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Successful seminar on wellhead fatigue

On 6 December 2012, the Petroleum Safety Authority Norway (PSA) conducted a seminar on wellhead fatigue in a system perspective.

The goal of the seminar was to increase general knowledge on issues related to wellhead fatigue for subsea facilities, as well as to share experiences in the industry. The main focus was on a system and big picture mindset from the drilling facility via the drilling riser to the subsea facility and down into the well.

The PSA, DNV, Shell, OLBRI, FMC, NeoDrill, GE Oil & Gas, Statoil and BP (4Subsea) delivered nine presentations, giving the around 150 participants a status update on wellhead fatigue. The presentations covered the following topics:

  • Joint Industry Projects (JIP) and other cooperation projects.
  • International experiences.
  • Documentation, verification and analyses.
  • Instrumentation and monitoring.
  • System for integrity management.
  • Improvement measures and solutions.
  • Safety factors and uncertainties.
  • Sensitivity assessment of input parameters.
  • Wellhead fatigue - past, present and future.

Challenges relating to wellhead fatigue comprise everything from the intervention facility, required intervention equipment, subsea templates with associated equipment, and the well itself.

System approach
One cannot look at single components in isolation. Instead of focusing solely on the wellhead, it is necessary to take the whole system into account. In many cases, the solution may lie in other parts of the system. A system approach ensures management of the interface between standards and norms and makes sure that all relevant parties are involved.

On our way
As part of the cooperation project, and in the individual companies, much work has been performed on issues relating to wellhead fatigue. So far, much of this work consists of theoretical analyses and estimations that have not been verified against actual loads.

Some work is still outstanding in terms of providing facilities with instrumentation equipment for monitoring and registering conditions and parameters that may be significant for verifying results. This is a prerequisite for being able to perform detailed analyses and calculations to document compliance with regulatory and company-specific requirements. In case of uncertainty, it is necessary to compensate with corresponding safety margins to satisfy the requirements.

Need for coordination
The seminar showed that much work is ongoing in several companies. However, coordination is necessary to share this experience. The challenge is to gather all the knowledge and apply it to ensure development and continuous improvement.

See the right-hand margin to download the presentations from the seminar (PDF).

Contact person, PSA:
Trond E. Sundby, e-mail: Trond-e.sundby@ptil.no