylamido-methylpropyl sulfonic acid, styrenesulfonic acid, salts of styrenesulfonic acid, vinylsulfonic acid, salts of vinylsulfonic acid, quaternised and non-quaternised vinylpyridine and vinyl phosphonate, and acrylamido-methylpropyl sulfonic acid. 8. The method of claim 1, wherein the asparaginase is introduced into the well or subterranean formation during a hydraulic fracturing operation. 9. The method of claim 1, wherein the asparaginase is introduced into a well or subterranean formation during a slickwater fracturing operation. 10. The method of claim 1, wherein the polyacrylamide is a viscosifying agent and further wherein the fluid contains a crosslinking agent. 11. The method of claim 1, wherein the asparaginase is used to remove a filter cake formed by a fluid loss pill. 12. The method of claim 1, wherein the asparaginase is added to the well or subterranean formation in the fluid containing the polyacrylamide. 13. The method of claim 1, wherein the asparaginase is added to the well or subterranean formation before or after the addition of the fluid containing the polyacrylamide. 14. The method of claim 1, wherein the pH of the fluid is between about 4.5 to about 5.25. 15. A method of treating a subterranean formation which comprises: (a) introducing into the wellbore a fluid containing a polyacrylamide and a crosslinking agent and further introducing into the wellbore an asparaginase in an aqueous solution; and (b) breaking the viscosity of the fluid by defragmenting the polyacrylamide with the asparaginase. 16. The method of claim 15, wherein the asparaginase is added to the wellbore in the same fluid containing the polyacrylamide wherein the amount of asparaginase in the fluid is between from about 0.1 lb/1,000 gals to about 10 lb/100 gals. 17. The method of claim 15, wherein the asparaginase is added to the wellbore before or after the addition of the fluid containing the polyacrylamide. 18. The method of claim 15, wherein the asparaginase is derived from Aspergillus oryzae. 19. In a method of treating a well or a subterranean formation penetrated by a well with a fluid containing a polyacrylamide and then degrading the polyacrylamide with a breaker, the improvement comprising introducing into the well or subterranean formation an aqueous solution of a breaker comprising Aspergillus oryzae. 20. A method of removing a polyacrylamide containing filter cake in a well wherein the filter cake is formed during drilling or completion of the well, the method comprising pumping into the well a fluid comprising asparaginase and defragmenting the polyacrylamide with the asparaginase. 21. A method of slickwater fracturing a subterranean formation having a permeability less than 1 millidarcy comprising: (a) introducing into the wellbore penetrating the subterranean formation an aqueous solution of an asparaginase and an aqueous well treatment fluid void of a viscosifying polymer, wherein the well treatment fluid comprises a polyacrylamide friction reducing agent; and (b) reducing the viscosity of the well treatment fluid by defragmenting the polyacrylamide friction reducing agent with the asparaginase. 22. The method of claim 21, wherein the asparaginase is added to the wellbore in the same fluid containing the polyacrylamide. 23. The method of claim 21, wherein the asparaginase is added to the wellbore before or after the addition of the fluid containing the polyacrylamide. 24. The method of claim 21, wherein the asparaginase is derived from Aspergillus oryzae.

Details for Patent 9,090,815

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Recordati Rare Diseases, Inc.	ELSPAR	asparaginase	For Injection	101063	01/10/1978		2031-05-13