Towards the Formal Reliability Analysis of Oil and Gas Pipelines

It is customary to assess the reliability of underground oil and gas pipelines in the presence of excessive loading and corrosion effects to ensure a leak-free transport of hazardous materials. The main idea behind this reliability analysis is to model the given pipeline system as a Reliability Block Diagram (RBD) of segments such that the reliability of an individual pipeline segment can be represented by a random variable. Traditionally, computer simulation is used to perform this reliability analysis but it provides approximate results and requires an enormous amount of CPU time for attaining reasonable estimates. Due to its approximate nature, simulation is not very suitable for analyzing safety-critical systems like oil and gas pipelines, where even minor analysis flaws may result in catastrophic consequences. As an accurate alternative, we propose to use a higher-order-logic theorem prover (HOL) for the reliability analysis of pipelines. As a first step towards this idea, this paper provides a higher-order-logic formalization of reliability and the series RBD using the HOL theorem prover. For illustration, we present the formal analysis of a simple pipeline that can be modeled as a series RBD of segments with exponentially distributed failure times.Comment: 15 page

On safety of critical infrastructures modeling with application to port oil transportation system

A new approach to safety investigations of multistate complex systems with dependent components at variable operation conditions called critical infrastructures is proposed. The safety function of the critical infrastructure system is defined and determined for an exemplary “m out of l” critical infrastructure. In the developed model, it is assumed that the system components have the multistate exponential safety functions with interdependent departures rates from the subsets of the safety states. The approach is adapted to safety prediction of oil piping transportation system operating at a maritime port