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Advanced Technologies for Enhanced Oil Recovery (EOR) and Improved Oil Recovery (IOR)

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "H1: Petroleum Engineering".

Deadline for manuscript submissions: closed (31 January 2023) | Viewed by 24382

Special Issue Editors

National University of Oil and Gas «Gubkin University», Leninski Prospect 65, Moscow, Russia
Interests: field chemistry; reagents and technologies for oil production intensification; enhanced oil recovery; oil treatment; development and implementation of reagents for technologies to improve oil recovery and increase well productivity
Department of Petroleum Engineering, Enhanced Oil Recovery Laboratory, Kazan Federal University, Kazan, Kremlevskaya str. 18, 420008 Kazan, Russia
Interests: crude oil; enhanced oil recovery; in-situ combustion; gas injection; surfactant flooding; polymer flooding; foaming agents; catalytic oil upgrading; gas hydrates; thermodynamics; thermal analysis and calorimetry; phase behavior
Special Issues, Collections and Topics in MDPI journals
Department of Physical Chemistry, Kazan Federal University, Kremlevskaya Str. 18, 420008 Kazan, Russia
Interests: efficient hydrocarbon recovery including: steam injection; in-situ combustion (ISC); new technologies for in-situ heavy oil upgrading; catalytic in-situ oil upgrading; catalytic oxidation of crude oil; chemical flooding especially for interfacial phenomena (wettability of solids, interfacial tension, foams and emulsions) and profile control and water shutoff technologies
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, China
Interests: enhanced oil recovery (EOR); profile control and water shutoff technologies; foam injection; surfactant flooding; gas injection; emulsification and polymer gel

Special Issue Information

Dear Colleagues,

We would like to invite you to submit manuscripts to a Special Issue of the journal Energies on the topic of “Advanced technologies for enhanced oil recovery (EOR) and improved oil recovery (IOR)”.

With the long-time development of oil fields, a lot of reservoirs have been coming into their mature stage. How to reverse the decline of mature fields and increase the overall oil recovery is a challenging issue facing the oil field operators all over the world. Simultaneously, a lot of new reserves are found in hard-to-recover reservoirs, such as heavy and extra-heavy oil, shale oil, oil shale, tight oil reservoir. The development of these hard-to-recover reserves requires more efficient EOR/IOR methods.

In this special issue, we are going to publish a special edition devoted to related topics in EOR/IOR area, in particular, development of chemical agents as well as their roles and efficiency in EOR/IOR process; interaction between different phases in water/chemical solution/oil/rock systemand multiphase flow in porous media evaluated by filtration experiments as well as modeling and simulation; mechanism of EOR/IOR; injection-water chemistry; oilfield chemistry; and new technologies and research advancement for intensifying oil and gas production. We welcome original research articles (both empirical and theoretical) and review articles.

Dr. Lyubov A. Magadova
Dr. Mikhail A. Varfolomeev
Dr. Chengdong Yuan
Dr. Fayang Jin
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • enhanced oil recovery (EOR)
  • improved oil recovery (IOR)
  • oilfield chemistry
  • injection water chemistry
  • multiphase flow in porous media
  • interaction in water/chemical solution/oil/rock system
  • filtration experiments
  • numerical simulation
  • chemical flooding (surfactant, polymer, ion-modified water, etc.)
  • foam
  • acid treatment
  • hydraulic fracturing

Published Papers (13 papers)

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Research

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16 pages, 2901 KiB  
Article
Understanding & Screening of DCW through Application of Data Analysis of Experiments and ML/AI
by Tony Thomas, Pushpa Sharma and Dharmendra Kumar Gupta
Energies 2023, 16(8), 3376; https://0-doi-org.brum.beds.ac.uk/10.3390/en16083376 - 12 Apr 2023
Cited by 1 | Viewed by 1234
Abstract
An oil recovery technique, different composition waterflooding (DCW), dependent on the varying injected water composition has been the subject of various research work in the past decades. Research work has been carried out at the lab, well and field scale whereby the introduction [...] Read more.
An oil recovery technique, different composition waterflooding (DCW), dependent on the varying injected water composition has been the subject of various research work in the past decades. Research work has been carried out at the lab, well and field scale whereby the introduction of different injection water composition vis-a-vis the connate water is seen to bring about improvements in the oil recovery (improvements in both macroscopic and microscopic recoveries) based on the chemical reactions, while being sustainable from ease of implementation and reduced carbon footprint points of view. Although extensive research has been conducted, the main chemical mechanisms behind the oil recovery are not yet concluded upon. This research work performs a data analysis of the various experiments, identifies gaps in existing experimentation and proposes a comprehensive experimentation measurement reporting at the system, rock, brine and oil levels that leads to enhanced understanding of the underlying recovery mechanisms and their associated parameters. Secondly, a sustainable approach of implementing Machine Learning (ML) and Artificial Intelligence Tools (AIT) is proposed and implemented which aids in improving the screening of the value added from this DCW recovery. Two primary interaction mechanisms are identified as part of this research, gaps in current experimentation are identified with recommendations on what other parameters need to be measured and finally the accuracy of application of ML/AI tools is demonstrated. This work also provides for efficient and fast screening before application of more resource and cost intensive modeling of the subsurface earth system. Improved understanding, knowledge and screening enables making better decisions in implementation of DCW, which is a sustainable recovery option given the current state of affairs with zero carbon and net zero initiatives being on the rise. Full article
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12 pages, 2475 KiB  
Article
Examination of the Structure and Definition of the Mechanism of Formation of Products by Pyrolysis of Tarim Crude Oil
by Yue Ma, Fan Shao, Jing Wang, Han Yang and Changtao Yue
Energies 2023, 16(4), 2073; https://0-doi-org.brum.beds.ac.uk/10.3390/en16042073 - 20 Feb 2023
Viewed by 1208
Abstract
Pyrolysis of crude oil is an important way to generate natural gas. However, the current analysis of pyrolysis gas carbon isotopes and the study of gas generation dynamics are not unified, and the genesis and accumulation of gas reservoirs are needed to conduct [...] Read more.
Pyrolysis of crude oil is an important way to generate natural gas. However, the current analysis of pyrolysis gas carbon isotopes and the study of gas generation dynamics are not unified, and the genesis and accumulation of gas reservoirs are needed to conduct in-depth discussions. Therefore, Tarim crude oil samples in China were selected to perform thermal simulation experiments using an autoclave. The pyrolysis hydrocarbon production yield, carbon isotope characteristics and gas-generation process of crude oil samples in Tarim Basin were studied by GC-MS, FT-IR and carbon isotope analysis, respectively. The compositions of the Tarim Oilfield were determined, including the 83.69% content of hydrocarbons, the 14.08% content of aromatic compounds, and lower than 3% content of heteroatom compounds. The non-monotonic linear relationship of C2-5 isotopes may be due to the complexity of crude oil, and the formation of gaseous hydrocarbons can be divided into three stages. The results showed that the δ13C distribution range of C2-5 hydrocarbons was −40.5% to −10.5%, and the δ13C distribution of methane was −53.3% to −27.4%. The lowest δ13C value for methane occurs at 350 °C, and the corresponding carbon isotope value is −53.3%. When the pyrolysis temperature range is 250–300 °C, crude oil undergoes volatilization and preliminary pyrolysis, and the C4-5 output exceeds 95%. When the temperature rises to 300–500 °C, the aliphatic hydrocarbon chain in crude oil begins to crack, the side and branch chains of aromatic and heteroatomic compounds are broken, and C4-5 begins to crack to form C1-3. Finally, the temperature rises to 500–600 °C, and C3-5 begins to deeply crack into C1-2, and eventually all is converted to methane. Full article
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27 pages, 14791 KiB  
Article
Laboratory Study of the Influence of Fluid Rheology on the Characteristics of Created Hydraulic Fracture
by Anna Shevtsova, Sergey Stanchits, Maria Bobrova, Egor Filev, Sergey Borodin, Vladimir Stukachev and Lyubov Magadova
Energies 2022, 15(11), 3858; https://0-doi-org.brum.beds.ac.uk/10.3390/en15113858 - 24 May 2022
Cited by 2 | Viewed by 1447
Abstract
In the last decade, the negative impact of hydraulic fracturing fluids on the reservoir properties has been noted, which has led to the new trend of improving characteristics and developing new hydraulic fracturing fluids. As an alternative option to the traditionally used cross-linked [...] Read more.
In the last decade, the negative impact of hydraulic fracturing fluids on the reservoir properties has been noted, which has led to the new trend of improving characteristics and developing new hydraulic fracturing fluids. As an alternative option to the traditionally used cross-linked fluids based on guar solution, in our laboratory we have tested fluids having a branched spatial structure, which allowed them to hold and transport proppants, despite the low viscosity of this kind of fluids (100–200 mPa·s measured at 100 s−1). Existing theoretical models of hydraulic fracture (HF) propagation have some limitations in predicting the influence of fracturing fluids on reservoir properties. Unfortunately, in situ experiments in the target reservoir are difficult and expensive. Thus, laboratory experiments can be considered as a reasonable alternative for testing new fluids, since they can provide comprehensive information about the properties of the created HF before the application of a new hydraulic fracturing technique in the field conditions. This paper presents the results of an experimental study of hydraulic fracturing of granite samples in laboratory conditions. The injection of water- and oil-based unconventional fracturing fluids was performed to study the influence of fluid rheology on the dynamics of the hydraulic fracture propagation process and parameters of the created HF. We have found that the fracturing fluid viscosity affects the parameters of the created HF, such as aperture, propagation velocity, breakdown pressure, and HF surface tortuosity. The obtained relationships can be taken into account for Hydraulic Fracture modelling, which may increase the efficiency of the hydraulic fracturing in the field conditions. Full article
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21 pages, 4004 KiB  
Article
Effective Inhibition of Carbon Steel Corrosion by Waterborne Polyurethane Based on N-tert-Butyl Diethanolamine in 2M HCl: Experimental and Computational Findings
by Yulia F. Zaripova, Sherzod Razhabov, Roman S. Pavelyev, Svetlana S. Vinogradova, Renat R. Nazmutdinov, Iskander R. Vakhitov and Mikhail A. Varfolomeev
Energies 2022, 15(5), 1939; https://0-doi-org.brum.beds.ac.uk/10.3390/en15051939 - 07 Mar 2022
Cited by 1 | Viewed by 2012
Abstract
The efficiency of corrosion inhibition for waterborne polyurethane based on N-tert-butyl diethanolamine (tB-WPU) is investigated using different techniques. Corrosion weight loss, open circuit potential experiments, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements show that both a commercial reagent and [...] Read more.
The efficiency of corrosion inhibition for waterborne polyurethane based on N-tert-butyl diethanolamine (tB-WPU) is investigated using different techniques. Corrosion weight loss, open circuit potential experiments, electrochemical impedance spectroscopy, and potentiodynamic polarization measurements show that both a commercial reagent and a polyurethane-based inhibitor prevent corrosion at increasing temperature to 50 °C. At 75 °C, the activity of both reagents is reduced. In stirring conditions, the effectiveness of acid corrosion inhibition (25 °C, 500 ppm) drops abruptly from 89.5% to 60.7%, which is related presumably to the complexity of binding the polymer molecules to the metal surface. As follows from thermodynamic calculations, the adsorption of tB-WPU on the metal surface in 2M HCl can be treated as a physisorption. Model quantum–chemical calculations support the experimental studies and elucidate the nature of steel surface–inhibitor molecule chemical bond, which is realized mainly by carboxyl and amino groups. It is concluded that WPUs can be considered as a perspective alternative to commercial oilfield reagents due to their versatility. Full article
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14 pages, 2658 KiB  
Article
Novel Nonylphenol Polyethoxylated Based Surfactants for Enhanced Oil Recovery for High-Mineralization Carbonate Reservoir
by Emil R. Saifullin, Polina O. Putintseva, Rustam N. Sagirov, Mikhail A. Varfolomeev, Chengdong Yuan, Roman S. Pavelyev, Sergey A. Nazarychev, Aleksei O. Malahov, Lucia Akimushkina, Dmitrii A. Zharkov, Alexey O. Bykov and Ulukbek Mirzakimov
Energies 2022, 15(3), 961; https://0-doi-org.brum.beds.ac.uk/10.3390/en15030961 - 28 Jan 2022
Cited by 3 | Viewed by 1608
Abstract
Surfactant flooding can mobilize trapped oil and change the wettability of the rock to be more hydrophilic, which increases the oil recovery factor. However, the selection of surfactants is difficult in the case of high salinity conditions. In this work, we synthesized three [...] Read more.
Surfactant flooding can mobilize trapped oil and change the wettability of the rock to be more hydrophilic, which increases the oil recovery factor. However, the selection of surfactants is difficult in the case of high salinity conditions. In this work, we synthesized three novel anionic-nonionic surfactants based on widely used nonionic surfactant nonylphenol polyethoxylated (NPEO) and evaluated their efficiencies for enhanced oil recovery (EOR) in high salinity water (20% NaCl). The modified surfactants showed a decrease in interfacial tension (IFT) up to 10 times compared with the nonionic precursor. All surfactants had changed the wettability of rock to be more hydrophilic according to contact angle measurements. The effectiveness of surfactants was proved by spontaneous imbibition experiments, in which the synthesized surfactants showed a better displacement efficiency and increased oil production by 1.5–2 times. Filtration experiments showed an increase in oil recovery factor by 2–2.5 times in comparison with the nonionic NPEO. These promising results prove that the synthesis of new surfactants by modifying NPEO is successful and indicate that these novel surfactants have a great potential for EOR in high salinity reservoirs. Full article
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15 pages, 4161 KiB  
Article
Screening of Surfactants for Flooding at High-Mineralization Conditions: Two Production Zones of Carbonate Reservoir
by Aleksei O. Malahov, Emil R. Saifullin, Mikhail A. Varfolomeev, Sergey A. Nazarychev, Aidar Z. Mustafin, Chengdong Yuan, Igor P. Novikov, Dmitrii A. Zharkov, Rustam N. Sagirov and Rail I. Kadyrov
Energies 2022, 15(2), 411; https://0-doi-org.brum.beds.ac.uk/10.3390/en15020411 - 06 Jan 2022
Cited by 3 | Viewed by 1242
Abstract
The selection of effective surfactants potentially can mobilize oil up to 50% of residuals in mature carbonate oilfields. Surfactants’ screening for such oilfields usually is complicated by the high salinity of water, high lipophilicity of the rock surface, and the heterogeneous structure. A [...] Read more.
The selection of effective surfactants potentially can mobilize oil up to 50% of residuals in mature carbonate oilfields. Surfactants’ screening for such oilfields usually is complicated by the high salinity of water, high lipophilicity of the rock surface, and the heterogeneous structure. A consideration of features of the oilfield properties, as well as separate production zones, can increase the deep insight of surfactants’ influence and increase the effectiveness of surfactant flooding. This article is devoted to the screening of surfactants for two production zones (Bashkirian and Vereian) of the Ivinskoe carbonate oilfield with high water salinity and heterogeneity. The standard core study of both production zones revealed no significant differences in permeability and porosity. On the other hand, an X-ray study of core samples showed differences in their structure and the presence of microporosity in the Bashkirian stage. The effectiveness of four different types of surfactants and surfactant blends were evaluated for both production zones by two different oil displacement mechanisms: spontaneous imbibition and filtration experiments. Results showed the higher effect of surfactants on wettability alteration and imbibition mechanisms for the Bashkirian cores with microporosity and a higher oil displacement factor in the flooding experiments for the Vereian homogeneous cores with lower oil viscosity. Full article
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18 pages, 3971 KiB  
Article
Comprehensive Study of the Action of Corrosion Inhibitors Based on Quaternary Ammonium Compounds in Solutions of Hydrochloric and Sulfamic Acids
by Silin Mikhail, Magadova Lyubov, Davletshina Lucia, Poteshkina Kira, Kotekhova Viktoriia and Galkina Alexandra
Energies 2022, 15(1), 24; https://0-doi-org.brum.beds.ac.uk/10.3390/en15010024 - 21 Dec 2021
Cited by 3 | Viewed by 2469
Abstract
Acid treatments are one of the methods for intensifying oil and gas production. Corrosion is a significant factor affecting the performance of oilfield equipment. There are many different methods of preventing corrosion, but corrosion inhibitors are most commonly used in industry. The protective [...] Read more.
Acid treatments are one of the methods for intensifying oil and gas production. Corrosion is a significant factor affecting the performance of oilfield equipment. There are many different methods of preventing corrosion, but corrosion inhibitors are most commonly used in industry. The protective effect of the inhibitor is directly determined by the effective adsorption of surfactants on the metal surface. For an indirect assessment of the adsorption of the inhibitor, a comprehensive research method is proposed based on the determination of the interfacial tension of acid compositions and steel plates’ contact angle of wetting after corrosion tests. It was found that in hydrochloric acid the adsorption of the inhibitor IC-1 reaches a maximum after 6 h, an increase in the acid concentration in the range of 5–15% wt. has a negative effect on the activity of the inhibitor. For sulfamic acid, the maximum adsorption of the IC-2 inhibitor is observed after 24 h, an increase in acid concentration has a positive effect on surfactants. Full article
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13 pages, 3123 KiB  
Article
Characteristics of Viscoelastic-Surfactant-Induced Wettability Alteration in Porous Media
by Kexing Li, Bowen Chen, Wanfen Pu, Xueqi Jing, Chengdong Yuan and Mikhail Varfolomeev
Energies 2021, 14(24), 8454; https://0-doi-org.brum.beds.ac.uk/10.3390/en14248454 - 14 Dec 2021
Cited by 3 | Viewed by 1587
Abstract
Wettability alteration is one of the most important mechanisms of surfactant flooding. In this work, the combined Amott/USBM (United States Bureau of Mines) method was applied to study the average wettability alteration of initially neutral cores after viscoelastic-surfactant (VES) filtration. The effects of [...] Read more.
Wettability alteration is one of the most important mechanisms of surfactant flooding. In this work, the combined Amott/USBM (United States Bureau of Mines) method was applied to study the average wettability alteration of initially neutral cores after viscoelastic-surfactant (VES) filtration. The effects of static aging, dynamic aging, VES concentration, filtration flow rate, and pore radius on the alteration of a core’s average wettability were studied. The wettability-alteration trends measured by Amott and USBM were consistent, demonstrating that the overall hydrophilicity of the core was enhanced after VES filtration. The wettability alterations of the core brought about by dynamic aging were more significant than by static aging. The viscoelastic properties of the VES played an important role in altering the wettability. In addition, the ability of the VES to affect the core’s wettability was significantly enhanced when the VES concentration was increased, which was beneficial in increasing VES adsorption on the pore-wall surface, thus altering the overall wettability of the core. Increasing filtration flow rates can destroy those high-viscosity VES aggregates via the higher shear rate. A higher retention of VES makes the core more hydrophilic. The difference in the wettability of cores with different pore radius after VES filtration was not significant. The alteration of average wettability caused by VES in porous media provides a new vision for studying the EOR mechanism of VES. Full article
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14 pages, 2944 KiB  
Article
Nonylphenol Ethoxylate Surfactants Modified by Carboxyl Groups for Foam EOR at High-Salinity Conditions
by Emil R. Saifullin, Shinar Zhanbossynova, Dmitrii A. Zharkov, Roman S. Pavelyev, Chengdong Yuan, Mikhail A. Varfolomeev, Ulukbek Zh. Mirzakimov, Sergey Yu. Ivanov and Sergey A. Sitnov
Energies 2021, 14(24), 8205; https://0-doi-org.brum.beds.ac.uk/10.3390/en14248205 - 07 Dec 2021
Cited by 2 | Viewed by 2836
Abstract
High mineralization of water complicates the use of foam in reservoir conditions. Anionic–nonionic surfactants are one of the best candidates for these conditions since they have both high surface activity and salt tolerance. One of the ways to obtain anionic–nonionic surfactants is to [...] Read more.
High mineralization of water complicates the use of foam in reservoir conditions. Anionic–nonionic surfactants are one of the best candidates for these conditions since they have both high surface activity and salt tolerance. One of the ways to obtain anionic–nonionic surfactants is to modify nonionic surfactants by an anionic group. The type of the group and its chemical structure can strongly affect the properties of the surfactant. In this work, widely-produced nonionic surfactant nonylphenol (12) ethoxylate (NP12EO) was modified by new types of carboxylic groups through the implementation of maleic (NP12EO-MA) and succinic (NP12EO-SA) anhydrides with different saturation levels. The main objectives of this work were to compare synthesized surfactants with nonionic precursor and to reveal the influence of unsaturated bonds in the carboxyl group on the properties of the foam. NaCl concentration up to 20 wt% was used to simulate high mineralization conditions, as well as to assess the effect of unsaturated bonds on foam properties. Synthesized anionic–nonionic surfactants retained surfactant solubility and long-term stability in high-salinity water, but have better foaming ability, as well as higher apparent viscosity, in porous media. The presence of an unsaturated bond in NP12EO-MA surfactant lowers foaming ability at high mineralization. Full article
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13 pages, 2051 KiB  
Article
Influence of Carbonate Minerals on Heavy Oil Oxidation Behavior and Kinetics by TG-FTIR
by Kristina A. Ariskina, Zhenfeng Ding, Mustafa Abaas, Chengdong Yuan, Dmitrii A. Emelianov, Qing Chen and Mikhail A. Varfolomeev
Energies 2021, 14(23), 8136; https://0-doi-org.brum.beds.ac.uk/10.3390/en14238136 - 04 Dec 2021
Cited by 3 | Viewed by 1392
Abstract
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) [...] Read more.
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. Full article
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18 pages, 5893 KiB  
Article
Numerical Simulation via CFD Methods of Nitrogen Flooding in Carbonate Fractured-Vuggy Reservoirs
by Kexing Li, Bowen Chen, Wanfen Pu, Jianhai Wang, Yongliang Liu, Mikhail Varfolomeev and Chengdong Yuan
Energies 2021, 14(22), 7554; https://0-doi-org.brum.beds.ac.uk/10.3390/en14227554 - 12 Nov 2021
Cited by 2 | Viewed by 1557
Abstract
A reservoir-scale numerical conceptual model was established according to the actual geological characteristics of a carbonate fractured-vuggy reservoir. Considering the difference in density and viscosity of fluids under reservoir conditions, CFD (computational fluid dynamic) porous medium model was applied to simulate the process [...] Read more.
A reservoir-scale numerical conceptual model was established according to the actual geological characteristics of a carbonate fractured-vuggy reservoir. Considering the difference in density and viscosity of fluids under reservoir conditions, CFD (computational fluid dynamic) porous medium model was applied to simulate the process of nitrogen displacement in a fractured-vuggy reservoir after water flooding. The effects of gas injection rate, injection mode, and injector–producer location relation were studied. The results show that nitrogen flooding can yield additional oil recovery of 7–15% after water flooding. Low-speed nitrogen injection is beneficial in obtaining higher oil recovery. High speed injection can expand the sweep area, but gas channeling occurs more easily. In gas–water mixed injection mode, there is fluid disturbance in the reservoir. The gas channeling is faster in low injector–high producer mode, while the high injector–low producer mode is beneficial for increasing the gas sweep range. Nevertheless, the increment of recovery is closely related to well pattern. After nitrogen flooding, there are still a lot of remaining oil distributed in the trap area of gas cap and bottom water in the reservoir that water and gas injection can’t sweep. The establishment of the numerical conceptual model compensates for the deficiency of physical simulation research, stating that only limited parameters can be simulated during experiments, and provides theoretical bases for nitrogen flooding in fractured-vuggy reservoir. Full article
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17 pages, 2970 KiB  
Article
Combustion Behavior and Kinetics Analysis of Isothermal Oxidized Oils from Fengcheng Extra-Heavy Oil
by Liangliang Wang, Jiexiang Wang, Wanfen Pu and Tengfei Wang
Energies 2021, 14(19), 6294; https://0-doi-org.brum.beds.ac.uk/10.3390/en14196294 - 02 Oct 2021
Cited by 8 | Viewed by 1742
Abstract
The low-temperature oxidation (LTO) of heavy oil is of great significance for the combustion front stability, which directly influences the efficiency and safety of in-situ combustion (ISC). To provide feasible heating by artificial ignition before the implementation of ISC in the Xinjiang Fengcheng [...] Read more.
The low-temperature oxidation (LTO) of heavy oil is of great significance for the combustion front stability, which directly influences the efficiency and safety of in-situ combustion (ISC). To provide feasible heating by artificial ignition before the implementation of ISC in the Xinjiang Fengcheng (FC) oilfields, this paper investigates the oxidation behavior of FC extra-heavy oil and its isothermal oxidized oils. Firstly, FC extra-heavy oil was subjected to isothermal oxidation experiments conducted utilizing an oxidation reactor, and the physical properties of the gaseous products and oxidized oils were analyzed. The combustion behavior of the FC extra-heavy oil and oxidized oils was then studied by non-isothermal thermogravimetry and differential scanning calorimetry. Subsequently, the Friedman and Ozawa–Flynn–Wall methods were adopted to perform kinetic analysis. Oxygen consumption was always greater than the production of CO and CO2, so oxygen addition reactions were the main pathway in heavy oil LTO. H/C decreased to 8.31% from 20.94% when the oxidation temperature rose from 50 °C to 150 °C, which deepened the oxidation degree. The density and viscosity of 200 °C to 350 °C oxidized oils increased at a slower rate, which may be related to the LTO heat effect. The change law of temperature interval, peak temperature, and mass loss of the oxidized oils had a good correlation with the static oxidation temperature. Compared with other oxidized oils, the peak heat flow and enthalpy of 350 °C oxidized oil increased significantly with high-temperature combustion, and were 42.4 mW/mg and 17.77 kJ/mol, respectively. The activation energy of 350 °C oxidized oil began to decrease obviously around a conversion rate of 0.4, which indicates that it was beneficial to coke deposition with stronger activity. Finally, we came up with LTO reaction mechanisms and put forward a reasonable preheating temperature for the application of ISC in FC oilfields. Full article
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19 pages, 6488 KiB  
Technical Note
Applicability Assessment of Viscoelastic Surfactants and Synthetic Polymers as a Base of Hydraulic Fracturing Fluids
by Silin Mihail, Magadova Lyubov, Malkin Denis, Krisanova Polina, Borodin Sergei and Filatov Andrey
Energies 2022, 15(8), 2827; https://0-doi-org.brum.beds.ac.uk/10.3390/en15082827 - 13 Apr 2022
Cited by 7 | Viewed by 1566
Abstract
Hydraulic fracturing (HF) is currently the most widespread and effective method of oil production stimulation. The most commonly used fracturing fluid is crosslinked guar gels. However, when using these systems, problems such as clogging of the pore space, cracking, and proppant packing with [...] Read more.
Hydraulic fracturing (HF) is currently the most widespread and effective method of oil production stimulation. The most commonly used fracturing fluid is crosslinked guar gels. However, when using these systems, problems such as clogging of the pore space, cracking, and proppant packing with the remains of the undestroyed polymer arise. Therefore, the efficiency of the hydraulic fracturing process decreases. In this work, compositions based on viscoelastic surfactants (VES) and synthetic polymers (SP) were considered as alternatives capable of minimizing these disadvantages. Most often, the possibility of using a composition as a fracturing fluid is evaluated using rotational viscometry. However, rotational viscometry is not capable of fully assessing the structural and mechanical properties of fracturing fluid. This leads to a reduced spread of systems based on VES and SP. This paper proposes an integrated approach to assessing the effectiveness of a water-based fracturing fluid. The proposed comprehensive approach includes an assessment of the main characteristics of water-based fracturing fluids, including an analysis of their structural and mechanical properties, which is based on a combination of rotational and oscillatory rheology and a comparative analysis of methods for studying the influence of fluids on the reservoir rock. The use of the developed approach to assess the technological properties of fracturing fluids makes it possible to demonstrate the potential applicability of new, unconventional fracturing fluids such as systems based on VES and SP. Full article
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