Crude Oil Composition Research Articles

Prediction of the minimum miscibility pressure for CO2 flooding based on a physical information neural network algorithm

Abstract The minimum miscibility pressure (MMP) is a crucial parameter in assessing the miscibility of CO2 displacement and evaluating the effectiveness of oil displacement. Traditional methods for calculating MMP are intricate and time-consuming, involving numerous related parameters. Therefore, precise and efficient determination of MMP is highly significant in the development of CO2-driven reservoirs. This study first utilized the Pearson correlation coefficient to analyse the correlation factor mechanism of 36 sets of fine-tube experimental data. Subsequently, the physical information neural network prediction model was employed with reservoir temperature, crude oil composition, and injected gas type as input parameters. The PRI state equation and Glaso correlation equation drove the model, with parameter optimization and training conducted under both physical and data driving. The model demonstrates high prediction accuracy and strong generalization ability. Finally, Validation of the model was performed using fine-tube experimental data from 5 other wells, revealing a relatively small relative deviation between calculated and experimental values, with an average coefficient of determination of 0.95 and an average relative error of 4.42%. The prediction accuracy was improved by about 75% compared to other machine learning algorithms. This model holds potential for application in on-site reservoir development, enhancing the measurement accuracy of the minimum miscible pressure of pure CO2 flooding, greatly shortening the design cycle of reservoir development, expediting the process of reservoir development, and providing technical guidance for improving oil and gas recovery and pure CO2 flooding exploration and development.

Innovations in Crude-Oil Characterization: A Comprehensive Review of LF-NMR Applications

The advent of low-field nuclear magnetic resonance (LF-NMR) has revolutionized the petroleum industry by providing a swift and straightforward method for the spectroscopic characterization of crude oil. This review paper delves into the significant strides made in LF-NMR technology since its inception by Felix Bloch and Edward Purcell in 1946, particularly its application in determining the composition, viscosity, and water content of crude oil, alongside SARA (Saturates, Aromatics, Resins, and Asphaltenes) analysis. LF-NMR’s ability to noninvasively quantify the total water and oil content, differentiate between bound and mobile phases, and measure the SARA fractions underscores its superiority over traditional analysis methods, which often suffer from interference and lack of precision. This manuscript not only highlights LF-NMR’s pivotal role in enhancing crude-oil characterization but also reviews recent developments that solidify its position as an indispensable tool in the petroleum industry. The convergence of empirical studies and technological advancements points toward a pressing need for further research to fully exploit LF-NMR’s potential and refine its application, ensuring its continued contribution to the efficient and accurate analysis of petroleum products.

Nutritional composition, fatty acids, bioactive compounds, and antioxidant activity of Nigella sativa seed grown in Bangladesh

Black cumin seeds are extensively utilized for foods, cosmetics, and medicinal purposes. The current investigation was undertaken to analyzse the nutritional values, fatty acid compositions, bioactive compounds, and antioxidant roles of different black cumin genotypes available in Bangladesh. The genotype BSK-2074 had a higher content of proximate composition of crude oil (35.17%), crude protein (23.51%), total carbohydrate (35.23%), moisture (6.54%), ash (3.74%), crude fiber (8.12%), and gross energy value (644.88 kcal/100 g) than the released varieties and cultivars of black cumin available in Bangladesh. The major fatty acid profile of the seed-oil of the BSK-2074 genotype revealed that the oil contained a high amount of linoleic (59.39%), oleic (25.72%), palmitic (13.11%), and stearic (2.25%) acids, as well as a low amount of arachidic, linolenic, myristic, behenic, palmitoleic, lignoceric, and eicosadienoic acids. Moreover, the genotype BSK-2074 contained a high amount of unsaturated (UFAs, 85%), and low content of saturated (SFAs, 18%) fatty acids, and the ratio of UFAs to SFAs was higher (4.39–5.37). Again, the seeds of the genotype BSK-2074 were also enriched in different minerals, viz., calcium, magnesium, potassium, phosphorus, iron, and zinc. Moreover, total phenolic contents (TPC) and flavonoid contents (TFC) were found significantly higher in the genotype BSK-2074 (478.47 ± 7.33 mg GAE/100 g and 284.07 ± 2.08 mg QE/100 g, respectively) than the local Kalozira variety (316.48 ± 2.33 mg GAE/100 g and 120.53 ± 3.57 mg QE/100 g) found in Bangladesh. The activities of antioxidants 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals and ferric reducing antioxidant power (FRAP) were found significantly higher in BSK-2074 (37.93% and 129.65 ± 0.19 mg GAE/100 g), than the local Kalozira variety (98.09% and 193.75 ± 0.19 mg GAE/100 g). Thus, the new genotype, BSK-2074, was identified and suggested as the most promising and nutritionally enriched genotype of black cumin.

Essential oil of endemic Centaurea paphlagonica: chemical composition, insecticidal, enzyme inhibitory activities and molecular docking approach

The key objective of this study was to determine the chemical composition, insecticidal and butyrylcholinesterase (BChE) inhibitory activities of crude essential oils (CEO) extracted from the stem-leaf parts of the endemic Centaurea paphlagonica plant via steam distillation, as well as its chromatography-based fractions for the first time. According to GC-MS analysis, eighty-five compounds were identified representing 98.49% of the total essential oil. β-Eudesmol (15.17%), phytol (8.69%), and spathulenol (8.03%) were determined as the main components. The CEO demonstrated a remarkably insecticidal activity against S. granarius and R. dominica insects, ranging from 98.35% to 100%, while achieving a 50% against T. confusum at a 10% concentration. The silica gel-based fractionation of CEO resulted in four qualitatively different fractions (CEO-F1 to F4). The CEO-F2, predominantly comprised of β-eudesmol and spathulenol, exhibited superior activity compared to CEO across all tested insects. In addition, the inhibitory activity of BChE, which causes death in insects by altering nervous system activities, was assessed. BChE inhibition activity of CEO and CEO-F2 was determined as IC50=346.57 μg/mL and 96.02 μg/mL, respectively, supporting the insecticidal activity tests and molecular docking studies. The volatile oil obtained from C. paphlagonica can be considered a potential natural source to combat storage product pests, with its significant natural volatile compounds.

Modeling the Effect of Sulfur Composition in Dispersed Systems Involving Organosulfur Compounds

Background:: Organosulfur compounds within petroleum have far-reaching consequences for the refining industry, combustion of petroleum products, and environmental quality. They induce corrosion in refining equipment, hamper the efficient burning of petroleum products, and contribute to environmental degradation. In high-density asphalt crudes, these compounds are predominantly concentrated within asphaltenes. However, crude oils with extremely high sulfur content, may be distributed across the four constituent families defined by the SARA analysis of crude oil composition. These compounds, characterized by differing polarities, can trigger the formation of a dispersed phase, whose destabilization results in tube clogging issues. Methods:: The research problem focuses on understanding how sulfur composition affects the formation of a dispersed phase in low-polarity organic dispersion media for sulfur-containing hydrocarbons. It is investigated because the presence of sulfur in crude oil significantly affects the behavior of dispersed phases, which can result in operational and environmental quality issues to comprehensively assess the impact of sulfur composition on the dynamics and stability of this dispersed phase, we introduce a mesoscopic model based on the master equation. This model considers the molecular structure of system components and their molecular properties, established through computational quantum chemistry and statistical thermodynamics tools Results:: While our research focuses on a two-phase system, our theoretical insights suggest that increased sulfur content escalates the likelihood of destabilizing the dispersed phase. This adverse effect can be mitigated by incorporating additives capable of reducing the polarizability of the dispersion medium. The novelty lies in the development of a stochastic model to predict the dynamics of dispersed phase formation in sulfur-containing hydrocarbons. This model considers molecular interactions and stochastic processes, offering insights into the influence of sulfur composition on phase behavior. Conclusion:: A stochastic model, based on molecular structure, predicts accelerated formation with increased sulfur concentration, reaching non-equilibrium steady states. Limitations include ad hoc transition probabilities and the exclusion of factors like density and viscosity. Real crudes, with complex compositions, may exhibit different behavior. The presence of sulfur in the dispersion medium enhances the stability of the dispersed system. Our work sheds light on the intricate interplay between sulfur content and the performance of petroleum systems, offering potential solutions to mitigate these issues. Quantitative results include accelerated dispersed phase formation with increased sulfur concentration. Qualitatively, molecular interactions and stochastic processes were explored, highlighting sulfur's impact on phase dynamics.

Surface modeling of wettability transition on α-quartz: Insights from experiments and molecular dynamics simulations

The wettability of quartz surfaces is a critical property in numerous energy-related industrial processes. However, accurately quantifying wettability is challenging due to the multitude of factors that can influence wetting behavior. Herein, we proposed a generalized surface modeling procedure addressing microscopic insights to calculate the contact angles of liquids on quartz under different scenarios. An optical goniometer experimentally measured the contact angles and validated the proposed surface modeling procedure. The effects of surface density of hydroxyl groups, temperature, surfactants, and crude oil composition on the wettability of quartz surfaces were studied. The results revealed that an increased hydroxyl group density significantly improved water wettability on a quartz surface. An increased temperature reduced the water contact angle on quartz, and such decreasing rates became steeper at high temperatures. The surfactants’ adsorption morphology determined the wettability of a quartz surface. Moreover, the polar components in crude oil significantly increased the hydrophobicity of a quartz surface, making it easier to adsorb more oil molecules to alter the quartz wettability further. The valuable outcomes of this paper contribute to understanding the complex quartz wettability and pave the way for further studies involving quartz surface modeling.

Laboratory study on the transformation of oil-water interface properties under direct current electric field

Interface tension is one of the important mechanisms that affect crude oil recovery and plays an important role in the development of tight oil reservoirs. Electrical-enhanced oil recovery can be used as a technology to reduce interfacial tension and improve crude oil recovery. In the previous research process of Electrical-enhanced oil recovery, the focus was more on the influence of electric field on wettability, and the understanding of the changes in interfacial tension under electric field action is not yet comprehensive. This article designs an orthogonal experiment to study the effect of electric field on oil-water properties. The degree of influence of three factors, namely sodium chloride solution concentration (C), direct current voltage (V), and voltage action time (t), on interfacial tension is studied. Gas chromatography, four component analysis, and Fourier transform infrared spectroscopy are combined to discuss the mechanism of the influence of changes in solution pH, crude oil components, and oil phase functional groups on interfacial tension. The results show that an external electric field can effectively reduce the interfacial tension between oil and water, and the maximum change in interfacial tension after the experiment can be reduced from 23.21 mN/m to 0.37 mN/m; Through range analysis, it can be concluded that the concentration of sodium chloride solution has the greatest impact on interfacial tension, followed by DC voltage and voltage action time. The optimal experimental conditions are 0.5 mol/L sodium chloride solution, 10 V DC voltage, and a voltage action time of 18 h, and the change in interfacial tension is related to the increase in pH value. The change in crude oil composition is also an important reason for the decrease in interfacial tension under external electric fields. Finally, Fourier transform infrared spectroscopy was used to determine that under the action of an electric field, the increase in pH of the sodium chloride solution resulted in the formation of carboxylate salts through chemical reactions between alkaline substances of solution and acidic substances of the oil, which were the key factors in reducing interfacial tension. This study helps to understand and explore the principles and mechanisms of Electrical-enhanced oil recovery in improving oil recovery, with the aim of contributing to the development and promotion of Electrical-enhanced oil recovery technology.

Polycyclic Aromatic Hydrocarbons Contamination and Quality of Locally Produced Crude Palm Oil in South-South Zone, Nigeria

Background: Oil palm, Elaeis guineensis Jacq is a perennial crop mainly cultivated for its vegetable oil. The fatty acid composition of crude palm oil (CPO) is mostly composed of palmitic, stearic oleic, and linoleic acids. Objectives: This study evaluated the quality of locally produced CPO from six states of South-South zone, Nigeria. Methods: The parameters of CPOs were characterized by specific gravity (SG), acid value (AV), percentage of free fatty acid (%FFA), and saponification value (SV) and peroxide value (PV). Polycyclic aromatic hydrocarbons (PAHs) in CPO were quantified using standard procedures, the related risk due to daily consumption of 25 g was characterized by lifetime cancer risk (LCR) and margin of exposure (MOE). Results: The study observed that the mean values of the parameters were 0.931 SG; 5.01 mgKOH g-1 AV; 2.28% FFA; 177.27 mgKOH g-1 SV and 29.65 meqO2 kg-1 PV. Apart from %FFA, the others did not meet the requirements recommended by the Codex Alimentarius Commission of the joint WHO/FAO. Diagnostic ratios of PAHs suggested a mixture of petrogenic and pyrogenic origins. The MOEs showed low health concern while 16PAH-LCR values which ranged from 2.48E-04 - 4.48E-04 were unacceptable. The screening value 0.003 was significantly (p> 0.05) lower than the computed total BaP equivalent (BaPeq) values indicating potential human health concerns. It is recommended that CPO processing and storage methods should be properly monitored to prevent quality reduction and contamination, which might have adverse effect on consumers.

Wettability of Different Mineral Surfaces in Supercritical CO2 Extraction: Interpretations from the Molecular Composition of Crude Oil

Wettability of Different Mineral Surfaces in Supercritical CO₂ Extraction: Interpretations from the Molecular Composition of Crude Oil

Effect of Ultrasonic Treatment on the Properties and Composition of High-Wax Crude Oil and Its Precipitates

Effect of Ultrasonic Treatment on the Properties and Composition of High-Wax Crude Oil and Its Precipitates

Low-Salinity Waterflooding for EOR in Field A of Western Offshore Basin: A Pilot Study Analysis with Laboratory and Simulation Studies—Early Observations

Carbonate reservoirs hold vast oil reserves, but their complex properties make traditional enhanced oil recovery (EOR) methods challenging. This study explores the application of low-salinity water flooding (LSWF) as a novel EOR method for India’s largest offshore carbonate oil field. Conventional EOR techniques were deemed unsuitable due to reservoir heterogeneity, pressure decline, high temperature, and the offshore location. Favorable factors for LSWF included successful seawater flooding history, medium-weight crude oil, and existing infrastructure. Following core flooding experiments demonstrating a 6–16% increase in oil recovery, a multi-pronged evaluation process was implemented. Single-well chemical tracer tests (SWCTT) and reservoir simulations confirmed the potential of LSWF. A specific target area was chosen based on reservoir characteristics, production data, and available facilities. Simulations predicted a 1.5% incremental oil recovery using diluted seawater (25% salinity) at 30% pore volume injection. After a positive techno-economic analysis, the first offshore LSWF project in India was completed within 3 years. Initial monitoring results are encouraging. This study highlights the successful journey of LSWF from concept to field deployment in a challenging carbonate reservoir, showcasing its potential for revitalizing such fields. Furthermore, this work provides valuable data relevant to Indian offshore environments, where factors like salinity, mineralogy, and crude oil composition pose unique challenges compared to other LSWF applications. These detailed data fill a critical gap in the existing literature.

Differential degradation of petroleum hydrocarbons by Shewanella putrefaciens under aerobic and anaerobic conditions.

The complexity of crude oil composition, combined with the fluctuating oxygen level in contaminated environments, poses challenges for the bioremediation of oil pollutants, because of compound-specific microbial degradation of petroleum hydrocarbons under certain conditions. As a result, facultative bacteria capable of breaking down petroleum hydrocarbons under both aerobic and anaerobic conditions are presumably effective, however, this hypothesis has not been directly tested. In the current investigation, Shewanella putrefaciens CN32, a facultative anaerobic bacterium, was used to degrade petroleum hydrocarbons aerobically (using O2 as an electron acceptor) and anaerobically (using Fe(III) as an electron acceptor). Under aerobic conditions, CN32 degraded more saturates (65.65 ± 0.01%) than aromatics (43.86 ± 0.03%), with the following order of degradation: dibenzofurans > n-alkanes > biphenyls > fluorenes > naphthalenes > alkylcyclohexanes > dibenzothiophenes > phenanthrenes. In contrast, under anaerobic conditions, CN32 exhibited a higher degradation of aromatics (53.94 ± 0.02%) than saturates (23.36 ± 0.01%), with the following order of degradation: dibenzofurans > fluorenes > biphenyls > naphthalenes > dibenzothiophenes > phenanthrenes > n-alkanes > alkylcyclohexanes. The upregulation of 4-hydroxy-3-polyprenylbenzoate decarboxylase (ubiD), which plays a crucial role in breaking down resistant aromatic compounds, was correlated with the anaerobic degradation of aromatics. At the molecular level, CN32 exhibited a higher efficiency in degrading n-alkanes with low and high carbon numbers relative to those with medium carbon chain lengths. In addition, the degradation of polycyclic aromatic hydrocarbons (PAHs) under both aerobic and anaerobic conditions became increasingly difficult with increased numbers of benzene rings and methyl groups. This study offers a potential solution for the development of targeted remediation of pollutants under oscillating redox conditions.

SYNTHESIS, SPECTROPHOTOMETRIC AND CHROMATOGRAPHY TECHNIQUES OF CRUDE OIL AND PETROLEUM PRODUCTS

Crude oil and petroleum products are important natural resources that have significant economic and environmental implications. Crude oil is a complex mixture of hydrocarbons that is extracted from the ground and refined to produce various petroleum products, including gasoline, diesel, and jet fuel. The composition of crude oil and petroleum products can vary widely depending on the source and the refining process used. Accurate characterization of these substances is essential for evaluating their quality, properties

Interactions between chloride-based salts (CaCl2 and MgCl2), ionic liquids, pH, and titanium oxide nanoparticles under low and high salinity conditions, and synthetic resinous crude oil: dorud oilfield

AbstractUnfortunately, oil reservoirs are complex considering the fluids (e.g., crude oil composition) and rock properties making it hard to propose a simple enhanced oil recovery (EOR) method for higher oil production. Besides, most of the investigations had focused on crude oil which is a complex mixture of thousands of components making it hard to extract any reliable conclusions with respect to the crude oil type. So, the current study is focused on the application of ionic liquids from different families of pyridinium and imidazolium, titanium oxide nanoparticles, and salts (MgCl2 and CaCl2) in the presence of resinous synthetic oil for the first time. The obtained results using the central composite design (CCD) approach revealed the positive effect of resin fraction on the IFT reduction by 27% considering the initial value (34.9%). Using the CCD approach revealed that using pH = 7, MgCl2 concentration = 21,000 ppm, CaCl2 concentration = 21,000 ppm, resin fraction of 9wt%t and 500 ppm of [C12mim][Cl] concentration reduces the IFT to minimum value of 0.62 mN/m while the minimum IFT value for optimum conditions of solution includes [C12py][Cl] led to minimum IFT value of 2.2 mN/m. But, the contact angle measurements revealed better synergy between [C12py][Cl] and TiO2-NPs (0–200 ppm) for better wettability alteration toward water-wet condition (27.3°) than [C12mim][Cl] (33.2°). Moreover, the IFT measurements revealed that the presence of TiO2-NPs is effective in reducing the IFT of the optimum formulations to 0.55 and 0.84 mN/m for [C12mim][Cl], and [C12py][Cl], respectively. According to the results, it seems that the obtained optimum formulations for [C12mim][Cl], and [C12py][Cl] are applicable for EOR purposes as new hybrid solutions.

Molecular and Carbon Isotopic Compositions of Crude Oils from the Kekeya Area of the Southwest Depression, Tarim Basin: Implications for Oil Groups and Effective Sources

Molecular and stable carbon isotopic compositions of 32 crude oils from the Kekeya area of the Southwest Depression, Tarim Basin, were analyzed comprehensively to clarify oil groups and trace oil sources. The results indicate that lacustrine shale sequences within the Upper-Middle Permian Pusige Formation (P3–2p) are the major effective oil sources; the thermal maturation effects exert the crucial impact on geochemical compositions of crude oils. In the Kekeya structural belt, crude oils produced from the Lower-Neogene, Middle-Paleogene and Middle-Cretaceous sandstone reservoirs were generated mainly from deeply buried P3–2p at the late-to-high maturity stage. These condensates are depleted in terpanes, steranes and triaromatic steranes and enriched in adamantanes and diamantanes. The evaluated thermal maturity levels of crude oils by terpanoids and steranes are generally lower than that of diamondoids, implying at least two phases of oil charging. In the Fusha structural belt, oils produced from the Lower-Jurassic reservoirs (J1s) of Well FS8 were generated from the local P3–2p at the middle to late mature stage. On the contrary, these oils are relatively rich in molecular biomarkers such as terpanes and steranes and depleted in diamondoids with only adamantanes detectable. The P3–2p-associated oils can migrate laterally from the Kekeya to Fusha structural belt, but not to the location of Well FS8. The Middle-Lower Jurassic (J1–2) lacustrine shales as the major oil sources are limited to the area around Well KS101 in the Kekeya structural belt. Crude oils originated from J1–2 and P3–2p can mix together within the Cretaceous reservoirs of Well KS101 by presenting the concurrence of high concentrations of terpane and sterane biomarkers and diamondoids as well as 2–4% 13C-enriched n-alkanes than those of P3–2p derived oils. This study provides a better understanding of hydrocarbon sources and accumulation mechanisms and hence petroleum exploration in this region.

Exploring wettability variations on minerals surfaces: Insights from spreading coefficient and interaction energy analysis

The wettability of minerals plays a pivotal role in determining the distribution of residual oil and devising effective flooding strategies for enhanced oil recovery. Utilizing molecular dynamics simulations, we investigated the surface wettability of various typical minerals. The simulation results illustrate that the modeled crude oil spreads completely on most mineral surfaces. We proposed an efficient approach to calculate the spreading coefficient of the modeled crude oil on mineral surfaces, yielding accurate predictions of the spreading state — whether it is completely spread or not. Compared with the conventional spreading simulation method, our approach offers significant time savings in the calculations. Additionally, our findings underscore the influence of various crude oil components on mineral surface wettability, emphasizing the crucial role of microscopic interactions between these components and the mineral. These insights contribute to a refined understanding of mineral surface wettability and its correlation with crude oil composition, offering valuable guidance for optimizing reservoir management and production strategies.

Effect of different degumming methods on the chemical composition and physicochemical properties of tiger nut (Cyperus esculentus L.) oil

Abstract Objectives Tiger nut (Cyperus esculentus L.) oil is a promising edible oil that is rich in oleic acid. This study aimed to clarify the impact of different degumming methods on the chemical composition and physicochemical properties of crude tiger nut oil (CTO). Materials and Methods Five degummed tiger nut oils were prepared by high-temperature water (HWDO), medium-temperature water (MWDO), sodium chloride solution (SDO), acidic solution (ADO), and enzymatic method (EDO), respectively. Results Compared to that of CTO, the phospholipid contents of HWDO, MWDO, SDO, ADO, and EDO were reduced by 99.39%, 97.18%, 69.95%, 63.77%, and 65.60%, respectively. For CTO and all degummed oils, the fatty acid and endogenous antioxidant (i.e. tocopherols, sterols, flavonoids, total phenolics, and carotenoids) contents showed only small differences, but showed significant differences in quality parameters. Both the oxidative stability index and ferric ion-reducing antioxidant power decreased significantly after degumming; the former decreased from 52.26 to 15.55–19.80 h, and the latter decreased from 5818.91 to 4348.73–4524.34 μmol Trolox (TE)/kg. Conclusions These changes are highly related to the removal of hydratable phospholipids. In short, EDO exhibited the lowest turbidity, whereas MWDO showed the best oxidative stability (19.80 h) and highest smoke point (230.0 °C). This information can be utilized to improve the industrial production of tiger nut oil.

ANALYSIS OF EXISTING CALCULATION METHODS FOR PREDICTING PARAFFIN PRECIPITATION AND DETERMINATION OF CRITICAL PARAMETERS

pecially during the production, transportation and refining of crude oil. This problem is related to changes in temperature and pressure, crude oil composition, and flow conditions. Research in the petroleum industry is actively focused on developing improved models and correlations to accurately predict wax deposition. The authors of the paper consider approaches based on thermodynamic principles to develop a model capable of predicting the conditions under which wax deposition occurs. The model takes into account the chemical and physical interactions in the system, and also includes parameters determined from laboratory experiments and data on the characteristics of crude oil. This article presents an analysis of scientific research literature and publications on calculation methods for predicting paraffin precipitation, and a comparative analysis of existing current correlations is carried out. Also shown is the calculation of the critical parameters (PVT) from the obtained data, which is the first step towards a model for calculating the precipitated wax.

Enzyme-assisted aqueous extraction of fish oil from Baltic herring (Clupea harengus membras) with special reference to emulsion-formation, extraction efficiency, and composition of crude oil.

Enzyme-assisted aqueous extraction (EAAE) is a green, and scalable method to produce oil and protein hydrolysates from fish. This study investigated the role of different parameters on emulsion formation, oil recovery, and the composition of crude oil during EAAE of Baltic herring (Clupea harengus membras). Fatty acid compositions, lipid classes, tocopherols, and oxidation status of the EAAE crude oils were studied. Compared to solvent-extracted oil, EAAE resulted in a lower content of phospholipids accompanied by a 57% decrease in docosahexaenoic acid. Changing fish to water ratio from 1:1 to 2:1 (w/w) with ethanol addition led to the greatest reduction (72%) of emulsion, which resulted in an increase in oil recovery by 11%. The addition of ethanol alone, or reduction of enzyme concentration from 0.4% to 0.1% also reduced emulsion-formation significantly. Overall, emulsion reduction resulted in higher content of triacylglycerols and n-3 polyunsaturated fatty acids in the crude oil extracted.

EVALUACIÓN DE UNA UNIDAD HPHT ACOPLADA CON SONDA NIR PARA DETERMINAR EL INICIO DE LA PRECIPITACIÓN DE ASFALTENOS BAJO DIFERENTES PRESIONES

Asphaltenes are characterized as the crude oil fraction with the highest molar mass and polarity, presetting mainly (poly) aromatic groups. The flocculation and deposition of asphaltenes causes large losses to the oil industry. Understanding the phase behavior of asphaltenes under conditions closer to those found in reservoirs is important. Therefore, LMCP/UFRJ started operating a high-pressure high-temperature (HPHT) unit coupled to a near-infrared spectrometer probe that can use different flocculants. This work describes the development of a procedure as well as the validation of the results obtained from this unit. Due to the complex composition of crude oil, model systems (MS) were prepared with asphaltenes extracted with n-pentane (C5I) and n-heptane (C7I). The experiments were carried out at atmospheric pressure, titrated with n-heptane, and at 100 and 300 bar titrated with propane. As expected, C7I asphaltenes were more unstable, presenting lower precipitation onset than C5I asphaltenes under ambient conditions and higher pressures. However, for both MS, the stability increased with rising pressure when using propane as a solvent. The proposed method to evaluate asphaltenes precipitation onset was effective for MS in toluene and dead crude oil, and is a promising alternative for investigation of different types of crude oil.