An overview of current projects in the field of diverless subsea production systems

Abstract

The potential need to produce hydrocarbons from deepwater offshore fields, has created a fundamental requirement to develop highly subsea equipment which can be simply and effectively maintained without the aid of divers Many approaches to diverless maintenance of subsea production facilities have been considered in recent years Those addressed in the paper range from oneatmosphere systems to state-of-the-art deepwater systems currently under development for potential application in the hostile waters of the Northern North Sea, West of Shetlands and elsewhere By overviewing the evolution of subsea production systems it is intended to provide a context into which some of the more highly focused technical papers presented at this session may be placed The paper is presented in four major sections The first is a history of the evolution of subsea production systems up to the first major milestones in dry one atmosphere systems (Garoupa Field development) and in wet hyperbaric systems (Central Cormorant UMC) The second section catalogues the large number of current projects and outlines principal features and common objectives The third and fourth sections concentrate on subsea manifolds/templates which form the hub of most proposed deepwater developments A methodology is proposed by which they may be designed in a logical way and the three key stages of the process are explored These are the development of a basis of design, the selection of the maintenance intervention systems and the analysis of reliability and production availability Representative subsea manifolds/templates are compared in the fourth section to illustrate the effects of the decisions taken during design on the template layout and methods of operation and maintenance.