METHODS OF PIPELINE CONSTRUCTION IN ARCTIC AND SUBARCTIC REGIONS AND APPARATUS FOR CARRYING OUT SAME

摘要

METHODS OF PIPELINE CONSTRUCTION IN ARCTIC AND SUBARCTIC REGIONS AND APPARATUS FOR CARRYING OUT THE SAME Methods of pipeline construction in arctic and subarctic regions and apparatus for carrying out these methods are disclosed. Summer-constructed fabrication yards are established at central locations along the pipeline right-of-way spaced at intervals of 100 to 150 miles each comprising a group of buildings utilized to fabricate instrument , and hermetically cap pipe sections, including quality control, x-ray, hydrostatic testing, external coating, final inspection, and rivet coating and weighting, along with facilities for moving pipe sections from place to place during fabrication, inspection, coating, etc. After fabrication, the pipe sections are stored in a marshalling yard located near the end of the fabrication yard nearest the half-division in which it will be installed. In winter each pipe section is towed to its place of installation over a working snow pad or snow road following the pipeline right-of-way, for instance, by a pair of large tow tractors operating in tandem. Sensors or sensing instruments mounted on or in the pipe section during fabrication are cabled to indicating instruments in the lead tow tractor, to assure that while in transit the pipe section undergoes no bend less than its permissible roped radius of curvature. The forward end of the pipe section being towed is mounted on a nose sled bearing a compressor and air heater for the purpose of maintaining an elevated temperature inside the hermetically sealed pipe section. To prevent "slideouts" or the like, portions of the pipe may be mounted on special "pipe sleds" provided with a lifting means which enable a sideboom tractor to raise a portion of the pipe section or impart a pull to assist in preventing sideslipping. When a pipe section is being moved, a number of sideboom tractors accompany the pipe section, guiding respective portions of it in special roller cradles equipped with remotely controlled pipe-gripping means or brakes.