The survey, known as Sierra Leone Block 4A Extension, will merge the 1,000 km² of new 3D data to the existing 6,268km² of 3D data library in the region.
TGS Eastern Hemisphere Senior vice president Stein Ove Isaksen said: "This survey extends our current data coverage in an important and prospective area.
"TGS has been active in acquiring data over the West Africa Transform Margin for the past decade and we are pleased with the level of customer support to continue our investment in this region."
The Norwegian firm is chartering the 12-streamer Polarcus Alima for the survey, which will secure funding from the oil and gas industry.
