Механико-химические и геодинамические проблемы, возникающие при эксплуатации подземных хранилищ газа со смесью водорода и метана

The objective of this article is the analysys of methods for preventing and eliminating hydrates formations, classifying them and choosing the best ones for use in underground gas storage facilities. Comprehensive measures for the stable operation of gas storage facilities in the presence of conditions for the occurrence of hydrates formations were developed. Zones, being potentially prone to the hydrates formation during the gas storage facilities operation were identified. The operational parameters of gas storage wells during gas withdrawal are analyzed. The identified wells were operated under difficult conditions due to the deposition of hydrates on the wellheads, in flowlines and process equipment of gas storage facilities. The places of the highest hydrates accumulation on underground gas storages were determined: from the bottomhole of wells to the gas purification unit of the gas gathering station. Hydrate-prone zones were identified by computational fluid dynamic (CFD) modeling at the location of regulating choke installations in underground gas storage facilities. The zones of the greatest hydrates accumulation on underground gas storages were determined: from the bottomhole of wells to the gas purification unit of the gas gathering station. The analysis of the methods used in gas storage facilities of Ukraine to prevent and eliminate hydrates formation was out. A set of measures was proposed to prevent the hydrates formation in storage facilities to ensure their stable operation. Based on the Euler approach (Mixture model) by CFD modeling, zones prone to hydrates formation were determined at the installation site of regulating chokes in underground gas storages. The influence of the degree of fittings opening on the location of potential zones prone to hydrates formation was estimated. The gas-dynamic processes in the internal cavity of the gas pipeline at the installation site of the control fittings were studied and their influence on the distribution of bulk particles of the gaseous and liquid phases was established. Based on the studies performed, it was recommended to change periodically the mode of well operation for a certain time by opening or closing the regulating choke under favorable conditions for the formation of hydrates, especially at low ambient temperatures. The obtained results of experimental studies and calculations showed that in order to solve the problem of hydrates formation at gas storage facilities, it is advisable to use diverse measures through the introduction of modern intelligent systems for monitoring and controlling the technological process. Further refinement of the algorithm of the proposed monitoring and control system with its approbation in production was provided. The results of the experimental studies and CFD modeling carried out allowed providing a more reasonable approach to the application of various available methods and measures to prevent hydrates formation in underground gas storage facilities. This approach made it possible to develop new effective ways and measures to prevent such complication. Based on the conducted experimental studies and modeling, the major zones prone to hydrates formation in underground gas storages were determined. The developed measures will allow timely detection and prevention of hydrates formation at gas storage facilities are original.

In response to Governor Brown’s January 2016 state of emergency proclamation regarding the Aliso Canyon gas leak, SB 826 (Leno, 2016) requested that the California Council on Science and Technology (CCST) provide the State with up-to-date information on all currently operating underground natural gas storage fields in California. CCST was instructed to provide an independent technical assessment answering three key questions about: The risks California’s underground gas storage facilities pose to health, safety, environment, and infrastructure; Whether California needs underground gas storage to provide for energy reliability through 2020; and How implementation of California’s climate policies changes the future need for underground gas storage. From a statewide field of leading energy researchers, CCST selected Jens T. Birkholzer, PhD, and Jane C.S. Long, PhD, to serve as co-chairs of the 12-member CCST Report Steering Committee – which supervised 21 Report Authors with expertise spanning hydrogeology and reservoir engineering, risk assessment, public and occupational health, greenhouse gas (GHG) emissions, and energy analysis and economics. Each report chapter was subject to a peer review process by independent experts, while another independent expert served as Report Monitor to oversee the process, ensuring that peer review comments were sufficiently addressed in the final report. An additional Oversight Committee reviewed the entire process, including conflict-of-interest declarations. The report’s findings and conclusions are based on a review of published literature and official and voluntary databases, which the Report Authors compiled between January through September 2017, and delivered to the California Public Utilities Commission in January 2018. Key findings and conclusions include: Safety: The risks associated with underground storage (UGS) facilities can be managed, and, with appropriate regulation and safety management, may become comparable to risks in other types of energy facilities found acceptable in California, such as oil refineries and natural gas power plants. At each UGS facility, the State should ensure timely and thorough implementation of the new regulations coming into force in 2018 set by the California Department of Conservation’s Division of Oil, Gas, and Geothermal Resources (DOGGR). Those regulations emphasize new and safer well completions, risk and safety management plans, and requirements for well integrity testing and monitoring. The report recommends that the State go further and require more quantitative risk assessment activities, including consideration of human and organizational factors affecting risk. The State should also implement an independent and mandatory review program to evaluate the effectiveness of these new regulations and the rigor of their application in practice, with opportunity for public comment and public dissemination of the review results. Facility-by-Facility Evaluation: Any industrial operation involves some risk to health, safety, and environment. This report assessed various risk-related characteristics across UGS facilities in California, and found a small list of facilities had relatively higher potential risk compared to others. Reliability of Natural Gas Supply: California’s energy system currently requires natural gas and UGS facilities to run reliably, primarily because many residential and commercial buildings in California rely on natural gas for heating during the winter, and because natural gas provides electricity when solar and wind power are not available. The peak demand for natural gas during the winter currently exceeds the ability of pipelines to bring natural gas into the State of California, so natural gas must be stored during periods of low demand in order to have it available to meet peak demand. Near-Term Alternatives to UGS: Closing any or all UGS facilities in the near term would involve replacing UGS facilities with new pipelines or natural gas storage capacity, and require very large investments. Such new natural-gas-related infrastructure would bring its own risks and would further obligate the State to the use of natural gas for decades. The risks, costs, and benefits associated with alternatives to UGS storage should be evaluated accordingly. Long-Term Need for Underground Gas Storage: California’s climate policies in future decades could still necessitate the continued use of natural gas. Also, energy systems that meet the climate goals may require underground storage of natural gas, biogas, or hydrogen, as well as sequestration of carbon dioxide. The State should develop a more complete and integrated plan to understand how the role of natural gas might evolve; assess possible energy portfolios that both meet GHG emission constraints and achieve energy reliability; and consider the potential need for UGS facilities in the future.

The EU Directives implementing the climate and energy package will result in the increased demand for natural gas in all EU countries, especially in Poland, whose energy management is coal-based. In the following decades we will observe the substantial increase in demand for natural gas as an energy carrier in power and heating sectors. Another factor, which will contribute to the increase in gas consumption, is the expansion of gas transmission and distribution network. In order to secure natural gas supply for the customers in is necessary to ensure the proper gas storage capacity, expand the existing underground gas storage facilities (UGS) and build new ones. Currently used Polish underground natural gas storage facilities allow storing 1.6 billion m3. Taking into consideration the expansion of investments in underground natural gas storage facilities and the projected increase in demand for natural gas, it is justified to build the new large salt cavern underground gas storage facility in Poland.

Gas injected or withdrawn from underground gas storage facilities may contain carbon dioxide or hydrogen sulfide, which are corrosive to steel objects. However, until recently, virtually no attention was paid to the danger of internal corrosion in underground gas storage facilities. There have been no targeted studies on the durability of such steel objects that would take into account the peculiarities of their operation. Due to the fact that an important aspect for obtaining reliable data is the correct choice of research methods, methodological approaches have been developed and applied to study the main aggressive factors by analyzing operational parameters in underground gas storage facilities. The main task was to test methods for studying the durability of material design and the composition of sediments formed as a result of exposure of steel equipment and pipelines to corrosive gas components. Further comparison of the obtained data with operational characteristics made it possible to determine the mechanisms of destruction of steel objects in underground gas storage facilities. The study and processing of basic operating conditions (temperature, pressure, hydrogen sulfide and carbon dioxide content), analysis of precipitations using scanning electron microscopy and X-ray diffraction, and metallographic studies of steel were carried out. The methodological approaches proposed by Gazprom VNIIGAZ LLC make it possible to objectively assess the dynamics of changes over time in temperature, pressure and content of hydrogen sulfide and carbon dioxide, followed by the determination of the partial pressures of these gases and a preliminary assessment of the potential corrosivity of environments in underground gas storage facilities. Analysis of pipe or equipment materials makes it possible to determine the degree of influence of microstructure features on the general or local course of corrosion. Studying the morphology of sediments allows us to trace the development of internal corrosion processes. A set of studies carried out by Gazprom VNIIGAZ LLC makes it possible to develop and select the necessary measures to reduce the risk of internal corrosion of steel gas pipelines and equipment of underground gas storage facilities.

The article analyzes the data on the creation of North Caucasus underground gas storage facilities (UGS) in1960-1971 and the injection and production of gas into storage facilities during exploration and industrial operation.The followings have been obtained as a result of the analysis. Increased gas injection and extraction from gas storagefacilities in the former USSR; change in the absolute value of gas over time, while it is pumping into storage, takingout and its rising; a decrease in the volume ratio of gas injection and extraction over time. Compression of water withgas is not very large. Therefore, it is hardened as follows. Under formation conditions, gas has a lower density thanwater, i.e. it is light and its viscosity is less than water, gas has a large mobility. In underground gas storages (UGS),gas is divided into active and buffer. The part of the gas that is extracted from the storage is called the active part(when the demand for gas decreases in the summer). Buffer gas refers to the part that is constantly in undergroundgas storage (UGS). It provides pressure in the reservoir and is sufficient to supply active gas to the production wells.The maximum and minimum pressures are obtained in underground gas storages (UGS-s) where the share of buffergas is very high. The volume of active and buffer gas in underground gas storages (UGS) depends on its geometricdimensions, shape, depth of deposition, porosity, rock permeability, minimum and maximum pressure in the annulus,gas injection and extraction technologies.

Summary The rational system of development gas fields and the operation of underground gas storage facilities are directly dependent on the amount of information received from each well, i. e. the degree of study productive formation. The most important sources of information about the gas layer and the wells of gas field are the gas-dynamic methods research of wells. The research results are processed by binary equation of gas flow to the well bottom. The coefficients of filtration resistance determined in the research process are used in the future to calculate the technological operating conditions of well and gas-dynamic calculations of options for development gas deposits or cyclic operation in UGS. Studies are conducted at four or six steady state modes. However, carrying out such complex of studies for operating gas fields and UGS with the number of wells 100–300 or more due to certain difficulties. First, they require a high cost of working time and a partial declin e in productivity of deposit or UGS; and secondly, the reliability of determination research parameters is often low due to incomplete stabilization of well operation mode. The article proposes an accelerated method of research for gas wells in steady-state regimes using the power formula of gas flow to the well bottom. The application of this method to gas deposits and underground gas storage facilities of Precarpathian has made it possible to significantly accelerate the research process in wells without substantial reducing the reliability of their results.

This paper addresses various legal issues associated with underground gas storage, including the potential for commercial underground gas storage, legislative developments in relation to underground gas storage, specific legal issues in relation to commercial underground gas storage, matters to address in a commercial underground gas storage agreement, and the potential application of third party access regimes to underground gas storage reservoirs and facilities.

The storage of natural gas in geological structures such as depleted fields, aquifers and salt caverns plays an important role in a gas supply system as it balances the fluctuation of gas demand and price. Hydraulic loss due to fluid flow through gas storage production equipment and an interfering effect from nonequal productivity index of storage wells may have an important influence on gas storage performance. An integrated mathematical model is developed based on underground gas storage facility production data. Using this model, the hydraulic loss is determined. A real test case that consists of a gas storage reservoir linked to the surface facility is analysed. The mathematical model uses an experimentally determined pressure drop coefficient in chokes. The base case scenario created using real gas storage facility data enables the achievement of a good history match with the given parameters of the gas storage reservoir. Using the history match simulation case as an initial scenario (a base case), two different scenarios are created to determine the injection and withdrawal performance of the gas storage field. The results indicate that the pressure drop in chokes, when fully open as a constraints in an underground gas storage facility, has a significant impact on gas storage operations and deliverability.

Underground gas storage as a promising natural methane bioreactor and reservoir?

The experience of applying microseismic infrasonic exploration method ANCHAR to the timelapse monitoring the outlines of pay zones of oil and gas reservoirs under production accounts for more than 10 years. Presented are results of microseismic monitoring for a number of targets – Kaluga underground gas storage facility, Orenburg oil-gas-condensate field and etc. In all these studies the position and displacement of the outlines of pay zones were reliably fixed by microseismic and verified by independent methods. The results demonstrate high prospects of applying the ANCHAR monitoring to post-exploration and operation of HC reservoirs and underground gas storage facilities.

Leroy natural-gas storage site is an anticlinal, fault-bounded, aquifer-storage system located in Wyoming, USA. Based on its abundant data, uncontrolled leakage history and subsequent control by the facility operators, a modeling framework was developed for studying reservoir behavior, examining pressure and gas-inventory histories, as well as gas and brine leakage, and evaluating the sensitivity of that behavior to uncertainty about reservoir properties. A three-dimensional model capturing the bounding fault, layered geologic stratigraphy, and surface topography was calibrated by history data of reservoir pressure and gas inventory. The calibrated model predicted gas arrival at the ground surface that was consistent with the timing of observed gas bubbling into a creek. A global sensitivity analysis was performed to examine the parameters influencing fault leakage, and a geomechanical stability analysis was conducted to investigate the likelihood of fault reactivation. In general, it is shown that a discrete leakage pathway is required to explain the observed gas leakage and its subsequent operational control by reducing reservoir pressures. Specifically, the results indicate that fault leakage is a plausible explanation for the observed gas leakage. The results are relevant to other natural-gas storage sites, as well as other subsurface storage applications of buoyant fluids, such as CO2.

The problems of the creation of the system for identification and well parameters monitoring based on the results of the well geophysical researches are considered in this article. One of the main sources of information in the described system are drilling wells. The information about them, taken from geophysical researches and observations, is used for the solution of very wide range of technological and environmental problems of the underground gas storage facilities (UGS) operation.

PurposeThe purpose of this study is to investigate the impact of the construction and operation of underground gas storage (UGS) facilities, under the prism of the recent rise in energy prices. The focus is on developing energy markets interconnected with gas producers through pipelines and has access to liquefied natural gas (LNG) facilities in parallel.Design/methodology/approachThrough a focal market in Europe, the authors estimate the economic value for both stakeholders and consumers by introducing a methodology, appropriately adjusted to the specificities of the domestic energy market. The Transmission System Operator, the Energy Market Regulator, the Energy Exchange and Eurostat are the main data sources for our calculations and conclusions.FindingsThe authors investigate the perspectives of UGS facilities, identifying financial challenges considering specific energy market conditions which are barriers to new storage facilities. Nevertheless, the energy price rocketing coupled with the security of gas supply issues, which arose in autumn 2021 and were continuing in 2022 due to the Russia–Ukraine crisis, highlight that gas storage remains, at least for the midterm, at the core of European priorities.Originality/valueThe paper emphasizes on developing markets toward green transition, proposing tangible policy recommendations regarding gas storage. A new methodological approach is proposed, appropriate to quantify the economic value of UGSs in such markets. Last, a mix of energy policy options is suggested which include regulatory reforms, support schemes and new energy infrastructures that could make the gas storage investments economically viable.

Underground hydrogen storage, compared to surface storage, offers a higher capacity, provides long-term storage, and requires fewer surface installations. Underground hydrogen storage site selection is affected by various factors, including availability of energy sources to produce hydrogen from fossil fuels and renewables, energy consumption in a specific area, accessibility to the existing infrastructure, and availability of underground storage media. These factors vary in different locations. Wyoming, as the second largest energy supplier in the U.S., has a significant share of the influencing factors. This study ranks Wyoming counties based on fossil fuels supply, renewables, energy consumption, and underground storage facilities as well as different type of media for storage such as depleted hydrocarbon reservoirs, abandoned coal mines, and potential trona caverns. Depending on the preferred factors, different counties can be prioritized for underground hydrogen storage site selection. This study is beneficial for storage site selection in Wyoming; however, individual sites should be further investigated for optimal site selection.

Nowadays, energy raw materials, especially environmentally friendly raw materials, are becoming increasingly important. These raw materials include natural gas called the "blue fuel". As it is known, natural gas is extracted from deposits located at often great depths by means of both vertical and horizontal drilling. It is important that both vertical and horizontal wells are characterised by high efficiency in terms of obtaining the highest possible productivity, which will allow to exploit the existing resources of the deposit in the shortest possible time. The paper analyses the influence of such factors as reservoir pressure, thickness of reservoir, length of a horizontal section, average permeability of a reservoir, turbulence coefficient and water exponent on the process of lifting a liquid phase during operation of a horizontal well. The calculations were carried out using data concerning exploitation of the "B" natural gas field. The calculations were carried out using the "IHS PERFORM" computer programme, which is the leading industry software for carrying out analyses of productivity changes in gas wells. The following correlations were used in the horizontal well performance analysis: - Joshi's correlation for calculating productivity for a horizontal well - Hagedorn & Brown correlation for determining the course of pressures in a well for two-phase flow, - Lee, Gonzalez & Eakin correlation for calculating changes in gas viscosity, and - Dranchuk & Purvis - Robinson correlation for calculation of deviation factor of real gas "z". The results of the calculations are presented in the form of graphs. In the final part of the article, conclusions are given, summarising the results of the analysis. In the further part of the article the author focused on the course of operation of a horizontal well located at an underground gas storage facility.