PULSE FRACTURING DEVICE AND METHOD

• US 20120279713A1
• Filed: 07/13/2012
• Published: 11/08/2012
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: LEON, Jean-Francis, FRAM, Joseph Henry
• Granted Patent: US 8,596,349 B2
• Time in Patent Office: Days
• US Class Current: 166/303
• CPC Class Codes: E21B 28/00 Vibration generating arrangements for boreholes or wells, e.g. for stimulating production for fishing for or freeing objects E21B31/005; for transmitting measuring-signals E21B47/14; for geophysical measurements G01V1/02
• CPC Class Codes: E21B 33/124 Units with longitudinally-spaced plugs for isolating the intermediate space
• CPC Class Codes: E21B 43/003 Vibrating earth formations
• CPC Class Codes: E21B 43/2405 in association with fracturing or crevice forming processes E21B43/247 takes precedence
• CPC Class Codes: E21B 43/26 by forming crevices or fractures
• CPC Class Codes: G01V 1/157 using spark discharges; using exploding wires

Abstract

A method of inducing fracture in at least a portion of a geologic structure includes inducing acoustic waves into a fluid medium present in a borehole extending at least partially into the structure. Embodiments may include preheating or pressurizing the fluid medium prior to inducing the acoustic wave therein.

Claims

1. A method of inducing fracture in at least a portion of a geologic structure, comprising:

generating an acoustic wave in a fluid medium present in a borehole penetrating at least partially into the geologic structure, the acoustic wave being an ordinary acoustic wave having frequency, duration and amplitude sufficient to induce fracture in the portion of the geologic structure; and

injecting pressurized fluid into a region proximate an electrode used to generate the acoustic wave.

2. A method as in claim 1, further comprising, creating a temperature gradient in a portion of the fluid medium proximate the electrode and having a peak temperature below a boiling point of the fluid medium.

3. A method as in claim 2, wherein the temperature below the boiling point of the fluid is a temperature within about 10% of the boiling point of the fluid medium.

4. A method as in claim 1, further comprising, wherein the pressurized fluid is a heated pressurized fluid and the injecting creates a temperature gradient in a portion of the fluid medium having a peak temperature below a boiling point of the fluid medium.

5. A method as in claim 4, wherein the fluid is injected through an aperture in the electrode.

6. A method as in claim 1, wherein the injecting pressurized fluid comprises pressurizing the fluid in the borehole to a pressure below a threshold pressure above which the geologic structure would fracture prior to generating the acoustic wave.

7. A method as in claim 6, wherein the pressure below the threshold pressure is a pressure within about 10% of the threshold pressure.

8. A method as in claim 1, wherein the generating the acoustic wave comprises generating a spark discharge within the fluid to form an expanding gas bubble that exerts pressure on the fluid to generate the acoustic wave.

9. A method as in claim 1, further comprising, repeating the generating at a frequency below about 10 Hz.

10. A method as in claim 1, wherein the generating comprises generating an electrical discharge within the fluid wherein a current of the discharge squared is greater than 3% of a peak value of the current of the discharge squared for more than 100 μ

s.

11. A method as in claim 1, further comprising injecting an agent into the fluid medium, the agent being selected to improve flowability of a material present in the geologic structure.

12. A method as in claim 11, wherein the agent comprises a chemical additive.

13. A method as in claim 12, wherein the chemical additive is an agent for inducing rock fracture.

14. A method as in claim 13, wherein the additive comprises steam.