The Norwegian company said its Lavani-2 exploration and appraisal well in 8,400 feet of water yielded a new natural gas discovery in Tanzania.
"When deepening the well to the second target, a separate and significant gas bearing reservoir ... was encountered," Statoil said.
Statoil is working in the region with Exxon Mobil. The Lavani-2 is the venture's third discovery offshore Tanzania this year.
"The discovery is important for Statoil's international growth and demonstrates how Statoil's exploration strategy of focusing on high-impact opportunities is paying off," Statoil said.
The World Bank announced last year it approved an International Development Association credit of $27.8 million to back Tanzania's energy expansion projects. U.S. officials had said a lack of energy is one of the main reasons for slow development in the region.