A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT, ALBERTA PART 1: WHOLE OIL SAMPLES.

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. Relative to a core sample, the fireflood-produced oils exhibited a significant reduction in density and viscosity which began early in the production cycle. This behaviour was correlated with a marked increase in material boiling in the naphtha and middle distillate ranges and a concomitant decrease in the residue cut. The sulfur and nitrogen contents in the produced oils decreased relative to the core sample. A reduction in the acid number of the produced oil samples was coupled with an increase in the oxygen content as the firefiood proceeded. The relationship between these changes and the dynamics of the in situ combustion process are discussed.     

A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT,ALBERTA PART 2: DISTILLATION CUTS AND CHROMATOGRAPHIC FRACTIONS

ABSTRACT

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. The analytical data for the distillation cuts and chromatographic fractions from a core sample and a number of produced oil samples revealed significant changes as a result of the recovery process, particularly for the naphtha and middle distillate cuts. The residue cut did not exhibit any increase in heteroatom or asphaltene content. None of the changes to the produced oil samples would be expected to negatively impact on the subsequent upgrading process. The relationship between the observed changes to the fractionated oil samples and the dynamics of the in situ combustion process are discussed.     

A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT, ALBERTA PART 2: DISTILLATION CUTS AND CHROMATOGRAPHIC FRACTIONS

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. The analytical data for the distillation cuts and chromatographic fractions from a core sample and a number of produced oil samples revealed significant changes as a result of the recovery process, particularly for the naphtha and middle distillate cuts. The residue cut did not exhibit any increase in heteroatom or asphaltene content. None of the changes to the produced oil samples would be expected to negatively impact on the subsequent upgrading process. The relationship between the observed changes to the fractionated oil samples and the dynamics of the in situ combustion process are discussed.     

CHANGE OF PHYSICAL AND THERMAL DECOMPOSITION PROPERTIES OF IN SITU HEAVY OIL WITH STEAM TEMPERATURE

ABSTRACT

Ikiztepe crude oil was subjected to four different steam temperatures during steam injection which was applied as an enhanced oil recovery process on a linear limestone model saturated with oil. Produced oils were characterized using density, viscosity measurements, pyrolysis experiments utilizing TGA and elemental analysis runs. Results showed that produced crude oils change in measured characteristics as compared to the original oil. These changes include an increase in H/C, and cracking activation energy, decrease in density, viscosity and amount of residue remaining after cracking (coke). Also, decrease in asphaltene amount, changes in the elemental composition of asphaltenes and increase in the cracking activation energies were observed at 225 °C run. These measurements show that the produced oils get lighter and differ compositionally from the original oil as steam temperature increases. Decrease in elemental sulphur amount is one of the major changes when environmental considerations are concerned. Residual oil left in the limestone pack on the other hand shows an increase in the low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO) activation energies as determined from TGA combustion experiments on the samples taken from the pack after steam injection experiments.     

APPLICATION OF PETROLEUM DEMULSIFICATION TECHNOLOGY TO SHALE OIL EMULSIONS

ABSTRACT

Demulsification, the process of emulsion separation, of water-in-oil shale oil emulsions produced by several methods was accomplished using commercial chemical demulsifiers which are used typically for petroleum demulsification. The shale oil emulsions were produced from Green River shale by one in situ and three different above-ground retorts, an in situ high pressure/ high temperature steam process, and by washing both re tort-produced and hydrotreated shale oils.     

EVALUATION OF OIL YIELD LOSSES DURING THE RETORTING OF OIL SHALE AT LOW VOID FRACTIONS. PART 1. THE EFFECTS OF PARTICLE SIZE AND RESOURCE GRADE

ABSTRACT

The economics of vertical modified in situ (VMIS) retorting of oil shale can be improved by decreasing the quantity of oil shale which is mined and transported to the surface. However, decreasing the quantity of oil shale removed from the retort also decreases the void fraction in the shale bed and this can affect the retorting process. The Western Research Institute has completed a series of experiments designed to investigate the effects of different experimental parameters on retorting oil shale at low void fractions. The effects of changes in the experimental parameters, oil shale particle size and resource grade, on oil yield losses have been evaluated using previously described oil yield loss diagnostic methods. These methods show that cracking–plus–combustion losses are the major and more variable source of chemically related oil yield losses. In experiments investigating changes in oil shale particle size, these losses correlate with the temperature differential between thermocouples in the rubble and in the interior of the oil shale particles. The data from the experiments investigating the effects of changes in resource grade on oil yield losses do not follow this correlation because of additional combustion of the produced oil during the lean resource grade experiment. Coking losses from experiments investigating both parameters were found to decrease with increased heating rate of the oil shale when significant differences in the heating rate were observed.     

CHANGE OF PHYSICAL AND THERMAL DECOMPOSITION PROPERTIES OF IN SITU HEAVY OIL WITH STEAM TEMPERATURE

Ikiztepe crude oil was subjected to four different steam temperatures during steam injection which was applied as an enhanced oil recovery process on a linear limestone model saturated with oil. Produced oils were characterized using density, viscosity measurements, pyrolysis experiments utilizing TGA and elemental analysis runs. Results showed that produced crude oils change in measured characteristics as compared to the original oil. These changes include an increase in H/C, and cracking activation energy, decrease in density, viscosity and amount of residue remaining after cracking (coke). Also, decrease in asphaltene amount, changes in the elemental composition of asphaltenes and increase in the cracking activation energies were observed at 225 °C run. These measurements show that the produced oils get lighter and differ compositionally from the original oil as steam temperature increases. Decrease in elemental sulphur amount is one of the major changes when environmental considerations are concerned. Residual oil left in the limestone pack on the other hand shows an increase in the low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO) activation energies as determined from TGA combustion experiments on the samples taken from the pack after steam injection experiments.     

UPGRADING OF SUGAR CANE BAGASSE BY THERMAL PROCESSES. 6. SIMULATED DISTILLATION OF OILS OBTAINED FROM COAL CO-PROCESSING WITH SUGAR CANE BAGASSE OIL

Abstract

In this paper simulated distillation employing HRGC (high resolution gas chromatography) was used to evaluate the quality of the oils obtained from coal co-processing using sugar cane bagasse oil as the process solvent. Four coal samples were used, two of them corresponding to Brazilian coals, one to an American coal and one to a Polish coal. The results shows that the oil produced through co-processing with sugarcane bagasse oil presents characteristics of lighter oils than those obtained by direct liquefaction of coal with monoethanolamine as solvent.     

EMPIRICAL APPROACH FOR THE DIAGNOSTIC ANALYSIS OF CHEMICALLY RELATED OIL YIELD LOSSES DURING THE RETORTING OF OIL SHALE

ABSTRACT

The analysis of chemically related oil yield losses during the retorting of oil shale is important for understanding the chemistry of a process, supplying data for modeling efforts and process control of a production facility. Previously developed gas chromatographic correlations for evaluating oil yield losses were duplicated using combined gas chromatograph/mass spectrometric data. Evaluation of these results through calculation of local oil yields indicated that they were higher than expected when compared to material balance oil yields.

A new correlation was developed to estimate the fraction of oil lost by cracking plus combustion. The approach to the new correlation was based on selection of steranes and pentacyclic triterpanes as the species in shale oil which would undergo cracking and combustion to yield selected aromatic compounds. Evaluation of the results from this correlation for determination of local oil yields was found to produce acceptable results.

The two approaches for estimating the fraction of oil lost by cracking plus combustion are compared. The differences appear to be that the earlier approach is dependent upon severe cracking and combustion conditions. The new approach for determining the fraction of oil lost by cracking plus combustion appears to be applicable to a wider range of process conditions and therefore is more useful in research.     

An Experimental Study of Secondary WAG Injection in a Low-Temperature Carbonate Reservoir in Different Miscibility Conditions

Abstract

This experimental study is aimed at evaluation of the performance of secondary WAG injection in carbonate cores at different pressures. To do so, a comprehensive series of high-pressure high-temperature (HPHT) core flooding tests are conducted. The fluid system includes reservoir dead and live crude oil, CO₂, and synthetic brine while the chosen porous media consists of a number of fractured carbonate core samples. Parameters such as oil recovery factor, water and oil production rates, and pressure drop along the core are recorded for both dead and live oil. According to results, at first increasing pressure improves the oil recovery, but this improvement after MMP is not as significant as it is before MMP. Also recoveries of dead and live oils at same pressure show different values due to differences in miscibility condition of injected gas. Then as the graphs demonstrate, relative permeability reduction due to hysteresis effect has dominant effect on pressure drop curves. Finally, as the production rate curves show, nearly all of the remained oil after breakthrough is produced as the gas is being produced and almost no oil can be recovered during water production portions.     

Desulfurization of Simulated Oils by Microwave Chemical Methods

Abstract

Microwave technology was introduced for the desulfurization of sulfurous crude oil and the influence of microwave processes on removing benzothiophene sulfur and bi-benzothiophene sulfur in simulated oils was studied in this article. The results manifested that the desulfurization efficiencies of BBPV, formylhydroperoxide and peroxyacetic acid for an oil sample (simulated oil 2) containing bi-benzothiophene were better than for the oil sample (simulated oil 1) containing benzothiophene. When dosages of BBPV increased from 0.5% to 4%, the desulfurizing efficiencies of simulated oil 1 and 2 were raised from 19.8% to 53.7%, and 48.0% to 64.2%, respectively. With the increase of temperature, the reaction order desulfurization of the simulated oils by microwave increased, and the rate of the microwave reaction increased. The desulfurizing efficiency increases along with the temperature in the same time.     

RELATIONSHIP BETWEEN PETROLEUM COMPOSITION AND DEPOSITIONAL ENVIRONMENT OF PETROLEUM SOURCE ROCKS FROM THE GULF OF SUEZ AND THE WESTERN DESERT OF EGYPT

ABSTRACT

Crude oils from the Gulf of Suez and the North Western Desert of Egypt have been analyzed for geochemical biomarkers using GC and GC-MS techniques. The biomarker compositions of the crude oils have been used to differentiate crude oils of non-marine, normal marine and marine carbonate sources. The geochemical features of Zaafarana crude oil from the Gulf of Suez Basin indicate a marine carbonate depositional setting. One crude oil from Budran however, possesses geochemical characteristics consistent with an origin from source rock deposited in normal marine conditions. Bahar and Morgan show normal marine source rock deposition environment with terrigenous organic matter input. On the other hand, the crude oils from the North Western Desert have bulk and biomarker characteristics cosistent with non-marine depositional setting, with the exception of one oil sample which appears to have a mixed marine/terrestrial sources. The presence of oleanane in some of these oils suggests source rocks deposited in deltaic or near shore environment in Post Cretaceous Basin.     

The formation of the composition of unrecovered oils in producing oil fields of Tatarstan

Analysis of the composition of unrecovered and produced oils of Tatarstan shows that the adsorption-chromatographic process upon oil motion in the reservoir during recovery is manifested in an increase in the density and viscosity of unrecovered oils. They do not contain light hydrocarbons of the IBP ?200°C fraction and have dramatically smaller concentrations of both the least polar lube oil hydrocarbons and alcohol-benzene-extractable resins exhibiting the highest polarity. According to GLC data, unrecovered and produced oils are classified with different subtypes of chemical type A1 of nonbiodegraded oils: produced oils are grouped with subtype 1 and unrecovered oils are attributed to subtype 2. The dynamics of the development of areas of produced oils with the use of a technique based on the activation of reservoir microflora showed that the process of the microbiological oxidation manifests itself in the preferential ability of reservoir microflora to digest C₁₂-C₃₄ n-alkane hydrocarbons as compared to cyclic hydrocarbons. Normal C₁₂-C₂₀ alkanes are consumed by bacteria before hydrocarbons with a greater number of carbon atoms C₂₀-C₃₄ of this series. An analysis of extracts from aqueous infusions of oils showed that the dissolution process leads to the transfer of 0.04–0.07 wt % hydrocarbons and heteroatomic components from oil to water.     

CHEMICAL COMPOSITION OF OIL SHALE II. DEPENDENCE ON THE EXTRACTION PROCESS

ABSTRACT

Eastern and Western U.S. and Australian oil shales were retorted in a fixed-bed, bench-scale retorter, using nitrogen and carbon dioxide as sweep gases. The resulting shale oils were chemically characterized by GC/MS techniques. Shale oils extracted by nitrogen and carbon dioxide retorting processes were found to have different chemical compositions, even when applied to the same oil shale samples. The extraction process dependent nature of shale oils is fully assessed in this paper and the information may be used for comparison among various extraction processes as well as for choosing appropriate upgrading processes for the crude shale oils.     

DETERMINATION OF THE CONTINUITY IN OIL RESERVOIRS USING PRINCIPAL COMPONENT ANALYSIS OF BIOMARKERS DATA

ABSTRACT

In order to develop an optimum production scheme in an oil reservoir it is very important to determine accurately the internal geometry (continuity and compartmentalisation). Usually geophysical logging methods are used for this purpose, which are expensive and time consuming. Additional information can be derived on the basis of differences in physical properties and/or in chemical composition within oil samples produced from separate compartments in a reservoir. The major problem is that oil samples coming from the same formation exhibit minor physico-chemical differences. Hence, it is difficult to develop a reliable discriminating algorithm. This paper presents a novel analytical approach, which enables accurate discrimination between the oil samples coming from different wells in a layered reservoir, which exhibit minute differences in physical and in chemical properties. The method uses the biomarkers data obtained from the GC–MS m/z 191 fragmentogram of the saturated fraction of the oils. Principal Component Analysis (PCA) method was applied to discriminate oils into groups. The classification scheme obtained using the proposed analytical method was found to be in agreement with the available geological and geophysical data, which describes the internal geometry of the reservoir under study.     

Regeneration of Used Lubricating Oils by Supercritical Fluid Extraction

Abstract

Regeneration of used lubricating oils by supercritical fluid extraction were investigated. The broken-down additives and impurities were removed by the high selectivity of supercritical fluid, and high-quality lube oil was obtained. Corrosion and waste-disposal problems produced by older acid-clay process have been lessened.     

DIRECT LIQUEFACTION OF WOOD BY CATALYST AND WATER

ABSTRACT

Wood powder suspended in water was directly liquefied in the presence of nickel carbonate or potassium carbonate without a reducing agent like hydrogen and/or carbon monoxide. Heavy oils with carbon and hydrogen contents of about 80% were produced and their heats of combustion ranged from 29.3 to 33.4 MJ/kg. Total carbon recovery in the form of heavy oils was about 24%.     

异构脱蜡润滑油基础油组成对其性质的影响

以加氢裂化尾油和加氢处理重质减压馏分油为原料,采用异构脱蜡工艺制备润滑油基础油。分析基础油的性质,并采用质谱和¹³C核磁共振分析异构脱蜡基础油的烃组成和烃结构,考察异构脱蜡润滑油基础油的烃组成和烃结构对其性质的影响。结果表明,对于异构脱蜡润滑油基础油,在多环环烷烃质量分数、链烷碳质量分数和平均碳数相近的条件下,黏度指数随着异构烷碳与正构烷碳质量分数之比的增大而减小,倾点随着异构烷碳与正构烷碳质量分数之比的增大而降低;在多环环烷烃质量分数、异构烷碳与正构烷碳质量分数之比相近的条件下,黏度指数和倾点随着分子的平均碳数减少而降低。     

The Effect of Fractures' Geometrical Properties on the Recovery Mechanism of the Top-down In Situ Combustion Process

Abstract

The top-down in situ combustion (ISC) involves the stable propagation of the combustion front from the top vertical injector to the bottom horizontal producer. Apart from laboratory studies in conventional sandstones, no application of the process in fractured carbonates has been addressed yet. The authors modified a successful combustion tube history matched model of an Iranian low-permeable heavy oil reservoir called Kuh-E-Mond to investigate the feasibility of ISC in fractured carbonate reservoirs mimicking block-scale combustion cells. Effects of fractured geometrical properties such as orientation, location, extension, density, spacing, and dispersion were considered. Results confirmed a higher outcome in the case of optimum vertical or horizontal fracture density and spacing. Vertical fractures located at the lateral sides of the cell enhanced the process in terms of ultimate oil recovery and oxygen sweep efficiency. The longer vertical fractures and higher dispersion through the reservoir improved the recoveries compared with the lower efficiency in the case of extended horizontal fractures and raised their dispersion through the reservoir. Simulation analysis confirmed that top-down ISC has higher feasibility in the case of highly networked fractures through reservoirs such as those in the Persian Gulf coast.     

Vapex—Gravity-assisted Film Drainage for Heavy Oil Recovery

Abstract

Reservoir heavy oils of viscosity higher than 20 cp are difficult to recover efficiently. A new vapor extraction process called Vapex which uses horizontal wells and volatile solvents is being developed, primarily in Canada. This process lowers the viscosity of the oil by dilution and the oil is produced by gravity drainage (vertical movement of fluids) to horizontal wells placed low in the reservoir. More oil should be produced at lower production and energy costs. The Vapex process is outlined in this article and followed by some experimental work demonstrating gravity drainage flow in films at the macro- and micro-scale.