A numerical study on the feasibility of a cable and pipeline decommissioning device

Abstract

The decommission of cables or pipelines is a vital aspect which ensures a sustainable and effective process of the infrastructure life cycle. Ideally, all offshore installations and equipment should be removed entirely but, in some cases, some flexibility is provided by the international (or national) laws or regulations whether the total removal might induce extreme risk, cost, or adverse environmental damage. The development of technology that facilitates pipeline or cable decommissioning is of vital importance. A newly developed concept of a decommissioning tool has just proposed by Enersea. This novel tool is placed into the pipeline (or over the cables) and induces vibrations in the structure and the surrounding soils, which result in a lower uplift resistance of the pipeline or cable. This paper presents the feasibility study of this technique for a cable/pipeline buried in sand. It is illustrated if it is possible to induce soil liquefaction in the vicinity of the buried pipeline/ca-ble, and the length of the pipeline affected by the liquefiable zone is also presented.