Compensated tension lift frames give offshore operators an independent means of supporting and heave-compensating the string during well intervention work from floating rigs. In May 2016, ICON Engineering completed the successful offshore trial rig-up of its then-latest Heave Compensated Tension Lift Frame (CTLF), installed on a semisubmersible drilling rig for a project offshore Western Australia.
What the compensated tension lift frame does
The CTLF is designed to be run in one of two roles: as the primary compensator for the operation, or as a back-up to the rig’s own drill string compensator, safeguarding against unintentional lock-up.
Run as the primary compensator, the frame supports the intervention string in tension and provides the heave compensation for the operation itself, while giving a safe work window for rigging up coiled tubing and wireline units.
That back-up role matters because of what happens when compensation fails. During locked-to-bottom operations, the string is fixed to the subsea well while the rig above continues to heave with the sea state. If the rig’s drill string compensator unintentionally locks up, vessel motion transfers directly into the string. An independent compensated tension lift frame in the load path provides a safeguard against exactly this scenario.
Designed for deepwater intervention operations
The design suits coiled tubing and wireline intervention operations where heave compensation is required — notably deepwater drilling and completions activities, which are carried out from floating rigs such as semisubmersibles and drillships where vessel heave is a constant factor in every operation over the well.
From trial rig-up to live operations
The trial rig-up was carried out offshore on a semisubmersible drilling rig. Trialling equipment of this kind under real offshore conditions — rather than only in the workshop — allows rig interfaces, handling and operating procedures to be verified before the unit is relied upon during live well operations.
Following the successful trial, the unit went into operation on a Western Australian project in 2016.
Part of ICON’s tension lift frame track record
The CTLF trial built on ICON’s established position in this equipment class. ICON has been supplying tension lift frames for subsea well completions and interventions from floating rigs since the late 1990s — both rigid frames, which hold the string in tension without compensation, and motion-compensated frames such as the CTLF — and in 2014 launched its Advanced Riser Tension Protector (ARTP) range of coiled tubing lift frames.
ICON continues to offer tension lift frames, heave compensation solutions and rental equipment for operators and drilling contractors, supported by riser analysis, rig interface engineering and offshore installation support.
