The London-listed oiler has a 40% interest in the project alongside partners Woodside, the operator with 35%, and FAR with 15%, whilst the Senegal National Oil Company Petrosen has 10% (with the option to increase up to 18%).
Sangomar is described as being “on target to be a project of national significance and an anchor for economic and social development in Senegal.”
The field development follows three phases of drilling, between 2014 and 2017, in which eleven wells were successful.
Cairn noted that more than US$1bn has so far been invested in Senegal in connection with the project, and, a further US$4bn is anticipated to deliver the field and achieve first oil by 2023.
"Cairn's discoveries offshore Senegal from the country's first deep water wells opened up a new basin on the Atlantic Margin,” said Simon Thomson, Cairn chief executive.
“Cairn has operated three drilling programmes and successfully laid the foundation for Senegal's first multi-phase oil and gas development.
“Senegal is now an attractive oil and gas province, drawing the attention of the global industry."
The Phase 1 development will address some 231mln barrels of oil reserves, and, it will utilise a floating production storage and offloading (FPSO) facility, with a 100,000 barrels per day production capacity.
Key contractors have been appointed for the FPSO, subsea infrastructure and well drilling.