WANG Weili1,2, LIU Luofu1,2*, JIANG Zhenxue1,2, ZHONG Ningning1,2, WANG Ying1,2, WANG Ping1,2, WU Lin1,2, MENG Jianghui1,2, ZHOU Jieli1,2, and GUO Yongqiang3
(1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Changping, Beijing 102249, China
2. Basin and Reservoir Research Centre, China University of Petroleum, Changping, Beijing 102249, China
3. Petroleum Exploration and Production Research Institute of SINOPEC, Beijing 100083, China
Abstract The Western Depression of the Liaohe Basin is the major exploration area of the Liaohe Oilfield, and its main source rocks consist of the third and fourth members of the Shahejie Formation (Es3 and Es4). These source rocks are widely distributed in the depression, with semi-deep lake and fan delta as the main sedimentary facies, brown oil shale and black gray-dark gray mudstone as the main rocks, and a total thickness of 270–1450 m. The kerogens are mainly of the types I and IIA, and partly of the type IIB and least of the type III. The Ro values range from 0.4%–0.8%, indicating an evolution stage from immature to mature. The maturity of Es4 source rocks is relatively high, reaching the early mature stage, but their distribution and thickness are lower than those of Es3. Besides, according to biomarker analysis, it is thought that the source rocks of Es3 and Es4 are characterized by mixed input, and most of the source rocks were formed in the brackish water-saline and strongly oxygen-free environment. Furthermore, the Qingshui, Niuxintuo and Chenjia sags are believed to possess greater potential for hydrocarbon generation and expulsion, for they are source rocks with a larger thickness, have higher organic carbon contents, belong to better organic matter types and possess higher maturities.
Key words source rock; geochemistry; Shahejie Formation; Western Depression; Liaohe Oilfield
* Corresponding author, E-mail: liulf@cup.edu.cn
CHINESE JOURNAL OF GEOCHEMISTRY Vol. 30, No. 4, 2011, page 405-414
© Science Press and Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg 2011
