3.3 Risk factors and assessments

Risk assessments must be performed to verify that the facilities risk level is within acceptable limits in the period of life extension and As Low as Reasonably Practicable (ALARP). The principle of ALARP is in widespread use in the oil and gas industry. The following risk evaluations shall be performed based on the context defined for life extension:


Ensuring risks have been reduced to ALARP means balancing the risks against the costs to further reduce it. The decision is weighted in favor of health and safety because the presumption is that OGPs should implement the risk reduction measure. It is expected that the latest available technology and knowledge related to analysis of major accidents is applied. The conservatism level and any assumptions made in risk assessments are to be assessed and evaluated for all continuous operations. The vulnerability, actual and expected effectiveness of the barrier function, including technical, organizational and operational elements shall be included in the risk assessment.

The OGP risk matrix consists of a consequence axis and a likelihood axis. The consequences are those of credible scenarios (taking the prevailing circumstances into consideration) that can develop from the release of a hazard. The potential worst case consequences, rather than the actual ones (that may have occurred

Maintenance Management of Aging Oil and Gas Facilities DOI: http://dx.doi.org/10.5772/intechopen.82841


Figure 8. Typical risk matrix used by oil and gas producers (OGPs).

probability of failure (PoF) is generally employed for structures, pipelines, position mooring, and flexible or steel catenary risers etc. and requires string technical expertise and often specialist software packages. Qualitative assessments is also possible but must be supported by effective data management and operating his-

Risk assessments must be performed to verify that the facilities risk level is within acceptable limits in the period of life extension and As Low as Reasonably Practicable (ALARP). The principle of ALARP is in widespread use in the oil and gas industry. The following risk evaluations shall be performed based on the context

• Accumulation of Operational Risk Assessments (ORA), as some of which may be decoupled because they have been considered in isolation and not in

• Risk assessment of major accident risk, Quantitative/Qualitative Risk Analysis

Ensuring risks have been reduced to ALARP means balancing the risks against the costs to further reduce it. The decision is weighted in favor of health and safety because the presumption is that OGPs should implement the risk reduction measure. It is expected that the latest available technology and knowledge related to analysis of major accidents is applied. The conservatism level and any assumptions made in risk assessments are to be assessed and evaluated for all continuous operations. The vulnerability, actual and expected effectiveness of the barrier function, including technical, organizational and operational elements shall be included in the

The OGP risk matrix consists of a consequence axis and a likelihood axis. The consequences are those of credible scenarios (taking the prevailing circumstances into consideration) that can develop from the release of a hazard. The potential worst case consequences, rather than the actual ones (that may have occurred

combination, potentially resulting in unknown increased risks

• Occupational safety, health and working environment.

torical data to make good engineering assessments.

Recommended life extension assessments of barriers [5].

• Emergency preparedness and response

3.3 Risk factors and assessments

defined for life extension:

• External environment

(QRA)

Figure 7.

Maintenance Management

risk assessment.

68

previously), are used. After assessing the potential outcome, the likelihood on the vertical axis is determined on the basis of historical evidence or experience that such consequences have materialized within the industry, the entity or a smaller unit (Figure 8).

## 3.4 Maintenance management system

Effective inspection and maintenance are important in ensuring asset integrity and reliability. In developing the maintenance management systems an initial review is required determine status and how the aging processes is covered in the existing maintenance program. The review is to evaluate the need for updating the integrity, reliability, vulnerability and consequence analysis for continuous operations in the future. Experience and knowledge from documented failures and lessons learnt shall also be part of the evaluation and be used to improve the maintenance management system. In principle, the maintenance management system should be within a computerized database with detailed history of the operating, design, assessment, inspection and maintenance records accessible to all key personnel.
