Research and Application of Shale Oil Fracture Prediction Method Based on Pre-stack Anisotropy Analysis

The shale oil and gas resources is rich in the terrestrial fractured lake basin in the Jiyang Depression, with fracture development and great potential for exploration and development. The favorable aspects of fractures for shale oil development are that they can effectively increase the production capacity of shale oil reservoirs, while the unfavorable aspects are that they increase the difficulty of drilling and cause frequent well surge and well leakage during drilling, which seriously affects the speed and efficiency of drilling. Therefore, the accurate prediction of fractures has been a major problem in the exploration and development of shale oil in this block. In this paper, on the basis of fine description of fractures, combined with the development characteristics and distribution pattern of shale oil fractures in the study area, the distribution of large and medium-scale fractures is firstly predicted using various post-stack seismic attributes such as high-precision coherence, 3D curvature, ant body tracking and maximum likelihood attributes. Then subazimuth and suboffset distance channel set superposition and seismic attribute difference analysis are carried out for OVT domain data, and pre-stack AVAZ inversion is performed to predict the fracture development and characterize the spatial distribution of fractures by combining with geology and logging. The fracture results predicted by the pre-stack anisotropy analysis are highly reliable through comparison with actual drilling conditions and imaging logging results, providing effective technical support for subsequent shale oil exploration and development.