渤海湾盆地东濮凹陷濮卫洼陷带复杂岩性油气藏形成条件与成藏规律

渤海湾盆地东濮凹陷濮卫洼陷带岩性油气藏形成条件较为复杂。洼陷自身广泛分布的成熟烃源岩是油气成藏丰富的物质基础;物源多、沉积体系类型多、岩性变化快的沉积特点,控制了岩性圈闭的发育分布;多套厚层盐岩的发育、相变,形成了良好的油气遮挡层及盖层,是洼陷带岩性油气藏多层系发育,呈现高压、高充注特点的主要原因;频繁间互发育的非常规储层,多期次油气成藏等地质因素的存在,则使岩性油气藏成藏更为复杂。针对该区发育的砂岩上倾尖灭型圈闭油气藏、砂岩尖灭与断层配置的构造-岩性圈闭油气藏、上倾物性遮挡型圈闭油气藏、透镜状岩性圈闭油气藏等4种主要类型岩性油气藏,通过深入研究生烃层系、岩性相变、非常规储层发育、断裂活动等成藏主控因素,明确成藏规律,对该区下步勘探有重要意义。 

Complex lithologic reservoir formation condition and laws in Puwei Sub-Depression, Dongpu Sag, Bohai Bay Basin

Lithologic reservoirs are formed in complicated conditions in the Puwei sub-Depression, the Dongpu Sag, the Bohai Bay Basin. Wide spread mature source rocks are prolific material basis for reservoir formation. Multiple sources, various sedimentary system types and rapid changes of lithology control distribution and development of lithologic traps. Thick salt development and phase changes form good barrier bed and cap rock for hydrocarbon, which are also the main causes to develop lithologic pools with high pressure and charging. Geological factors such as frequently developed alternated unconventional reservoirs and hydrocarbon formation in multi-phases have made it more complicated for lithologic reservoirs formation. In this paper, it has been carefully researched 4 types of lithologic reservoirs developed in the area, including sandstone up-dip pinch-out trap reservoir, structural-lithologic trap reservoir (sandstone pinch-out collocated with fault), up-dip petrophysical property sheltered trap reservoir and lenticular lithologic trap reservoir. After deep studies on main factors responsible for hydrocarbon generating beds, lithologic phase changes, unconventional reservoir development, breaking activity and so on, reservoir formation law has been definite, which will play an important role for further exploration of the Dongpu Sag.