Tectonic Impact On Regional Structural Trends in Ultra Deep Water Cape Three Points

ABSTRACT

A 3D seismic data merged with a regional 2D seismic data and well data acquired from Ghana National Petroleum Corporation were used to determine the tectonic impact on regional structural trend in the Ultra-Deep Water Cape Three Points. The Cape Three Point basin was fashioned from transform tectonic and has been severely influenced by the largest tectonic feature in the central Atlantic Ocean, the west-southwest – east-northeast (WSW-ENE) romanche fracture zone. The study area lies over water depth of 100 m in the east and 2500 m in the west. In the cube (three dimensional seismic data) four (Intra Late Albian, Cenomanian Unconformity, Top Cenomania and Seabed) surfaces were interpreted in addition to the interpreted regional seismic lines.

Regional scale faults a long WSW-ENE (regional 2D) seismic line had NE-SW trend forming half gardens in the pre rift block accommodating syn rift sedimentation. In map view syn-rift faulting were trending NW-SE. This extensional regime in the study area was characterized by growth faults, relay structures and rotated fault blocks. Faulting died before Top Cenomanian. Moving deeper into the basin compression produced ridges (three-way dip structures) which were trending NE-SW. The post-rift formation was characterized by polygonal faults. Tertiary sequence had an unconformity probably as a result of fall and rise in sea level. NE-SW Canyons also incised the seabed.