Tullow Oil said its West African production exceeded expectations in 2017 by averaging 89,100 barrels of oil per day.
In Europe, meanwhile, working interest gas production performed in line with expectations, with full year net production averaging 5,600 boepd.
Tullow said it expected to report revenue of around $1.7bln and gross profit of around $0.8bln for 2017. It also expected to have generated $0.5bln of free cash flow, significantly exceeding a forecast at the start of the year.
Capital expenditure in 2018 was expected to total approximately $460m.
"Tullow delivered strong operational and financial performance in 2017 against the backdrop of continued industry volatility," chief executive Paul McDade said.
"Over 2018 we expect to continue this positive momentum. With our diverse low-cost assets and high-graded exploration portfolio, enhanced by recent licence additions in Côte d'Ivoire and Peru, we have a strong foundation to grow the business and further reduce our debt."