Project Profile
Location: Sable Island, 10 - 40km NW of Scotian Shelf, offshore Nova Scotia
Start-up year: November 1999
Peak production: 120 mmcf (3.4 mcm) per day (2016-17)
Water Depth: 75 m
Upstream Gas Reserves: 85 billion m³ of recoverable gas reserves
The Sable Offshore Energy Project (SOEP) is a consortium based in Halifax, Nova Scotia which is attempting to locate and produce natural gas found near Sable Island on the edge of the Nova Scotian continental shelf in eastern Canada.
The SOEP consists of the six gas fields Venture, South Venture, Thebaud, North Triumph, Glenelg and Alma. These contain about 85 billion m³ of recoverable gas reserves. Sable is Canada\'s first offshore natural gas project. It began producing in late 1999. At that time, the lifespan of the Sable natural gas fields was projected to be 25 years. Most of the gas was shipped to New England via pipeline.
There are 21 production wells on the site. The first 12 wells, planned to be drilled at the Thebaud, Venture and North Triumph fields, were completed by the end of 1999. The drilling programme was shared between Rowan and Santa Fe (Canada). The Rowan Gorilla II and the Santa Fe Galaxy II were used. Previous drilling in the area has indicated the presence of high-temperature, high-pressure wells. The fields are being developed in two stages. The first phase of the Sable Island project saw the development of the Thebaud, Venture and North Triumph fields in November 1999.
Decommissioning
In 2016 there has been a lot of discussion in regards to the decomissioning of Sable. It has generated more than US$1.7-billion in royalties, however production at the project has been declining over the past 7 years. Decommissioning has not yet been definitely confirmed but if the finances are in place then it is thought that Exxon will begin decommissioning as early as 2017.
As part of decommissioning, it is looking at establishing an onshore base at Point Tupper in the Strait of Canso to dismantle project platforms. Point Tupper is one of three options, including a regional yard in Atlantic Canada or using an international facility.
Thebaud gas-gathering hub
Thebaud is used as the gas-gathering hub. North Triumph and Venture have been developed as satellite platforms, feeding into Thebaud. The central Thebaud complex consists of two bridge-linked platforms. The larger platform has accommodation for approximately 40 offshore production workers and support personnel. The second and smaller of the two platforms supports the wellhead and processing equipment and collects and dehydrates gas from all of the fields in production.
North Triumph and Venture
These will be developed by unmanned satellite platforms although they will be occupied as field operations require. The platforms will incorporate dry wellhead structures and minimal processing facilities to separate produced water from the gas and natural gas liquids.
Contracts
The Thebaud topsides facilities were fabricated by Kvaerner Oil and Gas at its Teesside facilities in a US$65 million contract. The North Triumph topsides fabrication contract was won by a joint venture between MM Industra and Brown & Root. The contract\'s estimated value is about US$13 million with about 90% of the 100% Canadian content coming from Nova Scotia. The Dartmouth-based Fabco/CKT joint venture won the US$16.7 million fabrication subcontract for the Thebaud and Venture accommodation modules. The US$13 million contract for the construction of the Thebaud and Venture jackets was awarded in April 1997 to the joint venture between MM Industra and Brown & Root. The scope of work included the procurement, construction, construction engineering, fabrication, loadout and seafastening of the two jackets and piles. The two remaining (Thebaud accommodation platform and North Triumph) jackets were fabricated by Texas-based Peter Kiewit Inc in its Corpus Christi yard. The steel wellhead jackets were installed on Thebaud and Venture at the start of the project and then a jack-up was used to pre-drill the wells over them. The jackets were installed in April 1998 by the crane vessel M7000.
Infield lines ranging from 5 to 55km, with an outside diameter of up to 457mm, are used to link the platforms with the Thebaud gas gathering hub. In all there will be around 175km of interfield pipelines to be installed. The gas and natural gas liquids from Sable Island are then transported through a two-phase subsea pipeline from Thebaud to the onshore facilities in the Country Harbour area. The pipeline will be 225km long, with an outside diameter of 609mm. The pipeline corridor was chosen to avoid significant fishing areas and other sensitive sites. The US$250 million pipelaying was carried out by Allseas in August 1999, using its giant pipelaying ship Solitaire. Halifax-based Shaw & Shaw (subsidiary of Shaw Group Inc) was awarded a contract for the anti-corrosion and concrete weight coating of subsea interfield flowlines across the Sable Island field and the main gathering line.
Operators:
ExxonMobil Canada Properties Limited
Shell Canada Limited
Imperial Oil
Mosbacher Operating Limited
Pengrowth Energy Trust
Contractors:
Allseas: Pipelaying contract
Kvaerner Oil and Gas: fabrication of Thebaud topsides facilities
MM Industra and Brown & Root: North Triumph topsides fabrication and construction of the Thebaud and Venture jackets.
Peter Kiewit Inc: fabrication of Thebaud accommodation platform and North Triumph jackets.
Shaw & Shaw (subsidiary of Shaw Group Inc): anti-corrosion and concrete weight coating of subsea interfield flowlines.
Decommissioning contract awards:
AMEC Black & McDonald (April, 2016)
Halliburton
Heerema Marine Contractors
Noble: Two-year plugging and abandonment well campaign. (February, 2017)
Subcontractors:
Aecon Fabco/Ckt Nova Scotia Ltd joint venture: fabrication subcontract for the Thebaud and Venture accommodation modules.