How to design pipe fittings for use in subsea pipelines

摘要

A method for determining a wall thickness of a pipe joint used in an undersea pipeline, the method comprising: i) determining an inner diameter of the pipe joint; and ii) determining a minimum allowable hydrostatic pressure of a depth at which the pipe joint is used. And iii) determining a target wall thickness of the pipe joint, wherein the target wall thickness corresponds to the inner diameter and the minimum allowable hydrostatic pressure, and iv) a plurality having the inner diameter and the target wall thickness. And v) performing an external pressure collapse test that yields data representing hydrostatic collapse pressures at which multiple spare pipe fittings collapse, and vi) a statistical tail derived from extreme value theory. Determining a probability distribution corresponding to the data based on a model, vii) determining a hydrostatic collapse pressure that occurs with a probability of 10-5 or less from the probability distribution, and viii) the inner diameter and the above Determining the wall thickness of the pipe fitting corresponding to the hydrostatic collapse pressure. [Selection diagram] Fig. 6