Optimal use of supports in interposing a pipeline into the submerged crossing well. Part 1

Abstract

The paper considers the problem of supports optimal arrangement in pulling a pipeline through the well during construction of the submerged crossing by the directional drilling method. Part 1 of the paper presents results of using the pipeline rod model with the transition section located on fixed supports with the variable lift height. Conditions for optimizing the supports positioning provide for the absence of contact loads at the pipeline inlet into the well and the minimum stresses within the crossing limits, or the minimum supports’ reactions on the section. The number of supports used and the required pipeline height were determined. The influence of the span length between the supports with uniform and non-uniform supports positioning in the drilling fluid presence in the well was evaluated. Effect of tensile or compressive axial force in the pipeline on the supports arrangement was studied. Consequences of one of the supports failure during the pipeline pulling were analyzed. The operating range of the pipeline lifting height on the supports was found according to criterion of the supports coming out from under the load that determines the required pipeline positioning accuracy. According to the calculation results, the pipeline bend shape, the acting stresses diagram and the supports reaction were displayed. With the optimal arrangement of supports, impact on the pipeline during the pulling process is limited to the technologically necessary minimum not affecting the subsequent crossing operation.