Fulmar's New Oil Evacuation Route to Norpipe

Abstract This paper describes a major greenfield/brownfield Project on the Shell Expro Fulmar platform which has changed the historic offshore tanker oil evacuation route to a new 24" diameter oil pipeline connected to the Phillips J-Block pipeline and then into the 34" diameter Norpipe system terminating at the Phillips Teesside oil terminal. Focus is on the topside facilities, and the work that had to be carried out on an operational platform within a short time scale, to prepare for new modules, offshore installation, hook-up and commissioning. Construction activity commenced on 28 February 1996 and exactly 10 months later on 1 January 1997 oil export to Norpipe was achieved. In that period 140,000 offshore construction and commissioning man-hours were expended with no lost time, high potential, or environmental incidents. Additionally production deferment from Fulmar and incoming fields, Gannet, Auk and Clyde was minimised. A number of construction and commissioning initiatives were taken in order to maximise onshore construction and minimise offshore construction, and reduce hook-up and commissioning, these are discussed later. All major equipment was installed within two new modules which were onshore fabricated, leaving only essential equipment for brownfield installation. Shell Expro has now successfully completed to schedule or ahead of schedule a number of greenfield/brownfield projects in recent years such as the Brent Redevelopment, Cormorant Alpha/Pelican Project and has built up a wealth of experience and expertise in the management of integrated operations and project activity. Introduction Following the retiral of the Floating Storage Unit (Fulmar FSU) in May 1994, a temporary offshore loading evacuation system has been employed at Fulmar using the STL tanker 'Vinga' and shuttle tanker offtake tankers at circa 5 day intervals. After evaluating a number of offshore loading and pipeline options it was decided in April 1995 to proceed with the pipeline option into the Phillips operated Ekofisk to Teesside pipeline, commonly called Norpipe system. Conceptual design commenced in April 1995 followed by detailed design in October. The Project sub-sea requirements were 16km of new 24" pipeline with associated riser and SSIV facilities. For topsides new pumping, metering and control systems were required which were modularised in a new onshore fabricated Oil Export Module (OEM -700 tonnes) and a Switchgear and Instrumentation Module (SIM -80 tonnes). The Central North Sea (CNS) Oil Evacuation Project will provide a long term oil evacuation route for various Central North Sea oil and gas fields. This oil evacuation route will be through a pipeline connection from the Fulmar Alpha platform to the Phillips operated J-Block/Norpipe oil pipeline system (Reference Figures 1 and 2). Fulmar is a Shell Expro operated offshore fixed oil and gas production and drilling platform located approximately 350 km due east of Dundee, Scotland. The platform has a permanent bridge connection to a fixed, small wellhead jacket, Fulmar AD, to the south of the main platform, reference figure 3. The water depth at the Fulmar platform is 83m. At the tie-in point with the Judy export line the water depth is 73m. (Depth relative to LAT). The main features of the CNS Oil Evacuation Project are:–installation of a 16 km 2411 oil pipeline section from Fulmar to a 'wye' piece on the Judy pipeline to Norpipe (as shown in Figures 1 and 2).–installation of an associated subsea isolation valve (SSIV) for the oil export line.–installation of a 1.2 km 4.5" fuel gas import pipeline section from the Fulmar gas line, complete with a subsea isolation valve.–installation of an oil export riser and two J-tubes on the Fulmar AD jacket.–fuel gas import pipework routed across the bridge to the Fulmar A platform.–Installation of a cantilevered oil export module (OEM), on Fulmar A, west of module, M6 (Figure 4). P. 499^