Flexible riser configuration for a FPSO in deep waters

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:194296

Karunakaran, D; Leira, B J ^[1]; Olufsen, A; Nordsve, N T ^[2]

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1. SINTEF Structures and Concrete, Trondheim (Norway)
2. Statoil Research Centre, Trondheim (Norway)

Throughout the world development of oil and gas fields in deep and ultra deep waters is being considered. Floating systems offer an efficient alternative for development of such fields. Flexible risers will in general form an important part of such floating production system. Presently, the flexible risers are designed by application of factor of safety, which is based on experience from laboratory tests, theoretical pipe mechanics and engineering know-how. Generally, it is not based on reliability calculations and risk assessment. Hence it is very important to assess the safety level in current design practice and to aim at a rational and safe design procedure. In this paper, a reliability analysis procedure for flexible riser systems based on a response surface methodology and FORM/SORM methods is outlined. It is applied to a deep water riser system. In this case only a failure criterion at the top end is considered. This location is critical for this riser with respect to Ultimate Limit State (ULS). The results indicate a sufficient safety level for the top end of the riser. However, it is emphasized that this is not a conclusive result with respect to riser safety in general. A more comprehensive study is required to assess the overall safety level for flexible riser systems. Such a study should include a number of different riser configurations and limit states, specifically FLS criteria, to arrive at more general conclusions.

• OSTI ID: 194296
• Report Number(s): CONF-950695--; ISBN 0-7918-1308-8
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
42 ENGINEERING
DESIGN
FAILURE MODE ANALYSIS
MARINE RISERS
NATURAL GAS INDUSTRY
OFFSHORE PLATFORMS
PETROLEUM INDUSTRY
SAFETY ANALYSIS
WATER WAVES
WAVE FORCES