Article
Energy & Fuels
Hui Liu, Xinwei Liao, Xuefeng Tang, Zhiming Chen, Xiaoliang Zhao, JianDong Zou
Summary: A well test model based on the embedded discrete-fracture method shows advantages in computational performance over the stripe-fracture model. Sensitivity analysis is conducted to study the impacts of complex fracture networks, and the results show that optimizing fracture properties can influence the flow regimes of the well significantly.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Geological
Meiyu Li, Guowei Ma, Tuo Li, Yun Chen, Huidong Wang
Summary: In this study, an equivalent discontinuum analysis (EDA) method is proposed to deal with complexly fractured rock masses, which effectively maintains stress variability and displacement discontinuity while improving computational efficiency.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Engineering, Geological
Yanyan Li, Wei Hu, Siyu Wei, Lihui Li, Zhihong Zhang, Shengyuan Song
Summary: Preexisting discontinuities have a significant impact on fracture complexity in unconventional reservoirs. They act as barriers for fracture growth, resulting in smaller fracture area and higher fluid pressure for fracture extension. Joints play a more significant role in reducing fracture complexity compared to beddings.
ENGINEERING GEOLOGY
(2022)
Article
Environmental Sciences
Zitong Zhou, Delphine Roubinet, Daniel M. Tartakovsky
Summary: A method for inferring fracture density and fractal dimension of fractured rocks from thermal experiments data is presented. This method shows that fracture density can be well constrained by data, while fractal dimension is harder to determine. Adding nonuniform prior information related to fracture network connectivity improves the inference of fractal dimension parameter.
WATER RESOURCES RESEARCH
(2021)
Article
Engineering, Geological
Amirhossein Kamali, Ahmad Ghassemi, Dharmendra Kumar
Summary: An advanced numerical model is developed to investigate stimulation in naturally-fractured rocks. The model reveals that hydraulic fractures experience pressure drop upon intersection with natural fractures and may propagate in other directions. Simultaneous interaction with multiple natural fractures and/or stress barriers results in complex hydraulic fracture geometries.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Vedad Tojaga, T. Christian Gasser, Artem Kulachenko, Soren Ostlund, Adnan Ibrahimbegovic
Summary: This study introduces a three-dimensional geometrically nonlinear Reissner beam theory for modeling failure in structures and discusses its finite element implementation. The theory considers cracks through displacement discontinuities and incorporates three modes of fracture inside an element. By eliminating nodeless degrees of freedom and using an alternating minimization algorithm, a positive definite stiffness matrix is obtained. The performance of these new finite elements in numerical examples, including the fracture of random lattice structures, is demonstrated. Geometrical nonlinearity in the beam formulation is shown to be necessary for direct numerical simulations of fiber networks.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Thermodynamics
Junjie Shi, Linsong Cheng, Xiang Rao, Renyi Cao, Gaoling Liu
Summary: The paper presents a fully implicit solution model for coupling the oil-water two-phase temperature field and seepage field based on the embedded discrete fracture model method, improving calculation accuracy by deducing mass and heat transfer between local matrix and fracture grids using the boundary element method. The modified EDFM method proved to significantly enhance the calculation precision, especially in the temperature field, and is applicable to various examples of non-isothermal seepage in fractured reservoirs, demonstrating its efficiency and accuracy.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Computer Science, Interdisciplinary Applications
Ziyuan Cong, Yuwei Li, Yu Liu, Yonghui Xiao
Summary: This study proposed a stress numerical search method based on the maximum circumferential stress criterion to predict the fracture propagation angle in hydraulic fracturing. The method was found to be more consistent with real conditions and could be used to predict fracture propagation trajectories with different rock and construction parameters.
COMPUTERS AND GEOTECHNICS
(2021)
Article
Energy & Fuels
Chenhong Zhu, Jianguo Wang, Shuxun Sang, Wei Liang
Summary: This study proposes a multiscale convolutional neural network model (MsNet) to efficiently predict the equivalent permeability of a complex multiscale fracture network. The MsNet model performs better than other models on datasets with higher fracture density.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Engineering, Geological
Pengyu Wang, Shuhong Wang, Tianjiao Yang, Huan Liu, Ze Zhang
Summary: This paper proposes an effective tool for estimating fracture stiffness using XLiFE++ simulation and neural network method, and provides verification. The results show that this method can quickly determine the fracture interface stiffness.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2022)
Article
Mathematics, Applied
Qingdong Zeng, Long Bo, Lijun Liu, Xuelong Li, Jianmeng Sun, Zhaoqin Huang, Jun Yao
Summary: This paper presents an integrated study on intensive volume fracturing, including fracture propagation modeling and gas flow modeling, as well as correlation analysis to identify key controlling factors. The study employs the displacement discontinuity method (DDM) and the Picard iterative method to account for the interaction between hydraulic fracture and natural fracture in the fracture propagation model. The shale gas flow is considered using the embedded discrete fracture model (EDFM) to handle the flow in the fracture network. Numerical simulations are conducted to analyze the effects of various factors on stimulated fracture area, fractal dimension, and cumulative gas production.
APPLIED MATHEMATICS AND MECHANICS-ENGLISH EDITION
(2023)
Article
Optics
Allaparthi Venkata Satya Vithin, Ankur Vishnoi, Rajshekhar Gannavarpu
Summary: In this paper, a deep learning-based approach is proposed for direct estimation of phase derivatives in digital holographic interferometry. The robustness and practical utility of the proposed method are demonstrated through numerical simulations and experimental data.
Article
Thermodynamics
Ziyuan Cong, Yuwei Li, Yishan Pan, Bo Liu, Ying Shi, Jianguang Wei, Wei Li
Summary: In this paper, a CO2 foam fracturing fracture propagation model with temperature-pressure-phase coupling is established. The results show that improving the CO2 foam quality can significantly enhance the fracturing effect, and the fracture propagation is significantly affected by injection temperature.
Article
Computer Science, Interdisciplinary Applications
Tong Wang, Jun Yao
Summary: In this paper, an improved embedded discrete fracture model (EDFM) is proposed for numerical simulation in 3D complex fractured media. The improved EDFM, capable of simulating flows on 3D staggered overlapping unstructured matrix and fracture grids, is accompanied by efficient and robust domain connectivity algorithms. The performance of the algorithms is tested and compared with the traversal method using various cases of different scales. The improved EDFM is validated against discrete fracture model and traditional EDFM, demonstrating its capacity in real complex physical problems. The effects of grid type and resolution are also analyzed.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Computer Science, Artificial Intelligence
Nur Ezlin Zamri, Mohd. Asyraf Mansor, Mohd Shareduwan Mohd Kasihmuddin, Siti Syatirah Sidik, Alyaa Alway, Nurul Atiqah Romli, Yueling Guo, Siti Zulaikha Mohd Jamaludin
Summary: In this study, a hybrid logic mining model was proposed by combining the logic mining approach with the Modified Niche Genetic Algorithm. This model improves the generalizability and storage capacity of the retrieved induced logic. Various modifications were made to address other issues. Experimental results demonstrate that the proposed model outperforms baseline methods in terms of accuracy, precision, specificity, and correlation coefficient.
EXPERT SYSTEMS WITH APPLICATIONS
(2024)
Article
Energy & Fuels
Kerui Liu, James J. Sheng
Summary: This study investigates the role of clay swelling in shale fracturing by combining fracture generation, permeability change, and stress anisotropy. The results show that clay swelling impacts fracture generation through the generation of micro fractures and weakening the mechanical strength of shales. Moreover, clay swelling has a positive effect on the recovery of samples' permeability by increasing the width of existing fractures.
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2022)
Article
Thermodynamics
Zijian Wei, J. J. Sheng
Summary: The study investigates the permeability changes and their relationship with the microstructure in shale cores from the Chang 73 sub-member shale oil reservoir under different temperatures and stresses. The experimental results demonstrate that the porosity and permeability can be significantly increased when the temperature exceeds 400 degrees C. Furthermore, the coverage and connectivity of the fracture network are greatly improved. Kerogen pyrolysis is identified as the primary mechanism leading to remarkable improvements in microstructure and physical properties.
Article
Energy & Fuels
Ping Yue, Hongnan Yang, Guangming Yu, Zhipeng Yang, J. J. Sheng, Bingyi Jia
Summary: This paper investigates the risk of single well CO2 injection leakage and evaluates the leakage risk of CO2 injection buried wellbore in low-permeability reservoir in the Ordos Basin.
ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
(2022)
Article
Energy & Fuels
Xiaofei Xiong, J. J. Sheng, Xiaofeng Wu, Jianghua Qin
Summary: The study demonstrates that conducting foam-assisted nitrogen huff-n-puff experiments in fractured shale cores can inhibit gas channeling, extend gas channeling time, and expand the swept area, thereby helping to improve oil recovery in shale reservoirs.
Review
Geochemistry & Geophysics
Kerui Liu, Dangliang Wang, James J. Sheng, Jianfeng Li
Summary: The interaction between water and shale in shale development can have various effects on productivity and return on investment. Discrepancies exist regarding the impact of clay swelling on shale permeability, with some studies suggesting damage while others indicate enhancement. Factors such as clay swelling, mechanical properties reduction, and stress anisotropy contribute to the formation of induced fractures, which can either enhance or impair shale permeability.
Article
Energy & Fuels
Xiaoyu Hou, James J. Sheng
Summary: In this study, it was found that the Winsor type I surfactant solution with ultra-low interfacial tension (IFT) performed better than other relatively higher-IFT solutions in enhancing oil recovery in shale reservoirs. Anionic surfactants and Winsor type I surfactant solutions could alter the wettability to a water-wet condition and displace the oil from micropores and mesopores. The surfactant solutions changed the recovery patterns from capillary force-driven two-phase flow to diffusion and gravity-driven migration of microemulsions and emulsions.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Physical
Rui Liu, Yingxue Xu, Wanfen Pu, Peng Shi, Daijun Du, James J. Sheng, Huaisong Yong
Summary: This research focuses on improving the dispersion of graphene oxide (GO) to prepare a highly anisotropic GO material (GOC) that can disperse well in various organic solvents and maintain high dispersion stability in strong brine. The GOC can significantly reduce surface tension, generate water-in-oil Pickering emulsions with high water content, and exhibit liquid crystal behavior at the oil-water interface without external stimuli.
APPLIED SURFACE SCIENCE
(2022)
Article
Energy & Fuels
Zesen Peng, J. Sheng
Summary: In this study, the CO2 diffusion coefficient of shale under reservoir conditions was determined in the laboratory, and its contribution to enhanced oil recovery (EOR) during the huff-n-puff process was evaluated using a reservoir numerical model. The results showed that including CO2 diffusion in the model while reducing fracture spacing and increasing fracture half-length promoted the CO2 diffusion effect. Additionally, slower injection rates and shorter injection times were found to enhance the contribution of CO2 diffusion to EOR.
Article
Energy & Fuels
Rui Liu, Shi Gao, Qin Peng, Wanfen Pu, Peng Shi, Yinlang He, Tao Zhang, Daijun Du, James J. Sheng
Summary: The study investigates a new amphiphilic graphene oxide derivative, GOA, for chemical enhanced oil recovery. Experimental characterizations and molecular dynamics simulations demonstrate that GOA exhibits good dispersibility and stability in brine, lowering interfacial energy at the oil-water interface and potentially enhancing oil recovery.
Article
Energy & Fuels
Xiaoyu Hou, James J. Sheng
Summary: Experimental and simulation studies have shown mixed results on the effects of shut-in and interfacial tension (IFT) reduction in removing water blockage after hydraulic fracturing. This work studied the impact of shut-in and IFT reduction on water blockage and found that shut-in can decrease permeability due to water refill, while reducing IFT is beneficial for regained permeability ratio. However, emulsification should be avoided. The study also found that the residual water saturation is larger in micropores and mesopores, indicating that core damage mainly comes from these smaller pores.
Article
Energy & Fuels
Weiyu Tang, Zesen Peng, James J. Sheng
Summary: This study examines the application potential of CO2-based enhanced oil recovery (EOR) methods in shale reservoirs and proposes a method for carbon storage. By conducting fluid simulation and numerical simulation, it is proven that the huff-n-puff (HNP) method can significantly increase CO2 recovery, and the economic analysis takes into account the impact of oil prices and carbon taxes on development scenarios.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Review
Energy & Fuels
Xiaoyu Hou, James J. Sheng
Summary: With the development of the oil industry, improving oil recovery (IOR) technology is becoming more and more important, and nanoemulsions have attracted a lot of attention. However, the properties and characteristics of nanoemulsions are confusing, and the IOR mechanisms of nanoemulsions have not been systematically reviewed. This comprehensive review aims to clarify these problems and provide insights and directions for the further development of nanoemulsions in the oil and gas industries.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Zijian Wei, James J. Sheng
Summary: Thermal cracking in rocks can significantly increase permeability, which is crucial for enhancing oil recovery in ultra-low permeability reservoirs. In-situ thermal stimulation and real-time measurement were performed to evaluate the potential for thermally-induced permeability enhancement in tight sandstone and shale cores. The results showed that thermal cracks rapidly initiated and formed a multi-scale fracture network, leading to permeability improvement up to 11.23 and 29.82 times, respectively.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Wei-Yu Tang, James J. Sheng, Ting-Xue Jiang
Summary: CO2 huff-n-puff is a potential enhanced oil recovery method for tight reservoirs. The spatial distribution of oil saturation was analyzed using NMR method to understand the HNP mechanisms. The results show that soaking improves oil production and increased injection pressure gradient enhances oil recovery in the deep part of the reservoir.
Article
Energy & Fuels
Xiaoyu Hou, James J. Sheng
Summary: A novel spontaneous emulsification system with a low concentration of alkali was developed for enhanced oil recovery (EOR) in low-permeability reservoirs. Experimental results showed that the system could emulsify crude oil effectively and improve oil recovery efficiency.