白云凹陷超压模拟及成藏研究

Simulation of Overpressure and Study of Hydrocarbon Accumulation in Baiyun Sag

南海白云凹陷深水区普遍发育超压,超压对油气运移起到重要作用,且对于海上钻井的安全有着重要影响。通过盆地建模Petromod 2014方法对白云凹陷压力-孔隙度-生烃演化进行恢复,探讨超压成因,建立相应的成藏模式。研究表明:①白云凹陷现阶段压力应主要为生烃超压,生烃与超压分布特征一致。②现今超压中心在白云凹陷东部,最大压力系数可达1.8以上。③白云凹陷以“生烃超压驱动、横向砂体输导、断裂-底辟复合泄压”的成藏模式为主,油气藏大多沿着断层与常-超压界面分布。

Overpressure is commonly developed in the deep water area of the Baiyun Sag in the South China Sea,which plays an important role in the hydrocarbon migration and has a significant impact on the safety of offshore drilling.The evolution of pressure-porosity-hydrocarbon generation of Baiyun Sag was restored using basin modeling software Petromod 2014,the forming causes of the overpressure was discussed,and the corresponding hydrocarbon accumulatoin model was established.It is shown that:(1)At present,the pressure in Baiyun Sag is mainly hydrocarbon generation overpressure,and the distribution characteristics of hydrocarbon generation and overpressure are consistent.(2)The current overpressure center is located in the eastern part of Baiyun Sag,with a maximum pressure coefficient of over 1.8.(3)The main hydrocarbon accumulation mode of Baiyun Sag is"hydrocarbon generation overpressure driven,lateral sand body transport,and composite pressure relief of fault and diapir",and hydrocarbon mostly distributed along faults and ordinary pressure-overpressure interfaces.