Due to the importance for the Oil and Gas Industry to have a technical document that consolidates the knowledge on management of geohazards for Latin America, the Geotechnics Project Team (EPGEO under its acronym in Spanish) of the Regional Association of Oil, Gas and Biofuels Sector Companies in Latin America and the Caribbean (ARPEL) developed the “Guidelines for Monitoring and Inspection of Pipeline Integrity Management to Face Geohazards” between 2014 and 2016. These guidelines contain the experience of the different operators in the region, given the highly-complex geological-geotechnical pipeline routes (due to the mountain range of the Andes in South America or the Central System in Central America), as well as the high technical requirement derived from the dynamics of the triggering agents in equatorial and tropical areas. In this respect, this document presents the main results of such consolidation and its dissemination, some relevant aspects to be taken into account in interdisciplinary works with reference to third parties, as well as the new guidelines that the EPGEO has proposed to develop that complement the management of geohazards in a Pipeline Transportation System (PTS).

The Camisea Pipeline Transport System [“Sistema de Transporte por Ductos”] consists of two parallel pipelines, one of which carries natural gas (NG) over a distance of 730 km, and the other which carries liquid natural gas (LNG) over a distance of 560 km, starting in the Amazon basin in Malvinas (Cusco). The LNG pipeline ends in Playa Lobería (ICA) and the NG pipeline ends at the City Gate located in Lurín (Lima). In terms of complexity, the geographic, geological, and climate-related characteristics of the rain-forest, mountain, and coastal regions through which the pipeline passes set it apart from the rest of the world’s pipelines. The highest point in the area is 4,860 meters above mean sea level in its mountain portion in the Peruvian Andes. The first 200 km, which pose the greatest operational challenges, are characterized by residual soils, slopes steeper than 45°, and rainfall of more than 6,000 mm per year — in addition to the logistical difficulties presented by the lack of vehicular access for the transport of personnel, materials, and equipment, such that maintenance work must be done by helicopter. The purpose of this article is to illustrate the diversity of geotechnical scenarios in this geographical area, and to discuss the early identification of risks through the management and control cycle for geotechnical threats, which consists of the following stages: • The Threat Identification System: This stage includes the continuous monitoring of the right-of-way in order to detect geotechnical problems, which are triggered primarily by rainfall. • Risk assessment: This stage involves the use of a geotechnical risk matrix that was developed in accordance with the so-called “Safety Ratio” [“Relación de Seguridad”] , which assimilates the parameters for the calculation of the Safety Factor used in slope stability analysis, thereby making it possible to establish the various risk levels. • Structure design: Depending on the risk level, the corresponding engineering tasks are developed and prioritized in order to determine the designs, through the use of geotechnical engineering processes such as subsurface exploration, laboratory tests, mathematical modeling, and instrumentation. • Implementation of the structures: The geotechnical stabilization structures are built during the dry season, i.e., from April to October of each year. • Monitoring and surveillance: Once the stabilization structures have been built and the dry season has ended, continuous monitoring is performed during the rainy season (November to April), through ongoing inspections, topographic monitoring, and instrumentation at sensitive sites, using inclinometers, piezometers, and strain gauges. Thanks to these working techniques and control measures, as implemented in an area with special topographic and climate-related characteristics, it has been possible to achieve a dramatic reduction in the geotechnical risks to which the Camisea transport system is exposed.

In February 2009 a pipeline rupture occurred along a sloped section of the Oleoducto de Crudos Pesados (OCP) Ecuador S.A. pipeline. The spill resulted in crude oil flowing down the hillside and into the Rio Santa Rosa. Post rupture investigations were initiated to identify the geotechnical factors that may have contributed to the incident and what mitigation may be necessary to ensure future pipeline integrity. The investigation consisted of several activities including detailed site reconnaissance by a geotechnical engineering team and installation of slope inclinometers to assess ground movements. The intent of the slope inclinometers was to determine the depth, areal extent and rate of ground movement, if any. The post rupture site reconnaissance identified a number of terrain features consistent with shallow ground movement mechanisms. The presence of hummocky terrain could be the result of ground movement or an artifact of the use of the slope as cattle pasture. Five slope inclinometers were installed to assess the slope movements within the project site. Four slope indicators were installed up-slope of the pipeline right-of-way to provide some lateral boundary to the ground movement area. The slope inclinometers showed that in the months following the pipeline rupture the terrain upslope of the pipeline right-of-way was moving at a relative constant rate of about 0.45 mm/day. As a result of the geotechnical investigations an integrity mitigation plan was developed. This included ongoing slope movement monitoring, regular site reconnaissance and placement of the pipeline above ground on “sleepers” to isolate the pipeline from the underlying creeping slope. To-date, these mitigations have been successful in reducing strain on the pipeline.