A quick and simple installation
The Horizontal Tie-In System was designed to enable a quick and simple installation process. The inboard hub along with guide post, which can be seen to the right of the picture, is installed subsea on the manifold and can be provided with a choice of long term or short term pressure caps. Our client opted for a short term pressure cap for their system and this can be seen in the middle, towards the bottom of the picture. This cap was designed so that it can be installed and removed subsea via ROV intervention. During installation of the outboard system a flexible is connected to the outboard hub and the outboard system is lowered in to place, aligning the guide funnel within the capture angle of the guide post. The outboard hub is designed to swivel on its axis. This allows the flexible to relieve any tension it may have as it is unwound from the spool on the installation vessel. As the outboard system is lowered down onto the guide post, any radial misalignment of the system is taken up by the guidance system which is design to centralise the outboard hub with the inboard system.
To provide a controlled final decent a control system has been implemented where, on the outboard system, an arm is extended prior to deployment. The outboard system initially contacts on this arm, which is then retracted via a 90° gearbox by the ROV. This system is designed so that it can also be used to split the outboard hub from the inboard to allow for seal replacement and seat cleaning activities.
Once the arm has been fully retracted the Optima connector can be closed and the system is ready to be used. A control panel on the inboard system can be included for which will enable subsea activities such as backseal testing to ensure a successful installation has been achieved, not shown in the picture.