Reflection point sideslip and smear in imaging below dipping anisotropic media

Abstract

A B S T R A C TDipping anisotropic clastic strata are ubiquitous in fold and thrust belts. Geological structures below these strata will be mispositioned laterally and vertically on seismic images if we do not properly correct for seismic anisotropy during migration. The magnitude of this lateral mispositioning of a target structure varies with source-receiver offset, so reflection points will be smeared in the final stacked image. Raytracing demonstrates the lateral-position and smear phenomena when imaging structures below tilted transversely isotropic media. Analysis of the raytracing results predicts the quantity of lateral-position error and reflection-point smear on a seismic image. We created numerical-model seismic data to show reflection-point smear on synthetic seismic images and to evaluate the accuracy of the predictions from raytracing.