THE VARYING VELOCITY MAPPING TECHNIQUE:ITS KEY PROBLEMS AND ITS APPLICATION TO WESTERN TAZHONG AREA
JIAO Cun-li1,2, ZHOU Jie2, SHANG Ya-zhen2
1. China University of Geoscinses, Department of Geology for Energy Resources, Beijing 100083, China;
2. Institute of Exploration and Development, Branch Company of Zhongyuan Oilfield, Puyang 457001, China
Varying velocity structural mapping is one of the techniques for solving the low-amplitude structural problem and fulfilling trapping. The calculation precision of the velocity field and the method for depth transform seem to be two key links in varying velocity structural mapping. The adoption of the horizontal anti-shifting technique can make the result of the time shift after stack serve only as a bridge in favor of the interpretation and tracking of the reflection horizon and thus avoid the shift and deviation caused by time shift algorithm itself and the influence of shift error caused by the inaccurate shifting velocity upon the construction of the velocity field and the precision of the structural mapping. The inversion of the stacking velocity is used to work out the interval velocity of each layer step by step, and the 3-D spatial ray tracking figure shifting technique is adopted to make spatial shifting and homing of the nil shifting distance time domain T0 into the depth domain to form the depth structural map.