Jeffgw,
There are a few helicopter companies in Nigeria: Bristow, Aero Contractors, Caverton and OAS.
OAS is a Nigerian company and very small with just a couple of AS350Bs. It operates from Lagos and Port Harcourt. I don't think they pay much and I'm not too sure of whether they do much for providing for your personal security ( a must if you're flying in the Niger Delta region).
Caverton is also a Nigerian company and small, but just about to start a contract with Shell. They have a couple of Bell 412 EPs belonging to Lagos State Government, a couple of AS350B2s which do charter work and will shortly be taking over operating the EC155Bs owned by Shell. They are presently based in Lagos and Port Harcourt, but will also start in Warri in October.
Aero Contractors is now a wholly Nigerian company and operates a number of SA365, EC225 and S76 series for offshore oil and charter contracts. They have bases in Lagos, Warri and Port Harcourt.
Bristow is a joint Nigerian/American venture and operates B206/407, S76 series, S92, Bell 412 EPs, EC155Bs and AS332 series for oil company contracts. They have bases in Lagos, Escravos, Warri, Port Harcourt, Eket and Calabar.
The likelihood of your getting a job depends on whether you have offshore experience, an instrument rating, twin time and an absolutely minimum of 1,500 hours. I've been operating in this part of the world for over 30 years now and if you PM me with some details about yourself I can give you some advice.