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Concept selection some aquifer support, with a recovery development, and took that concept fur- rate ranging from 60-80%. “It all depends In choosing its development concept for ther – making it event leaner. on how much water support we get,” Block 2, Statoil looked at foating LNG, “The concept is a daisy chain layout,

Eliassen says. “We need some to keep the a foating production unit offshore, with with no manifolds, no large modules to pressure up, but we don’t want too much the gas going into the shore for LNG pro- be lifted, simple inline Ts on the fow- water support because the water might duction, and subsea to shore. lines to connect each well, too,” Eliassen

Field of View “The foating LNG was hot for a while,” break through and we might have to shut says. “It allows us to spread the Xmas

Eliassen says, “But, as we made more the wells.“Since we will produce several trees around on the seabed so we have an and more discoveries we realized that the discoveries into one common production easier well path and lower drilling costs. amount of gas doesn’t really ft the foat- system we have to manage to pressure All of this made the system a lot cheaper ing LNG system – it would be too small or depletion in the different reservoirs so and we managed to cut something like we can reach a common pres- 30% of the cost from the sure in the pipeline system,” he original system we had. continues. “With the depletion Cutting cost on this project and gas expansion as the main is very important. It’s a huge drive there will be no injection investment project.”

Statoil is now going into wells.” an equipment and technology

It is thought that the Zafarani selection phase. Eliassen is reservoir will need 5-7 wells, very clear that the company the Piri reservoir 3-5, Lavani only wants already proven deep 2-3, and Lavani main 3-5 equipment and technologies wells. In total, that will add as far as is feasibly possible. up to about 13-20 wells in the “We don’t want to go into any frst phase of development. The technology development pro- results of the appraisal well on grams or technology qualifca-

Tangawizi-2 will help decide if tion programs that we don’t

Tangawizi is feasible and eco-

Statoil staf Geir Rune Hagatun and Nicholas Alan Maden on the absolutely have to do,” he says. nomical to develop, and if so,

Discoverer Americas ofshore Tanzania. Photo from Statoil “We need to get together with this would probably be added you’d need too many units out there and industry and our partners – ExxonMobil to the production some 7-10 years after it would become very expensive.” The has a lot of ultra-deepwater experience – frst gas. It would add another 5-8 wells

Tanzanian government was also very keen to fnd out if there’s anything out there we and probably a second pipeline to the for onshore processing, to bring benefts can use copy and standardize. If there is, development, Eliassen says. to the local economy. we will do it in Tanzania.”

Then, there are the Mronge, Giligiliani

Statoil then compared a foating unit and Mdalasini reservoirs. These have

Onshore offshore with a subsea-to-shore sys- not been included in the frst phase of tem. “Both were technically feasible,” development, partially due to the diffcult Based on a request by Tanzanian

Eliassen says, “So we looked at con- seabed conditions. From the Tanzanian authorities, the onshore processing cept differentiators to see if there was shoreline extending out to sea there are terminal will be built under a partnership anything with a foating unit that would some very pronounced canyons and val- between the operators on Blocks 1, 2, 3 give us a higher recovery factor, better leys, Eliassen says. (OE: February 2015) and 4, led by BG Group. economy, less risk, etc., and we really “Where our discoveries are, the valleys A memorandum of understanding didn’t fnd anything that would pay for become even more pronounced. They between the government of Tanzania, the extra cost of the foating production are 200-300m deep with very steep edges the partners in Blocks 1, 3 and 4 and the unit. So, due to the lower capex, opex and possibly unstable edges,” he says. partners in Block 2 was signed in April and lack of differentiators, we ended up “Luckily, most of our discoveries are in 2014. A contract for the LNG plant pre- with a subsea-to-shore solution with the the core areas between these pronounced FEED was awarded in August 2014. A gas transported untreated to the LNG canyons. That’s why we’re starting with joint integrated project team is working plant to shore.” in this area and we have found a feasible on the project in London working on the route for the pipeline to shore, too.” onshore project.

A subsea system But, it will not be easy. “There are still “We believe we’ve found a feasible and some valley crossings [on the pipeline Statoil looked at what it had done before cost effective solution – subsea to shore export route]… and there are still some on the Ormen Lange subsea-to-shore into a common LNG plant,” Eliassen issues related to that, but we believe that project offshore Norway. This created says. “There are still some challenges, together with industry we will be able a concept with large manifolds, dual notably on the seabed in 2500m water to fnd solutions to protect the pipelines pipelines, dual services lines, dual depth and we need to work together with so they can withstand any activities in umbilicals, “loads of redundancy.” This the industry and our partners to come these canyons. We can see there was was seen to be too expensive and would up with cost effective solutions for this some activity about 500 years ago and require mobilization of heavy lift vessels development.” that is not long enough ago for us to rule to Tanzania, where there were no heavy Statoil’s Tanzania offce, in Dar es it out that it will not happen while we are lift vessels before. The frm then looked Salaam, has about 50 people, mostly local there.” at its leaner Snohvit subsea to shore with about 15-20 people Norwegians.

June 2015 | OE oedigital.com 20 018_0615_field of view_Tanzania.indd 20 5/31/15 7:42 PM