Specularity Gathers for Diffraction Imaging

Seismic diffraction imaging is recognized as a rapidly emerging technology with great potential to reduce exploration and production risks and increase recovery, for conventional reservoirs as well as unconventional resources such as shale gas. The idea behind diffraction imaging in a pre-stack migration framework is to apply a weight factor inside the migration loops, which attenuates events that satisfy Snell's law of specular reflection, while preserving diffractive events that do not satisfy Snell's law. Conceptually, it can be paraphrased as 'switching off reflectivity during migration'. Here we present an approach, called specularity gathers, to construct the weight factor in a very efficient way, with applications on test models and the Eagle Ford shale play of South Texas. Specularity gather analysis proves to be a very useful tool to calibrate diffraction imaging, enabling the efficient construction of diffraction images and updates based on interpretation input. We expect that further development and deployment in the industry will be key in advancing diffraction imaging technology.