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Well Enhancer Completes First Well Intervention Job in the North Sea for Nexen Petroleum UK

18 December 2009

The newest addition to the Helix Energy Solutions Group global well intervention fleet, Well Enhancer, successfully completed her inaugural well intervention project on Nexen Petroleum UK,'s Buzzard S2 well in the North Sea in October 2009.

The well intervention was carried out following comprehensive system trials, including personnel familiarization and training on a test well provided by Nexen.

The Subsea Intervention Lubricator, (SIL), a 7-3/8” bore single-trip system designed and built in house by Helix Well Ops, was successfully deployed via the vessel's integrated skidding and handling system in adverse weather conditions. The vessel's performance exceeded expectations; with a significant wave height of 5 meters and winds of 45 knots, heave at the moonpool rarely exceeded 2 meters.

“The Well Enhancer's moonpool design and skidding system, coupled with our ability to disconnect and reconnect the control umbilicals subsea, enabled us to work safely in weather conditions that would have sidelined other intervention vessels,” said Steve Nairn, Vice President of Helix Well Ops UK. “Thanks to these features unique to Well Enhancer, the operation was completed on schedule in spite of difficult weather.”

Over the course of the ten day operation, Well Enhancer performed production logging, fluid sampling and wireline services including sand detection and flow profiling on the well. The S2 water injection well was entered with a combined log / fluid sampling service, with additional sand detection and flow profiling equipment onboard. All onboard systems were utilized successfully.

Construction on the vessel began at the IHC Krimpen shipyard in July 2007, with the christening ceremony taking place in May 2008. The Well Enhancer then underwent fitting of its multipurpose tower and specialized well intervention equipment prior to sea trials.

“You might say that the Well Enhancer is the only brand new intervention vessel with a 15-year track record,” Nairn said. “When first began the design process, we took advantage of the lessons learned from operating our other North Sea intervention vessel, Seawell. That experience led us to include the SIL and skidding system in the new vessel's design, and include provisions for a coiled tubing intervention system as well.”

Well Enhancer features a Huisman Itrec multipurpose tower for deployment of its subsea intervention tools and equipment. The system operates in water depths to 1,000 meters while handling 150 metric tons, and features both active and passive heave compensation. Additionally, the vessel includes an 18-man saturation diving system rated to 300 meters, with four decompression chambers and two dedicated diving moonpools.

Well Enhancer is specifically engineered for cost-effective well support, intervention and construction operations in the North Sea. The vessel was built in accordance with Det Norske Veritas rules for ships, UK Maritime and Coastguard Agency Regulations and also meets UK Health and Safety Executive requirements. Due to its rigorous engineering, Well Enhancer qualifies as a full DP3 vessel and can engage in well support, intervention and construction operations around the world.

Helix Well Ops is a Helix Energy Solutions Group company engaged in rig alternative subsea well intervention and drilling. As such, it engineers, manages and conducts well construction, intervention and decommissioning operations in offshore waters from 200 to 10,000 feet.