Article
Engineering, Geological
Hai Qu, Chengying Li, Chengwei Qi, Xiangjun Chen, Yang Xu, Hong Jun, Xiaoguang Wu
Summary: This study systematically investigates the effects of LN2 freezing on deep shale gas reservoirs. LN2 freezing effectively increases pore volume and induces the formation of fractures in deep shale. Complex fracture networks are generated at micro and macro levels. Shales with fewer clay minerals are ideal targets for LN2 fracturing. Regression models were developed to predict the mechanical strengths of deep shale after LN2 freezing. These findings provide fundamental guidance for the development of deep shale resources in a feasible and environmentally acceptable approach.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Geological
Hai Qu, Zhelun Li, Chengying Li, Xu Liu, Zhijun Zeng, Yang Xu, Ying Liu
Summary: This study investigates the fracturing performances of liquid nitrogen (LN) in low-brittle shales with bedding planes. It was found that LN fracturing can lower fracture initiation pressure and promote fracture propagation compared to hydraulic fracturing. Moreover, LN can thermally induce fractures and deteriorate shale structure.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Energy & Fuels
J. Alexandra Hakala, Amelia N. Paukert Vankeuren, Peter P. Scheuermann, Christina Lopano, George D. Guthrie
Summary: This study used laboratory experiments and reaction path modeling to identify mineral precipitation reactions in hydraulically fractured shale, demonstrating their potential impact on reservoir performance. The agreement between geochemical models and experimental results suggests that numerical models can effectively screen potential fluid-mineral reactions in unconventional reservoirs.
Article
Thermodynamics
Sihai Li, Shicheng Zhang, Huilin Xing, Yushi Zou
Summary: The introduction of CO2 in deep formations has complex effects on geochemical/geophysical processes, CO2 geological storage, and oil/gas recovery. Previous studies have focused on long-term geochemical reactions in low carbonate content reservoirs, neglecting the short-term CO2-brine-rock interaction in carbonate-rich formations. This study quantifies the properties of carbonate-rich shale reservoirs after CO2 fracturing and reveals the alteration mechanisms through soaking experiments and multi-scale tests.
Article
Chemistry, Multidisciplinary
Chunyan Bao, Meng Zhou, Yuexiang Cai
Summary: This study investigates the effect of low-temperature fracturing with liquid nitrogen on shale crack propagation through experiments and simulations. It is found that different crack development modes occur depending on the degree of homogeneity. The study also analyzes the influence of parameters such as heat transfer coefficient and in situ stress on shale temperature, stress distribution, and crack propagation.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Geological
Hai Qu, Shimao Tang, Ying Liu, Pengpeng Huang, Xiaoguang Wu, Zhonghua Liu, Chengying Li
Summary: The study shows that using liquid nitrogen (LN2) for shale fracturing can decrease the breakdown pressure, activate pre-existing fractures and bedding planes, and enhance formation permeability. Lower stress anisotropy, higher pumping rate, and lower bedding plane angle result in more complex fractures.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Polymer Science
Mingwei Wang, Wen Wu, Shuyang Chen, Song Li, Tao Li, Gensheng Ni, Yu Fu, Wen Zhou
Summary: This paper obtained the formula of CO2 foam gel fracturing fluid through experimental optimization and studied its rheological properties under different temperatures and pressures. The results showed that foam quality and temperature are the main influencing factors, which are of great significance for understanding and evaluating the flow characteristics of CO2 foam gel fracturing fluid and the design of shale gas reservoir fracturing operations.
Article
Chemistry, Physical
Hai Qu, Yushuang Hu, Ruichang Guo, Congcong Lin, Jianian Xu, Hong Jun, Xiangjun Chen
Summary: Freezing by liquid nitrogen (LN2) can effectively alter the rock structure of deep shales and increase their permeability. This study investigated the pore structure alteration of deep shales treated by LN2 freezing and developed a model to predict the increased porosity. The results showed that LN2 induces bedding planes and longitudinal fractures, creating high-conductivity fracture networks in shale.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Engineering, Environmental
Wenrui Shi, Ling Zhu, Meiyu Guo, Zisang Huang, Ganlu Wang, Lijie Lin, Li He, Yong Liao, Haoran He, Junshi Gong
Summary: Shale oil resources in China are abundant, but the traditional hydraulic fracturing technique consumes a large amount of water and causes environmental pollution. This study finds that CO2 fracturing technology can effectively reduce water consumption and store CO2, with CO2 methanol-based fracturing being the most effective.
RESOURCES CONSERVATION AND RECYCLING
(2023)
Article
Mechanics
Songcai Han, Qi Gao, Junchao Yang, Lei Wang, Yuanfang Cheng, Chuanliang Yan, Xian Shi
Summary: A fully coupled thermo-hydro-mechanical (T-H-M) model combined with the statistical meso-damage theory is proposed to investigate the trans-scale progressive cracking process of shale gas reservoirs stimulated by liquid nitrogen (LN2). Numerical results demonstrate that fracturing using LN2 can generate fractures with lower initiation pressure and greater complexity compared with H2O and supercritical CO2. Preliminary results confirm the potential of using LN2 fracturing to improve the stimulation effect of shale reservoirs.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Energy & Fuels
Jie Bai, Xiao-Qiong Wang, Hong-Kui Ge, Hu Meng, Ye-Qun Wen
Summary: Unconventional reservoirs often contain weak surfaces such as faults, laminae, and natural fractures, which can greatly improve extraction efficiency when effectively activated and utilized. This study calculates the hydraulic fracturing-induced stress field and establishes a stability model for natural fractures. Parametric studies are conducted to investigate the impact of each parameter on fracture stability. The validity of the model is verified by comparing it with data from the X-well 150-155 formation in the Songliao Basin. The study suggests connecting natural fractures with hydraulic fractures and then activating the natural fractures to effectively utilize them and form a complex fracture network.
Article
Energy & Fuels
Mengjiao Cao, Yuan Li, Xuguang Song, Yesheng Chen, Linghui Sun, Xin Shi, Caili Dai, Bin Yuan
Summary: In this study, a novel carbon dots (CDs) nanofluid was developed to reduce injection pressure and improve oil recovery in unconventional reservoirs. The CDs nanofluid exhibited superior stability, dispersibility, and temperature/salinity resistance, and could modulate the properties of oil/rock and oil/water interfaces. By partially absorbing onto pore walls and solidifying the remaining oil film, the CDs nanofluid significantly reduced injection pressure and improved the efficiency of oil film stripping.
Article
Engineering, Geological
Dingdian Yan, Luanxiao Zhao, Yang Wang, Yonghao Zhang, Zhenjia Cai, Xuehang Song, Fengshou Zhang, Jianhua Geng
Summary: Heterogeneity is an inherent feature of subsurface rocks such as unconventional reservoir shales. Understanding the influence of heterogeneities on the mechanical response and failure behavior of these rocks is crucial in various fields. In this study, two heterogeneity indexes are proposed to quantitatively characterize the heterogeneity of mineralogical compositions in unconventional reservoir shales. The results show that the heterogeneity index significantly influences the mechanical properties and deformation behaviors of reservoir shales.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Kaixuan Qiu
Summary: Ninety percent of China's newly proven natural gas reservoirs are unconventional resources that can be developed using multi-stage fracturing horizontal well technology. This paper presents an improved practical analytical solution for unconventional gas reservoirs. By solving the material balance equation and using integration, a real-time domain solution of rate vs. pseudo-time can be directly obtained. Five numerical cases are used to validate the accuracy of the proposed analytical solution and the derived ratio of regular/irregular region pore volume is significant for evaluating the effect of hydraulic fracturing. A field example of a multi-fractured horizontal well in a tight gas reservoir is also provided for demonstration.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Economics
Christopher E. Clarke, Darrick T. N. Evensen
Summary: This research examines media portrayals of unconventional oil and gas development's (UOGD) economic and environmental impacts. It reveals that selective attention to media coverage of the impacts can influence issue attitudes. The study also finds that political ideology plays a role in driving such attention, and that the attention given to different types of impacts predicts public support for UOGD.
Article
Energy & Fuels
Ahmed Al-Yaseri, Ghazanfer Raza Abbasi, Nurudeen Yekeen, Fssiz Al-Shajalee, Ausama Giwelli, Quan Xie
Summary: The study revealed that cleaning agents can alter the wettability of rocks, with toluene recommended for water-wet rock and acetone for oil-wet rock. Heptane is suitable for modifying wettability of oil-wet cores. Air plasma is the only effective method for removing surface contamination and organic carbon from quartz substrates to avoid incorrect contact angle measurements.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Azim Kalantariasl, Isa Farhadi, Soosan Farzani, Alireza Keshavarz
Summary: Prediction of gas well deliverability is crucial for reservoir management. Conventional flow tests and single-point tests are commonly used methods for calculating well deliverability, but existing dimensionless inflow performance relationships (IPR) often fail to accurately predict well deliverability for some reservoir conditions. This study proposes a comprehensive dimensionless IPR correlation based on a wide range of reservoir data, which successfully predicts gas well deliverability from single-point test data. Validation using multi-point test data shows good agreement between predicted and calculated absolute open flow (AOF), and the new dimensionless IPR outperforms previous correlations in a variety of reservoir conditions, as confirmed by error analysis.
JOURNAL OF PETROLEUM EXPLORATION AND PRODUCTION TECHNOLOGY
(2022)
Review
Energy & Fuels
Nilanjan Pal, Xuan Zhang, Muhammad Ali, Ajay Mandal, Hussein Hoteit
Summary: This article reviews the technical advances, challenges, and applicability of CO2 thickeners, particularly for hydrocarbon recovery. Different types of thickeners, including binary co-polymers and small molecule compounds, have been investigated and show promise for CO2 thickening.
Article
Chemistry, Physical
Lingping Zeng, Alireza Keshavarz, Quan Xie, Stefan Iglauer
Summary: Underground hydrogen storage (UHS) has potential for large-scale storage, and carbonate reservoirs can play a significant role. However, there is limited research on the risks and uncertainties related to carbonate dissolution and hydrogen loss. This study used geochemical modeling to assess the potential of UHS in the Majiagou carbonate formation in China. The results indicate that carbonate reservoirs are suitable for seasonal hydrogen storage but may not be ideal for long-term storage.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
Behnaz Sami, Amin Azdarpour, Bizhan Honarvar, Moein Nabipour, Alireza Keshavarz
Summary: The use of green, eco-friendly, efficient, and sustainable surfactants for enhanced oil recovery (EOR) is crucial. A novel natural surfactant extracted from oat was found to be highly efficient and stable for EOR applications. Different salts were tested, and Na2CO3 showed the best compatibility and achieved the most significant reduction in interfacial tension (IFT). Core flooding tests demonstrated that using the natural surfactant with Na2CO3 as a tertiary recovery agent increased the oil recovery factor by 28.89%.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Energy & Fuels
Mehran Mirzavandi, Jagar A. Ali, Abbas Khaksar Manshad, Barham Majeed, Barham Sabir Mahmood, Amir H. Mohammadi, Stefan Iglauer, Alireza Keshavarz
Summary: Nanomaterials, specifically silica-graphene quantum dots (Si-GQDs), have been synthesized and dispersed in water to form nanofluids. These nanofluids exhibit significant reduction in interfacial tension and wettability alteration, leading to enhanced oil recovery from carbonate reservoirs. The experimental results show that the nanofluids formulated with 1000 ppm Si-GQDs in distilled water enable an additional 14.4% oil recovery due to the reduction in interfacial tension and contact angle.
Article
Energy & Fuels
Auby Baban, Mujahid Ali, Muhammad Arif, Alireza Keshavarz, Robert Amin, Stefan Iglauer
Summary: This study used NMR technology to analyze the wettability and CO2 trapping behavior of rocks, and found that organic acids have a significant impact on the wettability and CO2 trapping behavior of rocks. The results showed that organic acids reduce the amount of CO2 trapping, and CO2 mainly traps in meso- and micropores. This study is of great significance for the implementation of large-scale underground gas storage and enhanced oil recovery projects in carbonate reservoirs.
Article
Chemistry, Multidisciplinary
Darya Khan Bhutto, Abdul Majeed Shar, Ghazanfer Raza Abbasi, Ubedullah Ansari
Summary: Wettability is a critical parameter for the productivity of hydrocarbon reservoirs. However, there is limited knowledge about the wettability of Sembar shale formations in the Lower Indus Basin, Pakistan. This study investigates the wetting behavior of Sembar shale samples using contact angle measurements. The results reveal that Sembar shale exhibits mixed wetting behavior, which improves our understanding of the wettability of these shale formations.
Article
Energy & Fuels
Fatemah Alhamad, Rossen Sedev, Mujahid Ali, Muhammad Ali, Hussein Hoteit, Stefan Iglauer, Alireza Keshavarz
Summary: Hydrogen is expected to be a significant clean energy carrier, but the development of a hydrogen economy requires large-scale hydrogen storage. Different underground formations can be used for hydrogen storage, and wettability is an important factor in determining the containment security and storage capacity. This study investigates the use of a toxic dye, methyl orange, to alter the wettability of reservoirs for hydrogen geo-storage.
Article
Energy & Fuels
Hussein Rasool Abid, Aamir Hanif, Alireza Keshavarz, Jin Shang, Stefan Iglauer
Summary: This study compares the performance of Cu-metal-organic framework (MOF) HKUST-1 synthesized using conventional hydrothermal synthesis with its modified analogues HKUST-N and HKUST-Ca for CO2, CH4, and H2 adsorption. The results show that different synthesis strategies significantly impact the morphology and adsorption performance of the materials.
Article
Energy & Fuels
Mirhasan Hosseini, Muhammad Ali, Jalal Fahimpour, Alireza Keshavarz, Stefan Iglauer
Summary: Underground hydrogen storage (UHS) and CO2 geological storage (CGS) are essential for meeting energy demand and reducing greenhouse gases (GHGs). The calcite-fluid interfacial tension (Ycalcite-fluid) is crucial for gas storage in carbonate formations, but there is a lack of Ycalcite-fluid data in the literature. We theoretically calculated Ycalcite-fluid for calcite/H2/water and calcite/CO2/water systems, considering geological parameters like temperature, pressure, organic acid concentration, and salinity. The results showed that Ycalcite-gas decreased with pressure, salinity, and organic acid concentration but increased with temperature. Ycalcite-water slightly increased with organic acid concentration and salinity. Furthermore, Ycalcite-fluid values were higher for the H2/brine system compared to the CO2/brine system. This study provides a better understanding of wetting characteristics and enables further research on H2/CO2 storage in carbonate formations.
Correction
Energy & Fuels
Fatemah Alhammad, Rossen Sedev, Mujahid Ali, Muhammad Ali, Hussein Hoteit, Stefan Iglauer, Alireza Keshavarz
Article
Energy & Fuels
Mirhasan Hosseini, Faisal Ur Rahman Awan, Nilesh Kumar Jha, Alireza Keshavarz, Stefan Iglauer
Summary: In this study, the zeta potential of basaltic rocks in contact with aqueous NaCl solution was investigated under different conditions such as temperature, salinity, and pH. The results showed that the zeta potential was affected by temperature, salinity, and pH, contributing to a better understanding of the basalt-water-CO2 interactions and enhancing industrial applications.
Article
Chemistry, Multidisciplinary
Milad Norouzpour, Amin Azdarpour, Rafael M. Santos, Ali Esfandiarian, Moein Nabipour, Erfan Mohammadian, Abbas Khaksar Manshad, Alireza Keshavarz
Summary: The deposition of asphaltene and wax during oil production poses significant challenges. This study investigated the efficiency of different solvents in dissolving these solids, finding that xylene, toluene, gasoline, kerosene, and gas condensate were the most effective. Furthermore, asphaltene deposition inside the cores reduced permeability by 79-91%, but xylene, gasoline, and kerosene were able to restore damaged permeability effectively, particularly at an injection rate of 1 bbl/min.
Article
Energy & Fuels
Faisal Ur Rahman Awan, Mohsen Farrokhrouz, Hamed Akhondzadeh, Stefan Iglauer, Alireza Keshavarz
Summary: Coalbed methane reservoirs can be negatively impacted by the generation of coal fines during production, leading to irreversible damage to cleat conductivity. This study investigates the effect of coal fines on proppant conductivity through experiments considering salinity, pH, coal rank, and additives. The results show that the uniform distribution of coal fines within a proppant pack does not significantly affect conductivity compared to non-uniform distribution due to clogging and straining. Furthermore, anionic surfactants are found to effectively disperse coal fines. These findings have implications for optimizing proppant conductivity in coalbed methane reservoirs, particularly during the early water drainage phase.
GAS SCIENCE AND ENGINEERING
(2023)