Chemically-induced pulsed fracturing method

Patent metadata

Field	Value
Publication number	US-9488042-B2
Application number	US-201514689874-A
Country	US
Kind code	B2
Filing date	Apr 17, 2015
Priority date	Apr 17, 2014
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

A method of increasing a stimulated reservoir volume in a wellbore in a gas-containing formation includes the steps of mixing an exothermic reaction component to achieve a pre-selected solution pH, the exothermic reaction component is operable to react at a wellbore temperature to generate a pressure pulse, mixing the exothermic reaction component with a viscous fluid component operable to fracture the gas-containing formation to create fractures, and a proppant component, the proppant component carried to the fractures by the viscous fluid, the proppant component comprises a proppant operable to hold open the fractures, to form a fracturing fluid, injecting the fracturing fluid into the wellbore in the gas-containing formation to create fractures, and generating the pressure pulse when the exothermic reaction component reaches the wellbore temperature, the pressure pulse operable to create auxiliary fractures, wherein the auxiliary fractures create a fracture network, the fracture network increases the stimulated reservoir volume.

First claim

What is claimed is:

1. A method of increasing a stimulated reservoir volume in a wellbore in a gas-containing formation, the method comprising the steps of:
mixing an exothermic reaction component in an aqueous solution to achieve a pre-selected solution pH, wherein the exothermic reaction component is operable to react at a pre-selected wellbore temperature to generate a pressure pulse;
mixing the aqueous solution with a viscous fluid component to form a fracturing fluid, the viscous fluid component operable to fracture the gas-containing formation to create fractures, and the fracturing fluid further comprising a proppant component, the proppant component carried to the fractures by the viscous fluid component, the proppant component comprises a proppant, the proppant operable to hold open the fractures;
injecting the fracturing fluid into the wellbore in the gas-containing formation to create fractures; and
after injecting the fracturing fluid into the wellbore, generating the pressure pulse with an unreacted amount of exothermic reaction component in situ, the unreacted amount of exothermic reaction component in situ sufficient for the pressure pulse to be between about 500 psi and about 50,000 psi, when the exothermic reaction component reaches the pre-selected wellbore temperature, such that the pressure pulse is operable to create auxiliary fractures by released pressure without the viscous fluid component and the proppant component, wherein the auxiliary fractures create a fracture network, wherein the fracture network increases the stimulated reservoir volume.

2. The method of claim 1 , wherein the exothermic reaction component comprises an ammonium containing compound and a nitrite containing compound.

3. The method of claim 2 , wherein the ammonium containing compound comprises NH 4 Cl and the nitrite containing compound comprises NaNO 2 .

4. The method of claim 1 , wherein the pre-selected solution pH is between 5.7 and 9.

5. The method of claim 1 , wherein the wellbore temperature is in a range between 48.8° C. (120° F.) and 121.1° C. (250° F.).

6. The method of claim 1 , wherein the pressure pulse creates the auxiliary fractures in less than 10 seconds.

7. The method of claim 1 , wherein the pressure pulse creates the auxiliary fractures in less than 5 seconds.

8. A method of increasing a stimulated reservoir volume in a wellbore in a gas-containing formation that has fractures, the method comprising the steps of:
mixing an exothermic reaction component in an aqueous solution to achieve a pre-selected solution pH, wherein the exothermic reaction component is operable to react at a pre-selected wellbore temperature to generate a pressure pulse in the absence of a viscous fluid component and proppant component;
injecting the solution into the gas-containing formation; and
generating the pressure pulse when the exothermic reaction component reaches the pre-selected wellbore temperature, such that the pressure pulse is operable to create auxiliary fractures, wherein the auxiliary fractures create a fracture network, wherein the fracture network increases the stimulated reservoir volume.

9. The method of claim 1 , wherein the method generates substantially no foam.

10. The method of claim 8 , wherein the exothermic reaction component comprises an ammonium containing compound and a nitrite containing compound.

11. The method of claim 10 , wherein the ammonium containing compound comprises NH 4 Cl and the nitrite containing compound comprises NaNO 2 .

12. The method of claim 8 , wherein the pre-selected solution pH is between 5.7 and 9.

13. The method of claim 8 , wherein the wellbore temperature is in a range between 48.8° C. (120° F.) and 121.1° C. (250° F.).

14. The method of claim 8 , wherein the pressure pulse is between 500 psi and 50,000 psi.

15. The method of claim 8 , wherein the pressure pulse creates the auxiliary fractures in less than 10 seconds.

16. The method of claim 8 , wherein the pressure pulse creates the auxiliary fractures in less than 5 seconds.

17. The method of claim 8 , wherein the method generates substantially no foam.

18. A method for hydraulic fracturing of a hydrocarbon-bearing formation, the method comprising the steps of:
determining a wellbore temperature at a depth within the hydrocarbon-bearing formation;
determining a length of time for which a hydraulic fracturing fluid needs to reach the depth within the hydrocarbon-bearing formation and reach the wellbore temperature at the depth;
mixing an exothermic reaction component in an aqueous solution to achieve a pre-selected solution pH, wherein the exothermic reaction component is operable to react at the wellbore temperature at the depth within the hydrocarbon-bearing formation to generate a pressure pulse;
mixing the aqueous solution with a viscous fluid component to form the hydraulic fracturing fluid, the viscous fluid component operable to fracture the hydrocarbon-bearing formation to create fractures, and the fracturing fluid further comprising a proppant component, the proppant component carried to the fractures by the viscous fluid component, the proppant component comprises a proppant, the proppant operable to hold open the fractures;
injecting the fracturing fluid into the wellbore in the hydrocarbon-bearing formation to create fractures; and
generating the pressure pulse when the exothermic reaction component reaches the wellbore temperature, such that the pressure pulse is operable to create auxiliary fractures, wherein the auxiliary fractures create a fracture network, wherein the fracture network increases the stimulated reservoir volume, and the exothermic reaction component compatible with the viscous fluid component and operable to reduce a viscosity of the viscous fluid component.

19. The method of claim 18 , wherein the exothermic reaction component comprises an ammonium containing compound and a nitrite containing compound.

20. The method of claim 19 , wherein the ammonium containing compound comprises NH 4 Cl and the nitrite containing compound comprises NaNO 2 .

21. The method of claim 18 , wherein the pre-selected solution pH is between 5.7 and 9.

22. The method of claim 18 , wherein the wellbore temperature is in a range between 48.8° C. (120° F.) and 121.1° C. (250° F.).

23. The method of claim 18 , wherein the pressure pulse is between 500 psi and 50,000 psi.

24. The method of claim 18 , wherein the pressure pulse creates the auxiliary fractures in less than 10 seconds.

25. The method of claim 18 , wherein the pressure pulse creates the auxiliary fractures in less than 5 seconds.

26. The method of claim 18 , wherein the method generates substantially no foam.

Assignees

• Saudi Arabian Oil Co

Inventors

• Al-Nakhli Ayman R
• Abass Hazim H
• Hilab Victor V
• Khan Mirajuddin R
• Al-Otaibi Ahmad S

Classifications

• C09K8/52 Primary

  Compositions for preventing, limiting or eliminating depositions, e.g. for cleaning · CPC title

• E21B43/267

  reinforcing fractures by propping · CPC title

• C09K8/62

  Compositions for forming crevices or fractures · CPC title

• C09K8/80

  Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open · CPC title

• C09K8/592

  Compositions used in combination with generated heat, e.g. by steam injection · CPC title