Application of multi-azimuth AVO technique in fractural detection
Liu Peng-bo1, Pu Ren-hai1, Pan Ren-fang2, Zhu Zheng-ping3
1. Department of Geology, National Key Lab of Continental Dynamics, Northwest University, Xi'an City, Shanxi Province, 710069, China;
2. College of Geoscience, Yangtze University, Jingzhou City, Hubei Province, 434023, China;
3. Landmark Graphics International Inc.,Beijing City, 100004, China
Abstract：In seismic data of 3-D CRP gather, the amplitude changes not only with variation of incident angles, but also with variation of the azimuths. The later has corresponding relationship to the anisotropy of strata, especially when the fracture with some azimuth is appeared in the strata. The AVO attribute parameters may show distinctive difference on CRP gathers between near-parallel and near-vertical to the fractural direction, the size and planar distribution of which just reflect the developing level and distribution of fracture. On the basis of prestack time migration for 3-D P-wave gathers data, the paper carried out analysis of AVO anomalous attributes parameters on gathers data sorting from inline and crossline directions respectively, then, analyzed the difference of attributes parameters between these two directions, and finally applied the size and distribution of the difference to detect the development of fracture. The results showed the development of fracture predicted by the method and reflected by drill core and imaging logging is coincidence, and fracture predicted by the method has some relationship with the distribution of fracture pointed by coherent body.
