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Futures market is an important part of the financial market, with a high degree of liquidity and leverage effect. However, the futures market is also faced with various risk factors, such as price fluctuations, market shocks, supply and demand changes. In order to better determine the risk correlation between specific futures markets, this paper uses the wavelet transform-quantile Granger causality test method to identify the risk correlation of four major futures markets in the US futures market from the end of January 2009 to the end of March 2023, such as gold, crude oil, soybeans and natural gas. It provides a new perspective and method for the risk correlation identification of the futures market. The results show that futures contracts with different maturities and price fluctuations under different quantiles have a significant impact on risk correlation. Specifically, in 1-month and 6-month futures contracts, the strongest bidirectional risk correlation exists between gold and natural gas (T-statistics -15.94 and 10.92, respectively); In the 1-month futures contract, there is also a strong bidirectional risk association between crude oil and soybeans and natural gas (T-statistics are 6.87, 17.42, -2.05, 7.35, respectively), while in the 6-month futures contract, there is a bidirectional risk association between crude oil and soybeans (T-statistics are -2.49 and 18.374, respectively). However, natural gas has unidirectional risk association with crude oil and soybean (t statistics are 2.7 and -3.35, respectively); There is a bidirectional risk correlation between gold and soybean, that is, the risk correlation between gold and soybean increases with the increase of the degree of price fluctuation; There is a one-way risk association between gold and crude oil, soybean and gold, and crude oil and natural gas (the T-statistic is greater than the critical value of 1.96). In addition, there is a strong bidirectional or unidirectional risk association between all varieties at the 0.95 quantile. The research results of this paper have certain reference value for the supervision, investment and risk management of the futures market. This paper uses the wavelet transform and quantile Granger causality test method to identify the risk correlation of the futures market, providing a new perspective and method for the risk correlation identification of the futures market, and uses relatively new data to ensure the effectiveness of the empirical analysis. However, there are some limitations in this paper, such as the applicability of wavelet transform-quantile Granger causality test method. Future studies can further expand the sample range, compare the effects of different methods, and explore the risk transmission mechanism between different varieties., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Zi Qian Wu. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

As the logistics and plate capital of China, the sources and regional transport of O 3 in Linyi are different from those in other cities because of the significant differences in industrial structure and geographical location. Twenty-five ozone pollution episodes (OPEs, 52 days) were identified in 2021, with a daily maximum 8-h moving average O 3 concentration (O 3-MDA8 ) of 184.5 ± 22.5 μg/m 3 . Oxygenated volatile organic compounds (OVOCs) and aromatics were the dominant contributors to ozone formation potential (OFP), with contributions of approximately 23.5-52.7% and 20.0-40.8%, respectively, followed by alkenes, alkanes, and alkynes. Formaldehyde, an OVOC with high concentrations emitted from the plate industry and vehicles, contributed the most to OFP (22.7 ± 5.5%), although formaldehyde concentrations only accounted for 9.4 ± 2.7% of the total non-methane hydrocarbon (NMHC) concentrations. The source apportionment results indicated that the plate industry was the dominant O 3 contributor (27.0%), followed by other sources (21.6%), vehicle-related sources (18.0%), solvent use (16.9%), liquefied petroleum gas (LPG)/natural gas (NG) (8.8%), and combustion sources (7.7%). Therefore, there is an urgent need to control the plating industry in Linyi to mitigate O 3 pollution. The backward trajectory, potential source contribution function (PSCF), and concentration weighted trajectory (CWT) models were used to identify the air mass pathways and potential source areas of air pollutants during the OPEs. O 3 pollution was predominantly affected by air masses that originated from eastern and local regions, while trajectories from the south contained the highest O 3 concentrations (207.0 μg/m 3 ). The potential source area was from east and south Linyi during the OPEs. Therefore, it is critical to implement regional joint prevention and control measures to lower O 3 concentrations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Chongqing Fuling shale gas field, the largest shale gas exploration site in China, produces a large amount of oil-based drill cuttings (OBDC) every year, which is a hazardous waste. Traditional treatment methods such as solidification/stabilization did not recycle the valuable components such as petroleum hydrocarbons. Pyrolysis is proven to be an efficient method that can recover those components. This study firstly investigated the pyrolysis kinetics by two different methods on the basis of detailed material characterization, and then taking the workers and the surrounding ecological environment as the analysis object, the human health risk assessment (HHRA) and ecological risk assessment were evaluated respectively before and after pyrolysis. The results showed that the pyrolysis of OBDC was divided into three stages, and the cracking of light hydrocarbons stage was the key control step for pyrolysis process. The activation energy E increased gradually during the pyrolysis progress. The HHRA results showed that pyrolysis could greatly reduce the non-carcinogenic risk, carcinogenic risk and ecological risk by 59.6 %, 62.8 % and 75 % respectively. However, the carcinogenic risk after pyrolysis was still higher than the critical value 10 -6 ., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The Niger Delta region in South-South Nigeria, on Africa's West Coast, is densely populated. The region, which contains a substantial stock of crude oil and natural gas, has been nicknamed "the engine room" for Nigeria's economic development and progress. It is responsible for up to 90% of the country's economic growth (or gross domestic product/GDP). The region has multiple ecosystems, such as the aquatic environment, that are critical to the survival of the area's various habitats and living species. However, the same region has witnessed unjustifiable environmental pollution arising from oil activities over the years of exploration and production which has orchestrated negative consequences on the Niger Delta ecosystem. This has led to extended negative consequences on natural resources, which also have detrimental repercussions psychologically, ecologically, socially, economically, and physically which, in turn, impacts the overall health of the affected individuals. This write-up provides an overview of the major drivers of the oil leakage in Nigeria's Niger Delta ecosystem as well as the major impacts on the environment. It will also analyze numerous means of remediation in use and extend such for a more inclusive and productive option. Moreover, this review offers key measures that may help to maintain long-term policies for reducing adverse implications and increasing the living standard for the Niger Delta area's affected communities., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The emission factor (EF) is a parameter used to assess vehicle emissions. Many studies have reported EFs for vehicles in driving conditions. However, the idling emissions should not be neglected in characterizing actual vehicle emissions in congested large cities, where idling is very common on the road. Whereas, EF data for idling vehicles have scarcely been reported in the literature, let alone comparison of different fuels. In this study, the EFs of passenger cars burning four types of fuels - gasoline, compressed natural gas (CNG), diesel, and liquefied petroleum gas (LPG) were measured and compared. The emissions data for CO, CO 2 , unburned hydrocarbon (HC), and NO were recorded to calculate fuel-based EFs in units of g pollutants/kg fuel burned. EFs for CO, HC, and NO were compared for the four fuels. Diesel vehicles had the highest EF for CO, with an average value of 35.12 ± 21.37 g/kg fuel, due to low concentration of CO 2 in lean operation compared to CO emission. CNG vehicles had the highest EF for HC, with an average value of 28.15 ± 11.97 g/kg fuel, due to high concentration of unburned methane gas due to slow CNG flame speed whereas diesel vehicles again had the highest EF for NO due to high temperature and pressure and freezing of NO decomposition reaction, with an average value of 12.07 ± 5.37 g/kg fuel. Further comparison was conducted to analyze the effects of two additional variables on EF: engine displacement volume and model/brand year. Only the gasoline-fueled vehicles showed an increase in EFs (for CO, HC and NO) with the vehicle age according to the model year. However, no clear correlation was observed for CNG, LPG, and diesel-fueled vehicles. Finally, the EF results were compared with those reported in the literature, which have been measured in various countries under both idling and non-idling conditions. Because the idling EFs were not substantially smaller than those under moving conditions, and vehicles spend substantial time idling in large cities, idling emissions should not be ignored in the emission inventories for large cities., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

To mitigate climate change, reducing carbon dioxide (CO 2 ) emissions is of paramount importance. China, the largest global CO 2 emitter, proposes to peak carbon emissions by 2030 and become carbon neutral by 2060; transforming the energy structure represents one of the primary means of addressing carbon emissions; thus, it is essential to investigate the impacts of alternate energy sources throughout the country. Based on energy consumption and carbon emissions data from 30 provincial-level administrative regions in China (excluding Tibet, Hong Kong, Taiwan, and Macau, due to the lack of data), the study here investigated the shares of coal, petroleum, natural gas, and non-fossil energy sources (i.e., hydropower, nuclear power, wind power, solar power, and biomass power), as they relate to total, per capita, and per unit GDP CO 2 emissions via spatial regression. The results showed that: (1) The epicenters of coal and carbon emissions have shifted from the east to the central and western regions; (2) There is a significant correlation between energy structure and carbon emissions: coal has a positive effect, petroleum's effects are positive at first, and negative subsequently; while both natural gas and non-fossil energy sources have a negative impact; (3) Provincial-level carbon emissions are affected by energy structure, carbon emissions in neighboring regions, and other factors.

The Chinese government has called for clean and effective energy substitution for cooking in rural areas. This paper assesses the environmental and economic impacts of various types of cooking fuels and stoves. According to the assessment results, the environmental impacts are highly influenced by the types of fuels and the efficiency of stoves used for cooking. Using biogas, liquefied petroleum gas (LPG), and natural gas for cooking instead of solid fuels can significantly reduce environmental emissions. To provide 1 megajoule (MJ) of useful cooking heat, the environmental costs of lump coal, honeycomb briquettes, and straw are the largest, estimated to be 80.4 yuan/MJ, 73.1 yuan/MJ, and 71.4 yuan/MJ, respectively. In addition, the economic assessment results show that the most expensive source of cooking fuel is LPG, with an average annual cost of 1700 yuan, while the cost of straw and firewood is the cheapest, at less than 100 yuan. The average annual cost of electricity is higher than that of natural gas. Regarding the substitution effects, using natural gas for cooking is better than using electricity. The environmental benefit of electricity substitution is only 10%-20% of natural gas substitution, and the corresponding increasing cost for residents is 1.5 times that of natural gas substitution., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The construction sector is a critical part in achieving energy conservation targets in China, as it accounts for approximately 30% of the annual national energy supply for building construction. Therefore, this study integrates multi-regional input-output analysis and ecological network analysis to track energy fluxes and pathways from the construction sector, aiming to facilitate the configuration of the energy-flow structure and improve understanding of the region's responsibilities. Results of a spatial distribution analysis show that the eastern area of China leads in fossil energy consumption (e.g., coal and crude oil), whereas western China is the largest consumer of natural gas. Spatial relationship analyss indicate that eastern areas are located at the top of the trophic structure, implying that these regions are prioritized in energy consumption over the surrounding regions. By contrast, most regions located in the northern parts of China are characterized by resource-abundant areas and are at the bottom of the trophic structure, thereby indicating their comparatively weak role in an exploitation relationship. An investigation of major metropolitan areas demonstrates that mandatory targets set by national instruments are stratified in accordance with their diverse role and status in energy consumption at the beginning of the 12th Five-Year Plan period. However, these targets remain insignificant in the context of the inner area., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Offshore oil/gas productions are power intensive and CO 2 emitters from gas-fired power generation. This work investigates supersonic separator as a strategy for affording post-combustion capture backed up by cost reductions. Conventional offshore gas processing usually loses thermodynamic hydrate inhibitor methanol in processing and exported gas. This work analyses a supersonic separator variant gas processing simultaneously reducing methanol losses. Such process dramatically improves gas-plant profitability via cost-reduction of methanol make-up and power-consumption, simultaneously increasing revenues from liquefied-petroleum-gas by-product. This economic leverage affords post-combustion carbon capture, including subsequent CO 2 dehydration and compression for exportation of high-pressure liquid CO 2 . This corresponds to abate 43% of CO 2 emissions boosting revenues via enhanced oil recovery. Moreover, CO 2 is dehydrated via another supersonic separator operating with minimum head-loss, minimizing compression costs. Despite its much higher investment, the new process with carbon capture presents higher net value (865.63 MMUSD) than the conventional processing without carbon capture (829.31 MMUSD), being economically feasible and more environmentally adequate with cleaner natural gas production and successful CO 2 management. The new process is superior in several scenarios and particularly favored by oil prices above 55 USD/bbl. Rising oil price from 40 to 100 USD/bbl, the new process net value rises 29%, whereas the conventional counterpart rises only 7.5%. In addition, as a plausible future scenario, CO 2 taxation favors the new process, which always has superior economic performance, even without CO 2 taxation. In summary, implementing supersonic separators in offshore natural gas processing aiming at anti-hydrate recovery and CO 2 dehydration for enhanced oil recovery creates economic leverage sustaining Carbon Capture & Storage without loss of competitiveness. This result, backed up by rigorous thermodynamic simulations and economic-environmental assessments, configure an original achievement to the literature., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Light hydrocarbons accumulated in subsurface soil by long-term microseepage could favor the anomalous growth of indigenous hydrocarbon-oxidizing microorganisms, which could be crucial indicators of underlying petroleum reservoirs. Here, Illumina MiSeq sequencing of the 16S rRNA gene was conducted to determine the bacterial community structures in soil samples collected from three typical oil and gas fields at different locations in China. Incubation with n-butane at the laboratory scale was performed to confirm the presence of "universal microbes" in light-hydrocarbon microseepage ecosystems. The results indicated significantly higher bacterial diversity in next-to-well samples compared with background samples at two of the three sites, which were notably different to oil-contaminated environments. Variation partitioning analysis showed that the bacterial community structures above the oil and gas fields at the scale of the present study were shaped mainly by environmental parameters, and geographic location was able to explain only 7.05% of the variation independently. The linear discriminant analysis effect size method revealed that the oil and gas fields significantly favored the growth of Mycobacterium, Flavobacterium, and Pseudomonas, as well as other related bacteria. The relative abundance of Mycobacterium and Pseudomonas increased notably after n-butane cultivation, which highlighted their potential as biomarkers of underlying oil deposits. This work contributes to a broader perspective on the bacterial community structures shaped by long-term light-hydrocarbon microseepage and proposes relatively universal indicators, providing an additional resource for the improvement of microbial prospecting of oil and gas.

In this paper, a single-slope tunnel pipeline was analysed considering the effects of vertical earth pressure, horizontal soil pressure, inner pressure, thermal expansion force and pipeline-soil friction. The concept of stagnation point for the pipeline was proposed. Considering the deformation compatibility condition of the pipeline elbow, the push force of anchor blocks of a single-slope tunnel pipeline was derived based on an energy method. Then, the theoretical formula for this force is thus generated. Using the analytical equation, the push force of the anchor block of an X80 large-diameter pipeline from the West-East Gas Transmission Project was determined. Meanwhile, to verify the results of the analytical method, and the finite element method, four categories of finite element codes were introduced to calculate the push force, including CAESARII, ANSYS, AutoPIPE and ALGOR. The results show that the analytical results agree well with the numerical results, and the maximum relative error is only 4.1%. Therefore, the results obtained with the analytical method can satisfy engineering requirements.

Following the unconventional gas revolution, the forecasting of natural gas prices has become increasingly important because the association of these prices with those of crude oil has weakened. With this as motivation, we propose some modified hybrid models in which various combinations of the wavelet approximation, detail components, autoregressive integrated moving average, generalized autoregressive conditional heteroskedasticity, and artificial neural network models are employed to predict natural gas prices. We also emphasize the boundary problem in wavelet decomposition, and compare results that consider the boundary problem case with those that do not. The empirical results show that our suggested approach can handle the boundary problem, such that it facilitates the extraction of the appropriate forecasting results. The performance of the wavelet-hybrid approach was superior in all cases, whereas the application of detail components in the forecasting was only able to yield a small improvement in forecasting performance. Therefore, forecasting with only an approximation component would be acceptable, in consideration of forecasting efficiency.

Introduction: Cardiovascular diseases (CVD) remain the biggest cause of disability and premature death throughout the world., Aim: The aim of this study was to describe and determine the prevalence of major cardiovascular risk factors emerged at the first medical examination carried out by a group of an oil and gas contractor company workers in the observation period 2000-2010., Methods: An observational cross-sectional study was conducted on 1073 workers (mean age 41 years, SD = 9.5) presenting overweight BMI (body mass index) values, hypertension and cholesterol problems., Results: In particular, we found that workers > 45 years had significant higher risk to have obesity (OR = 3.8, CI 95% = 2.5-5.7), hypertension (OR = 2.7, CI 95% = 2.1-3.6), high blood fasting glucose (OR = 2.6, CI 95% = 1.2-5.5), high cholesterol (OR = 2.7, CI 95% = 2.0-3.6), high triglycerides (OR = 1.8, CI 95% = 1.4-2.4) compared to younger (< 45 years).

Hydraulic fracturing for natural gas extraction from shale produces waste brine known as flowback that is impounded at the surface prior to reuse and/or disposal. During impoundment, microbial activity can alter the fate of metals including radionuclides, give rise to odorous compounds, and result in biocorrosion that complicates water and waste management and increases production costs. Here, we describe the microbial ecology at multiple depths of three flowback impoundments from the Marcellus shale that were managed differently. 16S rRNA gene clone libraries revealed that bacterial communities in the untreated and biocide-amended impoundments were depth dependent, diverse, and most similar to species within the taxa γ-proteobacteria, α-proteobacteria, δ-proteobacteria, Clostridia, Synergistetes, Thermotogae, Spirochetes, and Bacteroidetes. The bacterial community in the pretreated and aerated impoundment was uniform with depth, less diverse, and most similar to known iodide-oxidizing bacteria in the α-proteobacteria. Archaea were identified only in the untreated and biocide-amended impoundments and were affiliated to the Methanomicrobia class. This is the first study of microbial communities in flowback water impoundments from hydraulic fracturing. The findings expand our knowledge of microbial diversity of an emergent and unexplored environment and may guide the management of flowback impoundments., (© 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.)

Energy production in the United States is in transition as the demand for clean and domestic power increases. Wind energy offers the benefit of reduced emissions, yet, like oil and natural gas, it also contributes to energy sprawl. We used a diverse set of indicators to quantify the ecological impacts of oil, natural gas, and wind energy development in Colorado and Wyoming. Aerial imagery was supplemented with empirical data to estimate habitat loss, fragmentation, potential for wildlife mortality, susceptibility to invasion, biomass carbon lost, and water resources. To quantify these impacts we digitized the land-use footprint within 375 plots, stratified by energy type. We quantified the change in impacts per unit area and per unit energy produced, compared wind energy to oil and gas, and compared landscapes with and without energy development. We found substantial differences in impacts between energy types for most indicators, although the magnitude and direction of the differences varied. Oil and gas generally resulted in greater impacts per unit area but fewer impacts per unit energy compared with wind. Biologically important and policy-relevant outcomes of this study include: 1) regardless of energy type, underlying land-use matters and development in already disturbed areas resulted in fewer total impacts; 2) the number and source of potential mortality varied between energy types, however, the lack of robust mortality data limits our ability to use this information to estimate and mitigate impacts; and 3) per unit energy produced, oil and gas extraction was less impactful on an annual basis but is likely to have a much larger cumulative footprint than wind energy over time. This rapid evaluation of landscape-scale energy development impacts could be replicated in other regions, and our specific findings can help meet the challenge of balancing land conservation with society's demand for energy.

A refinery located on the slopes of a mountain range in the city of Cubatão (SE-Brazil) is the main source of sulfur dioxide (SO(2)) in the region. For this reason, the refinery replaced a system in which energy was produced from crude oil combustion in boilers with a system of energy and vapor co-generation in a thermoelectric power plant fueled by natural gas. The aim of this study was to investigate the responses of Tibouchina pulchra to the fuel switching. Saplings planted in pots were distributed throughout monitoring sites around the polluting source (sites I, II, III and IV) and in a site (V) far from emissions. Changes on the plants responses occur along the three fuel switching phases. During the last phase, increased carbon assimilation (Asat) and decreased stomatal conductance (gs) were observed in plants growing in sites II and III; as a consequence, intrinsic water use efficiency (iWUE) increased. However, the increase in Asat did not promote growth increase suggesting that changes at the refinery did not result in better air quality, but only in a change in the main contaminants., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Naturally occurring radioactive materials (NORM) have been determined in fly and bottom ash collected from four major Syrian power plants fired by heavy oil and natural gas. (210)Pb and (210)Po were the main NORM radionuclides detected in the fly and bottom ash. (210)Pb activity concentrations have reached 3393±10 Bq kg(-1) and 4023±7 Bq kg(-1) in fly ash and bottom ash, respectively; lower values of (210)Po were observed due to its high volatility. In addition, (210)Po and (210)Pb annual emissions in bottom ash from mixed (heavy oil and natural gas) fired power plants varied between 2.7×10(9)-7.95×10(9) Bq and 3.5×10(9)-10(10) Bq, respectively; higher emissions of (210)Po and (210)Pb from gas power plants being observed. However, the present study showed that (210)Po and (210)Pb emissions from thermal power plants fired by natural gas are much higher than the coal power plants operated in the World., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

This study investigates the relationship between consumer sentiment (CONS), inflation expectations (INEX) and international energy prices, drawing on principles from behavioral. We focus on Brent crude oil price and Henry Hub natural gas prices as key indicators of energy market dynamics. Based on the monthly data from January 2003 to March 2023, three wavelet methods are applied to examine the time-frequency linkage, while the nonlinear distributed lag model (NARDL) is used to verify the asymmetric impact of two factors on energy prices. The results highlight a substantial connection between consumer sentiment, inflation expectations and international energy prices, with the former in the short term and the latter in the medium to long term. Especially, these correlations are particularly pronounced during the financial crisis and global health emergencies, such as the COVID-19 epidemic. Furthermore, we detect short-term asymmetric effects of consumer sentiment and inflation expectations on Brent crude oil price, with the negative shocks dominating. The positive effects of these factors on oil prices contribute to observed long-term asymmetry. In contrast, inflation expectations have short-term and long-run asymmetric effects on natural gas price, and both are dominated by reverse shocks, while the impact of consumer sentiment on natural gas prices appears to be less asymmetric. This study could enrich current theories on the interaction between the international energy market and serve as a supplement to current literature. [ABSTRACT FROM AUTHOR]

In this study, we conducted an in-depth analysis of the dynamic cointegration relationship between international crude oil, natural gas, and coal price indices from 2009 to 2023, revealing the changes and differences in the cointegration relationship between these three prices during different periods. Utilizing statistical analysis and economic modeling, we found significant cointegration among these energy prices during the initial decade-long observation period, indicating their close interaction in the global energy market influenced by supply and demand fundamentals, macroeconomic conditions, and geopolitical landscapes. However, since 2020, this long-standing stable cointegration relationship has been severely disrupted due to the global spread of the COVID-19 pandemic and escalating geopolitical tensions, leading to a notable increase in volatility and uncertainty in the energy market. Further analysis highlights that, in recent years, with the strengthening of global climate governance and the advancement of the low-carbon transition trend, fossil fuel markets, particularly high-carbon-emitting crude oil and coal markets, have undergone significant adjustments. Meanwhile, the role of natural gas as a transitional clean energy source has become increasingly prominent. The findings of this study have significant implications for energy policy formulation, market risk management, and strategic planning in the energy industry, while providing directions for future research on resilience and adaptability in the transition process of energy systems. [ABSTRACT FROM AUTHOR]

Miscible gas injection in tight/shale oil reservoirs presents a complex problem due to various factors, including the presence of a large number of nanopores in the rock structure and asphaltene and heavy components in crude oil. This method performs best when the gas injection pressure exceeds the minimum miscibility pressure (MMP). Accordingly, accurate calculation of the MMP is of special importance. A critical issue that needs to be considered is that the phase behavior of the fluid in confined nanopores is substantially different from that of conventional reservoirs. The confinement effect may significantly affect fluid properties, flow, and transport phenomena characteristics in pore space, e.g., considerably changing the critical properties and enhancing fluid adsorption on the pore wall. In this study, we have investigated the MMP between an asphaltenic crude oil and enriched natural gas using Peng-Robinson (PR) and cubic-plus-association (CPA) equations of state (EoSs) by considering the effect of confinement, adsorption, the shift of critical properties, and the presence of asphaltene. According to the best of our knowledge, this is the first time a model has been developed considering all these factors for use in porous media. We used the vanishing interfacial tension (VIT) method and slim tube test data to calculate the MMP and examined the effects of pore radius, type/composition of injected gas, and asphaltene type on the computed MMP. The results showed that the MMP increased with an increasing radius of up to 100 nm and then remained almost constant. This is while the gas enrichment reduced the MMP. Asphaltene presence changed the trend of IFT reduction and delayed the miscibility achievement so that it was about 61% different from the model without the asphaltene precipitation effect. However, the type of asphaltene had little impact on the MMP, and the controlling factor was the amount of asphaltene in the oil. Moreover, although cubic EoSs are particularly popular for their simplicity and accuracy in predicting the behavior of hydrocarbon fluids, the CPA EoS is more accurate for asphaltenic oils, especially when the operating pressure is within the asphaltene precipitation range. [ABSTRACT FROM AUTHOR]

It is well known that the existing horizontal-well-drilling and hydraulic fracturing technology used to achieve large-scale, cost-effective production from immature to low–moderate-maturity continental shale in China, where the organic matter mainly exists in solid form, is fairly ineffective. To overcome the obstacles, in situ conversion technology seems feasible, while implementing it in the target layer along with estimating the amount of expected recoverable hydrocarbon in such shale formations seems difficult. This is because there are no guidelines for choosing the most appropriate method and selecting relevant key parameters for this purpose. Hence, based on thermal simulation experiments during the in situ conversion of crude oil from the Triassic Chang 73 Formation in the Ordos Basin and the Cretaceous Nenjiang Formation in the Songliao Basin, this deficiency in knowledge was addressed. First, relationships between the in situ-converted total organic carbon (TOC) content and the vitrinite reflectance (Ro) of the shales and between the residual oil volume and the hydrocarbon yield were established. Second, the yields of residual oil and in situ-converted hydrocarbon were measured, revealing their sensitivity to fluid pressure and crude oil density. In addition, a model was proposed to estimate the amount of in situ-converted hydrocarbon based on TOC, hydrocarbon generation potential, Ro, residual oil volume, fluid pressure, and crude oil density. Finally, a method was established to determine key parameters of the final hydrocarbon yield from immature to low–moderate-maturity organic material during in situ conversion in shales. Following the procedure outlined in this paper, the estimated recoverable in situ-converted oil in the shales of the Nenjiang Formation in the Songliao Basin was estimated to be approximately 292 × 108 tons, along with 18.5 × 1012 cubic meters of natural gas, in an area of approximately 8 × 104 square kilometers. Collectively, the method developed in this study is independent of the organic matter type and other geological and/or petrophysical properties of the formation and can be applied to other areas globally where there are no available in situ conversion thermal simulation experimental data. [ABSTRACT FROM AUTHOR]

Although the recent debate in energy economics on the importance of oil price indexation versus shale gases suggest that big data can be used in predictive analysis in energy economics, little is known particularly in the context of shale gas and oil price interlinkages. Grounding our investigations in such directions we investigate in this paper the relationship between gas and crude oil markets and the impact US shale gas by employing time-varying causality method by Shi et al. (J Time Ser Anal 39(6):966–987, 2018; J Financ Econom 18(1):158–180, 2020) and cross-quantilogram correlation approach by Han et al. (J Econom 193(1):251–270, 2016). In particular, as a representative of the crude oil market, we use OPEC oil; WTI; Crude oil Oman; Crude oil Dubai while for the gas market, we use natural gas prices of UK NBP (National Balancing Point), NYMEX HH (Henry Hub) and US shale gas prices. Data period is from 11th January 2013 to 8th September 2020. We find significant negative spillovers from crude oil markets to natural gas markets particularly during moderate market conditions. The results suggest crucial implications in energy economics literature, to diversify assets to hedge against risks. We further find strong causality association between oil markets, natural gas markets and further oil markets and shale gas markets. Our findings describe that aftermath of the shale-gas boom the predictability nexus between oil and natural gas increased. Once we condition for shale gas the significant negative spill overs from oil markets to natural gas markets increases in the long-run. We suggest important policy prescriptions which have interconnected market repercussions. [ABSTRACT FROM AUTHOR]

Accurate and comprehensive quantification of oil and gas methane emissions is pivotal in informing effective methane mitigation policies, while also supporting the assessment and tracking of progress towards emissions reduction targets set by governments and industry. While national bottom-up source-level inventories are useful for understanding the sources of methane emissions, they are often unrepresentative across spatial scales, and their reliance on generic emission factors produces underestimations when compared with measurement-based inventories. Here, we compile and analyze previously reported ground-based facility-level methane emissions measurements in the major US oil and gas producing basins and develop representative methane emission profiles for key facility categories in the US oil and gas supply chain, including well sites, natural gas compressor stations, processing plants, crude oil refineries, and pipelines. We then integrate these emissions data with comprehensive spatial data on national oil and gas activity to estimate each facility's mean total methane emissions and uncertainties, from which we develop a mean estimate of national methane emissions, resolved at 0.1° × 0.1° spatial scales (~10 km × 10 km). From this measurement-based methane emissions inventory (EI-ME), we estimate total US national oil/gas methane emissions of 15.7 Tg (95 % confidence interval of 14–18 Tg) in 2021 which is 2.5 times greater than the EPA Greenhouse Gas Inventory. Our estimate represents a mean gas production-normalized methane loss rate of 2.6 %, consistent with recent satellite-based estimates. We find significant variability in both the magnitude and spatial distribution of basin-level methane emissions, ranging from <1 % methane loss rates in the gas-dominant Appalachian and Haynesville regions to >3–6 % in oil-dominant basins, including the Permian, Bakken, and the Uinta. Additionally, we present and compare novel comprehensive wide-area airborne remote sensing data and results of total area methane emissions and the relative contributions of diffuse and concentrated methane point sources as quantified using MethaneAIR in sub-regions of the Permian and Uinta basins that together indicate diffuse area sources accounting for the majority of total regional oil and gas emissions. Our assessment offers key insights into plausible underlying drivers of basin-to-basin variabilities in oil and gas methane emissions, emphasizing the importance of integrating measurement-based data in developing high-resolution, spatially explicit methane inventories in support of accurate methane assessment, attribution, and mitigation. The high-resolution spatially explicit EI-ME inventory is publicly available at https://doi.org/10.5281/zenodo.10734300 (Omara et al. 2024). [ABSTRACT FROM AUTHOR]

Ultra‐deep Sinian carbonate rocks are rich in natural gas, and the Deng‐4 Member of the Central Sichuan Basin has been shown to have an extremely high degree of thermal evolution. They are characterized by dry gas produced due to the thermal cracking of palaeo‐oil reservoirs (PORs). The distribution of PORs as materials for the formation of cracked gas reservoirs remains unclear. The complex multistage evolution process and limited drilling data make it challenging to precisely and systematically recover a range of PORs. Based on basin and petroleum system modelling (BPSM), the bottom‐up migration and accumulation method was used to investigate the distribution of PORs. Research shows that the PORs in the Sinian Deng‐4 Member were mainly formed in the Early–Middle Triassic under the mixed contribution of Cambrian and Sinian source rocks, and the coupling of palaeostructural and trap settings controlled its accumulation. Generally, the distribution of PORs can be divided into two categories: one is located at the core of the uplift zone and is controlled by structural‐stratigraphic composite traps, whereas the other is controlled by a series of lithologic traps formed in the slope area. Sensitivity analysis showed that the distribution patterns of the PORs were mostly related to the facies conditions (physical characteristics) of the reservoirs. The widely distributed PORs provide necessary and sufficient material conditions for the formation of cracked Sinian gas reservoirs in the Central Sichuan Basin, and the North Slope area has great potential for natural gas exploration in the future. [ABSTRACT FROM AUTHOR]

Miscible natural gas injection is widely considered as a practical and efficient enhanced oil recovery technique. However, the main challenge in this process is the high minimum miscibility pressure (MMP) between natural gas and crude oil, which limits its application and recovery factor, especially in hightemperature reservoirs. Therefore, we present a novel investigation to quantify the effect of chemicalassisted MMP reduction on the oil recovery factor. Firstly, we measured the interfacial tension (IFT) of the methane-oil system in the presence of chemical or CO2 to calculate the MMP reduction at a constant temperature (373K) using the vanishing interfacial tension (VIT) method. Afterwards, we performed three coreflooding experiments to quantify the effect of MMP reduction on the oil recovery factor under different injection scenarios. The interfacial tension measurements show that adding a small fraction (1.5 wt%) of the tested surfactant (SOLOTERRA ME-6) achieved 9% of MMP reduction, while adding 20 wt% of CO2 to the methane yields 13% of MMP reduction. Then, the coreflooding results highlight the significance of achieving miscibility during gas injection, as the ultimate recovery factor increased from 65.5% under immiscible conditions to 77.2% using chemical-assisted methane, and to 79% using gas mixture after achieving near miscible condition. The results demonstrate the promising potential of the MMP reduction to significantly increase the oil recovery factor during gas injection. Furthermore, these results will likely expand the application envelop of the miscible gas injection, in addition to the environmental benefits of utilizing the produced gas by re-injection/recycling instead of flaring which contributes to reducing the greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

In the southern thrust belt (STB) of Junggar Basin, hydrocarbon resources are abundant at ultradeep depths. The genesis of highly mature oil and gas is complex, with considerable geological implications, because of the burial depth of these resources and multiphase tectonic evolution. The deep–ultradeep oil and gas reservoir accumulation processes and the contribution of Permian source rocks are still unclear in the STB. In this study, using the ultradeep reservoirs of the middle section of the STB (MSTB) as an example, systematic evaluations were conducted on the hydrocarbon geochemical characteristics of the area. Additionally, this study detailed the accumulation and evolution processes of the reservoir in the lower play of the MSTB using various comprehensive technical analyses, such as those for the geochemical characteristics of crude oil, the genesis and source of crude oil and gas, inclusion observations, homogenization temperature, quantitative particle fluorescence, and basin simulation. The integrated analysis results showed that the oil and gas from Well HT-1 in Huxi Anticline (HXA) in the lower play was characterized by mixed sources from Permian argillaceous source rock and Jurassic coal-bearing source rocks. The pristane/phytane ratio (Pr/Ph) and biomarkers of the crude oil indicated the presence of Permian source crude oil. The natural gas drying coefficient and the carbon isotope of methane conveyed a typical coal-related gas from the Lower–Middle Jurassic epoch. In addition, three types of hydrocarbon inclusions (yellow–green fluorescence, blue–white fluorescence, and gaseous hydrocarbons) were developed in the MSTB. Oil and gas accumulation periods included Early Cretaceous, Eocene, and Miocene. Finally, substantial deviations were found for accumulation periods from different anticlines in the study area, which were controlled by the ancient structural background and tectonic evolution. The early anticlines, formed by Yanshanian tectonic movement (YSTM), controlled the early hydrocarbon migration as well as reservoir formation, and the newer anticlines, formed by Himalayan tectonic movement (HMTM), controlled the redistribution of hydrocarbons from ancient reservoirs. The oil and gas reservoir formed in Qingshuihe Formation (K1q) in HXA occurred during the Miocene. The ancient oil reservoirs to the south of HXA were damaged, and hydrocarbons were redistributed; the hydrocarbons migrated and accumulated in HXA and mixed with highly mature gas from Jurassic source rocks. The Permian hydrocarbons made a substantial contribution to the deep–ultradeep resources of MSTB and provided extremely rich hydrocarbon resources together with the Jurassic source rocks. Additionally, within MSTB, large anticlines were thoroughly developed in ultradeep strata, which provided superior trapping conditions for large-scale hydrocarbon accumulation. [ABSTRACT FROM AUTHOR]

This paper examines spillover from financial exchange-traded funds (ETF) futures to energy ETF futures using adjusted daily data extending from April 2, 2009, to November 23, 2020. We also explore the portfolio hedging-based conditional variance and co-variance derived from dynamic conditional correlation. The proxies for the financial ETF futures are financial select sector SPDR fund (XLF) and generic 1st S&P 500 index futures (SP1) while generic 1st crude oil WTI futures (CL1), generic 1st natural gas futures (NG1), and energy select SPDR fund (XLE) are proxies of energy ETF futures. The results obtained from Granger causality indicate that there is unidirectional causality from RXLF to RSP1 while bidirectional causality between RXLF and RCL1 at a 5% significance level. Further, dynamic conditional correlation indicates the spillover effect from RXLF to RCL1, RXLF to RXLE, RSP1 to RCL1, and RSP1 to RXLE both in the short-run and long run. The spillover from RXLF to RNG1 is witnessed only in the short run while the spillover from RSP1 to RNG1 is present in long run. The present study corroborates with the studies of Chang et al. (Int J Finan Stud 6(2): 1–24, 2018) and Lau et al. (Int Rev Finan Anal 52: 316-332, 2017). We notice that the average optimal hedge ratio of the RXLF/RNG1 pair is the most expensive while the cheapest hedging strategy is of RSP1/RCL1 pair. [ABSTRACT FROM AUTHOR]

Determining which variables affect price realized volatility has always been challenging. This paper proposes to explain how financial assets influence realized volatility by developing an optimal day-to-day forecast. The methodological proposal is based on using the best econometric and machine learning models to forecast realized volatility. In particular, the best forecasting from heterogeneous autoregressive and long short-term memory models are used to determine the influence of the Standard and Poor's 500 index, euro–US dollar exchange rate, price of gold, and price of Brent crude oil on the realized volatility of natural gas. These financial assets influenced the realized volatility of natural gas in 87.4% of the days analyzed; the euro–US dollar exchange rate was the primary financial asset and explained 40.1% of the influence. The results of the proposed daily analysis differed from those of the methodology used to study the entire period. The traditional model, which studies the entire period, cannot determine temporal effects, whereas the proposed methodology can. The proposed methodology allows us to distinguish the effects for each day, week, or month rather than averages for entire periods, with the flexibility to analyze different frequencies and periods. This methodological capability is key to analyzing influences and making decisions about realized volatility. [ABSTRACT FROM AUTHOR]

The discovery of the Bozhong 19-6 gas field has opened a new frontier for deep gas exploration in the Bohai Bay Basin, with a great potential for further gas exploration. However, poor understanding of oil and gas origin has been limiting the exploration progress in this area. To clarify the origin of condensate oil and gas in Bozhong 19-6 gas field, this study adequately utilized the organic geochemical analysis data to investigate the composition and geochemical characteristics of condensate oil and natural gas, and analyzed the relationship between condensate oil and the three sets of source rocks in the nearby subsags. Results show that the lighter components dominate the condensate oil, with a forward type predominance. The parent material of crude oil was primarily deposited in a shallow, clay-rich, low-salinity, weakly reducing aquatic environment. The condensate and natural gas have similar parent source characteristics and maturity, with Ro ranging from 1.4% to 1.6%. Both are products of high maturity stage, indicating that they are hydrocarbon compounds produced by the same group of source rocks in the same stage. Oil-sources correlation shows that condensate oil and gas mainly originate from the source rocks of the third member of Shahejie Formation in the nearby subsags of the Bozhong 19-6 structural belt. [ABSTRACT FROM AUTHOR]

Copyright of Revista CEA is the property of Revista CEA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the associated gas of tight reservoirs, natural gas is abundant and noncorrosive, which is more suitable for the development of tight oil reservoirs in China. However, the mechanism of gas injection development is unclear, and the gas channeling is serious in tight reservoirs after fracturing. The water-alternating-gas (WAG) flooding is an effective means to delay gas channeling and improve oil recovery. Therefore, it is significant to clarify the mechanism of preventing gas channeling and recovering oil by water-alternation-natural gas (WANG) flooding. The WANG flooding experiments with different water–gas slugs were conducted in non-fracture and fractured tight cores. Besides, the oil distribution of different pore spaces of cores before and after displacement and the main contribution spaces on oil recovery were quantitatively analyzed by using nuclear magnetic resonance and core mercury porosimetry techniques. The results indicate that compared with natural gas flooding, the WANG flooding can retard gas channeling, increase formation energy, and enhance oil recovery by up to 14.1%, especially in fractured cores. Under the resistance of water slugs, the gas was allowed to enter smaller pores and its swept volume was expanded. Oil is mainly stored in mesopores (0.1–1 μm) and small pores (0.01–0.1 μm), accounting for over 90% of the total volume. The oil recovered mainly comes from mesopores, which accounts for over 75% of the total amount. Moreover, the WANG flooding strengthens the recovery of oil in mesopores and macropores (1–10 μm), but it also squeezes oil into small pores and micropores (0.001–0.01 μm). [ABSTRACT FROM AUTHOR]

During the WWI the oil needs of the Romanian army became essential in the context of the retreats towards Eastern Romania, in Moldova. Geologist lon Popescu-Voiteşti was asked to find solutions to increase the oil production and he proposed to deepen the wells of certain oilfields such as Solonj-Stăneşti or Zemes, with excellent results. Based on this precedent, for a quarter of a century, the geological scientist turned professor at the University of Cluj, remained concerned with the issue of hydrocarbon fields in Romania. The results of that work were included in a series of publications, the last book published just one year before his sudden death being a synthesis on this topic. This paper exposes the main ideas which can be find in the publications issued between 1916 and 1943, which explain Voitesti's proposed approaches to the professional challenges of the oil and gas fields in Romania [ABSTRACT FROM AUTHOR]

The carbon footprints are increasing in the environment at an alarming rate mainly due to unplanned human activities. The world's population will continue to grow at a rapid pace in the future. As a result, our future generations may find it difficult to live on this planet in a healthy manner. The world's developed and developing countries began to investigate various methods for reducing their carbon footprint. However, it will not be sustainable if it is also not economically viable. In this scenario, maintaining a good profit for businesses while reducing their carbon footprint necessitates a pragmatic strategy. In this article, we will try to find a way out that will provide us with a practical solution. We will simulate the profitability of an upstream oil manufacturer that has invested heavily in green technologies. Under a carbon tax system, we will use the production-inventory model. This system assumes that capital investment in green technology can reduce emissions, and increase profits. We used data from the Oil and Natural Gas Corporation of India, available in its annual reports. As a matter of fact, the Oil and Natural Gas Corporation of India accounts for 70% of crude oil production in India and is a major player in India's upstream oil companies. The results were quite encouraging, with deviations between expected and actual values being less than 10%. The findings also led us to believe that the excise duty and the pollution control tax levied in India can be regarded as a Green Tax or Carbon Tax. We used a published research model to find the optimal solution. [ABSTRACT FROM AUTHOR]

This research explores the spillover effects in the directional movement of returns and the persistence of shocks among three prominent energy spot markets: title transfer facility for natural gas, Brent crude oil and electricity markets from monthly price data spanning January 2010 to September 2022. Methodologically, we initially employ bivariate vector autoregressive models to detect potential lagged return effects from one spot market on another. Then, we examine the impact on the conditional mean returns and volatility across these spot markets using the standard dynamic conditional correlation (DCC) model, as well as the respective asymmetric (ADCC) and flexible (FDCC) extensions. In addition, we accommodate innovative insights that include recent datasets on the COVID-19 crisis and the Ukrainian war, which constitute a new addition to the existent literature. The empirical findings confirm the significant impact of these two unprecedented moments of contemporaneous history, given that both events are substantiated by an exponential increase in prices and by a rise in volatility. However, the effect on returns was not uniform across the time series. Specifically, there was a consistent increase in volatility for natural gas and electricity from the start of 2020 until the end of 2022, while Brent oil exhibited a substantial peak only in the first half of 2020. This study also reveals that previous lagged returns within each market, particularly for Brent oil and electricity, had statistically significant effects on current returns. There was also a robust unidirectional positive spillover effect from the Brent oil market to the returns of electricity and the natural gas markets. The study also reveals the presence of a weak positive autocorrelation between natural gas and electricity returns, and positive shocks to returns had a more pronounced impact on volatility compared to negative shocks across all the time series. [ABSTRACT FROM AUTHOR]

The Kuqa depression is an important oil and gas production area in western China, and there are abundant natural gas resources in the deep and ultra‐deep tight reservoirs. In this study, the accumulation law of deep oil and gas in the Kuqa depression has been systematically discussed based on the analysis of geochemical parameters, reservoir fluid inclusions and the recovery of burial‐thermal evolution history in different structural zones. The results show that the lacustrine mudstones of the Triassic Huangshanjie and Upper Jurassic Qiakemake formations in the Kuqa depression are the main oil‐generating source rocks, and the coal‐measure source rocks of the Middle and Lower Jurassic are the main gas‐generating source rocks. The oil and gas in the northern tectonic belt originated from the Huangshanjie and Yangxia formations have the characteristics of 'lower‐source and upper‐reservoir' and 'self‐generation and self‐storage'. The source rocks in the central tectonic belt are of high maturity and mainly generate natural gas, and a small amount of crude oil is derived from mudstones of the Jurassic Qiakemake Formation. The oil and gas in the southern slope belt are mainly derived from the source rocks of the Huangshanjie Formation, followed by the Jurassic source rocks. The ordered accumulation of oil and gas in the Kuqa depression is controlled by the effective spatiotemporal matching of multi‐stage tectonic evolution and hydrocarbon generation evolution of multi‐source rocks. Three spatiotemporal ordered hydrocarbon accumulation series have been proposed: early near‐source accumulation, late far and near‐source accumulation, and late upper‐near source accumulation. The piedmont belt is dominated by the near‐source continuous accumulation mode, the thrust belt is dominated by the ultra‐late upper source accumulation mode, and the slope belt is dominated by the late far‐source accumulation mode. Therefore, future exploration will focus on the tight lithologic reservoirs in the northern piedmont belt, the structural reservoirs in the central structural belt, and the unconformity hidden reservoirs in the southern slope belt. [ABSTRACT FROM AUTHOR]

Electricity is the core of every nation's socioeconomic development. Nigeria depends heavily on fossil fuel for electricity generation due to the vast deposits of crude oil and natural gas in the country. Nevertheless, the vast deposit of crude oil, Nigeria still generates less than 4000 MW of electricity with per capita consumption of about 0.03 kW. Hydropower, being one of the available sources of energy, can be transported instantaneously and pollution free to the consumers making it attractive as compared to other forms of energy. Hence, the authors reviewed the available literatures on hydropower generation to evaluate its sustainability in Nigeria context. The literature search was made as wide as possible to capture all relevant data required. The searches covered databases specific to scholarly articles on hydropower generation sustainability. From the studies, it is shown that the potentials of hydropower generation in Nigeria if fully exploited can significantly improve the energy mix of the country that would sustainably serve its population. [ABSTRACT FROM AUTHOR]

Purpose – Industrial tourism not only strives to preserve industrial heritage, but can also be a strategy for being familiar with the history of industry and attracting tourists to new destinations. This paper examines the issue of promoting petroleum industrial tourism in the case of Khuzestan, Iran. The research aims at determining appropriate strategies for promoting petroleum industrial tourism. Design/methodology/approach – The data were analysed through a strengths, weaknesses, opportunities, and threats (SWOT) model. Findings – The results revealed the competitive strategy as the best. Lastly, strategies such as: concentric diversification, joint venture strategy, conglomerate diversification and horizontal diversification were proposed as key solutions. The results support the view that establishing an exploratory ecomuseum in the territory of Khuzestan Province can be a suitable concentric diversification strategy towards petroleum industrial sustainable tourism in the future. Originality/value – The main originality of this paper includes linking tourism with the petroleum (oil and natural gas) industry and its natural landscapes for the first time in a case study. Therefore, the results of this research can extend the literature in this regards. Moreover, this paper attracts tourists to visit natural landscapes of petroleum heritage.

Copyright of Revista Ibero-Americana de Ciência da Informação is the property of Revista Ibero-Americana de Ciencia da Informacao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study empirically investigates the asymmetric effects of spot (future) prices and storage on rig counts in the US natural gas and crude oil markets from January 1986 to May 2020. It adopts the Nonlinear Autoregressive Distributed Lag (NARDL) model and establishes a flexible and efficient framework that measures the effects of positive and negative shocks in each of these variables on rig counts while modeling possible asymmetries in both the short and long term. For the natural gas market, the results reveal significant long-term asymmetric effects of spot (future) gas prices and storage on gas rigs. The positive and statistically significant cumulative effect of changes in natural gas storage suggests that larger natural gas storage has caused changes in the use of natural gas drilling rigs. For the crude oil market, we find significant short-term asymmetric effects of spot (future) gas prices and oil stocks on oil rigs. Furthermore, in addition to the optimal price and level of storage, the cost, as proxied by the interest rate, is a crucial determinant in rig drilling decision-making in the energy sector. [ABSTRACT FROM AUTHOR]

Liquefied petroleum gas (LPG) is a C3/C4's hydrocarbon mixture used as fuel gas, obtained through natural gas processing or crude oil refining. The Ecuadorian LPG production (~1.88 MMbbl/year) comes from the Shushufindi gas plant and the Esmeraldas refinery. However, LPG production cannot meet the Ecuadorian market demand, and over 90% of this commodity is imported. At the same time, the natural gas produced in the Amazon region is not fully valued. A significant quantity of the associated gas is flared (~100 MMscfd), representing wasted energy with a significant environmental impact. Therefore, this study aimed to develop a technical and economic assessment of the potential natural gas valuation in the Amazon region to increase LPG production. The study started with a detailed review of the associated gas produced in the Amazon region. The data were analyzed considering the geographic location of the hydrocarbon fields, molar composition, flowrates, and operational conditions. Then, a natural gas value chain visualization was proposed and technically analyzed. Finally, an economic feasibility (class V) study was conducted, considering a preliminary analysis of capital expenditure (CAPEX) and an economic balance. The outcome of this study showed that by processing 21.50 MMscfd of associated gas from the Sacha field, domestic LPG production could increase by 30.9%. The required infrastructure consists of conventional processes for natural gas processing, with an estimated CAPEX of 36.6 MMUSD. Furthermore, despite the domestic subsidies of commodities, the potential savings for the country would be 32.13 MMUSD/year, an alternative more economically viable than the current LPG imports. Thus, the investment cost will be justified. [ABSTRACT FROM AUTHOR]

A breakthrough has been made in the recent exploration of the deep oil and gas bearing system in the eastern belt around the Penyijingxi sag of the Junggar Basin. These reservoirs are characterized by mixed sources and multi-stage accumulation. However, this process has not been thoroughly investigated, limiting our understanding of the fundamental rules of hydrocarbon migration and accumulation and making it difficult to determine exploration plans. This study mainly reconstructs this process using biomarkers, carbon isotopes, light hydrocarbons, and fluid inclusions. According to the biomarkers and carbon isotopes for oil-source correlation, Permian crude oil is a mixed-source oil from the Fengcheng Formation (P1f) and the Xiawuerhe Formation (P2w) source rocks, while Jurassic crude oil originates from the P2w source rock. The carbon isotope and light hydrocarbon data demonstrate that Jurassic natural gas has a mixed-gas characteristic with a preponderance of coal-type gas, in contrast to Permian natural gas, which is primarily oil-type gas. The hydrocarbon charging events in the study area were reconstructed based on a comprehensive investigation of the hydrocarbon generation history of source rocks, the homogenization temperature of fluid inclusion, and the burial history of the reservoir. According to the model, the P1f and P2w source rocks have made contributions to the current regional oil reservoirs, which provides targets for future exploration. [ABSTRACT FROM AUTHOR]

This manuscript deals with a novel, nonlinear, and non-stationary stochastic model with symmetric, Laplacian distributed innovations. The obtained model, named Laplacian Split-BREAK (LSB) process, is intended for dynamic analysis of time series with pronounced and permanent fluctuations. By using the method of characteristic functions (CFs), the basic stochastic properties of the LSB process are proven, with a special emphasis on its asymptotic behaviour. The different procedures for estimating its parameters are also given, along with numerical simulations of the obtained estimators. Finally, it has been shown that the LSB process, as an adequate stochastic model, can be applied in the analysis of dynamics in the world market of crude oil and natural gas. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feixianguan Formation in the Eastern Sichuan Basin. This seriously restricts the study of natural gas dynamics in the Feixianguan Formation and thus hampers natural gas exploration in the region, so further study is urgently required. Using experimental tests of natural gas composition, stable isotopes, and noble gas isotopes with gas chromatography (GC) and mass spectrometry (MS) studies of source rock and reservoir asphalt saturated hydrocarbons, the natural gas geochemical characteristics, the genetic identification and a gas-source comparison of the Feixianguan Formation were studied. Then, constrained by the thermal history, the histories of gas generation and expulsion were restored by basin simulation technology. Finally, a gas accumulation model was established for the Feixianguan Formation. The results showed that (1) the H2S-rich and H2S-poor gas reservoirs of the Feixianguan Formation are distributed on the east and west sides of the Kaijiang-Liangping trough in the Eastern Sichuan Basin, respectively. The carbon and hydrogen isotope compositions of the natural gas in the gas reservoirs are generally heavy and have typical characteristics of high-maturity dry gas reservoirs. (2) The natural gas of the Feixianguan Formation is organic thermogenic gas, which is mainly oil-type gas generated by the secondary cracking of crude oil. The gas-generating parent material is mainly type II kerogen. (3) The natural gas of the Feixianguan Formation in the Eastern Sichuan Basin was mainly generated by argillaceous source rocks of the Upper Permian Longtan Formation. (4) Natural gas accumulation occurred as follows: the paleo-structure heights were filled with crude oil in the Early Jurassic, and paleo-oil reservoirs were formed in the Feixianguan Formation; during the Middle-Late Jurassic, the paleo-oil reservoirs were cracked when the reservoir temperatures rose above 160 °C, and paleo-gas reservoirs were formed. Since the end of the Late Jurassic, the paleo-gas reservoirs have been adjusted and reformed to form the present-day natural gas reservoirs. These results provide a basis for studying natural gas accumulation dynamics of the Feixianguan Formation in the Eastern Sichuan Basin. [ABSTRACT FROM AUTHOR]