异常高压与油气充注的耦合性——以东海陆架盆地西湖凹陷花港组和平湖组为例

基于声波时差测井、有机地球化学测试及包裹体测试等资料，对东海陆架盆地西湖凹陷花港组和平湖组异常高压进行了研究。西湖凹陷花港、平湖组异常压力主要起始于花港组下段，并且异常高压段具有"阶梯式"增大的特征，横向上从平湖构造带至西次凹向中央反转构造带及从凹陷的边缘向凹陷的中部，高压顶界面在地质层位上有变老的趋势。由高压流体注入引起的传导型超压在区内目的层发育，并对应着良好的油气储层，说明了异常高压发育与油气充注空间上的一致性。利用盆模软件模拟出剩余地层压力的演化过程，认为中新世（15~7Ma）以及上新世至第四纪（3~0Ma）是剩余地层压力异常的2个关键时期。结合油气充注史研究认为，中-晚中新世和早上新世该区发生了2次油气充注，说明异常高压发育与油气充注时间上的一致性。因此，证明了西湖凹陷花港、平湖组异常高压与油气充注具有良好的时空耦合性。

Coupling of abnormal overpressure and hydrocarbon charging: A case from the Huagang and Pinghu formations of Xihu Sag,East China Sea Shelf Basin

Abnormal overpressure in the Huagang and Pinghu formations of the Xihu Sag, East China Sea Shelf Basin was studied based on sonic logging data, organic geochemistry and fluid inclusion testing. The abnormal pressure mainly originated from the lower Huagang Formation, and featured a "step type" distribution in the Xihu Sag. The top interface of high pressure becomes older from the Pinghu tectonic zone to the central inversion structural belt and from the edge to the center of the sag. Conductive overpressure due to the injection of high pressure fluid developed in the study area, and corresponds to good oil and gas reservoirs, which showed that the development of abnormal pressure and hydrocarbon charging had consistency in space. The evolution process of residual formation pressure was simulated using the basin simulation software, indicating that Miocene (15-7 Ma) and Pliocene to Quaternary (3-0 Ma) were the two key periods of residual formation pressure. Hydrocarbon charging history showed that hydrocarbon charging took place twice in the middle-late Miocene and the early Pliocene, which indicated that the development of abnormal pressure and hydrocarbon charging had consistency in time. Therefore, the abnormal overpressure of the Huagang and Pinghu formations coupled in time and space with hydrocarbon charging.