Gazovaya promyshlennost’ № 06 2022

Most oil and gas fields in the Uzbekistan are at the final stage of development, with declining component recovery and final recovery factors and increased risk of additional development, which leads to considerable economic costs. This is the case for the South Kemachi oil, gas, and condensate field in Bukhara Region, Uzbekistan, which has a range of process complications mainly related to production decline. The existing issues include flow rate decline and water entry to vertical gas-producing wells, corrosion wear of tubing and other downhole equipment, low reservoir pressure in the pool, the difference between the actual and design performance due to the decline in the component recovery of the pay formations, non-profitability of the additional development base case. The potential condensate content in the produced gas is almost halved in the pool. To resolve these issues, it is considered to introduce horizontal wells into the South Kemachi oil, gas, and condensate field development system in 2022 by side-tracking the vertical wells existing in the stock. Importantly, in this study, the possibility of using horizontal wells to develop gas-saturated pay formations in this field is considered for the first time. The aims and objectives lie in the feasibility study and selection of the recommended additional development case to ensure enhanced component recovery of South Kemachi and the highest profitability. A rational case is proposed to facilitate the maximum hydrocarbon recovery at the minimum capital and operational expenditures and production cost price.

Nowadays, block-modular gas heaters are becoming more common in construction and reconstruction of gas distribution stations. The key advantage of these heating systems is high energy efficiency due to the use of technical means and materials with optimal operational factors. The disadvantages of such units include the complexity of the design which involves the use of individual components, which are technological products of complete factory readiness, as well as a significant saturation of electronic and electrical components. As a result, it is increased the vulnerability of equipment under the influence of negative factors, as well as the probability of failures and breakdowns. Natural gas heaters, in which the main technological units are made according to the classical scheme (in a common housing filled with an intermediate heat-transfer agent), may be an alternative to block-modular gas heating systems. The intensification of the heating process can be achieved by optimizing the design of the heat generator and gas heat exchanger, modernizing the burners, as well as using high-quality thermal insulation, which will ensure the efficiency of operation at the level of modern systems with significantly superior reliability and safety of operation.

This article presents an analysis of the effect of symmetrical changes in the variogram parameters on the quality of the 3D net-to-gross cube. The object of the study is the gas pool of the field in the Yamalo-Nenets Autonomous Okrug at the geological prospecting stage. Due to its flexibility, convenience, and accuracy, geological and hydrodynamic modeling is essential in oil and gas field development. One of the most important stages in developing a geological model is the calculation of a net-to-gross ratio (development of 3D lithology cube) or facies modeling. At this stage, the entire thickness of the reservoir is divided into different lithotypes. If the reservoir’s size is considerable, then the corresponding rocks are distinguished according to the sedimentation environment, but primarily, at this stage, rocks are divided into two types of facies – reservoir (sandstone, limestone, etc.) and non-reservoir (clay). There are two modeling methods – deterministic and stochastic. In this study, due to the small number of wells, the method of stochastic indicator modeling and its basic variogram analysis have been chosen. The optimal variogram was determined according to the basic parameters and using the variogram map in Petrel (Schlumberger Limited). Increasing the accuracy of the variogram selection has always been challenging, so it is necessary to perform a sensitivity analysis of the variogram input parameters to study the changes in the final results. In this study, key variogram parameters (radius, threshold, and nugget effect) were varied symmetrically. It was concluded that each parameter affects the net-to-gross ratio distribution in the model.

A major contributor to global warming is considered to be the significant emissions of greenhouse gases, primarily CO₂, including those emitted by gas turbine engines and power plants. The reduction of carbon dioxide levels by developing a set of structural measures in the combustion chamber is one of the urgent tasks of engine construction which requires a solution in order to meet modern environmental requirements for gas turbine engines serving as blower drives for gas compressor units.
The presented research is dedicated to the analysis of influence of changes in combustion chamber design on reduction of CO₂ level in exhaust gases of gas turbine engine NK-16ST. Several modifications of the combustion chamber are considered. The first one was a serial combustion chamber with diffusion combustion, the second one was a modernized combustion chamber with a modified front device and converging burners, and the third one with a reduced volume of the flame tube. Each of the chambers considered was tested as part of the engine. During the study, combustion products were sampled directly in the exhaust shaft and their concentrations, including the CO₂ content, were determined.
As a result of this work, it was confirmed that there is a possibility to reduce the concentration of CO₂ in the engine combustion products up to 20 % without affecting the engine parameters. This reduction in carbon dioxide content was made possible by reducing the completeness of fuel combustion in the combustion chamber. The obtained data on changes in CO₂ concentration can be useful in selecting the most suitable mode of engine operation, and the presented approaches to combustion processes organization can be used by developers in designing combustion chambers of natural gas-fired gas turbine engines.

The article proposes a new thermal scheme of a regenerative gas turbine unit. By means of it a technical contradiction is supposed to be solved: on the one hand, to retain compactness of a gas turbine unit typical for the currently existing simple scheme and, on the other hand, its efficiency increase as with the regenerative cycle. Theoretical prerequisites of a possibility of creating a regenerative gas turbine unit with increasing of the recovery factor at the same size of a waste heat exchanger in order to increase the efficiency factor are presented. As a result, the supply of secondary air (cooling the flame tube and combustion products in the combustion chamber) for heating into the waste heat exchanger is eliminated in the new scheme. Conservation of the primary air consumption (for fuel oxidation) with the unchanged waste heat exchanger area results in an increase in the exhaust heat recovery factor and consequently an increase in the efficiency factor relative to the simple cycle. The resulting small size of the waste heat exchanger noticeably reduces the hydraulic losses at the unit outlet compared to the classical regenerative scheme. As a consequence, a significant drop in capacity is avoided. An increase in the primary air temperature, improved mixing and combustion conditions of the fuel mixture, combined with a reduction in hydraulic losses, may lead to an increase in the efficiency factor of the new scheme to the values characteristic of the classical regenerative scheme. However, the latter statement requires experimental verification. Low metal consumption of the waste heat exchanger in the new scheme, preservation of excess air ratio (secondary air temperature remains at the same level as in the simple scheme), and therefore the former sizes of compressor and turbine, will allow, in the author’s opinion, technically and economically simplifying modernization of existing gas turbine units (used, for example, in gas compressor units, marine and aircraft turboshaft engines) operating according to the simple scheme.

In 2020, a new coronavirus pandemic was one of the challenges for the Gazprom Group and the rest of the world. The main task during this period was to protect our own employees, as well as to help people living in the regions where the Gazprom Group is present. Employees are seen as one of the main strategic resources that ensure competitiveness and contribute to the Gazprom Group’s success in achieving its goals. In the challenging epidemic environment, it was important to organize effective management of Gazprom transgaz Moscow LLC aimed at ensuring reliable and stable natural gas supplies to infrastructure facilities in 14 Russian regions, and to adjust the Company’s business processes in order to meet obligations for uninterrupted gas transmission. In order to maintain the health of the Gazprom transgaz Moscow employees and the continuity of the production processes, special measures packages were developed and tested to prevent the spread of coronavirus infection. The article presents the Company’s experience in overcoming pandemic waves and prognostic assessment of employee morbidity with new strains based on the developed mathematical model. It shows how the application of the predictive method has allowed the Company’s business processes to be adapted to the new conditions. In particular, a system of stage-by-stage planning of measures to prevent the spread of coronavirus infection, prevent and minimize its consequences, which complies with legislative, corporate requirements and recommendations for organizing work in the conditions of a coronavirus pandemic, based on proven practices and response algorithms, was proposed to normalize the activities of Gazprom transgaz Moscow.

The article discusses improving the effectiveness of sustainability risk management in vertically integrated companies. The regulatory and methodological documents in the risk management and sustainable development areas are analyzed, as well as the best practices used in large international companies (including oil and gas). Suggestions are made on the expediency of revising the existing sustainable development model in favor of the Russian Federation and the members of the Eurasian Economic Union. Recommendations are given to improve the efficiency of corporate governance in vertically integrated companies (including oil and gas) by integrating the existing risk management methodology with the emerging approaches to sustainable development management. Company managers can use these recommendations to build an effective risk management system for sustainable development.

Diagnosing pipeline insulation state is an urgent problem in the main gas pipeline operation. The insulation is prone to delamination and loss of its protective properties as a result of soil corrosion in soil electrolytes, which can penetrate under the film under certain conditions. For various reasons, the existing methods for corrosion defect detection in pipes do not allow for high reliability and accuracy in locating delaminations and discontinuities without technically difficult and costly direct assessment. At the same time, the soil corrosion causing hydrogen emission due to cathodic depolarization can be an enabling factor for resolving the problem upon creating a specialized highly technological system for recording hydrogen flow above the gas pipeline route. Since the intensity of the hydrogen flow released by cathodic depolarization is proportional to the dissolution rate of the metal under the film, an underfilm corrosion monitoring system was developed. Its sensors can accumulate the upward hydrogen flow on an electrochemical membrane and record the element’s concentration. The hydrogen content distribution above the soil surface in the gas pipeline axis area allows for the reliable location of developing underfilm corrosion spots. The study aimed to evaluate the effectiveness of the proposed monitoring system by locating the underfilm corrosion spots on a main gas pipeline by the recorded hydrogen concentration level above the soil surface. The results were controlled by subsequent direct assessment. A hydrogen concentration exceeding the background level in a considered pipeline section was the criterion to record an underfilm corrosion spot. A series of field tests for the monitoring system at various sections of gas pipelines confirmed its effectiveness and practical applicability. The direct assessment revealed apparent underfilm corrosion spots in pipeline sections with hydrogen concentrations exceeding the background values.

The article uses the example of constructing underwater crossings through natural and artificial obstacles via automated pipeline shield penetration under different conditions and by different organizations to consider the following indicators of the rate of penetration: – mechanical rate reflecting the average sinking speed of the bottom hole; – technical rate reflecting the penetration progress rate, which covers the entire range of the process operations needed; – commercial rate reflecting the ratio of meters drilled to the calendar time of the tunneling operations; – cycle rate reflecting the use of the tunneling equipment. These figures and the average rate of penetration in each soil group were determined for all the main pipeline crossings considered. The highest average rates of penetration were found in sandy and gravel soils and the lowest – in clay and rocky soils. The study identified the causes for the declining rate of penetration of pipeline crossings through natural and artificial obstacles, which lie in difficult construction conditions with inadequate technology, equipment, and materials and low quality of the equipment and materials. Analyzing rates of penetration of pipeline crossings allows to plan the implementation of investment projects; select the most qualified contractors; allocate the unproductive time during construction; determine the compliance of the equipment, rock cutting tool, driving modes with the geological conditions, determine the number of crews and the amount of auxiliary staff and equipment required for the planned scope of work.

The article presents the experience of analysis of the factors effecting gas imbalance and the results of operational automatic calculation of the gas inventory in the crude gas transmission system through the pipelines of Gazprom dobycha Orenburg LLC at the Orenburg oil, gas, and condensate field. The analysis shows that a significant contribution to the value of the actual imbalance is made by the gas inventory in gas pipelines and the phase changes during gas transportation. Consideration of the phase changes requires the development of the mathematical models of the gas transportation process and specialized software. The results of measurements of the condensate falling out of gas during gas transportation and degassing gas volumes required for model development and adjustment are not available due to the lack of appropriate technological measurement units. At the same time, gas inventory in the gas gathering pipelines can be calculated on the basis of pressure values in the individual sections of the pipeline by means of the telemetry systems. Consideration of this factor makes it possible to considerably reduce the number of unscheduled inspections and to respond promptly to the observed deviations from the regime. The approach to gathering and processing of information coming from metering systems for monitoring of dynamics of changes in gas inventory in the gas pipelines is presented, the realization of software which automates the calculation of gas inventory on the basis of data of telemechanics system is discussed.