Using Multi-focusing 3D Diffraction Imaging to Predict Fracture Corridors/Swarms in the Bazhenov Formation

Unconventional reservoirs are becoming more and more conventional but successful drilling within these reservoirs reservoirs has a unique set of problems. Most wells are drilled horizontally through the reservoir rock and the fracking technology is applied to generate permeabilty and produce hydrocarbons. The pre-drill knowledge of natural fracture swarms and small offset faults is very important as these geological elements can interfere with the drilling and fracking process and influence the production rate. Seismic resolution from conventional reflection imaging is generally not sufficient to resolve these small scale rock properties. Diffracted waves are events that are produced by the scattering of a wave after it meets a discontinuity such as fracture swarms, small amplitude faults and karsts that cause local sharp changes in the geometrical or lithological characteristics. A method for diffraction imaging that is based on coherent summation of diffracted waves was applied to a 3D data set over an unconventional oil reservoir. An integrated study that includes well information, diffraction energy and seismic attributes showcases the usefulness of diffraction events to predict fracture swarms within the Bazhenov formation, which is a black shale in West Siberia.