Article
Geosciences, Multidisciplinary
Yuke Liu, Chao Yang, Jianfeng Wang, Yongqiang Xiong, Ping'an Peng
Summary: This study compares two different shale samples to understand the mineralogical and microstructural control on water softening and creep deformation mechanisms in shale. The results show that shale with different mineral constitutes and microstructures exhibit differences in hydration process, which have different effects on the mechanical properties of shale.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Energy & Fuels
Yu Suo, Yan-Jie Zhao, Xiao-Fei Fu, Wen-Yuan He, Zhe-Jun Pan
Summary: This paper focuses on studying the fracture characteristics of shale samples with different pre-crack angles when immersed in different types of drilling fluids using the SCB test. The research findings showed that as the pre-crack angle increases, the fracture toughness and effective fracture toughness of Mode I fractures decrease continuously, while the fracture toughness of Mode II fractures gradually increases. The impact of drilling fluids on the fracture toughness of shale samples is in the following order: water-based drilling fluid > alcohol-based drilling fluid > oil-based drilling fluid. The length of the fracture process zone (FPZ) decreased with the increase of the pre-crack angle, and the FPZ length under different drilling fluid immersion shows varying degrees of enlargement. These findings could be useful in optimizing drilling fluid selection and fracture stimulation design in shale formations.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Article
Energy & Fuels
Michael K. Kostner, Ariele Zanfei, Jacopo C. Alberizzi, Massimiliano Renzi, Maurizio Righetti, Andrea Menapace
Summary: This study presents a methodology for selecting pumps-as-turbines (PaTs) in water distribution networks to minimize leakage losses and maximize energy recovery. A novel dynamic control algorithm and digital hydraulic model are developed. The methodology is applied to a real test case, improving the sustainability and energy efficiency of a mountainous water distribution network.
Article
Thermodynamics
Chongyang Wang, Dongming Zhang, Chenxi Liu, Yisha Pan, Zhigang Jiang, Beichen Yu, Yun Lin
Summary: True triaxial loading-unloading tests were conducted on natural and water-saturated shale, and the deformation and seepage characteristics were analyzed. The stress-strain curve of the water-saturated sample was not smooth, with noticeable volume expansion and changes in water flow. Water saturation and pressure affected the deformation characteristics and ductility of the sample.
Article
Mechanics
Kewang Cao, Liqiang Ma, Yu Wu, A. J. S. (Sam) Spearing, Naseer M. Khan, S. Hussain, Faheem Ur Rehman
Summary: This paper conducts infrared radiation observation experiments on dry and water saturated sandstone, studies the mechanical properties and infrared radiation characteristics during the fracture process of rocks, and establishes a rock constitutive model based on infrared radiation. The results show that water saturation weakens the mechanical properties of rocks but increases infrared radiation, and changes the failure mode of rocks. The established rock constitutive model can be used for stress prediction in both dry and saturated rocks.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Chemistry, Physical
Liu Yang, Yuting Mao, Duo Yang, Zhenchuan Han, Sheng Li, Jianchao Cai, Manchao He
Summary: In this study, nanoindentation tests were conducted on the surface of shale to propose a novel micro-brittleness index. By exploring the distribution characteristics of the brittleness index on the shale surface and the variation laws between mineral and brittleness index, the research revealed the brittleness features of shale and the heterogeneity on its surface. The results showed that the dimensionless brittleness index involved parameters such as indentation irreversible deformation, elastic modulus, hardness, and fracture toughness.
Article
Geochemistry & Geophysics
Fanzhen Meng, Louis Ngai Yuen Wong, Tianyang Guo
Summary: Rough fault surfaces play a dominant role in determining the mode of sliding. Stick-slip behavior occurs on all rough fractures during sliding, with stress drops and fault gouges increasing with normal stress. Micro-damage on post-shear surfaces includes powder-sized gouge, micro-cracks, and grain edge wear, increasing with normal stress. Different fault types have little discernible effect on stress drop. The study contributes to understanding the mechanics of dynamic geohazards associated with shear failure on rough faults or fracture surfaces.
Article
Engineering, Environmental
Baicun Yang, Lei Xue, Yongting Duan
Summary: A better understanding of energy evolution during brittle failure of hard rock is crucial for safe excavation, rockburst phenomena, and earthquake mechanisms. This study analyzes the mechanical behavior of rock during crack propagation based on Griffith's theory and investigates the conversion and distribution of elastic strain energy. Experimental tests using a novel setup provide reliable results and reveal the evolution characteristics of energies during brittle failure of hard rock, which may contribute to the mitigation and prevention of rock-induced disasters.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Engineering, Multidisciplinary
Jichen Zhong, Jiao Wang, Xiangyu Li, Xihua Chu
Summary: Understanding the failure mechanisms of shale-like brittle materials is crucial for engineering safety. This research reconstructed a discrete element model that reflects the real rock properties and failure modes of shale specimens with different bedding angles. It revealed the relationship between micro-crack numbers and macroscopic stress, as well as analyzed the relative movement between deformed blocks. The model can predict the mechanical behavior of brittle rock and guide the application of shale-like brittle materials.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Geochemistry & Geophysics
Heying Ding, Fuquan Song, Xiao Hu, Yeheng Sun, Weiyao Zhu
Summary: In this study, a non-Newtonian fluid model is established to analyze the flow characteristics of confined liquid in micro- and nanopores, revealing the nonlinear seepage law of water in micro- and nanochannels and tight reservoirs. Experimental verification of the non-Newtonian flow model is conducted.
Article
Geosciences, Multidisciplinary
Wentao Ban, Qingchun Yu
Summary: A numerical model for simulating methane transport and adsorption in crushed shale has been developed and calibrated using experimental data. The model shows that the strength of methane's diffusion ability is reflected in the methane free concentration in shale. The diffusion behavior can be divided into three stages during the adsorption-diffusion process, with the middle stage accounting for a significant portion of the process. Furthermore, the variation in diffusion coefficient (D) along the radial axis can be divided into two regions, with the horizontal area decreasing as adsorption-diffusion proceeds.
NATURAL RESOURCES RESEARCH
(2023)
Article
Engineering, Geological
Jianming He, Lekan Olatayo Afolagboye, Bo Zheng, Tianqiao Mao, Yanfang Wu, Guanfang Li, Shouding Li, Xiao Li
Summary: Increasing the strain rate can shorten the response time of shale and modify its stress-strain curves. Additionally, the strength and elastic modulus of shale generally increase with increasing strain rate, and the failure mode changes from shearing failure to a combination of tensile split and shearing failure.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Mechanical
Milos Pjevic, Mihajlo Popovic, Ljubodrag Tanovic
Summary: This paper conducted a detailed experimental analysis on the effect of tool tip radius and cutting speed on the micro-cutting mechanism of Plavi tok marble. It was found that the plastic deformation mode can be achieved in processing Plavi tok marble, and the range of plastic deformation zone is influenced by the tool tip radius and cutting speed. The intensity of lateral/radial destruction in the brittle fracturing mode was also directly dependent on the processing conditions.
SURFACE TOPOGRAPHY-METROLOGY AND PROPERTIES
(2021)
Article
Engineering, Mechanical
Xiong Zhang, Xiaoshuang Li, Yuehua Liu, Wei Liu, Qihang Li, Lin Li
Summary: Analyzing the crack propagation and failure mode of shale reservoirs is essential for hydraulic fracturing. In this study, uniaxial compression tests were conducted to examine the crack initiation and propagation of shale with double fissures of different inclination angles. The results showed that as the inclination angle of fissures increased, the peak strength and strain of shale increased, the initiation stress increased, and tensile-shear failure became the dominant failure mode.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Zhaofei Chu, Zhijun Wu, Zhiyang Wang, Lei Weng, Quansheng Liu, Lifeng Fan
Summary: The study found that the anisotropy of specimens significantly increases during creep, with a 30% difference in axial and lateral P-wave velocities at the onset of tertiary creep. Tensile cracks dominate the transient creep stage and the early part of the steady creep stage, while shear cracks dominate thereafter. The porosities of specimens increase with loading stages, with greater increments in porosity corresponding to small pores than those corresponding to large pores for all creep stages. Specimens with different degrees of creep damage exhibit greater deformability, with significant changes in short-term and creep mechanical parameters, except for uniaxial strength.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Geochemistry & Geophysics
Fanbao Meng, Xingfu Li, Patrick Baud, Teng-fong Wong
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Engineering, Multidisciplinary
Chaodong Tan, Wei Yan, Qing Tang, Hua Wu, Hongguang Bu, Said Juma Kambi, Jiankang Liu
MATHEMATICAL PROBLEMS IN ENGINEERING
(2020)
Article
Engineering, Geological
Fanbao Meng, Xingfu Li, Patrick Baud, Teng-Fong Wong
Summary: The study showed that bedding anisotropy significantly influences the effective stress coefficient for permeability, but has little effect on the coefficient for pore volume change. With the closure of preexisting microcracks, the effective stress coefficients for permeability in stage II were typically larger than in stage I.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Hao Chen, Hongkui Ge, Xiaoqiong Wang, Jianbo Wang, Shan Wu
Summary: The matrix permeability of shale reservoirs is very low, requiring massive volume fracturing during well completion to form a complex crack network. Effective stimulated reservoir volume (ESRV) is crucial for developing shale reservoirs, determined mainly by stimulated reservoir volume (SRV) and permeability increase. Microseismic monitoring is commonly used in the field to evaluate the stimulation effect, but the relationship between microseismic parameters and permeability has not been studied. Experimentation on Longmaxi shale samples showed that crack propagation and connectivity are critical factors affecting permeability, with cracks starting to propagate steadily and permeability increasing rapidly at 30-50% of the uniaxial compressive strength (UCS). AE characteristics can be used to identify the percolation threshold, which is crucial for understanding the relationship between microseismic parameters and permeability.
Article
Energy & Fuels
Wei Yan, Said Juma Kambi, Xin Huang, Hai Lin, Hailong Liu, Jingen Deng
Summary: This paper introduces an innovative method for determining the shallow soil resistance strength recovery factor, based on field data from the Equatorial Guinea bay, which shows a lower soil strength recovery factor compared to the Gulf of Mexico. The study recommends specific conductor setting depths for different well set-up periods, highlighting the importance of considering factors such as wellhead landed load in determining the conductor setting depth.
Article
Multidisciplinary Sciences
Senlin Luo, Hongkui Ge, Jianbo Wang, Wei Zhou, Yinghao Shen, Pengyu Liu, Jiantong Liu
Summary: The results indicate that the strength and crack shapes of conglomerates are relatively complex due to the common influence of cementation strength and gravel content.
ROYAL SOCIETY OPEN SCIENCE
(2021)
Article
Engineering, Geological
Wei Zhou, Guoxin Shi, Jianbo Wang, Jiantong Liu, Ning Xu, Pengyu Liu
Summary: In this study, a double torsion experiment was conducted to simulate the propagation of tensile fractures during hydraulic fracturing. The influence of bedding planes on fracture toughness, morphology, and propagation rate in shale and tight sandstone was investigated. The results indicate that the angle between bedding and pre-cut plane, as well as the difference in micromechanical properties of adjacent bedding planes, are crucial in determining whether hydraulic fractures can penetrate or spread along a bedding plane.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Energy & Fuels
Kongyang Wang, Jingen Deng, Wei Yan, Dickson Muchiri Nguu, Qiwu Yin, Shengsong Huang
Summary: This study establishes a quantitative method to describe casing deformation and categorizes it into concave and elliptical types. By comparing field and initial casing sections, the main cause of concave and eccentric ellipse casing deformations is determined to be fault slip.
Article
Geochemistry & Geophysics
Wei Yan, Guangyao Leng, Wenbo Li, Tao Wu, Mustajab Safarov, Jean P. E. Amboulou Ndessabeka, Keyu Meng
Summary: This study investigates the application of supercritical carbon dioxide (SC-CO2) fracturing technology in shale reservoirs. The experiments reveal the different reactions of shale samples to SC-CO2 and the variation of permeability and porosity during the fracturing process. The findings have significant implications for the efficient exploitation of shale oil reservoirs.
Article
Energy & Fuels
Wei Yan, Xin Huang, Nguu Dickson Muchiri, Han Cao
Summary: This study investigates the subcritical crack growth behavior of sandstone and shale samples under different conditions and finds that the presence of clay minerals is the main reason for the difference in behavior. Deionized water shows better improvement in subcritical crack growth, while slick water can better promote complex fracture propagation.
ENERGY SCIENCE & ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Wei Yan, Zelin Ma, Zhi Wang, Jingru Zhang, Kepei Li, Lei Wen, Chen Li, Xiaohui Jiang, Zhengxian Xu
Summary: This study investigates the localized corrosion mechanism of Q125 casing steel in residual acid solution with Mannich base type inhibitors during oil reservoir acidizing process. The corrosion behavior and inhibition efficiency of Q125 casing steel in fresh acid and residual acid solution with and without the Mannich base type inhibitor were studied. The decrease in inhibitor molecular coverage on the substrate surface under residual acid conditions promotes the occurrence of local corrosion. The presence of FeCO3 may hinder the adsorption of inhibitor molecules on the substrate surface, leading to pitting corrosion.
Article
Materials Science, Multidisciplinary
Jianfeng Liu, Minghui Li, Mengqi He, Zelin Ma, Kepei Li, Ling Wang, Guotao Li, Liguo Zhou, Shaohui Zhang, Wei Yan
Summary: The effect of chromium content on the corrosion resistance of carbon steel was evaluated by investigating the corrosion behavior of 1Cr and N80 steels under different CO2 partial pressure and temperature conditions. The results showed that N80 carbon steel exhibited serious pitting corrosion at medium temperature and low CO2 partial pressure, while 1Cr steel showed mesa corrosion dominated by local corrosion characteristics at high temperature and high CO2 partial pressure. The corrosion resistance of carbon steel and 1Cr steel was influenced by the corrosion environment and the formation process, compactness, and integrity characteristics of the product film.
Article
Energy & Fuels
Guangyao Leng, Wei Yan, Fuli Li, Bin Wang, Guangyu Yuan, Chengcai Chu, Yakai Li, Chenhao Gao
Summary: This study investigated the application of deep profile control technology to address the issue of oil recovery in sandstone reservoirs with varying permeability. Rheological tests, injection and plugging capacity experiments, and core flooding experiments were conducted to study the properties and mechanisms of modified starch gel and polymer gel. The results showed that the modified starch gel had better injection and plugging properties, resulting in improved oil displacement and sweep efficiency.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Xiaoping Ding, Wei Yan, Fargalla Mandella Ali Margan, Lingzhan Zou, Hong Li, Yulin Dou, Chaodong Tan
Summary: Cluster well is a new concept that can significantly improve the economic efficiency of well pad drilling in the petroleum industry. This paper proposes a numerical model to optimize well type/trajectory and pad deployment during cluster drilling, considering the impact of pad deployment on well type optimization and trajectory optimization.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
Article
Energy & Fuels
Wei Yan, Fuli Li, Guangyao Leng, Houdong Wang, Zelin Ma, Bowen Yun, Xiaorong Li, Jingen Deng
Summary: Sand production is a common problem in oil and gas field development, especially in weakly consolidated sandstone reservoirs. Mechanical sand control screens are commonly used, but they can suffer from erosion wear and premature failure due to sand-containing production fluid. This study developed an experimental device to simulate screen erosion damage caused by downhole sand flow. The experimental results showed that screen erosion mass loss was positively correlated with sand fluid velocity, sand concentration, median sand particle size, and erosion time. A comprehensive sand screen erosion prediction model was established, accurately predicting the screen's effective life in the field.
GEOENERGY SCIENCE AND ENGINEERING
(2023)
