Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin
The 8# thick coal seam is widely distributed with high organic matter thermal maturity at the top of the Upper Carboniferous Benxi Formation in the M area of the Ordos Basin. However, the coal seams in this area are characterized by large burial depth, rapid lateral changes, strong heterogeneity, an...
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Editorial Office of Petroleum Geology and Experiment
2025-01-01
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| Series: | Shiyou shiyan dizhi |
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| Online Access: | https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025010017 |
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| author | Xiaojiao GUO Lei WANG Xianzhou YAO Xu LI Linke ZHANG Xiaoshuang WANG |
| author_facet | Xiaojiao GUO Lei WANG Xianzhou YAO Xu LI Linke ZHANG Xiaoshuang WANG |
| author_sort | Xiaojiao GUO |
| collection | DOAJ |
| description | The 8# thick coal seam is widely distributed with high organic matter thermal maturity at the top of the Upper Carboniferous Benxi Formation in the M area of the Ordos Basin. However, the coal seams in this area are characterized by large burial depth, rapid lateral changes, strong heterogeneity, and unclear basic geological features and enrichment patterns of deep coalbed methane (CBM). The criteria for selecting favorable targets are yet to be established. These severely restrict the efficient exploration of deep CBM. To promote increased reserves and efficient production of deep CBM, and to further develop the enrichment theory of deep CBM in the eastern Ordos Basin, a comprehensive study was conducted based on core observations, experimental tests, scanning electron microscopy, well logging data from 76 wells in the study area, and 3D seismic data. The geological characteristics of deep coal seams and the main controlling factors of CBM enrichment were investigated, preliminary clarifying the exploration potential of this area. The results indicate that: The 8# coal seam at the top of the Upper Carboni-ferous Benxi Formation in the M area of the Ordos Basin is mainly composed of coking coal and lean coal, which are medium to high-ranked coals. The thickness of bright coal and semi-bright coal ranges from 2 to 6 m. Organic components are mainly vitrinite, accounting for 79.8%. Industrial components exhibit medium to high levels of volatile matter and ash, abundant fixed carbon, and low moisture content. The coal rock reservoir has well-developed pores and fractures, primarily composed of micropores and macropores. Gas content ranges between 16-25 m3/t. The enrichment of deep CBM in the eastern margin of the Ordos Basin is mainly controlled by coal reservoir and structural factors. Favorable exploration areas for deep CBM include regions with coal seams thicker than 6 m, areas with developed fractures far from fault zones (fault displacement less than 5 m), and microstructure high points. Based on these criteria, a favorable exploration area of 207 km2 for the 8# coal seam was identified, with 97 km2 classified as Type Ⅰ and 110 km2 as Type Ⅱ. |
| format | Article |
| id | doaj-art-4a7b95382c31429da99a28b3d37b7773 |
| institution | Kabale University |
| issn | 1001-6112 |
| language | zho |
| publishDate | 2025-01-01 |
| publisher | Editorial Office of Petroleum Geology and Experiment |
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| series | Shiyou shiyan dizhi |
| spelling | doaj-art-4a7b95382c31429da99a28b3d37b77732025-02-09T07:48:48ZzhoEditorial Office of Petroleum Geology and ExperimentShiyou shiyan dizhi1001-61122025-01-01471172610.11781/sysydz2025010017sysydz-47-1-17Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos BasinXiaojiao GUO0Lei WANG1Xianzhou YAO2Xu LI3Linke ZHANG4Xiaoshuang WANG5School of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, ChinaChangqing Branch, Geophysical Research Institute, BGP INC., CNPC, Xi'an, Shaanxi 710021, ChinaChangqing Branch, Geophysical Research Institute, BGP INC., CNPC, Xi'an, Shaanxi 710021, ChinaChangqing Branch, Geophysical Research Institute, BGP INC., CNPC, Xi'an, Shaanxi 710021, ChinaChangqing Branch, Geophysical Research Institute, BGP INC., CNPC, Xi'an, Shaanxi 710021, ChinaChangqing Branch, Geophysical Research Institute, BGP INC., CNPC, Xi'an, Shaanxi 710021, ChinaThe 8# thick coal seam is widely distributed with high organic matter thermal maturity at the top of the Upper Carboniferous Benxi Formation in the M area of the Ordos Basin. However, the coal seams in this area are characterized by large burial depth, rapid lateral changes, strong heterogeneity, and unclear basic geological features and enrichment patterns of deep coalbed methane (CBM). The criteria for selecting favorable targets are yet to be established. These severely restrict the efficient exploration of deep CBM. To promote increased reserves and efficient production of deep CBM, and to further develop the enrichment theory of deep CBM in the eastern Ordos Basin, a comprehensive study was conducted based on core observations, experimental tests, scanning electron microscopy, well logging data from 76 wells in the study area, and 3D seismic data. The geological characteristics of deep coal seams and the main controlling factors of CBM enrichment were investigated, preliminary clarifying the exploration potential of this area. The results indicate that: The 8# coal seam at the top of the Upper Carboni-ferous Benxi Formation in the M area of the Ordos Basin is mainly composed of coking coal and lean coal, which are medium to high-ranked coals. The thickness of bright coal and semi-bright coal ranges from 2 to 6 m. Organic components are mainly vitrinite, accounting for 79.8%. Industrial components exhibit medium to high levels of volatile matter and ash, abundant fixed carbon, and low moisture content. The coal rock reservoir has well-developed pores and fractures, primarily composed of micropores and macropores. Gas content ranges between 16-25 m3/t. The enrichment of deep CBM in the eastern margin of the Ordos Basin is mainly controlled by coal reservoir and structural factors. Favorable exploration areas for deep CBM include regions with coal seams thicker than 6 m, areas with developed fractures far from fault zones (fault displacement less than 5 m), and microstructure high points. Based on these criteria, a favorable exploration area of 207 km2 for the 8# coal seam was identified, with 97 km2 classified as Type Ⅰ and 110 km2 as Type Ⅱ.https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025010017deep coalbed methaneenrichment and high yieldmain controlling factorsbenxi formationordos basin |
| spellingShingle | Xiaojiao GUO Lei WANG Xianzhou YAO Xu LI Linke ZHANG Xiaoshuang WANG Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin Shiyou shiyan dizhi deep coalbed methane enrichment and high yield main controlling factors benxi formation ordos basin |
| title | Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin |
| title_full | Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin |
| title_fullStr | Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin |
| title_full_unstemmed | Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin |
| title_short | Geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment: a case study of the M area in the eastern Ordos Basin |
| title_sort | geological characteristics of deep coal rock and main geological factors controlling coalbed methane enrichment a case study of the m area in the eastern ordos basin |
| topic | deep coalbed methane enrichment and high yield main controlling factors benxi formation ordos basin |
| url | https://www.sysydz.net/cn/article/doi/10.11781/sysydz2025010017 |
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