Downhole stimulation tools and related methods of stimulating a producing formation

Patent metadata

Field	Value
Publication number	US-9995124-B2
Application number	US-201414491518-A
Country	US
Kind code	B2
Filing date	Sep 19, 2014
Priority date	Sep 19, 2014
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

A downhole stimulation tool comprising an outer housing exhibiting apertures extending therethrough, opposing propellant structures within the outer housing, and at least one initiator adjacent each of the opposing propellant structures. Each of the opposing propellant structures comprise at least one higher combustion rate propellant region, and at least one lower combustion rate propellant region longitudinally adjacent the at least one higher combustion rate propellant region. Additional downhole stimulation tools and methods of stimulating a producing formation are also disclosed.

First claim

What is claimed is:

1. A downhole stimulation tool, comprising:
a substantially monolithic outer housing comprising:
two regions free of apertures extending therethrough; and
an additional region longitudinally intervening between the two regions and exhibiting apertures extending therethrough;

opposing propellant structures substantially longitudinally confined within the two regions of the outer housing and each individually comprising:
at least one higher combustion rate propellant region; and
at least one lower combustion rate propellant region longitudinally adjacent the at least one higher combustion rate propellant region; and

at least one initiator adjacent each of the opposing propellant structures,
wherein the additional region of the substantially monolithic outer housing is substantially free of propellant structures contained therein prior to the ignition of the opposing propellant structures.

2. The downhole stimulation tool of claim 1 , wherein the at least one higher combustion rate propellant region comprises a plurality of higher combustion rate propellant regions, and the at least one lower combustion rate propellant region comprises a plurality of lower combustion rate propellant regions.

3. The downhole stimulation tool of claim 2 , wherein at least one of the plurality of higher combustion rate propellant regions exhibits a different volume of propellant than at least one other of the plurality of higher combustion rate propellant regions, and at least one of the plurality of lower combustion rate propellant regions exhibits a different volume of another propellant than at least one other of the plurality of lower combustion rate propellant regions.

4. The downhole stimulation tool of claim 1 , wherein each of the opposing propellant structures exhibits substantially the same longitudinal sequence of the at least one higher combustion rate propellant region and the at least one lower combustion rate propellant region extending in opposite directions from locations proximate a lateral axis of the outer housing.

5. The downhole stimulation tool of claim 1 , wherein each of the opposing propellant structures exhibits an alternating sequence of the at least one higher combustion rate propellant region and the at least one lower combustion rate propellant region beginning with the at least one higher combustion rate propellant region at a location proximate a lateral axis of the outer housing.

6. The downhole stimulation tool of claim 1 , wherein each of the opposing propellant structures further comprises at least one additional propellant region exhibiting a combustion rate different than combustion rates of the at least one higher combustion rate propellant region and the at least one lower combustion rate propellant region.

7. The downhole stimulation tool of claim 1 , wherein the at least one higher combustion rate propellant region of each of the opposing propellant structures exhibits at least one different volume of propellant than the at least one lower combustion rate propellant region of each of the opposing propellant structures.

8. The downhole stimulation tool of claim 1 , wherein the at least one initiator comprises:
a first initiator adjacent an end of one of the opposing propellant structures proximate a lateral axis of the outer housing; and
a second initiator adjacent an opposing end of another of the opposing propellant structures proximate the lateral axis of the outer housing.

9. The downhole stimulation tool of claim 1 , wherein the at least one initiator comprises a plurality of initiators adjacent the at least one higher combustion rate propellant region and the at least one lower combustion rate propellant region of each of the opposing propellant structures.

10. The downhole stimulation tool of claim 1 , wherein:
the additional region is located proximate a lateral axis of the outer housing; and
the outer housing further comprises at least two other regions each more longitudinally distal from the lateral axis of the substantially monolithic outer housing than the two regions and each exhibiting additional apertures extending therethrough.

11. A downhole stimulation tool, comprising:
an outer housing comprising:
a first structure free of apertures laterally extending therethrough;
a second structure free of apertures laterally extending therethrough; and
a third structure connected to and longitudinally interposed between the first structure and the second structure and exhibiting apertures extending therethrough;

a propellant structure substantially longitudinally confined within the first structure of the outer housing and comprising:
at least one higher combustion rate propellant region; and
at least one lower combustion rate propellant region adjacent the at least one higher combustion rate propellant region;

another propellant structure opposing the propellant structure and substantially longitudinally confined within the second structure of the outer housing, the another propellant structure comprising:
at least one other higher combustion rate propellant region; and
at least one other lower combustion rate propellant region adjacent the at least one other higher combustion rate propellant region; and

initiators adjacent each of the propellant structure and the another propellant structure,
wherein the additional region of the outer housing is substantially free of propellant structures contained therein prior to the ignition of the propellant structure and the another propellant structure.

12. The downhole stimulation tool of claim 11 , wherein the at least one higher combustion rate propellant region of the propellant structure exhibits substantially the same combustion rate as the at least one other higher combustion rate propellant region of the another propellant structure, and the at least one lower combustion rate propellant region of the first propellant structure exhibits substantially the same combustion rate as the at least one other lower combustion rate propellant region of the another propellant structure.

13. The downhole stimulation tool of claim 11 , wherein the at least one higher combustion rate propellant region of the propellant structure and the at least one other higher combustion rate propellant region of the another propellant structure each comprise a first propellant, and the at least one lower combustion rate propellant region of the propellant structure and the at least one other lower combustion rate propellant region of the another propellant structure each comprise a second, different propellant.

14. The downhole stimulation tool of claim 11 , wherein the at least one higher combustion rate propellant region of the propellant structure and the at least one other higher combustion rate propellant region of the another propellant structure each comprise at least one mutually different propellant.

15. The downhole stimulation tool of claim 11 , wherein the at least one lower combustion rate propellant region of the propellant structure and the at least one other lower combustion rate propellant region of the another propellant structure each comprise at least one mutually different propellant.

16. The downhole stimulation tool of claim 11 , wherein a sequence of the at least one higher combustion rate propellant region and the at least one lower combustion rate propellant region exhibited by the propellant structure is substantially the same as a sequence of the at least one other higher combustion rate propellant region and the at least one other lower combustion rate propellant region exhibi

Assignees

• Orbital Atk Inc

Inventors

• Moore Steven E
• Arrell John A

Classifications

• E21B33/124

  Units with longitudinally-spaced plugs for isolating the intermediate space · CPC title

• F42B3/04

  for producing gas under pressure {(generators of inflation fluid especially adapted for vehicle air bags B60R21/26)} · CPC title

• E21B43/263 Primary

  using explosives · CPC title

• E21B43/2605

  using gas or liquefied gas · CPC title