Significance of seabed interaction on fatigue assessment of steel catenary risers in the touchdown zone

다국어 초록 (Multilingual Abstract)

The challenges involved with fatigue damage assessment of steel catenary riser (SCR) in the touchdown zone (TDZ) are primarily due to the non-linear behaviour of the SCR-seabed interaction, considerable uncertainty in SCR-seabed interaction modelling and geotechnical parameters. The issue of fatigue damage induced by the cyclic movements of the SCR with the seabed has acquired prominence with the touch down point (TDP) interaction in the TDZ. Therefore, the SCR-seabed response is critical for reliable estimation of fatigue life in the TDZ. Various design approaches pertaining to the lateral pipe-soil resistance model are discussed. These techniques have been applied in the finite element model that can be used to analyse the lateral SCR-seabed interaction under hydrodynamic loading. This study investigates the sensitivity of fatigue performance to geotechnical parameters through a parametric study. In this study, global analyses are performed to assess the influence of vertical linear seabed springs, the lateral seabed model and the non-linear seabed model, including trench evolution into seabed, seabed normalised stiffness, re-penetration offset parameter and soil suction resistance ratio, on the fatigue life of SCRs in the TDZ.

참고문헌 (Reference)

• 1 Karunakaran, D., "Weight-optimized SCRs for deepwater harsh environments" 2005
• 2 Nakhaee, A., "Trenching effects on dynamic behavior of a steel catenary riser" 37 : 277-288, 2010
• 3 Oliphant, J., "Trench interaction forces during lateral SCR movement in deepwater clays" 2009
• 4 Palmer, A., "Touchdown indentation of the seabed" 30 : 235-238, 2008
• 5 Pesce, C.P., "The soil rigidity effect in the touchdown boundary-layer of a catenary riser: static problem" 1998
• 6 Bridge, C., "Steel catenary risers-results and conclusions from large scale simulations of seabed interactions" 2002
• 7 Bridge, C., "Steel Catenary Riser Touchdown Point Vertical Interaction Models" 2004
• 8 Clukey, E., "Soil response and stiffness laboratory measurements of SCR pipe/soil interaction" 2008
• 9 Lyons, C., "Soil resistance to lateral sliding of marine pipelines" 1973
• 10 Thethi, R., "Soil interaction effects on simple catenary riser response" 2001
• 11 Morris, D.V., "Self-burial of laterally loaded offshore pipelines in weak sediments" 1988
• 12 Aubeny, C., "Seafloor-riser interaction model" 9 (9): 133-141, 2009
• 13 Aubeny, C., "Seafloor interaction with steel catenary risers" Offshore Research Centre, Texas A&M University, Minerals Management Service, Offshore Technology Research Centre Industry Consortium 2006
• 14 Sen, T.K., "Riser soil interaction in soft clay near the touchdown zone" 2007
• 15 DNV, "Riser fatigue"
• 16 Akpan, U., "Probabilistic fatigue reliability of large diameter steel catenary risers (SCR) for ultra-deepwater operations" 2007
• 17 Jin, J., "Practical design process for flowlines with lateral buckling" 2010
• 18 Bruton, D., "Pipe/soil interaction behavior during lateral buckling, including large-amplitude cyclic displacement tests by the safebuck JIP" 2006
• 19 Burton, D., "Pipe/soil behavior during lateral buckling, including large-amplitude cyclic displacement tests by the safebuck JIP" 2006
• 20 Wagner, D., "Pipe-soil interaction model" 1987
• 21 Cardoso, C., "Pipe-soil interaction behavior for pipelines under large displacements on clay soils-a model for lateral residual friction factor" 2010
• 22 Orcina, "OrcaFlex User Manual"
• 23 Randolph, M., "Non-linear hysteretic seabed model for catenary pipeline contact" 2009
• 24 White, D.J., "Modelling the soil resistance on seabed pipelines during large cycles of lateral movement" 21 : 59-79, 2008
• 25 Hale, J.R., "Modelling pipeline behaviour on clay soils during storms" 1992
• 26 Willis, N.R.T., "Interaction between deepwater catenary risers and a soft seabed: large scale sea trials" 2001
• 27 Langner, C.G., "Fatigue life improvment of steel catenary risers due to self-trenching at the touchdown point" 2003
• 28 Sen, T.K., "Fatigue in deep water steel catenary risers - a probabilistic approach for assessment of risk" 2008
• 29 DNV, "Fatigue design of offshore steel structures"
• 30 Cao, J., "Fatigue analysis technique of deepwater steel catenary risers" 2010
• 31 Nakhaee, A., "Effects of the interaction with the seafloor on the fatigue life of a SCR" 2008
• 32 Elosta, H., "Dynamic response of steel catenary riser using a seabed interaction under random loads" 69 : 34-43, 2013
• 33 Aubeny, C., "Cyclic tests of model pipe in kaolin" 2008
• 34 Aubeny, C., "Collapse loads for cylinder embedded in trench in cohesive soil" 5 (5): 320-325, 2005
• 35 Giertsen, E., "CARISIMA: a catenary riser/soil interaction model for global riser analysis" 2004
• 36 Dunlap, W.A., "Burial of vertically loaded offshore pipelines in weak sediments" 1990
• 37 Leira, B.J., "Analysis guidelines and application of a riser-soil interaction model including trench effects" 2004
• 38 Brennodden, H., "An Energy-based pipe-soil interaction model" 1989
• 39 Sharma, P., "Advances in pipe-soil interaction methodology and application for SCR fatigue design" 2011
• 40 Grealish, F., "Advanced nonlinear analysis methodologies for SCRs" 2007
• 41 Verley, R., "A soil resistance model for pipelines placed on clay soils"
• 42 Hodder, M.S., "A plasticity model for predicting the vertical and lateral behaviour of pipelines in clay soils" 60 (60): 247-263, 2010
• 43 Xia, J., "A parametric design study for a semi/SCR system in northern North Sea" 35 : 1686-1699, 2008
• 44 Hodder, M.S., "3D experiments investigating the interaction of a model SCR with the seabed" 2010