Post Migration Azimuthal Residual Velocity Analysis of 3D Seismic Data from Yibal Huwaisah Field, Sultanate of Oman

Subsurface imaging can best be realized by Prestack time/depth migration PSTM/PSDM which is the most widely used tool. PSTM processing would be highly effective should we have an appropriate migration velocity field that is very crucial since a velocity model that is significantly different from the medium velocity, may result a misleading migrated section. Further, it may be noted that residual velocity/move-out analysis is the basic step in velocity field refinement. Further, migration velocity scan is important to arrive at an accurate velocity that is being used as the input to RMO correction. RMO correction is very obvious in wide azimuth (WAZ) than in narrow azimuth (NAZ). Generally, the effect of azimuth is more obvious in far offset than in near offset. Residual move out is applied on pre-stack migrated gathers as it is necessary in anisotropy model building. Due to anisotropy, there may be a deviation in velocity even if migration with correct velocity on almost flat gathers which may be offset by RMS velocity. Some of these aspects are studied with the 3D seismic data from Yibal Al Huwaisah field, Sultanate of Oman and the results are presented highlighting salient features.