Isla Stewart
Isla is an Associate in the Oil & Gas team. She qualified in 2010 after spending her traineeship with a leading international law firm. Isla then spent three years with the offshore oil and gas industry's leading trade association, Oil & Gas UK, as their in-house lawyer where she gained a strong background in working on complex industry issues across the UKCS.
Isla advises both operator and service sector clients on a range of aspects including asset acquisitions and disposals, joint venture matters and service sector contracts.
She has also been involved in a number of industry initiatives, most prominently the revision of the LOGIC general terms and conditions, the competing interests of the renewables industry offshore and the development of post-tax security for decommissioning security agreements.
Isla has also spent time on secondment to upstream oil and gas companies Talisman-Sinopec and Maersk Oil.
Practice Area
Panel
- Consulting Editorial Board
Qualified Year
- 2010
Membership
- Law Society of Scotland
Education
- LLB, University of Edinburgh and Diploma in Legal Practice, University of Edinburgh
5 Contributions by Isla Stewart
PRACTICE NOTES
Decommissioning offshore installations and pipelines: international law (UNCLOS, OSPAR, London Convention) and UK government policy, including OSPAR Decision 98/3 derogations and DESNZ guidance
Oversight of UK decommissioning policy and its delivery sits with the Department for Energy Security and Net Zero (DESNZ). Formed on 7 February 2023, DESNZ assumed the energy remit of the former Department for Business, Energy and Industrial Strategy (BEIS), which has now been dissolved, including its responsibilities for decommissioning. Any mention of ‘BEIS’ in this practice note refers to the department’s former functions. Although the UK issues policy documents, a substantial portion of the regime is driven by the UK’s commitments under international law.
International Law—installations
The 1958 Geneva Convention on the Continental Shelf (Geneva Convention) was the first treaty to set out the law of the sea, and it remains the only convention that expressly mentions the ‘removal’ of installations. The United Kingdom gave effect to the Convention domestically in 1964 through the Continental Shelf Act 1964 (CSA 1964), which vested in the Crown all rights exercisable in designated areas beyond territorial waters concerning the seabed and subsoil in those zones. Today, two core international conventions govern the decommissioning of installations in the UK:
The United Nations Convention on the Law of the Sea 1982 (UNCLOS)—widely recognised as customary international law...
Energy
PRACTICE NOTES
LOGIC’s IMHH for UKCS and Offshore Renewables: Mutual Hold Harmless Regime—Scope, Exclusions, Waivers, Signatories and Duration (2022–2031)
Introduction
The Industry Mutual Hold Harmless Scheme (IMHH) was launched in 2002 after a thorough cross-industry consultation, coordinated by Leading Oil and Gas Industry Competitiveness (LOGIC). Its aim was to bridge the ‘contractual gap’ between contractors where the LOGIC Standard Conditions of Contract (the “LOGIC Standard Conditions”)—or other agreements using a ‘small family’ indemnity regime (see below)—were applied. The LOGIC Standard Conditions are standard-form contract terms issued by LOGIC, originally created to cover the lifecycle of oil and gas activities, including onshore and offshore services, well services and construction. They are now also employed for offshore renewable energy projects, for example the construction and/or maintenance of offshore wind farms (together with related transmission infrastructure), as well as the construction and maintenance of electricity interconnectors. The IMHH framework is likewise commonly used on offshore projects where newly constructed assets are located near existing infrastructure and the respective owners of those infrastructures enter into Crossing Agreements...
Energy
PRACTICE NOTES
UK offshore oil and gas decommissioning: statutory framework and section 29 Petroleum Act notices for wells, installations and pipelines; NSTA/OPRED roles, financial assurance and CCUS Change of Use Relief
The Petroleum Act 1998 (PA 1998) empowers the Secretary of State (SoS) to issue licences to companies, permitting them to explore, drill for and recover petroleum, under the oversight and direction of the North Sea Transition Authority (NSTA) (previously called the Oil & Gas Authority) (see Practice Notes: Oil & Gas—UKCS licensing regime and North Sea Transition Authority (NSTA) for further background). Decommissioning, by contrast, is overseen by the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED), within the Department for Energy Security and Net Zero (DESNZ), working in consultation with the NSTA as necessary. Up to 14 July 2016, the government department in charge of energy policy was the Department of Energy and Climate Change (DECC). From 14 July 2016, DECC was folded into the Department for Business, Energy and Industrial Strategy (BEIS). On 7 February 2023, the Department for Energy Security and Net Zero (DESNZ) was created and assumed the energy remit of the former BEIS, which no longer exists. Mentions of ‘BEIS’ and ‘DECC’ in this practice note refer to the former functions of those departments.
What are the legislative rules on oil and gas well decommissioning?
The Licence regulates the relationship between the Licensee and the...
Energy
PRACTICE NOTES
UK offshore oil and gas installations and pipelines: DESNZ/NSTA decommissioning programme process—preparation, consultation, approval, fees, derogations and enforcement under the Petroleum Act 1998
By design, offshore oil and gas decommissioning programmes are intricate pieces of work. They demand collaboration across every department within the organisations proposing the programme, together with close engagement with the Department for Energy Security and Net Zero (DESNZ), the North Sea Transition Authority (NSTA) (previously the Oil & Gas Authority), and the support of a range of stakeholders. DESNZ was created on 7 February 2023 and assumed the energy brief of the former Department for Business, Energy and Industrial Strategy (BEIS), which has now been wound up. Any mention of ‘BEIS’ in this practice note refers to BEIS’s former functions. The rights and duties connected to decommissioning programmes sit in Part IV of the Petroleum Act 1998 (PA 1998). That said, PA 1998 largely supplies the framework and procedures, while most practical detail about decommissioning programmes appears in the Guidance Notes on Decommissioning of Offshore Oil and Gas Installations and Pipelines under the Petroleum Act 1998 (the Guidance Notes). Despite the guidance, the need to interact with DESNZ, alongside consultation obligations, ensures every decommissioning programme is tailored. In practice, engagement and consultation shape outcomes, so no two programmes are the same, despite the common legal framework.
Timing of decommissioning...
Energy
PRACTICE NOTES
UKCS oil and gas asset transfers: LOGIC Master Deed—pre-emption, standardised transfer arrangements, Execution Deeds drafting, Master Deed Online and NSTA consents
The Master Deed is the standardised mechanism used across the United Kingdom Continental Shelf (UKCS) to formalise asset transfers. It is long-established and addresses two strands: (i) pre-emption, and (ii) standardised transfer arrangements. Its four principal objectives are to:
bring existing pre-emption provisions into a common form
provide pro-forma transfer arrangements
cut complexity around document execution, and
deliver greater certainty over completion timing
Structure
The concept is embedded in the main body of the Master Deed, but most day-to-day operative provisions sit in the schedules, arranged as follows:
main body — appoints the Administrator to operate the Master Deed processes and provides for new parties to join via a Deed of Adherence
schedule 1 — lists the Contracting Parties at the date of signature
schedule 2 — New Transfer Arrangements — whose Annexes include the Execution Deed
schedule 3 — New Pre-Emption Arrangements, and
schedule 4 — Deed of Adherence
The Administrator
Run by an Administrator appointed under Clause 5, the process is undertaken by UKCS Administrator Limited (a subsidiary of LOGIC)...
Energy
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