Gazovaya promyshlennost’ № 01 2018

The article presents the experience of Gazprom Neft PJSC in improvement of quality and efficiency of the gas business production processes by upgrading the equipment, reducing operational costs and rising the profitability of the facilities. By 2019, the average level of utilization of associated petroleum gas in the company is forecasted to increase to 92 %. The factors causing complications in the operation of equipment and gas utilization systems were analyzed for each key component of the gas balance system (from gas production to gas processing). The key technological challenges, requiring solutions in the medium and long term, are determined. The detailed classification of technologies for the use of hydrocarbon gases is presented. Data on the world experience in the synthesis of liquid hydrocarbons from associated petroleum gas are summarized. The level of development of gas-to-liquid technologies and their availability for implementation by global companies is estimated. The authors present data on pilot industrial tests of mobile compressor units of different manufacturers with the aim of solving the technological challenge for gas compression. At present, the technology of compressing gas and its transport to consumer is the main one in Gazprom Neft PJSC, while the technology of electrical generation for its own needs takes second place. Based on the trend of scientific and technical development of gas utilization systems, a forecast about the predominance of developments in the field of creation of technologies for gas processing in the field was made for the next ten years. The company plans to develop its own technologies in gas chemistry, gas preparation and compression.

The article presents the Russian experience of creating a project of manifold and subsea template for gas gathering system that is a part of subsea production complex. The assigned task is being solved for the first time within the framework of an import substitution program of Gazprom PJSC. The relevance of the research is due to the fact that the only subsea production system currently in use in Russia was designed and manufactured abroad. The implementation of all planned stages of work will reduce the risks associated with economic sanctions. A manifold with operating pressure of 34.5 MPa is designed; the weight of samples is 350 t and the dimensions are 25.5 × 12.5 × 19.5 m. The possibility of technical compatibility with equipment of foreign manufacturers is taken into consideration. Subsea template with pile type foundation was selected as a basis for the manifold. The requirement for 1 degree leveling is achieved only due to the design of the basis. The precise positioning of the manifold is provided at the final stage of its descent to the foundation. The relevant issues for each stage of the life cycle of the equipment, from manufacturing to dismantling, are considered. It is projected to acquire new technologies and materials necessary for operation in conditions of subsea production. In particular, it is planned to manufacture equipment designed of 25 Cr Super Duplex steel. It is decided to include hydrostatic tests (up to 105 MPa) in the testing program of the manifold and subsea template. Installation of the subsea production system at the field will save the capital costs by reducing the development and manufacturing costs of the equipment. For the fulfillment of the task, it is proposed to standardize decisions and technologies, as well as the use of modular structures.

The identification of risk factors and uncertainties at the earliest stages of implementing projects in the gas industry is the relevant objective. The approach to risk assessment in conditions of multivariate calculations of the project efficiency parameters at the stage of conceptual design of gas industry facilities was proposed and implemented by INSTITUTE YUZHNIIGIPROGAZ PJSC. The sequence of stages of implementation of this approach is presented. The principle of the method is represented on the example of risk assessment related to the accident and causing excessive environmental damage in the process of construction and operation of an underwater crossing over the Ob Bay (Yamalo-Nenets Autonomous Okrug, Russian Federation). The relationship between the risk factors is described, the consequences of the implementation of risk events are given for each factor. An analysis with the substantiation of the probability of occurrence, consequences and damage is carried out for each factor. A quantitative risk analysis was performed using the Monte Carlo simulation method. The analysis makes it possible to interpret the obtain results, presenting them in the form of a probability distribution of project performance indicators in the case of the risk event instance. The proposed approach to risk assessment of gas industry facilities in conditions of multivariate calculations of performance indicators is implemented in the form of creation of the information base for assessment the consequences from the implementation of risks and further accounting for sources of hazardous events.

The article shows that the underground gas storages considerably improve reliability of gas supply, allowing to provide consumers irrespective of season, temperature fluctuations and other circumstances. Two versions of gas consumption are considered. First is for the countries with the expressed seasonal irregularity of gas consumption, where the need to create underground gas storages is proved. The second is for the countries with the irregularity of gas consumption, caused by market condition or quasi-uniform gas consumption, with the absence of significant temperature fluctuations during the year when the need to create reserves of gas is not obvious. For assessment of unevenness of gas consumption and substantiation of necessity of creation of the underground gas storages, the following indicators are used in Russian practice: the coefficient of irregularity of gas consumption, the volume of irregularity of gas consumption; the relative irregularity. These indicators were calculated at the first analysis stage of the actual gas consumption of the three consumers from Russia and four consumers from Venezuela. It is determined that these indicators, especially the components of the marginal values, cannot always unambiguously confirm the necessity of gas volumes reserving. The substantiation of establishment and determination of the operation mode of storages for the countries with warm climate is a more complex task. The based on the harmonic or spectral analysis is presented in the article for its solution. The obtained results allow recommending the use of the spectral analysis based on the Fourier discrete transformation for solving problems of analysis of gas consumption, substantiation the need for creating and defining the type of underground storage that will allow to optimize the technological parameters of exploitation and to minimize capital investment in the construction of underground gas storages.

The article substantiates the methodology for assessing the necessity and practicability of installing the systems of automatic monitoring of technical condition of oil and gas pipelines. The effectiveness of the monitoring system is assessed taking into account the probability of the pipeline transition to each of the possible limit states determined according to the predeveloped classification. The assessment is based on the main parameters, including the probability of detecting the pipeline state preceding the emergency failure; the probability of performing corrective actions based on the monitoring data; decreasing the level of man-made risk; decreasing the probability of an emergency failure; effective cost of the monitoring system, etc. An expression for calculating the criterion of assessment of the monitoring system installation necessity Kсм is presented. It is calculated as the ratio of risk reduction due to the system installation to the value of the system's efficient cost. The implementation of the automatic monitoring system is relevant for Kсм ≥ 1. The application of this system according to risk-oriented approach in the state supervision of hazardous production facilities, in particular oil and gas pipelines, seems relevant and effective solution. It is emphasized that the assessment of man-made risks by the proposed methodology should be carried out separately for each stage of life cycle of a pipeline, including construction, commissioning, operation, and decommissioning.

The special aspects of use of the VNII NP 50-1-4U TURBO SHT-32 essential oil based on the thermally stable dioctyl sebacate in the oil systems of gas compressor units are considered in comparison with traditionally used hydrocarbon oils. During operation of processing equipment at compressor stations, the operation of gas compressor units alternates with their inactivity. At this time, the oil in the untight oil tank is in contact with the external environment, it is exposed to the negative effects of external factors. This research was conducted due to the complaints from operators of gas compressor equipment for the sharp increase in the acid number of essential oil when gas compressor unit is inactive. The processes arising during the gas compressor unit operation under real conditions of the compressor station are modeled in the laboratory conditions. The results of a laboratory experiment of the modeling of the water exposure (in the form of a liquid phase) on essential oil at high temperature are presented for various time periods. The results obtained during laboratory modeling of use of essential and hydrocarbon oils, taking into account the inactivity of equipment, are presented. The experimental data obtained in the laboratory conditions qualitatively coincide with the results of use, which were observed in the conditions of compressor stations. It is determined, that the increase in acid number of the oil, when the unit is inactive, is explained by the fact that partially oxidized oil underwent accelerated hydrolysis. The toxicological aspects of the use of essential and hydrocarbon oils are considered. The conclusion about the inexpedience of the essential oils using for operation of the technological equipment of Gazprom PJSC is made.

The directions of activity development in the field of energy efficiency improvement of Gazprom PJSC are determined in the Concept of Energy Saving and Enhancing the Energy Efficiency of Gazprom PJSC for 2011–2020. The system organization of technological operation modes of main gas pipelines to reduce consumption and losses of natural gas is among the main directions of energy saving in the main gas transportation. The reduction in losses in the gas transportation system is important first of all in solving the problems associated with the requirement to increase the energy efficiency of natural gas transportation. The compressor stations annually emitting large volumes of methane into the atmosphere are a significant source of atmospheric pollution at gas transport facilities. The gas pumping unit is the main and most active source of emissions. Gas pumping units at compressor stations provide compression of gas and its transportation through main gas pipelines. Operation of gas pumping units requires the natural gas consumption for fuel and technological needs. The pressure rises from 5.4 to 7.4 MPa during gas compression in a centrifugal compressor. The construction of centrifugal compressor must have a hydraulic oil-gas seal in order to prevent gas escaping from the internal chamber into the engine room. The special feature of this seal is the discharge of gas from the degassing chamber through a candle into the atmosphere. The article presents the results of experimental determination of irrational losses of natural gas from the degassing chamber of centrifugal compressors of gas pumping aggregates of GTK-10M type Rekon. A mathematical model for calculation of gas losses through candles of the degassing chamber is presented, taking into account the centrifugal compressor working time after the overhaul, the maitenance factor and the volume concentration of methane in the candle.