From what I hear, although everyone says Tanzania is a lovely place compared to Nigeria, there's not much going on there this year apart from the Statoil contract. CHC had a problem because the Tanzanian CAA wouldn't allow them to carry on flying on the Canadian registration and they lost their S76 contract to Everett, but I think they still have an AW139 in Mtwara, near the Mozambique border flying for BG? I don't know if they've changed the aircraft registrations yet though?
Although Everett won the Statoil contract and has the Tanzanian AOC all the 139s are leased from, flown and engineered by Bristow. Bristow International has a problem getting people to go there because they're not paying enough (much less than here in Nigeria) and Everett can't get anybody because they pay a lot less than Bristow.
There is a lot of interest in that part of Africa for gas and Kenya and Mozambique have also had a lot of seismic surveys done, but it looks as if Statoil and BG are the only ones doing much of anything this year.
I heard that Starlite Aviation are also looking at Tanzania and may have already applied for an AOC. They seem to be doing pretty well and are expanding so maybe they'll also be there later this year or next year if things pick up.