Abstract

The perception of shallow gas accumulations has changed from one of ‘drilling hazards’ to ‘potential resources’ over the last few decades. The Paso Anomaly, identified on seismic at a depth of ~550m  TVDSS, is a high-amplitude reflector which exists in the shallow overburden of the Catcher Field Area  in the Central North Sea. This anomaly has previously been avoided during drilling as it could host gas. Via seismic based characterisation, this work interprets the depositional environment of the anomalously high reservoirs as glaciogenic. AVO analysis demonstrated a class III response, indicative  of gas. The gas was interpreted to be biogenically altered thermogenic gas which has migrated from  depth due to faulting, associated with Zechstein diapirism. Regional mapping supports a Lower  Pleistocene aged deposit, with the deposit comprising two units; a Lower Unit that includes MegaScale-Glacial-Lineations, De Geer moraines and an esker, and an Upper Unit that comprises a sandur  plain. These deposits are interpreted to be the depositional record of an advance followed by retreat  of an ice-stream on the eastern edge of the British and Irish Ice Sheet into the Central North Sea and has implications for the timing of arrival of Lower Pleistocene ice into Central North Sea.

Seismic 2024, P&J Live, Aberdeen 1st – 2nd May 2024

Seismic 2024 will cover the role of geophysics in the energy lifecycle from exploration, appraisal, development and production through to decommissioning and repurposing. The event will explore how seismic sustainably supports the UK’s energy security and Net Zero obligations, and will aim to include hydrocarbons, renewables such as offshore wind and geothermal, carbon storage and advancing technologies in the seismic space. Tickets are available here. (https://www.spe-aberdeen.org/events/seismic-2024#tickets)

Make sure to catch Jack or our Head of Geophysics Michael Braim at Seismic 2024 to find out more about ERCE’s petrophysical and geophysical capabilities.

Jack McLoughlin

Jack is a Graduate Petrophysicist whom joined the company in September 2023, after finishing his postgraduate studies. He holds a BSc in Geology at the University of Edinburgh and most recently, an MSc in Petroleum Geoscience at the University of Aberedeen. Having been awarded a scholarship from Harbour Energy for his studies in Aberdeen, Jack undertook his final project with the company and graduated with distinction. Since joining, Jack has engaged in a variety of specialist petrophysical studies such as fault seal analysis, low resistivity pay and well screening for CCUS, as well as involvement in Competent Person’s Reports and Reserves and Resource auditing.

To date, Jack has gained experience in the interpretation of clastic, carbonate and fractured basement reservoirs for a variety of applications. These range from traditional oil and gas exploration and development, CCUS, Lithium extraction and geothermal. These projects have spanned a diverse range of locations, including the Norwegian and UK North Sea, Middle East, Southeast Asia and South America. He is an active member of the Geoscience Energy Society of Great Britian and the London Petrophysical Society.

Michael Braim