惠州凹陷文昌组—恩平组油气成藏模式

Hydrpocarbon accumulation patterns of Wenchang and Enping Formation,H uizhou Depression

惠州凹陷古近系文昌组—恩平组是油气田勘探的重要接替层系。通过对其烃源岩条件、圈闭条件和构造活动的研究发现,惠州凹陷文昌组—恩平组在始新世—早渐新世和中中新世晚期至今形成了披覆背斜、逆牵引背斜、断背斜、断鼻、古潜山以及岩性等多种类型的圈闭;在49～18.5Ma文昌组—恩平组生成了大量油气,具备形成早期油气藏的条件;中中新世开始的东沙运动使得文昌组—恩平组早期形成的油气藏发生调整。根据油气成藏主控因素分析,将文昌组—恩平组的成藏模式分为早期成藏—晚期保存型、早期成藏—晚期调整型、早期成藏—晚期补充型和晚期成藏4种成藏模式。

The Paleogene Wengchang and Enping Formation act as important replacing targets for hydrocarbon prospecting in Huizhou Depression. Theresearch of the source rocks,the trap characteristics and the tectonic activities indicated that the trap types of Wengchang and Enping Formation are complicated including drape anticlines,reverse drape anticlines,faulted anticlines,fault nose traps,buried hill and lithologic trapsformed in the Eocene-Early Oligocene and the late Middle Miocene. The source rocks of the Wengchang and Enping Formation generated alarge amount of hydrocarbon during the time of 49 to 18.5Ma,which indicated that Wengchang and Enping Formation could meet the requirement of early accumulation,and the pre-formed accumulations had been regulated by the initiation of Dongsha movement at the Midddle Miocene. Based on the analysis on controlling factors,the accumulation patterns of Huizhou Depression were divided into 4 types:earlyaccumulation and later reservation,early accumulation and later regulation,early accumulation and later supplement and later accumulation.