GESGB Aberdeen Evening Lecture – May 2024 (Hybrid)

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Speaker: Colin Percival – Athena Exploration

Topic: West of Shetland Gas – Chasing the Remaining Giants on the UKCS

Date/Timings: Tuesday 14 May – 18:00-19:00 (doors open at 17:30)

Venue: Inn at the Park, Ferryhill, AB11 7RX (free parking provided)

Catering: Self-funded bar

Online: The presentation will be available to view via live stream on Zoom. Login details will be sent to registered attendees one day prior to the event.

West of Shetland Gas – Chasing the Remaining Giants on the UKCS

The North Sea Transition Authority estimate the UKCS yet to find is around 15 billion boe. Of this total 5.5 billion boe (37%) lies in the West of Shetland with a significant proportion expected to be gas. The 5.5 billion boe largely sits at the play level (4.7 billion boe) with only 0.8 billion boe in mapped prospects and leads. Good quality seismic and AVO analysis is required to convert the play level volumes into robust, low risk, drillable prospects. Evaluation of recently reprocessed seismic data indicates that large standalone low risk gas prospects exist, many in moderate water depth with modest target depth. Success at any one of these prospects would be sufficient for a new era of gas development West of Shetland. This would also unlock the significant gas discoveries in the area which are currently stranded due to their size.

Historically gas has had negative value West of Shetland. Companies have preferentially targeted oil, and any associated gas required disposal typically by reinjection. Output from oil fields such as Foinaven and Schiehallion was initially constrained by the injection capacity of the gas disposal wells. This led to the development of the West of Shetland Pipeline System (WOSPS) to evacuate gas from these fields via Sullom Voe to Magnus where it was injected into the reservoir to enhance oil recovery. WOSPS did not provide an evacuation route for third party business until very recently when oil production and associated gas production from these fields had significantly declined. The first dedicated gas evacuation system was the Laggan-Tormore (Palaeocene) development tied back to the Shetland Gas Plant. Underperformance of these fields and the discovery of an oil leg in Tormore resulted in reduced throughput, and exploration close to the pipeline was undertaken to provide additional gas volumes. The Edradour (Cretaceous) and Glenlivet (Palaeocene) gas discoveries were subsequently tied in to provide additional gas volumes. Both gas evacuation systems now have ullage and a 2km pipeline to connect the two currently independent systems on Shetland is underway. The availability of ullage in the existing gas infrastructure and the ability to develop West of Shetland gas from onshore with extremely low emissions < 5kg CO2e per boe herald a potential new era for this province. It has few of the issues that prevail in mature areas such as ageing infrastructure requiring electrification and competition for offshore space. It is the only UKCS basin that can deliver a significant number of large (>100mmboe) low risk prospects and provides a compelling resource for the UK during the energy transition.

Colin Percival – Athena Exploration

Colin is Technical Director at Athena Exploration which holds 4 licences in the West of Shetland. He has more than 40 years’ experience in oil and gas, having started his career working offshore before joining BP in 1981. He has worked the UK offshore and internationally throughout this time and has been involved in all UKCS Licensing Rounds since the 10^th Round. Colin is a member of the UK Subsurface Task Force where he leads the Domestic Oil & Gas Subgroup.

Colin has a first-class degree in geology from Reading University and a Ph.D. in sedimentology from Durham University. He was President of the Petroleum Exploration Society of Great Britain in 2016. He is a proven oil and gas finder with successes in all the main basins of the UKCS as well as West Africa and the Netherlands and has been actively involved in all types of commercial deals from farmins/farmouts to corporate acquisitions.