Development of Risk-Based Inspection Framework for Asset Integrity Management in Upstream Facilities, Uganda

Abstract

The development of upstream oil and gas production facilities in Uganda requires a robust asset integrity management approach capable of supporting safe, reliable, and cost-effective operation throughout the facility life cycle. As production facilities transition from construction and commissioning into operation, pressure-containing equipment such as process piping, flowlines, separators, pressure vessels, filters, heat exchangers, pig launchers, pig receivers, and storage tanks may be exposed to degradation mechanisms including CO2 corrosion, erosion-corrosion, microbiologically influenced corrosion, under-deposit corrosion, corrosion under insulation, and localized wall thinning. Failure of such equipment may result in hydrocarbon release, environmental contamination, production deferment, and major safety consequences. This paper presents a Risk-Based Inspection (RBI) framework for asset integrity management in upstream facilities under greenfield and pre-production conditions. The framework applies the principles of API RP 580 and API RP 581 while incorporating damage mechanism guidance from API RP 571, equipment inspection considerations from API 510, API 570, and API 653, inspection planning concepts from ASME PCC-3 and DNV-RP-G101, and criticality assessment principles consistent with NORSOK Z-008. The methodology integrates equipment inventory development, criticality assessment, damage mechanism identification, corrosion-rate screening, remaining-life estimation, Probability of Failure (PoF), Consequence of Failure (CoF), risk ranking, inspection planning, and corrosion monitoring feedback. A preliminary screening assessment was performed on 395 equipment records from CPF and wellpad systems. Static and pressure-containing equipment represented 177 items, equivalent to 44.8% of the equipment database. The assessment classified 21 items as Very High Risk, 14 as High Risk, 59 as Medium Risk, and 83 as Low Risk. Therefore, 35 items, representing 19.8% of the assessed static equipment population, were identified as the priority RBI population. The highest-risk equipment groups included pig launchers, pig receivers, high-pressure water injection interfaces, produced-water equipment, and selected hydrocarbon processing systems. Corrosion allowance screening showed that a 3 mm corrosion allowance corresponds to an allowable average corrosion rate of 0.12 mm/year over a 25-year design life, while a 1.5 mm corrosion allowance corresponds to 0.06 mm/year. Base-case corrosion allowance life ranged from 30 to 50 years for representative services; however, sensitivity analysis showed that an increase in corrosion rate to 0.15 mm/year reduces the life of a 3 mm allowance to 20 years, below the intended design life. The study demonstrates that RBI can be established before extensive operating history is available and can provide a proactive basis for inspection prioritization, corrosion management, risk reduction, and long-term facility reliability.