渤海海域油气分布特征及主控因素

渤海海域已探明油气储量中,构造油气藏所占比例最高(66.8%),其次是复合油气藏(25.9%).占油气田总数34%的大中型油气田,探明油气储量却占总储量的84.4%.低凸起、凹中隆和凸起构造带油气探明储量最多,分别占总探明储量的45.3%,24.9%和22.0%.纵向上,61.0%的已探明石油储量和55.0%的已探明天然气储量集中分布于新近系地层中.93.2%的已探明石油储量和85.0%的已探明天然气储量分布在小于3000m的浅-中层储层内.渤海海域油气分布是海域烃源岩、沉积体系、构造及断裂体系发育与演化等一系列地质过程相互作用的结果.油气围绕富生烃凹陷近距离运移聚集;有利沉积相带、优质岩相及良好的物性决定了渤海海域发育优质储层;郯庐断裂及次级断裂控制了富生烃凹陷、圈闭及输导体系的形成与发育.

Hydrocarbon distribution features and main controlling factors in the Bohai Sea waters

Among the proved reserves in Bohai Sea waters,those from structural hydrocarbon pools account for the most,taking up 66.8% of the total,while complex pools contain second largest reserves (25.9%).The number of the large/medium-sized fields only accounts for 34% of the total,while their proven reserves account for 84.4% of the total.Proven reserves are most numerous in structures of low salient,swell in sag,and salient,accounting for 45.3%,24.9% and 22.0% respectively.Vertically,about 61.0% of the proven oil reserves and 55.0% of the proven gas reserves are distributed in the Neogene.About 93.2% of the proven oil reserves and 85.0% of the proven gas reserves are distributed in the shallow to medium reservoirs with burial depth less than 3 000 m.The hydrocarbon distribution in Bohai Sea waters is the result of a series of geological processes,involving hydrocarbon source rock,depositional systems,structures,as well as fault systems.The hydrocarbons migrated in short distance and accumulated around the hydrocarbon kitchens.Factors such as favorable sedimentary facies belts,high-quality lithofacies,and favorable physical properties played important roles in the development of high-quality reserviors in Bohai Sea waters.The Tanlu fault and its induced faults controlled the formation and development of hydrocarbon kitchens,traps and carrier systems in the study area.