ADVANCED APPROACH TOWARD UNDERSTANDING GEOLOGICALLY COMPLEX AREA USING MDRS (MULTI-DIP CRS): A CASE STUDY

摘要

MDRS (Multi-dip CRS) is an alternative stacking method for complex structures based on the common-reflection-surface (CRS) technology. The method offers not only an improved signal to noise ratio of data but also a higher fidelity of wavefield representation by treating conflicting dips. In this method, a reflection event can be enhanced by a CRS operator that stacks seismic traces over an offset-midpoint surface describing a reflection wavefield from a dipping curved boundary. MDRS handles several CRS operators at each zero-offset point so that conflicting dips can be described. MDRS also provides objectively-analyzed velocity information, which can be a useful attribute in understanding velocity structure. A CRS operator is described by the three kinematic wavefield parameters (a, K_N, and K_(NIP)) and they are automatically analyzed from data at every zero-off"set sample. Since CRS parameters can be converted to RMS velocity, a high-density RMS velocity field is obtained without much humanintervention. MDRS is beneficial especially in geologically complex areas having the following problems: signals are weak, wavefield is complex, and velocity estimation by conventional method is difficult. We have successfully applied the method to such kinds of data sets and got improved seismic data quality with better velocity estimation. In this paper, we describe the use of the MDRS method and show its benefit in understanding geologically complex area through a case study.