Natural Gas Generation Research Articles

Analysis of different methods of suppressing generator noise reaching indoor noise

The noise which occurs during the operation of the auxiliary power units is a disturbing factor, although its level varies depending on the environment. This high level of noise in occupational areas can cause not only health but also accidents risks. While silencers are mostly preferred for active noise control, acoustic foam or textile products are preferred according to passive control methods. In this review, the noises produced by the generators were examined and the studies in the literature on suppressing these noises were evaluated by making comparative analyzes. New recommendations have been developed according to the results of the comparative analysis. In case the sampled natural gas generator is closed with 2 mm thick plywood and a steel framed box covered with an acoustic sponge, the sound pressure level is approximately 30 dB in low frequency diesel + electric generators using a silencer according to active control methods. In measurements; It was observed that it decreased from 93.2 to 88.4 dB. While materials such as an acoustic sponge, which are preferred in passive control methods, are open-celled and porous structures, it is advantageous to have sound absorption capacity, but it can be a disadvantage due to its synthetic content.

Hydrocarbon generation and expulsion process in the deepwater area of the Qiongdongnan Basin of China: insights from artificial thermal maturation experiments

A series of natural gas fields have been discovered in the deepwater area of the Qiongdongnan Basin (QDNB) of China. However, the natural gas generation process and mechanism still exist controversy. Hence, two semi-open systematic pyrolysis experiments were conducted on a modified apparatus to study the natural gas generation process and mechanism in the deepwater area of the QDNB in this study, including pressured experiments and non-pressure experiments. In the pressured experiments, a stress pressure ranges from 37.6 to 188.2 MPa and fluid pressure ranges from 14.4 to 96.0 MPa based on the thermal evolution model of the QDNB. In non-pressured experiments, only fluid pressure from 2.0 to 5.0 MPa for a hydrous condition was compared with pressured experiments. The experiment results indicate that the pressured experiments could decrease the generated yields, expulsion efficiencies and expulsion process of the liquid hydrocarbons. Moreover, the suppression effect appears to be stronger under high evolution than that of low-maturity stage. Additionally, liptinite preservation exists during the liquid hydrocarbons and natural gas generation at temperature over 420 °C, whereas the liquid hydrocarbon is cracking to gas at temperature over 500 °C as a function of lithostatic stress, fluid pressure, temperature and time. Hence, pressure plays an important role in influencing expulsion efficiencies and expulsion process of the liquid hydrocarbons and natural gas generation in the high maturity stage.

Geochemical characteristics and origin of crude oil from Carboniferous volcanic rocks in the Hongche Fault Zone of the Junggar Basin of China

In recent years, significant advances have been made in the exploration of Carboniferous volcanic reservoirs in the Hongche Fault Zone of the Junggar Basin of China, showing good prospects for further exploration. However, the large variation in the physical properties of crude oil and the complex distribution rule inhibit the one-step exploration. In this study, the PM scale of the biodegradation of crude oil and source of crude oil were studied using experimental methods that target the properties, bulk properties and biomarker compounds of crude oil. The exploration potential of crude oil in this area was analysed, and an accumulation model of crude oil was established. Based on the differences in biomarker compounds and the degree of biodegradation, crude oils were divided into four groups and seven subgroups. Additionally, the analysis of the biomarker compounds of crude oil combined with the hydrocarbon-generation history of source rocks showed that there were at least two periods of oil charging in this area. The first period was the late Triassic, with crude oil derived from the P1f source rock. Owing to the strong tectonic activity during the late Indosinian movement, the oil reservoirs were distributed in the footwall of the fault zone, and the oil in the reservoir exhibited different degrees of biodegradation, forming crude oils of subgroup I1, II and III1. The second period was Cretaceous, during which the P1f source rock was in the natural gas generation stage, and the P2w source rock was at a mature stage. A small part of the crude oil formed by the P2w source rock migrated to the Carboniferous reservoirs and mixed with the crude oil formed by the earlier P1f source rock, resulting in crude oils of subgroups I2, III2, and IV2. The crude oil in the studied area originated from the source rocks in the sag during the peak of oil generation. As tectonic activity approached stability in the latter period, it is speculated that there may be well-preserved primary oil and gas reservoirs in the footwall and slope areas of the fault, making these potential exploration sites.

Assessing flexibility for integrating renewable energies into carbon neutral multi-regional systems: The case of the Chilean power system

Reducing emissions from power systems requires enhancing the penetration of non-conventional renewable energy sources (NCRE) in the generation mix. However, such penetration requires high levels of operational flexibility in order to ensure an adequate balance between generation and demand. Concentrating solar power plants with thermal storage (CSP-TES) and battery energy storage systems (BESS) have shown to possess technical characteristics compatible with such high flexibility requirements. However, due to the high capital costs of these technologies, decision-makers must seek for cost-effective configurations and operation modes. This study presents the development of a methodological framework for designing the long-term transition of a multi-regional energy system towards a low carbon emission system. The sought system is characterized by a high penetration of NCRE, and the use of CSP-TES, BESS and electricity transmission settings for providing effective levels of operational flexibility. For this, the transformation of the Chilean electricity system between the years 2018–2050 is studied, using a tailored modification of the well-known OSeMOSYS optimization tool for energy systems planning. The main results indicate that by 2050, and considering a baseline scenario defined for 2016, for most of the scenarios studied the renewable electricity generation would be at least a 90 % and CO2 emissions would be 75 % lower. Furthermore, it is shown that providing operational flexibility to the system requires a mixed generation from hydroelectric reservoirs, CSP-TES plants, BESS, pumped-storage hydropower and natural gas generators. The obtained results allow planning the capacity and operation of CSP and BESS plants, which are adapted to the future flexibility requirements of the Chilean electric power system. Incentive policies like stimuli to growth BESS, would favor primarily the photovoltaic growth of the system at the expense of CSP-TES capacity, while CSP-TES growth incentives would maintain photovoltaic generation levels, but would decrease Wind and natural gas generation.

Generation and geochemical signatures of natural gas from solid bitumen: Implications from closed and stepwise semi-open pyrolysis experiments

Solid bitumen has been acknowledged as an important source of overmature shale gas. However, the gas generation potential, chemical signatures and carbon isotopic compositions of natural gas derived from solid bitumen in an overmature hydrocarbon system are not well-understood with respect to various geological conditions. In this study, a relatively low-maturity solid bitumen from Cambrian reservoirs in the northwest Sichuan Basin was pyrolyzed in both closed and stepwise, semi-open systems. In the closed system, methane generated in the overmature thermal stage is dominated by the secondary cracking of wet gas and cumulative methane carbon isotopic values that are 4.4‰–14.8‰ lighter than the carbon isotope composition of the original solid bitumen. In semi-open systems, the gas is predominantly generated from residual solid bitumen and has wetness (i.e., C2–C5/C1–C5 by volume) values of generally less than 1%. At the same thermal maturity levels, the carbon isotope composition of methane in various semi-open systems is 4.4‰–10.0‰ heavier than those in the closed system and may also be isotopically heavier than the carbon isotope value of the original solid bitumen. The present study also illustrates that the calculated gas yields and methane carbon isotopes within a certain thermal maturity range in the closed system cannot be compared with those from residual solid bitumen as measured in the corresponding semi-open systems. This highlights the need to conduct specific semi-open pyrolysis experiments to investigate the late gas generation potential and geochemical signatures of natural gas from solid bitumen when the geological system is not a closed system. By comparing the above-mentioned results with the geochemical characteristics of Wufeng-Longmaxi shale gas from the Changning and Jiaoshiba gas fields of the Sichuan Basin, southwest China, it is suggested that the shale gas examined in this study is most likely generated in semi-open systems rather than in a closed system. In other words, the early-generated gas has been expelled from the shales, leaving the late-generated gas from residual solid bitumen and/or kerogen as the main gas source in the present hydrocarbon system.

The role of natural gas in reaching net-zero emissions in the electric sector

Replacing coal with natural gas has contributed to recent emissions reductions in the electric sector, but there are questions about the near- and long-term roles for gas under deep decarbonization. In this study, we assess the potential role for natural gas and carbon removal in deeply decarbonized electricity systems in the U.S. and evaluate the robustness of these insights to key technology and policy assumptions. We find that natural-gas-fired generation can lower the cost of electric sector decarbonization, a result that is robust to a range of sensitivities, when carbon removal is allowed under policy. Accelerating decarbonization to reach net-zero in 2035 entails greater contributions from natural gas than in 2050. Nonetheless, wind and solar have higher generation shares than natural gas for most regions and scenarios (52-66% variable renewables for net-zero scenarios versus 0-19% for gas), suggesting that natural gas generation can be substituted more easily than its capacity.

Environmental justice and power plant emissions in the Regional Greenhouse Gas Initiative states.

Policies to reduce greenhouse gases associated with electricity generation have been a major focus of public policy in the United States, but their implications for achieving environmental justice among historically overburdened communities inappropriately remains a marginal issue. In this study we address research gaps in historical and current ambient air emissions burdens in environmental justice communities from power plants participating in the Regional Greenhouse Gases Initiative (RGGI), the country's first market-based power sector emissions reduction program. We find that in RGGI states the percentage of people of color that live within 0-6.2 miles from power plants is up to 23.5 percent higher than the percent of the white population that lives within those same distance bands, and the percentage of people living in poverty that live within 0-5 miles from power plants is up to 15.3 percent higher than the percent of the population not living in poverty within those same distance bands. More importantly, the transition from coal to natural gas underway before RGGI formally started resulted in large increases in both the number of electric-generating units burning natural gas and total net generation from natural gas in environmental justice communities hosting electric-generating units, compared to other communities. Our findings indicate that power sector carbon mitigation policies' focusing on aggregate emissions reductions have largely benefitted non-environmental justice communities and have not redressed the fundamental problem of disparities in pollutant burdens between EJ and non-EJ communities. These must be directly addressed in climate change and carbon emissions mitigation policy.

Incorporation of water-derived hydrogen into methane during artificial maturation of source rock under hydrothermal conditions

To investigate the origin of CH bonds in thermogenic methane (CH4), a solvent-extracted sample of organic-rich Eagle Ford shale was reacted with heavy water (D2O) under hydrothermal conditions (350 bar) in a flexible Au-TiO2 cell hydrothermal apparatus at a water-to-rock ratio of approximately 5:1. Temperature was increased from 200 to 350 °C over the course of one month and the concentrations of aqueous species and methane isotopologues were quantified as a function of time. In general, production of hydrogen, CO2, alkanes, and alkenes increased with time and temperature. Methane formed during the early stages of the experiment at 200 °C was primarily C1H4 with some CH3D. With progressively higher temperatures, increasing proportions of deuterated isotopologues were produced. Near the end of the experiment, the concentration of CD4 exceeded that of all other isotopologues combined. These results suggest that competition between rates of kerogen-water isotopic exchange and natural gas generation may govern the D/H ratio of thermogenic gases. Furthermore, hydrogenation of kerogen by water may be responsible for hydrocarbon yields in excess of those predicted by conventional models of source rock maturation in which hydrocarbon generation is limited by the amount of organically bonded hydrogen.

Policy spillovers, technological lock-in, and efficiency gains from regional pollution taxes in the U.S.

We used the US-TIMES energy-system model in conjunction with integrated assessment models for air pollution (AP3, EASIUR, InMAP) to estimate the consequences of local air pollutant (LAP) and carbon dioxide (CO2) policy on technology-choice, energy-system costs, emissions, and pollution damages in the United States. We report substantial policy spillover: Both LAP and CO2 taxes cause similar levels of decarbonization. Under LAP taxes, decarbonization was a result of an increase in natural gas generation and a near-complete phaseout of coal generation in the electric sector. Under a CO2 tax, the majority of simulated decarbonization was a result of increased electric generation from wind and solar. We also found that the timing of the CO2 and LAP taxes was important. When we simulated a LAP tax beginning in 2015 and waited until 2025 to introduce a CO2 tax, the electric sector was locked into higher levels of natural gas generation and cumulative 2010–2035 energy system CO2 emissions were 8.8 billion tons higher than when the taxes were implemented simultaneously. A scenario taxing CO2 and LAPs simultaneously beginning in 2015 produced the highest net benefits, as opposed to scenarios that target either CO2 or LAPs, or scenarios that delayed either LAP or CO2 taxes until 2025. Lastly, we found that net benefits compared to business as usual are higher under a regional versus a national LAP-tax regime, but that efficiency gains under the regional tax are not substantially higher than those under the national LAP-tax policy.

Depositional Environment and Organic Matter Enrichment of Early Cambrian Niutitang Black Shales in the Upper Yangtze Region, China

Natural gas generation is the result of organic matter degradation under the effects of biodegradation and thermal degradation. Early Cambrian black shales in the Upper Yangtze Region are rich in organic matter and have shown great shale gas potentiality in recent years. Nevertheless, the enrichment mechanism and distribution of organic matter in these black shales between different sedimentary settings, such as intra-platform basin, slope, and deep basin, are still poorly understood. In this paper, based mainly on elemental geochemistry, a comprehensive study of the marine redox conditions, primary productivity, sedimentation rate, terrigenous input, hydrothermal activity, and water mass restrictions was conducted on the Early Cambrian Niutitang black shale in the Upper Yangtze Region. Our data showed that an intra-platform basin received a higher terrigenous input and that it deposited under more restricted conditions than the slope and deep basin settings. The primary productivity in the slope and deep basin settings was higher than that in the intra-platform basin setting. In the intra-platform basin, the productivity increased from its inner part to its margin. For the slope and deep basin settings, the high paleoproductivity generated large amounts of organic matter and its preservation was synergistically affected by the redox conditions. In contrast to the slope and deep basin, the preservation of organic matter in the inner part of the intra-platform basin was mainly controlled by redox conditions because the paleoproductivity in it was much lower than in the slope and deep basin settings. The intra-platform basin margin was the most favorable area for accumulating organic matter.

Economic and emission analysis of running emergency generators in the presence of demand response programs

Industrial plants in Iran, similar to many other developing countries, use diesel or natural gas generators mainly as backup power during a grid outage. Depending on the electricity network configuration, these emergency generators might be able to deliver electricity to the grid and thereby contribute to demand response (DR) programs. Hence, Iran's Ministry of Energy (MOE) has policies and incentives to promote the use of emergency generators during peak hours. This paper investigates the economic and carbon dioxide emission implications of such DR policies by the MOE. Results show that the current policy promotes diesel generators that are economically beneficial to the companies but are more carbon intensive than the natural gas generators. To mitigate the climate change with a minimum impact on the economic interest of the companies, the future DR policies can be amended. The revised incentive structure proposed by this study is simple but effective and ensures that the lower carbon emitting natural gas generators would become more economically attractive than diesel generators. Following the proposed approach to set the incentives, the natural gas generators would be more beneficial according to the MOE policy in 2019 if the difference between the diesel incentive and natural gas incentive was less than 711 Rial.

Nonlinear seismic inversion by physics-informed Caianiello convolutional neural networks for overpressure prediction of source rocks in the offshore Xihu depression, East China

Pressure prediction has long been one of subject of research focuses in petroleum geology and exploration, but is traditionally limited to moderately overpressured formations due to disequilibrium compaction based on the empirical velocity-pressure model. Overpressures in the Xihu depression are caused by fluid expansion due to the generation of natural gas in source rocks. The resulting abnormally pressured gas reservoirs manifest as a high-pressure structure with the thick mud-coated thin sand (MCS) that remains largely unaddressed in prediction. Such gas-producing overpressures make traditional prediction methods unapplicable because of the significant influence of high gas contents on seismic velocities. We employ a frequency-dependent quality factor Q–pressure petrophysical model because of the sensitivity of acoustic attenuation to overpressures. However, acoustic attenuations from rock physics and sonic logging present an uncertain dependence on pore pressures. This implies that overpressure prediction is a typical physical system that is characterized by both deterministic mechanism and statistical behavior, which resorts to physics-informed deep learning methods. We take the Q–pressure petrophysical model as the activation function of Caianiello convolutional neurons with an attempt to combine deterministic and statistical mechanisms for overpressure prediction. Such convolutional neurons render strong feature extraction and powerful learning ability and are used to construct physics-informed Caianiello convolutional neural networks (CCNNs) for overpressure prediction in the Xihu depression. The comprehensive CCNNs-based seismic inversion scheme for overpressures consists of reservoir petrophysical modeling, deep learning for neural wavelets, well-seismic correlation analysis, deconvolution-based inversion for an initial pressure model, and input-signal reconstruction to improve the initial pressure model. With drill stem tests (DSTs), well logs, and 3D seismic data, we conduct the overpressure prediction associated with cross validation in the Xihu depression, which demonstrates the applicability of the physics-informed CCNNs inversion scheme. Predicting reliability away from the training wells usually depends on the geological complexity of areas under study. Nevertheless, the information representation in the trained CCNNs can be improved gradually by feeding new well data during the development of an oil field.

Quantifying the electricity, CO2 emissions, and economic tradeoffs of precooling strategies for a single-family home in Southern California*

Abstract High fractions of variable renewable electricity generation have challenged grid management within the balancing authority overseen by the California’s Independent System Operator (CAISO). In the early evening, solar resources tend to diminish as the system approaches peak demand, putting pressure on fast-responding, emissions-intensive natural gas generators. While residential precooling, a strategy intended to shift the timing of air-conditioning usage from peak-demand periods to cheaper off-peak periods, has been touted in the literature as being effective for reducing peak electricity usage and costs, we explore its impact on CO2 emissions in regional grids like CAISO that have large disparities in their daytime versus nighttime emissions intensities. Here we use EnergyPlus to simulate precooling in a typical U.S. single-family home in California climate zone 9 to quantify the impact of precooling on peak electricity usage, CO2 emissions, and residential utility costs. We find that replacing a constant-setpoint cooling schedule with a precooling schedule can reduce peak period electricity consumption by 57% and residential electricity costs by nearly 13%, while also reducing CO2 emissions by 3.5%. These results suggest the traditional benefits of precooling can be achieved with an additional benefit of reducing CO2 emissions in grids with high daytime renewable energy penetrations.

Carbon-hydrogen isotopic systematics of gases generated in semi-closed hydrous pyrolysis of type I source rock with the presence of formation water: Implications for gas isotope partitioning under supercritical conditions

Hydrocarbon gas is a significant type of clean energy, and understanding its carbon-hydrogen (C–H) isotopic behaviour during hydrocarbon generation is essential for determining the gas genesis. Hydrous pyrolysis is an artificial method to simulate natural gas generation process with the presence of water. Formation water is a type of ubiquitous saline water in oilfields, whereas not commonly utilized in hydrous pyrolysis. To determine the influence of formation water on C–H isotopic systematics of hydrocarbon gas (methane, ethane and propane), two series of semi-closed hydrous pyrolysis experiments were conducted in 275–550 °C for the type I Green River Shale source rock using distilled water and formation water. Hydrocarbon gases generated in two series of experiments have similar δ13C ratios yet slightly different δD ratios at individual temperatures, which is likely attributed to the water-organic interaction as formation water has a different δD ratio compared to distilled water. The δ13C and δD ratios of gas increase with the rising of thermal maturity level, and exhibit quadratic correlations with vitrinite reflectance (VR) values in both series of experiments. The presence of supercritical water in hydrous pyrolysis does not significantly affect the gas C–H isotopic partitioning behaviour because gases collected below and above the critical temperature (374.2 °C) display consistent δ13C (δD)-VR patterns. Partial C–H isotopic reversals (δ13C2>δ13C3, δD2>δD3 or δD1>δD2) are observed during the pre-oil to oil generation peak and gas generation stages, which are likely mainly affected by gas mixing as evidenced by rigorous correlations between δ13Cn (δDn) ratios and reciprocals of the gas proportion (1/Cn).

Increasing atmospheric helium due to fossil fuel exploitation

Fossil fuels contain small amounts of helium, which are co-released into the atmosphere together with carbon dioxide. However, a clear build-up of helium in the atmosphere has not previously been detected. Using a high-precision mass spectrometry technique to determine the atmospheric ratio of helium-4 to nitrogen, we show that helium-4 concentrations have increased significantly over the past five decades. Obtaining a direct measure of the rise in atmospheric helium-4 is possible because changes in nitrogen are negligible. Using 46 air samples acquired between 1974 and 2020, we find that the helium-4 concentration increased at an average rate of 39 ± 3 billion mol per year (2σ). Given that previous observations have shown that the ratio between helium-3 and helium-4 in the atmosphere has remained constant, our results also imply that the concentration of helium-3 is increasing. The inferred rise in atmospheric helium-3 greatly exceeds estimates of anthropogenic emissions from natural gas, nuclear weapons and nuclear power generation, suggesting potential problems with previous isotope measurements or an incorrect assessment of known sources. Mass spectrometry measurements show that the concentration of helium in the atmosphere has risen over the past five decades due to fossil fuel emissions.

Deep-basin gas generation via organic–inorganic interactions: New insights from redox-controlled hydrothermal experiments at elevated temperature

Under hot, deep-basin conditions, hydrogen-to-carbon ratios of residual kerogen are low. Whether ubiquitous water in sedimentary environments contributes hydrogen directly to hydrocarbon gas formation through organic-inorganic interactions is, therefore, critical for natural gas generation. Accordingly, we conducted laboratory experiments on immature to overmature kerogens at 300–600°C and 700 bar to examine the chemical interactions between kerogens and fluid under varying redox states and hydrothermal conditions. Mineral buffers, comprised of magnetite-hematite, nickel‑nickel oxide, cobalt‑cobalt oxide, and molybdenum‑molybdenum trioxide, were added to the experiments to control the redox state of the fluid from geologically reasonable to generally excessive values. The kerogens and mineral buffers were spatially isolated using double-capsule techniques to prevent contact catalysis.Our results indicated that chemical interactions between kerogens and water depended strongly on the kerogen thermal maturity and fluid redox state. The chemical interactions of overmature kerogens with reducing water were stronger than those of immature kerogens, which could be ascribed to the weaker competitive transfer of hydrogen from organics to organics than from water to organics. Unexpectedly high amounts of hydrocarbon gas were generated by incorporating water-derived hydrogen in the pyrolysis of overmature kerogens, and the yields increased under low to high reducing fluid conditions for a given temperature. Along with the increasing thermal maturity, residual kerogen eventually became ineffective for hydrocarbon gas generation through reduction reactions. Demethylation, bridge bond cleavage reaction, aromatic structure ring opening reactions in residual kerogen and subsequent redox reaction of intermediate products with reducing fluids is evidenced as the possible reaction mechanisms. The produced hydrocarbon gas under fH2 level of oilfield water is characterized by high dryness (99 mol%) and more-enriched 13C in CH4 compared with precursors. Natural gas deep within the Sichuan and Appalachian basins with similar characteristics suggests that our simulated organic–inorganic interactions could occur widely under natural conditions. Consequently, a potentially prolific source of natural gas may be formed by the overmature source rocks in the deep basin and fluid redox should be considered for gas potential evaluation of overmature source rocks.

Well-to-wheel nitrogen oxide emissions from internal combustion engine vehicles and alternative fuel vehicles reflect real driving emissions and various fuel production pathways in South Korea

South Korea is suffering from high concentrations of particulate matters in the air caused by domestic and foreign influences, and the government is attempting to reduce nitrogen oxide (NOx) emissions in the transportation sector, which could be causing secondary generation of these emissions. This paper presents a life cycle assessment (LCA) on the six base fuels and finally produced results for WTW NOx emissions for internal combustion engine vehicles (ICEVs) (gasoline), ICEVs (diesel), battery electric vehicles (BEVs) and fuel-cell electric vehicles (FCEVs) through LCA based on electric power generation sources and hydrogen production methods. For the tailpipe emissions of ICEVs, the real driving emission (RDE) NOx emission data from previous studies supported by the Ministry of Environment in South Korea were considered, in addition to the NOx emissions based on the New European Driving Cycle (NEDC) test procedure. As a result, the WTW NOx emissions of ICEVs (gasoline), ICEVs (diesel-euro6), and ICEVs (diesel-euro6d-temp) were calculated at 0.113, 0.776 and 0.154 g/km, respectively, when considering the RDE NOx emissions. In addition, for BEVs, coal, natural gas and power generation mixes were calculated at 0.113, 0.059, 0.065 g/km, respectively, depending on the power generation source. In the case of FCEVs, naphtha cracking (NC), steam methane reforming (SMR with natural gas), SMR (with landfill gas), electrolysis, and production mixes were calculated as 0.088, 0.080, 0.030, 0.254, 0.088 g/km, respectively, according to the hydrogen production method. It was noted that the WTW NOx emissions from the most recent diesel-fueled ICEVs (euro6d-temp) was similar to those of FCEVs and ICEVs (gasoline), although pre-euro6d-temp diesel vehicles suffer from significantly high WTW NOx emissions, mostly from tailpipe emissions under real driving conditions. In this study, it is possible to analyze the life cycle from the actual operational data in a uniform perspective for all vehicle types. In addition, it is able to derive WTW results for alternative fuel vehicles according to various power generation sources and hydrogen production methods and to understand the effect of upstream energy sectors.

Pore Structures of the Lower Permian Taiyuan Shale and Limestone in the Ordos Basin and the Significance to Unconventional Natural Gas Generation and Storage

In the Ordos Basin, multiple sets of coal seams, organic-rich shale, and limestone are well developed in the Permian Taiyuan Formation, which are favorable targets for collaborative exploration of various types of unconventional natural gas resources, including coalbed methane, shale gas, and tight gas. In this study, core samples from the Permian Taiyuan Formation in the eastern margin of the Ordos Basin were used to carry out a series of testing and analysis, such as the organic matter characteristics, the mineral composition, and the pore development characteristics. In the shale of the Taiyuan Formation, the total organic carbon (TOC) content is relatively high, with an average of 5.38%. A thin layer of black shale is developed on the top of the Taiyuan Formation, which is relatively high in TOC content, with an average of 9.72%. The limestone in the Taiyuan Formation is also relatively high in organic matter abundance, with an average of 1.36%, reaching the lower limit of effective source rocks (>1%), being good source rocks. In the shale of the Taiyuan Formation, various types of pores are well developed, with relatively high overall pore volume and pore-specific surface area, averaging 0.028 ml/g and 13.28 m2/g, respectively. The pore types are mainly mineral intergranular pores and clay mineral interlayer fractures, while organic matter-hosted pores are poorly developed. The limestone of the Taiyuan Formation is relatively tight, with lower pore volume and pore-specific surface area than those of shale, averaging 0.0106 ml/g and 2.72 m2/g, respectively. There are mainly two types of pores, namely, organic matter-hosted pores and carbonate mineral dissolution pores, with a high surface pore rate. The organic matter in the limestone belongs to the oil-generation kerogen. During thermal evolution, the organic matter has gone through the oil-generation window, generating a large number of liquid hydrocarbons, which were cracked into a large number of gaseous hydrocarbons at the higher mature stage. As a result, a large number of organic matter-hosted pores were generated. The study results show that in the Ordos Basin, the shale and limestone of the Permian Taiyuan Formation have great potential in terms of unconventional natural gas resources, providing a good geological basis for the collaborative development of coal-bearing shale gas and tight limestone gas in the Taiyuan Formation.

Factor Analysis Of Energy Security: Net Import Dependency

This paper analyzes various aspects of energy dependency and identifies the hidden factors behind national energy security. Based on a review of the scientific literature, the factors that reduce energy security in the consumption of natural gas, oil, and nuclear energy generation were identified. One such factor is import dependency on energy resources. Import dependency on energy is a crucial characteristic of energy security and can exacerbate the effects of external aggression, non-competitive behavior, and pressure. Given the energy crisis of 2022, most countries around the world have revised their energy security policies to reduce import dependency by diversifying supplies and reducing dependence on Russian energy resources. The factor analysis of energy dependency ratios, 1990-2020, was used to study the energy security of the EU27 countries. The factor analysis was performed for annual indices calculated using the Eurostat database of “Simplified energy balances.” The paper hypothesized the existence of latent relationships between energy security variables for the twenty-seven EU countries. The hypothesis was verified using Bartlett’s sphericity test and Kaiser-Meyer-Olkin criterion. The results of hypothesis testing showed its statistical significance (the p-value < 0.05) and the possibility of factor analysis. Correspondence indices also indicated the adequacy of possible prediction of a set of variables. The factor analysis was executed in Python using the FactorAnalyzer module (the release 0.4.0). The principal factor extraction and the varimax rotation model were used to obtain the initial solution, preserving the orthogonality of the loading matrix. The factor structure of the model was confirmed for four factors consisting of the twenty-eight elements. The received four factors model allowed us to describe around 80% of the cumulative variance. It was found that each factor separately explained 46.89%, 15.80%, 10.91%, and 6.39% of the variance, respectively.

Tafonomia de Invertebrados Fósseis do Devoniano no estado do Paraná: Contribuições aos Estudos sobre Potencial de Hidrocarbonetos Vinculados ao Projeto Folhelho (LAGESED-UFRJ)

The shales are a recent frontier of studies in Sedimentary Geology, stimulated by the new exploratory panorama of Shale Gas, despite being the sealant of many petroleum systems. However, Brazil has not kept up with this evolution. The generation of natural gas associated with paleontological studies is unprecedented and fundamental for determining the real regional potentialities in a process of advancing scientific and technological knowledge in this field of studies in Brazil. Taphonomic studies of fossil macrofauna and ichnology are integrated with sedimentological data, expanding the capacity for paleoenvironmental interpretation of the sedimentary facies. Samples from three different outcrops in the vicinity of Arapoti, Ventania, and Piraí do Sul in the state of Paraná were analyzed. Thus, during the analyses of the fossil material, two tafofacies and three ichnofacies were identified: Skolithos, archetypal and distal Cruziana. The paleontological analyses proposed here provided support for the biostratigraphic correlations, paleoenvironmental and paleoecological interpretations of the outcrops prospected, helping to evaluate the quality of the shales of the Ponta Grossa Formation from the point of view of hydrocarbon generation.