东濮凹陷中央隆起带北部古近系异常高压与油气成藏的关系

渤海湾盆地东濮凹陷北部地区古近系的膏盐岩地层为异常压力提供了很好的保存条件，同时复杂的断裂又为异常高压的释放提供了通道，其油气成藏的动力学过程较复杂，目前对该区异常高压及其对油气运聚的影响规律仍然认识不清。为此，对东濮凹陷北部地区异常压力与油气成藏的关系开展了研究。根据实测资料，分析了该区古近系地层压力的纵向分布特征，并运用流体包裹体方法恢复了古地层压力，对深部和浅部层系的油气充注动力进行了分析；综合划分了该区的油气运聚成藏模式类型。结果表明：①研究区纵向上发育常压、超压和超高压3种类型，其中文明寨-古云集地区以常压为主，卫城、濮城和桥白地区发育常压和超压，文留地区和文卫濮结合部发育常压、超压和超高压；②深部层系的油气充注系统为高压系统或较高压-高压系统，浅部层系油气主要为幕式充注；③研究区洼陷斜坡带的成藏模式包括侧向运聚成藏和自生自储运聚成藏，构造主体的成藏模式包括盐上垂向幕式运聚成藏、盐间复式运聚成藏和无盐区垂向连续运聚成藏。

Relationship between abnormally high pressure and hydrocarbon accumulation of the Paleogene reservoirs in the northern part of central uplift,Dongpu sag,Bohai Bay Basin

The Paleogene evaporation beds in the northern part of the central uplift in the Dongpu sag, Bohai Bay Basin, provide favorable conditions for the preservation of abnormally high pressure. Meanwhile, the complex faults provide passages for the release of the abnormally high pressure. These two factors make the dynamic process of hydrocarbon accumulation there so complicated that the relationship between the abnormally high pressure and hydrocarbon accumulation is still unclear at present. According to the measured data, we analyzed the vertical distribution of formation pressure in the Paleogene, restored the paleo pressure by using the fluid inclusion method, discussed the hydrocarbon charging dynamics in the deep and shallow sequences, and built models of hydrocarbon migration and accumulation in this area. The following conclusions are drawn. (1) Vertically, there are 3 types of pressure systems in the study area, including normal pressure system, overpressure system and abnormally high pressure system. Wenmingzhai Guyunji areas are dominated by the normal pressure system, Weicheng, Pucheng and Qiaobai areas by normal pressure and overpressure systems, while normal pressure, overpressure and abnormally high pressure systems are developed in the Wenliu area and its contacting area with the Weicheng and Pucheng areas. (2) The hydrocarbon charging system in deep sequences is of high pressure system or relatively high to high pressure systems. In contrast, the hydrocarbon charging system in the shallow sequences is dominated by episodic charging. (3) The hydrocarbon pooling models in the slope zone of the sag include lateral migration & accumulation and indigenous accumulation, while those in the major part of the structure include vertical episodic migration and accumulation in the reservoirs above salt layers, inter salt layer compound migration and accumulation, as well as vertical continuous migration and accumulation in the areas without salt layers.