CO2 geological storage in deep coal has become one of the important means for unconventional energy gas injection and production enhancement,as well as achieving regional carbon negative emission targets. Five coal-accumulating units in the Caoxian and Shanxian coalfields of southwest Shandong were focused,targeting the Shanxi Formation No.3 deep coal seam,to explore the potential of CO2 geological storage in different coal-bearing units. Firstly,based on the supercritical carbon dioxide phase state mechanism,the critical depth for CO2 storage in the target coal seam was defined,and the feasibility of CO2 geological storage was discussed. Secondly,the blocks and units for CO2 geological storage were divided according to the principle of decreasing order of structure(faults and folds)and burial depth.On this basis,the calculation of CO2 adsorption capacity and free gas content was carried out in units of storage cells. Finally,the main controlling factors of CO2 geological storage were identified by using the analytic hierarchy process(AHP)and principal component analysis(PCA). And a fuzzy comprehensive evaluation system was used to divide the favorable areas for deep coal seam CO2 geological storage in southwestern Shandong Province. The findings show that the structural conditions of the deep coal seams in the Caoxian and Shanxian coalfields are relatively simple,with the coal seam burial depths of 800~2 000 m(reaching the critical depth of supercritical state CO2 geological storage),providing good conditions for CO2 storage. The main controlling factors of the effectiveness of deep coal seam CO2 geological storage are permeability and porosity. Through the fuzzy comprehensive evaluation system,it is determined that there are 6 blocks in the Caoxian coalfield,and the blocks is categorized into three classes of favorable areas. Class I advantage areas are blocks 2 and 5,with the sequestration capacity of 244 Mt and the sequestration area of 310.65 km2. Class II advantage areas are blocks 1 and 6,with the sequestration capacity of 191.7 Mt and the sequestration area of 248.63 km2. Class III advantage areas are blocks 3 and 4,with the sequestration capacity of 79.83 Mt and the sequestration area of 101.39 km2,indicating its for CO2 geological storage potential is the greatest.
LIU Xin-yue, ZHANG Jun-jian, YANG Bin, WANG Meng, MIAO He-yao, TANG Lu-lu, CHANG Xiang-chun, LÜ Da-wei, WANG Dong-dong, WANG Jin-kai.
Division of Carbon Dioxide Geological Storage Units and Evaluation of Storage Potential in Deep Coal Seams in Southwest Shandong Province[J].
Science Technology and Engineering, 2026, 26(4): 1423-1436 DOI:10.12404/j.issn.1671-1815.2501373
ShenJian, QinYong, ZhangChunjie, et al. Feasibility of enhanced coalbed methane recovery by CO2 sequestration into deep coalbed of Qinshui Basin[J]. Journal of China Coal Society, 2016, 41(1): 156-161.
CaoCheng, ChenXingyu, ZhangLiehui, et al. Research progress on CO2 injection for enhanced oil recovery and storage evaluation in gas reservoirs[J]. Science Technology and Engineering, 2024, 24(18): 7463-7475.
SangShuxun. Review on the effectiveness of carbon dioxide geological storage and CBM enhanced development[J]. Coalfield Geology and Exploration, 2018, 46(5): 1-9.
HanSijie. CO2 storage mechanism and storage potential evaluation method of CO2-ECBM in deep anthracite reservoir[D]. Beijing: China University of Mining and Technology-Beijing, 2020.
[11]
TalapatraA. A study on the carbon dioxide injection into coal seam aiming at enhancing coal bed methane(ECBM)recovery[J]. Journal of Petroleum Exploration and Production Technology, 2020, 10(5): 1965-1981.
YaoYanbin, SunXiaoxiao, WanLei. Study on microscopic mechanism of CO2 geological storage in coal seams[J]. Coalfield Geology and Exploration, 2023, 51(2): 146-157.
HanSijie, SangShuxun, DuanPiaopiao, et al. Improved evaluation methodof CO2 geological storage potential in deep coal seams: a case study of 3# coal seam in Zhengzhuang block, Qinshui Basin[J]. Journal of China University of Mining and Technology, 2023, 52(4): 772-788.
SangShuxun, LiuShiqi, WangWenfeng, et al. Theory and evaluation of the effectiveness of CO2 geological storage and CBM enhanced development in deep coal seams[M]. Beijing: Science Press, 2020: 403-435.
[18]
BachuS, AdamsJ. Sequestrationof CO2 in geological media in response to climate change: capacity of deep saline aquifers to sequester CO2 in solution[J]. Energy Conversion and Management, 2003, 44: 3151-3175.
[19]
BachuS, BonijolyD, BradshawJ, et al. CO2 storage capacity estimation: methodology and gaps[J]. International Journal of Greenhouse Gas Control, 2007, 1(4): 430-443.
WangYi, YangWeifeng, ZhangXuguang, et al. Fuzzy comprehensive evaluation of CO2 sequestration stability in deep unmined coal seams[J]. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(S1): 2932-2939.
LiuCao, ZhaoChunhui, ZhongFuping, et al. Quantitative evaluation and case study of CO2 geological sequestration in deep coal seams[J]. Coal Science and Technology, 2024, 52(S1): 288-298.
[24]
BachuS. CO2 storage in geological media: role, means, status and barriers to deployment[J]. Progress in Energy and Combustion Science, 2008, 34(2): 254-273.
[25]
ChadwickrA, ArtsrS, BenthamM, et al. Review of monitoring issues and technologies associated with the long-term underground storage of carbon dioxide[J]. Geological Society, 2009, 313(1): 257-275.
SangShuxun, LiuShiqi, ZhuQianlin, et al. Research progress on the technical basis of the synergy between CO2 geological sequestration potential and energy resources[J]. Journal of China Coal Society, 2023, 48(7): 2700-2716.
LiuShiqi, HuangFansheng, DuRuibin, et al. Progress of demonstration projects on CO2 geological sequestration and utilization and analysis of typical cases[J]. Coal Geology & Exploration, 2023, 51(2): 158-174.
ZhangJunjian, ChangXiangchun, LüDawei, et al. Research and evaluation of CO2 geological sequestration in coal seam development areas under the dual carbon goals[J]. Coal Science and Technology, 2023, 51(S1): 206-214.
[32]
ZhanJ, ChenZ X, ZhangY, et al. Will the future of shale reservoirs lie in CO2 geological sequestration[J]. Science China Technological Sciences, 2020, 63(7): 1154-1163.
[33]
ZhanJ, NiuZ, LiM, et al. Numerical simulation and modeling on CO2 sequestration coupled with enhanced gas recovery in shale gas reservoirs[J]. Geofluids, 2021: 9975296.
YuDeming, LiuHaiyan, WangDongdong, et al. Analysis of coal type distribution and coal metamorphism types in southwestern Shandong Province[J]. Geological Survey of China Coal, 2015, 27(10): 6-9.
LuPing, BaiYong, LiuWeigang, et al. Optimization of favorable areas for CO2 geological sequestration in the Majiagou Formation of the Ordos Basin[J]. Geological Review, 2021, 67(3): 816-827.
LeiXiaoqiao, ZhouRiping. Tectonic evolution and coal metamorphism regularities in the southwestern Shandong region[J]. Geological Survey of China Coal, 2018, 30(7): 22-24, 71.
WuYanling, GeDongfeng. Fine description of the heterogeneity of the pore and fracture structure of CBM reservoirs based on theintrusive-extrusive curves of high-pressure mercury injection[J]. Geological Survey of China Coal, 2024, 36(10): 28-38.
LiuJiajia, ZhangYunlong, YangDi, et al. Joint characterization of pores and fractures in medium and low-rank coals based on mercury injection-nitrogen adsorption-nuclear magnetic resonance methods[J]. Journal of Henan Polytechnic University (Natural Science), 2025, 44(2): 19-31.
LiuKe. A new method for characterizing the pore-throat structure of tight sandstones based on nuclear magnetic resonance and constant-rate mercury injection[J]. Special Oil & Gas Reservoirs, 2025, 32(1): 135-143.
[46]
张鑫淼. 典型尺度煤体的孔裂隙结构表征与变化规律研究[D]. 焦作: 河南理工大学, 2020.
[47]
ZhangXinmiao. Research on the characterization and variation law of pore and fracture structure of coal bodies at typical scales[D]. Jiaozuo: Henan Polytechnic University, 2020.
XiaoFuqiang, ZouYongjun, ZhangShuanglong, et al. Study on the adsorption characteristics and adsorption models of CH4 and CO2 in the coal seams of the Leping Formation in the Fengcheng mining area[J]. Safety in Coal Mines, 2025, 56 (1): 43-51.
TianZhengjun, ZhuGuowei. Statistical analysis and application of fracture fractal dimension values based on MAPGIS[J]. Coal and Chemical Industry, 2021, 44(3): 41-43, 47.
WeiJiuchuan, ZhaoLei, YinHuiyong, et al. Analysis of the fractal characteristics of fault structures in the 19# coal seam of the Donggang minefield in the Laiwu coalfield[J]. China Coal, 2010, 36(4): 71-74, 80.
LiCuifang. Analysis of the resource potential of shale gas in the Carboniferous-Permian coal measures in the southwestern Shandong region[J]. Geological Survey of China Coal, 2020, 32(10): 15-21.
LiuCao, YanJiangwei, ZhaoChunhui, et al. Mechanism of supercritical CO2 desorption hysteresis in coal and its implications for geological sequestration[J]. Journal of China Coal Society, 2024, 49(7): 3154-3166.
WenHang, JiangXingwen, XuDonghua. Research status and prospect of fractures in supercritical carbon dioxide fracturing[J]. Science Technology and Engineering, 2020, 20(17): 6703-6710.
JiYoujun, WangXiaoyang, ZhouTiyao, et al. Influence of CO2 geological sequestration under multi-field coupling on reservoir mechanical properties and gas migration and diffusion[J]. Environmental Engineering, 2023, 41(S2): 442-446.
LiuShiqi, FangHuihuang, SangShuxun, et al. Numerical simulation study on CO2-ECBM in coal seams based on multi-physical field coupling solution[J]. Coal Science and Technology, 2019, 47(9): 51-59.
ZhengXuezhao, CaoChengyu. Simulation study on the change of CH4 gas inside coal media during CO2 displacement[J]. Contemporary Chemical Research, 2022(19): 1-6.
YuPeng, YangFulin, OyinkepreyeDavid Orodu, et al. Optimizationof CO2 flooding injection parameters in high water cut period in low-permeability reservoirs: a case study of S-95 block in Damintun Sag[J]. Science Technology and Engineering, 2020, 20(8): 3029-3034.