The Anning and Somerville gas fields are located within the Seaward production licence P2607 in the Southern Gas basin, offshore UK.

Australian oil and gas company Hartshead Resources (Hartshead), formerly known as Ansila Energy, is the owner and operator of licence P2607. The company is planning to jointly develop the two fields.

The concept selection report of the project was submitted to the North Sea Transition Authority (NSTA) in May 2022. A letter of no objection for the same was received in July 2022.

The submission of the final development plan, along with the final investment decision (FID), is expected by the second quarter (Q2) of 2023.

Licence P2607 details

Hartshead Resources was awarded the P2607 licence, which contains five contiguous blocks in the Southern North Sea, during the UK’s 32nd licensing round in January 2021.

The Seaward licence P2607 includes five blocks, namely 48/15c, 49/6c, 49/11c, 49/12d and 49/17b.

It consists of several gas fields, including some that are partially developed, as well as multiple exploration prospects. With a combined resource base of approximately 0.8 trillion cubic feet (tcf) of high-quality gas, the licence will be developed in three phases.

Phase I will cover the development of the Anning and Somerville gas fields, located in block 49/17b. The Hodgkin and Lovelace gas fields will be developed in phase II. Phase III will comprise 14 prospects with prospective resources of 344 billion cubic feet (bcf). The Anning and Somerville fields were earlier known as the Victoria and Viking Wx fields.

The multi-phased development of the production licence will provide a potential opportunity to serve the UK Government’s Bacton Energy Hub project, which would establish a hydrogen-led energy hub at Bacton, Norfolk, UK.

Natural gas from the licence is expected to be used as a potential feedstock for blue hydrogen generation.

Anning and Somerville gas fields reserves

The Anning gas field holds 145bcf of probable and proven gas reserves and 192,000 barrels of condensate. Initial production from a historical single frac in well, the 49/17-14, was 14 million metric standard cubic feet a day (Mmscf/d), while the estimated ultimate recovery from the well is 13bcf.

The Somerville gas field is estimated to contain 156.5bcf of probable and proven gas reserves, along with 208,000bls of condensate. Initial production of more than 45Mmscf/d was recorded from the historical two fracs in well 49/17-12, while the estimated ultimate recovery is 46bcf.

The peak production from the phase 1 development project is expected to be 140Mmscf/d.

Anning and Somerville development details

The proposed development plan for the fields involves three production wells from each field and two wireline-capable normally unmanned installation (NUI) platforms, with one platform at each field.

The two platforms are expected to provide better economic performance and reduced drilling risk compared to a single platform. The platforms are expected to work independently.

The platforms will be connected to Shell’s infrastructure through a subsea pipeline. Gas produced from the fields will initially be transported to the Leman platform, followed by the Bacton gas terminal for onshore processing and finally to the UK national gas transmission system.

Shell UK, a subsidiary of Shell, signed an agreement to carry out the engineering study to identify the preferred offtake route for the gas fields in August 2022.

To be conducted by Petrofac, the engineering study will provide the cost estimate and design for the probable offtake route and required brownfield facility changes.

The infrastructure developed for Phase I is planned to be used to monetise phase II and phase III resources as well.

All the wells are expected to come on stream in 2024.

Contractors involved

Llamas and Bannister (LAB) Energy Advisors, an energy advisory company, was appointed to advise on industry partnering for the project in June 2022.

UK-based global energy consultancy ERC Equipoise was selected to provide an independent evaluation of the reserves and resources for the phase I development in April 2022.

Xodus Group, an energy consultancy and a wholly-owned subsidiary of Subsea7, was awarded a contract to provide surface geology and geophysics services for the project in June 2021.

In the same month, Petrofac was contracted for a pipelines, facilities, safety and environment study, while Fraser Well Management, a well engineering and management services company, was selected to conduct a well construction evaluation for the project, and Fenix Consulting Delft, an engineering consulting company, was awarded a contract for frac modelling and design of horizontal multi-frac well completions for the project.

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