Shahejie-Shahejie/Guantao/Wumishan and Carboniferous/Permian Coal-Paleozoic Total Petroleum Systems in the Bohaiwan Basin, China (Based on Geologic Studies for the 2000 World Energy Assessment Project of the U.S. Geological Survey).

摘要

This report discusses the geologic framework and petroleum geology used to assess undiscovered petroleum resources in the Bohaiwan basin province for the 2000 World Energy Assessment Project of the U.S. Geological Survey (U.S. Geological Survey World Energy Assessment Team, 2000). The report also refers to several later papers (published between 2001 and 2004) that offer additional perspectives. Two total petroleum systems have been identified in the Bohaiwan basin of northeastern China. The Shahejie-Shahejie/Guantao/Wumishan Total Petroleum System, the major total petroleum system in the basin, involves oil and gas generated from mature pods of lacustrine source rock. In general, the mature pods of source rock are associated with six major rift-controlled subbasins that from northeast to southwest are named as follows: (1) Liaohe, (2) Bozhong, (3) Huanghua, (4) Jiyang, (5) Jizhong, and (6) Linqing/Dongpu. The entire Bozhong subbasin and parts of the Huanghua and Liaohe subbasins are located in Bohai Bay. The term Bohai Bay as used in this report follows the usage of Hu and others (1989) and Hu and Krylov (1996). The primary source rock of the total petroleum system is Member 3 of the Eocene and Oligocene Shahejie Formation, and secondary source rocks are Member 2 of the Paleocene and Eocene Kongdian Formation, Members 4 and 1 of the Shahejie Formation, and Member 3 of the Dongying Formation. The majority of the oil and gas fields in the Bohaiwan basin are closely associated with the six subbasins and their mature source rock pods. The most productive sandstone reservoirs in the Bohaiwan basin are located in the Shahejie Formation (Members 1-4), Oligocene Dongying Formation (largely Members 2 and 3), and Miocene Guantao Formation. Also, the Bohaiwan basin has very productive carbonate reservoirs such as the Middle Proterozoic Wumishan Formation, Cambrian Fujunshan and Mentou Formations, and Ordovician Fengfeng and Majiagou Formations. Locally, Archean crystalline basement rocks are important oil reservoirs. Most oil and gas generated from the Shahejie and Kongdian Formations are trapped in large faulted roll-over anticlines, compaction (drape) anticlines, and tilted fault blocks (buried hills). Subtle traps consist of faulted anticlinal noses that may be associated with facies-change, unconformity, or diagenetic stratigraphic traps.