Oil & Gas Geology ›› 2020, Vol. 41 ›› Issue (4): 784-799.doi: 10.11743/ogg20200412

• Petroleum Geology • Previous Articles     Next Articles

Tectonic-sedimentary evolution of Guangyuan-Liangping paleo-rift in Sichuan Basin

Ping Gao1,2(), Shuangjian Li1, Zhiliang He1,3,*(), Yujin Wo1, Yueqin Han1, Xinchen Li4   

  1. 1. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China
    2. School of Energy Resources, China University of Geology(Beijing), Beijing 100083, China
    3. SINOPEC Science and Technology Department, Beijing 100728, China
    4. College of Geosciences, China University of Petroleum(Beijing), Beijing 102249, China
  • Received:2018-12-12 Online:2020-08-01 Published:2020-08-11
  • Contact: Zhiliang He E-mail:gaoping1212@hotmail.com;hezhiliang@sinopec.com

Abstract:

During the Permian-to-Triassic transition, a NW-SE-trending paleo-rift, also known as Guangyuan-Liangping paleo-rift, was developed in the Guangyuan-Liangping area of northern Sichuan Basin.The paleo-rift is of great significance to the oil and gas exploration and development in the northern and northeastern parts of the Basin and therefore calls for an in-depth study on its tectonic-sedimentary evolution.A systematic collection and study of outcrops and drilling data from both inside and outside of the paleo-rift, combined with analyses of corresponding sedimentary records, including unconformities, sedimentary filling, abrupt log response changes, and sediment geochemistry, as well as seismic profiles, shows that the sediments of the 3rd and 4th members of the Maokou Formation extend into the paleo-rift.The absence of an extensive karstification on top of the Maokou Formation in the paleo-rift suggests that, it was sedimentary facies changes, rather than karst erosion, that caused the thinning of the Maokou Formation in the paleo-uplift.The paleo-rift was initially taking shape during the deposition of the 3rd and 4th members of the Maokou Formation and continued to grow during the Wujiapingian stage.It entered the peak development phase during the Changxingian stage when the extensional rifting and hydrothermal activities intensified and tectonic-sedimentary differentiation escalated.It wasn't until the deposition of the 4th member of the Feixianguan Formation that the paleo-rift was completely filled up.The paleo-rift had strong control over the development of the Middle-to-Upper Permian reservoir rocks around it, including the biodetritus beach facies of the Maokou Formation and the grain beach facies in the Wujiaping Formation.Moreover, signs of hydrocarbon migration and accumulation and residual pores in the Wujiaping Formation indicate that the Formation is promising in terms of further hydrocarbon exploration.

Key words: sedimentary records, hydrothermal activity, Changxing Formation, Wujiaping Formation, Kaijiang-Liangping trough, Permian, Sichuan Basin

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