Search Results (2,427)

Oil pollution remains a persistent global environmental challenge due to the recalcitrance and toxicity of lipid-rich contaminants in terrestrial and aquatic ecosystems. Bacterial lipases (EC 3.1.1.3) play a pivotal role in the initial stages of bioremediation by catalysing the hydrolysis of complex lipids into more bioavailable intermediates, thereby facilitating downstream microbial degradation and mineralisation. This review critically examines the mechanistic basis of lipase-mediated hydrocarbon degradation, with emphasis on enzyme structure–function relationships, catalytic pathways, and regulation under environmentally relevant conditions. In addition to conventional applications in soil and wastewater bioremediation, emerging strategies involving immobilised enzymes, microbial consortia, and waste-derived substrates are evaluated for their effectiveness and scalability. Attention is given to advances in molecular and omics approaches, including metagenomics, transcriptomics, and proteomics, which have expanded the discovery of novel lipases but remain limited in their ability to predict in situ functionality. The review highlights the growing role of protein engineering and artificial intelligence in tailoring lipase properties; however, it also critically assesses current limitations, including insufficient experimental validation and challenges in translating computational predictions to complex environmental systems. Furthermore, integrating multi-omics data into quantitative and predictive frameworks is identified as a key future direction for improving bioremediation efficiency. Despite significant progress, major gaps persist in linking enzyme activity to real-world degradation performance and in developing standardized, scalable approaches. This review therefore provides a comprehensive and critical synthesis of current knowledge while identifying strategic research priorities required to advance bacterial lipases as robust tools for sustainable bioremediation of lipid-based pollutants. Full article

The High Agri Valley (HAV, Southern Italy) comprises the largest onshore oil field in Europe and has both significant geothermal extraction potential and one of the highest seismic hazards in Italy, as demonstrated by the 1857 Mw 7.0 Basilicata earthquake. However, seismic imaging and geological mapping have so far produced insufficient evidence regarding the location of fluid reservoirs and human-induced migration pathways within the HAV’s tectonic structures. Here, a 3D scattering and absorption tomography, proxy for heterogeneities and fluid content, respectively, detects hydrocarbons and potential geothermal resources within the Apulian Platform. Seismic scattering differentiates the low-scattering Irpinia tectonic mélange, which deepens in the center of the valley, from the fractured high-scattering carbonates of the Apulian Platform. Seismic absorption identifies regions of fluid reinjection, as demonstrated by the Costa Molina 2 case study, and reveals the preferred pathways for fluids that induce seismicity due to seasonal variations in the water level of the Pertusillo artificial lake. The integration of scattering and absorption imaging with direct well information, geochemical and hydrological models, could provide a powerful tool for both seismic hazard assessment and the exploration of sustainable energy resources. Full article

Quintero is a Chilean coastal city located 40 km north of Valparaiso. In the surroundings of Quintero, there are a number of industries that generate high levels of atmospheric pollutants such as sulfur dioxide (SO₂), nitrogen oxides (NO_x), carbon monoxide (CO) and non-methane hydrocarbons (NMHCs). These compounds may also be generated during oil handling in storage facilities in this area. Quintero Bay has a port that is being used mainly for oil and copper transportation. Since 2010, there have been reports of events producing nausea, vomiting and abdominal pain in the residents of Quintero, and some previous studies have correlated these medical events with high concentrations of SO₂ and NMHCs. One of the main sources of SO₂ in the area was identified to be the Ventanas copper foundry. Following public pressure, the government stopped the operation of the foundry by mid-2023, which led to a significant decrease in SO₂ levels. However, reports of health problems persisted to some extent. In this work, delayed cross-correlation, trajectory and dispersion analyses indicate that an upwind source of air pollution impacting Quintero originates near the oil refinery in Concón, located 20 km to the south. This source of air pollution could provide a background of NMHCs, over which local emissions add up to attain very high concentrations in Quintero. Our analysis shows that there is evidence of the transport of NMHCs from the Concón refinery to the Quintero area. In 2022, of the 20 days with NMHC concentrations greater than 200 ppvb, 50% of them were associated with prevalent southwest winds. Using trajectory and dispersion analyses for eight episodes in Quintero, it has been found that an approximate fraction of pollution generated in Concón that could arrive in Quintero is between 2 and 24%. Full article

The Ediacaran Dengying Formation 2nd Member (hereafter 2nd Member) in the Sichuan Basin is influenced by major tectonic events including the Caledonian, Indosinian, and Himalayan orogenies and this strata has experienced a complex hydrocarbon accumulation history, resulting in inconsistent gas–water contacts. To elucidate this complex history, this study investigates the diagenetic mineral filling sequence within the Dengying 2nd Member in the Penglai area. We integrated data from analytical techniques such as cathodoluminescence (CL), in situ trace element analysis, U–Pb geochronology, and fluid-inclusion microthermometry. Based on these analyses, this study established the paragenetic sequence, incorporating both diagenesis and hydrocarbon accumulation, for the Dengying 2nd Member. This sequence comprises eight distinct phases of mineral precipitation and hydrocarbon emplacement: fibrous dolomite, granular dolomite, fine crystalline dolomite, first-phase bitumen, medium crystalline dolomite, saddle dolomite, second-phase bitumen, and quartz. From this sequence, we propose a four-stage hydrocarbon accumulation model for the Dengying Formation: (1) primary migration and accumulation during the Indosinian period; (2) oil cracking to gas during the Yanshanian period; and (3) and (4) two distinct stages of gas pool adjustment during the Himalayan period. Corresponding to these stages, this study developed distinct accumulation models and simulated migration and accumulation processes during key stages. The results indicate that the distribution of paleo-oil pools exerts significant control over the location of present-day gas accumulations. Initial oil charge was controlled by the distribution of carrier beds and hydrocarbon charging pathways, with water zones observed more frequently in the lower intervals of the Dengying 2nd Member. Subsequently, gas generated from oil-cracking filled these carrier beds, with areas of gas enrichment correlating with zones of high paleo-oil saturation. Finally, during the later adjustment stages, fault activity induced gas remigration and leakage, significantly impacting the final trapping configuration and preservation of gas accumulations. Full article

Aluminum alloys are attractive for oil production, refining, and hydrocarbon-processing equipment because of their low density, high specific strength, and heat-transfer properties; however, their use is limited by localized corrosion in chloride-, sulfur-, and water-containing environments. This review analyzes combined anodic oxide/polymer and anodic oxide/fluoropolymer coating systems as surface-engineering approaches for improving corrosion resistance, adhesion, and durability of aluminum alloys under such conditions. The reviewed data show that coating performance is governed by anodic oxide morphology, pore sealing or polymer impregnation, and oxide/polymer interfacial stability. Quantitative results indicate that anodizing and pore widening can increase aluminum/polyamide lap-shear strength from 5.0 to 17.4 MPa, while optimized interfacial treatment can provide 22.5 ± 0.5 MPa before aging and 18.1 ± 0.2 MPa after humid aging. Corrosion data show that anodizing can increase the polarization resistance of aluminum alloy 6061 in seawater from 17.2 kΩ·cm² to 2.24 MΩ·cm². For wear-related durability, optimized anodizing can increase the critical scratch load from 37.3 to 118.9 N. These values provide practical benchmarks for designing anodic oxide/polymer systems for complex oilfield and hydrocarbon-processing environments. Full article

Heavy and highly viscous oils account for a significant proportion of the world’s hydrocarbon reserves. The development of these reserves in harsh climates is associated with technological risks due to paraffin deposits and equipment corrosion. Ensuring reliable transportation requires operational monitoring of the physical and chemical properties of fluids directly at the wellhead. Traditional laboratory methods such as SARA fractionation and gas chromatography (GC) are time-consuming and can yield to distortions in the sample composition during transportation. Field optical methods, such as an infrared (IR) spectroscopy are complicated by the optical heterogeneity of crude oils due to emulsified water, supramolecular associations of resins, asphaltenes, and paraffins. In this paper, ultrasonic (US) sample preparation for high-viscosity oils is justified as a method for increasing the reliability and information content of field IR spectroscopic analysis by unmasking the diagnostic extrema of absorption bands that are initially distorted by emulsified water, baseline scattering, and radiation scattering from large resin–asphaltene–paraffin aggregates. The technique is based on cavitation-induced destruction of emulsion shells and disaggregation of the structural framework without volume thermal heating. Experimental data obtained from watered high-viscosity oil has shown that 9 min of the US exposure reduces the light scattering index $I_{\mathrm{t}\mathrm{r}\mathrm{s}}$ by 92.83%, bringing the system into a less heterogeneous state. Statistical correlation analysis confirmed that emulsions and aggregates are the main scattering centers, and their destruction correlates directly with the transparency of the medium. Stability of spectral indices $I_{{\mathrm{C}\mathrm{H}}_3/{\mathrm{C}\mathrm{H}}_2}$, $I_{\mathrm{f}\mathrm{o}\mathrm{c}}$ and $I_{\mathrm{C}=\mathrm{O}}$ indicates the absence of chemical degradation or oxidation at the US exposure intensity of 0.12 W/mL, confirming the physical nature of the effect. The proposed method makes it possible to implement automated monitoring of the properties of high-viscosity oil directly at the wellhead, minimizing logistic costs and risks of the sample degradation. The practical significance of the proposed method is to improve the reliability and information content of wellhead monitoring by reducing optical heterogeneity and making diagnostic significant IR absorption extremes more distinguishable for further interpretation. Full article

This study investigated the effects of environmental conditions on polycyclic aromatic hydrocarbon (PAH) emissions from scented candles during combustion. An exposure chamber was established and validated to ensure stability and uniformity before the experiments were conducted. One of the most widely used scented candles (paraffin wax + 6% lavender essential oil) was selected in the present study. Testing environmental conditions included three relative humidity (RH) levels (60%, 75%, and 90%) and three air exchange rates (ACHs) (0.5, 1.0, and 2.0 h⁻¹). For each tested environmental condition, three replicate measurements were conducted. Gas-phase and particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected using filter cassettes and XAD-2 sorbent tubes, respectively. Results showed that, under identical RH conditions, both C_total-PAHs and EF_total-PAHs followed the trend of 0.5 ACH > 2.0 ACH > 1.0 ACH, whereas total-Bap_eq and EF_Total-BaPeq values decreased with increasing ACH. While under identical ACH conditions, emissions showed a nonlinear response to RH, following the trend: 75% > 90% > 60%. Most detected PAHs were present in the gaseous phase and were dominated by low-molecular-weight compounds containing two to three aromatic rings. The estimated highest incremental lifetime lung cancer risk reached 1.20 × 10⁻⁶ for aromatherapy workers, assuming an exposure duration of 8 h day⁻¹ over 40 years. These findings highlight the potential health risks associated with the use of scented candles and emphasize the importance of adequate ventilation to reduce long-term indoor exposure. Full article

The Yasuní National Park in Ecuador’s Amazon, one of Earth’s most biodiverse regions, faces unprecedented threats from oil extraction and increasing risks to Kichwa communities. This paper provides a baseline analysis of off-the-grid hydrocarbon extraction affecting ecosystems and communities living within Oil Blocks 12 and 43. Our aim is to integrate analysis of per- and polyfluoroalkyl substances (PFAS) and total petroleum hydrocarbons (TPH) to better understand the impacts of oil-extractive contamination at off-the-grid sites in sensitive Amazonian ecosystems. To achieve that, we center the Yasuní Park and Kichwa communities as a case study. Despite Kichwa environmental concerns about contamination, conventional total hydrocarbon testing has failed to detect elevated levels due to hydrocarbon degradation, necessitating testing for other contaminants associated with extractive activities, such as PFAS, a forever chemical commonly used in drilling fluids, and other contaminants from petroleum transportation via pipelines. This research was conducted at the request of and with the participation of Kichwa residents, who needed to understand the nature of contaminants in their environment. Two participatory mapping exercises were conducted in Oil Block 12 to pinpoint 16 sampling locations, given the block’s long history of contamination. In Oil Block 43, where extraction is more recent, we sampled 5 sites where community members had observed contamination in the last year. TPH and PFAS analyses were performed using EPA methods 1633 and 1664. Results revealed 7 PFAS compounds across Oil Blocks, 11 TPH compounds in Oil Block 12, and overlap between TPH and PFAS at 6 sampling locations. Contamination was detected near community housing, food gardens, and swamped forest, which is concerning because communities rely on traditional subsistence activities, including forest gathering, fishing, and gardens for survival. This is the first environmental assessment to examine the combined presence of hydrocarbons and PFAS in the Yasuní Park and the Ecuadorian Amazon, providing communities with empirical evidence of environmental contamination. Full article

The present paper highlights a critical assessment of the large-scale production and accumulation of date palm (Phoenix dactylifera) by-products. These have been identified as both serious environmental problems and potential renewable energy sources. Landfilling, burning in fields, and other such poor methods are common among many of the countries producing dates as ways to dispose of huge amounts of date palm by-products. The current literature has been assessed for their utilization in energy generation in the form of a circular bioeconomy with respect to the characteristics and composition of date palm seeds, leaflets, rachis and fibers. The study reveals that thermochemical conversion methods such as pyrolysis, gasification and hydrothermal processes are very efficient for the conversion of date palm residues into bio-oil, syngas and biochar. The resulting bio-oils are, however, rich in oxygen, acidic and unstable in nature and need to be upgraded using a catalytic process. Moreover, the review highlights that advanced catalytic technologies can greatly improve the quality of fuel through deoxygenation and the synthesis of hydrocarbons, resulting in the production of “drop-in” gasoline components and SAFs that have characteristics close to those of regular petroleum-based fuels. Also, artificial intelligence- and machine learning-based modeling techniques appear to offer considerable prospects in the realm of thermokinetic studies, process design, and large-scale implementation. Furthermore, the results point out two environmental advantages that accrue from the date palm valorization process, since biochar generated via thermochemical transformation can be used for seawater desalination. Lastly, the techno-economic evaluation and roadmap of future development directions are provided. Full article

Deep lacustrine rift basins present persistent challenges in hydrocarbon provenance determination, charging-history reconstruction, and migration pathway prediction within heterogeneous deep reservoirs. This study applies an integrated approach combining biomarker and light-hydrocarbon geochemistry, fluid-inclusion microthermometry, and two-dimensional migration modelling to the deep Eocene Dainan Formation in the southeastern Gaoyou Sag, Subei Basin. Based on 20 analytical entries from Dainan oils/reservoir samples and Funing Formation source-rock extracts, the results indicate mixed contributions from the E₁f₂ and E₁f₄ source intervals rather than a single-source origin. Maturity parameters place most oils within the early- to main-oil window, while hydrocarbon inclusions with dominantly blue fluorescence and homogenization temperatures of 85–110 °C are consistent with a dominant Sanduo-period charging episode. Integrated migration modelling identifies two accumulation styles: a northern fault-slope migration system and a southern Zhenwu fault-conduit system, with effective accumulation favoured by the coupling of active faults and connected sand bodies. The established genetic model offers a transferable framework for derisking exploration in analogous deep lacustrine rift basins. Full article

The Tajik Basin is located on the eastern edge of the Central Asian segment of the Tethyan tectonic domain. The basin underwent intense tectonic transformation during the Himalayan period, resulting in complex structural styles, unclear original sedimentary characteristics and oil and gas geological conditions, and a complex process of oil and gas accumulation, which restricts the further evaluation of the basin’s exploration potential. Studying the Tajik Basin in the macro background of the Tethys tectonic domain, the tectonic sedimentary evolution of the Tethys tectonic domain has a significant effect on the basin’s tectonic evolution, sedimentary characteristics, and oil and gas accumulation conditions. The Tajik Basin has gone through four stages of tectonic evolution: the Late Permian to Triassic was the stage of back arc foreland basin; the Jurassic period was the stage of back arc extensional faulting depression; the Cretaceous–Paleogene period was the stage of depression basins; and the Neogene is the stage of the regenerated foreland basins. Through field geological surveys and analysis of outcrop samples, it has been determined that the Tajik Basin has developed three sets of source rocks: the Middle and Lower Jurassic, Cretaceous, and Paleogene. Among them, the organic matter abundance of the Middle and Lower Jurassic is relatively high, most of them are in the mature stage, and they are primarily gas-generating source rocks. The Cretaceous and Paleogene source rocks are mainly oil generating and in a low-mature state. There are four sets of reservoirs developed in the Tajik Basin: Middle-Upper Jurassic carbonate rocks, Lower Cretaceous clastic rocks, Upper Cretaceous carbonate rocks and Paleogene carbonate rocks. Comprehensive research shows that the Tajik Basin mainly develops three types of oil and gas reservoirs: Jurassic carbonate gas reservoirs, distributed in the southwestern Gissar Uplift and Surhan Depression in the western part of the basin; Paleogene carbonate reservoirs, distributed in the southern Vakhsh Depression and the eastern Kuliabu Depression; and multi layer–multi lithology oil and gas reservoirs, distributed in the northern Dushanbe Depression. The primary controlling factor for the three types of oil and gas reservoirs is tectonic movement, which forms traps and simultaneously reshapes the reservoirs, ultimately leading to effective accumulation of oil and gas. The distribution of oil and gas in the Tajik Basin is characterized by “west gas and east oil, west more and east less, west pre-salt and east post-salt, and pre-salt gas and post-salt oil”. Affected by the regional tectonic movements of the Tethys rich oil and gas tectonic domain, the basin has high-quality hydrocarbon source rocks, reservoirs, and cap rock conditions. The pre-salt Jurassic has the potential to form large natural gas reservoirs, while the post-salt Cretaceous and Paleogene still have further potential for exploration. Full article

Utilizing seawater samples collected during the summer of 2025 in the Dingzi Bay region, South Yellow Sea, this study conducted a comprehensive analysis of the contents and concentrations of dissolved gases (N₂, O₂, Ar, CO₂) and hydrocarbon gases (such as methane, ethane, and propane). The findings reveal that the dissolved gases in the study area are predominantly composed of N₂ and O₂, with average proportions of 77.8% and 21.6%, respectively. Notably, significant CO₂ anomalies were detected at certain stations, which may indicate intense organic matter degradation or the introduction of external fluids. Furthermore, wet gas constituents, including propane, butane, and isobutane, were identified in several samples, suggesting potential submarine oil and gas seepage or subsurface thermogenic gas input. Spatial analysis revealed that anomalous points were primarily concentrated at stations CJ01, CJ08, CJ10, and CQ01, with no significant correlation to water depth, suggesting that their distribution may be influenced by local geological structures or bottom currents. This study elucidates the complexity and heterogeneity of dissolved gas composition in the waters of Dingzi Bay, thereby providing a novel scientific foundation for regional carbon cycle research, seabed resource exploration, and marine environmental monitoring. Full article

Petroleum exploitation in the Niger Delta has caused widespread contamination of mangrove ecosystems, yet studies that integrate total petroleum hydrocarbons (TPH) and metals in mangrove water are still very limited. This study presents the first dual-pollutant baseline assessment of TPH and five priority metals (Cd, Cr, Pb, Ni, Zn) in Bille mangrove water, a severely oil-impacted system supporting about 50,000 residents. Water samples were collected from six sites along a contamination gradient (flow station, pipeline passage, old bunkering site) and analyzed for TPH (C8–C40) and metals. All concentrations are reported in mg/L for direct comparability with World Health Organization (WHO) drinking-water guidelines and United States Environmental Protection Agency (USEPA) thresholds. TPH concentrations ranged from 0.18 to 57.66 mg/L, with Site 3 (pipeline passage) showing levels about 320-fold higher than reference sites and exceeding the WHO drinking-water guideline (0.05 mg/L) by up to 1153-fold. Cadmium (0.040–0.350 mg/L) and nickel (0.055–0.561 mg/L) exceeded WHO drinking-water guidelines (Cd 0.003 mg/L; Ni 0.07 mg/L) by 13–117- and up to 8-fold, respectively. Health risk assessment, using USEPA Risk Assessment Guidance for Superfund (RAGS) protocols, revealed a total cancer risk of 4.15 × 10⁻³ at Site 3, 41-fold above the USEPA acceptable threshold of 1 × 10⁻⁴, and extreme non-carcinogenic risk (Hazard Index = 20.03–25.51) at petroleum-infrastructure sites; cadmium contributed 86–88% of both carcinogenic and non-carcinogenic effects. Ecological risk indices classified Site 3 as extreme (Potential Ecological Risk Index = 722, against the Håkanson PERI = 600 “very-high-risk” threshold), mainly driven by cadmium (Er = 310–350) and nickel (Er = 140–150). Source apportionment using the Carbon Preference Index, enrichment factors, and strong TPH–metal correlations (r > 0.88, p < 0.01) clearly identified petroleum operations as the dominant contamination source. This work demonstrates the critical importance of integrated multi-pollutant assessments in petroleum-degraded mangrove water for guiding environmental protection and public-health interventions. Full article

The Permian Taiyuan and Shanxi Formations of the Upper Paleozoic in the Ordos Basin are the primary source rock sequences for tight sandstone gas. The core problem lies in the uncertainty surrounding the gas generation process at the overmature stage. To clarify hydrocarbon generation processes and the potential of coal, carbonaceous mudstone and dark mudstone, we integrate basin modeling and hydrocarbon generation pyrolysis thermal simulation experiments. Using PetroMod software and measured well data on vitrinite reflectance (Ro), total organic carbon (TOC), T_max and hydrocarbon generation potential (S₁ + S₂), we quantitatively reconstruct the burial, thermal, maturity and hydrocarbon evolution histories of the southern Ordos Basin. The results indicate that the main oil generation window is concentrated at 400 °C, and gas yield increases continuously from 350 °C to 700 °C without a peak, showing that coal and carbonaceous mudstone still have considerable hydrocarbon generation potential under extreme high-temperature conditions. Combining the hydrocarbon generation ratio, rock density and TOC data, coal is identified as the predominant source rock in the southern Ordos Basin. This study provides a scientific basis for tight gas exploration in cratonic basins, enhances the understanding of gas generation in coal-bearing source rocks, and offers a new perspective for oil and gas resource evaluation. Full article

Deep unconventional oil and gas reservoirs are critical to hydrocarbon exploration and development in China. However, their complex geological and petrophysical features, including high temperature, high pressure, high salinity, multiple pressure systems, and intricate pore–fracture structures, make them highly susceptible to formation damage during drilling, completion, stimulation, and production. Effective reservoir protection is therefore essential for minimizing damage and improving development efficiency. This paper systematically reviews recent advances in reservoir protection for deep unconventional reservoirs, with a focus on evaluation methods and protective materials. Laboratory evaluation methods, including permeability recovery, nuclear magnetic resonance, pressure decay, and spontaneous imbibition, together with field-based approaches such as well testing and production decline analysis, are summarized and assessed for their applicability to complex damage characterization. Major damage mechanisms, including liquid-phase trapping, solid invasion, sensitivity damage, stress sensitivity, and wettability alteration, are analyzed with emphasis on working fluid–reservoir interactions under multi-field coupling conditions. Recent progress in protective materials is also reviewed, covering polymer-based materials such as gel sealing agents, delayed-swelling hydrogels, water-/oil-soluble temporary plugging agents, and film-forming polymers, as well as ultrafine CaCO₃ and fiber-based materials. In addition, related protection technologies, including temporary plugging, film-forming fluid-loss control, underbalanced drilling, and low-damage completion fluids, are discussed. Existing models developed for conventional sandstone reservoirs are insufficient for deep unconventional systems. Future research should prioritize integrated evaluation and protection methods tailored to deep tight, shale, and fractured–vuggy carbonate reservoirs. This review provides a basis for understanding complex damage mechanisms, developing functional protective materials, and advancing integrated reservoir protection technologies for the efficient development of deep unconventional resources. Full article