Reservoir characteristics and reservoir-forming model of multi-element hydrocarbon supply in Zhanhua sag

Zhanhua sag has the characteristic of multi-element hydrocarbon supply, which leads to the diversity and complexity of reservoir forming. Hydrocarbon accumulation unit of the multi-element hydrocarbon supply was divided by tectonic units combined with oil and gas sources, and dissect the source-reservoir system formation of the dynamic process. The hydrocarbon accumulation model of different accumulation units was studied. Researches show that Zhanhua sag can be divided into three kinds of hydrocarbon accumulation units, including hollow-one, hollow-multiple and multiple hollow-multiple hydrocarbons. Along with the establishment of Dongying Formation, the hydrocarbon of the upper part of the Fourth Member of Shahejie Formation matured; the single-source lithologic reservoir in the inner subsag and the reservoir in the gentle slope belt started to develop, and the source rocks entered into the hydrocarbon expulsion phase in Minghuazhen Formation. The extensively source-mixed reservoir formed on the steep slope and central low uplift. The translocation system coupled with reservoir-seal assemblage controlled the hydrocarbon distribution of different hydrocarbon accumulation units: the oil and gas migrated extensively from structural low to high on the plane; and oil and gas accumulated in favorable traps of the gentle slope belt, steep slope zone, low salient and buried hills. In the profile, the autogenously lithologic reservoir formed in member 4 and 3 of Shahejie Formation, oil and gas distributed in the thick layer fluvial facies reservoir of Guantao Formation to form reservoirs of the drape structure in Neogene. © 2015, University of Petroleum, China. All right reserved.