How SSCS enables smooth drilling operations on the seabed

When Seabed Scour Control Systems (SSCS) was approached for a solution to prevent drill cuttings from the thick clay layer on the seabed invading the foundations of a new fixed drilling platform in Canada, Ed Cole knew he would be up against stiff competition.

“It was a huge job that needed to be turned around quickly, but I was confident that we could provide an innovative solution to solve the issue within the time constraints. We are only a small-medium-size company in Great Yarmouth and were up against some very large companies bidding their solutions.”

Ed “thought creatively”, came up with the concept of a bespoke impermeable membrane comprising 24 individual sheets to span across rock mounds around 100m under the Atlantic, where the foundations of a 210,000-tonne concrete drilling structure base would be installed.

“We were approached because they had seen our frond mat seabed scour solution that replicates seagrass on the seabed. We have been making frond mats for 40 years – this was a totally different challenge, though.”

The 145m high concrete gravity structure (CGS) and topside module drilling, with foundations measuring 122m – larger than a football pitch – was designed to be lowered onto mounds of large rocks that act like mattress springs to cushion the CGS landing.

Drilling takes place through the centre of the CGS into a thick clay layer. Engineers needed a solution to prevent clay particles churned by the drilling from invading the foundations of the fixed drilling rig, which will be tied back to a Floating Production Storage and Offloading system (FPSO).

Ed, SSCS subsea division manager, came up with a concept and asked his sister, Charlotte Cole, an architect, to create a 3D model of the solution.

“I proposed making a membrane sheet that was positioned around the inner ring, so the structure was located on the sheet. The sheet will block the flow and stop clay particles from getting into the foundations.”

Ed pitched the solution of a series of super strength large mats that created the giant membrane to the client and the contract was awarded in August, with installation scheduled for autumn 2024.

“This is an extraordinary, specialised project for us; however, it is more in line with what I am trying to develop in SSCS, coming up with innovative solutions for projects.”

Ed Cole with some of the webbing to create the impermeable membrane to sit deep in the Atlantic Ocean (Image: TMS Media) The project – worth approximately £1 million to the company – had a tight turnaround time and Ed needed additional specialisms, so he turned to two other Norfolk companies, Wroxham-based Jeckells the Sailmakers and Fakenham-based waterproof lift bag manufacturer JW Automarine (JWA), to bring his design to reality.

Using thick PVC, JWA created a robust membrane with a polyester weave/mesh sandwiched between the PVC layers to guard against any potential puncturing throughout the product’s 25-year life span.

Steve Bell, JWA design engineer, said the team radio frequency welded together PVC panels, and as the sheets got larger, they were tricky to handle.

“We had six people on the shop floor doing over time ‘growing’ the mat by welding pieces together to make separate membranes,” said Steve.

To provide further puncture resistance mitigation, Ed suggested that an additional large wear patch could be made and joined to the JWA membrane to eliminate all risk of puncture from the rock mounds.

The wear patch strips were taken to Jeckells the Sailmakers, which, after two centuries making products to go above the water, carried out its first commission designed to be used under water.

Sewing machines that usually make sails for super yachts were used to stitch strips of webbing together to form the large wear patches.

James Mortimer, production manager at Jeckells the Sailmakers, said there were nearly 1,000 sections of webbing to complete the panels.

“We had everyone in the company working on the project to meet the tight delivery schedule,” said James. “There have been 10 people on the job with a team of SSCS employees engaged in the manufacture.

“We worked at the weekends to deliver a three-week project within one and a half weeks.”

After the membranes and webbing were stitched together, they were taken back to SSCS’ base on the Harfrey’s Industrial Estate, Great Yarmouth for inspection and sign-off by a third-party quality assurance engineer.

“It was a totally different challenge for us, but we rose to the occasion, collaborated with two other Norfolk businesses that had niche skill sets in different sectors, and created a solution as a team,” said Ed.

“We are all extremely proud to have successfully delivered this innovative solution, which will support the completion of a major drilling project.”