Division of hydrocarbon accumulation assemblage and prediction of favorable accumulation assemblage in ZhuⅠDepression

In order to find the further exploration target and reduce the exploration risk in the eastern Pearl River Mouth Basin, this paper analyzed hydrocarbon accumulation assemblage and hydrocarbon charging conditions to study the dominant migration and accumulation direction of oil and gas in different hydrocarbon accumulation assemblages in the ZhuⅠDepression. According to the study, the lithologic combination of the regional caprock and fault activity intensity control the distribution and enrichment of oil and gas. Oil and gas mainly accumulate in strata above the Enping Formation, when the sand/formation ratio of the direct caprock on the source, is greater than 50% and the fault displacement is greater than 140 m; The main hydrocarbon accumulation assemblage and accumulation zones are usually located above the source-kitchen in sags with long-term fault activities and superimposed activities of multi-episodic fault where oil and gas is mainly migrated vertically; for the sags where the faults are only active in the early stage and the degree of fault superimposition in different periods is low, the hydrocarbon accumulation assemblage in source and near source is more favorable, the favorable accumulation zones are usually located at the edge of depressions and uplifted areas in Zhuhai-Yuehai Formation accumulation assemblage where is far away from the source rock.