Technical Presentations at the January 2017 Meeting

1.1  ‘A New Risk-based Method for Assessing Microbiological Induced Corrosion’, Matin Momeni, DNV-GL

Establishing a maintenance and inspection strategy is a key step in offshore oil and gas production facilities management. Risk Based Inspection (RBI) analysis is the best approach to facilitate maintenance and inspection in the offshore industry. From a risk prospective, MIC is not satisfactory assessed by the current models and the models lack a proper view of the MIC threat. Therefore based on review of past models and extensive literature study of the subject, mapping and identification of influential parameters have been carried out. The parameters are sub-divided into one screening flowchart and detailed POF ranking tool, which facilitate RBI analysis in identifying risk. The main scope of the assessment was based on identification of what, when, where, and how to inspect, as well as what to report.

1.2 ‘Optimisation and Validation of Internal Corrosion Direct Assessment – Prediction vs Reality’, Lewis Barton, ROSEN Group (MACAW)

This presentation highlights the value of Internal Corrosion Direct Assessment in situations where in-line inspection is not possible. Using the defined NACE standard practice of corrosion risk assessment and flow modelling, the case study presents how accurate the prediction of corrosion hot spots and consequent inspection requirements can be. Most importantly, through expert analysis of the results it can limit excavation activities and provide cost-effective solutions to the client. Presented through a case study that demonstrates the accuracy of predicted corrosion rates vs. reality to within 1 % error, and use of available direct inspection results to fine-tune corrosion models to predict the condition of remaining sections of the pipeline.

4.1    ‘Designing Marine Reinforced Concrete Structures to Achieve Best Possible Up-throw of Current from Immersed Anodes to Bars above the Water Level’, John Baynham, BEASY

John presented results of a series of tests, performed using simulation, which investigated the amount of cathodic protection current delivered by anodes mounted in seawater to reinforcement bars positioned above sea-water level. He showed behavioural trends which are observed as total surface area of the bars is changed, and concluded that from a cathodic protection point of view the design of the reinforcement should minimise the surface area of the steel.

4.2   ‘Corrosion Failure Investigations and the Role of an Expert Witness’, Phil Munn, Midland Corrosion Services Ltd

Carrying out corrosion failure investigations requires a multi-disciplinary approach and a good knowledge of relevant standards, guidance documents and industry practice. Having an active quality management system in place greatly assists in controlling all aspects of the work, especially when carrying out several investigations simultaneously with more than one investigator. In our line of work, one should assume that all investigations could lead to potential litigation. When appointed as an expert in a legal case, it is imperative that one acts impartially and knows the limit of one's expertise. One's duty is to the court and not one's client. The stages in the legal process leading up to court proceedings and the trial were explained.