Tomography with Geological Constraints - An Alternative Solution for Resolving of Carbonates

Carbonates are often present in close proximity to salt in the sedimentary basins around the world. They could be highly heterogeneous and in addition are often interspersed with lower-velocity sediments. The occurrence of high-velocity contrast layering in some portion of the lithology section could pose a problem for grid tomography and may result in insufficient resolution and poor delineation of the layer boundaries, unless many iterations of high-resolution tomography are run. We present a method for successful delineation of carbonate layers by introducing implicit and explicit geological constraints during the global common image point (CIP) tomography updates. The use of geological constraints in the CIP tomography yields high-resolution models over large areas of significant complexity with a reduced number of iterations. In addition, it eliminates the need to consider separate geobodies and multilayer representation of the medium. We show examples of successful application of this method to data sets with variable acquisition geometries from the Gulf of Mexico and offshore West Africa.