Background

An Operator client had the requirement to carry out a pipeline cleaning and inspection campaign on two pipelines on their West African assets as part of a routine maintenance regime.  Due to lack of expertise in country, Prism were requested to supply representatives to oversee the execution.

Prism personnel were to ensure the right equipment was being used, procedures were being followed and to provide guidance on the next steps following a progressive cleaning campaign prior to launching the inspection tooling.

Coordinating logistics during the scope was challenging as one of the launch assets was normally unmanned, requiring personnel to travel by boat each day, limiting the hours available for working. The same was also found of the onshore receiving site, which was in a remote location with restrictions on personnel movements during the hours of darkness.

Project Description

Prism Energy’s role was to oversee pigging operations on two separate pipelines.

  1. Wellhead production tower -> FPSO.
  2. FPSO -> Onshore terminal.

 

  • The Wellhead tower to FPSO line is a 6km line for multiphase fluid which is to be processed on the FPSO. This scope was the second phase in a three-phase programme which will culminate with the launch of an Inline Inspection tool (ILI). In phase one, a hard bodied pig was run with a gauge plate which was recovered with a deflection noted on the gauge plate. Following the launch of several cleaning pigs as part of a progressive campaign, a smart gauge pig was then run to ascertain the cause of the deflection. Following the gauge pig, a pathfinder pig was run to measure debris within the pipeline.

 

  • The FPSO to onshore gas export line carries dry gas onshore over a distance of just under 20km. Export gas from the FPSO was used as a motive for the pigs to reach shore. This was a repeat of a campaign completed in 2021 where the client was gathering data on a known defect in the line and detected deflection of the line and damage likely caused by anchor dragging. The client wanted to re-run the ILI to confirm no further degradation to the line conditions.

Project Outcomes

With the completion of the scope the following was achieved –

  • Successful deployment of cleaning pigs in both lines assuring line cleanliness.
  • Successful data gathering performed by the intelligent tooling and Inline Inspection tools (ILI).

Prism Energy’s Involvement

Prism Energy’s consultants reviewed the pigging programme, equipment and procedures prior to mobilisation. Upon arrival on the Ivory Coast, they completed equipment checks prior to commencing operations. Additionally, Prism Energy personnel were onsite to oversee the loading, launching and receipt operations, before feeding back run and pig conditions post run, offering advice on progression of the campaign.