The discovery is in the Mronge-1 well off the East African County.
Statoil said it estimates there are more than 2 trillion cubic feet of natural gas now at Mronge-1 and the discovery, its fifth off the Tanzanian coast, brings its estimate for the entire exploration area to more than 17 trillion cubic feet of natural gas.
Mronge-1 was drilled in deep waters. Statoil said the well reflects the success of a new drilling program for Tanzania, which began in September.
"The Mronge-1 well discovered additional gas volumes and furthers the potential for a natural gas development in Tanzania," Nick Maden, a vice president in charge of Statoil's exploration activities in the Western hemisphere, said in a statement Friday.
Statoil serves as the operator in the Tanzanian reserve area with a 65 working interest. Exxon Mobil Exploration and Production Tanzania Ltd. holds the remaining 35 percent interest.
The U.S. Energy Information Administration said in an April profile of Tanzania the country doesn't export natural gas but recent discoveries have increased its potential to become a gas exporter in the future.
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