Published: March 2001 | 5th Annual Offshore West Africa Conference & Exhibition 2001 “Challenges for the Emerging Frontier” | March 21 – 23, 2001 | Abuja, NIGERIA
Abstract
Offshore exploration for oil and gas is being performed in even more challenging waters, with fields being developed in water depths of 2000 metres and greater. To recover hydrocarbons from these depths a number of technical challenges are presented to the designers of riser and off-loading systems. In addition, met-ocean characteristics and relatively low reservoir temperatures also compound the challenges of offshore West of Africa developments.
This paper discusses how Wellstream’s unbonded flexible pipe technology has overcome the challenges of floating production systems to 2000 metres water depth and how its continued development will ensure its incorporation in new pioneering solutions for ultra deep water riser systems. Specifically detailed reference is made to functional design techniques to illustrate the advantages of using hybrid unbonded flexible risers to span the water column.
The low reservoir temperatures typically found in West of Africa fields dictates that temperature management is crucial in order to minimise heat losses from the reservoir to the processing facilities to reduce the risk of wax deposition, hydrate formation and decreased flowing viscosity. Unbonded flexible pipe technology is also well placed to meet these challenges with a selection of flow assurance tools available.
The paper continues with an overview of the unbonded flexible pipe solutions developed by Wellstream to overcome the other deep water challenges associated with large diameter export riser systems. Finally, the paper concludes with an economic appraisal of why flexible pipe systems should be considered a cost effective solution in the overall CAPEX and OPEX of deep water field developments.
Authors:
Tuohy, J., Avery, A., Martin, S.
Justin Tuohy | @pen 