Maersk Oil North Sea UK has granted Plexus Holdings $400,000 in funding for development of a 20,000-psi (1,379-bar) high-pressure/high-temperature mudline tieback wellhead system.
Testing and manufacturing of the prototype is under way under a joint industry project, with final deployment and commercialization targeted for mid-2012.
The tieback system design, which will feature Plexus’ metal-to-metal “HG” seals, should allow HP/HT exploration wells and pre-drilled production wells to be converted into either subsea or platform producing wells.
These wells, which can cost between £50 million ($76.5 million) and £300 million ($459 million), currently are abandoned after drilling.
According to Plexus no other technology is available to “save” or “convert” such wells. This is partly due to the fact that existing standard mudline suspension technology employs threaded connections which Plexus claims cannot be reliably reconnected or tested with the corrosion-resistant materials required for HP/HT production
The company says its patented POS-GRIP wellhead technology, which uses a friction grip technique rather than threaded connections, can facilitate an HP/HT mudline tieback of up to 20,000 psi without requiring any rotation.
In addition, the company claims the HP/HT mudline tieback system could shorten the development cycle of an oil and gas field by several years, allowing pre-drilling of production wells to start before a production platform is put in place.