Mineral composition and organic geochemistry of the Lower Cretaceous Xiagou Formation source rock from the Qingxi Sag, Jiuquan Basin, Northwest China

Petroleum Science

Ling-Zhi Hu¹  Zhi-Ming Yang¹  Guo-Fu Ma¹  Tao Li¹  Jian-Guo Wang¹  Jun Yang¹  Guo Chen²  Gang Gao²  Wei-Wei Zhang² 

[1] Research Institute of Exploration and Development, Yumen Oilfield Company, CNPC;State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum;

关键词: Mineral composition;    Geochemistry;    Source rock;    Xiagou Formation;    Qingxi Sag;    Jiuquan Basin;   

DOI  :  10.1007/s12182-017-0213-y

来源: DOAJ

【 摘 要 】

Abstract The Lower Cretaceous Xiagou Formation contains the major source rocks for the crude oils discovered in the Qingxi Sag and the South Uplift in the Jiuquan Basin, northwestern China. The Xiagou Formation source rock was formed in a closed, anoxic, reducing, alkaline lacustrine environment with a high salinity. Its high content of brittle minerals is favorable for the fracturing of reservoirs in source rock formations in the Qingxi Sag. The Xiagou Formation contains a great number of fair to excellent source rocks, and their organic matter (OM) came chiefly from plankton/algae and high plants as well as possibly bacterial organisms. The Xiagou Formation source rocks mainly contain Type II OM and some Type III and Type I OM, with good oil-generating potential. The source rock maturity is mainly in the early-mature and mature stages, and its Ro value corresponding to oil peak is about 0.8%, which is lower than classic oil peak Ro value of 1.0%; therefore, a great deal of hydrocarbon was generated before the classic oil peak Ro = 1.0%. Mature source rock in the Xiagou Formation tends to be distributed in the older members and at a greater depth. There is a better exploration potential of tight oil in the deep Qingxi Sag.

【 授权许可】

Unknown