The recent successful conclusion of prospecting at the Orca field led to the review, which was made public at the beginning of the week when the group published its results for the first quarter of the year.

Previous estimates pointed to between 45 trillion and 70 trillion cubic feet of recoverable natural gas at a time when the group had drilled over 30 wells in the deep waters of the Area-1 concession, in which it has a stake of 26.5 percent.

The consortium also includes Mozambican state company Empresa Nacional de Hidrocarbonetos (15 percent), Indian groups ONGC Videsh (20 percent) and BRPL Ventures (10 percent), Japan’s Mitsui&Co (20 percent) and Thai group PTT Exploration and Production (8.5 percent).

Along with the Area-4 concession, which Italian group ENI projects has around 93 trillion cubic feet of recoverable natural gas, the two blocks are, so far, the most promising in the Rovuma sedimentary basin, which has six concession area.

Recent figures from the Mozambican government, which expects exploration of liquid natural gas (LNG) to begin in 2018, point to reserves of 180 trillion cubic feet of recoverable natural gas in the region.

Anadarko Petroleum announced it had paid the Mozambican state US$520 million in capital gains tax on the sale of a 10 percent stake in the block to ONGC Videsh for US$2.64 billion.