NUMERICAL MODELING OF THE ACCUMULATION-FORMING HISTORY OF THE KONGXI BURIED HILL,BOHAI GULF BASIN

A new numerical modeling system of the accumulation-forming history is established by numerical modeling of the essential elements of accumulation formation in carbonate rocks including source rocks, reservoir rocks, seal rocks, traps, primary migration and preservation,and the Kongxi buried hill tectonic belt in the Huanghua depression of the Bohai Gulf basin is used as an example to illustrate the application of this system. As the modeling results show, hydrocarbons were expelled from the Ordovician source rocks of the Kongxi buried hill tectonic belt in the Indosinian period and primary hydrocarbon accumulation began. The Yanshanian period was a main hydrocarbon generation stage and accumulation formation stage, when hydrocarbons were generated, expelled and accumulated in large quantity. Then primary hydrocarbon generation paused. In the Himalayan period, the tectonic belt was further buried and secondary hydrocarbon generation and tertiary hydrocarbon accumulation began. However, the amount of hydrocarbons generated during the secondary hydrocarbon generation was small. So the exploration for Lower Paleozoic primary oil/gas accumulations in the Huanghua depression should focus on the ancient structures that formed in the Indonesian and Yanshanian periods and were not destroyed by the late-stage tectonic movements.