Ships & handling equipment for support of subsea work systems

The support of subsea work systems includes the launch and recovery of manned capsules, diving bells, submersibles, etc. Severe weather conditions - i.e., strong winds, rough seas, low temperatures - can easily make the launch and recovery operations hazardous. Ships and handling equipment must be designed and built to withstand the forces and loads of foul weather and to dampen the unpredictable and sometimes violent movements created by the sea. Despite the fact that significant progress has been made in the development of support ships and handling equipment, it still happens rather frequently that sophisticated and expensive subsea work systems are intermittently kept inactive because the weather is too rough, so called "weather standby". Sometimes an operation in progress must be aborted because of a sudden decline of the weather situation. Lockheed Petroleum Services Ltd. has developed a subsea oil and gas production system which uses a service capsule as an elevator between the support ship and the sea floor chamber. The company has studied, and is studying, several types of ships and handling equipment for launch and recovery of the service capsule and for support of the subsea operations. The eventual goal for the studies is to develop a support system that will meet the ever increasing demands of the oil industry with respect to weather independency and water depth. The paper describes, briefly, the service system that Lockheed is now operating in The Gulf of Mexico; the service system, which is now "on the drawing board", contemplated for North Sea operations; and a subsea support system using a submarine as support ship, which may become the next generation support system.