Methods and apparatus for downhole propellant-based stimulation with wellbore pressure containment
AssigneeOrbital ATK, Inc.
InventorsSteven E. Moore, John A. Arrell, Jr.
Life of this patent
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Abstract
Downhole stimulation tools include a housing and at least one propellant structure within the housing comprising at least one propellant grain of a formulation, at least another propellant grain of a formulation different from the formulation of the at least one propellant grain longitudinally adjacent the at least one propellant grain, and at least one initiation element proximate at least one of the propellant grains. At least one pressure containment structure is secured to the housing and comprises a seal element expandable in response to gas pressure generated by combustion of a propellant grain of the at least one propellant structure. Related methods are also disclosed.
Claims21
A downhole stimulation tool, comprising:
- a housing;
- propellant structures within the housing and each individually comprising a heterogeneous stack of propellant regions configured and positioned to burn in sequence with one another upon ignition of the propellant structures, the propellant regions each individually comprising:
- at least one propellant grain extending across at least a majority of a lateral cross-sectional area of the housing and having a first chemical composition;
- and
- at least one other propellant grain longitudinally adjacent the at least one propellant grain and extending across at least a majority of the lateral cross-sectional area of the housing, the at least one other propellant grain having a second chemical composition different than the first chemical composition;
- at least one initiation element proximate one or more of the at least one propellant grain and the at least one other propellant grain of each of the propellant structures;
- and
- at least one pressure containment structure secured to the housing and comprising a seal element expandable in response to gas pressure generated by combustion of at least one of the propellant structures.
A method of operating a downhole stimulation tool, the method comprising:
- deploying the downhole stimulation tool within a wellbore adjacent a producing formation, the downhole stimulation tool comprising:
- a housing;
- propellant structures within the housing and each individually comprising a heterogeneous stack of propellant regions configured and positioned to burn in sequence with one another upon ignition of the propellant structures, the propellant regions each individually comprising:
- at least one propellant grain extending across at least a majority of a lateral cross-sectional area of the housing and having a first chemical composition;
- and
- at least one other propellant grain longitudinally adjacent the at least one propellant grain and extending across at least a majority of the lateral cross-sectional area of the housing, the at least one other propellant grain having a second chemical composition different than the first chemical composition;
- at least one initiation element proximate one or more of the at least one propellant grain and the at least one other propellant grain of each of the propellant structures;
- and
- at least one pressure containment structure secured to the housing and comprising a seal element expandable in response to gas pressure generated by combustion of at least one of the propellant structures;
- initiating the propellant structures from faces thereof to burn the at least one propellant grain and the at least one other propellant grain of each of the propellant structures in a longitudinally extending direction and generate gas pressure for stimulating the producing formation;
- transmitting a portion of the gas pressure generated by combusting at least one of the propellant structures of the downhole stimulation tool to expand at least one seal element of at least one pressure containment structure secured to a housing of the downhole stimulation tool;
- and elevating pressure within the wellbore to stimulate the producing formation with a remaining portion of the generated gas pressure.
Dependencies are inferred from the claim text.