Chemical Composition Of Crude Oil Research Articles

Predictive Petroleomics: Measurement of the Total Acid Number by Electrospray Fourier Transform Mass Spectrometry and Chemometric Analysis

Crude oil samples are uniquely complex because of the number of compounds present that can only be resolved using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The FT-ICR MS technique has been redefined for examining the composition of crude oil and its products, which has led to a new field called “petroleomics”. The chemical composition ultimately determines the chemical and physical properties and the behavior of petroleum and its products. “Petroleomics” predicts the properties and behavior of petroleum using its composition to solve production and processing problems. This paper correlates the chemical composition of crude oil with the total acid number (TAN), which enables the development of prediction models using partial least squares (PLS) and support vector machines (SVMs) as alternative multivariate calibration methods that allow for the application of FT-ICR MS analysis in direct measurements. The prediction models using PLS and SVM demonstrated low prediction errors and superior performance in relation to the univariate method. These results support the development of robust models to predict crude oil properties based on the vast quantity of information provided by FT-ICR MS using PLS and SVM as multivariate calibration procedures.

Empirical and Correlative Study of PVT Proprieties of Algerian Oil

The knowledge of the Pressure - Volume - Temperature (PVT) parameters is of an major importance in calculations of the properties of the fluids and the development of the layers, namely, the determination of the bubble pressures (Pb) and the factor of volume of oil formation (Bo), the design of the treatment units of the fluids and the estimate of the volumetric characteristics in the oil tanks.In absence of PVT data, the use of the correlations is capital for the prediction of PVT properties, thus the properties associated. Sight the geological effect, which represents the modification of the chemical composition of crude oil from one area to another, it is difficult to obtain such a precise result thanks to empiricisms, from this point of view, correlations PVT must be studied and modified according to the regional characteristics of oils.The development of correlations PVT was the scientific research task object many, which contributed to a great number of publications in differing, re-examined. Several graphic correlations (in the form of abacus) and mathematics are developed during two last decades to determine, in particular, Pb and Bo. These correlations are primarily based on the assumption that Pb and Bo are in functions direct with the rate of gas-oil solution (Rs), the temperature of tank (Tf), the specific gravity of gas (γg), and the specific oil gravity (γo). Moreover, the success of such a correlation depends mainly on the beach of the experimental data at which it was developed, as well as the geographical area.

Effect of the chemical composition of crude oil and water cut on the amount of asphaltene-resin-paraffin deposits

The chemical composition of crude oils from five fields of Volgograd oblast has been studied. It has been shown that predicting the low-temperature properties of oil and for selecting asphaltene-resin-paraffin deposition inhibitors requires a more profound knowledge of the hydrocarbon composition of oil in addition to the structural-group composition. The presence of produced water in the produced well fluid increases the amount of asphaltene-resin-paraffin deposits.

Geographical classification of weathered crude oil samples with unsupervised self-organizing maps and a consensus criterion

Weathering processes considerably change the chemical composition of crude oils spilled on the environment. The impact of this effect on the classification capabilities of Kohonen neural networks (self-organizing maps, SOM) trained to predict the geographical origin of crude oils, was studied. A set of 38 worldwide crude oils from six distinct geographical regions was considered and each product was weathered to build a database of 263 samples. Gas Chromatography–Mass Spectrometry was used to monitor weathering and to determine a suite of 22 ratios of PAHs (polycyclic aromatic hydrocarbons) and alkanes, which are currently considered resilient to weathering. Three different experiments were performed with SOMs to study the effect of oil weathering and analytical conditions on the final results: a) weathered and un-weathered samples were randomly distributed in the training and validation sets, b) the training set included only unweathered samples while the validation set consisted of all the weathered samples, and c) the operational conditions (instruments/technicians) were different for the samples of the training and validation sets. After training the different SOMs, the percentage of correct classifications was in the 83.8%–95.7% range for the validation sets. A consensus SOM associated to a confidence level is proposed in which the decision is taken based on the number of votes of the winning class. The lowest success on the classification of the most weathered samples was expected and can be explained easily by the important changes on the chromatographic profiles due to the disappearance of the lightest alkanes and the relative enrichment on the more substituted PAHs. Most incorrect classifications occurred because the samples activated neurons at the close neighbourhood of the regions where they should belong to. The ‘consensus’ approach improved the capability to predict unknown samples. Results were compared to those from discriminant partial least squares and a variable selection step before the development of the SOMs was investigated.

Frequency Domain Fluorescence Lifetime Study of Crude Petroleum Oils

Frequency domain (FD) fluorescence lifetime data was collected for a series of 20 crude petroleum oils using a 405 nm excitation source and over a spectral range of approximately 426 to approximately 650 nm. Average fluorescence lifetimes were calculated using three different models: discrete multi-exponential, Gaussian distribution, and Lorentzian distribution. Fitting the data to extract accurate average lifetimes using the various models proved easier and less time consuming for the FD data than with Time Correlated Single Photon Counting (TCSPC) methods however the analysis of confidence intervals to the computed average lifetimes proved cumbersome for both methods. The uncertainty in the average lifetime was generally larger for the discrete lifetime multi-exponential model when compared to the distribution-based models. For the lifetime distributions, the data from the light crude oils with long lifetimes generally fit to a single decay term. Heavier oils with shorter lifetimes required multiple decay terms. The actual value for the average lifetime is more dependant on the specific fitting model employed than the data acquisition method used. Correlations between average fluorescence lifetimes and physical and chemical parameters of the crude oils were made with a view to developing a quantitative model for predicting the gross chemical composition of crude oils. It was found that there was no significant benefit gained by using FD over TCSPC other than more rapid data analysis in the FD case. For the FD data the Gaussian distribution model for fluorescence lifetime gave the best correlations with chemical composition allowing a qualitative correlation to some bulk oil parameters.

Conversion and degradation of crude oil by Bacillus SP3

The objective of this study is to demonstrate the basic characteristics of Bacillus SP3 and evaluate its effect on different crude oils. Strain SP3 is a motile, gram-positive, spore-producing rod that was isolated from a reservoir of the Shengli oil field in East China. The cells of strain SP3 grew at high temperatures up to 58°C at the pH range of 5.5–8.5. Strain SP3 grew facultatively and could use different organic substrates, and produce some metabolites such as 4-hydroxy-4-methyl-2-pentanone, methyl-2-nitrogen benzene and 1, 2-benzenedicarboxylic acid bis ester. Laboratory studies have demonstrated that the strain converted and degraded different components and changed the physical and chemical properties of crude oils. Strain SP3 degraded crude oil and the growth of bacteria on crude oil resulted in loss of aromatic hydrocarbons, resins and asphaltenes. The bioconversion of crude oils would lead to an enrichment in lighter hydrocarbons and an overall redistribution of saturate hydrocarbons. The interactions of microorganisms with crude oils are variable, depending on the microbial species and the chemical compositions of crude oils.

Fault-fracture mesh petroleum plays in the Zhanhua Depression, Bohai Bay Basin: Part 2. Oil-source correlation and secondary migration mechanisms

The chemical compositions of crude oils from over 20 oilfields in the Zhanhua Depression, Bohai Bay Basin, were studied in order to understand their genetic relationships, thermal maturity and biodegradation ranking. Molecular geochemical parameters indicate the presence of three possible oil families in reservoirs ranging from Paleozoic (basement) to Neogene. A number of biomarker features support deposition of the source rocks for these oils under a wide range of depositional environments. The majority of the oils discovered in the depression belong to the FL family, and display characteristics consistent with a dominantly freshwater (to slightly brackish water) lacustrine source rock in the Es 3 member of the Shahejie Formation. The somewhat geographically restricted SL family oils are apparently linked to saline lacustrine, carbonate-evaporite source rocks distributed mostly in the upper Es 4 member of the Shahejie Formation from the Bonan-Gubei sag areas. The thermally less mature BL family oils occur mostly within the Es 1, Es 2 or Dongying Formation reservoirs near the central sag areas, and show close affinities to the interbedded or intercalating Es 1 calcareous mudstones and oil shales deposited in a slightly saline to dominantly brackish water lacustrine setting. The SL and FL family oils are generally mature, whereas most of the BL family oils usually show low maturity. Oil-source correlation demonstrates strong genetic relationships between the mature Es 4 and Es 3 source rocks of the Eocene–Oligocene Shahejie formation in the sag areas and the oils accumulated in the shallow Neogene petroleum plays. The geochemical data provide strong support for two sharply contrasting hydrocarbon migration scenarios: (1) short distance lateral migration is dominant in the central sag areas; and (2) the fault-fracture mesh facilitated vertical migration, and coupled with the regional porous Guantao Formation sand sheets, makes the structural, stratigraphic and lithological features over basement high blocks the focal points for petroleum accumulation. Therefore, further exploration in this highly mature petroleum province should focus on heavy oils in the shallow Neogene strata and light oils in the tight sandstones of the deep sag areas.

Effect on crude oil by thermophilic bacterium

The objective of this study is to demonstrate the basic characteristics of thermophilic strain TH-2 and evaluate the effect of strain TH-2 on different crude oils. Strain TH-2 is a non-motile, Gram-negative, oil-degrading thermophile that was isolated from a reservoir of the Shengli oil field in East China. The cells of strain TH-2 were grown at high temperatures up to 85 °C in the neutral to alkaline pH range. Depending on the culture conditions, the organisms occurred as single rods, or as filamentous aggregates. Strain TH-2 was grown chemoorganotrophically and produced volatile fatty acids and such surfactants as 1,2-benzenedicarboxylic acid-bis ester, dibutyl phthalate, and di- n-octyl phthalate. It could use different organic substrates (acetate, d-glucose, fructose, glycerol, maltose, pyruvate, starch, sucrose, and xylose). Laboratory studies have demonstrated that the strain affected different crude oils, converted and degraded various components and changed the physical and chemical properties of crude oils. The strain TH-2 degraded crude oil and growth of the bacterium on crude oil resulted in loss of aromatic hydrocarbons, resins, and asphaltenes. The bioconversion of crude oils leads to an enrichment in lighter hydrocarbons and an overall redistribution of these hydrocarbons. The interactions of microorganisms with crude oils are variable and depend on the microbial species and the chemical compositions of crude oils. Different interactions may influence the efficiency of processes in which single or mixed microbial species are used for the oil treatment and may also suggest possible combinations of biological and chemical technologies.

Bench-scale optimization of bioaugmentation strategies for treatment of soils contaminated with high molecular weight polyaromatic hydrocarbons

The chemical composition of crude oil and even of refined petroleum includes hundreds of different alkanes and aromatic hydrocarbons. Among these are the polycyclic aromatic hydrocarbons (PAHs), which are known carcinogens and widespread environmental contaminants. Some compounds present in hydrocarbon-contaminated soils are rapidly removed by the activities of autochthonous bacterial populations while other PAHs, especially those with four or more fused aromatic rings, are refractory to biodegradation. The persistence of high molecular weight polyaromatic hydrocarbons (hPAHs) in soils implies either that their low solubility renders them poorly available to bacteria, or that autochthonous bacteria do not contain the metabolic or co-metabolic pathways required for their degradation or both. The rate and extent of PAH degradation in contaminated soil is not always predictable for standard biological treatment strategies. This study examines a matrix of treatments suitable for land farming in order to identify those that maximize the removal of hPAHs. The treatments include those intended to increase the bioavailability of hPAH, such as additions of biosurfactant-producing bacteria (i.e. Pseudomonas aeruginosa #64) and addition of light oils, as well as treatments intended to increase the metabolic potential of the bacterial community. The latter includes the addition of inorganic nutrients and bacterial strains capable of degrading hPAHs co-metabolically (i.e. Sphingomonas paucimobilis EPA 505). The efficacy of immobilizing PAH-degrading bacteria on vermiculite is also considered, as will be the monitoring of leachate for biodegradation of PAHs in a simulated land farming operation.

Predictions of Water-in-crude Oil Emulsion Stability From Chromatographic Data

Abstract Following a recent method which aims to characterize solvents in terms of given solute-solvent molecular interactions, a general solvation linear free energy relationship (LSER) equation was devised by Abraham and used in gas chromatography with crude oils as stationary phases to calculate molecular interaction. terms According to these terms and to information relatedto the bottle test, a new decision model has been set up to predict the stability of water-in-crude oil emulsions. It requires two discriminant functions taking into account two interaction terms characterizing hydrogen bonds and polar interactions. Of the 24 crude oils selected from miscellaneous geographical and geological origins 80% were correctly classified in three categories related to emulsion stability. Therefore, this model permits us to estimate the stability of water-in-crude oil emulsions and provides knowledge, which can be used in the selection of optimal conditions for the oil recovery process. Introduction In the petroleum industry, emulsions of oil and water are one of the many problems encountered. These emulsions have widespread occurrence in petroleum recovery and they may be desirable or undesirable(l). So the evaluation of the stability of emulsion systems and the selection of optimal conditions for the oil recovery process must be closely scrutinized. Most of the crude oil emulsions formed in the oil field are of the water-in-oil type. They vary from one field to another and many scientific disciplines are involved in their study and treatment, but the fundamental explanation of this phenomenon is now well known. Emulsions are normally prepared by shaking two immiscible liquids like oil and water and usually some kind ofemulsifying agent has to be added to stabilize the product. Small droplets are then produced and the stability of these droplets depends upon a number of factors: the ratio of the phase volume, the mechanical shear forces, some physical parameters and the chemical composition. If the three first factors are fixed, then emulsion stability could be approached from different sides of the chemical composition. Regarding the molecules in a crude oil, two types of them could be distinguished to explain bulk viscosity properties and interfacial properties. Conventional analytical techniques and classical methods as separative, spectrometric, and statistical tools(2, 3) have been applied to correlate chemical composition of crude oils and their properties or behaviour in production(l, 4–6). But crude oils are very complex mixtures and chemical composition analysis is limited. Moreover, the importance of the amount of some chemical species in explaining the crude oils behaviour is different from one crude oil to another. So it seems to be more interesting to study molecular interactions rather than the chemical composition(7–9). To be more precise, the process of emulsification is governed by surface forces(l) which depends upon intermolecular forces. These forces have been classified in non specific forces (Keesom, Debye, and London) usually known as van der Waals forces and specific forces or hydrogen bonding.

Unusual crude oils in the Canadian Williston Basin, southeastern Saskatchewan

The Jedburgh well (location: 16-14-27-8W2) was drilled on a small salt dissolution structure in the Williston Basin. The well lies near the Cussed Creek structure, a complex feature involving both Phanerozoic faults that offset the Precambrian basement and the dissolution edge of the Middle Devonian Prairie Formation halite. The chemical compositions of crude oils recovered from cores of Devonian strata in this well are unique in the Williston Basin and unusual in a global perspective, because they contain significant quantities of α-olefins (with the n-C 17 alk-1-ene/alkane ratio ranging from 0.28 to 0.72). The gross chemical compositions and distributions of aliphatic biomarkers, aromatic hydrocarbons and pyrrolic nitrogen compounds in the oils indicate that they were generated by high-temperature, short-term pyrolysis of thermally immature organic matter. Their composition indicates that they were not generated in situ, but accumulated in the Jedburgh well after lateral migration from areas that were influenced by post-Devonian magmatic intrusions. The inferred migration distance (∼10 km) suggests that such intrusions occur within the Cussed Creek structure.

The use of chemical markers in the evaluation of crude oil bioconversion products, technology, and economic analysis

Experimental data gathered over the past several years show that the interactions of microorganisms with crude oils are variable and depend on the microbial species and the chemical composition of crude oils. Systematic studies of chemical mechanisms by which selected microorganisms react with crude oils have led to the identification of biochemical markers characteristic of the interactions of microbes with oils. These biomarkers belong to several groups of natural products ranging from saturate and polyaromatic hydrocarbons containing heterocyclics to organometallic compounds. Chemical marker analyses indicate that the interaction of microbes with crude oils involves multiple chemical reactions resulting from the biochemical interactions between microbes and oils. Different interactions may influence the efficiency of processes in which single or mixed microbial species are used for the oil treatment and may also suggest possible combinations of biological and chemical technologies. Further, the biochemical conversions of oils can be monitored by these chemical markers, which is particularly useful in the optimization of biochemical processing, cost efficiency, and engineering studies. Recent results from these studies will be discussed.

Numerical simulation of crude oil behaviour from chromatographic data

In the aim of predicting oil fields behaviour, petroleum industry attempts to quantify experimental behaviour. The usual determinations of these behaviour, which are difficult and time consuming, may be challenged by a more convenient and fast inverse gas chromatographic approach. Gas chromatographic retention data of selected test solutes are determined and coefficients (descriptors) of the LSER equation of Abraham et al. are calculated for 47 crude oils of different geographical and geological origins. The data set generated is in accord with chemical composition of crude oils. It is used to classify crude oils, to construct QSBR (Quantitative Structure Behavior Relationships) models to predict behaviour and is compared with crude oil polarity parameters. Thus descriptors resulting from applying a solvation model to gas chromatography could provide valuable information for optimisation of operations in oil industry.

95/03339 The significance of chemical markers in the bioprocessing of fossil fuels

Biochemical conversion of crude oils is a multi-step process proceeding through a series of biochemical reactions. These reactions can be characterized by a set of chemical markers which are associated with the chemical composition of crude oils. Reactions with heavy crude oils indicate that there is an overall decrease in the concentration and chemical speciation of organic sulfur compounds, and a redistribution of hydrocarbons and organometallic species. The contents of trace metals in the crude oils, such as nickel and vanadium, also decrease. Further, heavy ends of crudes, containing the asphaltenes and the polar nitrogen, sulfur, and oxygen containing fractions, as well as the organometallic compounds and complexes, are biochemically converted to lower molecular weight chemical species. In the studies reported in this paper, microorganisms used to mediate such reactions were thermophilic (>60{degrees}C) and pressure tolerant (up to 2500 psi). These organisms are also capable of biochemical conversion of bituminous and lignite coals in an analogous manner to their action on crude oils and follow similar trends characterized by chemical markers.

The significance of chemical markers in the bioprocessing of fossil fuels

Biochemical conversion of crude oils is a multi-step process proceeding through a series of biochemical reactions. These reactions can be characterized by a set of chemical markers which are associated with the chemical composition of crude oils. Reactions with heavy crude oils indicate that there is an overall decrease in the concentration and chemical speciation of organic sulfur compounds, and a redistribution of hydrocarbons and organometallic species. The contents of trace metals in the crude oils, such as nickel and vanadium, also decrease. Further, heavy ends of crudes, containing the asphaltenes and the polar nitrogen, sulfur, and oxygen containing fractions, as well as the organometallic compounds and complexes, are biochemically converted to lower molecular weight chemical species. In the studies reported in this paper, microorganisms used to mediate such reactions were thermophilic (> 60°C) and pressure tolerant (up to 2500 psi). These organisms are also capable of biochemical conversion of bituminous and lignite coals in an analogous manner to their action on crude oils and follow similar trends characterized by chemical markers. For example, X-ray absorption near-edge structural (XANES) analyses of biotreated crude oils and low grade coals show that biochemical reactions lead to decreases in organic sulfides and thiophenes with a concurrent increase in sulfoxide contents. Chemically related constituents present in heavy crude oil fractions and low grade coals are the asphaltenes. Asphaltenes are complex structures containing heteroatoms and metals involved in inter- and intra-molecular bridges and stereochemical configurations. The chemical markers associated with the biochemical conversion of oils and coals indicate multiple biochemical processes involving chemical reactions at sites containing heteroatoms and metals leading to a breakdown of the structure(s) to smaller molecular weight units. Thus, using chemical markers as diagnostic tools, the extent and the efficiency of fossil fuel bioconversion may be predicted and monitored, allowing for better cost-efficient field trials. Recent results in this area will be presented and discussed in this paper.

Relationships in component-fractional and chemical composition of crude oils

Relationships in component-fractional and chemical composition of crude oils

Relationships in component-fractional and chemical composition of crude oils

Relationships in component-fractional and chemical composition of crude oils

Relationship in component-fractional and chemical composition of crude oils

Relationship in component-fractional and chemical composition of crude oils

Relationship in component-fractional and chemical composition of crude oil

Relationship in component-fractional and chemical composition of crude oil

Relationships in component-fractional and chemical composition of crude oils

Relationships in component-fractional and chemical composition of crude oils