Until recently, the partners in Block 31 had been hoping for the go-ahead from state oil company Sonangol in the second quarter.
However, Marathon Oil was not specific, talking only about sometime this year.
Contracting sources privately said they would be surprised if anything of importance happened before the end of the year.
It is unclear what the hold-up is although sources outline a number of possibilities such as continuing local content deliberations plus parliamentary elections planned for September this year, followed by a presidential run-off in 2009.
Contractors
