Розвідка та розробка нафтових і газових родовищ 2019. № 2(71)УДК 622.692.4 r u d z @ n u n g . e d u . u a 2 ПАТ "Івано-Франківськгаз"; 76010, м. Івано-Франківськ, вул. Ленкавського, 20, тел. (0342) 586274, e-mail: n a z a r . s l o b o d i a n 2 8 @ g m a i l . c o m

The article deals with modern technical methods of improving the efficiency of gas pipelines cleaning. The most effective method of improving the efficiency of a gas pipeline is its periodical cleaning with mechanical treating units. In practice, a large number of cleaning pistons of various technological designs are used. Regardless of the design, none of them can completely remove the fluid accumulations. The reason for the decrease in efficiency is the presence of fluid in the cavity of the pipeline. The fluid can be of two types – high-viscosity resinous deposits and low-viscosity liquid deposits.  When moving, they perform the role of local resistance. The type of the main gas pipeline purification process is largely determined by the physical properties of the fluid which is being displaced. The authors specify the functional dependence of the velocity distribution in the pipe cross-section while displacing the Newtonian fluid, as well as the value of the initial pressure of the liquid phase on the cleaning piston. The interaction of a purifying device with fluid accumulations having different physical properties is investigated. The authors develop the algorithm of calculating the volume of the flows over a moving boundary into a back-piston space, in relation to their velocity. The dependence of the volume of fluid flows caused by hydraulic shock for Newtonian and non-Newtonian fluids is composed. Based on the calculations, the authors plot the graphical dependence of the correction coefficient on the ratio of dynamic viscosity to the degree of consistency, as well as the dependence of the total flow rate on the speed of movement of the cleaning unit. The formula for calculating the correction coefficient is obtained. The article presents the results of calculating the value of the correction coefficient which takes into account the rheological properties of the fluid. In relation to the properties and rheology of the non-Newtonian fluid, the authors determine the optimal velocity of a treating unit.

The technical and economic aspects of improving the hydraulic efficiency of pipeline transmission are considered. Hydraulic efficiency of gas transmission systems reveals directly their economic efficiency and practicability, as well as the process of "aging" of the main gas pipelines over time. One of the effective methods of improving the hydraulic efficiency of a gas pipeline is its periodical cleaning with the use mechanical cleaning units. The process of cleaning gas transmission systems with cleaning pistons is technologically complicated and expensive. Therefore, when planning, it is necessary to create all the conditions that guarantee maximum cleaning efficiency and are costeffective. The increase of the number of gas pipeline cleanings improves the hydraulic effi-ciency of the systems. It increases the profit of gas transmission organizations. As a result, the cost for cleaning goes up and leads to the decrease of profit of the gas transportation companies. Therefore, the number of clean-ings of gas pipelines and gas transmission systems should be equal to the optimum number of cleanings over a period of time. The indices of economic efficiency of gas pipelines pigging are analyzed. The authors find that a more specific indicator of the evaluation of gas pipeline cleaning procedure is the increase in the total profit of the gas transmission company. The dependence of the gas transmission company profit on the number of gas pipe-line cleaning over a certain period of time is investigated. The method of specifying the optimal periodicity of gas transmission systems cleaning is offered. The mathematical model of the process is constructed. On the basis of the model, a transcendental equation for finding the optimal number of gas transportation system cleanings for a certain lifetime is obtained. A grapho-analytical method for the solution of the equation is offered. Based on the calculations, a graphical dependence of the optimal periodicity of gas transmission systems cleaning is constructed.

An important aspect of improving the hydraulic efficiency of pipeline transport is its periodic cleaning with mechanical cleaning devices. Cleaning gas pipelines with cleaning pistons is a technologically complex process. It is advisable to adjust the speed of the piston to increase the efficiency of cleaning the pipeline with the crossed track profile. On the ascending and plain sections of the route, maintain a high speed of movement of the device, and on the descending it to reduce. To slow down the movement of the piston in the downstream sections of the main gas pipelines, it is proposed to change the technological scheme of the linear part. It is suggested to use a looping connection to change the flow chart. The change of the speed of movement of the treatment device when changing the technological scheme of the main gas pipeline was evaluated. The influence on the dynamics of the movement of the cleaning piston of the main parameters of the pipeline and looping, as well as the parameters of the movement of the piston itself, are investigated. A mathematical model of the process is built, on the basis of the implementation of which the regularities of the treatment device movement when changing the technological scheme of the gas pipeline are established. An equation was obtained to find the ratio of the mass flow rates of gas in the main gas pipeline before and after connecting the loop, which can be solved by the iteration method. The algorithm is developed and the program of calculation of the degree of reduction of the speed of movement of the piston is developed, depending on the kind of technological parameters and technical characteristics of the treatment device and the pipeline. Based on the calculations, the graphical dependences of the relative speed of the piston on the technological parameters and technical characteristics of the main pipeline were constructed. The authors found that the greatest effect on the degree of reduction of the speed of the piston has the length of the loop. It has been investigated that a decrease in the initial pressure and an increase in the final pressure, as well as an increase in the pressure drop at the moving boundary, lead to an improvement in the braking conditions