Article
Energy & Fuels
Mahmoud Khadijeh, Alissar Yehya, Elsa Maalouf
Summary: This study analyzes the efficiency of hydraulic fracturing operations using numerical models and experimental studies. It finds that in vertically transversely isotropic (VTI) formations, the expansion of cracks is influenced by the degree of anisotropy. Additionally, cracks grow independently when the distance between cracks exceeds 12 m, and a planar propagation is observed for a distance above 20 m. The results also indicate that close cluster spacing leads to larger fractured area and resulting permeability. This work helps identify the optimal fracturing scenario for enhancing permeability in anisotropic unconventional reservoirs under different hydro-mechanical conditions.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Energy & Fuels
Yongzheng Cui, Ruizhong Jiang, Qiong Wang, Xiuwei Liu
Summary: This study presents an innovative model incorporating space variable and stress-sensitive fractures for the production of MFHW in shale, considering different transport mechanisms and conductivity patterns. The results show that different parameters such as space varying fractures and stress-sensitive coefficients have significant impacts on pressure drop and productivity. The model provides a more realistic simulation of gas flow in MFHW, aiding in the understanding of production dynamics in shale.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Energy & Fuels
Thomas Berard, Jean Desroches
Summary: This paper demonstrates the effectiveness of using borehole-wall images to document 3D geological structure away from the well, up to tens to hundreds of meters. By utilizing borehole structural geology, better modeling of geological conditions and improved horizontal well placement and hydraulic fracturing effects were achieved.
GEOMECHANICS FOR ENERGY AND THE ENVIRONMENT
(2021)
Article
Energy & Fuels
Yongzheng Cui, Ruizhong Jiang, Yihua Gao, Jingqi Lin
Summary: This study focused on developing a semi-analytical decline analysis model for a multi-wing fractured vertical well with partially propped fractures, considering different stress-sensitive effects. Systematic sensitivity analyses were conducted to investigate the influences of propped and un-propped fractures on production rate, and the flow flux and pressure distribution along the partially propped fractures were analyzed for the first time. The findings contribute to a better understanding of fracture flow mechanisms and can improve the development of tight resources.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Geological
Mahsa Sakha, Morteza Nejati, Thomas Driesner
Summary: This paper investigates the problem of hydraulic fracture initiation from an initially notch-free wellbore situated in an anisotropic host rock. The initiation pressure, initiation orientation, and initiation length characterize hydraulic fracture initiation in such conditions. The strength-based criterion captures only two of these parameters, while the evaluation of initiation length requires a mixed criterion approach. The study extends the mixed criterion formulation for isotropic rocks to include anisotropic material behavior and explores the interaction between material anisotropy and stress anisotropy in determining the break-down pressure, starter crack size, and orientation.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Multidisciplinary Sciences
Jingling Xu, Ruotao Wang, Ling Zan, Xiaoguang Wang, Jiaqing Huo
Summary: This study proposed an efficient method for identifying and characterizing fractures in tight sandstone reservoirs. By analyzing the log response characteristics and constructing logging eigenvalue and rock physical eigenvalue models, different fractures were accurately identified and characterized. This method is of great significance for the research of fine reservoir evaluation and fracture theory.
SCIENTIFIC REPORTS
(2022)
Article
Energy & Fuels
Cong Lu, Qijun Zeng, Jiaxing Liu, Zhenfu Ma, Xianzhen Shao, Lin Tang, Yanxia Huang, Guangqing Zhou, Xianbo Meng, Jiandong Wang, Jianchun Guo
Summary: In this study, a mathematical model of proppant embedding was established based on rock surface indentation experiment and Hertz contact theory. Shale spontaneous imbibition experiments were conducted to develop a mathematical model for hydration depth, and a proppant embedded mathematical model of rough fractures was built considering the elastic-elastoplastic-plastic whole-stage. The research provided insights into the laws of proppant embedding and offered a theoretical basis for shale reservoir fracturing design and fracture effectiveness analysis.
Article
Geosciences, Multidisciplinary
Iain de Jonge-Anderson, Jingsheng Ma, Xiaoyang Wu, Dorrik Stow, David Griffiths
Summary: The production performance of a shale reservoir is directly influenced by the geomechanical characteristics of the formation, with the complexity of shale properties making it difficult to identify ideal target intervals for horizontal wells. For the UK's most promising shale gas target, the Bowland Shale, traditional long horizontal wells may not be feasible due to geological complexities, leading to the exploration of shorter, stacked horizontal well drilling alternatives for different stratigraphic intervals. By creating geomechanical zones within the Bowland Shale and identifying optimal intervals for hydraulic fracturing, potential landing zones with low effective stress and high brittleness can limit vertical hydraulic fracture growth and reduce the risk of well interference.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Qinjie Liu, Qiang Fu, Ke Yang, Quanchao Wei, Huihu Liu, Haibo Wu
Summary: Based on a comprehensive analysis of wellbore characteristics, this study assessed the in-situ stress state of a shale reservoir in the Longmaxi formation in the Dingshan area, Southwestern China. Data from hydraulic fracturing, drilling-induced fractures, and in-situ core testing were used to determine the magnitude and direction of the maximum principal horizontal stress. The study also utilized hydraulic fracturing and cross-multipole array acoustic logging to assess the vertical variation of in-situ stress.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Thermodynamics
Chenyu Wang, Jiabo Geng, Dongming Zhang, Shujian Li, Xiaolei Wang, Qinglin Li
Summary: This study investigated the effect of drilling direction and hydraulic pressure on shale failure properties in hydraulic fracturing. The results showed that increasing hydraulic pressure led to a decrease in shale's tensile strength, absorbed energy, and crack deviation distance. High hydraulic pressure weakened shale's mechanical strength and facilitated the formation of hydraulic cracks. Additionally, the stability of shale's acoustic emission energy was analyzed, indicating the suitability of specific hydraulic fracturing technical conditions.
Article
Energy & Fuels
Yuan Wang, Liguo Zhong, Lei Zhang, Junpeng Zou
Summary: Based on the theories of mass conservation and CBM adsorption/desorption, this paper establishes a novel reservoir pressure model for CBM production and proposes CBM concentration and production models. The models are solved using the finite element method, and the reservoir pressure, gas concentration, and production characteristics are simulated for the Hunchun CBM field in Jilin province, China. The study shows that hydraulic fractures greatly reduce reservoir pressure and that the permeability sensitivity coefficient, R-pk, decreases logarithmically with distance from the extraction well. The findings provide valuable insights for the design of hydraulic fracturing wells and the evaluation of CBM production.
Article
Engineering, Mechanical
Justin Jordan Pidho, Yanbo Liang, Yuanfang Cheng, Chuanliang Yan
Summary: This study developed a model to capture micro-void nucleation with tensile and shear failure modes and present the interaction mechanism between propagating hydraulic fractures (HFs) and shale bedding planes (BPs) and natural fractures (NFs). The study demonstrated the influence of in situ stress contrast and cluster spacing on fracture complexity and shear opening at the intersection of HFs with BPs and NFs.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Geological
Yide Guo, Xibing Li, Linqi Huang
Summary: This study investigates the impact of spontaneous water imbibition on the dynamic tensile strength of shale discs. The results show that water imbibition weakens the tensile strength, except for discs with a bedding orientation of 90 degrees. The coupling effects of bedding orientation and loading rate on tensile strength are also examined. The rate-dependent failure mode is observed in discs with bedding orientations of 30 degrees, 45 degrees, and 60 degrees, and this phenomenon is exacerbated after water imbibition.
ENGINEERING GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Fuchun Tian, Yan Jin, Lin Shi, Ziyuan Cong, Yuwei Li
Summary: This study investigates the impact of fracturing main parameters on fracture propagation during hydraulic fracturing by establishing a fracture propagation model and proposing a simulation calculation method. The results demonstrate that the porosity and permeability of the rock matrix have a significant influence on leakage, while the natural fracture zone can change the propagation direction of the main fracture. In the same fracturing section, only some hydraulic fractures meet with natural fractures, leading to the formation of a T-shaped fracture network.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Energy & Fuels
Jiangfeng Cui, Guangyao Si
Summary: The study utilizes the finite difference method to conduct numerical simulation of micro-fractures in shale rocks, characterizing their impact through the concept of normalized equivalent permeability. It comprehensively investigates the effects of horizontal bedding fractures and vertical structural fractures on the anisotropic permeability of shale, providing valuable insights for enhancing oil/gas recovery in shale reservoirs.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2021)
Article
Thermodynamics
Nan Wei, Lihua Yin, Chao Li, Jinyuan Liu, Changjun Li, Yuanyuan Huang, Fanhua Zeng
Summary: This study proposes a hybrid method named CMLS to assess the complexity of natural gas consumption data, finding a significant relationship between forecasting performance and complexity level. In very hard cases, the daily natural gas consumption data is challenging to forecast accurately.
Article
Energy & Fuels
Yizhong Zhang, Bin Ju, Maolin Zhang, Chenchen Wang, Fanhua Zeng, Rongrong Hu, Long Yang
Summary: The study on salt precipitation in high-salinity shale reservoirs revealed a substantial reduction in porosity and absolute permeability, with a stronger impact on larger pores and throats, leading to the disruption of fluid flow channels and changes in pore size distribution. Results predict a decrease of about 20.4% in methane adsorption capacity due to salt precipitation, with the potential for even smaller adsorption capacity at higher temperatures.
Article
Energy & Fuels
Hongyang Wang, Farshid Torabi, Fanhua Zeng, Huiwen Xiao
Summary: Experimental studies on non-equilibrium solvent dissolution kinetics in a micromodel PVT system showed that the dissolution rate of spherical bubble was one order of magnitude higher than Taylor bubble due to larger contact area with oil. The feasibility of using the exponential relationship established from bubble-scale dissolution tests to simulate solvent dissolution behavior using a continuum-scale modeling technique was effectively proved by developing a reservoir simulator to determine dissolution-relevant parameters.
Article
Energy & Fuels
Chuan Xie, Yonghui Liu, Xiaoping Li, Guangbiao Wang, Qinghua Wang, Fanhua Zeng
Summary: A novel downhole bubble breaker was designed to mitigate the low efficiency of electrical submersible pumps (ESPs) under slug flow conditions. Computational and experimental studies were conducted to evaluate the efficiency and performance of the bubble breaker. The results showed that the optimal structure and parameters of the bubble breaker could effectively reduce the impact of bubbles and improve the ESP's performance.
JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Energy & Fuels
Chuan Xie, Xiaoping Li, Yonghui Liu, Fanhua (Bill) Zeng, Chengcheng Luo
Summary: This study tested and analyzed downhole chokes in both vertical and horizontal tubes, and found significant differences between the evaluation results for vertical and horizontal flow patterns. The downhole chokes changed the flow pattern downstream of the chokes and improved pressure stability. By comparing the results, the most accurate models for predicting different flow patterns were determined.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Bo Wang, Qiushi Zhang, Shanshan Yao, Fanhua Zeng
Summary: In this study, a semi-analytical model based on the discrete coordinate method was established to investigate the influence of secondary fractures on the transient pressure characteristics of multi-fractured horizontal wells. Sensitivity analysis showed that fracture parameters have varying impacts on the MFHW.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Energy & Fuels
Qiushi Zhang, Haoran Hu, Bo Wang, Yiming Chen, Fanhua Zeng, Cunlei Li
Summary: The study established a fracture growth model based on vertical fractured wells and solved using source function theory and boundary element method. The rationality of the model calculation method was verified, and the pressure change laws before and after fracture formation were analyzed.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Chemical
Chen Shen, Xiang Zhou, Binyang Zou, Bo Wang, Kewei Zhang, Fanhua Zeng
Summary: CO2-based cyclic solvent injection (CSI) processes can enhance heavy oil recovery. However, pure CO2 injection is not commercially feasible. By mixing CO2 and C3H8 with heavy oil, the performance of the CSI process can be improved. The experimental results show a positive correlation between pressure depletion rates and oil recovery factors, and the foamy oil flow phase can be divided into two zones.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2022)
Article
Engineering, Chemical
Binyang Zou, Wanfen Pu, Xiang Zhou, Daijun Du, Yan Shi, Wei Xia, Fanhua Zeng
Summary: This study investigates the feasibility and advantages of using nitrogen huff-n-puff in heavy oil reservoirs. The results show that nitrogen huff-n-puff can form stable foamy oil flow, enhance overall recovery, and achieve high early production with low cost.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
Article
Energy & Fuels
Jinyuan Liu, Shouxi Wang, Nan Wei, Yi Yang, Yihao Lv, Xu Wang, Fanhua Zeng
Summary: This paper proposes a three-layer neural network forecasting model that improves the weight optimization mechanism of the LSTM neural network to effectively forecast short-term natural gas consumption. It uses a CNN layer to extract features and improve computing efficiency, and an LSTM layer to overcome the defects of gradient disappearance and explosion. An ATT layer is employed to optimize weight assignment and highlight key sequences.
Article
Energy & Fuels
Jun Yang, Jing Zhao, Fanhua Zeng
Summary: Foam plays an important role in enhanced oil recovery in the petroleum industry. However, existing models for foam flow in porous media lack accuracy and reliability due to the empirical treatment of some parameters. This study proposes a novel mixed-sorting rule incorporated into an IPM-based foam propagation model, which successfully predicts the behavior characteristics of foam in porous media.
Article
Engineering, Chemical
Zeyu Lin, Xinqian Lu, Muhammad Imran, Kelvin (Kelly) D. Knorr, Fanhua Zeng
Summary: In this study, a large sand-pack model was used to simulate a real reservoir and investigate the viscous fingering phenomenon in radial flow. The experimental results agree with previous studies and show that increasing capillary number leads to more unstable interfaces and complicated finger structures. The analysis suggests that viscosity has a greater effect on viscous fingering compared to injection rate, and increasing the viscosity ratio can significantly decrease breakthrough time. In addition, it was found that there can be an additional pseudo-stable displacement stage in radial displacement.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2023)
Article
Energy & Fuels
Ze Li, Gao Li, Hongtao Li, Jinyuan Liu, Fanhua (Bill) Zeng
Summary: Shale-liquid interactions can cause shale swelling and damage, affecting the properties of shale. This study investigates the relationship between shale swelling and damage using experiments, computed tomography scanning, and numerical simulation. Results show that increasing shale swelling leads to significant shale damage and fracture expansion. The simulation confirms the importance of shale swelling in shale damage. Factors such as in-situ stress, injection pressure, and fracture network complexity influence shale damage.
Article
Green & Sustainable Science & Technology
Baoxin Zhang, Xuehai Fu, Yibing Wang, Zeyu Lin, Longjiang Fan, Fanhua Bill Zeng
Summary: This study analyzes the geochemical compositions of coalbed methane (CBM) and groundwater in the western Fukang area of the Southern Junggar Basin in China. It discovers that determining the genesis of CBM in mixed genesis gas (MGG) areas cannot rely on a single component. The study also proposes a novel approach for predicting CBM production based on geochemical compositions.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Energy & Fuels
Pin-Lu Cao, Hong-Yu Cao, Jin-E Cao, Cheng-Da Wen, Bao-Yi Chen, Shan-Shan Yao
Summary: In this study, numerical simulations were used to analyze the performance of large-diameter DTH hammers and a new hammer design was proposed to reduce air consumption rate. Field testing showed that the new hammer had a penetration rate 1.7 times faster than conventional mud drilling.
