Norsk Hydro ASA installed downhole for the first time in the world, multiple fibre-optic sensors combined with surface controlled, flow-control components, according to Weatherford International Ltd., the supplier of the intelligent technology.
The sensors in Well E-11 of the North Sea Oseberg East field include pressure and temperature gauges and a distributed temperature sensing line.
These downhole sensor arrays provide data for day-to-day production management and enable strategic reservoir management during the field's life.
Weatherford says the distributed temperature line in Well E-11C lets Norsk Hydro obtain temperature readings every meter, so that it can repeat downhole temperature surveys, and the pressure and temperature gauges provide data from the two producing zones in the reservoir.
One single 1/4-in. fibre-optic line carries the data to surface.
The dual gauges and the termination of the fiber-optic cable are set in the completion string at 3,773 m (12,380 ft) measured depth and at a 73.2° hole deviation, which is just above the liner hanger and 235-m below the 95/8-in. production packer.
The well had an initial downhole pressure of 289 bar (4,290 psi) and a producing temperature of about 125° C. (257° F.)
Weatherford claims that fiber optics have more reliability than the electronic equivalent because of fewer parts, no moving parts, and no downhole electronics.
