MULTIDIAMETER PIGGING – FACTORS （MULTIDIAMETER清管因素）.pdf

MULTI-DIAMETER PIGGING – FACTORS AFFECTING THE DESIGN AND SELECTION OF PIGGING TOOLS FOR MULTI-DIAMETER PIPELINES By Karl Dawson, Pipeline Engineering, Catterick Bridge, Richmond, UK SUMMARY Multi-Diameter Pigging This paper will consider the process involved in pigging tool selection for pipelines with two or more significant internal diameters which require pigging tools capable of negotiating the different internal diameters whilst also carrying out the necessary pipeline cleaning operation. The paper will include an analysis of pipeline features that affect pigging tool selection and then go on to look at other variables that determine the pigging tool design; this will include a step by step guide outlining how the tool is designed, the development of prototype pigs and the importance of testing and validation prior to final deployment in operational pigging programmes. INTRODUCTION For over 35 years Pipeline Engineering has provided pigging solutions for the oil and gas and related pipeline industries. Pipeline Engineering was a forerunner in the development of a reliable dual diameter pigging solution, and continues to advance this technology into multi diameter lines. With a track record of engineered design solutions to dual diameter and related pigging problems, the application of proven techniques together with new and innovative concepts has allowed the development of multi diameter pigs capable of negotiating multiple pipeline diameter changes and geometry conditions, together with specific launch and operational parameters. Historically the need for a pipeline to be of single diameter construction with a constant bore, and bend radii of 5 times the internal diameter, was a requirement of pipeline inspection companies. This was to enable the clearance between their tools and the pipe wall to allow collection of the required data. If a pipeline followed this configuration it