NUMERICAL-SIMULATION OF THE PULL-IN OPERATION IN SUBMARINE PIPELINES

'Pull-in' operations consist in the deflect-ion of a pipeline, resting on the seabed, until it is ready to be connected to a subsea oil prod uction structure. This work presents the numerical methods and strateg ies employed in the development of a computational system for the simu lation and analysis of such operations, involving severe geometric non linear effects due to large displacements. The following aspects are a ddressed: representation of the pipeline; anisotropic friction in the soil-pipeline interaction; three-dimensional behaviour, and representa tion of the chain-buoy assembly in 'off-bottom' operations; and the ad equate representation of the pull-in cable. The study of the final con nection to the subsea structure is also addressed. The quality of the numerical simulation obtained from the application of this computation al system is assessed in an illustrative example, where the results ar e compared with those obtained from an experimental small-scale model test. (C) 1997 Elsevier Science Ltd.