Tanzania partners plan deepwater drillstem tests

Appraisal continues on the deepwater Mzia gas field offshore Tanzania.

Offshore staff

LONDON – Appraisal continues on the deepwater Mzia gas field offshore Tanzania. BG operates surrounding block 1 in partnership with Ophir Energy.

The Mzia-2 well was drilled in 1,622 m (5,321 ft) of water, 4 km (2.5 mi) southeast of the 2012Mzia-1 discovery well. It encountered 62 m (203 ft) of net gas pay in Cretaceous reservoirs and established pressure communication between the Mzia-2 and Mzia-1 gas columns. The result, Ophir says, confirms a vertical gas column of at least 200 m (656 ft) for the field.

Flow testing is now under way on block 1, with the drillshipDeep Sea Metro on location at the Jodari field to test Oligocene-age reservoirs. This program, the first drillstem test (DST) in the deepwater Tanzania area, should be completed by end-February.

Another DST should follow on Mzia-2 to confirm deliverability from the core part of the Mzia field. However, test rates from the Cretaceous are likely to be lower than from the Tertiary due to differences in burial depth and relative parameters of the two reservoir types.

Thereafter, the partners will revert to exploration drilling with two potential wells, the first of which will be on a target identified on a recently acquired outboard block 1 3D dataset.

Additionally, they have commissioned a 2,500-sq km (965-sq mi) 3D seismic survey in the inboard area of the block to investigate further resources and mature new drilling targets. That program is expected to be completed in late March.


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