ABSTRACT

Oil industry activity in offshore areas has led to increasing application of subsea production systems. The American Petroleum Institute has formed a new standardization committee to prepare standards for these systems. The first standard, which is currently being finalized, is a Recommended Practice for Design and Operation of Subsea Production Systems. It covers well foundations, wellheads and trees; pipelines and end connections; controls, control lines and control fluids; templates and manifolds; production risers; operations; and quality assurance, materials and corrosion. Other standards in preparation are a Recommended Practice For Flexible Pipe and a Specification For Subsea Wellheads and Trees.

INTRODUCTION

A new API Committee on Standardization of Subsea Production Systems was formed in September 1984 to prepare standards and serve as an industry focal point for questions concerning subsea production systems. This was in response to a general feeling within the industry that standardization work in this area was needed. Starting with the first installation in 1960, there have been 3341 subsea well completions through 1984. Nearly one-half (162) have been made during the 1980-84 period. This accelerating activity along with the extensive experience gained to date makes this work timely. At the present time there are no API standards covering subsea production systems. API Spec 6A2 no longer contains any information about subsea wellhead equipment.

The initial work of the new committee has been the preparation of a Recommended Practice For Design and Operation of Subsea Production Systems. The RP was developed by eight task groups composed of over 60 people representing oil companies, manufacturers, service companies, consultants, and a regulatory agency. As of the writing of this paper (mid January 1986) a composite draft of the RP was being assembled for transmittal to some 50 organizations for review and comment before finalizing the document for publication in late 1986.

Recently, work was begun on the preparation of a Recommended Practice For Flexible Pipe and a Specification For Subsea Wellheads and Trees.

RP: Design & Operation of Subsea Production Systems

This Recommended Practice provides guidelines for the design, installation, operation, repair and abandonment of subsea production systems. It encompasses all system elements (Figure 1), including well foundations, wellheads and trees; pipelines and end connections; controls, control lines and control fluids; templates and manifolds; production risers; operations; and quality assurance, materials and corrosion. The material covering this wide range of equipment and operations is being included in one document to emphasize inter-relationships and the need to consider subsea production installations as systems. The RP consists of the sections discussed in the following paragraphs.

Well Completion Equipment

This section describes equipment and reviews functional and design considerations for the use of subsea wellhead equipment; tubing hangers and trees; and completions on mud1ine suspension equipment. Wellhead equipment includes guidebases, housings, casing hangers, annulus packoff assemblies, bore protectors, wear bushings and running and retrieving tools. Tubing hanger equipment includes both parallel and concentric bore hangers and mechanical and hydraulic running tools. Tree equipment includes connectors, extension subs, valves, TFL components, tree cap and running tools.

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