渤海湾盆地渤中26-6变质岩潜山大油田发现与认识创新

Discovery of BZ26-6 metamorphic rock buried hill oilfield in Bohai bay basin and understanding innovation

渤海湾盆地渤南低凸起西段历经40余年勘探,仅在浅层发现渤中26-2小型油田,潜山长期未能实现勘探突破。针对成山机制及圈闭特征、控储要素和储层预测、油藏分隔与成藏规律这三方面,通过精细构造演化、油藏分隔机制和油气富集规律等研究,取得了新认识。研究认为:①多期次构造演化形成大规模潜山圈闭奠定了渤中26-6潜山勘探的基础;②“构造主控,差异溶蚀”控制研究区潜山优质储层发育,基于微古地貌约束的潜山裂缝-孔隙双重介质储层预测技术可以有效刻画优质储层的分布;③潜山内幕断层糜棱岩化作用有效分隔潜山油藏,太古界潜山是油气勘探有利层系。新认识指导勘探实践,2022年在渤南低凸起西段发现了渤中26-6大型整装油田,实现了渤海海域中位潜山勘探领域性突破,进一步拓宽渤海海域太古界潜山带的勘探空间。

After more than 40 years of exploration in the western section of the Bonan low uplift in the Bohai bay basin,only the small-scale BZ26-2 oilfield was discovered in the shallow layer,and exploration breakthrough in the buried hill has not been achieved yet.Through the researches on structural evolution,reservoir separation mechanisms and oil and gas accumulation law,the following new understandings have been gained in terms of the hill formation mechanisms and trap characteristics,reservoir control factors and reservoir prediction,and reservoir separation and reservoir-forming laws:①The multiple tectonic revolutions lead to the formation of large-scale buried hill traps,laying the foundation for the exploration of BZ26-6 buried hill;②The development of high-quality buried hill reservoirs was controlled by“structural movement and differential dissolution”,and the prediction technology of buried hill fracture-pore dual media reservoirs based on micropaleo geomorphic constraints can effectively characterize the distribution of high-quality reservoirs;③Buried hill reservoirs were effectively separated by mylonitization of buried hill interior faults,and the Archean buried hill is a favorable formation for oil and gas exploration.Guided by new understandings,the large-scale BZ26-6 integrated oil and gas field was discovered in the western section of the Bonan low uplift in 2022,achieving a breakthrough in the field of middle-stand buried hills in the Bohai sea,and further expanding the exploration potential of the Archean buried hill in the Bohai sea area.