Multi-stage geologic fracturing

Patent metadata

Field	Value
Publication number	US-10273792-B2
Application number	US-201414905356-A
Country	US
Kind code	B2
Filing date	Jul 15, 2014
Priority date	Jul 15, 2013
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

Explosive geologic fracturing methods, devices, and systems can be used in combination with other geologic fracturing means, such as hydraulic fracturing methods, devices and systems, or other fluid-based fracturing means. An exemplary method comprises introducing an explosive system into a wellbore in a geologic formation, detonating the explosive system in the wellbore to fracture at least a first portion of the geologic formation adjacent to the wellbore, and introducing pressurized fluid into the wellbore to enhance the fracturing of the first portion of the geologic formation. Such multi-stage fracturing can further enhance the resulting fracturing of geologic formation relative to explosive fracturing alone.

First claim

We claim:

1. A method of fracturing a geologic formation, comprising:
introducing an explosive system into a wellbore in a geologic formation, the explosive system comprising a plurality of longitudinally spaced apart explosive units;
positioning a plurality of longitudinally spaced apart explosive units along a first portion of the wellbore;
detonating the explosive system in the wellbore to fracture at least the first portion of the geologic formation adjacent to the wellbore, wherein detonating the explosive system comprises detonating the plurality of longitudinally spaced apart explosive units to produce a first rubblization zone radially adjacent to the first portion of the wellbore and along an entire longitudinal length of the first portion of the wellbore, and a second rubblization zone extending radially outwardly from the first portion of the wellbore radially beyond the first rubblization zone, the second rubblization zone being located longitudinally between an adjacent two of the plurality of longitudinally spaced apart explosive units;
redrilling the wellbore after detonating the explosive system to remove material from the wellbore; and
after detonating the explosive system and redrilling the wellbore, introducing pressurized fluid into the wellbore to enhance the fracturing of the first portion of the geologic formation.

2. The method of claim 1 , wherein introducing an explosive system into the wellbore comprises inserting an assembly of both explosive units and propellant units into the wellbore.

3. The method of claim 2 , wherein the detonation comprises creating a plurality of fractures in the first portion of the geologic formation and wherein the introduction of pressurized fluid into the wellbore comprises causing the pressurized fluid to enter into at least some of the plurality of fractures caused by the detonation and thereby increase the size, aperture, or extent of the fractures.

4. The method of claim 3 , wherein causing the pressurized fluid to enter into at least some of the plurality of fractures causes further expansion of a radius of fracturing from the wellbore into the geologic formation.

5. The method of claim 3 , wherein causing the pressurized fluid to enter into at least some of the plurality of fractures increases the permeability of the geologic formation beyond that provided by the explosive fracturing alone.

6. The method of claim 1 , wherein the pressurized fluid flows into the first and second rubblization zones and causes increased permeability of the geologic formation adjacent to the first and second rubblization zones.

7. The method of claim 1 , wherein the explosive units comprising tubular casings containing a first component of an explosive material, and the method further comprising introducing a second component of the explosive material into the casings after the casings are already positioned within the wellbore but before detonation of the explosive system.

8. The method of claim 7 , wherein introducing the second component of the explosive material into the casings comprises flowing the second component from a location outside of the wellbore to the casings.

9. The method of claim 8 , further comprising venting from the casing at the same time as the second component is flowing into the casings.

10. The method of claim 1 , wherein introducing the explosive system into the wellbore comprises inserting a plurality of casings for containing explosive material, the plurality of casing each comprising an elongated body comprising a wall having an interior surface and an exterior surface and comprising a casing material, wherein the plurality of casings are configured so as to prevent a substantially continuous and substantially impermeable coating of the wellbore by the casing material upon detonation of the explosive material.

11. The method of claim 10 , wherein the plurality of casings are configured to decompose upon detonation of the explosive material.

12. The method of claim 10 , wherein the plurality of casings comprise stress concentrations such that a tubular outer body of each casing is configured to fragment into a plurality of smaller pieces upon detonation of the explosive material.

13. The method of claim 1 , wherein pressurized fluid is not introduced into the wellbore before detonating the explosive system in the wellbore.

14. The method of claim 1 , wherein detonating the plurality of longitudinally spaced apart explosive units also produces a third rubblization zone extending radially outwardly from the first portion of the wellbore radially beyond the first rubblization zone, the third rubblization zone being located longitudinally between an adjacent two of the plurality of longitudinally spaced apart explosive units and being spaced longitudinally apart from the second rubblization zone.

15. The method of claim 1 , wherein the act of positioning further comprises positioning one or more working liquid containers intermediate to the positioned explosive units.

16. The method of claim 1 , further comprising positioning the explosive units based at least in part on the structure of the geologic formation along the first portion of the wellbore to produce spaced apart, disc-like, coalescing shock waves in the geologic formation upon detonation.

17. The method of claim 1 , wherein introducing pressurized fluid into the wellbore enhances the fracturing of the first rubblization zone and the second rubblization zone.

18. The method of claim 1 , wherein detonating the explosive units comprises the explosive units releasing a total energy equal to or greater than twelve kJ/cc and with greater than 30% of the energy released by the explosive units being released in the following flow Taylor Wave of the detonated explosive units.

Assignees

• Los Alamos Nat Security Llc
• Triad Nat Security Llc

Inventors

• Mace Jonathan Lee
• Bronisz Lawrence E
• Steedman David W
• Bradley Christopher Robert

Classifications

• F42B3/02

  adapted to be united into assemblies · CPC title

• F42D1/22

  Methods for holding or positioning for blasting cartridges or tamping cartridges · CPC title

• E21B43/263 Primary

  using explosives · CPC title

• E21B43/26

  by forming crevices or fractures · CPC title

• F42D3/00

  Particular applications of blasting techniques {(explosive welding B23K20/08; explosive bolts or actuators F42B3/006; explosive valves F16K13/06; cutting devices actuated by explosion B23D15/145; pyrotechnical actuators F15B15/19; switching devices actuated by explosion H01H39/00)} · CPC title