Francis Rollins

3D Salt-flank Imaging With Transmitted Arrival VSP Data

A 3D wave-equation migration algorithm has been developed to image salt flanks with transmitted arrival VSP data. A precise knowledge of the salt flank location is often essential for accurate resource estimates and optimal well planning. The traditional salt-proximity survey provides a poorly constrained line in 3D space. In this abstract we develop a method to image the full salt surface by utilizing long-offset walk-away and 3D VSP datasets that are frequently acquired for imaging purposes. The method has been successfully demonstrated on a real data example.

Mississippi Canyon high resolution reprocessing: applications for shallow drilling hazard and geologic evaluation

Summary A joint contractor-company project was undertaken to evaluate the practicality and utility of shallow high resolution reprocessing of large deepwater exploration 3D seismic surveys. An approximately 575 square mile subset of a regional Mississippi Canyon survey in the deepwater Gulf of Mexico was selected and the upper six seconds of the dataset was reprocessed with focus on maximizing resolution in the shallow, usually suprasalt, sediment column. The intent was to not create new technology, but to utilize advances in computing power to cost effectively create a large regional 3D survey suitable for enhancing the ability to interpret and characterize the deepwater shallow overburden. The result was the creation of a high quality 3D dataset used extensively for shallow hazard analysis, shallow water flow unit characterization, and regional geologic interpretation.

Wide Azimuth Anisotropic Imaging At Tubular Bells Field In the Gulf of Mexico

BP, with co-owners Chevron and Hess, acquired a Wide Azimuth Towed Streamer (WATS) survey over the Tubular Bells field in the deepwater Gulf of Mexico to address challenges of imaging subsalt reservoirs. Finite-difference modeling shows that we need to incorporate anisotropy to properly image subsalt reservoirs at Tubular Bells. We present the processing and model building work flow; in particular, how we use Reverse Time Migration (RTM) to image steep dips that results in a better velocity model. The final migrated dataset provides a significant improvement in image quality over the conventional narrow azimuth (NATS) data, and is being used to reinterpret the area.