Acquisition of 2D walkaway VSP data to provide improved imaging of the Thunder Horse North field, Gulf of Mexico

Abstract

Thunder Horse discovery is part of the greater Thunder Horse complex in the Boarshead basin, which is located in the south‐central portion of the Mississippi Canyon protraction area of the Gulf of Mexico. BP owns 75% working interest and ExxonMobil owns the remaining 25% interest in this field. Seismic imaging in the area is very complicated due to an abundance of salt bodies. Different vintages of seismic data acquired with different acquisition geometries do not provide images that can adequately resolve geological details in many important areas. Resolving structural complexity and stratigraphic details via high quality seismic imaging is critical to the success of development of this field. Acquisition of a two‐dimensional (2D) Vertical Seismic Profile (VSP), also known as a walkaway VSP, was determined to be beneficial in this area. A large, 76‐level walkaway VSP was designed and successfully completed in one of the Thunder Horse North development wells. The VSP image was found to be much superior to available surface seismic data. VSP and surface seismic data were combined to generate an improved image of the reservoir intervals.