In-housing Reserves with Planning Space

Over the past decade, Ithaca Energy has grown significantly into one of the UKCS’s leading independent oil and gas operators, supported by a series of major mergers and acquisitions and its initial public offering on the London Stock Exchange in November 2022. As the business expanded in scale and complexity, Ithaca recognised the need for a more integrated internal approach to reserves and resources management – one that would complement independent evaluations, strengthen governance, and provide clearer visibility across the full portfolio.

While the company continues to rely on independent evaluations from NSAI to support the Competent Person’s Report (CPR) required by Shareholders and Reserve Based Lending (RBL) banks, a strategic decision was taken to build an internal reserves process alongside these external assessments. This provides a stronger foundation for portfolio management, improves alignment with business planning assumptions, and supports more consistent, auditable decision-making across the organisation.

Reserves remain one of the most important performance indicators for an oil and gas company, underpinning valuation, investment decisions, financing arrangements and long-term sustainability. Ithaca’s internal process was therefore designed to capture the full portfolio of discovered opportunities, quantify uncertainty, improve traceability, and establish a structured framework for assurance, approval and auditability of reserves estimates.

A key enabler of this transformation was the selection of Quorum’s Planning Space suite as the foundation for an integrated reserves and business planning platform. Having already used Quorum applications within the business planning workflow, Ithaca identified an opportunity to replace legacy tools and create a seamless connection between reserves evaluation, economic modelling and corporate planning. This integration improves data governance, reduces manual intervention, enhances traceability, and ensures consistency between reserves and business planning datasets.

This presentation outlines Ithaca’s journey to establish its internal reserves process, including the drivers for change, development of the governing process, implementation of the supporting database and systems, and the benefits realised through integration with business planning. The session will also explore how a growing operator can build a reserves framework that strengthens decision-making, supports external assurance requirements, and provides a trusted foundation for portfolio management and future growth.

Speaker:

Shona Corbett, Portfolio & Corporate Reserves Lead, Ithaca Energy

Biography:

Shona Corbett is Corporate Reserves and Portfolio Lead at Ithaca Energy, with over 15 years of experience in the UK oil and gas industry. A reservoir engineer by background, she has held a variety of technical, operational, business planning and corporate roles throughout her career. Shona began her career with Chevron before joining Ithaca Energy following the acquisition of Chevron's UK North Sea assets. She has been closely involved in several transformational milestones in Ithaca's growth, including the company's IPO and multiple acquisitions and integration activities.

In her current role, Shona leads Ithaca's reserves and resources activities and supports portfolio management, business planning and strategic decision-making across the organisation. She is responsible for reserves assurance, the technical aspects of Ithaca's reserves-based lending process, and subsurface data management initiatives, and is a member of the Subsurface Leadership Team. Shona holds a BSc (Hons) in Mathematics from the University of Edinburgh and an MSc in Petroleum Engineering from Heriot-Watt University