综合静校正技术及其在川东高陡构造区应用效果

Comprehensive Static Correction and Its Application for High-Steep Structure in East Sichuan Basin

不同的静校正技术基于不同的模型假设,适用于不同的地表地质条件。川东高陡构造地区,地震资料处理效果证明,在老地层出露区,微测井约束的层析静校正方法取得了满意的效果;在地表平缓地段,基于EGRM的折射静校正效果最好。只有采用综合静校正技术才能优势互补,解决好一次静校正问题。然后进行初至波多域剩余静校正和反射波剩余静校正。讨论了折射静校正、层析静校正和初至波多域剩余静校正的原理、假设条件、适用范围和误差分析,结合实际资料,处理中利用野外高密度的微测井资料,获得折射静校正的风化层速度;利用折射静校正反演的速度模型和微测井建立的速度模型,建立层析成像初始速度模型;利用直达波、折射波和回折波,进行初至波射线路径追踪、走时计算和大型稀疏矩阵方程的求解。

Different methods of static correction are based on different assumed model and applicable to different LVL geological survey.Seismic data processing has proved that tomographic static correction constrained by minilog data was only fitted to the ancient formation exposed surface,and refraction static correction based on EGRM was in flat area.The comprehensive static correction combined tomographic inversion and refraction is once to resolve static correction,then the residual static correction and reflection residual static correction by multi-domain decomposition is used.In this paper,we discussed the principle,assumed model and deviation of refraction and tomographic static correction and refraction residual static correction.In the seismic data processing,we used the high-density minilog data for high-steep structure to gain average velocity of weathered layer in refraction static correction,then the initial velocity model for tomography is constrained by velocity model obtained from refraction and minilog data.We used the direct wave and refraction and turning wave to do the first arrival time ray path tracing,travel time computation and solution of large sparse matrix equation.Although several methods in tomographic correction forward and inversion existed,the method of shortest path ray tracing forward and SIRT inversion was used in this paper.