Source rocks and origin of oil and gas in the northern Baiyun Depression of Pearl River Mouth Basin
Fu Ning1 Mi Lijun2,3 Zhang Gongcheng1(1.CNOOC Research Center, Beijing100027, China; 2.China University of Petroleum, Beijing 102249, China; 3. Exploration Department of CNOOC China Ltd., Beijing 100027, China)
The most important source rocks in Baiyun Depression of Pearl River Mouth Basin are the type Ⅰ─Ⅱ1 lacustrine sediment of Eocene Wenchang Formation, and the type Ⅱ─Ⅲ terrestrial shale and coal-bearing strata of Oilgocene Enping Formation. The oil-gas source correlation suggested that oil and gas in the north slope of Baiyun Depression was derived from the Oilgocene type Ⅱ2 terrestrial sediment. The pool filling process showed that natural gas was accumulated from Oilgocene source rocks in the stage of high vitrinite reflectance value from 1.2% to 1.8%. The abundance of source rocks in Wengchang Formation was evaluated as the best. The features of oil-gas generation and accumulation of Wenchang Formation in early period were obvious. The mature source rocks are in the south areas of Baiyun Depression, which is the best region for oil exploration, and the northern slope of Baiyun Depression is the best region for gas exploration.