Conversion Of The "Deepsea Pioneer"

ABSTRACT This paper describes the conversion of an Aker H3-AC semi -submersible rig 'Deepsea Saga' to the Floating Production Facility (FPF) 'Deepsea Pioneer', for use on Hamilton Brothers' Argyll and Duncan Fields in the North Sea. The conversion, part of the Duncan Field Development, was carried out within a very short timescale, and completed in 1984. Following the original Argyll FPF, 'Transworld 58', the 'Deepsea Pioneer' represented Hamilton's 2nd generation FPF in the North Sea. INTRODUCTION The Argyll field came on stream in 1975, representing the first oil production from the UK sector of the North Sea. Developed by Hamilton Brothers Oil and Gas as operator, the field, located in Block 30/24 of the UK Continental Shelf (UKCS), pioneered the use of a FPF in the North Sea. Partners in the Block are: Blackfriars Oil and Gas Ltd; Hamilton Brothers Petroleum Corporation; Hamilton Oil GB plc; Kleinwort Benson Energy Ltd; RTZ Oil and Gas Ltd; and Texaco North Sea UK Co. The Argyll area comprises a complex geographical regime and as a result of continuing appraisal two oil-bearing structures, later named the Duncan field, were discovered some four miles West of Argyll in 1980 and 1981. Phase 1 of the Duncan development plan brought the fie1d on stream in 1983, by the use of a sub sea manifo1d tied back over a distance of 3½ miles to the existing Argyll Field Floating Production Facility (FPF), 'Transworld 58'. Phase 2 required the provision of a water injection programme for reservoir management and pressure maintenance. Due to payload limitations, it was not possible to achieve this by adding suitable facilities to the existing FPF. This led to the conversion of the H3-AC semi-submersible 'Deepsea Saga' to meet the totally Argyll/Duncan production requirements. (Fig 1.) The project to modify the drilling rig 'Deepsea Saga' 1nto the FPF, 'Deepsea Pioneer' utilized a 'fast-track' approach, with a 6 month conversion period from start of work to departure for the Argyll F1eld. Detailed design engineering commenced on 12th December 1983, and first oil was produced on 20th November 1984. This paper discusses the key elements of the FPF conversion project, including:–Field and production requirement–The choice of the FPF–Aspects of the design - selection of conversion contractor and site–Conversion Programme Considerations–Certification and classification FIELD AND PRODUCTION REQUIREMENTS The basic process specification for the new FPF was determined to be: -WELL FLUID SEPARATION - The process system to be capable of handling 70,000 B/D of fluids and 14 million scfd of gas. The separation plant to consist of a single train with two stages of separation. A test separator to allow individual wells to be flow tested. The design to provide for 40,000 B/D of oil to be produced and exported via an SBM to a shuttle tanker.