Acoustic emission characteristics in hydraulic fracturing of stratified rocks: A laboratory study

Jiang, Zhizhong; Li, Quangui; Hu, Qianting; Liang, Yunpei; Xu, Yangcheng; Liu, Le; Wu, Xiaobing; Li, Xuelong; Wang, Xiaoguang; Hu, Lianxi; Ling, Faping

doi:10.1016/j.powtec.2020.05.050

Cited by 46 publications

(13 citation statements)

References 35 publications

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“…According to the acoustic emission count (cumulative count) and energy (cumulative energy) in the process of rock failure, we studied the degree of occurrence and development of cracks in the rock to through failure and the intensity of accompanying acoustic emission events (Guo and Wong, 2020;Jiang et al, 2020;Meng et al, 2021). Here, we list the test results of 60 °bedding specimens as an example.…”

Section: Characteristics Of Acoustic Emission During Rock Sample Fail...mentioning

confidence: 99%

Energy Evolution and Acoustic Emission Characteristics of Uniaxial Compression Failure of Anchored Layered Sandstone

Zhao

Feng

et al. 2022

Front. Earth Sci.

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To study the energy evolution and acoustic emission characteristics of layered sandstone under anchorage in the process of deformation and failure, the sandstone samples from Chuxiong Yi Autonomous Prefecture, Yunnan Province were selected for uniaxial compression testing. The energy evolution in the process of sandstone failure and the spatial fractal characteristics of acoustic emission events in the process of deformation and failure were investigated. Research results show that anchoring can make layered sandstone store more energy, the stored energy first increases, then decreases with the increase of bedding angle; the B value of sandstone under anchorage is generally higher than that of unanchored sandstone in the whole deformation and failure process, and the continuous decline in B value can be used to indicate a precursor to instability and failure; under the action of anchoring, the D value of sandstone (its fractal dimension) also increases, then decreases with the increase of bedding angle. The D value changes within [2, 3]. At a given bedding angle, the D value of anchored sandstone is greater than that of unanchored sandstone, the D value of 30° anchored sandstone increased the most (by 12.33%); the maximum D value occurred in 45° anchored sandstone (reaching 2.72) and the spatial distribution of acoustic emission events and damage of sandstone under anchorage is also more uniform; under increasing stress, the number of acoustic emission events is less widely distributed in the early stage and more densely distributed in the later stage. The growth rate of the D value varies across different peak stress ranges, which is more significant under the action of anchorage. The acoustic emission event counts grow evenly and slowly in the space, and the toughness of sandstone is improved to a certain extent under the action of anchorage.

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Section: Characteristics Of Acoustic Emission During Rock Sample Fail...mentioning

confidence: 99%

Energy Evolution and Acoustic Emission Characteristics of Uniaxial Compression Failure of Anchored Layered Sandstone

Zhao

Feng

et al. 2022

Front. Earth Sci.

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“…For discrete events, the RA‐AF method has been widely applied to classify the types of fractures (Aggelis, 2011; Ohtsu, 2011). The RA is the ratio of the rise time to the amplitude, and AF is the ratio of counts to the duration (Aggelis, 2011; Jiang et al., 2020). Furthermore, to study the failure types of rock fractures, the AE‐signal‐based method was used with a moment tensor analysis to identify fracture types (Manthei et al., 2001).…”

Section: Introductionmentioning

confidence: 99%

Identifying the Types of Loading Mode for Rock Fracture via Convolutional Neural Networks

Zhang

Huang

et al. 2022

JGR Solid Earth

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“…In addition, an experimental study was conducted to study liquid nitrogen-induced rock/coal failures under true triaxial stress conditions in order to investigate fracture propagation behaviors under in-situ geological conditions with liquid nitrogen injections. Many scholars have investigated the seismic response of naturally fractured coal to stress and hydraulic fracturing, with an emphasis on identifying the temporal and spatial behaviors of fractures using the active acoustic-monitoring technique (Qin et al, 2018;Zhang et al, 2018;Jiang et al, 2020;Cao et al, 2021;Li et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Fracture Propagation Characteristics of Hydraulic Fracturing in Multiple Coal Seams, Eastern Yunnan, China

et al. 2022

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As a reservoir reconstruction technology, hydraulic fracturing is a key method to improve the production of coalbed methane (CBM) wells. The CBM reservoir in eastern Yunnan, an important CBM exploration and development zone in China, is characterized by multiple thin coal seams. Compared to the fracturing of the single-layer coal seam, the combined seam fracturing technology is more difficult and complex. To study the fracture propagation characteristics and influencing factors of hydraulic fracturing in multiple coal seams, taking No. 9 and No. 13 coal seams as the research objects, the fracturing process was numerically simulated by using the finite element method and ANSYS software in this work. Based on the mathematical model of low permeable coal-rock mass, a two-dimensional hydraulic fracture model was established. In addition, the fracture geometries of combined seam fracturing were studied quantitatively. The results indicate that although No. 9 coal and No. 13 coal seams have similar rock mechanical properties, the propagation process and final geometry of a fracture are different. The reliability of the simulation results is verified by the comparison of experimental parameters and field investigation. The results prove the feasibility of combined seam fracturing in eastern Yunnan. The high Young’s modulus and thickness of the coal seam make the fracture geometry longer, but the fracture height is smaller. The low Young’s modulus, high Poisson’s ratio, and thickness of the No. 13 coal seam result in an increase in the length and height of the No. 9 coal seam. The increase in Young’s modulus of interlayer inhibits the propagation of fractures, while the high thickness and low Poisson’s ratio of interlayers facilitate the extension of the length and inhibit the extension of the height. This work provides a case reference for combined seam fracturing of coal reservoirs and has practical significance for the development of CBM characterized by multiple coal seams in eastern Yunnan.

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Acoustic emission characteristics in hydraulic fracturing of stratified rocks: A laboratory study

Cited by 46 publications

References 35 publications

Energy Evolution and Acoustic Emission Characteristics of Uniaxial Compression Failure of Anchored Layered Sandstone

Energy Evolution and Acoustic Emission Characteristics of Uniaxial Compression Failure of Anchored Layered Sandstone

Identifying the Types of Loading Mode for Rock Fracture via Convolutional Neural Networks

Numerical Simulation of Fracture Propagation Characteristics of Hydraulic Fracturing in Multiple Coal Seams, Eastern Yunnan, China

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