Aberdeen-based Eland said the Elcrest venture had made good progress in talks with relevant government departments in Nigeria about its tax status.
"Elcrest expects to benefit from a significant reduction in underlying tax rates," said Aim-listed Eland.
The company said it would provide further detail when appropriate.
Eland started production from the OML 40 licence in Nigeria last month, following delays on a project to revamp a field that was shut in by Royal Dutch Shell amid security concerns.
It has an interest in OML 40 through its 45% holding in the Elcrest venture.
Elcrest has 45% of OML 40.
State-owned NPDC has 55%. Shares in Eland closed up 3.5p, at 121p.