Quantitative Risk Assessments

Approach

ExproSoft has a strong focus on quantitative risk assessments (QRAs) and reliability improvement issues for well systems, subsea production systems and drilling/intervention technology. Applied studies are performed by a multidisciplinary team of experienced engineers with a practical approach and strong analytical competence. The company offers these services through staff members with more than 20 years experience from various oil-field risk assessments and reliability studies. In addition, ExproSoft has a broad network of contacts within the research community at SINTEF and the University of Science and Technology (NTNU) in Trondheim (Norway), forming a platform of world-class risk and reliability engineering expertise.

Methodology

QRAs are based on the use of recognized reliability methods (FMECA, CCA, ETA, FTA , Markov theory, etc). Concerning fault tree analysis, we are using CARA FaultTree from Sydvest. The WellmasterTM database  is an indispensable tool for risk and reliability assessment of well concepts. This database is currently in its 5th round of updating and is currently supported by 12 major oil companies worldwide. The database holds valuable data on operational histories with detailed reliability data from a large number of production and injection wells. SubseaMaster is a similar concept for subsea production systems, which was initially launched jointly by ExproSoft and Petrobras. SubseaMaster Phase II was completed as a joint industry project in June 2003, with Phase III scheduled for kick-off in April 2004.
ExproSoft applications of reliability data and reliability engineering methods over the last years include:

· Risk and reliability studies
· Lifecycle cost/profit (LCC/LCP) analysis
· Tender evaluations and purchasing decisions
· Rig contracting strategies
· Incentive based contract definitions
· Test/qualification programs
· Independent system design reviews
· Design improvements
· Downhole barrier acceptance criteria definitions
· Concept evaluation and comparison

Benefits

Benefits, which can be attributed, to risk and reliability analysis are:

· Improved lifetimes of downhole equipment with reduced
  intervention requirements
· Reduced requirements for surface safety systems resulting from
  improvements of downhole barriers
· Independent design reviews and reliability verifications, with cost
  savings through reduced equipment failure rate in service
· Development of new, flexible standard for acceptance criteria and
  operational testing of downhole safety valves
· Decision support for selection of downhole and subsea systems

The most profiled cost saving case is a study in Norway where a risk analysis applying updated data on reliability of downhole safety valves demonstrated that an acceptable safety level (blowout escalation risk) could be achieved through a production riser design which eliminated the need for passive fire protection. This led to a cost saving of some NOK 720 million (ca USD 81 million) for the Heidrun field Tension Leg Platform (TLP) when compared to the Snorre TLP – a development which was completed a few years earlier with use of passive fire protection on the risers. Without the availability of updated and recognized, independent SCSSV reliability data this cost saving would not have been achieved

Case studies

ExproSoft staff members and co-operation partners have been involved in more than 200 studies worldwide over the last decade involving downhole and/or subsea oil/gas production systems’ risk and reliability issues. You can review selected case studies/project on the right hand side of our website. Please contact us at exprosoftexprosoft.com for further information or quotations on risk/reliability studies.