Foam Cavitation Coalbed Methane Stimulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for stimulating gas production from coalbed methane wells, such as hydraulic fracturing and cavitation, often cause damage to the coal seam and are less effective in wells with high permeability and low reservoir pressure, necessitating an improved method that minimizes damage and enhances production across various coal seam types.
Innovation Solution
A method involving the injection of a foam-forming liquid and an expandable fluid into a wellbore, followed by vaporization to create foam, which reduces pressure and fragments coal to form or enlarge cavities in the coal seam, thereby increasing gas production while minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic fracturing is used to stimulate gas production, then gas production is increased, but damage is caused to the natural cleat network in the coal seam
Solution Approach 1:
The patent utilizes phase transitions of foam (between liquid and gas phases) to create cavitation in the coal seam. The foam expands and collapses, fragmenting the coal and creating pathways for gas flow without the sustained high pressure of hydraulic fracturing, thereby avoiding damage to the natural cleat network while still increasing gas production.
Solution Approach 2:
The patent changes the pressure parameters by using foam that can rapidly expand and collapse, creating transient high pressure for cavitation followed by pressure release. This differs from hydraulic fracturing which maintains sustained high pressure, allowing the foam method to create pathways without continuously damaging the cleat network.
2Productivity
If cavitation is used to stimulate gas production, then gas production rates are increased, but effectiveness is limited in wells with high permeability and low reservoir pressure
Solution Approach 1:
The foam cavitation method is designed to be universally applicable to different well types including those with high permeability and low reservoir pressure. The foam's ability to expand and create cavitation pathways makes it effective across various coal seam conditions, not limited to specific permeability or pressure ranges.
3Productivity
If high pressure fluid injection is used for hydraulic fracturing, then pathways are created for gas travel, but coal fines combine with fluid to plug natural cleats
Solution Approach 1:
The patent uses foam (a pneumatic-hydraulic medium combining gas and liquid) instead of conventional hydraulic fracturing fluids. The foam creates cavitation pathways through expansion and collapse, avoiding the issue of coal fines combining with fluid to plug cleats, as the foam mechanism does not rely on fluid flow through the cleat network in the same manner.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances gas production rates by forming cavities without significant coal seam damage, effectively stimulating wells with high permeability and low reservoir pressure, and can be applied to various coal seam types.
Implementation Method 1
vaporizing at least a portion of the injected expandable fluid to thereby form an expanded gas
Implementation Method 2
the vaporizing of the expandable fluid causes the formation of a foam from at least a portion of the expanded gas and at least a portion of the first foam forming liquid
Implementation Method 3
cavitation involves the formation and/or enlargement of a cavity in the near wellbore region of the coal seam... fragmenting a portion of the coal, which creates and/or enlarges a cavity in the coal seam
Implementation Method 4
hydraulic fracturing involves introducing a fracturing fluid into the coal seam at a pressure above the fracture pressure of the coal formation
Data Source
AI summary
A method of stimulating gas production from a coalbed methane well that involves injecting a foam forming liquid and an expandable fluid into a coal seam proximate the wellbore. When the wellbore pressure is reduced, at least a portion of the expandable fluid can vaporize, which can generate foam that aids in the formation and/or enlargement of a cavity in the coal seam proximate the wellbore.