BG Group says the results of a second drill-stem test (DST) on the Mzia discovery in Block 1, offshore southern Tanzania, has provided further support for a hub development to supply an onshore LNG project.
The DST in a side-track on the Mzia-3 appraisal well, drilled in about 1800m water depth, about 6km north of the original Mzia-1 discovery, included sustained gas production at a maximum flow rate of 101MMscf /d, equivalent to about 17,000boe/d.
According to partner Ophir Energy, the well flowed slightly ahead of expectations at an average controlled rate of 90MMcf/d for six days, with the peak 101MMscf/d rate constrained by equipment limits.
Nick Cooper, Ophir’s CEO, said: “The Mzia-3 flow-test is another positive result on what will be a core asset in our Tanzanian LNG development. Momentum continues to build on that project with pre-FEED contracts awarded on both the midstream and pstream portions of the development.”
Mzia, discovered in 2012, is a multi-layered field of Upper Cretaceous age with a gross gas column in excess of 300m. The Mzia and Jodari discoveries in Block 1 are estimated to hold around 9 trillion cubic feet (Tcf) of total gross recoverable resources, with around 15 Tcf of total gross recoverable resources, around 2.5 billion boe, across Blocks 1, 3, and 4.
Ophir said the data acquired from the latest Mzia-3 DST and cores from the Mzia-3ST1 well will now be incorporated into planning of the production wells as part of development of the field.
An earlier DST on the Mzia-2 well, performed in May 2013, was the first done on a Cretaceous discovery in deep water offshore Tanzania. It flowed at an equipment-constrained rate of 57MMscf/d, or around 9500boe/d.
Sami Iskander, BG Group’s CEO, said: “The excellent results from this latest drill-stem test further reduce reservoir risk, a critical factor as we progress design of the upstream production facilities and infrastructure. Also, the Mzia-3 DST, along with previous appraisal activities, supports our efforts to optimise the value of a development across our Block 1 discoveries.”
The drill ship, the Deepsea Metro-1, which was used for the Mzia-3 appraisal well, will now move north to complete the exploration and appraisal program on the Block 4 discoveries by drilling the Kamba-1 well.
BG Group has a 60% interest in, and is operator of, Blocks 1, 3 and 4 offshore Tanzania, with partner Ophir Energy holding 20% and Pavilion Energy 20%.
Ophir Energy also gave an update on its Equatorial Guinea drilling. It said the Tonel North-1 appraisal well had been completed on Block R, Equatorial Guinea. The Tonel North-1 well was drilled about 5km north-east of the original Tonel-1 discovery well. The well encountered gas pay combined in the lower target sands but the upper sands appeared to be low gas-saturation. Analysis of the well data is ongoing. The result is expected to marginally reduce the discovered volumes in the Tonel field but will not impact the commerciality of the base case 2.5MMt/pa FLNG project, Ophir said.
The Vantage Titanium Explorer drillship, which drilled the well, has now moved to complete the Silenus East-1 exploration well, which is targeting ca.420Bcf of low-risk mean prospective gas resource as a primary target and will be deepened to test a secondary, high-impact but high-risk oil target that on current mapping could be a potentially extensive play across the Block.
The top hole of Silenus has already been previously drilled and the well is expected to complete within two weeks. There are several analogous shallow gas prospects to Silenus East in the Thrust Belt play sharing the same Direct Hydrocarbon Indicators. If successful, the well would de-risk ca.1.2Tcf of upside (including Silenus East volumes) in the immediate area that could provide an additional production hub for the FLNG development.
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