全波形反演技术在深海地震成像中的研究及应用

Research and Application of Full Waveform Inversion of The Deep Sea Seismic Imaging

深水勘探速度建模和成像精度受到崎岖海底,海水速度,深层复杂构造,复杂绕射多次波等问题影响。全波形反演作为利用波形匹配计算模型扰动的反演方法,能够获取高分辨率的模型参数,提高偏移成像精度并降低勘探风险。针对深水资料一般只能采集到反射波资料,采用相关目标函数计算了反射波速度梯度;针对变化的海水速度,利用海水反射的波形反演计算深水海水速度;针对鬼波和多次波,采用鬼波压制流程拓宽频带,压制子波波旁瓣,采用多次波压制流程简化波场,提高反演稳定性。最后给出针对深水碳酸盐岩工区和水合物工区的测试案例。

The velocity modeling and imaging accuracy of deep water seismic exploration is affected by problems such as rugged sea bottom,seawater velocity,deep complex structure,and complex diffraction multiples.Full waveform inversion as an inversion method using waveform matching calculation model perturbation,capable of inversion high resolution model parameter,It can improve the Migration and imaging precision and reduce the exploration risk.Only reflected wave data can be record by deep water data,and the reflected wave velocity gradient is calculated by using the cross-correlation objective function;Calculate the velocity of deep water by FWI and sea reflection wave;Using deghost broden seismic frequency band,compresses wavelet,suppresses multiple and simplified wave field,and improves inversion stability.Finally,giving the FWI cases of deepwater carbonate rock and gas hydrate.