Precambrian Oil and Gas in China

Hao Shisheng, Guangdi Liu

Abundant Precambrian oil and gas occurring mainly in two large basins, Sichuan basin in southwestern China and Bohai Bay basin in northern China, account for a considerable portion of the reserves and production in China. The Precambrian producing formations are all carbonates. Weiyuan gas field in Sichuan basin is one of the large gas fields in China. Its gas is produced primarily from the dolomite of the Dengying Formation (Sinian System) and was generated chiefly in the algal dolomite of the same system. However, a deeper origin for the gas cannot be ruled out. Renqiu oil field in Bohai Bay basin, a buried-hill oil field, is also one of the largest oil fields in China. The oil is produced primarily from the dolomite of the Wumishan Formation of the middle-upper Protero oic and was generated chiefly in the Oligocene Shahejie Formation. It is also possible that the oil was partly sourced by middle-upper Proterozoic rocks. In addition, many oil and gas shows have been found in the middle-upper Proterozoic of the Yanshan foldbelt at the northern margin of the Bohai Bay basin. According to an organic geochemical study, the middle-upper Proterozoic in the area has a good potential for hydrocarbon generation, and formation conditions for indigenous hydrocarbon accumulations should exist in the Bohai Bay basin and nearby Yanshan foldbelt.

From the analyses of hydrocarbon generation, reservoir, cap rock, trapping, and preservation, the presentation systematically describes the petroleum geological features and hydrocarbon prospects of the Precambrian in China.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.