缝洞储层地震波场数值模拟

Seismic wavefield numerical simulation of fractured reservoir

为了揭示缝洞储层的地震波场特征 ,首先推导出了允许介质速度有纵横向变化 ,对地层倾角无限制 ,保振幅 ,并可以避免层间多次波产生的变参考慢度Rytov近似Fourier波场延拓算子 ,然后用该算子对根据某地区奥陶系储层溶蚀缝洞的地质特征所设计的四个缝洞模型进行正演和偏移并分析其波场特征。缝洞储层模型数值模拟的结果揭示了在不同情况下 ,单个裂缝、溶洞、缝洞带的宽度和密度的地震波场特征 ,得到了一些有益的结论和认识。

To reveal the wavefield characters of fracture reservoir, a Fourier wavefield continuation operator of variational reference slowness Rytov approximation was derived. This operator can preserve amplitude and suppress inter bed multiples without restrictions on horizontal and vertical changes of medium velocity and layer dip angle. The operator was then used in the forward modeling and migration on the four fracture cave models built based on geologic features of the corroded fractures and caves in an Ordovician reservoir and the resulting wavefield was analyzed. Some conclusions were drawn from numerical simulation on single fracture,cave,and fracture cave zone of different width and density.