A mature offshore production pipeline system required a full pre inspection pigging and in-line inspection campaign to support ongoing integrity management. The system included a looped configuration flexible sections and known historic corrosion which increased the importance of inspection readiness and execution control. The scope evolved over time due to extended offshore activity and additional integrity requirements following inspection.
The key challenge was to ensure inspection readiness across a complex pipeline system while managing operational risk offshore. Multiple pig types were required to progressively clean prove and gauge the pipeline ahead of the inspection tool. Assurance was needed that each pig and tool was compatible with the pipeline bore and features. The offshore execution window was extended beyond the original plan requiring additional technical oversight and coordination. Following inspection, the operator also required a clear understanding of corrosion growth and remnant life to support future integrity decisions
Jee provided continuous pigging and inspection support from early desktop engineering through to offshore execution and post inspection assessment. Early activities included pipeline boremap generation, scope of requirements preparation and vendor selection. This was followed by areview of the pigging and pumping procedures and vendor documentation whilst the pig and ILI tool designs were subjected to technical assurance to ensure they met the project requirements. A structured pigging sequence was developed based on bore data debris expectations and inspection requirements.
Pre-mobilisation inspections were undertaken for the cleaning pigs and the inspection tool to confirm compliance with design providing confidence ahead of offshore mobilisation. During offshore execution Jee engineers acted as the technical focal point overseeing pre-ILI cleaning and gauging as well as inspection activities. This included coordination with offshore operations vendor personnel and platform management while whilst monitoring the pipeline cleaning and adjusting the pigging programme as required to optimise the cleaning and ensure a successful inspection.
Following completion of the inspection, Jee continued to support the project through close out engineering including a review of the inspection data, comparison with historic results and assessment of corrosion growth and remnant life including finite element analysis on the more onerous defects detected.
The campaign was delivered using a phased assurance model combining desktop engineering, pre-mobilisation inspection, offshore technical oversight and post inspection assessment. Each pig run was progressed against defined criteria to confirm cleanliness bore condition and tool performance before advancing to the next stage. Offshore decision making was supported by live technical review ensuring that changes in flow conditions operating pressures or procedures remained within assured limits. Following completion of the inspection Jee carried out corrosion growth assessment and fitness for service evaluation using inspection data and historical results to provide a clear integrity position.
Jee The pigging and inspection campaign was delivered with continuity of technical oversight from planning through execution and into post inspection integrity assessment. The structured approach allowed the operator to accommodate scope changes and extended offshore activity without compromising assurance or inspection quality. The inspection was completed successfully providing reliable data to support integrity decision making. The corrosion growth and remnant life assessment enabled informed planning of future inspection repair and operational strategies for the asset.
For more information on Jee’s pigging capability, visit www.jee.co.uk/pigging.
To contact Jee’s Head of Pigging, Sean Tucker, email sean.tucker@jee.co.uk, or call +44 (0)1732 371 371.