China Petroleum Exploration ›› 2025, Vol. 30 ›› Issue (5): 38-54.DOI: 10.3969/j.issn.1672-7703.2025.05.004

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Reservoir characteristics, diagenesis and main controlling factors for coal measure tight sandstone gas in Shenfu block, Ordos Basin

Liu Yancheng1,Mei Xiaohan1,ian Jijun2,3,Liu Boyuan1,Yuan Yin2,3,Wang Daxing2,3   

  1. 1 China United Coalbed Methane Co., Ltd.; 2 Key Laboratory of Tectonics and Petroleum Resources, Ministry of Education, China University of Geosciences; 3 School of Earth Resources, China University of Geosciences (Wuhan)
  • Online:2025-09-15 Published:2025-09-14

Abstract: The tight gas discoveries have been made in Benxi Formation and Taiyuan Formation in Shenfu block, Ordos Basin. A better understanding of reservoir characteristics and the main controlling factors is of great significance for the high-efficiency development of coal measure tight sandstone gas. Based on petrology, cast thin section, scanning electron microscopic imaging and high pressure mercury injection test methods, the rock types, reservoir physical properties and diagenesis of tight sandstone reservoirs in Taiyuan Formation–Benxi Formation in Shenfu block have been analyzed, and the main controlling factors affecting reservoir development have been discussed. The study results show that the reservoir lithology of Benxi Formation and Taiyuan Formation is mainly composed of quartz sandstone, lithic quartz sandstone and feldspar lithic sandstone. The main reservoir space types include intragranular dissolution pores, intergranular dissolution pores,intercrystal pores, matrix dissolution pores and micro fractures, followed by primary residual pores, and the throats are mostly fine–medium throats. Compaction and partial cementation had destructive effects on sandstone reservoirs, while dissolution, tectonic activities and chlorite film had constructive effects. The development of sandstone reservoirs in Taiyuan Formation–Benxi Formation was significantly controlled by sedimentary microfacies. The delta underwater distributary channel and tidal channel microfacies were conducive to the development of high-quality reservoirs, and the physical properties of tight sandstone reservoirs were further improved by lithic dissolution, micro-fractures generated by tectonic activities and chlorite films. The high-quality reservoir sand bodies are mainly distributed in the southeastern Xiejiapu and the southern Langanpu areas with underwater distributary channels and tidal channels developed.

Key words: Ordos Basin, Shenfu block, Taiyuan Formation–Benxi Formation, tight gas, reservoir characteristics, diagenesis, main control factor

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