China Petroleum Exploration ›› 2021, Vol. 26 ›› Issue (3): 79-87.DOI: 10.3969/j.issn.1672-7703.2021.03.007

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Research on gas accumulation characteristics of aluminiferous rock series of Taiyuan Formation in Well Ninggu 3 and its geological significance, Ordos Basin

Meng Weigong, Li Xiaoguang, Wu Bingwei, Gong Zhenchao, Dong Desheng, Liu Yuanyuan, Xian Xiuming   

  1. PetroChina Liaohe Oilfield Company
  • Online:2021-05-14 Published:2021-05-15

Abstract: Major breakthrough has been made in natural gas exploration of aluminiferous rock series of Permian Taiyuan Formation in Well Ninggu 3 in the southwestern Yishan Slope, which alters the traditional understanding that aluminiferous rock series can’t form effective reservoir. In this paper, research on reservoir quality, gas-bearing properties and gas accumulation characteristics has been carried out to further evaluate the potential of aluminiferous rock series and search for large-scale discovery. By using the regional geology, drilling, logging and testing data, gas accumulation conditions and pattern of aluminiferous rock series of Taiyuan Formation in Well Ninggu 3 has been studied in detail, which shows that (1) aluminiferous rock series consist of thin interbedding of bauxite, bauxitic mudstone, sandstone and tuff, and porosity-fractured reservoir is developed controlled by sedimentation and tectonism with main reservoir space of residual intergranular pore, intergranular dissolution pore, intercrystalline pore and microfracture; (2) The aluminiferous rock series is paragenetic or directly contacted with Permian coal measure source rocks, forming self-generation and self-storage type source rock-reservoir assemblage;(3) Influenced by the Indosinian-Yanshanian tectonic movement, faults and fractures are well developed, which effectively improve the hydrocarbon transport capacity. In a word, the coupling relation between “source rock, reservoir and fracture” is the key for gas accumulation. The discovery of Well Ninggu 3 expands gas exploration field in the Ordos Basin, and shows great potential and broad prospect of aluminiferous rock series.

Key words: Ordos Basin, Taiyuan Formation, aluminiferous rock series, porosity-fractured reservoir, self-generation and self-storage type assemblage, new field

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