Heavy Crude Oil Components Research Articles

Study on the influence mechanism of the interaction between waxes and asphaltenes on hydrate growth

Study on the influence mechanism of the interaction between waxes and asphaltenes on hydrate growth

A comprehensive review on the significant tools of asphaltene investigation. Analysis and characterization techniques and computational methods

After years of research into the heavy components of crude oil, asphaltenes are still one of the most complex and unknown organic molecules. During these years, asphaltene has been the subject of research by chemists, chemical engineers, petroleum engineers, materials engineers and other sciences from various angles. Abstract of research on asphaltenes is a decoding of their molecular structures which is the key to solving the puzzle of predicting the specific properties of asphaltenes, such as self-association, deposition, and surface activity in crude oil. In this regard, a variety of laboratory techniques have been used to identify asphaltenes in the field of the molecular weight, chemical structure, architecture and physico-chemical properties such as MASS, UV-VIS, NMR, EPR, ESR, FL, IR, RA, XPS, UL, XRD, SAS, GC, AFM, STM, TEM and etc. In parallel with molecular characterization research, engineers in this field have made great efforts to predict the properties of asphaltenes to prevent the economic damage caused by the deposition and formation of w/o emulsions in the production cycle (Oil well reservoir, production, transmission, storage, refinery, etc.). Numerous modeling and simulation methods have been used to investigate these topics. In this article, a comprehensive review of laboratory techniques for the identification of asphaltene molecules with a brief introduction of these techniques and the most popular and most practical computational models for predicting the properties of asphaltene based on Solubility theory and colloidal theory Has been introduced. Also Recent molecular simulation methods for the study of asphaltenes, such as Monte Carlo and especially molecular dynamics (MD) and useful tools for the study of asphaltene have been reviewed. • A list of the most important techniques used to identify asphaltene molecules has been prepared along with a summary of the method. • Two theories, solubility and colloidal are more popular for predicting the deposition of asphaltene in oil. • MD is one of the suitable methods to study the physicochemical properties of materials such as asphaltenes at the nanoscale.

Experimental studies on reaction laws during the process of air injection into the oil reservoirs with low permeability

The low permeability oil reservoirs are widely distributed in the world, but difficult to develop with the traditional methods due to the low permeability and poor injection properties. Air injection technique not only has the common characteristics of other gas injection techniques, but also can improve the quality of crude oil in situ because of the oxidative ability of the injected air, with a unique advantage in developing low permeability reservoirs. In order to study the reaction regularity between the hydrocarbon components in crude oil under different conditions with the oxygen in the injected air, this experiment is designed for a low permeability sandstone reservoir. In this experiment, one set of self-designed static low-temperature oxidation equipment (including injection pump and high-temperature high–pressure reactor with sampling outlets) has been used. Through analysis of the results of the chromatography for over 60 oil and gas samples, conclusions can be made that after low temperature oxidation (LTO) reactions between the crude oil and the oxygen in the injected air, the concentration of the heavy components in crude oil decreased, and the concentration of the light components increased. By injecting oxygen-reduced air with 8% of oxygen, the concentration of the heavy components of crude oil in the target reservoir reduced most obviously. The formation water and associated gas can hinder the pyrolysis of heavy components, while the minerals in the formation can accelerate the pyrolysis process. The relationship between the carbon atoms number in each of the most consumed hydrocarbon molecule and different LTO reaction conditions has been proposed. According to the sensitivity analysis, it is believed that the influence of the formation water on the LTO reactions is greater than that of minerals in the formation, and influence of associated gas is less than that of minerals. Finally, combined the related physical and chemical theories, a LTO chemical reaction equation has been put forward for the targeted low permeability oil reservoir. The conclusions of the studies can provide some references for the indoor experiments and field applications of air injection in the future.

Green Technology for Remediation of Water Polluted with Petroleum Crude Oil: Using of Eichhornia crassipes (Mart.) Solms Combined with Magnetic Nanoparticles Capped with Myrrh Resources of Saudi Arabia.

Crude oil pollution of water bodies is a worldwide problem that affects water ecosystems and is detrimental to human health and the diversity of living organisms. The objective of this study was to assess the ability of water hyacinth (Eichhornia crassipes (Mart.) Solms) combined with the presence of magnetic nanoparticles capped with natural products based on Myrrh to treat fresh water contaminated by crude petroleum oil. Magnetic nanoparticles based on magnetite capped with Myrrh extracts were prepared, characterized, and used to adsorb heavy components of the crude oil. The hydrophobic hexane and ether Myrrh extracts were isolated and used as capping for magnetite nanoparticles. The chemical structures, morphologies, particle sizes, and magnetic characteristics of the magnetic nanoparticles were investigated. The adsorption efficiencies of the magnetic nanoparticles show a greater efficiency to adsorb more than 95% of the heavy crude oil components. Offsets of Water hyacinth were raised in bowls containing Nile River fresh water under open greenhouse conditions, and subjected to varying crude oil contamination treatments of 0.5, 1, 2, 3, and 5 mL/L for one month. Plants were harvested and separated into shoots and roots, oven dried at 65 °C, and grounded into powder for further analysis of sulphur and total aromatic and saturated hydrocarbons, as well as individual aromatic constituents. The pigments of chlorophylls and carotenoids were measured spectrophotometrically in fresh plant leaves. The results indicated that the bioaccumulation of sulphur in plant tissues increased with the increased level of oil contamination. Water analysis showed significant reduction in polyaromatic hydrocarbons. The increase of crude oil contamination resulted in a decrease of chlorophylls and carotenoid content of the plant tissues. The results indicate that the water hyacinth can be used for remediation of water slightly polluted by crude petroleum oil. The presence of magnetite nanoparticles capped with Myrrh resources improved the remediation of water highly polluted by petroleum crude oil.

Application of Bacillus spp. in Pilot Test of Microbial Huff and Puff to Improve Heavy Oil Recovery

Microbial metabolic products, such as biosurfactants, bioemulsifiers, acids, solvents, and biogases, are useful for reducing the viscosity of heavy oils and enhancing oil recovery. Two heavy oil viscosity-reducing microorganisms, namely, SH-2 and SH-3, were selected from produced water which were collected from high-temperature reservoirs by enrichment culture technique. The screened bacteria produce biosurfactants and biogases that can biodegrade heavy crude oil components. The screened bacteria combined with indigenous bacteria were applied in a pilot test of microbial huff and puff. Temperature, porosity, and permeability of the reservoir were 50 °C, 14.32%, and 22 mD, respectively. After microbial treatment, the 50 °C degassing for crude oil viscosity of the produced oil was decreased from 750 to 634 mPa·s. Moreover, wax and resin–asphaltene contents of produced oil were reduced by 12.3% and 16.9%, respectively. The average oil production was improved from 2.2 to 3.5 t/day after microbial treatment. T...

Axial dispersion modeling of industrial hydrocracking unit and its multiobjective optimization

Hydrocracking is one of the most important refining operations used to crack heavy crude oil components into valuable lighter products. It processes less expensive, difficult to crack heavy feedstock to produce low sulfur and low aromatics content hydrocarbon fuels. In this study, a two-stage industrial hydrocracker is modeled using axial dispersion model to incorporate the mixing effects of feed flow. A 25-lump kinetics is used to simulate and validate the plant data. This validated model is then used for three-objective optimization in which the yields of aviation turbine fuel (ATF) and diesel are maximized simultaneously with minimization of the total amount of hydrogen required in a process cycle using a real-coded elitist non-dominated sorting genetic algorithm (RNSGA-II). The Pareto optimal results obtained show the 26% reduction in total amount of hydrogen required in a process cycle, with nearly same diesel and marginally low ATF production compared to plant data.

Characterization and optimization of biosurfactants produced by Acinetobacter baylyi ZJ2 isolated from crude oil-contaminated soil sample toward microbial enhanced oil recovery applications

Abstract The present work aims to investigate the surface activity of the biosurfactant produced by Acinetobacter baylyi ZJ2 isolated from crude oil-contaminated soil sample in China and evaluate its potential application in microbial enhanced oil recovery. The biosurfactant produced by A. baylyi ZJ2 was identified as lipopeptide based on thin-layer chromatography, Fourier transform infrared spectroscopy and nuclear magnetic resonance techniques. This biosurfactant could reduce the surface tension of water from 65 mN/m to 35 mN/m, and interfacial tension against oil from 45 mN/m to 15 mN/m. Moreover, surface activity stability results showed that this biosurfactant was effective when the salinity was lower than 8% and the pH value was 4–9, and it was especially stable when the salinity was lower than 4% and pH was 6–7. Based on the result of gas chromatography, there was a decrease in heavy components and an increase in light components, which indicated that A. baylyi ZJ2 exhibited the biodegradability on the heavy components of crude oil. Furthermore, the ability of recovering oil from oil-saturated core showed that nearly 28% additional residual oil was displaced after water flooding. The lipopeptide biosurfactant produced by A. baylyi ZJ2 presented a great potential application in microbial enhanced oil recovery process, owing its good surface activity and satisfying degradation ability to crude oil.

Investigation of Biosurfactant-Producing Indigenous Microorganisms that Enhance Residue Oil Recovery in an Oil Reservoir After Polymer Flooding

Three biosurfactant-producing indigenous microorganisms (XDS1, XDS2, XDS3) were isolated from a petroleum reservoir in the Daqing Oilfield (China) after polymer flooding. Their metabolic, biochemical, and oil-degradation characteristics, as well as their oil displacement in the core were studied. These indigenous microorganisms were identified as short rod bacillus bacteria with white color, round shape, a protruding structure, and a rough surface. Strains have peritrichous flagella, are able to produce endospores, are sporangia, and are clearly swollen and terminal. Bacterial cultures show that the oil-spreading values of the fermentation fluid containing all three strains are more than 4.5 cm (diameter) with an approximate 25 mN/m surface tension. The hydrocarbon degradation rates of each of the three strains exceeded 50%, with the highest achieving 84%. Several oil recovery agents were produced following degradation. At the same time, the heavy components of crude oil were degraded into light components, and their flow characteristics were also improved. The surface tension and viscosity of the crude oil decreased after being treated by the three strains of microorganisms. The core-flooding tests showed that the incremental oil recoveries were 4.89-6.96%. Thus, XDS123 treatment may represent a viable method for microbial-enhanced oil recovery.

Gas Chromatographic Analysis of Crude Oils with Thermal Extraction Sampling

A novel experimental technique has been developed for the gas chromatographic (GC) analysis of crude oils. The injection of the samples is carried out using a thermal extraction device, directly connected to the GC. Crude oil samples are initially adsorbed on a suitable material and subsequently their light components are thermally extracted and driven into the GC by the carrier gas flow, while the heavy end remains adsorbed on the sample probe. Factors affecting the depth of the analysis, such as the kind of adsorbent material, temperature, and duration of sampling, were studied. The main advantage of the proposed technique is that no preliminary separation of the crude oil sample into a light and heavy fraction is needed prior to the GC analysis. In addition, the contamination of the chromatographic system by the heavy crude oil components is avoided.

Particle-stabilized emulsions: Effect of heavy crude oil components pre-adsorbed onto stabilizing solids

Model emulsions stabilized by means of silica nanoparticles have been investigated. The effect of the modification of the particle surface has been monitored using infrared (IR) spectroscopy, contact angle measurements and zeta potential measurements. It is shown how coating of the nanoparticles with asphaltenes and resins will modify the stabilization profile compared to that obtained with no coating. The stabilization efficiency was greatly enhanced by adsorption of crude oil components onto very hydrophilic or very hydrophobic silica. Possible stabilization mechanisms have been discussed. We have demonstrated catastrophic phase inversion of emulsions stabilized by particles with intermediate wetting properties, induced by simply increasing the volume of the disperse phase. In all cases, the stability to gravitational induced separation (coalescence) passes through a minimum approaching inversion in line with a maximum in drop size of the disperse phase. Transitional phase inversion from o/w to w/o emulsion type can be achieved by modifying of the hydrophilicity of the particles, either by silylation or by a controlled coating with heavy components from crude oil. The relevance of this study for real petroleum systems is discussed.

CHARACTERIZATION AND MULTIPHASE EQUILIBRIUM PREDICTION OF CRUDE OIL HEAVY COMPONENTS

For compositional simulation purposes, a new method has been developed for estimating the specific gravities of pseudo-components that are required to characterize the heavy components of crude oil...