Unprovoked Errors in Geotechnical Monitoring Activities in an RoW

Abstract

The Camisea Pipeline Transmission System (PTS), owned by Transportadora de Gas del Perú (TgP) in Peru, consists of two parallel pipelines, a Natural Gas (NG) pipeline and a Liquefied Natural Gas (LNG) pipeline. The NG pipeline is 834 km in length, including a 105 km loop. The LNG pipeline is 557 km in length. The first 210 km, are defined as having Amazonian geotechnical characteristics, with the presence of sedimentary and metamorphic rocks and a deposit of materials that are easily altered, which are associated with the transition between the Amazon plain and the Andes mountains. The area between km 210 and km 420 is defined as a mountainous sector with materials having better mechanical properties while the section between km 420 and km 730 located in the coastal sector and has erosive processes such as those associated with wind erosion, seismic activity, alluvial deposits, etc. Due to the variety of geological and geotechnical circumstances of the TgP’s RoW, its PTS incorporates many types of geotechnical monitoring in order to maintain and increase the reliability and integrity of the system. In several sectors not all of the types of monitoring are applicable. Some types of monitoring are: inclinometers and piezometers, aerial surveillance, patrolling, strain gauges (SG), topographic, GIS images (satellite, laser, radar, etc.), culverts, geotechnical optical fiber, accelerometer stations, etc. This article describes some unprovoked errors that can occur in a complex operation (in terms of logistics, geological, geotechnical and socially), in the development of geotechnical monitoring activities of an RoW. Some of the errors that can occur are: • Unacceptable photographic record through aerial surveillance; • Damage to the coating during topographic verification; • Field reports with incorrect data; • Incorrect SG records; • Improper placement of equipment over the pipeline; • Incorrect records in the GIS database; • Errors in the topographical record; and • Inexperience of monitoring staff, etc. However, occurrence of the above-mentioned errors has been lessened through improved operating procedures. These procedures are based on discussions from the various “lessons learned” sessions, which improved: • the appropriate recording of conditions identified in the field; • the labor climate; • crosswise communication between the different areas; and • the preventive approach within the operation of the PTS.