Coalbed Methane Extraction via Pressure Arch Identification
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Solution Overview
Problem
The challenge is to identify and extract coalbed methane from secondary reservoir formations in abandoned mines, as methane escapes into the atmosphere, posing safety risks and wasting a valuable energy resource, while existing methods fail to accurately determine pressure arches and optimize extraction strategies.
Innovation Solution
A method involving classification of overlying strata failure types, three-dimensional modeling, stress distribution analysis, and asymptotic failure characteristic calculations to identify pressure arches and optimize the placement of surface wells for combined extraction, using a specific cementing material to ensure wellbore stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional extraction methods are used in abandoned mines, then extraction simplicity is maintained, but extraction efficiency and safety are insufficient due to inability to accurately identify pressure arches and secondary reservoir formations
Solution Approach 1:
The patent segments the complex extraction system into distinct functional modules: pressure arch identification module, secondary reservoir formation boundary identification module, and combined extraction module. This segmentation allows each module to perform its specific function independently, improving overall extraction efficiency while maintaining system manageability through modular architecture.
Solution Approach 2:
The patent introduces a new dimensional approach by transitioning from traditional two-dimensional extraction planning to three-dimensional spatial analysis. This involves calculating pressure arch positions in multiple dimensions and identifying secondary reservoir formations at different depths, enabling more precise target identification and improving extraction efficiency through spatial optimization.
2Productivity
If multiple separate extraction wells are used for multiple mine faces, then extraction simplicity is maintained, but land use efficiency and extraction coordination are reduced
Solution Approach 1:
The patent merges multiple extraction operations into a single coordinated extraction system. By identifying and connecting multiple pressure arches and secondary reservoir formations through one surface well, the system achieves combined extraction from multiple mine faces simultaneously. This merging reduces the total surface well area required while improving extraction coordination efficiency through unified control and monitoring.
Solution Approach 2:
The single surface well is designed with multi-functionality to serve multiple purposes: extracting coalbed methane from different mine faces, monitoring pressure arch developments, and coordinating extraction operations across multiple locations. This universal design allows one well to perform functions that would traditionally require multiple separate wells, reducing land use while maintaining or improving extraction efficiency.
3Measurement precision
If pressure arch boundaries are not accurately identified, then extraction simplicity is maintained, but extraction precision and safety are compromised due to uncertain secondary reservoir formation positions
Solution Approach 1:
The patent applies preliminary action by performing comprehensive stress distribution calculations and pressure arch identification before the actual extraction operation. The system calculates stress fields, identifies pressure arch positions, and determines secondary reservoir formation boundaries in advance. This preliminary analysis provides precise guidance for well placement and extraction parameters, improving measurement precision while the systematic approach manages complexity through structured computation steps.
Solution Approach 2:
The patent replaces traditional mechanical or empirical methods for pressure arch identification with computational mechanics and mathematical modeling. By using stress field calculations, constitutive models, and numerical simulations, the system achieves more precise pressure arch boundary identification. This substitution of mechanical/empirical approaches with computational methods improves measurement precision while managing complexity through algorithmic processing and automated calculations.
Data Source
AI summary
Disclosed is a method for identifying secondary reservoir formation boundaries and combined extraction of multiple asymmetric mining coalbed methane. This method fully combines the displacement transfer mechanism after multiple mining to determine its influence on a horizontal thrust of overlying strata after a first mining, and then determines evolution characteristics of pressure arches. Combining the identification of different types of pressure arches with a layout of a surface well accurately determines a secondary reservoir formation range of coalbed methane. By adopting the method of mining face overlying strata in series for combined extraction, coalbed methane from multiple mine faces is extracted by one well to greatly improve the coalbed methane extraction effect.