The Gannet oil export pipeline is operating at relatively low flow rates. At these low flow rates, there is potential to have a flow regime with laminar flow instead of with turbulent flow. Therefore, the viscosity, or rather the rheological properties, of this oil are essential in determining the flow regime. This is even more critical for the routine pigging of the pipeline and for the assessment of wax settling. Wax settling will particularly occur in laminar flow situations where there are no forces to push a settling particle back up.
The Gannet platform is located in Block 21/25 of the central North Sea, approximately 180km east of Aberdeen and 77km from the UK / Norwegian median line in a water depth of approximately 95m. Gannet is the host platform to Gannet A, B, C, D, F and G fields. Gas is exported through the 20" Fulmar Gas Line (FGL) Pipeline to St Fergus, oil and condensate is exported via a 107km, 16" pipeline to the Fulmar A platform. At Fulmar, oil is comingled with liquids from the Fulmar and Clyde Areas and exported into the 24" Fulmar spur line. From there, the fluid flows through the Southern Wye on the Judy Spur, and then into the 34" Norpipe trunkline, which runs some 300km to Teesside. The Fulmar A is approaching Cessation of Production (CoP), and an alternative export route is therefore required. The selected concept is to bypass the Fulmar platform subsea by laying a new section of pipe to extend the oil export pipeline to the Northern Wye on the Judy spur. A new 16" 23km section will extend the pipeline ~2km from the Fulmar platform to a new Gannet Export Wye. The section between the Gannet Export Wye and the existing Northern Wye is 24" and approximately 50m in length. Gannet production will then enter the Judy spur via the Northern Wye to continue onwards to Teeside via the 34" Norpipe trunkline.