The discovery of an additional 1-1.8 trillion cubic feet of natural gas in place at Mdalasini-1 brings the total of in-place volumes up to about 22Tcf in Block 2 alone.

The Mdalasini-1 discovery, located at a 2296m water depth at the southernmost edge of the block, has been made in Tertiary and Cretaceous sandstones.

Nick Maden, senior vice president for Statoil exploration in the Western hemisphere, said the Mdalasini-1 discovery marked the completion of the first phase of an efficient and successful multi-well exploration program offshore Tanzania.

Since the start of the program in February 2012, Statoil has drilled 13 wells and made eight discoveries, including Mdalasini-1.

"We still see prospectivity in the area, but after appraising the Tangawizi-1 high-impact discovery, which was made in March 2013, there will be a pause in the drilling to evaluate the next steps and to mature new prospects," Maden said.

While Statoil has drilled the Mdalasini-1 well with a 100% working interest, previously Statoil and co-venturer ExxonMobil have made seven discoveries in Block 2, including the five high-impact gas discoveries Zafarani-1, Lavani-1, Tangawizi-1, Mronge-1 and Piri-1, as well as the discoveries in Lavani-2 and Gilligiliani-1.

Statoil operates the licence on Block 2 on behalf of Tanzania Petroleum Development Corporation (TPDC) and has a 65% working interest. ExxonMobil E&P Tanzania holds the remaining 35%.

TPDC has the right to a 10% working interest in case of a development phase.

Statoil has been in Tanzania since 2007, when it was awarded the operatorship for Block 2.