China Petroleum Exploration ›› 2019, Vol. 24 ›› Issue (1): 95-104.DOI: 10.3969/j.issn.1672-7703.2019.01.010

• PETROLEUM GEOLOGY • Previous Articles     Next Articles

Sedimentary system types and distribution of the 3rd upper sub-member of Silurian Kepingtag Formation in Tazhong area, Tarim Basin

Zeng Qinglu1, Wang Libao1, Wang Chaofeng1, Wang Junpeng1, Wang Ping2, Zhang Xianlong1, Zhao Jilong1   

  1. 1 PetroChina Hangzhou Research Institute of Geology;
    2 Research Institute of Exploration and Development, PetroChina Tarim Oilfield Company
  • Received:2018-05-20 Revised:2018-09-21 Online:2019-01-15 Published:2019-01-02
  • Supported by:
     

Abstract: As the important marine clastic exploration target in Tazhong area, Tarim Basin, the 3rd upper sub-member of the Silurian Kepingtag Formation was analyzed using core, logging, seismic and experimental data, and the types and distribution of the sedimentary systems were systematically researched according to the paleo-geomorphology, paleosalinity and hydrodynamic force before deposition. The results show that the Silurian paleo-geomorphology gradually increases from north to south, with multiple narrow and long low sags and underwater bulges. The depositional systems of tidal flat, estuary and tidal delta are developed and controlled by the palaeo-geomorphology in the background of transgression, and the differences in the types and energy of primary activating water forces developed different types of sand and sedimentary formations. In the sedimentary system of the tidal flat, primary types of sand bodies are subtidal channels and intertidal flats. The former show complete three layers and are vertical to the coast in banded distribution. Channels and tidal bars are common in the estuary system. The sandstone has thin mudstone, and the axis of the sandstone extends far and parallel to the axis of the estuary. Underwater distributary channels are developed with silica, flint gravel and large erosion surfaces in the tidal delta system. Finally, the depositional model composed of tidal flat, estuary and delta was established and the distribution of favorable reservoirs was predicted in Tazhong area.

 

Key words: Tazhong area, Silurian, tidal action, sedimentary system, sandstone distribution

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