Mechanical Umbilical-Less Installation of Tubing Hangers

Abstract

Operators with subsea developments on the Norwegian Continental Shelf have the last 20 years aimed for better efficiency and reduce equipment and personnel needed on the rigs in relations with subsea completions. Drivers have been reducing HSE risk, reduce need for modifications on the rigs to accommodate for subsea related equipment such as reels and workover control systems, and reduce cost, rig time and emissions. Many measures have been implemented such as removing need for landing string and wireline operations with deep-set pump-open or disappearing barrier plugs, installing Intervention and Workover Control system (IWOCS) to operate all systems suppliers’ tools from same unit, use of ROV Workover Control System (RWOCS) subsea HPUs to control the Xmas Tree (XT) to remove the tree running tool (TRT) umbilical, developing a hydraulic-electric remote operated control system communicating on wired drill pipe to the tubing hanger running tool (THRT) to remove the need for THRT umbilical and IWOCS, to mention some. This paper describes one of the last inventions; a mechanical tool for installation of tubing hangers (TH) that also removes the need for remote communication and hence dramatically reduces complexity and potential for faults. The mechanical tubing hanger running tool is called THRUT and has been developed by CCB Subsea in cooperation with Equinor. First umbilical-less subsea completion ever run with a THRUT was successfully conducted on the Equinor's Heidrun field on well E-2 from the Transocean Encourage drilling rig in March 2022. Following the first well, the THRUT has been run on 8 more wells for Equinor and 3 wells for Norske Shell. The tool concept is accommodated to interface to any kind of subsea horizontal XT (HXT) systems delivered by either Aker Solutions, TechnipFMC, OneSubsea, BakerHughes, or other system suppliers. And also, the tool is operated offshore by the subsea system supplier in charge of the subsea completion, no extra personnel from CCB Subsea is required offshore. Result is an efficient and robust tool with profile of low risk, low cost and less personnel needed. The paper describes the philosophy and requirements for the system design, the device functioning, and method for mechanical umbilical-less installation of TH in subsea HXTs, and also summarizes the most important results and operational experiences with regards to the advantages related to HSE, time, cost, personnel need, logistics and rig interface.