MonArb Area Redevelopment Project (MAR), North Sea

Offshore Group Newcastle (OGN) bagged the engineering, procurement and fabrication contract for the jacket of the bridge-linked platform for the MonArb redevelopment project. Image courtesy of OGN Group.

Montrose Alpha Platform was originally installed in 1976.

The two main fields Montrose and Arbroath are located in blocks 22/17 and 22/18, about 209km east of Aberdeen in the North Sea. Image courtesy of Idarvol.

The MonArb Area Redevelopment Project (MAR) or Montrose Area Redevelopment (MAR) plan comprises redevelopment of the Montrose, Arbroath, Brechin, Arkwright, Carnoustie and Wood fields, and development of two new fields Cayley and Shaw. The two main fields Montrose and Arbroath are located in blocks 22/17 and 22/18 about 209km east of Aberdeen.

The project, which is being carried out by Talisman (51%) and Sinopec (49%), was approved by the UK Government in October 2012. The MAR project will extend the life expectancy of the existing six oilfields to 2030 to produce a further 100 million barrels of oil equivalent. First gas and oil from the Shaw and Cayley fields are expected in 2015.

The project is being carried out with a brown field allowance (BFA) of £1.6bn ($2.4bn) creating up to 2,000 jobs. A $285m contract for the subsea development works of the project has been awarded to Subsea 7.

Geology, discovery and location of the oilfields

Hydrocarbons and oil at Montrose and Arbroath are found in kimmeridge clay formation within the Palaeocene forties sandstone and in mudstones of the Sele Formation. Montrose was discovered in 1971 and began production in 1976, while Arbroath was discovered in 1969 and began production in 1991.

Cayley was discovered in 2007 by the well 22/17-3 which was drilled about 10km west of Montrose at water depths of 91m. The field will be developed through two production wells.

Shaw was discovered in 2009 by the well 22/22a which was drilled by Talisman in collaboration with Marubeni. The field is located about 17km north of Montrose and will be developed through three production wells and two water injectors. The wells will be ultimately tied to the new Montrose bridge-linked platform (BLP).

Project details of the MonArb area redevelopment

A bridge-linked platform will be constructed and attached to the redeveloped Montrose Alpha Platform, which was originally installed in 1976. The bridge-link will measure 71m in length and weigh 350t.

The subsea development works will include the fabrication and installation of two 5km pipeline bundles. The pipeline bundle system will tie back the Cayley production wells to the new BLP at the Montrose Platform. The works will also involve the fabrication and installation of a 17.5km production pipeline, water injection pipeline, gas lift pipeline and control umbilical which will connect Shaw Field to the BLP.

The pipeline bundle will be installed at its offshore location using the Controlled Depth Tow Method. The development will also involve the drilling of six additional infill wells from the Montrose platform using a modular rig.

The BLP jacket, which will weigh 5,400t and measure 118m in length, is expected to be delivered in 2014. The modification works for the bridge at Montrose are also expected to be carried out in 2014. The topsides for the BLP and the bridge installation works are expected to be completed in 2015.

Oil will be exported using an existing flowline into BP’s Forties Pipeline system and further to the Cruden Bay Pipeline using an existing export riser at Montrose. Gas will be transported through a new riser into the existing WAGE (Wood And Gas Export) module at the Montrose Platform, which will be tied into BP’s Central Area Transmission System (CATS) that runs to Teesside.

Contractors involved in the MonArb offshore project

The contract to supply a new drilling rig for the project has been awarded to Transocean. The company will supply its Sedco 712 rig to carry out certain drilling works. The value of the contract is £290m ($432m).

A contract worth £50m ($74.6m) for the engineering, procurement and fabrication of the jacket for the drilling rig was awarded to Offshore Group Newcastle (OGN) in 2012. The topsides for the bridge-linked platform will be constructed and supplied by AMEC.

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