Offshore production from subsea completions is more and more controlled by means of sophisticated electro-hydraulic control systems, which imply the use of underwater make and break electrical connectors.
The growing need of automations due to the maintenance requirements and the extension to greater depths has led to the development of original concepts of such types of automatic connectors.
These developments have included thorough laboratory test under various severe conditions as salt water, pressures up to 2000 psi, low and high temperatures, sand or mud in suspension in the water.
Final qualification of operational prototypes including up to 60 contacts has been obtained during a one year period at sea, by shallow water, were the different sequences of operations have been repeatedly executed and the corrosion problems implied by the high ratio of oxygen at this depth have been examined.
A research program on offshore production in 1000 meters water depth was launched in 1974 by the Group comprising:
Total Compagnie Francaise des Petroles,
Institut Francais du Petrole
Societe Nationale Elf Aquitaine
The scheme adopted involved a production semisubmersible, various underwater equipment, wellheads and manifold.
Seafloor/surface connection was provided by a disconnectable product Yon riser. Remote control of underwater functions required many electrical connections capable of transmitting both information and power.
These connections, which passed through the base of the riser, had to be disconnectable with the riser, and thus required a suitable connector, enabling automatic connection and disconnection, and the remote control of several contacts in an especially severe environment, representing maximum stresses for such a divice (great depth, polluted environment, underwater vegetation etc). Various connectors have been used in the past in attempts to solve this especially difficult problem, but faced with a very specific need, a special project was launched.
Various manufacturers were approached, but only the companies Souriau and Deutsch agreed to participate in developing this connector, each using a distinct technology. The Group's choice fell on the most widespread type of connector, the conductive connector Before building their final prototypes, each manufacturer tested its operation on a mock-up with a few contacts.
The test connectors were required to meet the following specifications:
Mechanical
maximum diameter 10¾ inches,
immersible in 1000 meters water depth,
automatically connectable and disconnectable at the immersion depth,
operation in polluted environment (drilling mud, sand in suspension etc),
impact and corrosion resistance,
satisfactory electrical characteristics in salt water (insulation and continuity),
safety disconnection by simple vertical pull.
Electrical
number of conductors: 60,
service current: 5 A/Contact,
service voltage: 440 V between contacts,
insulation resistance in service :(available in full paper)
Following a market survey, we selected two manufacturers:
Deutsch,
Souriau.
