Tullow gained as much as 13 percent in London trading, the biggest intraday gain since Dec. 11. The shares were 44 pence higher at 779 pence as of 10:05 a.m. local time.

The new loan is split between a Senior Facility of $1.785 billion, a Junior Facility of $100 million and $115 million from the International Finance Corp., the World Bank’s private-sector lending arm, with a final maturity of December 2015, Tullow said in a statement. The margin on the Senior and IFC facilities, depending on the level drawn, is up to 3.75 percentage points over the dollar London interbank offered rate.

Banks

The loans have been provided by BNP Paribas SA, Royal Bank of Scotland Group Plc, Barclays Plc, Calyon, ING Bank NV, Lloyds TSB Bank Plc, Natixis SA, NIBC Bank NV, Societe Generale SA, Standard Bank Plc, Standard Chartered Plc, Sumitomo Mitsui Banking Corp. and Bank of Scotland Plc, the oil explorer said.

Separately, Tullow said it “discovered a significant highly-pressured light hydrocarbon accumulation” in the Deepwater Tano license offshore Ghana.

The Tweneboa-1 well was drilled to a depth of 3,593 meters (11,800 feet) and is currently being drilled deeper “to further assess the discovery and the up-dip limit of a potential deeper fan system.”

The discovery marks a “considerable success,” Job Langbroek, an analyst at Dublin-based Davy Stockbrokers, said in a research note today. “The well could have a material impact on the exploration program in the offshore Ghanaian blocks as the next well could be a follow-on to Tweneboa.”

 Kosmos Energy LLC, Ghana National Petroleum Corp. and Anadarko Petroleum Corp. also hold stakes in the Deepwater Tano license.