Flow modelling and corrosion risk assessment are used to study a challenging multiphase pipeline, where the main focus is the identification and prioritization of critical locations for direct inspection (DA). Through the internal corrosion direct assessment (ICDA), flow modelling sensitivity studies is carried out to identify critical locations with risks of high shear stresses and water holdup. Through corrosion risk assessment (CRA), the critical locations were narrowed down to four primary locations, which through direct inspection could provide the information necessary to estimate the overall pipeline condition. It is highlighted that without the In-line inspection (ILI) data, selection of inspection locations becomes problematic. However, carrying out a CRA in combination with dynamic flow modelling can build a more representative analysis and assist with effective engineering decision making.
One of the available industry standard tools that can assist with demonstration of pipelines’ integrity requirement is an approach that integrates flow assurance with corrosion modelling known as Internal Corrosion Direct Assessment (ICDA). More specifically, an industry standard multiphase dynamic flow model (OLGA) with well-established corrosion models, CRA and engineering judgement have been employed to identify and prioritize inspection locations.
A benefit of this work is the validation of predictions by both OLGA and the corrosion engineer in close adoption to the procedures of the NACE ICDA standard practice. Considerations from corrosion engineering aspect on modelling requirements and corrosion diagnosis will be presented, where the primary focus is on identification of hot spots and consequent inspection requirements in order to limit excavation activities and provide cost-effective solutions to the client.