Acoustic Emission Evolution and Hydraulic Fracture Morphology of Changning Shale Stressed to Failure at Different Injection Rates in the Laboratory

Zhang, Yongfa; Zhao, Yu; Zang, Arno; Long, Anfa

doi:10.1007/s00603-023-03586-8

Cited by 23 publications

(4 citation statements)

References 74 publications

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“…However, the real-time three-dimensional permeability evolution of the overall coal–rock combination during true triaxial fracturing was not assessed and should be further investigated. In addition, although the test results indicate that the penetrating fracturing can improve the permeability of coal measure formation, the geological environments of the deep coal seam is complicated, and the ScCO 2 fracturing techniques should be optimized considering the in situ stress and the mechanical properties of natural coal–rock combination. − More large-size true triaxial fracturing tests are needed to be conducted in the future, considering the different geological interfaces and in situ stress, to investigate the influence of these factors on the crack propagation across the interface and induced anisotropic permeability evolution of the reservoirs. , In addition, field fracturing tests should be conducted according to the experimental results to explore the fracturing technologies suitable for different geological conditions of the coal measurement reservoirs.…”

Section: Resultsmentioning

confidence: 99%

“…44−46 More large-size true triaxial fracturing tests are needed to be conducted in the future, considering the different geological interfaces and in situ stress, to investigate the influence of these factors on the crack propagation across the interface and induced anisotropic permeability evolution of the reservoirs. 47,48 In addition, field fracturing tests should be conducted according to the experimental results to explore the fracturing technologies suitable for different geological conditions of the coal measurement reservoirs.…”

Section: Crack Propagation Characteristicsmentioning

confidence: 99%

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Cracks Propagation and Permeability Enhancement Caused by Supercritical CO₂ and Water Fracturing in Natural Coal–Rock Combination

Wu,

Luo,

Chen

et al. 2024

Energy Fuels

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Coal-bed methane (CBM), shale gas, and tight sandstone gas are abundant in coal measure formations. In order to achieve the joint exploitation of the gas through multilayers, the penetrating fracturing, achieving crack propagation across different layer interfaces, was used to increase the overall permeability of coal measure formations. The true triaxial tests were conducted to investigate the crack propagation through the natural coal−rock combination with using supercritical CO 2 (ScCO 2 ) and hydraulic fracturing. The morphological characteristics of crack propagation within the coal after fracturing were analyzed. Meanwhile, the fracturing-induced anisotropic permeability within the natural coal−rock combination was explored. The main results showed that (1) compared with hydraulic fracturing, ScCO 2 fracturing is beneficial to the cracks crossing the interface into coal and forming a complex fracture network. (2) After hydraulic fracturing, the permeability parallel to and perpendicular to the bedding plane are 22.5 and 21.9 times higher than that before fracturing, respectively. Compared to hydraulic fracturing, the ScCO 2 fracturing induced a larger increase, 40.3 and 39.6 times, respectively. (3) The anisotropic ratio of the permeability parallel to and perpendicular to the bedding plane is 2.01, and after ScCO 2 and hydraulic fracturing, it becomes 2.05 and 2.15, respectively. In addition, both sides of the main crack (along the bedding plane) showed an evident increase in the permeability. The results indicate that ScCO 2 fracturing brings a larger permeability enhancement of the natural rock−rock combination compared to that of hydraulic fracturing.

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Section: Resultsmentioning

confidence: 99%

Section: Crack Propagation Characteristicsmentioning

confidence: 99%

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO₂ and Water Fracturing in Natural Coal–Rock Combination

Wu,

Luo,

Chen

et al. 2024

Energy Fuels

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“…The effectiveness of the hydraulic fracturing primarily depends on the extension of fractures. The deeper and wider the fracturing extend, and the better the control of fracturing height, the more effective the stimulation . However, accurately calculating the size of fracture networks in practical situations is challenging .…”

Section: Data Preparationmentioning

confidence: 99%

“…The deeper and wider the fracturing extend, and the better the control of fracturing height, the more effective the stimulation. 25 However, accurately calculating the size of fracture networks in practical situations is challenging. 26 From an engineering perspective, understanding the morphology of fracture extension allows for a accurate assessment of the construction effects.…”

Section: Pattern Classification Of the Hydraulicmentioning

confidence: 99%

Hybrid Deep Learning Approach for Hydraulic Fracture Morphology Diagnosis in Coalbed Methane Wells

Yang,

Gou,

Min

et al. 2024

Energy Fuels

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Accurately diagnosing hydraulic fracture morphology is crucial for coalbed methane (CBM) development and strategy formulation. However, achieving precise and efficient diagnosis of fracture morphology remains a challenge in complex geological and engineering environments. Therefore, this study proposes a hybrid deep learning method based on multivariate time series classification. In this method, the fracturing curve is compared to the "language" of the CBM reservoir, with fracture morphology representing the semantics of this "language". This method integrates a wavelet transform module and a deep encoder−decoder module. The wavelet transform module aims to reduce signal noise and enhance model robustness, while the deep encoder−decoder module extracts latent features from the fracturing curve. Integrating hydraulic fracture morphology recognition into a hybrid deep learning model composed of diverse deep neural networks tailored for specific predictive tasks maximizes the strengths of each network component. This approach was evaluated using real data from CBM blocks in Northern China, supported by ablation experiments, numerical simulations, and microseismic interpretation, demonstrating its effectiveness and applicability. In contrast to traditional time series deep learning models, this method enables more robust extraction of advanced temporal features and delivers high-precision predictions. This novel approach provides an effective solution for diagnosing hydraulic fracturing morphology and contributes to guiding refracturing.

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Permeability Evolution of Coal Seam Roof Sandstone Under Thermal Treatment

Bi,

Zheng,

Zhao

et al. 2023

Rock Mech Rock Eng

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Acoustic Emission Evolution and Hydraulic Fracture Morphology of Changning Shale Stressed to Failure at Different Injection Rates in the Laboratory

Cited by 23 publications

References 74 publications

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO₂ and Water Fracturing in Natural Coal–Rock Combination

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO₂ and Water Fracturing in Natural Coal–Rock Combination

Hybrid Deep Learning Approach for Hydraulic Fracture Morphology Diagnosis in Coalbed Methane Wells

Permeability Evolution of Coal Seam Roof Sandstone Under Thermal Treatment

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Acoustic Emission Evolution and Hydraulic Fracture Morphology of Changning Shale Stressed to Failure at Different Injection Rates in the Laboratory

Cited by 23 publications

References 74 publications

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO2 and Water Fracturing in Natural Coal–Rock Combination

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO2 and Water Fracturing in Natural Coal–Rock Combination

Hybrid Deep Learning Approach for Hydraulic Fracture Morphology Diagnosis in Coalbed Methane Wells

Permeability Evolution of Coal Seam Roof Sandstone Under Thermal Treatment

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Product

Resources

About

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO₂ and Water Fracturing in Natural Coal–Rock Combination

Cracks Propagation and Permeability Enhancement Caused by Supercritical CO₂ and Water Fracturing in Natural Coal–Rock Combination