Think ahead and pass the salt

摘要

One of the most enduring myths surrounding oil exploration offshore West Africa is about the necessity of salt. The conventional wisdom stated that if you wanted to find a good quality source rock, and a decent seal to the reservoir, you needed to look in a salt province. Nigeria, where offshore structures are controlled by mud diapirs, was the obvious exception to this rule. The salt myth emerged as a result of Shell's 1967 discovery of the Gamba oil field in Gabon. The West African salt basin, extending offshore from Gabon, through Congo to Angola, became the next focus for oil explorers in the region. Subsequent discoveries seemed to prove the new axiom. The thinking was that any exploration outside the salt basin would find just small accumulations of oil or gas.