Remote metering

March 3, 1999, 08:00 CET

A new metering device being tested by Statoil is the first of its kind which can be installed subsea by remotely-operated vehicle (ROV).

Developed by Fluenta of Bergen in close cooperation with Statoil, this solution was tried out in mid-February with one of the seabed templates on the Statfjord North satellite in the North Sea.

The newly developed sand detector, which uses acoustic signals to measure sand content in the wellstream, was clamped to the choke bridge on well E01. This operation utilised a ROV deployed from Normand Mjolne.

"This test was successful, particularly because sand from the reservoir is very fine," explains production manager Berit Birkeland in the resource management department of Statfjord operations (SF RESU).

"And the fact that we managed to implement the operation during the North Sea winter shows that this solution is robust."

Sand in wellstreams causes wear to production piping and other equipment. Metering has normally been conducted on the platform.

All detection of sand from Statfjord North has so far been carried out when production from several wells is collected on Statfjord C, 17 kilometres away. Metering therefore first takes place 160 minutes after the flow has passed the E01 choke bridge.

"By metering at the wellhead, flow rates can be adjusted to optimise the well in terms of sand content," says staff engineer Raymond Børeng at SF RESU.

"That's because we have better control over possible sand production from each well at all times."

He says the subsea detector will be adopted on the Statfjord satellites to help optimise production from each well. The device is also due to be permanently installed on the Statfjord north flank installations, which will lie about eight kilometres from the C platform.