Search Results (993)

This study presents an integrated petrophysical workflow for the comprehensive characterization of the Upper Dalan and Kangan carbonate gas reservoirs in the Shanul Field, southwest Iran. By combining advanced cross-plot techniques (including M-N, MID, and RHOma-Uma plots) with probabilistic porosity modeling calibrated to core data, this work achieves a higher-resolution discrimination of lithology and more robust estimation of fluid properties compared to conventional single-log approaches. The results reveal significant heterogeneity within both formations but demonstrate the superior reservoir quality of the Upper Dalan, particularly within the UD2 subzone, and in the Ka-2a subzone of the Kangan. The improved workflow enables more accurate zonation and identification of high-quality, productive intervals, supporting optimized field development strategies. These findings provide methodological advances for challenging and heterogeneous carbonate systems, offering a reference framework for similar reservoirs in the Zagros Basin and beyond. Full article

The Qiongdongnan Basin constitutes a sedimentary basin characterized by elevated temperatures, significant overpressures, and abundant hydrocarbons. Investigations within this basin have identified hydrothermal fluid movements linked to overpressure conditions, comprising two vertically separated overpressured intervals. The shallow overpressure compartment is principally caused by a combination of undercompaction and clay diagenesis. In contrast, the deeper high-pressure compartment results from hydrocarbon gas generation. Numerical pressure modeling indicates late-stage (post-5 Ma) development of significant overpressure within the deep compartment. It is proposed that accelerated subsidence in the Pliocene-Quaternary initiated substantial gas generation, thereby promoting the formation of the deep overpressured system. Multiple organic maturation parameters, combined with fluid inclusion microthermometry, reveal a thermal anomaly adjacent to the upper boundary of the deep overpressured zone. This anomaly indicates vertical transport of hydrothermal fluids ascending from the underlying high-pressure zone. Laser Raman spectroscopy confirms the presence of both hydrocarbons and carbon dioxide within these migrating fluids. Integration of fluid inclusion thermometry with burial history modeling constrains the timing of hydrocarbon-carrying fluid charge to the interval from 4.2 Ma onward, synchronous with modeled peak gas generation and a phase of pronounced overpressure buildup. We propose that upon exceeding the fracture gradient threshold, fluid pressure triggered upward migration of deeply sourced, hydrocarbon-enriched fluids through hydrofracturing pathways. This process led to localized dissolution and fracturing near the top of the deep overpressured system, while simultaneously facilitating significant hydrocarbon accumulation and forming preferential accumulation zones. These findings provide critical insights into petroleum exploration in overpressured sedimentary basins. Full article

Limited-Entry Liner (LEL) technology has emerged as a transformative solution for enhancing hydrocarbon recovery in unconventional reservoirs while addressing challenges in carbon sequestration. This review examines the role of LEL in optimizing acid stimulation, hydraulic fracturing and production optimization, focusing on its ability to improve fluid distribution uniformity in horizontal wells through precision-engineered orifices. By integrating theoretical models, experimental studies, and field applications, we highlight LEL’s potential to mitigate the heel–toe effect and reservoir heterogeneity, thereby maximizing stimulation efficiency. Based on a comprehensive review of existing literature, this study identifies critical limitations in current LEL models—such as oversimplified annular flow dynamics, semi-empirical treatment of wormhole propagation, and a lack of quantitative design guidance—and aims to bridge these gaps through integrated multiphysics modeling and machine learning-driven optimization. Furthermore, we explore its adaptability for controlled CO₂ injection in geological storage, offering a sustainable approach to energy transition. This work provides a comprehensive yet accessible overview of LEL’s significance in both energy production and environmental sustainability. Full article

With increasing global energy demand and depletion of onshore oil–gas resources, deep-sea hydrocarbon exploration and development have become strategically vital. As core subsea transportation equipment, the performance of helico-axial multiphase pumps directly determines the efficiency and economic feasibility of deep-sea extraction. However, non-uniform inflow patterns caused by uneven gas–liquid distribution in pipelines degrade pressure-boosting capability and reduce pump efficiency under actual operating conditions. To address this, an optimization method employing helical static mixers was developed. A mixer with a 180° helical angle was designed and installed upstream of the pump inlet. Numerical simulations demonstrate that the mixer enhances gas-phase distribution uniformity in stratified flow, improving efficiency and head across varying gas void fractions (GVFs). At a stratification height ratio (Ψ) of 0.32, efficiency increased by 15.41% and head rose by 15.64 m, while turbulent kinetic energy (TKE) at the impeller outlet decreased by up to 50%. For slug flow conditions, the mixer effectively suppressed gas volume fraction fluctuations, consistently improving efficiency under different slug flow coefficients (φ) with a maximum head increase of 9.82%. The optimized flow field exhibits uniform gas–liquid velocity distribution, stable pressure boosting, and significantly reduced TKE intensity within impeller passages. Full article

The Permian Kupferschiefer shale, a key stratigraphic unit within the Zechstein sequence of the Fore-Sudetic Monocline, represents both a metal-rich lithofacies and a potential source rock for hydrocarbon generation. This study presents a comprehensive geochemical characterization of selected Kupferschiefer samples obtained from the Legnica–Głogów Copper District (LGOM) and exploratory boreholes. Analytical methods included Rock-Eval pyrolysis, Py-GC/FID, elemental analysis, TG-FTIR, biomarker profiling, and stable carbon isotope measurements. Results indicate that the shales contain significant amounts of Type II and mixed Type II/III kerogen, derived primarily from marine organic matter with minor terrestrial input. The organic matter maturity, expressed by T_max, places most samples within the oil window. Rock-Eval S2 values exceed 60 mg HC/g rock in some samples, confirming excellent generative potential. Py-GC/FID data further support high hydrocarbon yields, particularly in samples from the CG-4 borehole and LGOM mines. The thermal decomposition of kerogen reveals multiple degradation phases, with evolved gas analysis identifying sulfur-containing compounds and hydrocarbons indicative of sapropelic origin. Isotopic compositions of bitumen and kerogen suggest syngenetic relationships and marine depositional settings, with samples from a North Poland borehole showing isotopic enrichment consistent with post-depositional oxidation. Kinetic parameters calculated using the Kissinger–Akahira–Sunose method demonstrate variable activation energies (107–341 kJ/mol), correlating with differences in organic matter composition and mineral matrix. The observed variability in geochemical properties highlights both regional and facies-dependent influences on the shale’s generative capacity. The study concludes that the Kupferschiefer in southwestern and northern Poland exhibits substantial hydrocarbon generation potential. This potential has been previously underestimated due to the unit’s thinness, but localized zones with high TOC, favorable kerogen type, and low activation energy could be viable exploration targets for natural gas. Full article

Indoor air pollution (IAP) has emerged as a critical yet underrecognized threat to public health, particularly in non-industrial environments such as homes, schools, and healthcare facilities. As individuals spend approximately 90% of their time indoors, exposure to indoor pollutants—such as particulate matter, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and microbial contaminants—can lead to significant health risks. These risks disproportionately affect vulnerable populations, including children, the elderly, and individuals with pre-existing conditions. The effects range from mild respiratory symptoms to severe outcomes like asthma, cardiovascular diseases, and cancer. This review investigates the sources, typologies, and health effects of indoor air pollutants, with a focus on their implications for maternal and child health. In particular, children’s developing systems and higher metabolic intake make them more susceptible to airborne toxins. The study also explores the legal and regulatory frameworks surrounding indoor air quality (IAQ), emphasizing how increased awareness and scientific evidence are expanding the scope of medical–legal responsibility. Legal liabilities may arise for property owners, designers, or manufacturers when poor IAQ leads to demonstrable health outcomes. Despite growing concern, there remains a significant research gap concerning the long-term health effects of chronic low-level exposure in residential settings and the efficacy of mitigation strategies. The evolution of smart building technologies and green construction practices offers promising avenues to improve IAQ while maintaining energy efficiency. However, standards and regulations often lag behind scientific findings, highlighting the need for updated, enforceable policies that prioritize human health. This work underscores the urgency of a multidisciplinary and preventive approach to IAQ, integrating public health, environmental engineering, and legal perspectives. Future research should focus on real-time IAQ monitoring, targeted interventions for high-risk populations, and the development of comprehensive legal frameworks to ensure accountability and promote healthier indoor environments. Full article

The Lower Submember of the Second Member of the Lianggaoshan Formation (LGS2-LS) in the Fuling area, southeastern Sichuan Basin, represents the deepest lacustrine depositional stage of the formation and constitutes an important target for shale oil and gas exploration. Based on core observations, thin-section petrography, X-ray diffraction, geochemical analyses, and sedimentary facies interpretation from representative wells, this study characterizes the lithofacies types, sedimentary environments, and depositional evolution of the LGS2-LS. Results show that the LGS2-LS is dominated by clay–quartz assemblages, with average clay mineral and quartz contents of 44.6% and 38.8%, respectively, and can be subdivided into shallow and semi-deep lacustrine subfacies comprising eight microfacies. Geochemical proxies indicate alternating warm-humid and hot-arid paleoclimatic phases, predominantly freshwater conditions, variable redox states, and fluctuations in paleoproductivity. Sedimentary evolution reveals multiple transgressive–regressive cycles, with Sub-layer 6 recording the maximum water depth and deposition of thick organic-rich shales under strongly reducing conditions. The proposed sedimentary model outlines a terrigenous clastic lacustrine system controlled by lake-level fluctuations, transitioning from littoral to shallow-lake to semi-deep-lake environments. The distribution of high-quality organic-rich shales interbedded with sandstones highlights the LGS2-LS as a favorable interval for shale oil and gas accumulation, providing a geological basis for further hydrocarbon exploration in the southeastern Sichuan Basin. Full article

The Baorao Trough of the Jiergalangtu Sag, located in the central Erlian Basin, is rich in petroleum resources. However, due to a lack of systematic geochemical characterization and comparative studies with other source rocks, the hydrocarbon generation potential of its Jurassic strata remains unclear. In this study, 125 samples from the Baorao Trough were analyzed to evaluate their hydrocarbon generation potential, identify organic matter sources and depositional environments, and characterize hydrocarbon generation and expulsion. Results show that source rocks from the first member of the Tengge’er (K₁bt₁) Formation and the Aershan (K₁ba) Formation have high organic matter content, favorable kerogen types, and have reached low to medium maturity. In contrast, Jurassic source rocks are predominantly Type III kerogen and highly mature. K₁bt₁ was deposited in a weakly oxidizing to reducing, brackish environment, while K₁ba formed under weakly reducing, saline conditions. Jurassic source rocks also developed in weakly reducing, brackish to saline settings. Notably, saline and reducing environments promote the development of high-quality source rocks. The lower total organic carbon (TOC) threshold for effective source rocks in the study area is 0.8%, and the hydrocarbon expulsion threshold for vitrinite reflectance ratio (R_o) is approximately 0.8%. Accordingly, K₁bt₁ and K₁ba have undergone partial hydrocarbon expulsion but remain within the oil-generating window, indicating strong oil-generating potential. Jurassic source rocks likely experienced early thermal cracking of Type III kerogen, with generated oil migrating or escaping during early geological activity. However, some gas-generating potential remains. These findings provide significant evidence for assessing resource potential, predicting the distribution of high-quality source rocks and favorable exploration areas. Full article

The East China Sea Shelf Basin (ECSSB) and its adjacent areas, as key regions of the ocean–continent transition zone, have been affected by multiple complex plate collisions, subduction, and back-arc tension since the Mesozoic Era. The structural deformation provides a large amount of geological information on the ocean–continent transition zone. There are significant spatiotemporal differences in the structural deformation within the basin. However, the research remains insufficient and understanding is inconsistent, especially regarding the systematic study of the differences and dynamic mechanisms of north–south structural deformation, which is relatively lacking. This study is based on two-dimensional multi-channel deep reflection seismic profiles spanning the southern and northern basin. Through an integrated re-analysis of gravity, magnetic, and OBS data, the deformation characteristics and processes of the Meso-Cenozoic structures in the basin are analyzed. The differences in structural deformation between the southern and northern basin are summarized, and the controlling effects of deep crust–mantle activity and the influencing factors of shallow structural deformation are explored. Based on deep reflection seismic profiles, the structural deformation characteristics of the Yushan–Kume fault are revealed for the first time, and it is proposed that NW faults, represented by the Yushan–Kume fault, have important tuning effects on the north–south structural differential deformation in the ECSSB. The thermal subsidence of the lithosphere is the direct cause of the development of the Mesozoic ECSSB, while the subduction of the Paleo-Pacific plate is one of the important factors contributing to it. The combined effect of the two has led to significant differences between the northern and southern Mesozoic basin. During the Cenozoic Era, the alternating subduction and changes in the direction of subduction of the Pacific Plate led to spatiotemporal differences in structural deformation within the ECSSB. The development of NW faults was a key factor in the differences in structural deformation between the northern and southern basin. The study of structural deformation differences in the ECSSB not only deepens our understanding of the tectonic evolution in the East Asian continental margin region, but also has important significance for the exploration and evaluation of deep hydrocarbon resources in the ECSSB. Full article

As traffic load continuously rises and climatic conditions increasingly vary, the performance of conventional base asphalt can no longer satisfy the needs of modern road engineering in low-temperature cracking resistance, high-temperature stability, and long-term durability. Therefore, the development of novel and efficient asphalt modifiers holds significant engineering value and practical importance. In this study, modified asphalt was prepared using varying dosages of ZM modifier (direct-injection asphalt mixture modified polymer additive). A series of experiments was executed to assess its influence on asphalt properties. First, fundamental property tests were implemented to determine the regulating effect of the ZM modifier on basic physical performances, like the softening point and penetration of the base asphalt. Penetration tests at different temperatures were performed to calculate the penetration index, thereby assessing the material’s temperature sensitivity. Subsequently, focusing on temperature as a key factor, tests on temperature sweep, and multiple stress creep recovery (MSCR) were implemented to delve into the deformation resistance and creep recovery behavior of the modified asphalt under high-temperature conditions. In addition, bending beam rheometer (BBR) experiments were introduced to attain stiffness modulus and creep rate indices, which were applied to appraise the low-temperature rheological performance. Aside from Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) was utilized to explore the mechanism by which the ZM modifier influences the asphalt’s functional group composition and microstructure. Our findings reveal that the ZM modifier significantly increases the asphalt’s softening point and penetration index, reduces penetration and temperature sensitivity, and enhances high-temperature stability. Under high-temperature conditions, the ZM modifier adjusts the viscoelastic balance of asphalt, hence enhancing its resistance to flow deformation and its capacity for creep recovery. In low-temperature environments, the modifier increases the stiffness modulus of asphalt and improves its crack resistance. FTIR analyses reveal that the ZM modifier does not introduce new functional groups, indicating a physical modification process. However, by enhancing the cross-linked structure and increasing the hydrocarbon content within the asphalt, it strengthens the adhesion between the asphalt and aggregates. Overall, the asphalt’s performance improvement positively relates to the dosage of the ZM modifier, providing both theoretical basis and experimental support for its application in road engineering. Full article

Air pollution is an escalating global challenge with profound implications for agricultural production and food security. This review explores the impacts of deteriorating air quality on global crop yields and food security, emphasizing both direct physiological effects on plants and broader environmental interactions. Key pollutants such as ground-level ozone (O₃), fine particulate matter (PM_2.5 and PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs) reduce crop yield and quality. They have been shown to inhibit plant growth, potentially by affecting germination, morphology, photosynthesis, and enzyme activity. PAH contamination, for example, can negatively affect soil microbial communities essential for soil health, nutrient cycling and organic matter decomposition. They persist and accumulate in food products through the food chain, raising concerns about food safety. The review synthesizes evidence demonstrating how air pollution undermines the four pillars of food security: availability, access, utilization, and stability by reducing crop yields, elevating food prices, and compromising nutritional quality. The consequences are disproportionately severe in low- and middle-income countries, where regulatory and infrastructural limitations exacerbate vulnerability. This study examines mitigation strategies, including emission control technologies, green infrastructure, and precision agriculture, while stressing the importance of community-level interventions and real-time air quality monitoring through IoT and satellite systems. Integrated policy responses are urgently needed to bridge the gap between environmental regulation and agricultural sustainability. Notably, international cooperation and targeted investments in multidisciplinary research are essential to develop pollution-resilient crop systems and inform adaptive policy frameworks. This review identifies critical knowledge gaps regarding pollutant interactions under field conditions and calls for long-term, region-specific studies to assess cumulative impacts. Ultimately, addressing air pollution is not only vital for ecosystem health, but also for achieving global food security and sustainable development in a rapidly changing environment. Full article

Reservoirs and caprocks overlap with each other in heterogeneous carbonate rocks. The sealing capacity of caprocks and their controlling factors are not clear, which restricts the prediction, exploration, and development of carbonate hydrocarbon reservoirs. We selected core samples from the Ordovician reservoirs and caprocks in the Tarim Basin, China, for scanning electron microscopy, thin section, breakthrough pressure (BP), high-pressure mercury intrusion porosimetry (HMIP), and nitrogen adsorption method (N₂GA). The experimental results show that the reservoir and caprock can be distinguished by BP. The BP of the reservoir is less than 3.0 MPa, and the BP of the caprock is less than 3.0 Mpa. We analyzed the heterogeneity characteristics and differences in reservoirs and caprocks with different lithologies from the perspectives of monofractal and multifractal. The results indicate that the differences in pore structure of grainstone, dolomite, and micrite/argillaceous limestone result in significant heterogeneity differences between samples. The correlation analysis between the fractal parameters and BP indicates that the characteristics of reservoir microporous structures have a decisive impact on BP (correlation coefficient > 0.7). The pore structure of the carbonate reservoir–caprock system exhibits self-similarity. The heterogeneity of the caprock has no significant control effect on BP (correlation coefficient < 0.3), while the higher the heterogeneity of the reservoir, the greater the BP. The sealing capacity of the caprock depends on the heterogeneity differences in pore types and pore structures between the reservoirs and caprocks. When both the reservoir and the caprock are grainstone, the micropores in the reservoirs and caprocks are dispersed but evenly distributed, and little heterogeneous differences can achieve sealing. When the lithology of reservoirs and caprocks is different, the enhancement of heterogeneity differences in micropores will improve the sealing capacity of the caprock. In summary, fractal dimension is an effective method for studying the heterogeneous structure and sealing capacity of pore–throat in carbonate caprocks. This study proposes a new perspective that the difference between the heterogeneity of micropore structures of reservoirs and caprocks affects the sealing capacity of carbonate rocks, and provides a new explanation and model for the sealing mode of carbonate rock caprocks. Full article

The Pinghu Oil and Gas Field in the East China Sea Shelf Basin represents a significant offshore hydrocarbon-producing region in East Asia. However, the Paleogene hydrocarbon system in the Pinghu Oil and Gas Field is complex, and the fluid properties, charging stages, and hydrocarbon accumulation process are still unclear. A comprehensive integrated analysis of the hydrocarbon accumulation characteristics, fluid properties, temperature pressure regimes, primary hydrocarbon sources and origins (genesis), charging stages, preservation conditions, and evolutionary history of hydrocarbon accumulation have been studied by utilizing a series of well data, oil and gas geochemical parameters, carbon isotope, and fluid inclusion analyses. Hydrocarbon charging in the Huagang Formation experienced one stage, and the crude oil is characterized as light and conventional, exhibiting low density and viscosity, a low pour point, and low contents of wax, resin, and sulfur. In contrast, the reservoir of the overpressured Pinghu Formation experienced a two-stage hydrocarbon charging process (oil filling and gas filling), exhibiting higher density, viscosity, and wax content compared to the Huagang Formation. The hydrocarbon charging and evolution process of the Pinghu Formation and Huagang Formation in the Pinghu Oil and Gas Field can be summarized in three different stages, including the oil filling period (10–5 Ma), gas filling period (5–2 Ma), and oil and gas adjustment period. The Pinghu Oil and Gas Field, especially in the lower Pinghu Slope Belt (Fangheting Structure), has good potential for further exploration. Full article

Phytoremediation is widely acknowledged as a viable method for soil remediation; however, its efficacy remains limited in soils co-polluted with petroleum hydrocarbons and heavy metals. To overcome this constraint, the present study explored an innovative approach utilizing ferrate-modified biochar (FeBC) to augment phytoremediation efficiency. Experimental findings revealed that ferrate treatment markedly modified the physicochemical characteristics of biochar, yielding thinner, smoother-surfaced structures with pronounced iron enrichment. At a 5% application rate alongside ryegrass cultivation, FeBC exhibited superior remediation performance, achieving 52.0% degradation of petroleum hydrocarbons (notably within the meso-aggregate fraction) and a 19.2% decline in zinc bioavailability via immobilization, thereby reducing zinc uptake in ryegrass tissues. Furthermore, FeBC amendment induced significant shifts in rhizosphere soil biochemistry and microbial ecology, characterized by diminished catalase activity but elevated urease and alkaline phosphatase activities. Phospholipid fatty acid profiling indicated a substantial rise in bacterial biomass (encompassing both Gram-positive and Gram-negative groups), particularly in meso- and micro-aggregates, whereas soil bacterial α-diversity declined markedly, accompanied by distinct compositional changes across aggregate size fractions. These results offer mechanistic insights into the synergistic interaction between FeBC and ryegrass in co-contaminated soil rehabilitation, the aggregate-dependent distribution of remediation effects, and microbial community adaptations to FeBC treatment. Collectively, this study advances the understanding of ferrate-modified biochar’s role in phytoremediation enhancement and clarifies its operational mechanisms in petroleum-zinc co-contaminated soil systems. Full article

The plants from the Ocimum genus, belonging to the Labiatae family, serve as important bioresources of essential oils (EOs) rich in biologically active secondary metabolites, widely used in medicine, food, and cosmetics. This study explored the volatile composition, enantiomeric distribution, and in vitro biological activities of EOs from three Ocimum species native to Nepal: O. tenuiflorum L., O. basilicum L., and O. americanum L. EOs were extracted via hydro-distillation and analyzed using gas chromatography–mass spectrometry (GC-MS) for chemical profiling and chiral GC-MS for enantiomeric composition. Hierarchical cluster analysis was performed for major chemotypes. Antioxidant activity was assessed using DPPH and ABTS assays. Antimicrobial efficacy was evaluated using the microbroth dilution method, and cytotoxicity was tested on NIH-3T3 (normal) and MCF-7 (breast cancer) cell lines via the Cell Counting Kit-8 assay. EO yield was highest in O. tenuiflorum (1.67 ± 0.13%) during autumn and lowest in O. americanum (0.35 ± 0.02%) during winter among all Ocimum spp. The major compounds identified in O. tenuiflorum were eugenol (32.15–34.95%), trans-β-elemene (29.08–32.85%), and β–caryophyllene (19.85–21.64%). In O. americanum, the major constituents included camphor (51.33–65.88%), linalool (9.72–9.91%), germacrene D (7.75–1.83%), and β–caryophyllene (6.35–3.97%). For O. basicilum, EO was mainly composed of methyl chavicol (62.16–64.42%) and linalool (26.92–27.05%). The oxygenated monoterpenes were a dominant class of terpenes in the EOs except for O. tenuiflorum (sesquiterpene hydrocarbon). A hierarchical cluster analysis based on the compositions of EOs revealed at least three different chemotypes in Ocimum species. Chiral GC-MS analysis revealed β-caryophyllene and germacrene D as enantiomerically pure, with linalool consistently dominant in its levorotatory form. O. tenuiflorum exhibited the strongest antimicrobial activity, particularly against Candida albicans, and showed notable anticancer activity against MCF-7 cells (IC₅₀ = 23.43 µg/mL), with lower toxicity to normal cells. It also demonstrated the highest antioxidant activity (DPPH IC₅₀ = 69.23 ± 0.10 µg/mL; ABTS IC₅₀ = 9.05 ± 0.24 µg/mL). The EOs from Ocimum species possess significant antioxidant, antimicrobial, and cytotoxic properties, especially O. tenuiflorum. These findings support their potential application as natural agents in medicine, food, and cosmetics, warranting further validation. Full article