U.K. Block 22/11
Landmark: FMC Technologies’ first EPC contract executed in the U.K.
The Shell (Enterprise) Nelson field south satellite development is located in U.K. Block 22/11, due east of Aberdeen, Scotland, and 12 miles (21 km) southeast of the Forties field. The south satellite development is a cluster of subsea trees located around a central subsea manifold in 280 ft (86 m) of water. It is a single-drill-center concept tied back to the Nelson platform, which is 3.5 miles (6 km) to the northwest with flexible pipelines. It is controlled by an electro-hydraulic multiplexed control system. The project began in 1992 with contract award and the drilling of two subsea wells with FMC’s 18-3/4" 10,000 psi UWD-II drilling system. The wellhead protective structures and manifold were installed in 1993, and the first two trees were installed in the first quarter of 1994.
FMC was awarded the contract for the engineering, procurement and construction of all subsea equipment in the south satellite development with the exception of the production controls and the flowlines. FMC provided the wellhead and running tools, the workover control system and umbilical, trees and tree running tools, completion riser, overtrawlable wellhead protective structures and the manifold. The 150-ton manifold was a unique design based on vertically stacked headers and using FMC’s Dynetor® connector to allow fast and easy diver replacement of the production well bay branch valves. The manifold pipework consisted of two 8" super duplex production headers with a super duplex forged wye block. The wye block was one of the largest super duplex forgings made at that time, and the manifold was one of the first to use super duplex in the pipe work. The manifold also had one 8" super duplex production/test header, one 10" carbon steel water-injection header and a 6" carbon steel gas lift header.