断块运动与潜山油气藏的形成——以渤海湾盆地为例

FAULT BLOCK MOVEMENT AND FORMATION OF BURIED HILL HYDROCARBON RESERVOIR: TAKING BOHAI BAY BASIN AS AN EXAMPLE

文章从渤海湾盆地断块运动的机理出发,对其潜山油气藏的形成及运聚规律进行了分析研究,认为该盆地的断块可划分为倾斜断块、翘倾断块和陷落断块3种类型。据此可将渤海湾盆地的凹陷或洼陷划分成倾斜断块区、翘倾断块区和陷落断块区等3个区。断块运动不仅形成古潜山构造,而且对其储层、圈闭及油气运聚都产生了积极的影响。油气以垂向运移为主,运距较近,圈闭油气充满度高,断裂带控制油气聚集。陷落断块区虽然埋藏最深,但仍具有较好的油气潜力,提高地震采集及信息处理的技术是未来努力的重要方向。倾斜断块区油气前景较好,翘倾断块区更好,并容易形成较大规模的油气藏,应是未来深部勘探的重点区域。

In order to provide a theoretical basis for exploration and development of the deep oil and gas reserovirs in Bohai Bay basin, this paper studies the formation of the buried hill hydrocarbon reservoirs and the pattern of hydrocarbon migration and accumulation, beginning with the mechanism of fault block movement in Bohai Bay basin. The fault blocks in Bohai Bay basin can be divided into three types, including inclined fault block, tilted fault block and depressed fault block. Accordingly, the sag/sub-sags in Bohai Bay basin can be divided into fault block zone, tilted fault block zone and depressed fault block zone. The fault block movements not only have created the buried hill structures, but also have positively influenced the reservoirs, traps and migration and accumulation of hydrocarbons. The hydrocarbons are dominated by vertical migration in relatively short distance, the coefficient of fullness of hydrocarbons is large in traps, and the faulted zone controls the accumulation of hydrocarbons. The depressed fault block zone still has relatively large oil and gas potentials though its buried depth is the largest and the future exploration efforts should be focused on improvement of seismic acquisition and processing in this zone. The exploration potentials are relatively high in the inclined fault block zone and are even higher in the tilted fault block zone, where favorable conditions existed for the formation of large-scale oil and gas reservoirs, thus the tilted fault block zone should be taken as the focus for exploration of deep reservoirs in the future.