Search Results (1,871)

Light oil, a high-quality energy resource abundant in deep basins, is prevalent in the northern zone of the Dongying Depression. To elucidate the formation mechanism of light oil reservoirs, this study investigates the molecular and stable isotope composition, biomarkers, light hydrocarbons, and diamondoid compositions of petroleum. The results reveal that the gas primarily consists of oil-cracking gas from a late filling event, mixed with oil-associated gas generated during the source rock’s “oil window” maturity phase. Methane exhibits enriched light carbon isotopes, indicating noticeable migration fractionation effects. The crude oil in the same deep strata exhibits high maturity, originating from both terrestrial and aquatic organic matter in the source materials. Molar proportions of n-alkanes and light hydrocarbon indices (Tol/nC₇, nC₇/MCH) indicate significant evaporative fractionation in the petroleum reservoirs. This fractionation process modified early-formed oil reservoirs due to the late filling of highly mature gas reservoirs. The evaporative fractionation at different stages has varying effects on the diamondoid ratio (1- + 2-MA)/(3- + 4-MD). It is considered a pivotal mechanism in the formation of deep condensate reservoirs and volatile oil reservoirs. Full article

Steam displacement is prone to cross-flow, small swept area, large oil–water ratio, large oil–water interfacial tension, and low oil displacement efficiency. Compared with steam flooding, foam flooding can effectively reduce the residual oil in the small throat of the main flow channel and the small hole in the near flow channel and increase the overall recovery factor. Therefore, researchers carried out CO₂ and chemical agent-assisted steam displacement. However, at present, there is a lack of research on the occurrence mechanism and model of residual oil. Steam flooding often encounters challenges such as cross-flow, limited sweep area, and high oil–water ratio. Foam flooding offers a promising alternative by effectively reducing residual oil in narrow throats and the near flow channel, thereby enhancing overall recovery rates compared to steam flooding alone. Therefore, chemical agent-assisted steam flooding was applied to enhance heavy oil recovery. However, the occurrence mechanism and model of residual oil after chemical agent-assisted steam is not clear. To fill this gap, the CO₂ foam viscosity reducer assisted steam (CFVAS) flooding technology has been adopted and carried out in several studies. First, the foam viscosity reducer was prepared and its foam properties (viscosity reduction effect, foam volume, and half-life) were tested. Subsequently, the CFVAS displacement experiments after steam flooding were carried out, and the flow behavior of the remaining oil in multiple regions (main flow channel, near flow channel, and far flow channel) was analyzed. Finally, the shape and number of remaining oil under different displacement stages were compared, and the occurrence mode of remaining oil under CFVAS displacement was determined. The results indicate the following: (1) During steam flooding, the amount of near flow channel residual oil decreased with injected pore volumes (PV), transforming into columnar structures in small perforations and film-like formations in far flow channels. (2) CFVAS flooding, including the foam stability mechanism, flow channel adjustment mechanism, and emulsification and dispersion mechanism, can improve overall recovery rates by 55.2% by driving the remaining oil in near flow channels. (3) During CFVAS flooding stage, crude oil mobility notably improved and flooding front expanded more evenly. Residual oil primarily existed as oil-in-water (O/W) emulsions with discontinuous columns. (4) In the CFVAS flooding stage, residual oil mainly formed O/W emulsions through emulsification and dispersion, with foam-filled large and medium pores, concentrating residual oil in thick and middle throats. This work can provide important references for injecting CO₂ gas into reservoirs to enhance heavy oil recovery and promote carbon sequestration. Full article

Carbon capture, utilization, and storage (CCUS) is an important component in many national net-zero strategies, and ensuring that CO₂ can be safely and economically stored in geological systems is critical. Recent discoveries have shown that microbial processes (e.g., methanogenesis) can modify fluid composition and fluid dynamics within the storage reservoir. Oil reservoirs are under high pressure, but the influence of pressure on the petroleum microbial community has been previously overlooked. To better understand microbial community dynamics in deep oil reservoirs, we designed an experiment to examine the effect of high pressure (12 megapascals [MPa], 60 °C) on nitrate-reducing, sulfate-reducing, and methanogenic enrichment cultures. Cultures were exposed to these conditions for 90 d and compared with a control exposed to atmospheric pressure (0.1 MPa, 60 °C). The degradation characteristic oil compounds were confirmed by thin-layer analysis of oil SARA (saturates, aromatics, resins, and asphaltenes) family component rods. We found that the asphaltene component in crude oil was biodegraded under high pressure, but the concentration of asphaltenes increased under atmospheric pressure. Gas chromatography analyses of saturates showed that short-chain saturates (C8–C12) were biodegraded under high and atmospheric pressure, especially in the methanogenic enrichment culture under high pressure (the ratio of change was −81%), resulting in an increased relative abundance of medium- and long-chain saturates. In the nitrate-reducing and sulfate-reducing enrichment cultures, long-chain saturates (C22–C32) were biodegraded in cultures exposed to high-pressure and anaerobic conditions, with a ratio of change of −8.0% and −2.3%, respectively. However, the relative proportion of long-chain saturates (C22–C32) increased under atmospheric pressure. Gas Chromatography Mass Spectrometry analyses of aromatics showed that several naphthalene series compounds (naphthalene, C1-naphthalene, and C2-naphthalene) were biodegraded in the sulfate-reducing enrichment under both atmospheric pressure and high pressure. Our study has discerned the linkages between the biodegradation characteristics of crude oil and pressures, which is important for the future application of bioenergy with CCUS (bio-CCUS). Full article

This study aims to identify the factors most likely to affect renewable energy consumption (REC) across mostly homogenous country groups worldwide. Classifying countries into a relatively homogenous group is taken from their economic and social development level measured with the Human Development Index. We delimited highly, medium-, and low-developed countries and checked whether the sets of determinants for using renewable energy sources are the same. We constructed a panel dataset as a basis for the panel Bayesian model averaging (panel BMA) as a factor selection method. The most likely factors were found and compared between the groups of countries. Then, the panel fixed-effects models for each country group were estimated. The results allowed us to confirm that CO₂ per capita emissions, terms of trade, GDP, foreign direct investment, crude oil price, and energy consumption from alternative sources are the most critical drivers of REC in group I. The most important factors in group II are CO₂ per capita, labor force, forest area, and gas and coal consumption. In the third group, REC consumption differs from that of the more advanced groups and strongly depends on foreign direct investment inflow. The results allow the formulation of policy recommendations on a global scale. Full article

Recently, there has been an increased focus on enhancing the accuracy of machine learning techniques. However, there is the possibility to improve it by selecting the optimal tuning parameters, especially when data heterogeneity and multicollinearity exist. Therefore, this study proposed a statistical model to study the importance of changing the crude oil prices in the European Union, in which it should meet state-of-the-art developments on economic, political, environmental, and social challenges. The proposed model is Elastic-net quantile regression, which provides more accurate estimations to tackle multicollinearity, heavy-tailed distributions, heterogeneity, and selecting the most significant variables. The performance has been verified by several statistical criteria. The main findings of numerical simulation and real data application confirm the superiority of the proposed Elastic-net quantile regression at the optimal tuning parameters, as it provided significant information in detecting changes in oil prices. Accordingly, based on the significant selected variables; the exchange rate has the highest influence on oil price changes at high frequencies, followed by retail trade, interest rates, and the consumer price index. The importance of this research is that policymakers take advantage of the vital importance of developing energy policies and decisions in their planning. Full article

Adequate nitrogen (N) and sulfur (S) fertilization of oilseed rape crops is necessary to obtain good-quality oil and post-extraction rapeseed meal. The aim of this study was to determine the effect of different doses of N fertilization (100, 160 and 220 kg ha⁻¹) and S (0, 30, 60 and 90 kg ha⁻¹) on the value of seeds of three winter oilseed rape genotypes. Two winter oilseed rape genotypes obtained by mutagenesis (cultivar Polka and breeding genotype PN440) were characterized by changed fatty acid profile. The cultivar Polka, type HO (high oleic), had a high content of oleic acid (C18:1, 78.0%) and the breeding genotype PN440, type HOLL (high-oleic and low-linolenic), had a high content of oleic acid (C18:1, 75.0%) and a low content of linolenic acid (C18:3, 3.0%). We also used the canola type of winter oilseed rape cultivar, Monolit. The analysed winter oilseed rape genotypes responded similarly to the N and S fertilization factors with regard to the content of crude fat and total protein in the seeds and the composition of fatty acids in the oil. N fertilization increased the content of glucosinolates (GLS-alkenyl, indole and total) in seeds, whereas S application decreased the content of saturated fatty acids (stearic acid-C18:0) in oil and increased the content of alkenyl and total glucosinolates (GLSs) in seeds. A significant interaction between N and S was observed for crude-fat and total-protein content. This study suggests that ensuring an adequate supply of both nitrogen and sulfur in the soil is essential for optimizing meal and oil quality in different types of winter oilseed rape cultivars. Proper management of these nutrients can lead to improved oil content and overall crop performance. Full article

This study examined the effect of experimental factors and conditions on the removal of nitrogen-containing heterocyclic compounds (NCHCs) by performing equilibrium extraction using formamide or formamide aqueous solution as a solvent to remove NCHCs contained in crude methylnaphthalene oil (CMNO). The CMNO used as a raw material in this study contained three types of NCHCs (quinoline, isoquinoline, and indole) classified as group A, and six kinds of non-NCHCs (naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, biphenyl, dibenzofuran, and fluorene) classified as group B. Increasing the volume fraction of water to the solvent before the extraction run increased the raffinate residual rate but conversely decreased the removal rate of group A. The increase in the volume fraction of solvent to feed before the extraction run and operating temperature decreased the residual rate of raffinate but conversely increased the removal rate of group A. Over the entire range of extraction conditions performed in this study, the removal rate of group A ranged from 10.8% to 70.7%. Considering that these experimental results were obtained using only a single stage of batch equilibrium extraction, the formamide extraction method applied in this study showed excellent performance in terms of the residual rate of raffinate and the removal rate of group A. Therefore, it was expected to be an alternative to the reaction extraction method using acids and bases applied so far to separate NCHCs in the distillation residue of coal tar. Full article

Crude oil and petroleum products contain various types of sulfur compounds: aliphatic and aromatic mercaptans, hydrogen sulfide, sulfides, disulfides, thiophene derivatives, etc. Some of these may dissolve in water only slightly, but their toxicity and corrosiveness indicate that even these small amounts should be eliminated from water. This work examines, for the first time, the removal of thiophenol (synonyms: benzenethiol, phenyl mercaptan) from water using sepiolite. This clay mineral (evaluated by SEM analysis) is an attractive natural sorbent characterized by its microporosity, which results from its crystalline structure and large specific surface area. Because the structure of thiophenol changes depending on the pH of the aqueous solution (due to the loss of a proton), the research was conducted at pH 4, 7 and 9. The detection of thiophenol in aqueous solution was investigated using UV spectroscopy. It was found that the adsorption of thiophenol is possible, but it occurs only in an acidic environment (pH 4). No sorption is observed at pH 7 or 9. The adsorption of thiophenol at pH 4 does not change significantly after changing the ionic strength of the aqueous solution (distilled water, 0.01 NaCl and 0.1 NaCl). The adsorption capacity of sepioliteis approximately 0.23–0.34 mg/g. Studies using infrared spectroscopy and fitting of Freundlich and Langmuir isotherm models to the results of adsorption experiments indicate that adsorption on unmodified sepiolite follows a physisorption mechanism. Additionally, to understand the behavior of thiophenol in the presence of sepiolite across different pH ranges, DFT/PCM/B3LYP/Aug-CC-pVDZ calculations were used to analyze the charge distribution on particular atoms in its structure. Full article

Asphaltene-resin-paraffin deposition (ARPD) is a complicated and prevalent issue in the oil and gas industry, impacting the efficiency and integrity of petroleum extraction, production, transportation and processing systems. Considering all witnessed ARPD problems in Azerbaijan oil fields, this paper proposed a chemical method and optimized the type and concentration of chemical inhibitors. Then, the effect of selected chemical reagents on inhibiting the ARPD amount and thus enhancing oil recovery was detected by reservoir simulation during both waterflooding and CO₂ flooding production. Three new chemical compounds (namely, Chemical-A, Chemical-B and Chemical-C) were examined in laboratory conditions, and their impact on rheological properties of high-paraffin oilfield samples of Azerbaijan (X, Y and Z) were investigated. Experimental results show that Chemical-C with a concentration of 600 g/t has the best efficiency for alleviating the problems. After adding Chemical-C to the crude oil, the freezing point of oil was decreased from 12 °C to (−4) °C, the ARPD amount declined from 0.185 to 0.016 g, and oil effective viscosity was reduced from 16.2 mPa·s to 3.1 mPa·s. It was determined that for water and CO₂ flooding, higher injection pressure resulted in reduced asphaltene precipitation. Adding the selected ARPD inhibitor, the oil recovery for waterflooding can increase from 52% to 62%, while it can rise from 55% to 68% for CO₂ flooding. Full article

Essential oils are natural feed additives that improve animal health and enhance their performance. This study investigated the effects of the rumen infusion of five essential oil blends (EOBs) on greenhouse gas (GHG) emissions, rumen fermentation parameters, and rumen metabolome and metabolic pathways in Black Angus cows. Using a 6 × 6 Latin Square experimental design, a 90-day study was conducted with six cattle. A daily dosage of 4 mL of EOBs was administered during each infusion. Volcano plot analyses between the control (CON) and each of the EOBs (EOB1, EOB2, EOB3, EOB4, and EOB5) revealed several differentially abundant (p ≤ 0.05; absolute fold change ≥1.5) metabolites. The EOB5 treatment exhibited the most significant impact, with 26 differentially abundant metabolites, including elevated valine and reduced gallic acid. Volatile fatty acids (VFAs), including valerate, isobutyrate, and isovalerate, were significantly increased (p < 0.05). GHG emissions were not significantly affected, but a numerical decrease was observed in the animals infused with the EOB5 treatment. Ammonia nitrogen concentrations remained within the suitable range for rumen microbes’ growth, indicating a normal internal environment for microbial crude protein synthesis. In conclusion, the study has demonstrated that the direct infusion of EOBs significantly improved the generation of VFAs and impacted the energy production, protein synthesis, and microbial activity of the animals. Full article

Botanical insecticides and soaps are frequently proposed as environmentally safer alternatives to synthetic insecticides. However, the efficacy and selectivity of these products are often only partially supported by empirical evidence. Here, we tested the effectiveness of five botanical insecticides, belonging to different categories, on the green peach aphid Myzus persicae (Sulzer) and their selectivity towards two natural enemies, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). White thyme essential oil (EO), sweet orange EO, crude garlic extract and Marseille soap were tested and compared with a pyrethrin-based commercial product. Both direct spray assays and residual contact assays on treated cabbage leaf disks were carried out. The tested products had low efficacy against aphids when compared to pyrethrins but were in general less detrimental to ladybird beetle larvae, meaning that if applied against other pests, they have a lower chance of harming this agent of aphid biocontrol. Some of the products (soap, orange EO) did, however, show direct exposure toxicity toward ladybird larvae, and thyme EO had extensive phytotoxic effects on cabbage leaves, possibly indirectly leading to higher mortality in ladybird adults. These results underline the necessity for case-by-case evaluations of botanical insecticides. Full article

The paper presents the results of a systematic microfluidic study of the application of nanosuspensions for enhanced oil recovery. For the first time, approximately a dozen nanosuspensions prepared by the dilution of silica sols as displacement fluids were considered. The concentration of nanoparticles in the suspensions varied from 0.125 to 2 wt%, and their size ranged from 10 to 35 nm. Furthermore, the silica sols under consideration differed in their compositions of functional groups and pH. The effects of concentration, nanoparticle size, fluid flow rate, and the viscosity of the displaced oil were investigated using microfluidic technology. The microfluidic experiments demonstrated that the application of nanosuspensions for water flooding has significant potential. The efficiency of oil displacement by nanosuspensions was found to increase significantly (up to 30%) with the increasing concentration and decreasing average size of nanoparticles. The application of nanosuspensions for the enhancement of oil recovery is most appropriate for reservoirs with highly viscous oil. Full article

Ultrasonic technology, which has been receiving increasing attention from the petroleum industry, has emerged as a promising environmentally-friendly technology due to its high adaptability, simple operation, low cost, and lack of pollution; the mechanisms of this technology are clarified herein. At the same time, this paper presents a comprehensive review of the impact of ultrasound on enhanced oil recovery (EOR) by removing plugs, reducing oil viscosity, and demulsifying crude oil, while highlighting the latest advancements in this field. Lastly, this paper delves into the challenges and prospects associated with the industrial implementation of power ultrasound. The objective of this review is to provide a comprehensive overview of recent advancements, serving as a valuable reference for future investigations on ultrasound-assisted EOR. Oil field results demonstrate that oil production increased by 26.5% to 100%, water cut decreased by 5% to 96%, the success rate ranged from 75% to 90%, and the effect can last for a duration of 4 h to 12 months. Full article

The Lunnan oilfield, nestled within the Tarim Basin, represents a prototypical extra-low-permeability sandstone reservoir, distinguished by high-quality crude oil characterised by a low viscosity, density, and gel content. The effective exploitation of such reservoirs hinges on the implementation of carbon dioxide (CO₂) flooding techniques. This study, focusing on the sandstone reservoirs of Lunnan, delves into the mechanisms of CO₂-assisted oil displacement under diverse operational parameters: injection pressures, CO₂ concentration levels, and variations in crude oil properties. It integrates analyses on the high-pressure, high-temperature behaviour of CO₂, the dynamics of CO₂ injection and expansion, prolonged core flood characteristics, and the governing principles of minimum miscible pressure transitions. The findings reveal a nuanced interplay between variables: CO₂’s density and viscosity initially surge with escalating injection pressures before stabilising, whereas they experience a gradual decline with increasing temperature. Enhanced CO₂ injection correlates with a heightened expansion coefficient, yet the density increment of degassed crude oil remains marginal. Notably, CO₂ viscosity undergoes a substantial reduction under stratigraphic pressures. The sequential application of water alternating gas (WAG) followed by continuous CO₂ flooding attains oil recovery efficiency surpassing 90%, emphasising the superiority of uninterrupted CO₂ injection over processes lacking profiling. The presence of non-miscible hydrocarbon gases in segmented plug drives impedes the oil displacement efficiency, underscoring the importance of CO₂ purity in the displacement medium. Furthermore, a marked trend emerges in crude oil recovery rates as the replacement pressure escalates, exhibiting an initial rapid enhancement succeeded by a gradual rise. Collectively, these insights offer a robust theoretical foundation endorsing the deployment of CO₂ flooding strategies for enhancing oil recovery from sandstone reservoirs, thereby contributing valuable data to the advancement of enhanced oil recovery (EOR) technologies in challenging, low-permeability environments. Full article

With the daily use of liquid cargoes such as crude oil and their derivatives, the global transportation of liquid cargoes has developed rapidly. Liquid cargoes are mainly transported via tankers and pipelines. In the liquid terminal, the handling operations and internal transportation operations are conducted using oil transfer arms and pipelines, and the pipeline path of the cargo is selected using valves. The number of times a valve opens and closes and the length of pipeline paths are the main factors that affect handling time and cost. In addition, different types of valves have different operating costs and levels of operating energy consumption. At this stage, most of the valve selection work is still manually completed, which consumes a lot of time and generates high labor costs, and the actual operation efficiency is low. In this paper, the cargo unloading pipeline path is the main research object, the problem of oil transfer arms–valves–pipeline (PAVP) is proposed, and a dual-objective model is established, accounting for total time in port and the unloading cost of the vessel. An NSGA-II-Dijkstra hybrid algorithm is employed to solve the PAVP, and the improved algorithm (INIIDA) is designed to improve the solution speed via an adaptive dynamic probability based on the Pareto level and heaps in the shortest path. The results show that the INIIDA could better address the PAVP than the NSGA-II-Dijkstra hybrid algorithm. Innovative fusion algorithms are employed to improve the efficiency of port operations. Full article