Rotech Subsea Completes North Sea Decommissioning Scope

Subsea excavation pioneer, Rotech Subsea, has successfully completed a North Sea rock placement removal scope for a major oil and gas offshore contractor.

Rotech Subsea’s state-of-the-art TRS2 Controlled Flow Excavation (CFE) and Suspended Jet Trenching tool was mobilized from Aberdeen for the North Sea for the decommissioning scope at just four day’s notice in early September.

The decommissioning scope, in offshore Netherlands, saw the company carry out 50m of rock dispersal work at around 43m water depth around flanges to expose spool pieces at the oil and gas asset. Rock had to be removed for access prior to the de-commissioning process commencing.

The rock around the asset was found to be consolidated (cemented) and 2” to 12” in size. Due to this scope being beyond the capabilities of a standard ROV type dredger, the client selected Rotech Subsea’s state-of-the-art, next generation controlled flow trenching and excavation TRS2 tool. The tool removed the 1.5m depth of rock quickly and effectively allowing access to continue the decommissioning operations.

Speaking about the short notice project for a major offshore contractor, Rotech Subsea Director of Subsea, Stephen Cochrane, said:

“We were delighted to be able to assist the client who commissioned us on this extremely short notice scope. It was an incredibly tight turnaround to have kit on the quayside in Aberdeen within four days of the initial call. It’s a real testament to our team that we were able to mobilize our TRS2 CFE jetting system within the timeframe.

“Despite currently being operational at a number of international sites working on cable trenching and sandwave campaigns, we won, mobilized and are now managing and executing the North Sea job whilst also servicing numerous other renewables and oil and gas projects in UK, European and Asian waters.”

Rotech Subsea’s patented RS technology provides capabilities not available through traditional mass flow excavation. They offer solutions in controlled flow trenching, excavation, burial / backfill, deburial and seabed debris clearance for: Cable array and export, trenching / deburial; Cable joint burial / IRM; Pipeline trenching / deburial; Backfilling for cable / pipeline protection; Jack-up leg / spud can clearance; UXO deburial / access; Freespan correction / seabed rectification; Harbor / pontoon seabed clearance; Sand wave clearance / cable and pipeline route clearance; Umbilical and flowline trenching / deburial; Salvage reburial / access; Access to subsea structures / IRM / decommissioning; Drill cuttings removal; Cable / pipeline umbilical recovery; Rock removal / relocation; and Rock dump dispersal.