Downhole Stimulation Tool with Opposing Propellant Structures
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Solution Overview
Problem
Conventional propellant-based downhole stimulation tools lack the ability to controllably vary pressure within a producing formation over an extended period, and they are not easily reusable or designed to minimize movement during operation.
Innovation Solution
The use of a downhole stimulation tool with opposing propellant structures featuring higher and lower combustion rate regions, housed in an outer structure with strategically placed apertures, allows for controlled pressure variation by initiating combustion from multiple points to manage pressure pulses over time, minimizing tool movement and enabling reusability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional propellant-based downhole stimulation tools use a single type of propellant with uniform combustion rate, then the tool structure is simple and easy to manufacture, but the pressure within the producing formation cannot be controllably varied over an extended period of time
Solution Approach 1:
The propellant is divided into multiple discrete sticks or segments, each with different combustion rates. This segmentation allows independent control of pressure generation phases: high combustion rate sticks provide initial pressure surge while low combustion rate sticks sustain pressure over extended periods (1-60+ seconds), resolving the contradiction between duration and complexity
Solution Approach 2:
Different regions of the propellant structure have different combustion rates - high combustion rate propellant in certain sticks for rapid pressure buildup, and low combustion rate propellant in other sticks for sustained pressure. This local differentiation enables controllable pressure variation over time without requiring complex mechanical systems
2Ease of manufacture
If conventional propellant-based stimulation tools are designed for single use, then the structure can be optimized for one-time high pressure delivery, but the tool cannot be reused and operational costs increase
Solution Approach 1:
The tool incorporates a movable outer housing that can transition between closed and open positions. After deployment, the housing moves to a retracted position that minimizes interference with wellbore operations while maintaining seal integrity. This dynamic positioning enables the tool to be retrieved, refurbished, and reused multiple times without compromising reliability
Solution Approach 2:
The tool is designed to be recovered after use rather than discarded. The outer housing and internal components are configured to withstand the stimulation process and can be retrieved, inspected, and prepared for subsequent deployments, reducing operational costs and improving sustainability
3Stress or pressure
If conventional propellant-based stimulation tools are deployed in wellbores, then they can deliver high pressure gases to stimulate the formation, but the tools experience movement during operation that reduces precision and effectiveness
Solution Approach 1:
The tool employs a balanced configuration where opposing propellant sticks are positioned to generate thrust forces that counterbalance each other. This anti-thrust design prevents the tool from moving or rotating during propellant combustion, maintaining stable positioning in the wellbore while delivering the required pressure to the formation
Data Source
AI summary
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.