Method for reducing fluid loss during hydraulic fracturing or sand control treatment
View Patent ↗A low viscosity fluid for reducing fluid loss in a relatively low permeability formation has a viscosity of less that 10 CP and contains a low molecular weight viscosifying agent The aqueous medium may be fresh water, salt water, brine or slickwater. The invention has particular applicability when an ultra lightweight (ULW) proppant or sand control particulate is employed. The fluid may be used in reservoirs having a relative permeability less than 10 mD.
1. A method of reducing fluid loss during hydraulic fracturing or a sand control treatment of a subterranean reservoir comprising:
(a) introducing into the reservoir a fluid comprising at least one proppant or sand control particulate and a filtrate having a viscosity less than 50 CP at 170 sec −1 , and
(b) flowing the fluid through the matrix of the reservoir while minimizing the formation of filter cake
wherein,
(i) the filtrate comprises an aqueous medium and a viscosifying agent having a weight average molecular weight less than about 250,000,
(ii) the amount of viscosifying agent in the filtrate is between from about 0.01 to about 10 weight percent, and
(iii) the relative permeability of the reservoir is less than 10 mD.
2. The method of claim 1 , wherein the viscosity of the filtrate is less than about 10 CP at 170 sec −1 .
3. The method of claim 1 , wherein the aqueous medium is slickwater.
4. The method of claim 3 , wherein the weight average molecular weight of the viscosifying agent is less than 40,000.
5. The method of claim 1 , wherein the weight average molecular weight of the viscosifying agent is less than 60,000.
6. The method of claim 1 , wherein the particulate is an ultra lightweight (ULW) particulate having an apparent specific gravity less than or equal to 2.45.
7. The method of claim 6 , wherein the apparent specific gravity of the ULW particulate is less than 1 75.
8. The method of claim 1 , wherein the viscosifying agent is selected from the group consisting of hydroxyethyl cellulose, carboxymethylhydroxylethyl cellulose, hydroxypropyl cellulose, ethylhydroxyethyl cellulose and carboxymethyl cellulose, polyethylene oxide and depolymerized guar.
9. The method of claim 1 , wherein the viscosifying agent is a viscoelastic gel.
10. The method of claim 9 , wherein the viscosifying agent comprises an anionic surfactant and a cationic surfactant.
11. The method of claim 10 , wherein the viscosifying agent comprises sodium xylenesulfonate and N,N,N-trimethyl-1-octadecammonium chloride
12. A method of reducing fluid loss during hydraulic fracturing or a sand control treatment of a reservoir having a relative permeability of less than about 10 mD, comprising
(a) providing a fluid comprising at least one proppant or sand control particulate and a filtrate having a viscosity of less than 50 CP at 170 sec −1 , the filtrate comprising:
(i) slickwater, and
(ii) viscosifying agent, and
(b) introducing the fluid into the reservoir wherein the viscosifying agent is of a size sufficient to flow through the pore throat of the reservoir and into the matrix of the reservoir.
13. The method of claim 12 , wherein the relative permeability of the reservoir is from less than about 1.0 mD to about 10 mD.
14. The method of claim 12 , wherein the weight average molecular weight of the viscosifying agent is less than 60,000.
15. The method of claim 14 , wherein the weight average molecular weight of the viscosifying agent is less than 40,000.
16. The method of claim 12 , wherein the viscosifying agent is a viscoelastic gel.
17. The method of claim 12 , wherein the apparent specific gravity of the proppant or sand control particulate is less than or equal to 1 75.
18. A method of reducing fluid loss during hydraulic fracturing or a sand control treatment of a reservoir having a relative permeability of less than or equal to 10 mD, comprising:
(a) providing a fluid comprising:
(i) slickwater,
(ii) at least one ultra lightweight (ULW) proppant or sand control particulate wherein the apparent specific gravity of the ULW proppant or sand control particulate is less than or equal to 2.45, and
(iii) a viscosifying agent having a weight average molecular weight less than about 250,000,
(b) introducing the fluid into the reservoir, and
(c) flowing the fluid through the matrix of the reservoir.
19. The method of claim 18 , wherein the apparent specific gravity of the ULW proppant or sand control particulate is less than 1 75.
20. The method of claim 18 , wherein the permeability of the reservoir is between from about 0 001 to about 1 0 mD.
21. A method of reducing fluid loss during hydraulic fracturing or a sand control treatment of a formation, comprising
(a) providing a fluid comprising an ultra lightweight proppant or sand control particulate having an apparent specific gravity less than or equal to 2.45 and a filtrate having a viscosity of less than 50 CP at 170 sec −1 , the filtrate comprising slickwater and
viscosifying agent having a weight average molecular weight less than about 250,000, and
(b) introducing the fluid into a reservoir, wherein the relative permeability of the reservoir is less than 1 0 mD, and
(c) flowing the fluid through the matrix of the reservoir while minimizing the formation of filter cake.
22. The method of claim 21 , wherein the weight average molecular weight of the viscosifying agent is less than 40,000.