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What We Do Project Data Total Nuggets Field Development
Project : Nuggets Field Development
Client: |
TOTAL EXPLORATION & PRODUCTION UK plc |
Operator/End User: |
TOTAL EXPLORATION & PRODUCTION UK plc |
Date: |
1999 - 2000 |
Project Description : |
Progressive subsea development of four separate oil fields |
Location : |
Northern North Sea |
Services Provided : |
Front End Engineering, ITT preparation. |
Detailed Description :
Background
Nuggets are four small gas accumulations stretching over several blocks of UK Quadrant 3, approximately halfway between Alwyn North and Frigg .The water depth ranges from 110 to 125m. TOTALFINA intend to develop the field as a subsea tie-back to the North Alwyn platform with control from the Dunbar platform. The gas accumulations are to be developed sequentially stepping out to a final distance of 70km from the North Alwyn platform.
North Nuggets lies approximately 40km south of the Alwyn platform field and 19km south-south-east of the Dunbar platform. The Feeder Fiche field is adjacent to the North Nuggets field with the West and South Nuggets field lying 13 and 26km south of North Nuggets respectively.
The gas is relatively dry (maximum 1000 b/w per MMSCM). And contains approximately 98% methane. The oil rim is thick oil (20°API). No artificial lift is required to assist production of the gas. There is no evidence of H2S and only 0.15% of CO2.
Services provided
ode undertook the front-end engineering scope and ITT preparation for the subsea facilities. This included preparation of functional design specifications and all drawings.
- Design of subsea well systems, subsea manifold/cluster, all flowlines and control systems
- Design of topsides MCS, HPU, EPU and UPS
- Umbilical design and installation philosophy
- Development of hydrate mitigation and chemical injection philosophy utilising subsea IRCD’s
- Subsea metering philosophy
- Evaluation of hydrate inhibitor performance
- Material selection philosophy
- Insulation requirements
- Definition of operations and workover interfaces
- HUC and start-up and workover philosophy
Development Scenario
The Nuggets clusters are developed following the philosophy detailed below
Phase 1
- Installation of North Nuggets manifold for 2 North Nuggets wells and 2 Feeder Fiche wells.
- Installation of 40km 12” production pipeline and 3” piggy back (MEG or methanol) pipeline to North Alwyn
- Installation of control and chemical injection umbilical to Dunbar
- Drill and tie-back wells to North Nuggets manifold
- Modify North Alwyn and Dunbar topsides for control and chemical injection functions
Phase 2
- Installation of West and South Nuggets manifold
- Extend 12” production pipeline and 3” MEG piggyback pipeline and umbilical to the South manifold via the West manifold.
- Drill and tie-back two wells to the South Nuggets manifold
Phase 3
- Drill and tie-back two wells to the West Nuggets manifold
Production Issues
The selected facility option utilises a number of production techniques.
- Subsea facility design to optimise installation schedule
- Continuous operation within the hydrate formation envelope (uninhibited)
- Subsea chemical distribution at each manifold utilising IRCD’s
- Combined MEG/methanol for hydrate mitigation
- Control from North Alwyn via Dunbar using existing FO link
- Evaluation of flow regimes to establish operating envelope to minimise slug arrival at North Alwyn
- Continuous hydrate inhibitor injection to remove requirement for expensive pipe in pipe insulation
- Wet gas metering at each wellhead with correlation adjustment for watercut prediction
- Sand detection at each wellhead.
The Nuggets field is one of the longest subsea step-outs currently under development in the North Sea.
