Exploration company Tullow Oil said it had raised an additional $450m of capital from existing lenders.
This will boost its financial strength despite weak oil prices and sent its shares higher.
Tullow, which posted its first loss in 15 years last year, said its total committed debt facilities were now around $6.3 billion with no near-term maturities, placing it in a strong financial position.
Tullow's lenders have agreed to extend existing commitments by $200m, increasing available debt to $3.7 billion.
It also secured an additional $250m through a corporate debt facility that has now risen to $1 billion.
"Today's announcement demonstrates the resilience of our debt capital structure and the quality of our portfolio to generate significant liquidity, even at low oil prices," Ian Springett, Tullow's chief financial officer, said.
The Africa focused company also said today that it had amended its debt agreements in a way to shield itself from any potential covenant breaches.
Shares in Tullow fell two weeks ago when news emerged that a maritime border dispute between Ivory Coast and Ghana could delay one of its flagship oil projects.
