Oil pipelines systems for hydrocarbons transportation are linear projects that can reach great lengths. For this reason, theirs paths may cross different geological formations, soil types, navigable or torrential waters; and they may face geotechnical and hydrological instability problems such as creeping slopes, geological faults, landslides, scour and differential settling which causes different relative movements between the soil and the pipeline. The OCENSA (Oleoducto Central S.A) 30″ and 36″ diameter system was built in 1997 to transport crude oil from the eastern foothills of the Andes to the Caribbean Coast along some 830 km of the Eastern Andes mountains range and the spurs of the central Andes mountains range of Colombia: it was a major challenge to secure the integrity of the pipeline in the face of natural events.

The Andes Mountains, rich in geographical features and diversity, poses a significant threat to the integrity of oil and gas pipelines due to geohazards. Land movement and unstable soil conditions can trigger changes in the original trajectory of the pipeline resulting in undesired bending strain which can result on failure of the facility. OCENSA – Oleoducto Central S.A. from Colombia assesses the pipeline condition in geotechnical unstable places by comparison of In Line inspection results taking into account pipeline movements and bending strains changes along the zone of study. Bending strains in the pipe are compared against allowable values and emergency values which constitute the criteria to execute mitigation and/or remediation activities that must be done in order to maintain the pipe integrity. To project the pipeline behavior in time, 3D finite element models are developed, allowing the programming of future activities. This paper presents results obtained in a study case to show how pipeline is assessed and how different mitigation activities are developed. Mitigation Techniques such as stress relief procedures and EPS (Expanded Poly-Styrene) blocks incorporations are explained. These techniques are executed in order to reduce the pipe response due to soil displacements during landslide events and creeping slopes, with the final scope of assuring a safe operation.

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The OCENSA pipeline crosses the Valley of the Magdalena river flood on its way to the Caribbean Sea, the area of the valley is commonly inundated during the rainy season on shallow waters that remain flooded swamps. These swamps soils are composed by extremely soft peat with thicknesses greater than 15 meters. In June 2016 started the construction of a highway with an embankment of 6 meters in height which was more than 30 meters away from the OCENSA 30” pipeline, Due to the high compressibility of peat, to construct the road the soil is subjected to a process of consolidation and the height of the embankment was corrected adding more material. In July 29 2016 occurs a failure by load capacity on the ground under the embankment and as a result of this fault a lateral displacement of the adjacent soil producing a horizontal displacement in the pipeline of more than 50 cm. This document shows results from the affectation to the pipe and the measures taken to correct the situation.

Incidents associated with geohazards involving oil and gas pipelines can be avoided in most cases if there is an adequate program for monitoring pipelines, rights of way and triggering agents aimed at prevention. Knowledge about how to manage geohazards is currently dispersed in the operators’ experiences, and it is necessary to compile a guide that will facilitate the selection of the appropriate technology for monitoring pipelines, rights of way and triggering agents. This document explains the development of a project of the Regional Association of Oil, Gas and Biofuels Sector Companies in Latin America and the Caribbean – ARPEL, the deliverable of which will be a practical technical guide for companies operating in Latin America and the Caribbean for which geohazards represent one of the greatest risks to the integrity of oil and gas pipelines.