A laser measuring system with two optically inverted channels

Abstract

Oil and gas pipelines may be subject to considerable deforming loads in use, so a line should be considered as a long item with very deep (extended) hole, and the most promising means of monitoring the position of the axes is provided by a laser system with two optically reversed channels (LS TORC). The paper discusses the features, forms, and types of LS TORC, with a classification and a description of the working principle, together with the purpose and the areas of application. A block diagram is given of an LS TORC for monitoring a long tube. Two types of measurement transducer are considered, which provide for reproducing the actual position of the axis of the hole and the profile of the inner surface. Mathematical models for the measurements are presented. A method can allow one to characterize completely the geometrical parameters of an extended pipeline and determine the optimal section, the points where deflections arise, and points of deformation. The system provides a complete characterization of a pipeline over long monitored regions (up to hundreds of meters).