逆时偏移技术在ZL地区复杂断裂带的应用

Application of reverse-time migration technology in complex fault zone in ZL area

逆时偏移是一种深度域偏移方法,利用3D标量双程波动方程在时间上的反推来实现。它对地震波进行正演模拟,并将检波器接收到的波场作逆时延拓,利用一定的成像条件实现地下各点的成像。该方法成像精度高,适用于介质横向速度变化大和高陡倾角的构造成像。ZL三维实际资料处理中,先对原始资料进行振幅均衡处理,以消除振幅差异对偏移的影响;采用层析成像技术建立了精确的速度模型。经过逆时偏移处理后,大断层归位准确,断阶带内构造细节刻画清楚,提高了ZL地区复杂断裂带的成像精度。

The reverse - time migration is one of depth migration methods. The method is used to the forward of model- ing of seismic wave, and the wave field received by detector is propagated in reverse time direction. And then the imaging of each underground point can be realized according to a certain imaging condition. The method with high imaging accuracy is suitable for the imaging of structure having large changing in lateral velocity of medium and steep dip angle. Tomography technology was used to build an accurate velocity model in ZL 3 D actual data processing. After reverse - time migration, big faults were migrated to right positions, and the structure in the step - fault zone was described in detail. Therefore, it was enhanced to the imaging accuracy of the complex fault zone in ZL area.