The first use of the Agip SAP System (Sistema Alti Fondali), an installation and maintenance system for subsea production systems up to 1.000 m water depth, was successfully performed on the Luna 40 well in 180 m w.d..
The system successfully installed the christmas tree, flowline jumpers, control system audhigh pressure cap as well as deploying the LMRP to allow the commissioning of the well. The SAP system performed all the planned tasks during the installation of the Luna 40 subsea tree and now has to be considered an operational success. The system is based around a Master Vehicle that provides hydraulic power to, and controls a set of dedicated work modules. During the 2 test and 5 working dives, the Master Vehicle and the modules were subs for a considerable period of time, up to 75 hours continuously, without any operational failures. This installation uncovered some system deficiencies that will have to be studied to improve the reliability and operability of the system.
From the experience gained during this operation it has been shown that the system o f a Master Vehicle providing locally generated hydraulic power is a feasible approach to many subs installation problems. This system should therefore not be considered just a tool for the installation of christmas trees, but should be considered for other subsea tasks, for example existing equipment workovers, flowline pull-in system, pipeline repair system, etc..
This paper describes the SAP system including improvements to be performed before being used operationally in up to 1.000 m of water and over. It also cover the necessary modifications required to allow the system to be deployed from a wide range of installation vessel.
DYNAMICS OF A NOVEL HEAVE-COMPENSATED DEEPWATER INTERVENTION SYSTEM
Denby G. Morrison and Richard C. Swanson, Shell E&P Technology Company, USA
John J. Pritchard, Shell Offshore Inc., New Orleans, Louisiana
ABSTRACT
This paper describes the use of approximate (simple) and rigorous methods used in configuration development of a deepwater subsea intervention system.
The need exists for various levels of subsea intervention from simple package retrieval and landing, to downhole intervention. All of these services are possible from a semi-submersible drilling vessels, which are significantly more expensive to operate than diver support vessels (DSV's), which in turn are more expensive than support vessels (SV's).
The present work is part of an ongoing effort to establish the range of intervention packages than can be deployed and retrieved from a SV in the Gulf of Mexico in water depths up to 6,000 ft (1,800m). The paper emphasizes dynamic characteristics and configuration development for a heave compensated system planned for sea-trials in 1996.
