Page 16: of Offshore Engineer Magazine (Jun/Jul 2015)

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The spice of life

Field of View

Statoil and ExxonMobil are seeking ways to develop the multi-trillion cubic feet of gas resources they have found in Block 2 ofshore Tanzania.

Elaine Maslin takes a look.

Transocean’s drillship ofshore Tanzania - Discoverer Americas

Photo by Paul Joynson-Hicks - AP – Statoil.

conference in Olso in April, 2296m water depth at the southernmost

Harald Eliassen, previously asset edge of the block.

manager on the Peregrino feld

The 14th well, and the last in the cur- offshore Brazil for Statoil and rent drilling campaign, is an appraisal well on Tangawizi; it is ongoing. The now the frm’s Tanzania offshore project director, says it is early

Ocean Rig Poseidon drillship was used in the frst exploration phase. days, but this will be an interest- ing project for the industry to

A crucial part of the drilling campaign was a drill stem test (DST) on Zafarani. watch with technology hurdles to overcome – not least when it

The Zafarani-2 DST was one of the deep- est tests ever done, in some 2400m water comes to designing pipelines that can cross the seafoor valleys in depth, Eliassen says. It tested two zones, fowed at a maximum 66 MMscf/d, 2200m deep water between Block 2 and the shoreline. constrained by equipment, confrming “The project is in the early the production potential, reservoir con- stages,” Eliassen told the event. nectivity and the extent of the Zafarani “We have a lot of work ahead of reservoir. The DST also gave a good f you speak Swahili, zafarani, lavani, us, both on technical solutions offshore, indication of the production potential tangawizi, mronge, piri, giligiliani on the LNG plant and with the authori- of the other discoveries, Eliassen says.

I and mdalasini are spices – saffron, ties. There is still a lot of time before we Statoil now has some 15-16 subsurface vanilla, ginger, horse radish, pepper, make a fnal investment decision. But professionals on the job to mature the coriander and cinnamon. still, it is an interesting project and some- understanding of the reservoirs already

To Statoil and ExxonMobil, they are thing you should keep an eye on.” discovered, he says. also the names of eight major gas felds “Thanks to the long campaign using

Discoveries (Lavani has been classifed as two, Lavani the Discoverer Americas, the JV main and Lavani deep), totaling some 22 Statoil was awarded operator- has also had a learning curve

Tcf of natural gas resources, which they ship of Block 2, which covers drilling in Tanzania, which has have discovered offshore Tanzania and about 5500sq km in 1500-3000m reduced the number of days are now planning to bring to the market. water depth, offshore Tanzania, to drill a well in Tanzania,”

Discovering the resources, 100km off in 2007. In 2010, ExxonMobil Eliassen adds.

southern coast of Tanzania, in 2200- farmed in, taking 35% interest. Once the latest appraisal 2500m water depth, was a challenge The joint venture’s exploration well, Tangawizi 2, completes in itself. Now the two frms are assess- campaign started in 2012, with (due this summer), Statoil will

Harald Eliassen ing how they are going to bring these 13 wells now drilled, compris- demobilize Discoverer Americas resources to market. The current concept ing nine exploration wells, one combined from Tanzania and, Eliassen says, enter front runner is a subsea-to-shore proj- exploration and appraisal well and three the next exploration phase where it will ect – using already proven and qualifed appraisal wells. evaluate further prospects and drilling in technology as much as feasibly possible. The Zafarani, Lavani, Tangawizi and Tanzania.

Statoil expects to take a fnal invest- Mronge reservoirs were discovered in

Connected reservoirs and deep canyons ment decision on the project in 2018, at 2013-2014. Piri and Giligiliani were dis- the earliest. First production is likely to covered in 2014. Earlier this year, Statoil The gas in Block 2 is dry gas. Statoil be start 2022-23, at the earliest. announced the Mdalasini discovery believes this will produce through

Speaking at the Subsea Valley in Tertiary and Cretaceous sandstones natural depletion, gas expansion and

June 2015 | OE oedigital.com 18 018_0615_field of view_Tanzania.indd 18 5/31/15 7:42 PM