U.K. Block 29/2a

Landmark: Horizontal Tree Run from Semi-Submersible Using Extra Landing String

Project Overview

• Contract Award:
  • 1995 (Ph I)
  • 1997 (Ph II)
    
• Sales: Kongsberg, Norway
• Fab. Trees: Dunfermline, U.K.
• Fab. Controls: Kongsberg, Norway
• Service Base: Aberdeen, U.K.
• Host Type: FPSO
• Contract Type: Frame Agreement

Project Characteristics

• No. Trees: 2 (Ph I)
• No. Trees: 2 (Ph II)
• Water Depth: 100 m (330 ft)
• Tree Type: Horizontal
• Tree Pressure: 5,000 psi
• Tree Bore Size: 5"x2"
• Hydrocarbon: Oil

Project Ownership

• CNR 59%
• Shell 27%
• ENI 14%

Scope of Work

Phase I:

• Two (2) horizontal 5"x2" 5,000 psi subsea trees
• AISI 8630 fully inlaid with Inconel 625
• All metal-to-metal sealing tubing hanger
• Vertical wireline access for production bore
• Hydraulic Torus IV tree connector
• Integral tree cap with rigid lockdown
• Diver make-up of flowlines
• UWD-15 wellhead systems

Phase II:

• Two (2) horizontal 5"x2" 5,000 psi subsea trees
• Workover control system
• Integral overtrawlable structure
• UWD-15 wellhead systems
• System integration testing, installation assistance, service and maintenance

Comments

The Banff Field lies 25 km (15 miles) southeast of the Gannet accumulations in the Central North Sea, 200 km (120 miles) east of Aberdeen. It is located predominantly in the ConocoPhillips-operated Block 29/2a, extending into the neighboring Block 22/27a. The field has reserves of about 60 mmbo and approximately 39 bcf of natural gas. The oil will be produced at a rate of 60,000 bopd. The field life is approximately eight years.

The subsea architecture consisted of four (4) horizontal production trees flowing to production manifolds via 4" flexible jumper flowlines. From the manifold, production flowed through a single 6" dynamic riser to a riser platform.

The Banff Field development is the first time the Ramform hull design has been used as a floating production system. The hull, which has a characteristic delta shape, provides both a large-load-bearing capacity (up to 16,000 tons) and a stable work platform, affording a compact alternative to a conventional parallel-sided tanker conversion.