Exploration of Offshore Togo (Benin Embayment); a New West African Play Type

By

Mark Sturgess¹, Dick Murdock¹

(1) Togo Hunt Oil Company, Dallas, TX

 Togo Hunt Oil Company’s contract area offshore Togo covers approximately three thousand two hundred square kilometers (3200 km2), ranging from the shelf to water depths greater than three thousand (3000) meters. A two thousand seven hundred and seven (2707) square kilometer 3D seismic survey exists entirely within the contract area, acquired by PGS in late 1998. This survey revealed the presence of major structural anomalies and thicker than normal Tertiary sediments.

Offshore Togo thus represents an area of untested plays on the transform margin of equatorial West Africa. The play of highest interest consists of Late Cretaceous shelf / slope / submarine fan sandstone reservoirs, sourced by underlying mature, source rocks deposited during the Late Cenomanian to Early Turonian worldwide oceanic anoxic event. These reservoir targets are associated with transpressional antiforms, creating migration focus and large trapping geometries. The influx of thick Late Cretaceous and Tertiary clastics associated with the paleo and present day Volta River drainage ensures adequate burial of the source rock to peak oil generation levels, and there are a number of direct hydrocarbon indicators in the contract area.

Work by Togo Hunt Oil Company has identified several prospect and leads, involving Early to Late Cretaceous, and Tertiary reservoirs in a number of differing trap styles and geometries.