Abstract This is a case study of a 3-D anisotropic prestack depth migration (APSDM) of data from Block L1.0 of the Dutch sector of the North Sea. Producing gas reservoirs in L10 are typical of the area in that they are contained in horst and tilted fault blocks of the Rotliegend Formation. Imaging these fault blocks is made difficult by a complex overburden greatly influenced by salt tectonics. in particular, the overburden includes chalk characterized by fast velocities and a strong vertical velocity gradient. Prestack depth migration (PSDM) is often used in this ara,but the resulting depth images are considered mac-citrate because anisotropy is ignored. Indeed, these depth images are routinely calibrated to well depths, but this is difficult when wells are highly deviated. By contrast, APSDM allows the use of the depths of formation tops from all wells, including highly deviated wells, to constrain and enhance the velocity model. Therefore, accurate depths can be obtained directly from the APSDM image. APSDM should also provide the true lateral positions of dipping events and fault terminations in addition to better focusing of the image To perform APSDM, the anisotropy parameters for the geology must first be estimated, and this task is the main topic of this article. In this study, the parameters were derived from vertical check-shot data, sonic logs, and surface seismic data.