成果归属作者：

赵二猛

成果归属机构：

能源学院

作者：

Hu, Jiangtao ; Yang, Shenglai ; Bi, Lufei ; Gao, Xinyuan ; Deng, Hui ; Zhao, Ermeng

单位：

China Univ Petr, State Key Lab Petr Resources & Prospecting, Beijing 102249, Peoples R China;PetroChina Southwest Oil & Gasfield Co, Explorat & Dev Res Inst, Chengdu 610041, Peoples R China;China Univ Geosci Beijing, Sch Energy Resource, Beijing 100083, Peoples R China;Peking Univ, Ordos Res Inst Energy, Ordos 017010, Peoples R China

关键词：

SEQUESTRATION; SIMULATION; WATER; MECHANISM; FLOW

摘要：

Injecting CO2 into depleted gas reservoirs can achieve CO2 geological storage and enhance CH4 recovery (CSEGR), offering both engineering and environmental benefits. Low-permeability carbonate gas reservoirs are characterized by poorly developed large-scale pores, short stable production periods for individual wells, rapid production decline, and low recovery rate during depletion development. Based on the reservoir characteristics of low permeability carbonate gas reservoir of Dengying Formation in Anyue gas field, this study developed a comprehensive numerical simulation model that considers CO2 dissolution, diffusion, permeability-stress sensitivity, high-speed non-Darcy flow, and multiple CO2 storage mechanisms. The study systematically examines horizontal well location deployment strategies, CO2 injection rates, and reservoir heterogeneity. The numerical simulation results show that deploying CO2 injection wells in high-permeability Type-I reservoirs achieves the best balance between improving CH4 recovery, CO2 storage, and injection safety, making it the optimal well deployment strategy. This scheme results in a CH4 recovery rate of 5.12 % and a CO2 storage capacity of 5.52 x 108 m3. Although the low-speed decreasing-rate CO2 injection scheme has a limited CO2 sweep range and lower CO2 storage, it results in the highest enhanced CH4 recovery and the most balanced reservoir pressure distribution, making it the optimal CO2 injection strategy. With this CO2 injection mode, the FPVC value corresponding to an injection rate of 15 x 104 m3/d is only 40.20 %, but it achieves a CH4 recovery rate of up to 6.41 %. The along-wellbore heterogeneity influences CO2 flow paths and pressure gradients. Type-I reservoirs near production wells enable higher CH4 recovery but lead to earlier CO2 breakthrough. Perpendicular heterogeneity analysis shows that placing Type-II reservoirs between the production and injection wells delays CO2 breakthrough and increases CO2 storage, though it may require unfeasibly high injection pressures. Optimizing reservoir connectivity and aligning high-permeability zones with production wells are crucial for maximizing CH4 recovery and CO2 storage volume in heterogeneous carbonate reservoirs.

基金：

Sichuan Provincial Natural Science Foundation Project [2023NSFSC0261]; National Natural Science Foundation of China [52304018]; Natural Science Foundation of Inner Mongolia Autonomous Region of China [2025MS05008]; Fundamental Research Funds for the Central Universities [2-9-2024-042]

语种：

英文

DOI：

10.1016/j.fuel.2025.136397

来源：

FUEL,2026():.

出版日期：

2026-01-15

提交日期：

2025-08-21

引用参考：

Hu, Jiangtao; Yang, Shenglai; Bi, Lufei; Gao, Xinyuan; Deng, Hui; Zhao, Ermeng. Numerical modeling of CO2 storage and gas recovery enhancement in low-permeability carbonate reservoirs via acid-fractured horizontal wells[J]. FUEL,2026():.