Management of Microbiologically Influenced Corrosion in Risk Based Inspection Analysis

Abstract

Abstract Operating offshore oil and gas production facilities is often associated with high risk. In order to manage the risk, operators commonly use aids to support decision making in the establishment of a maintenance and inspection strategy. Risk Based Inspection (RBI) analysis is widely used in the offshore industry as a means to justify the inspection strategy adopted. The RBI analysis is a decision-making technique that enables asset managers to identify the risk related to failure of their most critical systems and components, with an effect on safety, environmental and business related issues. Risk is a measure of possible loss or injury, and is expressed as the combination of the incident probability and its consequences. A component may have several associated risk levels depending on the different consequences of failure and the different probabilities of those failures occurring. Microbiologically Influenced Corrosion (MIC) is a degradation mechanism that has received increased attention from corrosion engineers and asset operators in the past decades. In this paper, the most recent models that have been developed in order to assess the impact of MIC on asset integrity will be presented and discussed. From a risk perspective, MIC is not satisfactorily assessed by the current models and the models lack a proper view of the MIC threat. Therefore, a review of known parameters that affect MIC is presented. The mapping and identification of parameters is based on the review of past models and an extensive up-to date literature study. The parameters are discussed and subsequently combined in a novel procedure that allows assessment of MIC in a RBI analysis. The procedure is sub-divided into one screening step and a detailed assessment, which fits the recommended approach to assess risk in a RBI analysis. To illustrate the practical application of the developed procedure a field case is presented.