Subsea System Engineering and Operations Consulting

Developing an “Actively Managed” Subsea Asset Intervention Strategy

Written by: Brian Saucier : President, DeepMar Consulting


This blog shares  key learning’s for engineering and operational teams to consider when building a successful subsea asset production & intervention strategy.   Early identification of design opportunities to enhance safety, reliability and efficiency for subsea field optimization is essential.   This concept is demonstrated in the simple INFLUENCE DIAGRAM (ref Figure 1 )  .   Often many design opportunities are missed which could, implemented result in improved Life of Project  value and reduction of risks.  During project sanction, increased awareness of future intervention & abandonment operations should be incorporated and considered within the design basis.   Information within the blog could be a reference tool to both intervention and asset managers who are continuously monitoring many of the parameters in order to achieve maximum ROI within a dynamic oil and gas price environment.


Development of oil and gas fields employing subsea technology results in a higher cost of intervention as opposed to surface well or offshore platform well location.  Subsea projects carry an economic liability both in management of production optimization, using high cost assets to intervene, and future Plug and Abandonment liability which can erode overall project ROI if not adequately managed.

Creating and maintaining a “Active Managed” subsea intervention strategy is essential to manage field economics, technology changes and production contingencies. Subsea assets must have a flexible Intervention strategic plan to forecast “life of field” intervention cost and ensure specialized equipment and technology gaps for future intervention requirements are met. With the lower price environment, the need to focus on how to manage existing assets and to reap optimized returns (eg added value) while maintaining lower cost and risk offers tremendous opportunity.


  • Subsea Interventions are inevitable, and should be fully planned and incorporated within every phase of the Subsea development design phase.  Projects should adequately simulate via probability modelling, a range of dynamic parameters, intervention types and be an integral service component to the subsea asset team
  • Information gained from continuous surveillance and influence changing parameters should be seamlessly integrated between intervention engineering and production asset team.
  • Given the limited published industry data related to subsea component reliability, the need to create “live” database resource files to track regional component failure rates and trends
  • Front end design decisions should integrate subsea intervention requirements into subsea production equipment design to enable production optimization and lower risks when performing future intervention operations.  Intervention failure rates, frequency and types of intervention operations shall be integral to the decision as to whether a Horizontal or Vertical tree is selected.
  • Lower cost intervention vessels verse typical MODUs, offer a suite of intervention operations which can be performed and should be considered and be a factor in the economic model.
  • Setting realistic expectations on intervention frequency, types of operations and risk in a dynamic oil and gas price environment should be continuously monitored and managed.
  • Forecasting specialized tooling and identification of intervention assets to capitalize on market price cycles should be constantly monitored to reduce cycle time for intervention readiness.   Consider investment in intervention readiness when price is low to be able to reduce intervention cycle time when market shifts to higher price.
  • Improve wellbore design by engagement with intervention specialists to evaluate intervention tool compatibility and risks on the front end to avoid identification of an enhancement during the intervention planning engineering – which is too late.
  • Enhance subsea assets to allow intervention access points and offer opportunities which can be explored using lower cost intervention vessels.
  • Develop Plug and Abandonment strategies during field life to capitalize on lower price market cycles and development of core lower cost enabling technology to be realized.
  • Improve competency and training to ensure tools, equipment and processes are well defined and functional and structural performance limits defined.
  • Build appropriate simulation models to cover the range of “realistic uncertainty” within the life of field development plan.


  • During the economic sanction and evaluation of the intervention strategy, the team should focus on creating “realistic simulations” which can be processed within deterministic and probability models simulating a range of uncertainty in both positive and negative directions.  Selected dynamic parameters which should be included in Intervention Strategy include:
o   Deviations in oil and gas price environment
o   Technology and/or Process improvement enablers
o   Improved Reliability thru enhanced design assurance and Root cause analysis
o   Data Acquisition systems to manage maintenance and lowering of downtime risks
o   Execute Verification and Validation process
o   Identification of “all” Liabilities – PA, Well Control / Well containment
o   Equipment (over-supply or under supply conditions)
o   Leverage Contractor strategies and share risks (where possible)
o   Regional vessel /MODU market conditions
o   Knowledge and application of operations to meet regional regulatory requirements


  • Incorporate Intervention input within the design of lower and upper completion.   Focused on tubing isolation barriers, casing & tubing selection, auxiliary component selection, bore size compatibility with specialized fishing and logging tools, future re-completion or repair activities, etc.  Often opportunities are missed during the initial design phase resulting in greater completion risks, higher cost and/ or potential loss of well.


  • Maintaining production and intervention readiness metrics, acceptance standards and KPI’s to ensure all teams are aligned and focused on optimization and opportunity recognition. Such include established alignment of intervention operations sequences to ensure well shut in times are optimized with multiple trip, cost saving solutions and operational methods.


  • Equipment verification and validation plan to improve reliability, integrity and safety. Enhance component performance through rigorous verification and validation especially on tools which are rental and limited performance history is known.  Details to enhance the overall reliability of components and processes to ensure that operational conditions do not expose equipment to subsequent failures are:
o   Established Load case definition and performance application
o   Testing and qualification simulation to be aligned with operational conditions
o   Standardized interfaces and methods with continuous improvement on learning


  • Partnerships and contracting strategy to lower cost, improve efficiency and enhance cycle time readiness.    Partners become familiar with E&P operators risk profile and methods by which work in conducted.   This knowledge improves over time and leveraging aligned expectations and bridging of safety cultures aid in overall learning curve efficiency enhancements.


  • Identification of transitional points within the field development process such as (field architecture, well intervention flexibility incorporation into completion, subsea tree selection) are a few of the key focus items. Ability to influence or “refine” the design diminishes over time, while the cost of change and schedule increases exponentially over time.   Successful project teams recognize the point of inflection where teams work towards brainstorming optimized solutions yet transition to converge to decision and build appropriate focus and execution strategy to manage risks and deliver the project.   Realization of this ‘inflection point” is a key transition towards maturing the concept with additional engineering evaluation.  (Figure 1)

Figure 1: Typical Influence Diagram


Closing Comment  

Management of subsea assets involves the work and coordination of many multi-disciplined teams.  Coordination of the teams and communication via a “dynamic” Intervention strategy for the field which keeps focus and awareness of the opportunities is one of the keys to success.  Several of the recommendations offered in this paper were a result of many years of experience and observations noted.  DeepMar can assist your team in various aspects both strategic and tactical to deliver a managed plan resulting in a low cost more optimized solution.

Brian Saucier – DeepMar Consulting

Brian is an independent consultant with over 33 years of industry experience specializing in deep water subsea project design, installation and life of field intervention. He has consulted for several of the major E&P companies in various project roles.  Brian is a member of ASME and has authored and co-authored several industry papers in the field of subsea engineering and patent holder.  Brian can be reached at




  1. August 23, 2016    

    Comments ?

  2. Joe Scranton P.E. Joe Scranton P.E.
    October 12, 2016    

    Thanks for an insightful and thought provoking article on Intervention Strategy. I think sometimes folks tend to get overwhelmed when thinking about a problem like “Intervention Strategy” especially before you even complete the drilling program. In my mind the (early lifecycle) goal for the Intervention strategy should be to stay at a high level and keep away from too many “cool widgets”.

    If the team maintains a 10,000 ft. perspective to the intervention challenge, such as applying proven approaches, looking for technology gaps, and in this manner using existing building blocks wherever possible in order to minimize risk, cost, and maximizing availability, they can be assured of tangible results within a short period of time with this worthwhile exercise.

    Regards, Joe Scranton P.E.

    • Brian Saucier Brian Saucier
      October 15, 2016    

      Thank you Joe, appreciate your feedback. Establishing the proper “elevation perspective” is a great point. Regards, Brian

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…In addition to Brian’s superior technical acumen, he has an excellent understanding of the financial implications of technical decisions. I highly recommend Mr. Saucier for any assignment he may pursue in the oil & gas arena….
Allan C. BrunsBusiness Development Consultant