Heating Well Expansion Pillar for Coalbed Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for enhancing hydrocarbon production from coalbeds are limited by the low permeability of deep coalbeds, which restricts commercial production rates, and depressurization techniques often lead to reduced permeability and high energy costs for compressing low-pressure gas.
Innovation Solution
The method involves using a heating well to apply heat to the subsurface formation near the coalbed, creating an expansion pillar that reduces overburden stress, thereby increasing permeability and allowing for enhanced hydrocarbon production through the formation of fractures and directional drilling of production wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If depressurization is used to produce CBM from coalbeds, then gas production is achieved, but permeability decreases due to cleat collapse
Solution Approach 1:
The patent applies preliminary anti-action by injecting gas at high pressure before production to prevent cleat collapse. The injection pressure is maintained above the minimum fracturing pressure to keep cleats open, counteracting the natural tendency of cleats to collapse during depressurization. This preventive measure ensures permeability is maintained throughout the production process.
Solution Approach 2:
The patent implements dynamics by continuously adjusting injection and production pressures to maintain cleat openness. The system dynamically balances injection pressure (to keep cleats open) with production pressure (to enable gas flow), adapting operating conditions to prevent permeability loss while maximizing production.
2Quantity of substance
If depressurization is used to produce CBM, then gas can be extracted, but low-pressure gas requires significant compression energy
Solution Approach 1:
The patent applies preliminary action by injecting gas at high pressure into the coalbed before production begins. This pre-pressurization maintains cleat openness and creates a pressure gradient that enables gas flow at higher pressures, reducing the need for subsequent compression and lowering energy requirements for gas transportation.
3Reliability
If cavitation is used to improve permeability, then some CBM production is achieved, but only a small fraction is economically recoverable
Solution Approach 1:
The patent replaces the mechanical cavitation process with a pressure maintenance system using continuous gas injection. Instead of using rapid pressure cycling to create cavities, the system uses sustained high-pressure injection to keep cleats open, providing more consistent and effective permeability enhancement for economic gas recovery.
Solution Approach 2:
The patent changes the pressure parameter from cyclic (cavitation) to sustained high pressure (injection above minimum fracturing pressure). This parameter change maintains cleat openness continuously rather than temporarily, significantly improving the fraction of economically recoverable gas compared to cavitation methods.
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 increases hydrocarbon recovery by expanding cleat systems in coalbeds, improving gas flow and reducing energy costs associated with compressing low-pressure gas for transportation.
Implementation Method 1
heating the subsurface formation via the heating source to form an expansion pillar
Implementation Method 2
Fractures may be created in the subsurface formation in proximity to the reservoir via the expansion pillar
Data Source
AI summary
A method for enhancing hydrocarbon recovery from a reservoir using a heating well to reduce overburden stress over portions of the reservoir and the heating well is located in a subsurface formation proximate to the reservoir. The method may include heating the subsurface formation via the heating well above the reservoir, below the reservoir, or both, to form an expansion pillar and producing a hydrocarbon from the reservoir.