ASSESSMENT OF KARST-SUFFUSION HAZARD OF THE CHAYANDA–ESPO OIL PIPELINE IN YAKUTIA

Link for citation: Nechaev D.A., Strokova L.A. Assessment of karst-suffusion hazard of the Chayanda–ESPO oil pipeline in Yakutia. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 7, рр. 78-92. In Rus. The study is relevant due to the need to identify dangerous sections of oil and gas pipelines located in underdeveloped and sparsely populated areas, due to the development of dangerous geological processes. This study aims to assess the intensity and forecast the development of karst-suffusion processes within the pipeline route located in southern Yakutia, and to determine the most significant factors that activate this process. Methods: processing engineering and geological survey data, digitization of geological maps and decoding satellite images to build factor maps that affect the activation of the karst process: geological structure of the route; curvature, slope, surface exposure; map of surface drainage density and density of total tectonic fracturing. We created a map of the density of karst occurrences along the route according to the route survey and data from engineering and geological surveys during construction. We compiled a map of the susceptibility of the route territory to the development of karst-suffusion processes based on the Frequency Ratio method. Results. We carried out a description of the engineering and geological conditions of the pipeline route. To assess the karst-suffusion hazard of the pipeline route, calculations were made of the expected sizes of sinkholes in the base of structures using the method of G.M. Shakhunyants. Using the method of the ratio of particulars, the correlations between factors and foci of karst occurrences along the pipeline route were obtained. The susceptibility map developed on the basis of these results makes it possible to determine specific site boundaries for determining solutions for monitoring the development of the exogenous process and optimizing the pipeline operation processes. Therefore, the application of such methodology can be applied to other extended gas and oil pipelines located in difficult geological conditions.