Aberdeen-based Helix Well Ops (U.K.) Limited, a U.K. subsidiary of international offshore energy service company Helix Energy Solutions Group, has completed the industry’s first riser-based coiled tubing intervention project from a mobile offshore drilling unit (MODU) class light well intervention vessel (LWIV).

The project was conducted from the company’s MODU class mono-hull vessel Well Enhancer, which was designed to perform operations such as wireline and coiled tubing interventions, the company said in a news release.

“Delivering coiled tubing well intervention from this type of vessel has been anticipated by the oil and gas industry for some time,” Helix said. “In the quest to enhance oil recovery and reduce the costs associated with subsea well abandonment, it may be seen as a potential industry game changer due to its cost effectiveness over traditional rig-based methods.”

Helix carried out the first live riser-based coiled tubing intervention project from a LWIV in the North Sea earlier this summer. The work was done in water depths of 83 m (275 ft). The project involved drifting and milling to 4,400m (14,500 ft) and performing a reservoir saturation tool log before perforating 267 m (877 ft) of reservoir section in four runs, followed by a venturi clean-up, the release said.

When combined and interfaced with Well Ops’ patented technology and equipment, the coiled tubing unit virtually eliminates the effect of vessel motion, the company said. It also reduces the coil fatigue toward that of a fixed installation or platform. Altus Intervention provided the coiled tubing unit.

“Initial results of the intervention indicate an increase in daily oil output of over 1,500 barrels of oil equivalent per day,” the company said. “Helix Well Ops’ coiled tubing intervention system is designed to operate in water depths of between 80 m and 200 m and can deploy a variety of coil sizes up to 2⅜ in and 20,000 ft in length.”