West Africa Pipeline Walking Mitigation with Pipe Clamping Mattress



  • Year
  • Location
    West Africa

Project Overview

The Operator was experiencing high-temperature, high-pressure flowline walking in deep water away from an FPSO. The walking was significant enough to cause a failure at the riser base which required the flowline to be shut down. Urgent walking mitigation was required before start-up and production could recommence. We initiated a full-scale onshore FAT with the Operator’s installation contractor to streamline the installation process and ensure logistic efficiency. We were able to fast track the project from detailed design to tank testing, FAT, fabrication and delivery within three months. We also custom-designed a handling frame to reduce hook run time during installation.

MMA Solution

MMA was contracted to complete the detailed design and supply of Pipe Clamping Mattresses to arrest the walking of the pipeline prior to start-up. The scope consisted of:

  • Complete detailed design
  • Centrifuge tank testing
  • 18 x PCMs
  • 18 x Log Mats
  • 2 x Bespoke lift frames
  • Full-scale onshore FAT


We carried out scale model centrifuge tank testing to refine the quantity of PCMs required plus customised the interface design with the pipeline to further increase restraint loads.

Technical Details

Description Dimensions (m) Min. Weight in air (Te) Min.
Submerged Weight (Te)
PCM L 3.5 x W 4.4 x H 0.56 15.0 8.7
Log Mattress L 3.2 x W 5.2 x H 0.6 16.8 9.6

MMA Innovation / Value Added

The Operator was pleased with the solution, saying: “MMA delivered an excellent product for us on an accelerated schedule. The fabrication and installation went very smoothly and is a credit to the MMA team and their elegant design of the PCM.” – Operator Subsea Project Engineer

For more information on our solutions, please contact our team at:

Blue Solutions
+61 8 9431 7431

Category: Africa