Oil & Gas Geology ›› 2022, Vol. 43 ›› Issue (5): 1249-1258.doi: 10.11743/ogg20220519

• Methods and Technologies • Previous Articles     Next Articles

Kinetics of high-quality lacustrine source rocks of Paleogene Wenchang Formation, Huizhou Sag, Pearl River Mouth Basin

Xiangtao Zhang(), Yuling Shi, Jie Liu, Huahua Wen, Xingye Yang   

  1. Shenzhen Branch,CNOOC,Shenzhen,Guangdong 518052,China
  • Received:2022-04-05 Revised:2022-07-19 Online:2022-10-01 Published:2022-09-02

Abstract:

The hydrocarbon yields of high-quality semi-deep lacustrine source rocks in the Wenchang Formation from the southwestern Huizhou Sag, Pearl River Mouth Basin, is simulated by the glass-tube pyrolysis experiment under two heating rates in which the thermal crack of hydrocarbon can be avoided to the maximum degree to establish for the first time the kinetic models of heavy hydrocarbon (C14+) generation and gas (C1-5) thermal degration. The theoretical relationship between the transformation ratio and the geological temperature of semi-deep lacusrine source rocks is reconstructed based on the geological extrapolation. It is suggested that the hydrocarbon generation of source rocks in the Huizhou-26 low exhibits the characteristics of “early oil and late gas”. The rapid generation of heavy hydrocarbon (oil) in the early stage corresponds to a geo-temperature from 95 ℃ to 160 ℃ and an age from 40 Ma to 15 Ma. While the large-scale generation of light hydrocarbons (gas) during the late stage corresponds to a temperature range of 119 ℃ to 205 ℃. The source rocks currently are at the end of its major gas generation stage.

Key words: hydrocarbon generation simulation experiment, hydrocarbon yields, hydrocarbon generation kinetics, Wenchang Formation, Huizhou-26 low, Pearl River Mouth Basin

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