Oil & Gas Geology ›› 2022, Vol. 43 ›› Issue (6): 1309-1320.doi: 10.11743/ogg20220603

• Petroleum Geology • Previous Articles    

The control of Paleogene peat swamp destruction and reconstruction on the formation of coal-type source material in the Qiongdongnan Basin

Zengxue Li1,2(), Ying Liu1,2(), Xiaojing Li1,2, Gongcheng Zhang1,2, Rui Sun1,2, Dongdong Wang1,2, Lusheng Yin1,2, Jiamin Liu1,2   

  1. 1.Key Laboratory of Sedimentary Mineralization and Sedimentary Minerals in Shandong Province,Shandong University of Science and Technology,Qingdao,Shandong 266590,China
    2.Beijing Research Center,CNOOC,Beijing 100010,China
  • Received:2022-03-21 Revised:2022-09-22 Online:2022-12-01 Published:2022-11-21
  • Contact: Ying Liu E-mail:lizengxue@126.com;liuying-69@163.com

Abstract:

Coal systems and coal seams have been widely valued as an important type of hydrocarbon source rocks for oil and gas reservoirs. Taking the Qiongdongnan Basin of the South China Sea as an example, this study analyzes the genetic relationship between the destruction and reconstruction of peat swamps and terrigenous marine hydrocarbon source rocks, and summarizes the characteristics of the peat swamp destruction as well as the formation and accumulation of peat substances. It is suggested that storms are one of the main dynamic factors for the formation of different land coal and terrigenous marine hydrocarbon source rocks, and this leads to the proposition of a sedimentation mode for the peat storm in the edge of the South China Sea Basin. The results have shown that an unstable and complex interactive relationship exists between the destruction and reconstruction of peat swamps and the formation, decentralization and aggregation of peat substances. The destruction caused a full or partial decomposition and transportation of the peat substances, while the rebuilding restored the development of peat swamps under the suitable climatic conditions. Storms is behind all these destruction and long-distance transportation of peat substance in the swamps in the Cenozoic basins, South China Sea. With storms violently invading and disturbing the coastal peat swamps, large amount of peat clasts were rooted up and carried away by seawater, transported along with storm gravity flow and turbidity flow, and eventually deposited within source rocks as terrigenous marine organic matter.

Key words: peat swamp destruction, coal-system source-sink system, storm, near-source deposition, terrigenous marine hydrocarbon source rocks, Qiongdongnan Basin

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