Numerical Simulation of Progressive CO2 Injection for Improved Coalbed Methane Extraction and Carbon Sequestration

Jiexu Lu; Hongjie Xu; Fugui Chen; Weidong Xiao; Jinwei Zhang; Jishou Hu

doi:10.54097/720jhb82

Authors

Jiexu Lu
Hongjie Xu
Fugui Chen
Weidong Xiao
Jinwei Zhang
Jishou Hu

DOI:

https://doi.org/10.54097/720jhb82

Keywords:

Numerical Simulation, Progressive CO2 Injection, Enhanced Coalbed Methane Recovery, CO2-CH4 Displacement, Carbon Capture and Storage

Abstract

A numerical simulation-based comparative analysis was conducted to investigate the displacement and extraction performance of coalbed methane (CH₄) under two CO₂ injection strategies: direct injection and progressive staged injection. Results show that direct CO₂ injection rapidly generates high-pressure zones, elevates reservoir pressure, and reduces permeability, leading to limited methane depletion and strong spatial heterogeneity in the extraction zone. In contrast, progressive CO₂ injection integrates staged pressurization with pressure-relief extraction, effectively lowering reservoir pressure, maintaining higher permeability, and significantly expanding the CH₄ extraction range. For both strategies, CH₄ recovery and CO₂ sequestration increased continuously with time; however, the progressive scheme achieved smoother and more efficient CH₄ production while sustaining sequestration effectiveness. After 300 days of injection and extraction, the average CH₄ content declined from 17.09 m³/t to 10.31 m³/t, yielding 1.69 × 10⁵ m³ of recovered CH₄ and 2.97 × 10⁵ m³ of sequestered CO₂. These findings demonstrate that progressive CO₂ injection can simultaneously enhance coalbed methane recovery and CO₂ geological storage, offering technical insights for efficient CBM development and mine gas control.

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References

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