The paper outlines the engineering and testing carried out as part of the BPExploration DISPS Project to develop the technology for a diverless subseaproduction system. It describes the conceptual template design and theprinciples of installing and maintaining the system without the use of divers. The scope of the Template System Testing Programme is discussed and the resultsof the land testing phase are summarised.
It concludes that the land testing carried out so far has been successful inprogressively proving the techniques and principles of a diverless templatesystem.
BP Exploration have a goal of developing the technology to produce hydrocarbonsfrom diverless depths.
Feasibility studies of a diverless subsea production system were carried out in1985 by Fuel Subsea Engineering Ltd in close liaison with BP Engineering. TheDISPS (Diverless Subsea Production System) Project was initiated in 1986 toidentify and develop the principles, techniques and equipment in water depthsbetween 350m - 750m using diverless subsea systems.
The work led to a diverless modular template conceptual design and identifiedsystems and components requiring development and testing in order to achievethe objectives.
As part of the DISPS development, the Template Systems Testing programme isbeing carried out to verify the feasibility of installing and maintaining theequipment on the template without the use of divers. The programme includes thedevelopment of key components that .are an integral part of the developedtemplate design.
This paper summarises the template conceptual design, the test programme andthe results of the land testing conducted to date.
BP's DISPS concept philosophies are based on the following:
Designed for water depths in excess of 350 metres; the design is centeredon 400 metres with a further conceptual understanding of system requirements in750 metres.
All non-structural subsea components should be remotely retrievable eithersingularly or in combinations with other components within modular hardwarepackages.
Retrieval techniques should be carried out without diver intervention.
Maximum practicable utilisation of field proven or state-of-the-artequipment and techniques is required unless requirements dictate otherwise andparticular emphasis is to be placed on reliability and simplicity.
The system should be so designed that components with a relatively highprobability of failure do not, in any failure mode, cause shutdown of more thana single well.
The DISPS concept is based on oil and gas production with or without waterinjection subject to field requirements. The addition of gas lift and chemicalinjection have been evaluated for impact on the design of modules, Xmas trees, manifolds and flowlines.
The DISPS base case design assumes control of individual wells by chokes withpressure and position monitoring on the template and commingled export ofproduct back to a processing facility up to 10 km away. Flowline lay andtie-back techniques have also been considered as part of the DISPS developmentprogramme.