Aquaterra Energy and Plexus Holdings have developed a light weight, dual barrier high-pressure high-temperature (HPHT) riser system which can be deployed by a jackup as an alternative to semisubmersible installation for HPHT well operations.
The technology is suitable for shallow water depths up to 150m and harnesses the combined capabilities of the companys’ respective subsea technologies. By uniting Aquaterra Energy’s HPHT riser system and Plexus’ POS-GRIP wellhead engineering technology, an inner riser string is installed inside a conventional high pressure riser (HPR) to span the gap between a dry surface blowout peventer (BOP) and a wet subsea tree. It provides full 20,000 psi capability and utilizes all metal-to-metal gas tight seals on both the external and internal riser string. The system also aims to eliminate the issues associated with surface wellhead developments that contain elastomeric seals, particularly those located between the mudline and surface.
In comparison to semi-submersible mobile units, new generation, heavy duty jackup drilling units can now undertake drilling, completion, intervention and abandonment activities at lower day rates. Moreover, they can potentially mitigate the heavy loading implications and weather constraints often associated with semi-submersibles and extend the operating envelope.
The joint solution represents an incremental step forward in subsea capabilities, said Ben Cannell, product line manager: riser and conductor solutions, Aquaterra Energy.
“The dual barrier HPHT riser system facilitates safe and effective drilling operations in HPHT conditions and provides a structurally sound, pressure retaining conduit between the subsea wellhead/tree and the rig’s surface BOP,” said Cannell.
“Handling HPHT operations safely, economically, and with environmental sensitivity, calls for highly specialized equipment and technology to exploit future reserves,” said Craig Hendrie, technical director, Plexus Holdings. “This is a new, technology-led drilling proposition to the international market and is one that directly addresses the industry’s cost-reduction agenda. Amid the ever-increasing industry focus on HPHT operations, this methodology represents an innovative and cost-effective alternative while maintaining safety, integrity and operational performance.”
Image: Dual barrier HPHT riser system/Aquaterra Energy
Subscribe
