BG Group announced in a press release an increase in total recoverable resources for the Mzia discovery and across blocks 1, 3, and 4 offshore southern Tanzania, marking the conclusion of a successful drilling and testing campaign.

The campaign confirmed Mzia as the second largest gas discovery, after Jodari, in BG Group’s acreage offshore Tanzania, with 133 Bcm (4.7 Tcf) of total gross recoverable resources, according to the release. Total gross recoverable resources across BG Group’s blocks 1, 3, and 4 are now estimated to be around 424.8 Bcm (15 Tcf) with further exploration upside.

The Mzia-3 appraisal well, drilled approximately 6 km (3.7 miles) north of the original Mzia-1 discovery in 1,780 m (5,840 ft) of water, has been cored and logged. Results confirm the reservoir sands are extensive and of similar quality to those found in the Mzia-1 and Mzia-2 wells, according to the release. In addition, the gas-down-to level proven in Mzia-3 is around 100 m (328 ft) deeper than that of Mzia-2.

Further north, detailed technical analysis of the Block 4 discoveries Chewa, Ngisi, and Pweza – which also were appraised and tested in the campaign – was positive with total gross recoverable resources in the block now estimated around 141.6 Bcm (5 Tcf). This means an extensive exploration and appraisal campaign of 14 wells started in 2010 offshore Tanzania has had a 100% success rate with nine consecutive discoveries and five appraisal wells, three of which included drillstem tests showing high flow rates, according to the release.

BG Group as operator has a 60% interest in blocks 1, 3, and 4 offshore Tanzania, with Ophir Energy holding 40%.

BG Group has transferred the Deepsea Metro-1 drillship to Ophir Energy for a one-well campaign. The vessel will then return to BG Group for one exploration well in Kenya next year before going back to Tanzania for further exploration and appraisal activities in Block 1, including a drillstem test on Mzia-3 later in 2014, BG Group said.