Detecting small scale heterogeneities through the application of MultiFocusing 3D diffraction imaging using pre-existing seismic data

Summary Diffraction imaging has become an attribute that’s being used to map naturally occurring fractures in unconventional reservoirs. However, diffractions are generated whenever the wave encounters an irregularity that’s of detectable size. As such, the diffractivity attribute should not be restricted to fracture detection but should be used to map caves (karst), base and shape of salt features, fault detection and possibly separating leaking faults from un-breached reservoir spaces. The extraction of the diffractive part of the wave-field is challenging due to the small magnitude of the event and the noise in the seismic data. We will present the theory and application of a method for diffraction imaging that uses the MultiFocusing principal, which is based on a coherent summation of the diffracted waves and suppression of the reflective part. We implemented azimuthal diffraction imaging, which extracts the diffractivity along chosen azimuths. These results contain not only information regarding small scale discontinuity but also the direction of these features.