Case Study

Engineering & Fabrication

Ultra-Deep-Water Drilling Project: X-Tree Sea-fastenings & Deployment

TEXO Engineering & Fabrication was awarded the project to deploy four Baker Hughes X-trees to a 2700m ultra-deep water drilling project off the coast of Mauritania & Senegal, in collaboration with Valaris and BP.

The project included:

  • Tree lifting and handling feasibility study, including on-board clash detection
  • XT subsea installation and vessel motion analysis
  • Design, engineering, fabrication and installation of:
    • 3 specialist rigging arrangements
    • Purpose-built spreader beams
    • Multiple landing grillages and interface solutions
    • Sea fastening and securing

The client chose to work with Texo Engineering & Fabrication because we have developed an excellent working relationship based on multiple successful project executions. Our integrated approach has repeatedly demonstrated benefits in reducing bottlenecks and associated schedule delays, minimising risks and facilitating tighter available budget and project cost control.

The solution

An X-tree is a multi-valved structure consisting of valves, spools, and fittings used to control the flow of oil from the well. Also know as a Christmas tree, it regulates pressure and controls flow during drilling. The outlet valve can be connected to an onward distribution network.

For this project, we needed to fabricate heavy steelwork grillages, which were built at our dedicated fabrication facility in Dundee. The project also required specialist rigging components for ship-to-ship handling as well as subsea deployment and installation at a depth of 2700 metres.

One of our main challenges were to ensure that when the X-trees were lifted from the supply vessel, there was a clear path along the drill ship to the storage destination on the main vessel, this was part of our analysis and feasibility study work.

Ultra-Deep-Water Drilling Project: X-Tree Sea-fastenings & Deployment

The results

Our clients were delighted with the part our teams played in this complex project, TEXO’s involvement summarised below from client rep:

“The loading of the trees, storage, deployment and installations were modelled and studied step by step. a tree storage and deployment strategy on board the DS-12 saved the project a minimum of £4.3m in addition to de-risking schedule uncertainty.”

And as direct client feedback TEXO received the below email of gratitude:

“Thank you and I do appreciate your and your team’s support throughout the planning and final execution stage. You have done a really good job and will be looking forward to having more work with you in future.”

Ultra-Deep-Water Drilling Project: X-Tree Sea-fastenings & Deployment