Deepwater maintenance and de-sanding pigging
We were asked to define a region-wide maintenance pigging strategy for a major operator. The scope involved ensuring the capability to carry out this strategy was in place for the pigging of five ultra-deepwater production lines at two FPSOs in West Africa, including multi-diameter flowlines, flexible pipe sections and passage of wyes.
We reviewed the process data and principal threats associated with each line (wax, sand, asphaltenes etc.) and produced a region-wide cleaning strategy detailing the types of pigs that would be required to remove the potential debris types from each line, as well as the recommended maintenance pigging frequency. We subsequently generated an SoR for each FPSO, detailing the requirements for the cleaning and de-sanding pigs required at each facility.
We managed a competitive tendering process for the provision of the pigs and tracking equipment, providing comments on and subsequently approving the proposed detailed pig designs. We also tracked the manufacture of the pigs, and visited the vendor premises to review the as-built tools and approve them for shipment.
In addition, we provided a document pack of risk assessments and operational and assurance documentation to ensure each campaign was carried out successfully. For each FPSO this included:
- Detailed risk register and sign-off of residual risks
- Pig design check sheets for all pigs
- Vendor documents for pig handling, operation and storage
- A stuck pig guidance document
- A compliance review with the operator’s pigging engineering practices, including sign-off of any required deviations by the appropriate technical authorities
- Review of the operational pigging procedures including input into revision of procedures (including arrangement and management of HAZOP)
- Bridging document for maintenance pigging activities
Our experience of complex pigging requirements helped us to identify the best tool and vendor for the project, minimising risk and maximising the probability of a successful pigging campaign.
Our independence of the principal pig vendors makes us perfectly placed to manage a pigging tender process and recommend the best technical and commercial solution to the specific needs of a project.