Oil Hydrocarbons Research Articles

Enhanced Remediation of Polycyclic Aromatic Hydrocarbons in Soil Through Fungal Delignification Strategy and Organic Waste Amendment: A Review

AbstractNutrient-limited soils from growing global contamination with polycyclic aromatic hydrocarbons (PAHs) and the massive organic waste generation from agro-based and food industries have raised more demand for exploring and recycling the latter as sustainable, cost-effective, and green nutrient-rich sources for soil amendment. To further enhanced the potentials of these substrates in soil, immobilisation or biological pre-treatment techniques using fungi are employed. The white-rot fungi- basidiomycetes, are the most widely researched and efficient organisms to perform these functions because of their high lignin-degrading ability for organic materials, such as corn cob, straws, spent brewery grains, sugarcane bagasse, etc. This review addresses the importance of organic amendment to enhance the biodegradation efficiency of PAH from contaminated soils and it also highlights various biological techniques for improving PAH biodegradation using organic waste materials and white-rot basidiomycetes. This review will also show a better understanding of the concepts of fungal immobilisation and pre-treatment for PAH degradation in soil and show their insights as feasible and optimise techniques for developing remedial strategies for contaminated soils.

Naphthalene Enhances Polycyclic Aromatic Hydrocarbon Biodegradation by Pseudomonas aeruginosa in Soil and Water: Effect and Mechanism

Bioremediation is a promising technique owing to its effectiveness, low cost, and environmental friendliness. Previous studies have focused on the degradation efficiency of polycyclic aromatic hydrocarbons (PAHs) in soil and water. However, the expression of PAH-catabolic genes in organisms involved in the degradation process has been rarely and unsystematically reported. In this study, a PAH-degrading strain—Pseudomonas aeruginosa (PQ249631)—was successfully isolated from coking-contaminated soil and used for PAH degradation in soil and water. Furthermore, the degradation of PAHs (naphthalene, fluorene, phenanthrene, anthracene, and pyrene) was investigated in single, binary, and mixture systems to explore the interaction of substrates. The results showed that when naphthalene was used as a cometabolite carbon source, the removal rates of fluorene, phenanthrene, anthracene, and pyrene increased from 14.33%, 17.25%, 6.61%, and 4.47% to 72.08%, 100.00%, 15.63%, and 6.63%, respectively. In a PAH mixture, the degradation rate of each PAH was higher when naphthalene, rather than glucose, was used as the cometabolite carbon source. Transcriptome analysis revealed significant differential expression of PAH-catabolic genes and ATP-binding cassette transporter-related genes under naphthalene stress. The enhanced degradation of PAHs could be attributed to the augmentation of the PAH metabolic pathway and membrane transportation, facilitating the transfer of PAHs to bacteria. These findings underscore the effectiveness of P. aeruginosa as a PAH degrader and provide molecular insights into enhancing PAH degradation.

Surfactant-Based Chemical Washing to Remediate Oil-Contaminated Soil: The State of Knowledge.

As the energy demand increases, there is a significant expansion and utilization of oil resources, resulting in the inevitable occurrence of environmental pollution. Oil has been identified as a prevalent soil contaminant, posing substantial risks to the soil ecosystems. The remediation of soil contaminated with oil is a formidable undertaking. Increasing evidence shows that chemical washing, a remediation technique employing chemical reagents like surfactants to augment the solubilization, desorption, and separation of petroleum hydrocarbons in soil, proves to be an efficacious approach, but the latest advances on this topic have not been systematically reviewed. Here, we present the state of knowledge about the surfactant-based chemical washing to remediate oil-contaminated soil. Using the latest data, the present article systematically summarizes the advancements on ex situ chemical washing of oil pollution and provides a concise summary of the underlying principles. The use of various surfactants in chemical washing and the factors influencing remediation efficiency are highlighted. Based on the current research status and knowledge gaps, future perspectives are proposed to facilitate chemical washing of oil-polluted soil. This review can help recognize the application of chemical washing in the remediation of oil-polluted soil.

Distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons in surface soils and plants from industrial and agricultural areas, Junggar Basin, Xinjiang

The contamination characteristics of Polycyclic Aromatic Hydrocarbons (PAHs) in different environmental functional areas are different. In this study, the contamination of PAHs in soils and common plants in typical mining and farmland areas in Xinjiang, China, was analyzed. The results showed that the contamination levels of PAHs in mining soils were significantly higher than those in farmland soils, and the mining soils were dominated by 4-5-ring PAHs and farmland soils by 3-4-ring PAHs. Analysis of their sources using a positive definite factor matrix model showed that PAHs in mining soils mainly originated from coal and natural gas combustion, and transportation processes; while farmland soils mainly came from biomass and coal combustion, and fossil fuel volatile spills. The cancer risk of PAHs in soils was evaluated using a combination of the Monte Carlo and the lifetime carcinogenic risk models, and the results showed that the overall level of cancer risk for mining soils was higher than that for farmland soils, and can put some people in high risk of cancer. For plant samples, except for individual crop samples, the contamination levels of mining plants and crops were similar, with 4-5-ring PAHs dominating in desert plants in mining areas and the highest proportion of 3-ring PAHs in crops in agricultural fields, and PAHs in both plants were mainly from biomass and coal combustion. The results of correlation analysis showed that 2-ring PAHs in crop roots were significantly positively correlated with it in corresponding soils, and some high-ring PAHs in crop leaves were significantly negatively correlated with it in corresponding soils. Therefore, there were significant differences in the pollution characteristics of PAHs in soils and common plants in mining and agricultural areas. Human health risks and ecological risks are mainly concentrated in mining areas, and appropriate intervention measures should be taken for pollution remediation.

Targeted preparation for hydrocarbons through catalytic hydrodeoxygenation of co-pyrolysis bio-oil using bimetal-loaded Nb2O5 catalyst

The co-pyrolysis of industrial enzymatic hydrolysis of lignin residue with waste plastic to produce bio-oil can increase resource utilization and reduce pollution. However, the high concentration of oxygenated compounds, particularly phenolic compounds, limits the large-scale application of crude bio-oil. Bimetallic-loaded bifunctional catalysts have been prepared by loading different transition metals and Ru onto Nb2O5. We explored their performances in crude co-pyrolysis bio-oil hydrodeoxygenation (HDO). Compared to other transition metals, the selectivities for aromatic hydrocarbons, phenolic compounds, and other oxygenated compounds in the upgraded oil obtained by the catalytic HDO of Ni and Ru bimetallic-loaded Nb2O5 (Ni-Ru@Nb2O5) was the lowest, whereas the aliphatic hydrocarbons selectivity was the highest. The selectivities for other oxygenated compounds, phenolic compounds, and aromatic hydrocarbons in the upgraded oil decreased as the Ni loading increased, whereas the aliphatic hydrocarbons selectivity increased. Ni-Ru@Nb2O5 catalyzed HDO of crude bio-oil showed a maximum selectivity of 86.30 % for hydrocarbons in the upgraded oil at a reaction time of 2 h and a reaction temperature of 280 °C. The degree of deoxygenation of upgraded oil reached 68.87 % under optimal conditions, and the molar ratio of H-to-C was increased from 1.31 (crude bio-oil) to 2.37 (upgraded oil). Ni-Ru@Nb2O5 is an effective catalyst method for the HDO of crude bio-oil.

Calm Before the Storm?

Atlantic hurricane season poses an annual threat to the billions of dollars of oil and gas hardware pumping hydrocarbons from the depths of the US Gulf of Mexico (GOM). The region’s offshore production amounts to about 1.8 million B/D—roughly 14% of the total crude output in the US, according to the US Energy Information Administration, so any disruption is felt by oil markets across the globe. Prior to the 2024 hurricane season, forecasters pegged this year as primed to be particularly intense. Colorado State University (CSU), known for its storm prognostication, estimated that the basin would experience 23 named storms, with a dozen of those becoming hurricanes (winds of 74 mph or higher), and six of those strengthening to major hurricanes (winds of 111 mph or higher). Similarly, AccuWeather meteorologists expect between 20 and 25 named storms with a possibility of 30 or more. As the season enters its busy period, the basin has only experienced five named storms to date; however, many forecasters are sticking to their initial forecasts and continue to warn of an intense September/October period. “The months of September and October should be very active across the Atlantic,” said AccuWeather lead hurricane expert Alex DaSilva. “We continue to remain very concerned about rapid intensification. Sea-surface temperatures and ocean heat content are near record levels across most of the Atlantic basin. This can act like jet fuel for tropical systems. We also continue to believe that La Niña will emerge sometime in November. When water temperatures near the equator of the eastern Pacific Ocean are lower than the long-term historical averages for an extended period, La Niña is declared. Although this is a phenomenon in the Pacific, it has ramifications for weather patterns over the Atlantic Ocean. Specifically, La Niña can reduce the wind shear across the basin. When wind shear is lower, it makes it easier for tropical systems to take shape and strengthen.” The GOM has experienced one disruption in 2024 courtesy of Hurricane Beryl. Once a Category 5 storm (winds 155 mph and higher)—and the earliest-forming Category 5 storm on record—Beryl weakened as it crossed the southern Yucatán. The storm regained Category 1 strength as it crossed the far western offshore oil patch enroute to landfall near Matagorda Bay, Texas. Shell shut in production at its Perdido spar because of the storm as well as evacuated personnel from it and its Whale facility. Chevron moved all non-essential personnel off its Anchor floating production unit, which was undergoing commissioning at the time. The last major storm to cut a path straight through the heart of the US offshore oil patch was 2021’s Hurricane Ida. Ida tore through the region as a Category 4 storm before slamming into the Louisiana coast near Port Fourchon packing 150 mph winds on 29 August. The storm prompted the shut in of almost 100% of the Gulf’s oil and gas production and caused extensive damage to major hubs in the region, including the Shell-operated West Delta Block 143 complex. The facilities, which serve as the transfer station for production from Shell’s robust Mars corridor, were off line for several months.

A Petrophysical Properties Evaluation Study of a Niger Delta Field Using Well Logs and Core Data

A petrophysical properties evaluation study of an onshore field “NEMA” was carried out to assess the petrophysical characteristics of the field in the eastern portion of the Niger Delta Basin. This was done in an effort to determine the hydrocarbon prospect and oil productivity potential of the reservoirs. The net/gross thickness was one of the examined parameters. (pay zone thickness), porosity, permeability, fluid saturation which were all inferred from geophysical wireline logs and core data. The wireline logs used in the investigation included density, resistivity, gamma ray, and spontaneous potential logs for five different wells from the “NEMA” oil field. Five reservoirs designated, NEMA 01, NEMA 04, NEMA 07, NEMA 09, and NEMA 12 were identified and correlated across the five wells in the field using gamma ray logs and shale resistivity markers. Based on the computation of petrophysical parameters, the porosity of the reservoirs ranged from 0.22 (22%) to 0.31 (31%); the permeability ranged from 851.58 mD to 1005.05 mD; the average net-to-gross thickness of the reservoir sand bodies was 140 ft; the water saturation value was less than 45%, while the hydrocarbon saturation was greater than 55%. We equally observed that our computed petrophysical parameters from well log data correlated well with the core computed values in NEMA 09. In conclusion, the delineated reservoirs were categorized as good hydrocarbon reservoirs. These results suggest huge hydrocarbon potential and a reservoir system whose performance is considered satisfactory for hydrocarbon production.

Investigation of process parameters for modeling of ceramic composite SiSiC IN dry EDM (DEDM) cutting

The manufacturing industry is currently grappling with issues related to energy dissipation and product quality, both of which significantly impact productivity. In addressing this pertinent concern, this study endeavours to identify the key indicators that contribute a crucial role in machining process. The Dry EDM (DEDM) emerges as a novel technology, wherein environmentally friendly gases serve as an alternative dielectric medium instead of liquid EDM approaches. In conventional EDM process, hydrocarbon oils release toxic emissions while the gases used in Dry EDM process don’t produce harmful emissions and hence make the DEDM process sustainable.An investigation has been carried out to observe the influence of different gases like O2, N2 and Air on Siliconized Silicon-Carbide plate (SiSiC) of ø50mm*2 mm under Dry Electrical Discharge Machining. Effect of different tools is also observed using varying shapes of electrodes like plane Cu electrode of ø6 mm diameter with 60 mm length and tubular shape with outer diameter ø6mm and inner diameter ø5.1 mm with a length of 60 mm. The three gases are one by one supplied through a nozzle in the presence of plane Cu electrode to make the holes in SiSiC plate. The same process is executed with tubular Cu electrode. Modified Taguchi Orthogonal Array is applied to analyze the effect of control factors such as gap voltage, discharge current and pulse on-time through a series of experiments. Effect of different shape of tools and different gases is observed for the material removal rate (MRR) and surface roughness (SR) of specimen.In this paper, a latest DEDM process of swirl assisted flushing is proposed which provides a new technique to solve the problems of low MRR and poor surface integrity. Swirl assisted flushing works on Decay Law and also microscopic investigation justifies its validity. It is concluded by this research that current and Pulse on time are more contributing factors about 53.3 % and 27 % respectively. Furthermore, it is noted that DEDM increases MRR 19.5 % and lowers Ra approximately 2/3 than traditional machining. The MRR of O2 is about 3.1 times more than Air and N2 comes at least position while N2 creates better quality of surface due to formation of an inert nitride layer. Empirical relations are established for SR and MRR using Minitab 18 Software to develop a robust model. Confirmation test is performed to check the validity of developed mathematical model. The Novelty of this research is also extended by introducing a new method SAF. The results are finally evaluated by ANOVA.

Molecular identification of rhamnolipids produced by Pseudomonas oryzihabitans during biodegradation of crude oil.

The ability to produce biosurfactants plays a meaningful role in the bioavailability of crude oil hydrocarbons and the bioremediation efficiency of crude oil-degrading bacteria. This study aimed to characterize the produced biosurfactants by Pseudomonas oryzihabitans during the biodegradation of crude oil hydrocarbons. The biosurfactants were isolated and then characterized by Fourier transform infrared (FTIR), liquid chromatography-mass-spectrometry (LC-MS), and nuclear magnetic resonance spectroscopy (NMR) analyses. The FTIR results revealed the existence of hydroxyl, carboxyl, and methoxyl groups in the isolated biosurfactants. Also, the LC-MS analysis demonstrated a main di-rhamnolipid (l-rhamnopyranosyll-rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate, Rha-Rha-C10-C10) along with a mono-rhamnolipid (l-rhamnopyranosyl-b-hydroxydecanoylb-hydroxydecanoate, Rha-C10-C10). In agreement with these findings, the NMR analysis confirmed the aromatic, carboxylic, methyl, sulfate moieties, and hexose sugar in the biosurfactants. The emulsion capacity of the biosurfactants decreased the surface tension of the aqueous system from 73.4 mN m-1 to around 33 mN m-1 at 200 mg L-1 as the critical micelle concentration. The emulsification capacity of the biosurfactants in the formation of a stable microemulsion for the diesel-water system at a wide range of pH (2-12), temperature (0-80°C), and salinity (2-20 g L-1 of NaCl) showed their potential use in oil recovery and bioremediation through the use of microbial enhancement. This work showed the ability of Pseudomonas oryzihabitans NC392 cells to produce rhamnolipid molecules during the biodegradation process of crude oil hydrocarbons. These biosurfactants have potential in bioremediation studies as eco-friendly and biodegradable products, and their stability makes them optimal for areas with extreme conditions.

Optimization of product distribution during co-pyrolysis of furfural residues and waste tyres via response surface method and infrared heating

Co-pyrolysis technique has proved to be an available way to recycle the energy of biomass waste and improve bio-oil quality. In this work, the co-pyrolysis behaviors and product distribution of waste tyres (WT) and furfural residues (FR) were studied by TG-FTIR/GC–MS and infrared heating fixed reactor. TG-FTIR/GC–MS results show that a large amount of CH4 and aromatics were produced at the co-pyrolysis temperature of 410°C. The response surface methodology (RSM) was utilized to optimize the yields of co-pyrolysis products, including oil, aromatic hydrocarbon (AH) in oil, and CH4 in gas. It was found that the highest oil production of 39.24 wt% was obtained at 550 °C and 10 °C/s, with the highest AH content of 35.02 % and the highest CH4 yield of 17.65 wt% at 700 °C and 40 °C/s. Co-pyrolysis oil and char characteristics were analyzed by SIMDIS, GC–MS, XPS, and the ultimate analysis. It was found that there was a high D-limonene content in oil (up to 25.79 %). With increasing co-pyrolysis temperature, AH content gradually increased and that of acid in oil declined. As the temperature elevated from 400 to 700 °C at 10 °C/s, the content of AH rose from 6.48 to 31.56 % and that of acid decreased from 19.74 to 11.73 %. In addition, the transformation of organic sulfur into metal sulfides was facilitated by raising the temperature.

β-Cyclodextrin enhanced bioavailability of petroleum hydrocarbons in industrially contaminated soil: A phytoremediation field study

Low remediation efficiency due to low bioavailability is a primary restrictive factor for phytoremediation applications. Specifically, this investigation examines whether Suaeda heteroptera Kitagawa (S. heteroptera) can be used in combination with β-cyclodextrin (β-CD) to remediate contaminated site. The study was conducted on the growth response of S. heteroptera, bioavailability and dissipation of petroleum hydrocarbons (PHs) in soil under the influence of β-CD Our preliminary studies confirmed that β-CD is effective in increasing the biomass and height of plants. The presence of β-CD could dramatically elevate polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in S. heteroptera. Moreover, a remarkable positive correlation between PHs levels in roots with the dosage of β-CD and a negative correlation between the PHs levels in roots with KOW of PHs have been observed. The dissipation of n-alkanes was estimated to be 38.73–62.27%, and the dissipation of PAHs was 36.59–60.10%. In addition, the dissipation behavior of n-alkanes and PAHs was well agreement with the first-order kinetic model. These results display that applying β-CD accelerated the desorption process of PHs from soil and promoted the absorption process of PHs onto the root epidermis. The enhancement of phytoremediation was achieved by increasing the bioavailability of PHs.

Screening of Active Oil Destructors from Various Zones of Urban Soils (on the Example of Baku)

Active cultures of hydrocarbon-decomposing microorganisms from soils of various functional zones of Baku were screened. It was shown that 15 cultures of hydrocarbon-decomposing microorganisms isolated as a result of continuous screening belonged to the genera Rhodococcus, Pseudomonas, Bacillus, Mycobacterium, Actinomyces, Arthrobacter, Micrococcus and were able to use various hydrocarbons (crude oil, paraffin and aromatic hydrocarbons and petroleum products) as the only source of carbon and energy. According to the degree of decomposition, petroleum hydrocarbons were ranked in the series: a mixture of paraffins petroleum products aromatic hydrocarbons crude oil, while the most active strains of microorganisms were isolated from the soils of the industrial and transport zones of Baku, compared with the soils of the recreational zone. The isolated active strains can be considered promising for the creation of biological products to increase soil resistance to pollutants and activate the processes of self-purification of already contaminated soils.

Nitrogen utilization efficiency assessment during bioremediation of petroleum-contaminated loess soils: insights from metagenomic analysis

Nitrogen addition is commonly used to remediate total petroleum hydrocarbons (TPH) in petroleum-contaminated soils. However, acceptable exogenous nitrogen dosages and their utilization efficiency for the degradation of hydrocarbons in oil-polluted soils are not well understood. This study compared the hydrocarbon bioremediation capacity by applying different doses of NH4Cl as a stimulant in soils contaminated with TPH at 8553 and 17090 mg/kg. The results showed acceptable exogenous nitrogen levels ranging from 60 to 360 mg N/kg soil, and the optimal nitrogen dosage for TPH remediation was 136 mg N/kg in soils with different TPH concentrations. The nitrogen availability efficiency (NAE) and nitrogen polarization factor availability (NPFA) in the 136 mg N/kg addition treatments were 6.69 and 20.47 mg/mg in 8533 mg/kg TPH-polluted soil, and 6.03 and 31.11 mg/mg in 17090 mg/kg TPH-polluted soil, respectively. Metagenomic analysis revealed that the application of 136 mg/kg nitrogen facilitated ammonia oxidation and nitrite reduction to nitric oxide, and induced soil microorganisms to undergo regulatory or adaptive changes in energy supply and metabolic state, which could aid in restoring the ecological functions of petroleum-contaminated soils. These findings underscore that 136 mg/kg of nitrogen dosage application is optimal for remediation of petroleum-contaminated soils irrespective of the TPH concentrations. This exogenous nitrogen application dosage for TPH remediation aligns with the nitrogen requirements for crop growth in agriculture.

Compositional change of bacterial communities in oil-polluted seawater amid varying degrees of nanoplankton bacterivory

Petroleum hydrocarbons are being released into the marine environment continuously. They will undergo weathering and may eventually be biodegraded by bacteria and other microbes. While nanoplankton (2–20 μm) are the major consumers of marine bacteria, their effect on the process of biodegradation of oil hydrocarbons is still debated. A 14-day microcosm experiment was conducted to investigate the effects of crude oil hydrocarbons on nanoplankton bacterivory and bacterial community in coastal waters. The coefficients of population growth (0.56–1.80 d−1 for all treatments considered) and grazing mortality (0.38–1.65 d−1 for all treatment considered) of bacteria estimated with the dilution method did not differ among the treatments of control (Ctrl), low dose chemically dispersed oil (LDOil, 2 μL L−1 of crude oil), and high dose chemically dispersed oil (HDOil, 8 μL L−1 of crude oil). Bacterial abundance ranged between 0.21–0.86 × 106 cells mL−1 on average for all treatments. The lack of drastic increases in the cell density of bacterial cells in the oil-loaded treatments was observed throughout the experiment period. Sequencing analysis of the 16S rRNA gene revealed the progressive changes in the community compositions of bacteria in all treatments. The relatively high abundance of oil-degrading bacteria, including Cycloclasticus and Alcanivorax on Days 3–14 of the experiment reflected the presence of biodegradation of oil in the LDOil and HDOil treatments. Throughout the 14 days, the community composition of bacteria in the LDOil and HDOil treatments became more similar and they both differed from that in the Ctrl treatment. This study concluded that, in oil-polluted seawater, the changes in the bacterial community composition were mainly resulting from the addition of chemically dispersed crude oil.

STRUCTURE AND FORMATION OF MUD VOLCANOES IN THE SOUTH CASPIAN BASIN ACCORDING TO SEISMIC DATA

The South Caspian Basin (SCB) constitutes a classic province to study mud volcanoes and their associated processes. About 280 active mud volcanoes have been documented in the offshore and the onshore areas of Azerbaijan, emitting water, hydrocarbons (oil and mainly methane), and fluidized muds that transport solid fragments from deep sedimentary sequences. Seismic characteristics of mud volcano systems in the Azerbaijan area of the SCB are used to address: (1) the nature of the mud volcano source layer, (2) the internal geometry of the feeder systems, and (3) the processes associated with shale mobilization and extrusion. We confirm that the source layer is mainly the Maykop Suite (Oligocene–Lower Miocene), which is a thick (up to 3 km) and deep (>10 km) clayey sequence rich in organic matter. This layer was quickly buried due to basin subsidence and the rapid deposition (since the Middle Miocene) of thick fluvio-lacustrine sediments of the Productive Series (Upper Miocene–Upper Pliocene), which contributed to the creation of high pore pressures and the transformation of organic matter into methane (through thermal cracking). Since the Middle Miocene, and more importantly during the Upper Pliocene, the Maykop shales mobilized due to an increase in shear stresses and pore pressures, which promoted a decrease in effective stresses and, as a consequence, facilitated the achievement of critical state conditions in the shales that began to flow. This process repeated over time, allowed multiple pulses of shale mobilization to originate (as in a loading piston system). Shale piercing transporting deep-sourced fluids (and hydrocarbons) was carried out through fractures in the outer arc of anticlines, forming subvertical feeder systems. The mobilized hydrocarbons and fluids also recharged some of the younger and more permeable layers of the Productive Series, creating shallower reservoirs in the vicinities of the mud volcano structures.

Bioremediation of Polyaromatic Hydrocarbons in Soils: A Review of Recent Progress

Bioremediation of Polyaromatic Hydrocarbons in Soils: A Review of Recent Progress

“Component flow” conditions and its effects on enhancing production of continental medium-to-high maturity shale oil

Based on the production curves, changes in hydrocarbon composition and quantities over time, and production systems from key trial production wells in lacustrine shale oil areas in China, fine fraction cutting experiments and molecular dynamics numerical simulations were conducted to investigate the effects of changes in shale oil composition on macroscopic fluidity. The concept of “component flow” for shale oil was proposed, and the formation mechanism and conditions of component flow were discussed. The research reveals findings in four aspects. First, a miscible state of light, medium and heavy hydrocarbons form within micropores/nanopores of underground shale according to similarity and intermiscibility principles, which make components with poor fluidity suspended as molecular aggregates in light and medium hydrocarbon solvents, such as heavy hydrocarbons, thereby decreasing shale oil viscosity and enhancing fluidity and outflows. Second, small-molecule aromatic hydrocarbons act as carriers for component flow, and the higher the content of gaseous and light hydrocarbons, the more conducive it is to inhibit the formation of larger aggregates of heavy components such as resin and asphalt, thus increasing their plastic deformation ability and bringing about better component flow efficiency. Third, higher formation temperatures reduce the viscosity of heavy hydrocarbon components, such as wax, thereby improving their fluidity. Fourth, preservation conditions, formation energy, and production system play important roles in controlling the content of light hydrocarbon components, outflow rate, and forming stable “component flow”, which are crucial factors for the optimal compatibility and maximum flow rate of multi-component hydrocarbons in shale oil. The component flow of underground shale oil is significant for improving single-well production and the cumulative ultimate recovery of shale oil.

Solid bitumen Rhenium-Osmium (Re–Os) isotope geochronology and existing problems: Sampled of Sinian-Cambrian gas reservoir in Sichuan Basin, China

Understanding the key timings related to petroleum evolution is crucial for optimizing exploration targets and assessing oil/gas resources, attract petroleum geologists’ attention worldwide. Recently, hydrocarbon (oil and bitumen) Re–Os isotope dating has been innovatively applied to constrain the timing related to oil/gas generation, however, the resulting Re–Os isochron ages can be complex and challenging to interpret. This study utilizes various geochemical and geochronological data from Sinian to Cambrian natural gas reservoirs in the Sichuan Basin to reconstruct the hydrocarbon evolution process and discuss the significance of different bitumen Re–Os dating results. The gas accumulation in the Sinian-Cambrian reservoirs experienced four stages of evolution: (1) initial oil generation during the Ordovician to Silurian periods, (2) secondary oil generation during the Triassic period, (3) gas generation through thermal cracking of liquid oil from the Jurassic to Cretaceous periods, and (4) gas reservoir redistribution since the late Cretaceous. The Re–Os dates (ca. 485 Ma) of low maturity and biodegraded bitumen from the western Sichuan Basin record the oil generation during the Ordovician before the Caledonian tectonic event. The Re–Os dates (ca.184–128 Ma) of highly mature bitumen associated with MVT Pb–Zn deposits in northern Sichuan Basin provide insights into both liquid oil-cracking and thermochemical sulfate reduction (TSR) processes. The complex Re–Os dates (ca.414 Ma, ca.154 Ma) of highly mature bitumen from the central Sichuan Basin may represent different periods related to either oil or gas generation. Future studies should explore the genetic type, maturity, thermal cracking, or TSR degrees of bitumen to better understand the significance of Re–Os dates.

The influence mechanism of water-liquid CO2 treatment on the hydrophobicity of vitrinite and inertinite

Liquid CO2 has similar properties to non-polar hydrocarbon oils and can be used to achieve hydrophobic aggregation separation of coal macerals. To reveal the influence of the water-liquid CO2 treatment on the interfacial properties of vitrinite and inertinite, the effects of the water-liquid CO2 system on the interfacial properties of vitrinite and inertinite were investigated by SEM, BET, FTIR, and XPS. The results showed that the content of oxygen-containing functional groups on the coal macerals were reduced more significant than the hydrocarbons due to the physical adsorption and chemical extraction of liquid CO2, which led to an increase in the hydrophobicity of vitrinite and inertinite. The higher porosity and specific surface area of inertinite causing the decrease in the content of oxygen-containing functional groups in inertinite was greater than that in vitrinite. This study provides theoretical support for the separation of coal macerals using liquid CO2 hydrophobic agglomerates.

Distribution, migration, and segmented risk assessment of the total petroleum hydrocarbons in soil, groundwater, and soil gas at an oil refinery

In this study, the concentrations of six petroleum hydrocarbons (n-alkane hydrocarbons (total petroleum hydrocarbons [TPH] (C6-C9) and (C10-C40)), BTEX(benzene, toluene, ethylbenzene, m & p-xylene)) in 261 soil, 31 groundwater, and 4 soil gas samples were measured to determine their spatial distribution，migration patterns and human health risks. To assess the rationality of parameter selection, GS-MS (gas chromatography-mass spectrometry) method was used to analyze the chemical composition of TPH (C6-C9), shanghai local regulation was referenced to assess TPH (C10-C40) various segmentation health risks. The results revealed that the contaminants were mainly concentrated in the refining workshop and the storage tank. The pathway of steam invasion in soil gas and the CR (carcinogenic risk) and HQ (hazard quotient) assessment of benzene in soil gas were 0–4 and 1–3 orders of magnitude higher than those in soil. TPH (C6-C9) was more similar to the Total Petroleum Hydrocarbons (Aromatic Low) in RSL (Regional Screening Level). Aliphatic hydrocarbons [AHCs]. (C10-C12) had the highest non-carcinogenic risk among all TPH (C10-C40) parts. The present study provided a reference to accurately determine the toxicological parameters of TPH (C6-C9) and TPH (C10-C40) and to improve the BTEX risk assessment methods.