The Core project phase-1 involves the development of Southwark, Blythe and Elgood gas fields in the southern North Sea, UK.
Two normally unmanned installation (NUI) production platforms will be deployed in Southwark and Blythe fields.
The first gas from the project is expected in the third quarter of 2021.

The Core gas project phase-1 involves the development of three offshore gas fields namely, Southwark, Blythe, and Elgood, in the UK sector of the North Sea.

Independent Oil and Gas (IOG), the project operator, holds a 50% stake while CalEnergy Resources (UK), a subsidiary of Berkshire Hathaway Energy, holds the remaining 50% stake in the project. IOG completed the farm-out transaction with CalEnergy Resource for the Core Project assets, excluding Harvey field, in October 2019.

The Core gas project involves five production wells in the Southwark, Blythe, and the Elgood gas fields in phase one. The well stream from the fields will be transported onshore to the Bacton gas terminal in Norflok County, through the Thames pipeline.

A final investment decision (FID) for the phase-1 development of the Core project was reached in October 2019, while the field development plan was approved by the UK Oil & Gas Authority in April 2020.

The Core project phase-1 is expected to commence production in the third quarter of 2021. Three more offshore fields including Nailsworth, Elland, and Goddard are planned to be developed in phase two. An FID on Core project phase-2 is expected in 2021.

Location and discovery

The Southwark, Blythe, and Elgood fields are located in blocks 48/22, 48/23, and 49/21 in the southern portion of the North Sea off the coast of the United Kingdom. The water depth in the project area is approximately 30m.

The Southwark field was discovered by Conoco Phillips in 2000, while Burmah Oil discovered the Blythe field in 1966. The Elgood field was discovered by Enterprise Oil in 1991.

Core project phase-1 development plan

The Core project phase-1 development plan involves deploying two normally unmanned installation (NUI) production platforms in Southwark and Blythe fields. A total of five production wells will be drilled in this phase across the three fields.

The Southwark gasfield will be developed through three production wells connected to the Southwark NUI production platform that will be connected to the Thames pipeline by a new 5.7km-long, 24in-diameter export pipeline.

The Blythe field development will include a production well connected to theBlytheNUI production platform. The well stream from the Blythe platform will be transported to the Thames pipeline through a new 24.5km-long, 12in-diameter extension pipeline. The extension pipeline is expected to be installed in the third quarter of 2020.

The Elgood field will consist of a single well subsea development tied-back to the Blythe platform through a 9.1km-long, 6in-diameter subsea flowline and as well as a control umbilical.

Thames pipeline and reception facilities

IOG completed the acquisition of Thames pipeline and the onshore Thames Reception Facilities (TRF) at the Bacton gas terminal from Perenco UK, Tullow Oil, and Spirit Energy Resources in April 2018 and October 2019, respectively.

The Thames pipeline which was decommissioned in 2015 was earlier used to transport gas from the Thames area complex to the Bacton terminal. The Thames pipeline and TRF’s gas and liquids reception equipment will be refurbished and re-commissioned as part of the Core project phase-1 development.

The 90km-long, 24in-diameter Thames pipeline was laid from the Thames platform to TRF at the Bacton gas terminal. A 60km-long section of the Thames pipeline will be utilised by IOG to transport well stream from the Core project platforms. The proposed Southwark platform is located approximately 6km north of the Thames pipeline.

The Core project gas output will be processed at the Perenco UK-operated Bacton plant. The processed gas will be supplied to the customers through the UK’s National Transmission System.

Contracts awarded

HSM Offshore was awarded the engineering, procurement, construction, and installation (EPCI) contract for the Core project phase 1 platforms in August 2020. The contract involves the design, fabrication, and installation of the Southwark and Blythe normally unmanned installation (NUI) production platforms.

Petrofrac was contracted for the planning, design, and management of the wells for the project in June 2020.

Proserv received the subsea control system EPCI contract for the Elgood field in June 2020. The control system includes a master control station, a subsea control module, subsea distribution, and instrumentation.

Subsea 7 received the subsea, umbilicals, risers and flowlines (SURF) engineering, procurement, construction, and installation (EPCI) contract for the project in May 2020. The SURF contract scope includes connecting the Thames pipeline to the Southwark and Blythe platforms, laying an umbilical connecting the Elgood field to the Blythe platform, and associated subsea structures and tie-ins.