Oil & Gas Geology ›› 2022, Vol. 43 ›› Issue (3): 610-620.doi: 10.11743/ogg20220310

• Petroleum Geology • Previous Articles     Next Articles

Reservoir exploration of the Permian Maokou Formation in the Sichuan Basin and enlightenment obtained

Yu Zhang1(), Qinggu Cao2, Kaiping Luo2(), Longlong Li2, Jinlian Liu1   

  1. 1.Oilfield Exploration and Development Division,SINOPEC,Beijing 100728,China
    2.Wuxi Research Institute of Petroleum Geology,Petroleum Exploration and Production Research Institute,SINOPEC,Wuxi,Jiangsu 214126,China
  • Received:2021-03-15 Revised:2022-03-08 Online:2022-06-01 Published:2022-05-06
  • Contact: Kaiping Luo E-mail:zhangyu688@sinopec.com;luokp.syky@sinopec.com

Abstract:

The Permian Maokou Formation among the first batch of exploration targets is one of the most actively explored formations in the Sichuan Basin. Gas reservoirs in the formation can be classified into five types in terms of reservoir characteristics, that is, reservoirs of fracture type, karst fractured-vuggy type, hydrothermal dolomite type, shoal dolomite type and marl type, and are dominated by lithologic reservoirs. These types of gas reservoirs show diverse characters in different stratigraphic intervals and different plays. The previous exploration results of Maokou Formation and characteristics of different gas reservoirs, demonstrate that favorable sedimentary facies zones such as marginal-platform shoals, intra-platform shoals and deep gentle slopes serve as basic conditions for reservoir development, and pseudocontemporaneous dolomitization, late hydrothermal dolomitization, epigenetic karstification, and tectonic transformations such as folds and faults are the keys to forming high-quality reservoirs therein. It is pointed out that karst fractured-vuggy reservoirs, dolomite reservoirs of shoal facies and marl reservoirs in the first member of Maokou Formation (Mao 1 Member) as controlled by facies (geomorphology), characterized by continuous distribution and high quality, are the main exploration targets in the future. The northeastern and southern-southeastern parts of Sichuan Basin are the most favorable play fairways for the exploration of Maokou Formation. The superposition of various reservoir types and exploration fields is of value to setting up a holistic pattern for exploration.

Key words: gas reservoir type, reservoir, exploration field, play fairway, petroleum exploration, Maokou Formation, Per-mian, Sichuan Basin

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