Method of fracturing using ultra lightweight proppant suspensions and gaseous streams
View Patent ↗In a method of hydraulically fracturing a hydrocarbon-bearing subterranean formation, a proppant stage is introduced into the fracture which contains a gaseous fluid and an ultra lightweight proppant suspended in a viscosified aqueous fluid. The gaseous fluid of the proppant stage contains at least about 90 volume percent of the combination of gaseous fluid and aqueous fluid. A pad fluid may first be introduced into the formation, the pad fluid containing a gaseous fluid and, optionally, an aqueous fluid. The gaseous fluid of the pad fluid mixture typically contains at least 70 volume percent of the mixture.
1. A method of fracturing a subterranean formation comprising introducing a proppant stage into the subterranean formation, wherein the proppant stage comprises a fine uniform textured foam containing:
(i) a viscosified aqueous fluid having ultra lightweight (ULW) proppant suspended in the viscosified aqueous fluid; and
(ii) a gaseous fluid, wherein the amount of gaseous fluid in the fine uniform textured foam is at least about 85 volume percent;
wherein at least 70% gas volume of bubbles of the fine uniform textured foam have a diameter less than or equal to 0.18 mm and further wherein the proppant stage is introduced into the subterranean formation at a pressure sufficient to create or enlarge a fracture.
2. The method of claim 1 , wherein the diameter of the bubbles of the fine uniform textured foam is between from about 0.01 to about 0.10 mm.
3. The method of claim 1 , wherein the diameter of at least 80% gas volume of the bubbles of the fine uniform textured foam is less than or equal to 0.18 mm.
4. The method of claim 3 , wherein the diameter of the bubbles of the fine uniform textured foam is between from about 0.01 to about 0.10 mm.
5. The method of claim 3 , wherein the diameter of at least 90% gas volume of the bubbles of the fine uniform textured foam is less than or equal to 0.18 mm.
6. The method of claim 5 , wherein the diameter of the bubbles of the fine uniform textured foam is between from about 0.01 to about 0.10 mm.
7. The method of claim 1 , wherein the amount of proppant suspended in the viscosified aqueous fluid is that sufficient to create a partial monolayer of proppant in the fracture.
8. The method of claim 1 , wherein the ULW proppant has an apparent specific gravity less than or equal to 2.25.
9. The method of claim 8 , wherein the apparent specific gravity of the ULW proppant is less than or equal to 1.75.
10. The method of claim 9 , wherein the apparent specific gravity of the ULW proppant is less than or equal to 1.25.
11. The method of claim 1 , wherein the viscosified aqueous fluid contains a viscoelastic surfactant.
12. The method of claim 1 , wherein the gaseous fluid is nitrogen, carbon dioxide or a combination thereof.
13. A method of fracturing a subterranean formation comprising:
(a) pumping into the formation a proppant stage comprising a fine uniform textured foam wherein at least 70% gas volume of bubbles of the fine uniform textured foam have a diameter less than or equal to 0.18 mm, the fine uniform textured foam prepared by:
(i) suspending an ultra lightweight (ULW) proppant in a viscosified aqueous fluid; and then
(ii) combining the viscosified aqueous fluid with a gaseous fluid
wherein the amount of gaseous fluid in the fine uniform textured foam is at least about 85 volume percent; and
(b) creating or enlarging a fracture in the subterranean formation.
14. The method of claim 13 , wherein the viscosified aqueous fluid comprises between from about 6 to about 55 weight percent of ultra lightweight (ULW) proppant having an apparent specific gravity less than or equal to 2.25.
15. The method of claim 13 , further comprising, prior to pumping the proppant stage into the subterranean formation, pumping a pad fluid comprising a gaseous fluid into the formation at a pressure sufficient to initiate a fracture.
16. The method of claim 15 , wherein the pad fluid further contains a proppant.
17. The method of claim 16 , wherein the pad fluid comprises a gaseous fluid and an aqueous fluid.
18. The method of claim 13 , wherein the amount of proppant suspended in the viscosified aqueous fluid is that sufficient to create a partial monolayer of proppant in the fracture.
19. The method of claim 13 , wherein the diameter of at least 90% gas volume of the bubbles of the fine uniform textured foam is less than or equal to 0.18 mm.
20. The method of claim 13 , wherein the diameter of between about 70 to about 90% gas volume of the bubbles is from about 0.01 to about 0.10 mm.
21. The method of claim 13 , wherein the viscosified aqueous fluid is added to the gaseous fluid in step (a) (ii).
22. The method of claim 13 , wherein the gaseous fluid is added to the viscosified aqueous fluid in step (a) (ii).
23. The method of claim 13 , wherein the viscosified aqueous fluid contains a viscoelastic surfactant.
24. A method of fracturing a subterranean formation comprising introducing a proppant stage into a fracture, wherein the proppant stage consists of a fine textured foam comprising a gaseous fluid and an ultra lightweight (ULW) proppant having an apparent specific gravity (ASG) less than or equal to 2.25 suspended in an aqueous system viscosified with a viscoelastic surfactant and wherein the amount of gaseous fluid in the fine textured foam is greater than 90 volume percent and further wherein at least 70% gas volume of bubbles comprising the foam have a diameter that is less than or equal to 0.18 mm.
25. The method of claim 24 , wherein between about 50 to about 90% gas volume of the bubbles have a diameter from about 0.01 to about 0.10 mm.
26. The method of claim 24 , wherein the gaseous fluid comprises at least 95 volume percent of the fluid in the proppant stage.