Oxidation Of Heavy Oil Research Articles

Improving In Situ Combustion for Heavy Oil Recovery: Thermal Behavior and Reaction Kinetics of Mn(acac)3 and Mn-TO Catalysts

In this research work, the catalytic performances of two manganese-based catalysts, manganese (III) acetylacetonate (Mn(acac)3) and manganese tallate (Mn-TO), were studied during the process of Ashalcha heavy oil oxidation under in situ combustion conditions. DSC analysis shows distinct thermal behavior of both ligated catalysts during low- and high-temperature oxidation phases (LTO and HTO); for example, the shifting in peak temperature (Tp) in the HTO at a heating rate of 10 °C/min was reduced by approximately 5.3% for Mn-TO and 2.24% for Mn(acac)3 when compared with uncatalyzed heavy oil. Combined isothermal kinetic analyses using the Friedman and Kissinger–Akahira–Sunose analytic methods have provided insights about activation energies and frequency factors over the whole conversion range, where the catalytic performance of Mn-TO showed low activation energies in both LTO and HTO (Eα of Mn-TO was approximately 13.33% (LTO) and 7.68% (HTO) less than with the heavy oil alone). In addition, calculations of the effective rate constant confirmed the increased oxidation rate trend of both catalysts, with Mn-TO exhibiting the highest values. The findings highlight the potential of these manganese-based catalysts, the Mn-TO catalyst in particular, in optimizing heavy oil oxidation processes. The overall results further contribute to developing more efficient ligand catalyst complexes for sustainable heavy oil recovery while continuously improving their efficient application during in situ combustion in the petroleum industry.

Kinetic investigation of aschalcha heavy oil oxidation in the presence of cobalt biocatalysts during in-situ combustion

The catalytic effect of cobalt tall oil and cobalt sunflower oil catalysts on the oxidation kinetics of heavy crude oil was investigated in this study. Comprehensive kinetic analyses, employing differential scanning calorimetry, thermogravimetric analysis, and kinetic modeling techniques, revealed that the presence of these catalysts significantly influenced the oxidation behavior of heavy oil. The catalysts exhibited pronounced shifts in the DSC and TG curves towards lower temperatures, indicating facilitated initiation of oxidation reactions at lower onset temperatures. Quantitative kinetic parameters, including activation energies and frequency factors, were determined using the Friedman and Kissinger-Akahira-Sunose analyses. The cobalt tall oil catalyst demonstrated superior performance, effectively lowering the activation energy barrier and increasing oxidation rates, particularly at higher conversion degrees. Catalyst characterization techniques, including X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy, revealed the formation of highly crystalline cobalt oxide nanoparticles with optimal dispersion and size distribution, as well as the presence of favorable functional groups for surface interactions. The results elucidated the role of these catalysts in facilitating the oxidation process through the provision of active sites, altered reaction pathways, favorable steric environments, and efficient oxygen activation capabilities. These findings contribute to the development of efficient catalytic systems for heavy oil upgrading processes and offer insights for further optimization of catalyst properties to achieve desired oxidation kinetics behavior.

Improving the in-situ upgrading of extra heavy oil using metal-based oil-soluble catalysts through oxidation process for enhanced oil recovery

The demand for fuel from unconventional sources is increasing all over the world, however, there are still special and strict regulations regarding the methods of enhanced oil recovery as well as the content of the oil produced, including the amount of sulfur. In-situ combustion (ISC) is an attractive thermal method to enhance oil recovery and in-situ upgrading process. In this work, copper (II) oleate and copper (II) stearate were used for the oxidation of extra heavy oil with high sulfur content in the ISC process using a self-designed porous medium thermo-effect cell (PMTEC) and visual combustion tube. Using PMTEC the catalytic performances of the synthesized oil-soluble copper (II) oleate and copper (II) stearate and kinetic parameters such as activation energy using Ozawa-Flynn-Wall method were studied. The X-ray diffraction (XRD) and high-resolution field emission scanning electron microscopy were used to examine the characteristics of in-situ synthesized CuO nanoparticles during oxidation. As shown, the presence of oil-soluble copper (II) stearate and copper (II) oleate reduced oil viscosity from 9964 to 8000 and 6090 mPa˙s, respectively. Following ISC process in porous media in the presence of copper (II) oleate, the high sulfur extra heavy oil upgraded, and its sulfur content decreased from 10.33 to 6.79%. Additionally, SARA analysis revealed that asphaltene and resin content decreased in the presence of oil-soluble catalysts. During the oxidation reaction, homogeneous catalyst decomposed into nanoparticles, and heterogeneous catalyst is distributed uniformly in porous media and played an active role in the catalytic process. It should be noticed that, these kind of oil-soluble catalysts can be novel and highly potential candidates for initiation and oxidation of extra heavy oil in order to decrease the viscosity, enhanced oil recovery and production of the upgraded oil.Graphical abstract

Thermogravimetric Analysis of Heavy Oil Oxidation in the Presence of Nickel Based Catalysts

Thermogravimetric Analysis of Heavy Oil Oxidation in the Presence of Nickel Based Catalysts

Study on the Catalytic Oxidation Modification Effect of Heavy Oil at Low Temperature under the Action of Different Ligand Ferric-Based Systems

This work explores the low-temperature catalytic oxidation of heavy oil (140 °C), resulting in structural changes with reduced heavy components and increased light components. The catalytic oxidation system consists of a catalyst, an oxidant, and a proton donor. Four different complexes of iron-based catalysts were utilized: ferric oleate, iron naphthenate, EDTA–FeNa, and EDDHA–FeNa. Catalytic oxidation processes with these catalysts produced four types of oxygenated oil, which were then analyzed using group composition analysis and a viscosity test. The results show that EDDHA–FeNa is more favorable for the catalytic oxidation of heavy oil in a low-temperature environment, achieving a viscosity reduction rate of 78.57%. Furthermore, the catalytic performance of heavy oil oxidation was investigated using EDDHA–FeNa as catalyst under three conditions: the amount of catalyst, oxidant and reaction temperature. These findings may provide researchers valuable guidance and principles for the investigation and development of advanced catalytic viscosity reduction of heavy oil.

The Impact of the Initiators on Heavy Oil Oxidation in Porous Media during In Situ Combustion for In Situ Upgrading Process

The Impact of the Initiators on Heavy Oil Oxidation in Porous Media during In Situ Combustion for In Situ Upgrading Process

BUTEN-1-in BUTEN-2-yə İZOMERLƏŞMƏSİ REAKSİYASINDA BİNAR KOBALT TƏRKİBLİ KATALİZATORLARIN AKTİVLİYİ

Hydrogen is considered the main source of chemical energy that can be converted directly into electricity and with the help of fuel cells into zero emissions of harmful waste, such as volatile organic compounds, nitrogen oxides and carbon. The production of hydrogen in accordance with the generation of energy using a fuel cell is considered a promising alternative to stationary and portable power generation plants in the future. Various methods are used to produce hydrogen: water electrolysis, gasification, partial oxidation of heavy oil and steam corrugation of organic compounds. Currently, in industry, about 90% of hydrogen is produced by the reaction of high-temperature steam reforming of light fractions of natural gas or oil. An attractive alternative to hydrogen production is the reaction of ethanol steam reforming. The activity of binary iron-cobalt, zinc-cobalt and magnesium-cobalt oxide catalysts in the reaction of isomerization of butene-1 to butenes-2 was studied. Iron-cobalt, zinc-cobalt and magnesium-cobalt oxide catalysts were prepared by co-precipitation from aqueous solutions of iron, zinc, magnesium and cobalt nitrate salts. The resulting mixture was evaporated at 95-100°C, then the resulting precipitate was dried at 100-120°C and then decomposed at 250°C until the nitrogen oxides were completely separated. The resulting solid was calcined at 700°C for 10 hours. Thus, 27 catalysts were prepared satisfying the following conditions: mA/NB, where A is Mo, Ti, Cu; cis, m,n=1-9, m+n=10. The isomerization reaction of butene-1 to butene-2 was carried out at a rate of 1200 h-1 volume of feedstock in the temperature range of 150-400°C. The reactor was filled with 5 mL of 1-2 mm thick catalyst and fed with a reaction mixture consisting of butene-1 and nitrogen. The ratio of butene-1 to nitrogen is 1:9. It is shown that with increasing cobalt content in the Fe-Co-o catalyst composition, its activity in the isomerization reaction reaches a maximum on catalysts with equivalent ratio of initial elements. The ratio of trans- and cis-butenes-2 practically does not change and is equal to 1.2. It is found that both Lewis acid centers and Bransted acid centers are present on the surface of this catalyst in approximately equal amounts. It was found that with increasing zinc content in the catalyst composition, the degree of butene-1 isomerization decreases and the ratio of trans-butene-2 to cis-butene-2 increases from 0 to 2.1, indicating the presence of Lewis and Bronsted acid centers on the surface of Zn-Co-O catalysts. It is found that for the Mg-Co-O catalytic system the ratio of trans and cis butenes-2 yields varies in the range 0.8-1.5. It is shown that, in the whole temperature range studied, the atomic ratio of cobalt and magnesium has a strong influence on their activity in the reaction of Butene-1 isomerization into Butene-2. It is found that the number of Lewis and Bronsted acid centers is practically independent of the composition of the Mg-Co-O catalytic system. Based on the study of the reaction of butene-1 to butene-2 isomerization on binary cobalt-containing catalysts, it was found that the samples with equimolar ratios of primary elements in Fe-Co-O catalysts, as well as samples with one of the predominant elements in the catalytic systems Zn-Co-O and Mg-Co-O are active. Keywords: Isomerization, butene-1, butenes-2, binary catalysts Cobalt oxide.

Experimental study on the reliability of thermal analysis techniques in the in-situ combustion of heavy oil

ABSTRACT In situ combustion (ISC) is an effective method to enhance heavy oil (HO) recovery. Thermal analysis (TA) techniques are considered ideal tools for study the HO oxidation. However, the reliability of TA data has been affected by the strong adhesion of high viscosity HO to the substrate and crucible. Consequently, there has been a deviation in the DTA peak temperature for both low and high-temperature oxidation of HO and HO/clay mixtures at 7°C, 19°C, and 8°C, 11°C respectively. Additionally, negative values of reaction activation energy (E α ) were observed, reaching up to −1395.94 ± 836.2 kJ mol−1. This study aimed to identify factors that impact TA data reliability and oxidation kinetics. By implementing solutions such as ultrasonic stirring and needle tip loading, this study was able to improve the accuracy and reproducibility of TA data and E α value. The results of this investigation provide valuable insight for future ISC.

Improving the Performance of Heavy Oil Oxidation Using Oil-Soluble Copper-Based Catalysts in In Situ Combustion for the In Situ Upgrading Process

Improving the Performance of Heavy Oil Oxidation Using Oil-Soluble Copper-Based Catalysts in In Situ Combustion for the In Situ Upgrading Process

Optimizing In Situ Combustion with Manganese (II) Oxide Nanoparticle-Catalyzed Heavy Oil Oxidation

The combustion front is a crucial parameter in determining the efficiency of in situ combustion techniques during enhanced oil recovery. Nowadays, catalytic systems are widely believed to be an efficient tool to stabilize the combustion front. This study aimed to investigate the synthesis and catalytic activity of manganese (II) oxide nanoparticles in the high-temperature oxidation of heavy oils. The synthesis and catalytic activity of manganese (II) oxide nanoparticles in the high and low-temperature oxidation regions of heavy oil were investigated in this study. The obtained nanoparticles were characterized and studied by using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TG), nitrogen adsorption and desorption measurements, and differential scanning calorimetry (DSC) thermal analysis combined with the Kissinger isoconversional method. The obtained results showed that the synthesized nanoparticles had an average size of 17 ± 4 nm and a specific surface area of 38.2 ± 0.1 m2 g−1, with a pore size distribution of ~8 nm. The low and high-temperature oxidation processes’ activation energies were found to be 98.9 ± 0.7 kJ/mol and 151.9 ± 0.6 kJ/mol, respectively, in the presence of nanoparticles. However, these parameters were found to be equal to 110.1 ± 1.8 kJ/mol and 142.8 ± 8.3 kJ/mol, respectively, in the absence of nanoparticles. These data were processed further by calculating the corresponding reaction rates. The obtained results indicated that the rate of heavy oil oxidation was higher in the presence of the synthesized nanoparticles, which could play a critical role in stabilizing the combustion front in the in situ combustion process.

Catalytic capacity evolution of montmorillonite in in-situ combustion of heavy oil

Clay minerals such as montmorillonite are significant in petroleum storage and recovery. Montmorillonite (Mt) is a natural solid acid catalyst containing Brønsted and Lewis acid sites and can catalyze heavy oil oxidation (HOO) during in-situ combustion (ISC). However, its catalytic activity largely depends on the heating process of heavy oil. In the study, the catalytic capacity evolution of Mt in ISC of heavy oil was explored with the isoconversional method and thermal analysis. In low-temperature oxidation (LTO) and high-temperature oxidation (HTO) stages, the addition of Mt largely reduced the peak temperatures (Tpeak) of DTA and DTG and the Tpeak of H2O (LTO and HTO stages) and CO2 (HTO stage) in HOO. Notably, Mt did not always show the positive catalytic effect. In LTO stage, the thermal transformation process had a small effect on DTA Tpeak, Tpeak of H2O and CO2, and the reaction activation energy (Eα) of HOO. In HTO stage, the catalytic effect of Mt on HOO was related to its thermal transformation process, especially interlayer water (IW) dehydration and dehydroxylation. In HTO stage, the IW dehydration process of Mt showed the strongest catalytic effect on HOO, significantly reduced DTA Tpeak and Eα, and resulted in the lowest Tpeak of H2O and CO2. The dehydroxylation process of Mt also showed a certain effect, whereas the overlapping process between the dehydration (IW) reaction and partial dehydroxylation reaction of Mt had no positive catalytic effect on HOO. DTA, TG-FTIR, and non-isothermal kinetic analysis further confirmed that the catalytic capacity of Mt in HTO stage was improved by IW dehydration process of Mt and weakened by the dehydroxylation process of Mt.

Sunflower oil as renewable biomass source to develop highly effective oil-soluble catalysts for in-situ combustion of heavy oil

In-situ combustion has received much attention in the last few decades for enhanced heavy oil recovery processes. Although a wide part of research efforts has only focused on the application of different oil soluble catalysts to improve the combustion flame stabilization, the effect of ligand structure and metal–ligand interactions on the performance of heavy oil oxidation in presence of oil soluble catalysts is poorly understood. In this study, sunflower oil as an eco-friendly and cheap source was used to synthesize a new ligand for the preparation of Fe, Ni, Co and Cu-based oil soluble catalysts. The interaction of metals with the ligand was investigated by computational study and the results revealed that Cu-based catalyst was the most effective catalytic system for enhancing heavy oil oxidation process because it possessed the strongest bond energy with the ligand at different temperatures. Subsequently, the impact of oil soluble catalysts on the oxidation of heavy oil was investigated via non-isothermal kinetics and thermodynamic studies using thermogravimetric (TG/DTG) and differential scanning calorimetric analyses (DSC) combined with the isoconversional (Friedman and Kissinger-Akahira-Sunose), and model-based approaches. As anticipated, the kinetic and thermodynamic data demonstrated the efficiency of the used catalysts on the process of heavy oil oxidation process and proved a maximum temperature shift of ∼ 120 °C in high-temperature oxidation zone. To the best of our knowledge, this is the first superior catalyst among investigated oil-soluble catalysts for heavy oil oxidation. The evidence from the obtained results points toward the idea that the choice of the ligand and the associated metal is crucial to achieve the highly active and smart catalytic system for enhanced oil recovery methods.

Effect of Different Water Content and Catalyst on the Performance of Heavy Oil Oxidation in Porous Media for In Situ Upgrading

Effect of Different Water Content and Catalyst on the Performance of Heavy Oil Oxidation in Porous Media for In Situ Upgrading

Oxidation of heavy crude oils under reservoir conditions: Influence of catalysts and the gas phase

In this work the influence of catalysts on in situ combustion process of heavy crude oil has been studied. The heavy crude oil from Russia (Ashal'cha field) oil field was used. The research on oxidation was performed using accelerating rate calorimetry (ARC). The effect of type of metal oxide (NiO, Co3O4, Fe3O4) on catalytic oxidation process of crude oil at conditions close to reservoir's pressure and temperature was investigated. The impact of catalyst particle size on oxidation process of crude oil has been revealed. The composition of gas mixture has been shown to alter the activity of the catalyst in oxidation process. The correlation between type of catalyst as well as the composition of gas phase and kinetic parameters of reaction was found. Arrhenius kinetic parameters were derived from experimental data of crude oil oxidation.

Effects of kaolinite and its thermal transformation on oxidation of heavy oil

Kaolinite is a common 1:1 layered clay mineral in oil reservoirs and also a natural solid acid catalyst. Some studies have shown that kaolinite has a catalytic effect on the oxidation of heavy oil. Its catalytic effect depends on the type and amount of acid sites and is closely related to its thermal transformation, particularly the dehydroxylation process. The effects of kaolinite and its thermal transformation on the oxidation of heavy oil were investigated with thermal analysis and the Ozawa-Flynn-Wall isoconversional method. The results revealed that kaolinite had significant effects on the High-temperature oxidation (HTO) and Fuel deposition (FD) stages of heavy oil oxidation, but its effect on the Low-temperature oxidation (LTO) stage was small. In the HTO stage, the temperature at which the CO2 release rate peaked decreased dramatically, whereas the temperature at which the H2O release rate peaked increased remarkably. With the increase in the content of added kaolinite, the maximum activation energy in the FD stage of the oxidation reaction of heavy oil and the average activation energy in the HTO stage gradually decreased. It was noteworthy that the transformation of kaolinite upon thermal treatment, especially the dehydroxylation process above 400 °C, resulted in a progressive decline in the peak temperature in the HTO stage of heavy oil, but had little influence on that in the LTO stage of heavy oil oxidation.

Cyclic In-Situ Combustion Process for Improved Heavy Oil Recovery after Cyclic Steam Stimulation

Summary Cyclic in-situ combustion (ISC) is a novel process with great potential for thermal enhanced oil recovery (EOR). In this study, a 3D physical simulation experiment of cyclic ISC after cyclic steam stimulation (CSS) was carried out for the first time. The mass loss during heavy oil oxidation was studied by thermogravimetry (TG) and the preheating temperature of sandpack was determined by differential scanning calorimeter (DSC). The oxidation process of heavy oil in a porous medium was investigated by a heavy oil static oxidation experiment. The development characteristics and EOR mechanism of cyclic ISC after CSS were studied through 3D physical simulation experiments and the characteristics of the coking zone was studied by scanning electron microscope (SEM) and computed tomography (CT). The results of the thermal analysis indicate that three different regions were observed with increasing temperature: low-temperature oxidation zone (LTO), fuel deposition zone (FD), and high-temperature oxidation zone (HTO). When the temperature reaches 480°C, the mixed oil sand has the most exothermic effect and the high-temperature oxidation reaction is the most vigorous. The results of the 3D physical simulation show that steam channeling and steam overlay in CSS reduced the swept volume of steam and heat usage rate. During the cyclic ISC, the oil bank can overcome the heterogeneity of the oil reservoir caused by steam channeling and steam overlay, which makes the combustion front move forward smoothly. Cyclic ISC can greatly increase the temperature of the zone near the well, and upgrade the crude oil through cracking to reduce the viscosity of heavy oil. The foaming oil formed by the dissolution of flue gas improves the fluidity of the crude oil. The oil recovery of CSS is 19.3%, and the oil recovery of cyclic ISC increased by 13.2%. SEM and CT show that flake black solid coke was attached to the surface of the sand at the coking zone. The coking zone is a porous medium structure with a porosity of 35.14%, which has little effect on the oil recovery in the process of cyclic ISC.

СКРИНИНГ УГЛЕВОДОРОДОКИСЛЯЮЩИХ МИКРООРГАНИЗМОВ ДЛЯ БИОРЕМЕДИАЦИИ ПОЧВ, ЗАГРЯЗНЕННЫХ НЕФТЬЮ И НЕФТЕПРОДУКТАМИ

Accidents with oil and petroleum product spills pose a serious threat to environmental safety and human health. To date, measures to eliminate the effects of pollution have mainly been reduced to the use of physical and chemical methods, which are characterized by high cost and many restrictive factors. Microbiological reclamation is a promising approach to solving the problem of cleaning environmental objects from oil pollution. The purpose of this work was to isolate native microflora from the deposits of viscous and ultra-viscous oil to form an association that contributes to the degradation of heavy oil. As a result of screening of hydrocarbon-oxidizing microorganisms, 6 highly active isolates were selected from the bottomhole zones of oil wells of the Bashkir tier of deposits of the Republic of Tatarstan. It has been established that they take part in the oxidation and biological degradation of heavy oil with a specific density of 0.89-0.91 g/cm3. In the experiment with monocultures, the transformation of oil did not exceed 34%, but under the influence of the association, the value of the indicator reached 52%. Under the influence of the association of microorganisms, a significant decrease in the viscosity of oil was noted. The data obtained indicate the prospects for further study of the hydrocarbon-oxidizing ability of the selected microorganisms and the use of this association as the basis of biological products for the elimination of oil and petroleum product spills, rehabilitation of the environment.

Thermo-oxidative characteristics and kinetics of light, heavy, and extra-heavy crude oils using accelerating rate calorimetry

The thermo-oxidative characteristics and kinetics of crude oil directly affected the combustion performance and oil upgrading. This paper brought an in-depth analysis regarding quasi-adiabatic oxidation of crude oil that was still less well-understood. Firstly, the thermo-oxidative characteristics of light, heavy, and extra-heavy oils were studied using accelerating rate calorimetry (ARC). The thermo-oxidative kinetic analysis was then conducted. Particular emphasis was put on the differences into the auto-ignition temperature, exothermic extension of reactions, and kinetic parameters of heavy and extra-heavy oils, with the intent of achieving stable combustion and heavy oil upgrading. The results showed that the light oil encountered heat release triggered by low-temperature oxidation at the reservoir pressure and temperature (7.8 MPa and 95 °C), and its self-ignition temperature was determined to be 100 °C. A continuous heat release was observed in the entire oxidation process, suggesting the air injection might be appropriate for the light oil reservoir. There was no self-exothermic signal at the reservoir pressure and temperature (6.3 MPa and 35 °C) during heavy oil oxidation, and the onset self-exothermic oxidation temperature was found to be 50 °C. Compared with heavy oil, the extra-heavy oil had the obviously higher onset self-exothermic temperature and auto-ignition temperature. This meant that higher ignition temperatures and more lasting ignition time were required when considering in-situ combustion (ISC) of extra-heavy oil. According to the ARC results obtained, we suggested that the near-wellbore areas of the heavy and extra-heavy oil reservoirs were heated up to 120 and 180 °C, respectively. In this scenario, a large amount of heat could be released due to oil oxidation, thereby causing highly efficient upgrading of heavy oil. Additionally, the values of activation energy further confirmed that the heavy oil could be oxidized more easily compared to the extra-heavy oil. The oxidation reactions of heavy oil were less concentration-dependent in comparison with light and extra-heavy oils, indicated by the reaction order. Some new insights derived from this study facilitated achieving rapid and stable combustion, resulting in crude oil upgrading.

Influence of Carbonate Minerals on Heavy Oil Oxidation Behavior and Kinetics by TG-FTIR

The impact of rock minerals on the performance of in situ combustion (ISC) techniques for enhanced oil recovery (EOR) is very important. This work is aimed at investigating the influence of carbonate rocks (dolomite and calcite) on heavy oil oxidation by Thermogravimetry–Fourier-Transform-Infrared (TG-FT-IR) coupled analysis. Two heavy oils with 19.70° and 14.10° API were investigated. Kinetic analysis was performed using TG data by differential and integral isoconversional methods. From TG-DTG curves, three reaction stages, i.e., low-temperature oxidation (LTO), fuel deposition (FD), and high-temperature oxidation (HTO), were defined for both two heavy oil samples, and their reaction mechanism was explained combining the FT-IR data. After the addition of calcite or dolomite, three reaction stages became two with the disappearance of FD, and a significant shift of reaction stages into lower temperatures was also observed. These significant changes in oxidation behavior are because calcite and dolomite promoted the coke formation and combustion by reducing the activation energy barrier and changing reaction pathways, which results in a smooth transition from LTO to HTO. Dolomite exhibited a slightly better promotion effect on LTO-FD than calcite, while calcite exhibited a better acceleration effect on FD-HTO than dolomite in terms of shifting reaction stages. Generally, calcite exhibited a better catalytic effect than dolomite. In spite of the different catalytic performance of calcite and dolomite, they do both show positive effects on combustion process regardless of the difference in the properties and composition of heavy oils. The findings in this work indicate that calcite and dolomite rocks are favorable for the ISC process, and when it comes to the ISC kinetics, the interaction between crude oil and rock must be considered.

Isothermal oxidation behavior of heavy crude oil and its low-temperature oxidized oils: Implications for in-situ upgrading of heavy oil

Oxidation of heavy oil is essential for the success of in-situ combustion (ISC) projects. However, the isothermal oxidation behavior of heavy oil has not been well understood. In this work, the static oxidation experiments at temperatures of 80, 120, 160, and 200 °C were conducted to obtain the low-temperature oxidized oils (LTOO). Subsequently, the heat release caused by oxidation reactions of heavy crude oil and its LTOO at temperatures of 100, 200, 300, 400, and 500 °C was thoroughly examined. The results indicated that heavy crude oil was subjected to heat release yielded by low-temperature oxidation (LTO) at 100 °C. At the initial oxidation stage, the peak heat flow at 400 °C for heavy crude oil was obviously greater than that at 500 °C, different from the cases of the other four oxidized oils. For all the heavy oils used, the combustion at 400 °C produced a more lasting thermal effect than that at 500 °C. All the heavy oils used showed similar exothermic behavior at 100 and 200 °C. But at 300 °C, the LTO of the oil oxidized at 160 °C released more heat in comparison with that of the oil oxidized at 200 °C, which was thought to be caused by the saturate and aromatic components present in these two oxidized oils. Compared to the other four heavy oils, the combustion at 400 °C for the oil oxidized at 200 °C released fairly higher heat. However, there were minor differences in the isothermal DSC curves at 500 °C for all the heavy oils, indicating that LTO reactions at temperatures no greater than 200 °C produced negligible influence on heavy oil combustion at 500 °C. For this reason, a reasonable increase in the ignition temperature was recommendable when achieving ISC of heavy oils with deep LTO degrees and ultra-heavy oils.