Improving Underlying Image by Resolving Velocity Anomaly and Compensating for Seismic Absorption Using Q Pre-Stack Depth Migration: A Case Study of 3d Land Sukowati Indonesia

Abstract

Abstract For discovering new opportunities in the northwest of the Sukowati Field reservoir, that limited by the low-resolution images of the subsurface, especially for the target reservoir. The existence of changes in lateral velocity variations, especially in reverse-fault areas and carbonate reservoirs, necessitates the need for an accurate velocity model with validation of the well data, Q Tomography to compensate for the absorption energy, and the migration algorithm that can image the complex subsurface structure. The final velocity model used the Tilted Transverse Isotropic (TTI) anisotropy, by adding the theta and phi (azimuth) models to the migration algorithm, which increased the focus of events, especially on faults, and reflector dips. The PSDM results are also tied to the well marker, indicating validation of the accuracy of the VMB results. The QPSDM application is used for amplitude attenuation compensation in areas with weak amplitudes, QPSDM can also broaden the frequency spectrum. During the migration process, Beam Migration can handle multi-arrival ray traces, making it suitable for application in complex areas. All of the velocity model building processes, resulting in reasonable lateral and vertical velocities controlled by well data, and validated by understanding the geology along the survey area. The final velocity and anisotropy models follow the geological structure well and match the sonic and checkshot information contained in the well data. Beam Migration results produce a better image of carbonate body and layers under the carbonate, which become the target reservoir. This is reinforced by the results of last two drilled wells, the potential of the clastic reservoir has been proven, opening up development opportunities to the west to pursue structural closure of the Transgressive Wings Carbonate. The limited quality of legacy seismic data to see the distribution of reservoirs and limitations in the interpretation of geological structures in the Sukowati Field can be overcome by QPSDM results that produce a more accurate map of the reservoir depth structure, higher resolution of seismic data, minimize uncertainty, and open up opportunities to seek new prospects in the northwest region.