Article
Geochemistry & Geophysics
Tingxue Jiang, Haitao Wang, Xiaobing Bian, Daobing Wang, Jun Zhou, Bo Yu
Summary: Carbonate formations in unconventional reservoirs have complex storage space structures and are highly heterogeneous. Acid fracturing of carbonate reservoirs involves complicated mechanical mechanisms between hydraulic fractures and vugs. Through numerical simulations using a finite element model, we studied the impacts of injection rate, fluid viscosity, leakoff behavior, and natural fracture approaching angle on acid fracturing. Based on the results, we provided recommendations for optimal acid fracturing treatments to enhance fracture conductivity.
Article
Chemistry, Multidisciplinary
Jiecheng Song, Jianjun Liu, Rui Song, Yujia Song
Summary: This study investigates the effects of effective stress on permeability and gas production in fractured deep tight sandstone reservoirs. Laboratory tests and numerical simulations are conducted to analyze the influences of pore pressure and geo-stress. The results show that the increase in effective stress leads to a decrease in permeability and affects gas production. The proposed coupled seepage-geomechanical model considering permeability stress-sensitivity proves to be more accurate in historical gas production prediction.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Petroleum
Ye Tian, Chi Zhang, Zhengdong Lei, Xiaolong Yin, Hossein Kazemi, Yu-Shu Wu
Summary: An improved multicomponent diffusion model for fractured reservoirs was proposed to better quantify the transport processes across the fracture/matrix interface. The model was validated with diffusion experiments and showed better match with a fine-grid model compared to the double-porosity model. The simulation of a gas huff 'n' puff well demonstrated that including diffusion can affect the performance, especially for gas recovery and oil rate.
Article
Energy & Fuels
Lingling Yan, Quanwen Liu, Xuefen Liu
Summary: This paper proposes a method to model the cavities and fractures separately in fractured-vuggy carbonate reservoirs. The cavity model is generated by seismic resampling, and the attribute model is simulated and generated using inverted porosity and dynamic/static data constraints. Deterministic and random fracture modeling methods are used for large-scale and small-scale fractures, respectively. The cavity model and fracture attributes model are integrated to establish a geological model of fracture-cavity reservoirs. The method achieves credible simulation results in well drilling.
Article
Computer Science, Interdisciplinary Applications
Chao Zhang, Jianxin Fu, Yu Wang
Summary: The authors aimed to study the strength failure and cracking behavior of fractured rock under unilateral unloading. They found that prefabricated cracks and unilateral unloading conditions not only deteriorate the mechanical strength but also have significant differences in failure modes. Furthermore, the authors discovered that the model failure mode under unilateral loading conditions is obviously distinct from that in triaxial loading.
ENGINEERING COMPUTATIONS
(2023)
Article
Engineering, Geological
Lijun Liu, Zhaoqin Huang, Jun Yao, Qinghua Lei, Yuan Di, Yu-Shu Wu, Kai Zhang, Shiti Cui
Summary: Modeling the behavior of fractured and karstified porous media subject to coupled hydro-mechanical conditions is challenging due to the co-existence of porous media flow, fracture flow, and free flow. Cavities hinder water breakthrough while highly conductive fractures may facilitate water migration.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Energy & Fuels
Xiaolong Guo, Bin Yan, Juyi Zeng, Guangzhi Zhang, Lin Li, You Zhou, Rui Yang
Summary: The study developed a novel Bayesian elastic impedance variation with an angle and azimuth inversion approach for directly estimating the fluid indicator in fractured carbonate reservoirs. The method allows for reasonable estimation of reservoir parameters with relatively high accuracy, reliable indicating the presence of fractured gas-bearing reservoirs.
Article
Energy & Fuels
Zhengxiao Xu, Zhaomin Li, Shiti Cui, Binfei Li, Danqi Chen, Qifeng Zhang, Lei Zheng, Maen M. Husein
Summary: Deep fractured vuggy reservoirs are characterized by complex structures and strong heterogeneity. Foam flooding can improve oil recovery. Using a microetched physical model, foam stability and flow characteristics were assessed, and the EOR mechanism was analyzed.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Mathematics, Interdisciplinary Applications
Mustafa Mudhafar Shawkat, Abdul Rahim Bin Risal, Noor J. Mahdi, Ziauddin Safari, Maryam H. Naser, Ahmed W. Al Zand
Summary: Naturally fractured reservoirs pose challenges due to tectonic movements that increase fractures' permeability and conductivity. The instability of these properties affects fluid flow, causing problems during fluid transfer and production. This study introduced new machine learning models to predict fracture properties in reservoirs and highlighted the importance of computer-aided analysis for fractured reservoirs. The research demonstrated the effectiveness of the models and emphasized the need for execution techniques, such as artificial crack creation, to minimize hydrocarbon losses.
Article
Energy & Fuels
Yang Xuewen, Wang Rujun, Deng Xingliang, Li Shiyin, Zhang Hui, Yao Chao
Summary: Based on the analysis of geological characteristics and division of reservoir units, this study established physical models and conducted physical simulations to investigate the water flooding mechanism in the fault-controlled fracture-cavity carbonate reservoir under complex flow state. A mathematical model of fault-controlled carbonate reservoir with coexisting seepage and free flow was established, and pilot water injection tests were conducted to evaluate its effects on enhancing oil recovery. The results show that the fault-controlled fracture-cavity carbonate reservoir units can be divided into three types, and the mathematical model can quantitatively describe the fluid flow law in the fracture-cavity body.
PETROLEUM EXPLORATION AND DEVELOPMENT
(2022)
Article
Energy & Fuels
Boyi Xia
Summary: This paper establishes a two-phase seepage model of oil and gas in fractured carbonate reservoirs considering stress sensitivity and solves the model accurately and efficiently using a hybrid solution method. The results show that stress sensitivity affects the permeability of fractures and fluid seepage resistance, which seriously affects the production of oil wells.
FRONTIERS IN ENERGY RESEARCH
(2022)
Article
Energy & Fuels
Leidy Laura Alvarez, Leonardo Jose do Nascimento Guimaraes, Igor Fernandes Gomes, Leila Beserra, Leonardo Cabral Pereira, Tiago Siqueira de Miranda, Bruno Maciel, Jose Antonio Barbosa
Summary: The impact of fracture topology on shape factor and equivalent permeability is significant, especially showing higher hydraulic connectivity (f) values in synthetic scenarios. Numerical simulations show that analytical methods are not efficient for estimating equivalent permeability of fractured medium.
Article
Energy & Fuels
Li Yong, Deng Xiaojuan, Ning Chaozhong, Wang Qi, Cui Shiti, Zhang Qi, Wan Xiaoguo
Summary: The Ordovician fracture-vug carbonate reservoirs in Tarim Basin are characterized by developed vugs, caves, and fractures. The use of static seismic data for quantitative characterization of these reservoirs leads to significant uncertainty. This study proposes a novel technique that combines dynamic and static data to improve the accuracy of reservoir characterization by considering key influencing factors. The technique utilizes dynamic analysis methods such as well testing, production rate transient analysis, dynamic reserve evaluation, and dynamic connectivity evaluation to understand the reservoir. These understandings are used to constrain the inversion of seismic wave impedance, leading to improved relationships between wave impedance and porosity, fracture-vug morphology determination, and calculation of dynamic reserves. The method provides more accurate characterization results and has been successfully applied in Tarim Basin.
PETROLEUM EXPLORATION AND DEVELOPMENT
(2022)
Article
Environmental Sciences
Sanbai Li, Zhijiang Kang, Yun Zhang
Summary: This study proposes a novel workflow to investigate complex flow behaviors and remaining oil distribution in fractured-vuggy reservoirs based on outcrop information. The study uses a refined geological model and numerical simulations to explore the impacts of cave and fracture permeability as well as the position of natural water bodies on oil production performance. The results show that fracture permeability is more significant in determining oil recovery, and the position of natural water bodies can greatly affect oil recovery.
Article
Geosciences, Multidisciplinary
Cayo C. C. Pontes, Francisco H. R. Bezerra, Giovanni Bertotti, Vincenzo La Bruna, Philippe Audra, Jo De Waele, Augusto S. Auler, Fabrizio Balsamo, Stephan De Hoop, Luca Pisani
Summary: This study focused on the development of caves in carbonate units, investigating the roles of fractures and folds in the formation of karst conduits and flow pathways in carbonate reservoirs. The conduit shape, typically ellipsoidal in cross-section, reflects tectonic features and textural variations, with carbonate layers containing pyrite and low detritic mineral contents being favorable flow pathways. The development of the karst system was found to be related to fracture corridors formed along fold hinges, contributing to the formation of super-K zones.
JOURNAL OF STRUCTURAL GEOLOGY
(2021)
Article
Energy & Fuels
Jianmeng Sun, Ping Feng, Peng Chi, Weichao Yan
Summary: Through experiments and numerical simulations, it is found that pore structure parameters of tight sandstone have a significant influence on the electrical properties. Constructing a saturation model can improve the calculation accuracy.
Article
Energy & Fuels
Naser Golsanami, Bin Gong, Sajjad Negahban
Summary: Gas-lift dual gradient drilling with oil-based drilling fluid is investigated in this study. Comparisons are made between different models to evaluate the PVT behavior and optimize the gas flow rate. The existing Standing model has errors in assessing the PVT behavior and is not recommended, while the new models provide more accurate results for mixture evaluation and optimization.
Article
Thermodynamics
Naser Golsanami, Madusanka N. Jayasuriya, Weichao Yan, Shanilka G. Fernando, Xuefeng Liu, Likai Cui, Xuepeng Zhang, Qamar Yasin, Huaimin Dong, Xu Dong
Summary: This study provides a detailed quantitative characterization of clays in hydrocarbon reservoirs using deep learning and SEM images, and investigates the impact of clays on reservoir fluid flow. The results show that clays can significantly reduce reservoir porosity and permeability, shedding new light on the detailed impacts of clay minerals on reservoir quality.
Article
Acoustics
Xuepeng Zhang, Yujing Jiang, Yue Cai, Xin Li, Naser Golsanami, Xiao Wang, Jian Hao, Ningbo Li, Fabo Wu, Xiaohan Wang
Summary: Stochastic medium (SM) theory is a practical method for ground settlement prediction, but its solution process is complicated. In this study, a simplified analytical solution based on the SM theory is developed to predict ground movement induced by tunneling, and a method to estimate the parameters is proposed. The accuracy of the simplified method is validated by comparing the results with those obtained by the SM theory and measured data. The empirical comparisons demonstrate that the simplified method can provide a more reasonable prediction for ground movement induced by tunneling.
SHOCK AND VIBRATION
(2022)
Article
Energy & Fuels
Bin Gong, Ruiqi Zhang, Tianwei Sun, Yujing Jiang, Naser Golsanami, Yanlong Li, Shanilka G. Fernando, Madusanka N. Jayasuriya
Summary: This study analyzes the deformation, slope stability, and sand production during methane hydrate exploitation through numerical simulations. The results show that increasing loading and decompression amplitudes lead to increased deformation degree and distribution, elevated pore water pressure, larger methane hydrate regeneration and dissociation areas. Additionally, sand production always starts from the upper and bottom sections of the methane hydrate-bearing sediments layer near the wellbore and increases with mining time.
Article
Energy & Fuels
Qamar Yasin, Mariusz Majdanski, Rizwan Sarwar Awan, Naser Golsanami
Summary: Hydraulic fracturing has become increasingly common in enhanced geothermal systems. Evaluating the fracability of geothermal reservoirs is challenging and requires considering multiple parameters. This study proposes an improved fracability index model that incorporates various parameters to assess rock fracability. The model was validated using well logs and seismic data, demonstrating its effectiveness in evaluating fracability in geothermal and shale reservoirs.
Article
Energy & Fuels
Huaimin Dong, Jianmeng Sun, Muhammad Arif, Yihuai Zhang, Weichao Yan, Stefan Iglauer, Naser Golsanami
Summary: Gas hydrate reservoirs in the Muli area of China have complex lithology, high hardness, developed micro-fractures, and low porosity-permeability. This study combines digital rock technology with field-scale well-logging data to analyze the conductivity mechanism and identify the causes of the observed low resistivity. The findings provide fundamental information for accurate interpretation of key well-logging data and improving gas hydrate reservoir exploitation.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Bin Gong, Ruijie Ye, Ruiqi Zhang, Naser Golsanami, Yujing Jiang, Dingrui Guo, Sajjad Negahban
Summary: Studying the failure mechanism of methane hydrate specimens is important for methane hydrate exploitation. Previous studies mainly focused on the macro or micromechanical response, while this study explored the mechanical response mechanism based on energy evolution. The numerical model of methane hydrate-bearing sediments was constructed and validated using laboratory tests. The simulation results qualitatively described the mechanical properties of the sediments and provided insights into deformation and failure mechanisms.
Article
Energy & Fuels
Huaimin Dong, Xin Zeng, Dalin Zhou, Jinjiang Zhu, Naser Golsanami, Jianmeng Sun, Yihuai Zhang
Summary: This study aims to characterize Langmuir's volume and Langmuir's pressure more effectively using well-logging data to evaluate the gas-bearing capacity of marine shales in the Wufeng-Longmaxi Formation in the southern Sichuan Basin, China. The influencing factors of shale conductivity were analyzed, and it was found that the factors affecting conductivity from strongest to weakest are conductive organic matter, thin low-resistivity layer, clay mineral, pore water, and pyrite.
JOURNAL OF ENERGY ENGINEERING
(2023)
Article
Engineering, Chemical
Suogui Shang, Qiangyong Gao, Yunjiang Cui, Peichun Wang, Zhang Zhang, Yadong Yuan, Weichao Yan, Peng Chi
Summary: We proposed a low-cost and high-efficiency workflow for simulating the electrical properties of rocks under high-pressure and high-temperature conditions. This method accurately predicts the electrical characteristics of rocks and plays a key role in water saturation prediction.
Article
Energy & Fuels
Qamar Yasin, Ali Gholami, Mariusz Majdanski, Bo Liu, Naser Golsanami
Summary: The geologic structure plays a decisive role in controlling fluid flow in geothermal systems. Seismic data can provide high-resolution images of complex structures, but it is challenging to detect the characteristics of fault edges in deep-buried and structurally complex areas. In this study, an intelligent workflow based on structure-oriented filtering and sensitive seismic attributes is proposed to characterize fault edges and fractures in geothermal reservoirs.
Article
Energy & Fuels
Behzad Saberali, Naser Golsanami, Kai Zhang, Bin Gong, Mehdi Ostadhassan
Summary: Intelligent surrogate models are important tools in reservoir simulation, and their efficiency depends on the quality of the data source. The current study uses a hybrid data source based on finite difference and streamline data, which speeds up database preparation and improves model training efficiency. The introduced surrogate model has been validated and shown satisfactory results, making it applicable in other reservoirs and gas exploitation from natural gas hydrate reservoirs in China.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Mechanics
Behzad Saberali, Kai Zhang, Naser Golsanami
Summary: This study introduces a data-driven proxy modeling approach based on deep learning algorithms, which can determine the location of the injected water front in real-time. By minimizing the use of data extracted from numerical simulators and relying only on commonly available field data, the proposed proxy models successfully simulated breakthrough time and water arrival time in new blind scenarios.
INTERNATIONAL JOURNAL OF COMPUTATIONAL FLUID DYNAMICS
(2022)
