ORIGIN OF EMERGENCY SITUATIONS IN THE GAS WELL FLOWLINE AS HYDRATE FORMATION RESULT

Abstract

One of the main problems in oil and gas transportation industry is to ensure continuity of supply. Ukrainian gas industry today is the leading sector of the energy sector and the gas transportation system, its core which solves two main tasks: to provide natural gas to domestic and industrial consumers and households and increasing domestic production. Gas hydrates formed at high pressures and low temperatures resulting in physical combination of water molecules and certain small molecules of liquid hydrocarbons, gas hydrates under occlusion industrial pipelines usually occurs in autumn and winter. The object of research is selected abortions line gas wells. We analyzed the temperature distribution in the whole region, and found that the warmest area in the eastern region is Lugansk region, and coldest one is Sumy region. The number of fields in all regions is calculated, averaged temperature of the year for oil and gas regions with the highest risk of hydrate cork is presented. Basically, freezing soil of this region ranges from 0.7 to 1.5 m the surface of the soil. For regulatory rules the depth of flow line is 0.8 -1 m. In some cases, 0.6 m is permitted if there is no passage of pipeline transport. Thus, the focus should be given to decreasing temperature at such depths. The structure of the Eastern oil and gas region is designed. The theoretical and actual distribution of ambient temperature and the temperature distribution of the soil with the change of depth are defined. For oil and gas structures cyclic loading is carried out by stresses below the yield strength limit of the material. In this case, the presence of stress concentration leads to a strong increase in local stress cycle and determines the level of fatigue life of the pipeline. Stress concentration factor is calculated for defects of various geometric shapes. It is shown that the stress in the wall of the pipeline in areas of deep corrosion defects more than 1.243- 3.696 times higher than in regulatory documents. Based on the data, load range for corrosion and mechanical tests is selected. The results of fatigue and corrosion fatigue test samples of steel pipe 20 recorded decrease in durability when tested in air up to 25 % in the corrosive environment up to 15 %.