Operations
Tension Control
Hold steady tension on the riser through vessel heave — to protect the string and keep working as the sea state builds.
In drilling and workover, the riser has to stay in positive tension while the vessel heaves. Lose it and the string risks buckling; let tension spike and connectors and the wellhead take the load. Norwegian Dynamics supplies tensioning equipment that absorbs heave and holds tension within a controlled band: the SIRIUS tensioner for backup and workover compensation duty to DNV OS-E101, and VEGA active heave compensation where closed-loop feedback is needed to track a tension setpoint. Steadier tension means a wider operating window and a de-risked path through marginal weather.
What we control
Backup riser tensioning
SIRIUS provides emergency and backup riser tensioning when the primary system is offline or under maintenance, holding the riser in positive tension with DNV OS-E101 as the design basis, supporting continued operation where the backup case is approved.
Workover compensation
For workover and intervention, SIRIUS delivers controlled compensation across the running stroke, keeping tension steady as the vessel moves so loads on the string and wellhead stay within their envelope.
Hydro-pneumatic tension band
SIRIUS uses hydraulic cylinders working against nitrogen accumulators to absorb heave passively and keep tension inside a defined band, without external power for the core compensation function.
Active setpoint tracking
Where passive compensation is not enough, VEGA adds active stroke control with an HPU and battery backup to track a tension setpoint under feedback, for cases that demand tighter control than a passive band.
Choose the right compensator
The engineering behind it
For the full method and worked examples, see the engineering guide — forces are sized to DNV-RP-N103 and checked against the crane’s derated capacity.
Send your riser configuration and tension capacity — we will return a tensioning recommendation.
Send SWL, stroke, sea state, payload and operation sequence. We’ll come back with a recommended compensator, an operating-window view and the next engineering step.