US supermajor Chevron has taken a final investment decision to develop the high-pressure high-temperature Alder gas and condensate field in the central North Sea.

The San Ramon, California-headquartered giant aims to see first production in 2016 at the subsea development, which has a design capacity of 110 million cubic feet of natural gas and 14,000 barrels of condensate per day.

Vice chairman George Kirkland said that Alder ranked among the explorer’s “solid queue of major capital projects” planned to profitably grow production.

Situated around 160 kilometres off the coast of Scotland in 150 metres of water, the field was discovered in 1975 but never developed due to the technical challenges involved.

“Our decision to proceed with this valuable asset was enabled by the right combination of technology, commercial conditions and knowledge sharing on high-pressure high-temperature experience,” commented Chevron Upstream Europe managing director Craig May.

Chevron operates the Block 15/29a project on a 73.68% stake with ConocoPhillips holding the other 26.32%.

Chevron’s plans have been approved by the UK’s Department of Energy & Climate Change and the field is benefiting from the UK’s tax allowance for small fields.

Alder is to be developed via a single subsea well tied back to Chevron and ConocoPhillips’ Britannia platform 28 kilometres away.

Total recoverable resources at Alder range up to 4.82 billion cubic metres of gas over a ten-year lifespan, according to a previous estimate.

Over the past year Chevron has dished out a series of contract awards for Alder, for which the explorer says 75% of development work will be carried out in the UK.

Dolphin Drilling is to sink the subsea well using the Fred. Olsen Energy-owned Blackford Dolphin, which is contracted to Chevron until mid-2015.

ConocoPhillips will build a new dedicated module on the bridge-linked platform to process produced fluids from Alder.

Technip has been contracted to provide detailed engineering, procurement, installation and commissioning of the complete subsea system for Alder, including the main subsea manifold, subsea isolation valve manifold, 28 kilometres of pipe-in-pipe flow line, umbilical and tie-in spools.

OneSubsea UK is to design, manufacture and supply two high-pressure high temperature vertical subsea monobore trees and wellheads.

Aker Solutions is to design, manufacture and supply the subsea control system, including the hydraulic and electrical components to be installed both at subsea and on the Britannia Bridge Linked Platform.

Gas will be exported to the Scottish Area Gas Evacuation (SAGE) terminal at St Fergus.

The decision to go ahead with the development contrasts with November’s surprise decision by Chevron to put its Rosebank development in the North Sea on hold pending a review of its scope and economic viability.

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