Autonomous buoy for offshore well control and monitoring
Conventional subsea control systems require expensive electrohydraulic umbilicals that limit the maximum distance between platform and well. A proposed control-buoy concept is a hybrid well-control system with the reliability of conventional umbilical-based systems and the long-distance cost advantages of umbilical-free systems. Well 4-ALS-39 is a marginal gas well off-shore the state of Alagoas, northeast Brazil, in 25-m-deep water. Its production development became economically feasible with the use of an autonomous control buoy for well control and monitoring. A control and data-acquisition system installed on the buoy monitors wellhead pressure and temperature and controls the wet-Christmas-tree valves and production choke through a conventional electrohydraulic umbilical. A radio link between the buoy and shore ensures permanent supervision and interlock with the onshore pipeline valves and metering station. Because the onshore plant is normally unmanned, a dialed cellular-telephone line allows remote well monitoring and operation. The small buoy is completely autonomous in terms of energy. All energy required to power the system is generated locally by solar panels and a low-power, electrically driven hydraulic-power unit.
- OSTI ID:
- 634614
- Journal Information:
- JPT, Journal of Petroleum Technology, Vol. 50, Issue 8; Other Information: PBD: Aug 1998
- Country of Publication:
- United States
- Language:
- English
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