Summary
Detection of faults system and fracture zones are of great importance in reservoir characterization. Strike-slip faults and associated fractures is one kind of very important geological setting for oil and gas reservoirs. However, it is extremely difficult to reliably and accurately detect the strike-slip faults and associated fractures based on the seismic data compared with conventional faults system because there are very small or fewer faults throw in the strike-slip faults system. Recently, the breakthrough are coming for detection of strike-slip faults and associated fractures with the more and more acquisition of high density and wide azimuth seismic data in China. Based on the wide azimuth seismic data, we can use multi-azimuth seismic attributes to detect and interpret different directional faults and associated fractures, and finally to combine the directional faults to identify and interpret the strike-slip faults system and associated fracture zones based on some geological constrains, such as Sylvester shear mode of strike-slip system and faults associated fracture theory, etc. Based on one of our studies, we proposed an approach of detecting strike-slip faults and fracture zones based on wide azimuth seismic data by using azimuth oriented filtering (or structure oriented filtering) and some multi-azimuth seismic attributes, such as multi-scale edge-detection, direction-weighted coherence analysis and volumetric curvature, etc. The approach proposed in this paper has been applied to one of reservoir characterization projects in western China, and the results have showed the reliability and accuracy of the proposed approach in dealing with the detection of very complex strike-slip faults system and associated fractures in the area.
Introduction
Strike-slip faults are one very special kind of faults system with very small or fewer faults throw vertically and complex accompany faults system, and with the potential for oil and gas reservoirs (G.P. Jobidon, 1970; Sylvester, 1988). So the conventional seismic profiling methods can not give reliable identification and interpretation of strikeslip faults system and associated fracture zones. Recently, wide azimuth seismic data has been widely used for fractures detection and some complex faults system identification (Gray, F. D., and Head, K. J., 2000; Mu Luo and Brian J. Evans, 2003) with the advantages of rich azimuthal anisotropy information in the data which has been applied to both pre stack and post stack domain.
