Reliability Analysis

‘Reliability Analysis’ involves a sequence of six phases that must be executed in order to qualify the suitability of well barriers to be established in a well. The results of a reliablity are used to develop procedures and practices to prevent barriers to be established in a well. The results of a reliability analysis are used to develop procedures and practices to prevent mitigate and /or predict faliure of barriers.

Phase 1: Define the Well Barrier System.

  • Define the specific Operation / Activity with procedures involved.
  • Compile a list of well barriers to the implemented for the Operation / Activity.Assign barriers / respectively for the primary and secondary envelopes.
  • Specify the Functional(s) of each well barrier.
  • Develop detailed Well Barrier Schematics with illustrations of all potential floe paths and the presence of a two barrier envelop for each.

Phase II: Identify Potential Modes of Barrier Failure.

  • Identify ALL Potential Modes of Failure for the barriers established for the specific Operation / Activity in Phase I.
  • Develop a ‘Root Cause’ Model for each Failure Mode.
  • Analyze and Outline the Potential Effects / Consequences that would occur as a result of failure.
  • Prepare a Failure Mode Analysis Model for All Barriers within the System (Failure Modes Effects & Criticality Analysis – FMECA).

Phase III: Construct a Reliability Model.

  • Utilize the Logic Gate System (AND Gate, OR Gate, etc) and develop a Fault Tree System such that different Root Causes are linked to the eventual modes of failure.
  • Prepare Methodologies to Prevent and Mitigate failures based on the Root Causes identified in Phase II.

Phase IV: Perform a Qualitative Analysis of the System.

  • Identify and categorize the modes of failure that are more likely to occur in specific well situations.
  • Prioritize the Modes of Failure on the basis of Severity of their Consequences.
  • Develop Practical Strategies that can be implemented to prevent and mitigate the potential failures in a System.

Phase V: Perform a Quantitative Analysis of the System.

  • Estimate of the Failure Probabilities of every Barrier in the System.
  • Estimate the Varying Rates of Failure for every Barrier.
  • Determine the Expected Time for every Barrier to experience its First Failure.
  • Determine the Frequency of Failure of every Barrier.

The Expected Time for the First Failure of a Barrier is a critical parameter in Engineering Reliability. This is due to the behavior / nature of barriers wherein if a failure has occurred once, then the possibilities of the failure recurring a second time are more.

Therefore, after the first failure of a barrier, the Frequency of Barrier Failure also becomes a critical parameter in a Reliability Analysis.

Phase VI: Prepare an Official Report.

  • Compile and Document a Barrier’s Progress till Date, Current Status and Future Expectations.
  • Any and All Limitations of a Barrier must be highlighted.
  • The Report must include practical recommendations for Re-Planning or Re-Designing individual barriers or the complete system as a whole.
  • Modifications to the existing Operational Procedures and Practices towards improving Integrity management must also be included.
Report 6 1 Define 2 Identify Quantitative Study 5 3 Construct Qualitative Study 4