A Mass Transport Fairway in Block BS-4, Santos Basin, Deepwater Brazil: Implications for Field Development

Lisa B. Ashabranner, R. Craig Shipp, and Neil B. Stillman
Shell International Exploration and Production Inc, Houston, TX

Conventional 3D seismic data were used to investigate a large mass transport “fairway” in Block BS-4 in the Santos Basin, Deepwater Brazil. The objective of this study is to investigate the seafloor and near-surface area, and identify the issues that may impact future field development. The study area is located near the base of a local steep slope (10o) on the lower continental slope, and is ~1.5 km west of most recent MTD. The surrounding seafloor is characterized by a rugose topography, which is the result of hemipelagic draping (up to 65 m thick) over the chaotic surface of a massive MTD. This MTD measures 20 km in the dip direction (west to east) and 8 km in strike, and is bound to the north by an east-west trending local slope, and appears bounded to the south by a deep-seated fault trend. This massive MTD is confined in a distinct fairway updip, which becomes less confined downdip east of the study area. Deeper investigation within the fairway reveals a complex of imbricate MTDs and a variety of conformable packages with varying dimensions. Upon initial examination these multiple MTDs all seem to occupy the same fairway throughout much of the Tertiary.