Evaluation of Source Rock in Xihu Sag in the East China Sea

Abstract

Xihu Sag is the largest petroliferous sag in China offshore area, which is also the main oil and gas exploration battlefield in the East China Sea shelf basin. Source rock is the main material basis for oil and gas generation, its study has important significance on oil and gas exploration in Xihu Sag. By taking source rock of the Eocene Pinghu Formation and Oligocene Huagang Formation of Pingbei area in Xihu Sag as the research object, static characteristics of source rock in Pingbei Area are evaluated and analyzed in the following three aspects: organic matter abundance, types and maturity. The results show that, based on the organic matter abundance, lower member of Pinghu Formation has a high organic matter abundance, mainly gas, while lower member of Huagang Formation is mainly medium-better source rock, with a common hydrocarbon generating potential. Based on the organic matter types, Huagang Formation and Pinghu Formation are mainly type II and type III kerogen, having a certain hydrocarbon generating potential. While, from the point of view of maturity, lower member of Pinghu Formation is under low mature - mature stage, and the lower part of Huagang Formation mainly under mature to high mature stage. Its hydrocarbon generation peak is basically at present.