Diffraction Imaging: Resolving Subtle Seismic Geo-features in the Rembrandt and Vermeer Chalk Oil Fields, Dutch Offshore

We present a case study of PreSDM depth migration and diffraction imaging on two Chalk oil fields, in the Dutch F17 offshore sector.

Diffraction Imaging (DI) is an emerging seismic processing technique which produces high-resolution images of small- and medium-scale subsurface elements by extracting the diffractive component of the total wavefield and focusing the diffraction energy to its subsurface origin. The diffraction image, combined with other seismic attributes, can be used to enhance the interpretation value of seismic images, returning a more reliable and higher resolution definition of subsurface discontinuities, thus reducing the interpretational uncertainty. Mapping seismic data in Local Angle Domain opens a new way in creating high fidelity and high resolution seismic images. Opening-angle gathers are employed to obtain high-quality standard full-wavefield depth images. Dip-angle gathers are deployed for separating the reflective and the diffractive components of the full seismic wavefield, a procedure which is fundamental for DI.

The two oil fields are naturally fractured, which greatly aids and controls the flow of the reservoir fluids. Objective of the Diffraction Imaging is to generate independent seismic attributes expected to provide information about the fracture network of the reservoir that can be used to verify the existing fracture model.