| The study and application of Pre-stack depth migration(PSDM) have been the focuses in Geophysical Prospecting field of the global Oil and Gas exploration for the past decades. Compared with the theory of Pre-stack time migration(PSTM), the methodology of PSDM is more completed and advanced, that has been taken universally as the effective solution to the imaging of complex structure. Recently, the development of computational science and the improvement of migration method have been promoting the study and application of PSDM gradually. In China, satisfactory imaging outcomes have been achieved in deeper parts of East areas and complex structures of West mountainous and desert regions.In DG Oil Field, study and application concerning PSDM have been set forth and certain imaging problems have been solved, such as the processing projects of QMQ buried hills and WGT buried hills. But for other structural areas, such as the QNQB low slope area, PSDM has not been applied. In this paper, we dealt with QNQB low slope area and studied the application of PSDM.The study is based on a production project of DG Oil Field, and is targeted to solve the remaining problems left by PSTM through the introduction of PSDM, and additionally, to try to meet the new demands needed in Oil exploration. Seismic data analysis was done in this study, and so was the corresponding data processing, to guarantee the quality of the CMP gathers. RMS velocity picking and iterative updates were conducted precisely to provide a reliable velocity for velocity model building. Joint utilization of layer-based iterative model building and Pre-stack Kirchhoff depth migration resulted in a clear imaging profile.Applications of PSDM in DG Oil Field have not gained enough momentum and the study of this paper showed promising results of the techniques in this region. The promotions of PSDM have great potentials in increasing the reserves of DG Oil Field. |
