VESSEL REVIEW | Offshore Oil 696 – China's first offshore well stimulation vessel commences operations
China National Offshore Oil Corporation (CNOOC) has expanded its fleet with the recent acquisition of a new well stimulation vessel (WSV) built by Wuhu Shipyard.
Offshore Oil 696 (海洋石油696; Haiyang Shiyou 696) was built to a design by China State Shipbuilding Corporation subsidiary Shanghai Merchant Ship Design and Research Institute (SDARI).
The vessel will be operated by CNOOC on well stimulation activities to help enhance production at oil and gas fields in China’s offshore waters.
Largest vessel of her type
The newbuild has an LOA of 99.8 metres (327 feet), a beam of 22 metres (72 feet), a depth of 9.9 metres (32 feet), and a diesel-electric propulsion system.
SDARI said she is China’s first offshore oilfield WSV (whereas majority of WSVs currently in operation are in the United States and Europe) while her dimensions make her the largest vessel of her type in the world.
The vessel was designed to be capable of injecting high-pressure acid or a sand-and-fluid mixture into wellbores upon the completion of drilling activities.
Full range of well stimulation equipment
When the bottom pressure of the wellbore has exceeded the formation rupture pressure, a series of gaps are artificially created within a certain range along the wellbore. This then allows the oil and gas in the well to flow into the wellbore through these gaps and be extracted from the surface.
The vessel’s fracturing equipment includes liquid and stand storage tanks and mixing facilities. The mixing and fracturing processes are fully automated, and the crew can monitor the progress with the aid of digital displays.
Intelligent systems and diesel-electric propulsion
Intelligent systems provide early warning of possible equipment issues in addition to supporting remote operation and decision making with regard to maintenance. To ensure direct supervision of activities on the aft deck, the wheelhouse also boasts rear-facing windows providing the bridge crew with unobstructed visibility.
The diesel-electric propulsion setup consists of five generators, two azimuthing thrusters, one retractable manoeuvring thruster, and two bow thrusters.
Offshore Oil 696 was built in compliance with China Classification Society requirements.
