双城地区中浅层压力系统对油气运聚的控制

Control of Middle-shallow Pressure System on Hydrocarbon Migration in Shuangcheng Area

双城地区受构造条件、沉降速率、断裂活动和剥蚀程度等因素的影响,不同层位具有不同的压力特征,受断层的阻隔作用同一层位压力分布也是不均匀的,异常地层压力在研究区内普遍存在,既有异常高压同时又存在异常低压,由于欠压实作用青山口组具有异常高压,形成欠压实封闭,促使油气向下伏地层泉头组运移聚集,由于地层剥蚀卸载后的弹性回返(反弹)和轻烃的扩散作用等因素的影响在扶扬油层内普遍存在异常低压,且压力分布是不均衡的,低压区是油气聚集有利部位。研究表明双城地区压力系统对油气运聚具有明显的控制作用。

Being affected by structural condition,subsidence rate,fracturing movement and denudation,different formation has different pressure characteristics in Shuangcheng area.Because of the barrier effect of faults,pressure distribution in a same formation is not uniform.Abnormal pressure areas exist widely in the studied area.There is not only abnormal high pressure but also abnormal low pressure.Qingshankou Member has abnormal high pressure caused by under-compaction effect,and forms under-compacted sealing,making hydrocarbon migrate and accumulate toward underlying Quantou Member.Being affected by the elastic bouncing after formation denudation unloading and the diffusion of light hydrocarbon,abnormal low pressure exists widely in Fuyang reservoirs with nonuniform distribution.Low pressure areas are favorable for hydrocarbon accumulation.The study shows that pressure system of Shuangcheng area has apparent controlling effect on hydrocarbon migration and accumulation.