The subject for discussion in this paper is the marine operations as they were performed during the research project:
CIB - DRVERLESS INSTALLATION AND MAINTENANCE OF SUBSEA PRODUCTION SYSTEMS IN DEEP WATER
The project commenced in January, 1981, with participation of six oil companies: AGIP, Chevron, Fina, Hispanoil, Norsk Hydro, and Total.
A single-well Subsea Production System (SPS) was installed in 300m of water depth for test purposes in the Onarheimsfjord on the west coast of Norway in the autumn of 1982. Two different ways of connecting flowlines to the SPS were tested; a remote off-bottom pull-in operation featuring the "J"-method.
All operations were performed diverless, a remotely operated observation vehicle (ROV) and an Atmospheric Diving Suit (ADS) being used for general assistsance and back-up.
In order to optimise the operations, extensive analyses had been performed an the equipment and on the operational plan. These analyses included a failure mode and effect analysis (FMEA) on equipment and operations in general as well as computer simulations of the flowline operations.
The objective of the test was to gain experience related to operations in deep water, state limitations in today's level of technology.
The paper gives a review of the test and planning phase. The problems related to deep waters are pin-pointed, and some results are given.
One of the critical phases in subsea field development is connected to marine operations during installation and completion phases. There are high costs involved, and at the same time a strict demand for safe and reliable operation. Subsea Production Systems have so far been installed in water depths where the use of divers has been possible either as a basic feature in the plans or as a means of back-up. Some diveless Subsea Production Systems have been installed in shallow water in order to prepare Production Systems have been installed in shallow water in order to prepare for future requirements.