Unity, Europe’s largest provider of well integrity solutions, is developing a new additive manufactured lightweight gate which can be retrofitted to Xmas Tree gate valves to remediate seal integrity issues in low-pressure wells. The new technology is a result of a collaborative research and development project with Net Zero Technology Centre and Spirit Energy.
The gate has been designed as a solution for late life, depleted and shut-in offshore wells, where the tubing head pressure is too low to effectively seat the gate and seal the well. Unity’s patented design reduces the weight of the gate by around 60%, while retaining its intrinsic strength and would save operators in the region of £250,000 per well by replacing a single surface component rather than the complete well control package.
A full replacement of bespoke, low-pressure wellhead equipment would also require significant downtime, so this new solution offers the opportunity to rapidly remediate the issue and minimise associated production loss.
The UKCS and other regions have many low-pressure brownfield wells, with increasing numbers continuing to enter this phase. The most recent ‘Wells Insight Report’ from the UK’s North Sea Transition Authority, published in October 2022, states that the current active UKCS well stock comprises 2,629 wellbores, of which 1,661 are producing, while the number of shut-in wells rose by 65 to 781 in 2021.
Shut in well stock is now at a historical high with 30% of all wells being shut in, with significant intervention on infrastructure cited as one of the top three limiting factors. This is well above the KPI of 10% set by the Wells Task Force and many of these wells might still be valuable if production was restored.
Stuart Slater, Technical Sales Director at Unity explained: “The use of metal additive manufacturing means that we can offer attractive cost-savings and efficiencies to the industry, reducing raw materials, waste and operator investment in stock holding. The delivery of single items is fast and more energy efficient than traditional forgings, with an impressive 90% average reduction in lead times. But the real saving in this case is achieved by approaching the problem from a different angle, so rather than replacing the whole surface well control package we can quickly replace just a single small component, which offers huge cost and efficiency benefits.”
With a patented design, engineered by the team at Unity, the new technology is entering the latter stages of development. Prototype testing has already been completed on a 2-1/16” gate and a 5-1/8” gate is now in manufacture to further prove the concept and qualify the product for commercialisation.