Unitisation and equity determination

RPS offers unbiased and independent advice on industry standards for the oil and gas sector. RPS is known for its deep expertise, whether acting as an independent expert during dispute resolution procedures, or providing strategic advisory and technical support services to companies involved in unitisation and redetermination processes.

Over 30 years of experience on field unitisation and redetermination projects

Field unitisation or redetermination projects can be challenging for even the more experienced upstream E&P technical professionals. They differ significantly from other field studies in the intensity with which the results will be scrutinised by competing stakeholders and the degree of interdisciplinary integration required to withstand such critical examination and deliver a safe result that all Parties can accept.  This requires specialist knowledge of what is expected, a clear understanding of position and role within process, and how best to approach the work.

RPS has been engaged to resolve disputes relating to hydrocarbon ownership on more occasions than any other consulting firm in the world.

Since 1986, we’ve been sharing our expertise and experience in pre-unitisation and equity redetermination with large multi-national companies seeking advice to verify that they have developed an optimum techno-commercial model that complies with all the necessary procedures; smaller companies which don't have the expertise and in-house resources to properly protect their own interests; and law firms on preparing process and procedures within operating agreements.

Our teams have deep expertise in delivering projects within oil and gas fields around the world, across 6 continents including Europe, Africa, Asia, Australia and North & South America.




Our experience

global unitisation and equity (re)determination projects
as Expert
as Advisor
years of delivering unbiased and independent advice

RPS unitisation and redetermination experience

Ian Linnett


Ian leads the RPS redetermination and unitisation services team. Over a career spanning 38 years, he has provided technical and strategic advice to clients in this specialised area with particular focus in reservoir modelling, volumetric analysis and project management. He is equally comfortable managing the Independent Expert role, or providing strategic advisory and technical support services to companies involved in unitisation and redetermination processes. During this work, Ian has been involved with drafting numerous technical procedures for inclusion in Unit Operating Agreements and has represented clients on both unitisation and equity redetermination technical committees.

Ian has delivered over 50 unitisation and equity redetermination projects for companies involved in hydrocarbon ownership disputes – in the North Sea including UK, Norway, Netherlands, and internationally in North Africa, SE Asia, North and South America and Australia. Much of this work has been technically focused but he has also been exposed to the commercial and legal issues in a number of projects, including his appointment as part of a dedicated team as a court-appointed Expert in the Dutch North Sea Logger Field of 2003.





Oil & gas field unitisation and redetermination – a practical workshop

RPS offers a two to five-day workshop which provides valuable insight into unitisation and equity redetermination principles, international practices and field examples, topics include:

  • Terminology, definitions and concepts: - achieving a common understanding and sources of information
  • Unitisation and redetermination examples - North Sea and international
  • Approaches and alternatives to unitisation - fixed, deemed and temporary tract participation; asset swaps and licence harmonisation
  • Choosing an appropriate technical 'Basis of Determination' - static models, weighting factors, recovery-based approaches, the pros and cons
  • understanding the strengths and weaknesses of redetermination practices
    • Timing in relation to field development - pros and cons of traditional vs key step procedures
    • Operator’s and partners’ obligations and opportunities - dispute resolution mechanisms; the role of Expert and the pros and cons of pendulum approaches; legal issues
  • Drafting required agreements: U(U)OA; redetermination procedures - the AIPN Model Form Agreement
  • Undertaking equity protection projects: sensitivity studies; techniques to meet strategies; presenting to an Expert
  • Outcomes of redetermination - production and cost rebalancing

Exercises and discussions are included, and modified examples which are steered towards topics of interest to the participants. 

Time is set aside to address specific problems participants may choose to bring along. This can involve interactive team work on a specific field case making this workshop ideal as an interdisciplinary project kick-off activity.

Workshop brochure

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