OVT域叠前裂缝预测技术研究应用

以塔里木盆地中古地区全方位高密度地震资料为基础,采用叠前纵波方位各向异性技术开展OVT域裂缝预测研究。OVT域地震数据较常规数据能量更为均衡,信噪比更高,且偏移后保留了方位角和偏移距信息,能快速灵活进行方位角和偏移距分选,避免了常规方法耗时长的弊端,适合进行分方位裂缝预测。通过对该地区奥陶系鹰山组石灰岩储层不同偏移距、不同方位角及不同域的数据体进行试验,优选出100~5500m偏移距和6个方位角的数据来计算纵波相对波阻抗的差异,裂缝方向和密度的预测结果与实钻吻合程度较高,能够为该井区储层缝洞连通性研究、井位部署、水平井井轨迹设计提供重要依据。

Fracture Detection with Prestack Seismic Data in OVT Domain

Based on the full-azimuthal and high-density seismic data in Zhonggu district of Tarim Basin, we detected fracture through the P-wave azimuthal anisotropy with prestack seismic data in Offset Vector Tile (OVT) domain. As compared with conventional data, the seismic data after migration in OVT domain is more balanced and has higher signal-to-noise ratio. And it possesses azimuth and offset information, and is suitable to fast predict fracture avoiding much waste of time. So it is applicable for fracture prediction of different azimuths. We tried to examine different offset range and azimuth as well as alterable seismic domain, and then choose the offset in range of 100m-5500m and 6 azimuths to predict fracture. To analyze the relative impendence inversion of every azimuthal data, we achieved the fracture orientation and fracture density of carbonate reservoirs in Yingshan Formation. The results were largely consistent with the practical drilled well and could guide research of well deployment, connectivity of cave-fracture and design of horizontal wells.