Влияние карста на эксплуатационную надежность нефтепровода. Методы защиты

Abstract

Background Feature of the construction of pipelines in the regions of Eastern Siberia and the Far East is the inability to bypass the territories subject to karst processes. Aims and Objectives To analyze the occurrence of karst processes in the operation of pipelines, to suggest the ways to ensure the sustainability of main pipelines in areas prone to karst. Methods In the process of determining the time collapse regularities the law of rare events (Poisson law) were used; it allows to determine the extent of area affected by the ravages of karst, furthermore, СРIРЕ software based on finite element method in three-dimensional formulation was used to determine the allowable sag limit and the stress level in a pipeline. Results 1. Intensive karst processes leads to the collapse of ground and pipeline sagging, resulting in the formation of zones of pipe increased stress that determines the nature, development and consequences of emergency situations. 2. It was analyzed the influence of different types of karst processes, taking into account the presence of soluble rocks, their mineral composition, fracturing, dissolving power of water, topography, climate, land area on the rate of karst processes; as well as this, it was developed a method of estimating the probability of destruction of the pipeline by karst collapse and achieve the maximum projected radius of the karst funnel. 3. Recommendations for improving the stability of oil pipelines in the area of karst holes, including a methodology of the effectiveness assesment of options to improve the stability of pipelines, which allows to justify the rational parameters of repair and protective of structures to prevent and eliminate karst occurence.