The multi-phase and different composition of gas flows during the development of offshore oil and gas-condensate fields leads to high costs of energy in the system of in-field storage and transportation of well products. The analysis of the existing storage and transportation systems of gas-condensate mixtures shows that the geophysical nature and complexity of the internal structure of the transported fluids must be taken into account when choosing the mode parameters and calculation schemes of the pipelines. High-speed gas lines can be operated in a so-called "dry" mode, in which the liquid is carried along with the gas, the pipeline profile is relatively straight, without ups and downs. In this case, the formation of so-called "stagnant zones" in the pipeline is excluded. However, if the processing depth of the gas does not allow it to be transported in a single-phase state, then the condensing gas factor manifests itself. The hydraulic characteristics of vertical ups and downs on offshore pipelines are complicated, and pipelines are often filled with water and condensate. As a result, the pressure in the pipeline increases and the location of the collection point for condensing gases away from the production site can cause major problems. If we characterize oil and gas-condensate flows as a dynamic system in which alternating structural changes take place, the question of whether these systems are fractal is of great scientific interest. Based on the change in the fractal value, it is possible to diagnose structural changes during the transportation of various systems, including condensing gases in the pipelines. In this article the modes of change of basic parameters of a gas flow (pressure, flow rate and temperature) on various lines of a gas pipeline for the purpose of the producing of diagnostic criterion for revealing of liquid inclusions as a part of transported gas are investigated in this article. It is established, that in the presence of liquid inclusions at movement of gas flows there are the structural changes peculiar to fluid systems, systems which can be identified by variations of fractal dimensions of flowcharacteristics. Studies have shown that the study of the dynamics of structural changes in gas flows can play a role in diagnosing the formation of liquid phase embryos in gas pipelines. For this purpose, diagnostics for the movement of gas streams accompanied by liquid deposits in the pipelines has been proposed.

Pipeline transport is one of the most capital and metal-intensive types of transport. Being environmentally friendly during normal operation, it can cause irreparable damage to nature in case of accidents. Therefore, the issues of reliability and efficiency of operation of field and main oil and gas pipelines and control of energy characteristics during their operation are of no small importance. The amount of additional pressure in the system from hydrodynamic shocks is determined by the density and elasticity of the pumped liquid, as well as the elasticity of the walls of the pipeline itself. The article considers the problem of estimating the critical speed and dynamic loads during the movement of multiphase flows through pipelines, taking into account the interaction of the phases. Dynamic loads are calculated based on the change in critical speed for various structural forms formed as a result of the interaction of phases. These loads, compared to shell structures with separated phases, turned out to be less than when moving in a mold with dispersed bubble structures. The characteristics of the critical speed distribution are determined. It has been determined that the dynamic loads arising in multiphase flows with a predominance of the gas phase are many times higher than in systems where the liquid phase is the leading medium, and the dependence of the pressure distribution on the densities of the phases has been shown. The work analyzes various modes of hydraulic shock. The volume of oil caused by its compression during hydraulic shock was calculated. The results of calculating the increase in the volume of an oil pipeline due to a dynamic impact are presented. Keywords: Critical speed; structural form; speed gradient; density; hydraulic shock; dynamic load; energy feature; elasticity; multiphase flow; flow structure.

Experiences in the production, transportation and preparation of crude oil for transportation have shown that specific problems arise related to their mixing, including water contamination. In recent years, interest in studying these problems has significantly increased, mainly due to the development of extraction technologies for heavy oil samples and bitumen. Along with various difficulties encountered during the pipeline transportation of complex rheological crude oil blended with each other and with light oil, including condensate (such as sedimentation, etc.), imbalances are also observed during storage, as well as in the processes of delivery and reception. During the dehydration of oil mixtures, a synergistic effect is observed in the consumption of demulsifier. The article investigates, in accordance with international standards and based on laboratory tests, how the physico-chemical properties (density, viscosity, freezing point, saturated vapor pressure, chemical composition) of mixtures formed by blending various grades and compositions of Azerbaijani oil examples with each other and with condensate change and how the efficiency of dehydration of oil mixtures is affected by the mixing ratio of the oil involved. It was found that the quality indicators (physico-chemical parameters) of oil mixtures differ non-additively from the initial parameters of the blended products and in some cases, this difference is even observed with anomalies. Moreover, depending on the mixing ratio of the oil, variations in the consumption of demulsifier were also identified.