Ophir Energy believed that a merger would create the potential for a "well-funded, re-focussed, full cycle Exploration and Production company."
Such a merger would have created a company with market capitalisation of more than £3bn.
In March, Ophir Energy reported net loss after tax of $245.8m (£149m) in 2013, compared to $40.7m in 2012, reflecting writedowns on assets in Tanzania and exploration write-offs in Ghana, Madagascar, Congo and Kenya.
The FTSE 250 company also outlined its plans to deliver “the most extensive exploration plan in Ophir’s history” this year, targeting wells in Tanzania, Gabon and Equatorial Guinea.
“This programme will include several new plays, which, if successful, have significant follow on potential beyond any initial discovery,” said chief executive Nick Cooper.