Natural Gas Extraction Research Articles

Dynamic Analysis on Carbon Metabolism of the Northern Region of China Under the Background of Carbon Emission Trading Policy

The launch of the national carbon emissions trading market in China is a policy to carry out the Beautiful China initiative and to establish a low-carbon economic development system that promotes carbon emission and waste reduction. In order to detect the carbon metabolic processes of the pilot and nonpilot municipalities or provinces in the northern region of China， the theory of urban carbon metabolism and the methods of input-output analysis and ecological network analysis were introduced and used. The results showed that the direct carbon emissions of Beijing and Tianjin had decreased， but their embodied carbon emissions had increased since 2012. The direct and embodied carbon emissions of the pilot sectors in Beijing and Tianjin had the same trend； specifically， the emissions of the sectors of mining and washing of coal， extraction of petroleum and natural gas， and manufacture of non-metallic mineral products decreased significantly， but the sectors of production and supply of electric power and steam with high carbon emission increased. The same trend of the embodied carbon emission intensities of sectors with that of their embodied carbon emissions verified that the embodied added values were not growing with the promotion of the carbon emission trading market. Subsequently， the embodied carbon emission of the pilot sectors in all the municipalities and provinces of the northern region were all contributed mainly by the emissions embodied by a path length less than 6； therefore， it showed that more attention should be paid to the trade among sectors with a path length less than 6 and reducing their carbon emissions. Furthermore， from 2007 to 2012， products or service trading among sectors mostly concentrated on sectors within one municipality or province， and these products or services had the characteristics of low carbon emission. Since 2012， the integration development of the Beijing-Tianjin-Hebei urban agglomeration and the new regional economic patterns established in the northern region both promoted the trading across provinces and across sectors. This research is based on the background of the carbon emission trading policy and aims to build a methodology to identify the key actors and paths in a metabolic system. This could provide a scientific basis for regional policy implementation and regional long-term sustainable development.

Effects of environmental information disclosure on the green development of mining industry: Evidence from Chinese provincial mining sub-sectors

How environmental information disclosure (EID) affects green transformation of mining industry (MI) is still unknown. Based on the panel data of China's provincial mining sub-sectors, this study explores the effects of EID on the green total factor productivity (GTFP) of China's mining sub-sectors and its influence mechanism. The research shows that EID exerts an inverted U-shaped influence on the GTFP growth of MI, implying that reasonable EID facilitates the green transformation of China's MI, while excessively EID requirements may be counterproductive. The above conclusion still holds after considering the endogeneity and conducting a series of robustness tests. Further analysis shows that the impact of EID on the GTFP of MI has a lag and long-term, and the current EID affects its future GTFP. Meanwhile, EID has a more remarkable effect on the GTFP of the MI in the eastern and central regions and the mining and washing of coal (S3) and extraction of petroleum and natural gas (S4). Mechanism analysis reveals that EID affects the GTFP of the MI through technological innovation, but due to the ‘black expected effect’, EID is still unable to increase the GTFP of the MI through energy structure. This study provides important insights for the government to fully leverage the positive role of social supervision in promoting the green development of heavy polluting industries such as MI.

Investigation of a fuel-free power generating plant and evaluation of the effectiveness of its use

The development of resource-saving technologies for existing energy sources is one of the priority tasks of the energy strategy of the Republic of Uzbekistan, which provides for the reduction of losses and cost reduction at all stages of the technological process during the extraction, preparation and transportation of natural gas. Today, it is very promising to utilize the energy of excess pressure of natural gas at gas distribution stations using expander units. A solution to the problem of lack of gas heating in the expander-generator unit can be a heated installation scheme through the use of a gas heating system with an air heat pump unit. Calculations of the energy efficiency of an expander generating unit were carried out under various operating conditions when heating natural gas in front of the expander using a heat pump unit.

Scarcity and instability: Transforming societies through equitable distribution mechanisms

Under the framework of SDG 16, namely Peace, Justice and Strong Institutions, one key underexplored area of inclusion relates to the means of ensuring access to justice through the equitable governance of scarce resources, and mechanisms to promote equal and structural access to opportunities across society. This research sets out to answer the following questions across three case studies: (1) What is the relationship between critical or scarce resources and political conflict in the region under study?; (2) On what basis is the scarce or critical resource currently distributed within the region under study?; (3) What formal or informal governance mechanisms are in place to manage access to critical or scarce resources, and resolve conflicts created by it?; and (4) What improvements could be made to ensure more inclusive and equitable access to the distribution of this resource? The three proposed case studies, namely, Central Mali (land), Northeastern Kenya (water), and northern Mozambique (extraction and revenues of natural gas), have unique political and geographic features that are indivisible from peace and security. In each case, a blend of formal and informal mechanisms is used, but these often involve competing mandates, are guided by socioeconomic dynamics or are unenforced, potentially leading to different types of localised conflict. This paper argues that, in order to prevent conflict around the governance of natural resources, communities need to be involved in a blend of informal and formal governance mechanisms from the outset. While the exact nature of these governance mechanisms may differ according to the nature of the natural resource and its extraction, there is a need to move from top-down towards people-centred approaches. Moreover, there should be efforts to develop specific SDG 16 targets related to environmental governance.

Horizontal borehole azimuth optimization for enhanced stability and coal seam gas production

Horizontal boreholes have been widely used to extract natural gas from coal seams. However, these boreholes can encounter severe instability issues leading to production interruption. Optimizing drilling azimuth is a potential solution for enhancing borehole stability while considering gas production. In this work, we improved and implemented a dual-porosity, fully coupled geomechanical-hydraulic numerical model into COMSOL Multiphysics to investigate into this factor. The sophisticated numerical model incorporates various critical factors, including desorption-induced matrix shrinkage, stress-dependent anisotropic fracture permeability, and the interactions of gas flow and reservoir deformation in matrices and fractures.A suite of simulation scenarios (e.g., varying coal strength) was carried out to quantify the impact of drilling azimuth on coal permeability evolution, cumulative gas production, and the borehole break-out width for Goonyella Middle Seam of Bowen Basin, Australia. The model was calibrated against both theoretical permeability values and field gas production data. Due to the lack of directly measured matrix permeability data, the actual gas production was used to back calculate the best-matched matrix permeability, which is 0.65 μD for this particular work. Moreover, based on the breakout shape and induced volumetric strains around the borehole, drilling along the maximum horizontal stress does not necessarily lead to the best stability of the borehole, as generally believed. A drilling azimuth between 0° and 60° results in similar breakout width, whereas a drilling azimuth between 60° and 90° achieves the most efficient gas production. By considering both gas production efficiency and borehole stability, for this particular reservoir condition, the optimum drilling azimuth is determined to be between 45° and 60°.This study presents a practical approach for determining the optimum drilling azimuth in coal seam gas extraction through in seam boreholes.

Seismic Beacon-A New Instrument for Detection of Changes in Rock Massif.

The seismic beacon is a new instrument that allows for the measurement of changes in a rock massif with high sensitivity. It is based on effects, which affect the propagation of harmonic seismic waves generated continuously with stable and precise frequency and amplitude. These seismic waves are registered by a system of seismic stations. The amplitude of the seismic signal is very small, and it is normally hidden in a seismic noise. Special techniques are applied to increase the signal-to-noise ratio. In 2020, the first prototype of the seismic beacon was constructed in a laboratory, and field tests were performed in 2022 and 2023. During the tests, the changes in spectral amplitude and phase of seismic waves were detected, which is interpreted as the changes in material properties. These measurements testified the basic functionality of the device. The seismic beacon has been developed primarily for the detection of critical stress before an earthquake, which is manifested by non-linear effects such as higher harmonics generation. In addition, it could be used, for example, in the detection of magma movements, groundwater level changes, changes in hydrocarbon saturation in rocks during the extraction of oil and natural gas, or the penetration of gases and liquids into the earth's crust.

Impact of unrecovered shale gas reserve on methane emissions from abandoned shale gas wells

Shale gas, with its abundance and lower carbon footprint compared to other fossil fuels, is an important bridge fuel in the ongoing energy transition. However, a notable concern in shale gas exploration is fugitive methane emissions during the extraction, development, and transport of natural gas. While most existing works evaluate methane emissions released by well fracking, completion and operation, the greenhouse footprint of unproductive shale gas wells (often abandoned or orphaned) has received little scrutiny. A large fraction of these emissions from abandoned shale gas wells are due to the diffusive transport of methane trapped in nanoporous shale matrix, which is poorly understood. Here, we develop a theoretical kinetic approach to predict methane diffusive flux from heterogeneous shale matrix. Our theoretical model is based on a layer sequence formulation and accurately considers multiple flow mechanisms, including viscous flow, gas slippage, and Knudsen diffusion and their mutual interactions. The model is validated against the observed methane diffusion data obtained from high-pressure and high-temperature experimental measurements on Marcellus shale. We find that methane diffusive flux increases as reservoir pressure decreases. We estimate methane emission due to diffusive transport up to 20 × 103 m3 per well per day, which is comparable to emissions from flowback fluid. For the first time, unrecovered natural gas in the shale matrix is demonstrated to be the main source of methane emissions from abandoned shale gas wells. Given the long-lasting nature of diffusive transport to shale gas seepage, it is suggested that regulatory requirements should be implemented to provide long-term monitoring of methane emissions from abandoned shale gas wells.

Liquefied Natural Gas Value Chain: A Comprehensive Review and Analysis

AbstractOver the past few decades, the liquefied natural gas (LNG) business has experienced astounding expansion and gained global relevance. LNG has emerged as a key element in meeting the world's rising energy demand while working to cut carbon emissions, since it is a cleaner and more adaptable energy source. The entire process from natural gas extraction to consumption is covered in the presented analysis of the LNG value chain, starting out by looking at the discovery and production of natural gas reserves, highlighting important innovations and methods used during the extraction stage. The procedures used to treat and purify natural gas in order to meet the strict standards for liquefaction are detailed. Analysis of the liquefaction process reveals numerous liquefaction technologies, e.g. the well‐known conventional liquefaction and the cutting‐edge floating LNG and small‐scale LNG facilities. LNG storage and transportation, as critical components in the value chain, are examined in great detail. When the LNG reaches its destination, regasification plays a crucial role in repurposing it as a gas for distribution and consumption. Regasification technologies, such as conventional onshore terminals, floating storage and regasification units, and land‐based regasification facilities, are covered. Concerns regarding methane emissions and the carbon footprint, the potential for reducing greenhouse gas emissions through new technology, the environmental impact of LNG, and the economics of LNG are also considered across its value chain.

Study on the influence of non-newtonian fluid characteristics on the hydraulic performance and internal flow field of multiphase pump

As a pivotal prospective clean energy source, the secure and efficient extraction of natural gas hydrate has emerged as a forefront concern within the global oil drilling industry in recent years. In this study, a self-developed multiphase pump adapted to "gas-liquid-solid" three-phase mixing is used to extract natural gas hydrate slurries which have non-Newtonian characteristics. Prior research on pumps has primarily focused on water, introducing a significant disparity in handling slurries containing hydrates. This paper investigates the hydraulic performance and flow field variations of a multiphase pump using three different concentrations of Herschel-Bulkley non-Newtonian fluids that exhibit rheological properties similar to natural gas hydrate slurries. Additionally, a viscous Newtonian fluid with seawater as the liquid phase medium is studied for comparison. The results show that the shear-thinning properties of the non-Newtonian fluid improve the efficiency of the pump. However, excessive concentration negatively affects the hydraulic properties. The flow field characteristics such as apparent viscosity and turbulent kinetic energy are closely related to the pump structure and fluid properties. Compared with viscous Newtonian fluid, the non-Newtonian fluid's also have a greater effect on the distribution of gas-solid phases.

Numerical simulation of heat transfer performance of spiral wound heat exchanger under sloshing condition

LNG floating production storage and offloading (FPSO) unit is a new type of floating production unit developed for offshore natural gas fields. It performs the functions of natural gas extraction, pretreatment, liquefaction, and storage. In this study, the heat transfer characteristics of a spiral-wound heat exchanger were studied using numerical simulations, which provides a basis for equipment selection and structural optimization of spiral-wound heat exchangers. The main research contents and conclusions are as follows. Under land-based simulation conditions, the heat transfer coefficient of the shell side of the spiral-wound heat exchanger decreases with an increase in the winding angle of the heat exchange tube, decreases with an increase in the spacing of the heat exchange tube, and increases with an increase in the outer diameter of the heat exchange tube. When the winding angle increased from 5° to 8°, the heat transfer coefficient decreased by 6.70%. The heat transfer coefficient of the shell side decreased by 13.21% when the heat exchange tube spacing increased from 14 to 17 mm. The heat transfer coefficient of the shell side increased by 22.89% when the outer diameter of the heat exchange tube increased from 9 to 12 mm. When the sloshing angle is constant, the heat transfer coefficient of the spiral-wound heat exchanger decreases with an increase in the winding angle and spacing of the heat exchange tubes, and increases with an increase in the outer diameter of the heat exchange tubes. When the structural parameters of the heat exchanger are constant, the heat transfer coefficient decreases as the sloshing angle increases. When the sloshing angle was less than 3°, the sloshing promoted heat transfer on the shell side. When the sloshing angle was higher than 7°, the heat transfer effect of the shell side deteriorated considerably, which weakened the heat transfer performance of the heat exchanger. When the sloshing period is constant, the heat transfer coefficient of the wound heat exchanger decreases with an increase in the winding angle and spacing of the heat exchange tubes, and increases with an increase in the outer diameter of the heat exchange tubes. When the structural parameters of the heat exchanger are constant, the heat transfer coefficient increases with sloshing period. When the sloshing period was greater than 15 s, the influence of sloshing on the heat transfer on the shell side of the heat exchanger was relatively weak.

Influence of Natural Gas Pipeline Right-of-Ways on Eastern Red-Backed Salamander Occurrence in the Northern Appalachians

Abstract Road and pipeline infrastructure development for natural gas extraction often results in forest fragmentation, which could negatively influence habitat quality for many amphibian species. We investigated occurrence dynamics of the eastern red-backed salamander Plethodon cinereus in relation to natural gas pipeline rights-of-way (ROWs) and forest structure characteristics in northern Pennsylvania, USA. We sampled 80 sites across two study areas by using coverboards, with each site containing sampling plots at the center of the ROW, the edge of the ROW, and 10 m and 30 m into the adjacent forest. We assessed the influence of ROW age, ROW width, distance from ROW, and five forest structure characteristics on plot occupancy probability. Eastern red-backed salamander occupancy probability decreased with ROW age and increased with distance from ROW. Our results indicate that eastern red-backed salamanders are negatively influenced by forest fragmentation for natural gas ROWs. Moreover, responses were time dependent, with occupancy probability declining with ROW age. Due to low detections, we were unable to analyze data for the other amphibians and reptiles encountered during the study. Our capture data indicate that ROWs could improve habitat quality for some snake species, but additional research is needed to better understand the influence of ROWs on reptile species. To reduce future forest fragmentation and impacts on eastern red-backed salamander populations, managers could consider placing pipelines along existing linear clearings and enhancing the habitat quality of ROWs for salamanders.

Study on improving liquid carrying performance of annular jet pump gas well with static mixer

AbstractIn the process of natural gas extraction, the phenomenon of liquid loading will affect the efficiency of gas well extraction and reduce the life of the well. Compared with conventional drainage gas extraction technology, the jet pump can not only reduce the bottom back pressure and ensure the stable production of gas reservoirs but also promote the final recovery rate. Since the jet pump relies on the interaction between fluid particles to transfer energy, the energy loss is large and the efficiency is low. To maximize the advantages of the gas‐driven jet pump, this study innovatively combines a static mixer with an annular jet pump. Utilizing the cyclonic effect produced by the static mixer, the original gas‐liquid axial motion is transformed into a stronger vortex motion, and the liquid droplets are changed into a liquid film that is easier to carry, which significantly improves the discharge efficiency of the jet pump. This study uses a combination of numerical simulation and experimental analysis to compare the associated effects of the new annular jet pump (NAJP) and the conventional annular jet pump (CAJP) on the liquid‐carrying performance of gas wells in terms of cyclonic effect, droplet breakage ratio, and pump efficiency. The results show that, compared with CAJP, NAJP increases the mass flow rate of the sucked fluid. The droplet breakage ratio increases by 15.4% year‐on‐year, while the critical liquid‐carrying flow rate is reduced by about 10.7%, resulting in a maximum pumping efficiency of 37%, an increase of about 30.7% year‐on‐year. At the same time, the reduction of the energy coefficient means lower energy consumption. In summary, NAJP is better than CAJP in terms of liquid‐carrying effect and efficiency.

A roadmap for sustaining marine minerals as the green economy transitions to the blue economy

This study looks at the impact of green economy activities on marine mineral conservation, emphasizing the critical significance of circular processes in building a sustainable blue economy. The research assesses the long-term viability of European blue economies using six indicators, including the value provided by the extraction of petroleum and natural gas and support activities for mining and quarrying projects. Municipal trash generation per capita and the amount of biowaste in recycling are used to determine circular effectiveness. According to the findings, a robust green economy performance is critical for increasing the sustainability of Europe's blue economy between 2012 and 2019. The link between the green and blue economies is nonlinear, with positive benefits shown when the green economy exceeds a particular threshold. Furthermore, the study validates these findings by investigating the impact of the green economy on ocean energy and marine minerals. These empirical findings have important significances for European authorities and policymakers aiming to effectively implement green programs in order to advance toward a sustainable blue economy and preserve marine mineral levels.

Natural gas extraction activities and host communities concerns in Sub-Saharan Africa: A reflection on the historical riots in Mtwara, Tanzania

This paper examines host community concerns associated with natural gas extraction in Tanzania. Host communities in the Mtwara region in Tanzania have resisted natural gas extraction activities in their area. Using this region as a case study, the research draws on in-depth interviews, focus group discussions, direct field observation, documentary films, and relevant documents to understand the community concerns raised. Through content analysis, five significant themes were identified. Communities report that historical riots were prompted by empty promises, irrational expectations and alienation of communities from participating in and benefiting from natural gas extraction activities. Also, communication hiccups and poor aftermath responses worsened the already fragile situation. Clear communication between host communities and the government that allows participatory dialogue with stakeholders is fundamental for addressing host community concerns before havoc erupts. Likewise, where regulations were not followed adequately, follow-up should be done to resolve emanating circumstances and to hold responsible people accountable for their actions.

Simulations of winter ozone in the Upper Green River basin, Wyoming, using WRF-Chem

Abstract. In the Upper Green River basin (UGRB) of Wyoming and the Uintah Basin of Utah, strong wintertime ozone (O3) formation episodes leading to O3 mixing ratios occasionally exceeding 70 parts per billion (ppb) have been observed over the last 2 decades. Wintertime O3 events in the UGRB were first observed in 2005 and since then have continued to be observed intermittently when meteorological conditions are favorable, despite significant efforts to reduce emissions from oil and natural gas extraction and production. While O3 formation has been successfully simulated using observed volatile organic compound (VOC) and nitrogen oxide (NOx) mixing ratios, successful simulation of these wintertime episodes using emission inventories in a 3-D photochemical model has remained elusive. An accurate 3-D photochemical model driven by an emission inventory is critical to understanding the spatial extent of high-O3 events and which emission sources have the most impact on O3 formation. In the winter of 2016/17 (December 2016–March 2017) several high-O3 events were observed with 1 h mixing ratios exceeding 70 ppb. This study uses the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) to simulate one of the high-O3 events observed in the UGRB during March 2017. The WRF-Chem simulations were carried out using the 2014 edition of the Environmental Protection Agency National Emissions Inventory (EPA NEI2014v2), which, unlike previous versions, includes estimates of emissions from non-point oil and gas production sources. Simulations were carried out with two different chemical mechanisms: the Model for Ozone and Related Chemical Tracers (MOZART) and the Regional Atmospheric Chemistry Mechanism (RACM), and the results were compared with data from seven weather and air quality monitoring stations in the UGRB operated by the Wyoming Department of Environmental Quality (WYDEQ). The simulated meteorology compared favorably to observations with regard to temperature inversions, surface temperature, and wind speeds. Notably, because of snow cover present in the basin, the photolysis surface albedo had to be modified to predict O3 in excess of 70 ppb, although the models were relatively insensitive to the exact photolysis albedo if it was over 0.65. O3 precursors, i.e., NOx and VOCs, are predicted similarly in simulations with both chemical mechanisms, but simulated VOC mixing ratios are a factor of 6 or more lower than the observations, while NOx is also underpredicted but to a lesser degree. Sensitivity simulations revealed that increasing NOx and VOC emissions to match observations produced slightly more O3 compared to baseline simulations, but an additional sensitivity simulation with doubled NOx emissions resulted in a considerable increase in O3 formation. These results suggest that O3 formation in the basin is most sensitive to NOx emissions.

Bulk and interfacial properties of methane-heavy hydrocarbon mixtures

Methane-heavy hydrocarbons are typical mixtures in natural gas extraction, purification and production processes. However, the microscopic behavior of methane diffusion, dissolution and adsorption within heavy hydrocarbon liquids has not been solved yet. Therefore, the bulk and interfacial characteristics of methane-heavy hydrocarbon mixtures were systematically analyzed. And the real and rippled interfaces were identified using a new method. The results indicate that density of heavy hydrocarbon-rich phase decreases with decreasing chain length and increasing pressure, while that of the methane-rich phase increases instead. When methane molecules dissolve into bulk liquids, heavy hydrocarbon chains stretch and the intermolecular separation distances increase. Additionally, the interaction energy between the two molecules is the main reason for system swelling. The Gibbs relative adsorption of methane improves until reaching the saturation limit as pressure adds. The intrinsic interface analyses show that the strong adsorption of methane mainly exists in the first surface layer in dilute solutions, which becomes more pronounced with increasing methane fraction. For heavy hydrocarbons with shorter chains, surface layers are narrower and their separation distances are reduced. Furthermore, methane molecules prefer staying at the outer edge of surface layers and are nearer to gas phase than heavy hydrocarbons by approximately 0.2–0.7 Å.

Measurement of gas-liquid flows with the combination of thermal sensors and conductance sensor

Gas-liquid two-phase flow is a typical phenomenon in energy and industrial production. Thus, flow measurement of gas-liquid flow is vital in the exploration and extraction of oil and natural gas. The thermal sensors are based on convection heat transfer between heating elements and fluid. These sensors have been widely used in flow measurement because of their high precision, and low-pressure loss, and it is not affected by fluid conductivity and viscosity. This study utilized the thermal conductivity difference in liquid and gas to design a measurement system that combines thermal sensors and a conductance sensor. Among them, the thermal sensors contain 2 upstream and downstream thermal resistors and a total of 28 thermocouples distributed over 7 sections (4 for each section) to capture axial and sectional thermal information. A rotating electric field conductance sensor (REFCS) serves to accurately determine gas holdups. The model tests show that the separated flow models have better accuracy than the liquid-phase acceleration models and pressure drop models. Inspired by the classical separated flow models, an improved heat transfer model based on flow patterns is developed by adding an additional superficial velocity term. Based on the mechanism that the heat transfer is dominated by the liquid phase, the superficial velocities are measured in combination with the drift-flux model. Overall, the average absolute percentage deviations (AAPD) for both the heat transfer coefficients and superficial velocities are less than 5%, indicating that the improved model has excellent performance and robustness for flow prediction in 20 mm pipes.

Study on Interaction Characteristics of Injected Natural Gas and Crude Oil in a High Saturation Pressure and Low-Permeability Reservoir

Natural gas injection is considered for enhanced oil recovery (EOR) in a high saturation pressure reservoir in block B111 of the Dagang oilfield, China. To investigate the interaction characteristics of injected natural gas and crude oil, the ability for dissolution–diffusion and miscibility–extraction of natural gas in crude oil was tested using a piece of high-temperature and high-pressure PVT equipment. The physical properties and minimum miscible pressure (MMP) of the natural gas–crude oil system and their interaction during dynamic displacement were analyzed using the reservoir numerical simulation method. The results show the following: (1) Under static gas–oil contact conditions, natural gas has a significant dissolution–diffusion and miscibility–extraction effect on the crude oil in block B111, especially near the gas–oil interface. The content of condensate oil in gas phase is 10.14–18.53 wt%, while the content of dissolved gas in oil phase reaches 26.17–57.73 wt%; (2) Under the reservoir’s conditions, the saturated solubility of natural gas injected in crude oil is relatively small. The effect of swelling and viscosity reduction on crude oil is limited. As the pressure increases with more natural gas dissolved in crude oil, the phase state of crude oil can change from liquid to gas; accordingly, the density and viscosity of crude oil will be greatly reduced, presenting the characteristics of condensate gas; (3) The MMP of natural gas and crude oil is estimated to be larger than 40 MPa. It mainly forms a forward-contact evaporative gas drive in block B111. The miscible state depends on the maintenance level of formation pressure. The injected natural gas has a significant extraction effect on the medium and light components of crude oil. The content of C2–C15 in the gas phase at the gas drive front, as well as the content of CH4 and C16+ in the residual oil at the gas drive trailing edge, will increase markedly. Accordingly, the residual oil density and viscosity will also increase. These results have certain guiding significance for understanding gas flooding mechanisms and designing gas injection in block B111.

CLASSIFICATION OF ECONOMIC SECTORS ACCORDING TO THE DEGREE OF THEIR TECHNOGENIC DANGER

The study develops an approach to the classification of economy sectors according to the degree of their potential technogenic danger to the population. The article provides a brief analysis of the history of the RF legislation in the field of industrial safety, and a review of current regulatory legal documents. The existing classifications of hazardous facilities were analyzed based on domestic and foreign studies. Industries and types of economic activity were classified according to the degree of their potential danger. The sectors with the highest hazard class include coal mining; production of coke and oil products; chemical products; rubber and plastic products; metallurgical production; provision of electricity, gas and steam; air conditioning. The sectors with the middle class of danger are the extraction of oil and natural gas, metal ores; production of foodstuff, drinks, tobacco products; production of paper; production of medicines and materials used for medical purposes; production of other non-metallic mineral products; sub-sectors of mechanical engineering, water supply and sanitation, transport, scientific research, etc. The proposed approach was tested in Moscow and it became clear that there are 635 enterprises operating in the city that have a type of economic activity classified as medium or high hazard class, they employ about 241 thousand people (as in 2020), and most of them (more than 90%) work at enterprises belonging to medium-hazardous industries. According to mobile operators’ data it was find out that up to a quarter of the Moscow population is daily concentrated in the areas of potential technogenic danger, which is significantly higher than indicated in official documents. Increased actual concentration of population in places of greatest danger is a serious problem from the point of view of ensuring the safety of citizens, and organizing rescue and evacuation measures in case of emergencies.

Effects of pipeline and well‐pad reclamation on topsoil properties: A meta‐analysis

AbstractThe development of horizontal drilling and hydraulic fracking has led to an increase in oil and natural gas extraction. Development of infrastructure to extract and transport these resources is expected to increase over the next few decades, resulting in extensive land disturbance. Although reclamation aims to sufficiently return disturbed lands to their pre‐disturbance use in an ecological sense, reclaimed rights‐of‐ways (ROW) commonly produce reduced crop yields. The objective of this study was to use meta‐analysis to determine soil disturbance trends across studies found in the peer‐reviewed literature. Papers that reported soil property data on disturbed ROWs and adjacent undisturbed sites were retrieved by searching the Web of Science database. Papers were separated by climate regions, resulting in analyses being conducted for studies in semiarid and humid climate regions. Results indicate that soil bulk density, soil organic matter, and pH are significantly increased on reclaimed ROWs. Soil metrics not incorporated in meta‐analysis due to insufficient observations or the possible presence of publication biases like a desire to publish significant results and poor study design (cation exchange capacity, calcium, phosphorus, magnesium, total nitrogen, electrical conductivity, sodium, sodium adsorption ratio, and texture) are assessed and discussed. Best management practices gleaned from studies incorporated into meta‐analysis are discussed to provide strategies to limit soil property disturbances.