Seismic Imaging in Complex Geological Area Using Pre-Stack Depth Migration (PSDM) and Tomography Method

Abstract

Pre-Stack Depth Migration (PSDM) method is required for seismic imaging in the area with complex geological structures such as fault, anticline, or syncline. Result of the PSDM depends on the interval velocity model as its input. A valid interval velocity model can yield appropriate seismic section and vice versa. One way to get an accurate interval velocity model is tomography method. This method can refine interval velocity model until it has minimum error. In this research, it’s used 2 kinds of tomography method, i.e. horizon based tomography and grid based tomography. Horizon based tomography considers the depth model in interval velocity refinement process, while grid based tomography doesn’t. Tomography is done till 6th iteration where the result of 6th iteration show the best quality of seismic section. The results show that the best quality section is PSDM using horizon based tomography. It has more geological sense than the PSDM section using grid based tomography and PSDM without tomography. Furthermore, PSDM using horizon based tomography is capable to correct pull-up effect with better continuity.