Repair Strategy to Reduce Operation Service Interruption in a 48' Natural Gas Pipeline

摘要

This paper describes the damage caused by a tropical storm to a 48" gas pipeline considered to be the main natural gas supplier within Mexico's distribution network. Included is a detailed description of the temporary and permanent repairs and rehabilitation carried out. The pipeline section damaged during this natural event is located in a wide water crossing of the river "Tecolutla" in Veracruz, southern Mexico. The construction process to make a new crossing included horizontal drilling using state of the art technology, extensively applied and improved within the industry during the past 10 years. To accomplish the operation, a novel technique was applied, since the pipeline dimensions (48" diameter and 853 m length), required special tools and equipment Only twice before in the world have projects similar to this one been attempted. This was the first ever application in Mexico. Therein lies the uniqueness and importance of its successful completion, despite the logistical problems and unforeseen difficulties that the contractor was presented with, such that at times it appeared that the work would not be successfully completed. The need to keep the pipeline operating during the project caused delays in most of the scheduled activities. A key factor to ensuring a successful end to this project was the contractor selection. Supervision and quality control were also important issues during the project's development. The horizontal drilling approach allowed different arrangements for the pipeline crossing to be assessed. The arrangement chosen avoids the use of a gate valve and a bypass on the right side of the crossing, with the advantage of keeping this pipeline section 7 metres below the riverbed.