Publications

Complex geology setting and strong lateral velocity variations creates the mistacking problem in fault shadow area which happens due to lateral varying velocities across the fault area and the reflectors will have distortion because on one side of the fault the velocities are slow and the other side are fast, therefore the reflectors will not stack properly. The PSDM Vertical Transverse Isotropy (VTI) method is able to solve mistacking because the velocity model which is used in this method will be more accurate. To make an accurate velocity model estimation, it is required a method that can represent the real earth condition. And an anisotropic PSDM method is considered to solved this problem. In this case we use Vertical Transverse Isotropy (VTI) model for Anisotropic analysis because this model is able to explain the anisotropic effect simply on the sediment layer. The data processing is divided into two parts namely isotropic PSDM to flatten near offset gather (angle mute <30 degree) and anisotropic PSDM to flatten far offset gather (angle mute >30 degree). Then some parameter which play an important role to make more accurate velocity estimation are Thomsen’s parameter (delta and epsilon), CIP Pick (RMO), Dip Estimation and Tomography (CIP Diff and Z tomo) and the accuracy of the velocity model estimation is controlled by flatness gather and gamma synthetic. The velocity has a good accuracy with the flatness gather and gamma synthetic as the controlling factors shows less error, after that the final velocity model is used for depth migration process to compare the seismic image before and after doing the method. And for the result, PSDM VTI method shows that the result of the velocity model is closer to the real condition and able to flatten the gather until far offset therefore the mistacking problem can be resolved.