Search Results (117)

The Threshold Pressure Gradient (TPG) phenomenon exerts a profound influence on fluid flow dynamics in heavy oil reservoirs. However, the discrepancies between the True Threshold Pressure Gradient (TTPG) and Pseudo-Threshold Pressure Gradient (PTPG) significantly impede accurate residual oil evaluation and rational field development planning. This study proposes a dual-exponential conversion model that effectively bridges the discrepancy between TTPG and PTPG, achieving an average deviation of 12.77–17.89% between calculated and measured TTPG values. Nonlinear seepage simulations demonstrate that TTPG induces distinct flow barrier effects, driving residual oil accumulation within low-permeability interlayers and the formation of well-defined “dead oil zones.” In contrast, the linear approximation inherent in PTPG overestimates flow initiation resistance, resulting in a 47% reduction in recovery efficiency and widespread residual oil enrichment. By developing a TTPG–PTPG conversion model and incorporating genuine nonlinear seepage characteristics into simulations, this study effectively mitigates the systematic errors arising from the linear PTPG assumption, thereby providing a scientific basis for accurately predicting residual oil distribution and enhancing oil recovery efficiency. Full article

Numerous studies have been conducted employing various techniques to remove pollutants from water bodies. Among these techniques, adsorption a surface phenomenon that utilises adsorbents derived from agricultural residues has shown considerable potential for the removal of contaminants such as heavy metals. However, most of these investigations have been carried out at the laboratory scale, with limited efforts directed towards predicting the performance of these systems at an industrial level. Accordingly, the present study aims to model a packed bed column at industrial scale for the removal of Pb(II) and Ni(II) ions from aqueous solutions, employing biomass derived from oil palm residues as the adsorbent material. To achieve this, Aspen Adsorption was used as a modelling and simulation tool to evaluate the impact of bed height, inlet flow rate, and initial concentration through a parametric assessment. This evaluation incorporated the Freundlich, Langmuir, and Langmuir–Freundlich isotherm models in conjunction with the Linear Driving Force (LDF) kinetic model. The results indicated that the optimal operating parameters included a column height of 5 m, a flow rate of 250 m³/day, and an initial metal concentration of 5000 mg/L. Moreover, all models demonstrated removal efficiencies of up to 94.6% for both Pb(II) and Ni(II). An increase in bed height resulted in longer breakthrough and saturation times but led to a reduction in adsorption efficiency. Conversely, higher flow rates shortened these times yet enhanced efficiency. These findings underscore the potential of computational modelling tools as predictive instruments for evaluating the performance of adsorption systems at an industrial scale. Full article

Heavy oil, due to its complex hydrocarbon structure and resistance to degradation, poses significant environmental challenges. There is a lack of knowledge about the biodegradability of heavy oil in the natural environment under aerobic and anaerobic conditions. In this study, we used microbial communities of water and soil samples to investigate the biodegradation of heavy oil. Gas chromatography (GC) analysis was used to measure residual oil. Under aerobic conditions, soil-derived microorganisms demonstrated significantly higher degradation efficiency—achieving up to 80.3% removal—compared to water-derived samples, which showed a maximum degradation of 52.1%. Anaerobic conditions, on the other hand, clearly slowed down degradation; the maximum degradation rates in water and soil samples were 43.7% and 11.1%, respectively. Although no clear linear relationship was found, the correlation between initial microbial populations and degradation performance revealed that higher counts of heterotrophic and oil-degrading bacteria generally enhanced biodegradation. Under anaerobic conditions, especially, persistent hydrocarbon peaks in both environments suggest the presence of recalcitrant heavy oil fractions such as polycyclic aromatic hydrocarbons. In conclusion, this study emphasizes the crucial roles microbial sources and oxygen availability play in maximizing bioremediation techniques for environments contaminated with heavy oil. Full article

The massive heavy oil reserves in the Athabasca region of northern Alberta depend on steam-assisted gravity drainage (SAGD) for their economic exploitation. Even though SAGD has been successful in highly viscous oil recovery, it is still a costly technology because of the large energy input requirement. Large water and natural gas quantities needed for steam generation imply sizable greenhouse gas (GHG) emissions and extensive post-production water treatment. Several methods to make SAGD more energy-efficient and environmentally sustainable have been attempted. Their main goal is to reduce steam consumption whilst maintaining favourable oil production rates and ultimate oil recovery. Oil saturation within the steam chamber plays a critical role in determining both the economic viability and resource efficiency of SAGD operations. However, accurately quantifying the residual oil saturation left behind by SAGD remains a challenge. In this experimental research, sand pack Expanding Solvent SAGD (ES-SAGD) coinjection experiments are reported in which Pentane -C₅H₁₂, and Hexane -C₆H₁₄ were utilised as an additive to steam to produce Long Lake bitumen. Each solvent is assessed at three different constant concentrations through time using experiments simulating SAGD to quantify their impact. The benefits of single-component solvent coinjection gradually diminish as the SAGD process approaches its later stages. ES-SAGD pentane coinjection offers a smaller improvement in recovery factor (RF) (4% approx.) compared to hexane (8% approx.). Between these two single-component solvents, 15 vol% hexane offered the fastest recovery. The obtained data in this research provided compelling evidence that the coinjection of solvent under carefully controlled operating conditions, reduced overall steam requirement, energy consumption, and residual oil saturation allowing proper adjustment of oil and water relative permeability curve endpoints for field pilot reservoir simulations. Full article

In this study, we investigated the solvent performance of six heavy oils from Xinjiang, China, for coal–oil co-liquefaction (COCL). Autoclave experiments revealed that shale oil vacuum residue (SOVR) provided the best liquefaction performance. The oils were characterized using FT-IR, ¹³C-NMR, ¹H-NMR, and column chromatography, which revealed that they were mainly composed of aliphatic compounds, with minor aromatic and substituted aromatic compounds. The pyrolytic degradation quality indices (PDQIs), solubility parameter (δ_C), and polycyclic aromatic hydrocarbon content (H_A2 + H_A3) were calculated and correlated with liquefaction performance. The results showed a strong linear relationship between H_A2 + H_A3 and oil yield (R² = 0.90), and the aromatic content (AR) was also positively related to oil yield. This study suggests that AR content and H_A2 + H_A3 are effective indicators for evaluating the solvent performance of heavy oils in COCL. Full article

Water injection is the most widely used secondary recovery method, but its low viscosity limits sweep efficiency in heterogeneous carbonate reservoirs, especially when displacing heavy crude oils. Polymer flooding overcomes this by increasing the viscosity of the injected fluid and improving the mobility ratio. In this work, we compare three biopolymers (i.e., Xanthan Gum, Scleroglucan, and Guar Gum) using a core flood test on Indiana Limestone with 16–19% porosity and 180–220 mD permeability at 60 °C and 30,905 mg/L of salinity. We injected solutions at 100–1500 ppm and 0.5–6 cm³/min to measure the Resistance Factor (RF), Residual Resistance Factor (RRF), in situ viscosity, and relative injectivity. All polymers behaved as pseudoplastic fluids with no shear thickening. The RF rose from ~1.1 in the dilute regime to 5–16 in the semi-dilute regime, and the RRF spanned 1.2–5.8, indicating moderate, reversible permeability impairment. In-site viscosity reached up to eight times that of brine, while relative injectivity remained 0.5. Xanthan Gum delivered the highest viscosity boost and strongest shear thinning, Scleroglucan offered a balance of stable viscosity and a moderate RF, and Guar Gum gave predictable but lower viscosity enhancement. These results establish practical guidelines for selecting polymer types, concentration, and flow rate in reservoir-condition polymer flood designs. Full article

The production of very-low-sulfur residual fuel oil is a great challenge for modern petroleum refining because of the instability issues caused by blending incompatible relatively high-sulfur residual oils and ultra-low-sulfur light distillates. Another obstacle in the production of very-low-sulfur residual fuel oil using hydroprocessing technology is the contradiction of hydrodesulfurization with hydrodemetallization, as well as the hydrodeasphaltization functions of the catalytic system used. Therefore, the production of very-low-sulfur residual fuel oil by employing hydroprocessing could be achieved by finding an appropriate residual oil to be hydroprocessed and optimal operating conditions and by controlling catalyst system condition management. In the current study, data on the characteristics of 120 samples of heavy fuel oils produced regularly over a period of 10 years from a high-complexity refinery utilizing H–oil vacuum residue hydrocrackers in its processing scheme, the crude oils refined during their production, the recipes of the heavy fuel oils, and the level of H–oil vacuum residue conversion have been analyzed by using intercriteria and regression analyses. Artificial neural network models were developed to predict the characteristics of hydrocracked vacuum residues, the main component for the production of heavy fuel oil. It was found that stable very-low-sulfur residual fuel oil can be manufactured from crude oils whose sulfur content is no higher than 0.9 wt.% by using ebullated bed hydrocracking technology. The diluents used to reduce residue viscosity were highly aromatic FCC gas oils, and the hydrodemetallization rate was higher than 93%. Full article

The study of thermal developments of heavy oil feedstock, vacuum residue in particular, is a relevant factor for the development of technologies for the processing and production of petroleum products. This paper investigates the process of thermal decomposition of the vacuum residue in the manufacturing of catalyst and polymer material using thermal analysis methods, including thermogravimetric analysis (TGA) in isothermal and dynamic modes. Particular attention is paid to the measurement of kinetic parameters of thermolysis using model and non-model methods, which allows us to assess the output power and other kinetic characteristics of decomposition. The results obtained can be used for the development of new oil refining technologies for significantly increasing the efficiency and safety of processes. During the course of this study, experimental and theoretical activation energy values were obtained for the vacuum residue without a catalyst (experimentally: 91.54 kJ mol⁻¹/theoretically: 91.35 kJ mol⁻¹) and a sample with the presence of a catalyst (experimentally: 89.68 kJ mol⁻¹/theoretically: 90.87 kJ mol⁻¹). The reduction in activation energy in the presence of the catalyst confirms its catalytic activity and potential for processing heavy hydrocarbon feedstock. Full article

The effective management of produced water (PW), a by-product of oil extraction in Oman, is essential for sustainable water use and environmental protection. PW contains petroleum residues, heavy metals, and salts, which require treatment before safe reuse. In the Nimr oil field, PW undergoes partial treatment in constructed wetlands vegetated with buffelgrass (Cenchrus ciliaris). This study investigated the reuse potential of treated PW for irrigation through two parallel field experiments conducted at Sultan Qaboos University (SQU) and the Nimr wetlands site. At the SQU site, native halophytic plants were irrigated with three water sources: treated municipal wastewater, underground water (from an on-site well), and treated produced water. At the Nimr site, irrigation was conducted using underground water and treated PW. Two soil types were used: well-draining control soil and Nimr soil from southern Oman. The treatments included: (i) PW + control soil, (ii) PW + Nimr soil, (iii) PW + gypsum (3.5 g/kg soil), (iv) PW + biochar (10 g/kg soil), (v) underground water + control soil, and (vi) treated municipal wastewater + control soil. Biochar, produced from locally sourced buffelgrass via low-temperature pyrolysis (300 °C for 3 h), and gypsum (46.57% acid-extractable sulfate) were mixed into the soil before sowing. The impact of each treatment was assessed in terms of soil quality (salinity, boron, major cations), plant physiological responses, and mineral accumulation. PW irrigation (TDS ~ 6500–7000 mg/L) led to a sixfold increase in soil sodium and raised boron levels in plant tissues to over 200 mg/kg, exceeding livestock feed safety limits. Copper remained within acceptable thresholds (≤9.5 mg/kg). Biochar reduced boron uptake, but gypsum showed limited benefit. Neither amendment improved plant growth under PW irrigation. These findings highlight the need for regulated PW reuse, emphasizing the importance of soil management strategies and alternating water sources to mitigate salinity stress. Full article

China’s natural gas demand is growing under the “dual carbon” goal. However, the peaking capacity of gas storage remains insufficient. Oil reservoir-based underground gas storage (UGS) has, thus, emerged as a critical research focus due to its potential for efficient capacity expansion. The complexity of seepage and phase change characteristics during the multi-cycle injection–production process has not been systematically elucidated. This study combines experimental and numerical simulations to examine the seepage and phase change characteristics. This study innovatively reveals the synergistic mechanism of permeability, pressure, and cycle. The control law of multi-factor coupling on the dynamic peaking capacity of UGS is first expounded. Oil–water mutual drive reduced oil displacement efficiency by 2.5–4.7%. Conversely, oil–gas mutual drive improved oil displacement efficiency by 3.0–4.5% and storage capacity by 4.7–6.5%. The fifth-cycle oil–gas mutual displacement in high-permeability cores (74 mD) under high pressure (22 MPa) exhibited reductions in irreducible water saturation (7.06 percentage points) and residual oil saturation (6.38 percentage points) compared with the first-cycle displacement in low-permeability cores (8.36 mD) under low pressure (16 MPa). Meanwhile, the gas storage capacity increased by 13.44 percentage points, and the displacement efficiency improved by 10.62 percentage points. Multi-cycle huff-and-puff experiments and numerical simulations revealed that post-depletion multi-cycle huff-and-puff operations can enhance the oil recovery factor by 2.74–4.22 percentage points compared to depletion. After five-cycle huff-and-puff, methane content in the produced gas increased from 80.2% to 87.3%, heavy components (C₈₊) in the remaining oil rose by 2.7%, and the viscosity of the remaining oil increased from 2.0 to 4.6 mPa·s. The deterioration of the physical properties of the remaining oil leads to a reduction in the recovery factor in the cycle stage. This study elucidates seepage mechanisms and phase evolution during multi-cycle injection–production, demonstrating the synergistic optimization of high-permeability reservoirs and high-pressure injection techniques for enhanced gas storage design and efficiency. Full article

The residue conversion processes, coking, visbreaking, and fluid catalytic cracking (FCC), have demonstrated that feedstock quality is the single factor that most affects process performance. While, for the FCC, it is known that the heavy oil conversion at a maximum gasoline yield point can vary between 50 and 85 wt. %, for the vacuum residue hydrocracking, no reports have appeared yet to reveal the dependence of conversion on the quality of vacuum residue being hydrocracked. In order to search for such a dependence, eight vacuum residues derived from medium, heavy, and extra heavy crude oils have been hydrocracked in a laboratory unit at different reaction temperatures. The current study has witnessed that the vacuum residue hydrocracking obeys the same rule as that of the other residue conversion processes, confirming that the feedstock quality has a great influence on the process performance. A conversion variation between 45 and 85 wt. % can be observed when the sediment content in the hydrocracked atmospheric residue is within the acceptable limit, guaranteeing the planned cycle length. An intercriteria analysis was performed, and it revealed that the vacuum residue conversion has negative consonances with the contents of nitrogen and metals. Correlations were developed which predict the conversion at constant operating conditions within the uncertainty of conversion measurement of 1.7 wt. % and correlation coefficient of 0.964. The conversion at constant hydrocracked atmospheric residue (HCAR) sediment content was predicted with a correlation coefficient of 0.985. The correlations developed in this work disclosed that the higher the contents of metals, nitrogen, and asphaltenes, and the lower the content of sulfur, the lower the conversion in the hydrocracking process is. It was also shown that vacuum residues, which have the same reactivity (the same conversion at identical operating conditions), can indicate significant difference in the conversion at the same HCAR sediment content due to their diverse propensity to form sediments in the process of hydrocracking. Full article

Oil spills represent a significant environmental hazard, particularly in marine ecosystems, where their impacts extend to coastal infrastructure, biodiversity, and economic activities. This study utilizes GNOME v.47.2 (General NOAA Operational Modeling Environment) and ADIOS2 v.2.10.2 (Automated Data Inquiry for Oil Spills) to simulate and analyze oil spill dynamics in the Romanian sector of the Black Sea, focusing on trajectory prediction, hydrocarbon weathering, and shoreline contamination risk assessment. The research explores multiple spill scenarios involving different hydrocarbon types (light vs. heavy oils), vessel dynamics, and real-time environmental variables (wind, currents, temperature). The findings reveal that lighter hydrocarbons (e.g., gasoline, aviation fuel) tend to evaporate quickly, while heavier fractions (e.g., crude oil, fuel oil #6) persist in the marine environment and pose a higher risk of coastal pollution. In the first case study, a spill of 10,000 metric tons of medium oil (Arabian Medium EXXON) was simulated using GNOME v.47.2, showing that after 22 h, the slick reached the shoreline. Under forecasted hydro-meteorological conditions, 27% evaporated, 1% dispersed, and 72% remained for mechanical or chemical intervention. In the second simulation, 10,000 metric tons of gasoline were released, and within 6 h, 98% evaporated, with only minor residues reaching the shore. A real-world validation case was also conducted using the December 2024 Kerch Strait oil spill incident, where the model accurately predicted the early arrival of light fractions and delayed coastal contamination by fuel oil carried by subsurface currents. These results emphasize the need for future research focused on the vertical dispersion dynamics of heavier hydrocarbon fractions. Full article

The efficient utilization of heavy oil is of great significance to alleviating the global energy crisis. How to efficiently convert heavy oil into high-value-added light fuel oil has become a hot issue in the field of petrochemicals. As the residual part of crude oil processing, heavy oil has a complex composition and contains polycyclic aromatic hydrocarbons, long-chain alkanes, and heteroatom compounds, which makes it difficult to process directly. Zeolite, as an important type of solid acid catalyst, has a unique pore structure, adjustable acidity, and good thermal stability. It can promote the efficient cracking and conversion of heavy oil molecules, reduce coke formation, and improve the yield and quality of light oil products. This paper systematically reviews the development status of heavy oil cracking technology, focusing on the structural characteristics, acidity regulation of zeolite catalysts, and their applications in heavy oil cracking and hydrocracking. The mechanism of the cracking reaction of polycyclic aromatic hydrocarbons and long-chain alkanes is analyzed in detail, and the catalytic characteristics and modification methods of zeolite in the reaction process are explained. In addition, this paper summarizes the main challenges faced by zeolite catalysts in practical applications, including uneven acidity distribution, limited pore diffusion, and easy catalyst deactivation, and proposes targeted development strategies. Finally, this paper looks forward to the future development direction of zeolite catalysts in the field of heavy oil cracking and upgrading reactions, emphasizes the importance of structural optimization and multi-scale characterization, and provides theoretical support and practical reference for the design and industrial application of efficient zeolite catalysts. Full article

In view of the limited applicability of traditional chemical flooding and binary composite flooding for heavy-oil reservoirs, branched-preformed particle gel (B-PPG) with excellent plugging performance was added to construct the B-PPG/SP (B-PPG/surfactant/polymer) composite system. Through sand pack flooding experiments, it has been proven that the synergistic effect between B-PPG and polymer can expand the swept area and increase the contact between the viscosity reducer and heavy oil, enabling the viscosity reducer to better exert emulsification and viscosity reduction effects. The synergistic effect between B-PPG, polymer and viscosity reducer can further expand the swept area and oil displacement efficiency, ultimately enhancing the heavy-oil recovery by 37.8%. Microscopic visualization flooding experiments proved that cluster remaining oil accounts for the largest proportion in the microscopic remaining oil in heavy oil. By adding B-PPG and polymers, cluster remaining oil can be effectively displaced, thereby significantly enhancing the heavy-oil recovery. And adding viscosity reducer to the composite system can effectively enhance the dispersed residual oil recovery within the swept area. The sand pack flooding experiments with different heavy-oil viscosity proved that the optimal oil viscosity of the B-PPG/SP composite system can reach 657.2 mPa·s, with an incremental oil recovery rate increase of 30.2%. Full article

This article considers modern approaches to obtaining synthetic oil from unconventional hydrocarbon feedstocks, including plastic waste, tires, biomass, coal, and extra-heavy oil. Particular attention is paid to multi-stage technologies, such as pyrolysis, catalytic depolymerization, gasification followed by Fischer–Tropsch synthesis, and hydrocracking of heavy residues. The important role of catalysts in increasing the selectivity and economic efficiency of processes is noted: nanostructured, bifunctional, and pollution-resistant systems are increasingly used. Economic factors influencing the competitiveness of this industry are considered, including the volatility of prices for traditional oil, government support measures, and the development of waste logistics infrastructure. It is emphasized that the strengthening of the position of synthetic oil is associated with the growth of environmental requirements stimulating the recycling of plastics, tires, and biomass; at the same time, compliance with high environmental standards and transparency of emission control play a critical role in the social aspects of projects. In addition to improving the environmental situation, the development of synthetic oil contributes to the creation of jobs, the resolution of problems of shortage of classical oil fields, and the increase of energy security. It is concluded that further improvement of technologies and integration into industrial clusters can turn this sphere into a significant component of the future energy sector. Full article