Abstract: A riser recoil control system (10) adjusts tension forces (F1, F2) applied to a marine riser (60), which is attached to an anchored, floating vessel (30) and a wellhead (80). The riser (60) is attached to the vessel (30) using tension forces (F1, F2) asserted by riser tensioners (20). Each tensioner (20) has an air shutoff valve (110), and an orifice-controlled fluid valve (120). A disconnection sensing means (200) provides a disconnect signal when the riser (60) is disconnected from the wellhead (80), which closes the valves (110, 120) and adjusts the tension forces (F1, F2) applied by the tensioners (20). The invention includes a method for adjusting the tension forces (F1, F2) applied to the riser (60), including sensing the disconnect signal and adjusting the tension forces (F1, F2) supplied to the riser (60) by closing the air shutoff valves (110) and partially closing the orifice-controlled fluid valves (120).

Abstract: An automated riser recoil control system (10) including a plurality of riser tensioners (20), a vessel heave measurement system (210) and a control processor (70) with each tensioner (20) having a piston travel indicator (27) which signals the processor (70) and a method of operation is disclosed.

Abstract: In one embodiment, the automated riser recoil control system (10) includes a plurality of riser tensioners (20), a vessel heave measurement system (210), and a control processor (70) in electrical communication with the heave measurement system (210) and riser tensioners (20). Each tensioner (20) includes a piston travel indicator (27) which signals the processor (70). In another embodiment, a method for adjusting at least one of the tension forces (F1, F2) applied by the tensioners (20) to the riser (60) includes determining piston travel velocity for each riser tensioner (20), measuring vessel heave velocity, calculating the differences between each of the piston travel velocities and the heave velocity, and adjusting the tension force when some preselected number of the velocity differences exceeds a preselected critical velocity difference. Tension force control is typically effected by throttling at least one fluid flow rate within one or more riser tensioner (20).

Abstract: The active deployment system (10, 10′) comprises a passive cylinder system (410) coupled with an active cylinder system (400). The passive cylinder system (410) including a pre-charged accumulator (440), provides load balance for the equipment or other mass/load being deployed. Pressure provided to the blind end of the passive cylinder supports the load (60), such that the passive cylinder is balanced mid-stroke with the load hanging from a cable (30). A sheave arrangement (120, 130), placed at opposite ends of the passive cylinder-active cylinder combination, is used to introduce a line travel multiplier for cylinder displacement. The active cylinder is controlled hydraulically to add or remove load to/from the passive cylinder system in order to provide a compensating balance. The method comprises the steps of measuring a heave movement (velocity and direction), and adjusting the tension force applied to the cable (30) upon determining that the heave velocity exceeds a pre-selected critical velocity.