The research & development unit of oil major Total has joined with Plexus to develop a new and safer subsea wellhead, using Plexus’ patented POS-GRIP technology.
Maersk Oil, Shell, Wintershall, Tullow Oil, Eni and Oil States Industries and the UK division of a leading drilling contractor and oil and gas technology solution consultancy SafeKick are existing partners in the joint industry project.
According to Plexus, the POS-GRIP HGSS subsea wellhead will be safer and have fewer parts in the wellbore, while also sealing and locking down hangers as soon as cementing of the well is complete.
It is being designed to address technical issues and requirements brought up by regulators following the Macondo incident in April 2010. Indeed the JIP was forged that year.
To date, the technical specification of the “base product” has been finalised with detailed engineering design now under way. The conceptual detail of the subsea hydraulics and interface with control systems is also complete, and design of qualification test fixtures has started.
Physical testing of various elements of the system should begin early next year.
The next stage will be to complete formal performance verification testing, and then to find an application for a field test.
Key features that Plexus is looking to incorporate into its new POS-GRIP HGSS Subsea Wellhead design include:
o 18-3/4 full bore system, rated to 15,000 psi 350deg F
o Upgradeable to 20,000 psi, 450deg F
o 4,000,000 lbs “instant” casing hanger lockdown capacity
o Avoidance of problems associated with use of lock down rings
o Annulus monitoring and bleed-off capability to address sustained casing pressure (“SCP”) situations, with diagnostic and remedial capability
o Ability to open and reseal the casing annulus to enable remedial cement job procedures
o Rigid metal annular seal technology qualified to match the standards for premium casing couplings
o Meeting the requirements of API 17D/ISO 13628-4