HIGH PRECISION SYNTHETIC SEISMOGRAM FOR SEQUENCE BOUNDARY CALIBRATION TAKING THE PEARL RIVER MOUTH BASIN AS AN EXAMPLE

The accurate calibration of stratigraphic boundaries and sand bodies, which are critical to fine interpretation of seismic data and reservoir prediction, depends on the precision of the synthetic seismogram. It is found that definite wavelet extracted from logging data is an effective way to enhance the precision of synthetic seismogram if rationale time-depth relation and accurate reflection coefficient are adopted, and the Ricker wavelet is an effective tool to judge the quality of seismic data. The combination of the definite wavelet and Ricker wavelet will provide a way to upgrade the precision of geological boundary calibration. In this paper, taking the Pearl River Mouth Basin of the Northern South China Sea as an example, through correlation of the synthetic seismogram and the acquired data, we evaluated the effectiveness of seismic data. The strong reflection of 1225 ms was not a real reflection of a geological boundary, but a superposition of a deeper strong normal reflection during convolution influenced by the side lobe of definite wavelet. Therefore, it does not represent a sequence boundary. Based on the careful study of reflection features of the sequence, a maximum flooding surface and four 3^rd order sequence boundaries as well as two sets of sand bodies were identified as the markers for stratigraphic correlation, fine structural interpretation and reservoir prediction.