Pipeline operators can incur significant penalties for having capacity shortfalls below firm contracts. It is insufficient to ensure that the pipeline can deliver contracts when all facilities are available; a design also needs to consider how the pipeline performance is impacted by planned and unplanned facility outages. As such, availability based design methodologies are becoming more important when designing pipelines.
Availability based design requires the hydraulics engineer(s) and the reliability engineer(s) to work in tandem to achieve the most cost effective pipeline design while considering all the potential outages and their mitigations. One of the most cost effective outage mitigation involves the use of linepack to maintain system requirements and delay the effect of system outage impacts. Determining the probabilistic benefit of linepack as a mitigation methodology can be a difficult and onerous task.
In order to incorporate linepack into availability based design, the hydraulics engineer needs to perform a transient analysis to determine the volume of linepack available for mitigating facility outages. Additionally, the linepack calculated in the transient model needs to be incorporated into a probabilistic outage model. This paper examines using a Monte Carlo simulation to determine the benefits of linepack as an outage mitigation methodology.