Abandonment and recovery solution of submarine pipelines

Abandonment and recovery operation of submarine pipelines require a set of design data which enable this operation to be carried out without overstressing the pipeline. In this paper an analytical/ graphical approach is presented for arriving at a solution which meets the above requirement. For the purpose of analysing the pipeline the finite difference method is adopted while the cable length attached to the pipeline is analysed by employing a line integration technique. The analysis is carried out under static forces which also include the effect of current velocity. The results of the analysis of the pipeline are composed into a set of graphical plots from which the initial conditions required for the analysis of the cable length are furnished. Using the above approach the design curves required for the abandonment and recovery operation of a 75 cm O.D. pipeline are obtained. The effect of current velocity on the design curves is also shown through the solved example.