Come join us for another interesting Distinguished Lecture on a topic important to everyone in the upstream oil and gas community.  This was one of the top picks, chosen by SPE-Alaska members, out of 20+ topics for the 2026/2027 Distinguished Lecturer series.  Please come out and support the local chapter.  All proceeds go toward SPE-Alaska scholarships.

The Subsurface Secret to Optimized Well Abandonment
Ruth Thomas
Well-Safe Solutions

Abstract:
The fundamental principles of zone permeability, fluid content, formation
pressure (including reservoir recharge prediction), and caprock integrity underpin
subsurface isolation requirements and drive decisions regarding abandonment
barrier placement. A comprehensive understanding of these elements is
essential, as they not only shape the overall well abandonment design but also
ensure that well duty holders remain compliant with regulatory requirements for
long-term containment integrity.
As a subsurface community, we are highly skilled in quantifying the subsurface
for exploration, appraisal, and development drilling, with a strong emphasis on
reservoir-level characterisation. However, well abandonment presents a unique
set of technical and operational challenges that require a shift in both mindset
and approach. How do we define key isolation parameters when data is limited,
particularly in the overburden? With aging well infrastructure, what happens
when a seemingly “perfect-on-paper” abandonment plan proves unworkable in
practice? What are the cost implications and where do the most significant
optimisation opportunities lie?
Through a series of case studies demonstrating collaboration between
subsurface specialists, well engineers, and Operators, this presentation will
showcase industry best practice for developing a robust subsurface basis of
design for abandonment. By addressing specific subsurface and engineering
challenges encountered in well abandonment projects, it will provide insights into
effective decision-making and risk-mitigation strategies and illustrate the benefits
of engaging a subsurface team throughout the entire well abandonment process,
from project conception through to execution.
What is the one idea you would like the members to take away from this
lecture?
By embracing a data-driven, risk-based approach to well abandonment, we can
shift the industry’s mindset from reactive problem-solving to proactive planning -
ensuring that subsurface expertise plays a central role in shaping the future of
well decommissioning.
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Biography:
Ruth Thomas is a geoscientist with 24 years’ experience in delivering subsurface
projects for operators such as CNR International, Apache, Talisman Energy, and
Repsol Sinopec. She holds a first-class Bachelor of Engineering honours degree
in Industrial Geology; an MSc in Geology, and after earning her MSc in
Decommissioning from the University of Aberdeen in 2022, she joined Well-Safe
Solutions as their Subsurface Manager, responsible for the company’s global
subsurface portfolio.
Ruth is a strong advocate for the role of geoscience in cost-effective well
abandonment, and she actively promotes technical excellence and industry best
practice through regular regulator and industry engagement, conference
presentations, and training initiatives. She is an active board member of the SPE
P&A Technical Section, and co-founder and current chair of the Offshore
Energies (UK) Geoscience Excellence in Decommissioning workgroup.