Ruth Thomas
Subsurface Manager, Well-Safe Solutions
Module: Well Plug and Abandonment: Subsurface and Well Engineering
Biography
Ruth Thomas is a Subsurface Manager at Well-Safe Solutions, specializing in well plug and abandonment (P&A) operations for offshore decommissioning. She leads the module Wells P&A, offering learners comprehensive insights into the technical, regulatory, and operational aspects of permanently abandoning offshore wells.
With extensive experience in well integrity, barrier design, and P&A execution, Ruth has been instrumental in delivering safe and compliant well abandonment programmes across the North Sea. Her expertise spans well assessment, regulatory engagement with bodies such as OPRED, and the management of complex P&A campaigns involving high-pressure high-temperature (HPHT) wells and legacy assets.
Ruth’s approach combines technical rigour with practical problem-solving, ensuring that learners understand both the engineering fundamentals and the operational realities of well abandonment. Her contribution to this programme equips participants with the knowledge required to navigate the challenges of well P&A, from planning and barrier design through to final regulatory sign-off.
Experience & Expertise
- Subsurface Manager at Well-Safe Solutions
- Specialist in well plug and abandonment (P&A) operations
- Extensive experience in well integrity and barrier design
- P&A execution across the North Sea
- Well assessment and regulatory engagement with OPRED
- Management of complex P&A campaigns including HPHT wells
- Legacy asset well abandonment specialist
- Expert in planning and barrier design through to final regulatory sign-off
- Technical rigour combined with practical problem-solving
Training Course Module | Subsurface and Well Plug and Abandonment Fundamentals
Ruth Thomas delivers the Lean Decom training course module, ‘Subsurface and Well Plug and Abandonment‘. In this module, she provides a comprehensive walkthrough of the fundamental principles of wells and the subsurface, outlining the decision context required to determine what needs to be isolated underground and how to achieve it effectively.
Ruth covers critical metrics like sustained flow potential and the minimum safe abandonment depth to ensure long term containment. She also explains the subsurface basis of design for abandonment and the creation of plumbing diagrams that marry geology with well architecture.
Ruth shares professional guidance on the stages of physical abandonment, specifically reservoir isolation, intermediate zone isolation, and wellhead recovery, while advocating for a risk approach based on the ‘As Low As Reasonably Practicable’ (ALARP) principle and achieving efficiency gains through effective subsurface planning.
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