Classification Of Crude Oils Research Articles

Reservoir geochemistry of the Tazhong oilfield in the Tarim Basin, China, Part I. Geochemical characteristics and genetic classification of crude oils

According to the assemblage characteristics of saturated hydrocarbon biomarkers in crude oils and their geochemical implications, this study has proposed, for the first time, the criteria for the genetic classification of crude oils in the Tazhong area of the Tarim Basin, China. Crude oils from the area studied are classified as three genetic types: Type-I is characterized by the low contents of C29 norhopane, extremely abundant contents of gammacerane, low contents of rearranged sterane and relatively high contents of regular C28 sterane; the geochemical properties of type-II crude oils are opposite to those of type-I crude oils; the parameters for type-III crude oils are intermediate between type-I and type-II. Results of oil correlation indicated that type-I crude oils were derived from Cambrian-Lower Ordovician hydrocarbon source rocks, type-II curde oils originated from Middle-Upper Ordovician hydrocarbon source rocks and type-III crude oils are of mixed origin.

Geographical classification of crude oils by Kohonen self-organizing maps

In the analysis of an environmental disaster caused by spillage of crude oil, limitation of the possible sources to a few geographical origins can help in the identification of the polluting vessel from a group of potential candidates. In this paper we show that Kohonen self-organizing maps (or Kohonen neural networks) can classify samples of crude oils on the basis of gas chromatography–mass spectrometry (GC–MS) descriptors, in terms of geographical origin, with a high degree of accuracy. Two data sets were investigated – one from Instituto Hidrográfico (Lisbon, Portugal) with 188 samples from 20 geographical origins, and another from EUROCRUDE ® with 374 samples. After training the Kohonen self-organizing maps with a training set, predictions were obtained for an independent test set. Correct predictions were obtained for 70% and 60% of the test sets for the two studies, respectively. Ensembles of networks were highly interesting for the calculation of a prediction score, which can be used as a measure of the reliability of the prediction. For the samples with high prediction scores, the percentage of correct predictions jumped to 94–96%. The ability of the maps to identify a given origin is very much dependent on the availability of samples from that class in the training set. Equally good predictions were obtained for a small test set of weathered samples. This investigation adds value to the GC–MS descriptors already in use for practical analytical work, suggesting new ways to ferret out useful knowledge from them.

Asphalt production technology. From engineering art to science

In the last third of the last century, important progress was made in developing the scientific basis for oxidized asphalt production technology. The classification of crude oils and mathematical model developed allow quantitatively predicting the basic parameters of asphalt production based on vacuum distillation and oxidation process using the reference properties of the crude oil.

Application of geochemical parameters for classification of crude oils from Egypt into source-related types

Seven crude oils representing the different petroleum-bearing basins in the Western Desert were characterized by a variety of biomarker and nonbiomarker parameters. For comparison, one crude oil from the Gulf of Suez region has also been studied. The oils have been analyzed for geochemical biomarkers using GC and GC-MS techniques. The results reveal significant differences within the oils that suggest five oil types. Type 1 oils from the Gulf of Suez show C 29/C 30 17α(H) hopane ratio >1, high C 35 homohopane index, and the presence of considerable amounts of gammacerane indicating a marine saline carbonate or evaporite source rock and highly reducing (low Eh) conditions. Type 2 oils from Matruh basin and type 3 oils from Shushan basin are very similar and show relatively high Pr/Ph ratios, low sulfur and metal contents, paucity of C 30 steranes and the presence of high relative abundance of 17α(H) diahopane (C 30*) suggesting that they probably originated from source rocks containing a significant proportion of higher plant material. Another related feature of these oils is the absence of 18α(H)-oleanane which suggests a source age older than Cretaceous. Type 4 oils from Abu-Elgharadig basin show terpane distribution dominated by C 24 tricyclic, absence of C 30*-diahopane and medium diasterane/sterane ratios which reflect generation from marine siliciclastic source rocks. Type 5 oils from Alamein basin possess source biomarkers indicating a mixed contribution of terrestrial and marine sources. The presence of measurable amounts of oleanane in this type of oils suggests source rocks deposited in deltaic or near shore environment in Post-Cretaceous basin.

97/03636 Rheological properties and settling behavior influences in CWS pipeline flow

A new classification of crude oils was developed using gas chromatography. With the LSER equation of Abraham et al., five parameters (intermolecular interaction terms) were obtained characterizing physicochemically 47 crude oils. This classification is in good agreement with the crude oil chemical composition and constitutes a first step in the explanation of their behaviour in the production steps.

97/03631 Plastics recycling coupled with enhanced oil recovery. A critical survey of the concept

A new classification of crude oils was developed using gas chromatography. With the LSER equation of Abraham et al., five parameters (intermolecular interaction terms) were obtained characterizing physicochemically 47 crude oils. This classification is in good agreement with the crude oil chemical composition and constitutes a first step in the explanation of their behaviour in the production steps.

Crude oils: modelling from chromatographic data—a new tool for classification

A new classification of crude oils was developed using gas chromatography. With the LSER equation of Abraham et al., five parameters (intermolecular interaction terms) were obtained characterizing physicochemically 47 crude oils. This classification is in good agreement with the crude oil chemical composition and constitutes a first step in the explanation of their behaviour in the production steps.

Integrated Geochemical Workstation on the PC: Data Base, GIS Mapping, and Multivariate Statistical Predictions: ABSTRACT

With the advent of more powerful personal computers and corresponding graphical software, it is possible to integrate large geochemical crude oil data bases with geographical information system software. In addition, classification of crude oils based on genetic origin using multivariate modeling techniques can be accomplished on the same platform. This allows for the effortless mapping of geochemical parameters ranging from bulk characteristics such as percent sulfur to specific biomarker ratios like the gammacerane index. Oil families determined from principal component and cluster analyses can be mapped. Biomarker mass chromatograms, stored as pictures in the data base, can also be accessed from a map view. Microsoft's[reg sign] Access data base software, Esri's ArcView[reg sign] GIS mapping software, and InfoMatrix's Pirouette[reg sign] statistical modeling programs, along with Adobe's Acrobat[reg sign] electronic publishing software can all be tied together using a Pentium[reg sign] class personal computer under Microsoft's Windows operating system. An example of a geochemical study of almost 200 oils from Venezuela will be illustrated.

Characterization of Heavy Oils. 2. Definition of a Significant Characterizing Parameter To Ensure the Reliability of Predictive Methods for PVT Calculations

A new and significant characterizing parameter (q{sub 30}) which is easy to calculate is defined. This parameter can indicate in advance whether the PVT (pressure-volume-temperature) calculations performed on a crude oil using a predictive method will be in good agreement with experimental data. This parameter leads to a new classification of crude oils. When q{sub 30} is small, the crude oil is considered as classical and all of its PVT properties can be accurately predicted. When q{sub 30} is large, the crude oil is classified as critical-like; i.e., the prediction of some PVT properties may lead to significant deviations when compared to experimental values. In the latter case, a tuning process is proposed which in all cases improves the agreement between experimental and calculated data. Moreover, variance analysis theory is applied to estimate the experimental errors during a differential vaporization.

Classification of crude oils produced byin situ combustion

Classification of crude oils produced byin situ combustion

Determination of concentration of metalloporphyrins in native hydrocarbon raw materials

The assessment and classification of crude oils from new areas, studies of geochemical relationships in the occurrence of metalloporphyrins in the sedimentary cover, and the calculation of reserves of metalloporphyrins in crude oils from various fields are all based on measurements of the concentrations of vanadyl and nickel porphyrins (VP and NP) by electronic spectroscopy. For a number of reasons, this method will give only relative concentrations. In order to evaluate the prospects for using hydrocarbon raw materials as a source of valuable associated components, reliable and rapid methods of analysis are necessary. The work described in this article was aimed at improving the accuracy of measurement of metalloporphyrin complexes in crude oils, asphalts, and bituminous components of disseminated organic matter (DOM) in rocks, through improvement of the existing methods for calculating the concentration of metalloporphyrins and segregating an analytical porphyrin concentrate.

Biomarkers and Geochemical Classification of Oils in Some Basins of the Commonwealth of Independent States

Contemporary geochemical classifications of crude oils are based on the composition and quantitative ratios of individual hydrocarbons, mainly biomarkers. This paper discusses biomarkers whose composition is closely related to crude oil formation factors such as type of original organic matter; degree of catagenesis of organic matter, kerogen, and crudes; degree of biodegradation of the oil; facies conditions of diagenesis; and geological age of the original organic matter. The identification, by mass chromatography, of a large number of biomarkers resulted in classification of crude oils from basins in the Commonwealth of Independent States. Some of the biomarkers thus determined are n-alkanes, isoprenanes, C[sub 21]-C[sub 30] steranes, tricyclic and pentacyclic terpanes, cheilantanes, hopanes, 25, 28, 30- trisnorhopanes, 28, 30- and 25, 30-bisnorthopanes, [gamma] - lupane, [gamma]-cerane, and others. The geochemical conditions for petroleum formation and the geochemical classifications are discussed in light of the following basins and stratigraphical complexes: western Siberia, eastern Siberia, Timano-Pechora and near Caspian. In the four basins, some 200 crudes were studied, in each of which about 20 different correlation ratios of the most important biomarkers were determined. This work has resulted in the elucidation of the effect of the main factors of petroleum formation on the geochemistrymore » and petroleum generation in these basins and stratigraphic complexes. The study of biomarker composition has made possible the determination of the geological and geochemical conditions for petroleum formation, correlation of composition with the geological age, chemical type of the original organic matter, determination of the severity of the oxidizing conditions, the degree of microbiological activity in diagenesis, and provided information on the lithology of source rocks and other geochemical parameters of petroleum formation.« less

Organic geochemistry of Venezuelan extra-heavy crude oils 2. Molecular assessment of biodegradation

The extent of biodegradation of extra-heavy crude oils from the Eastern Venezuelan basin (Orinoco “Tar” Belt) has been assessed using biological marker compounds which include steranes, triterpanes, aromatic steroids and phenanthrenes (analyzed by GC-MS) and petroporphrins (analyzed by HPLC). The analyses indicate that biodegradation takes place in two regions, namely “surface or close to surface” and “subsurface”, with a different pattern of biodegradation taking place at each type of location. Some oils show patterns of biomarkers which may be the combined result of degradation at both main sites of biodegradation. However, two empirical biodegradation parameters are proposed to achieve this classification. The classification of crude oils in terms of degree of biodegradation is further complicated by the identification of “mixed crudes”.

Use of Trace Elements for Classification of Crude Oils into Families--Example from Alberta, Canada

This study shows that a combination of instrumental neutron-activation analysis and stepwise multiple-discriminant function analysis is equally successful and valuable in correctly classifying crude oils which had previously been grouped into families based on organic geochemical analysis. In the present study, 11 trace elements were determined by instrumental neutron-activation analysis in 75 Alberta crude oils from similar lithostratigraphic situations and the samples grouped into the same families, plus an ungrouped data set. Stepwise multiple-discriminant function analysis shows that only S, Co, Se, V, and Br are significant discriminators of the three grouped data sets. Further, the efficacy of the discriminant analysis is confirmed using multiresponse permutation procedures. Among the grouped data, 89.1% of the crude oils were correctly classified on the basis of their trace-element content, 70% of which were at a probability level of more than 90%. For some misclassified samples, information from the statistical analysis together with knowledge of the local lithostratigraphy and hydrodynamics can be used to indicate mixing or migration phenomena. For example, crude oil in the Lower Cretaceous Basal Colorado Sandstone at Cessford appears to be a mixture from sources within the lower Colorado Group and in the underlying Mannville Group; in contrast, the only source of crude oil in the Upper Devonian Winterburn Group at Youngstown appears to be the overlying Lower Cretaceous Mannville Group. Among the ungrouped data, the trace-element classification for four Triassic crude oils suggests a source in the overlying Lower Cretaceous Mannville Group. The results for crude oils from Carboniferous and Upper Devonian Wabamun Group strata, far below the sub-Cretaceous unconformity, suggest further work is required before a specific source can be identified. In the structurally separated Turner Valley field, the crude oil in Lower Cretaceous Blairmore Group strata seems to have originated from the overlying Colorado Group, whereas that from Carboniferous rocks shows mixed characteristics. Crude oil from the Athabasca oil sand deposit exhibits enigmatic features.--Modified journal abstract.

Fingerprinting of Crude Oils for Pollution Control

Abstract Total, demetallated porphyrins from selected “export” and “weathered” crude oils were analyzed by high performance liquid chromatography (HPLC). The aim was to study the effect, if any, of oil weathering processes on the type and distribution of these compounds and hence, assess the applicability of their HPLC fingerprints in the area of pollution control. The results revealed that petroporphyrins are not readily susceptible to natural weathering processes and that their HPLC fingerprints may be applied to crude oil classification and could supplement other techniques of identifying oil pollutants.

Stratigraphic Comparison of Polish Crude Oils

An approximate, comparative classification of crude oils is given by stratigraphic horizons and depths of occurrences in the Polish fields. Differentiations of crude oils can not be explained unless the heterogeneous character of the primary organic substances is considered.