Africa-focused Tullow Oil said the challenge for 2016 was to navigate the weakened market with key offshore priorities intact while cutting investments.

Tullow said revenues were down 27 percent for the year. Net debt rose to $4.0 billion for the year, compared with $3.1 billion for the previous year. Losses narrowed, however, from year-end $197 billion from 2014 to $1.09 billion last year.

CEO Aidan Heavey said in a statement the narrowed loss in 2015 showed the company was able to weather last year's market downturn well enough to market good delivery from West African positions.

"Our challenge in 2016 is to be equally robust in responding to the uncertainties that remain in the sector," he said.

Crude oil prices declined 34 percent for full-year 2015 and another 14 percent this year to trade Wednesday at around $30 per barrel. Tullow said the cost per-barrel in most of its offshore operations in West African range from about $8-$15 per barrel.

Heavey in January said savvy maneuvering last year left his company with "financial headroom" of $1.9 billion to start 2016. The company plans to spend about $900,000 million this year, about 19 percent less than previously expected. Spending last year amounted to $1.7 billion.

In terms of production, the company said its West African basins averaged 66,600 barrels of oil per day last year and should move as high as 80,000 bpd this year.

In December, Tullow, which has headquarters in London, sent its full development plans to the Ghanaian government for the offshore Jubilee field, which could help drive the production figures for this year.

Progress on the Tullow-operated Tweneboa Enyenra Ntomme, or TEN field, is nearly complete and on schedule for the first batch of produced oil by the summer. At its peak, the company said the prospect is expected to produce about 80,000 bpd.