Experimental study on ultrasonic velocity and anisotropy of tectonically deformed coal

Chen, Hongdong; Jiang, Bo; Chen, Tongjun; Xu, Shenglin; Zhu, Guanyu

doi:10.1016/j.coal.2017.06.003

Cited by 45 publications

(35 citation statements)

References 24 publications

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“…As shown in Figures 5(a) and 5(b), the V P of anthracite coal samples is about 1600-1800 m/s while the V S is within the interval of 800-1000 m/s. Compared with the previous research results [ [14][15][16][17][18][19][31][32][33], the ultrasonic velocity results of the coal samples in this study are within a reasonable range.…”

Section: Test Results and Discussionsupporting

confidence: 56%

“…where Test errors are inevitable due to the experimental method and human factors [16], which may influence the test results.…”

Section: Experimental Apparatus and Experimental Errormentioning

confidence: 99%

“…the abovementioned directional differences may be the inconsistency between the clays and the pore fractures of the coal [14][15][16][17][18][19].…”

Section: Geofluidsmentioning

confidence: 99%

“…Besides, the complex underground site conditions and various influence factors also increase the complexity of the issue under discussion. Therefore, many scholars have conducted long-term researches on the physical and mechanical properties of coal samples [12][13][14][15][16] and gained some important insights on elasticity. For example, the greater the density of the coal samples is, the larger the velocities (P-and S-waves) become [17].…”

Section: Introductionmentioning

confidence: 99%

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Experimental Study on the Effect of Gas Pressure on Ultrasonic Velocity and Anisotropy of Anthracite

et al. 2019

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To research the elasticity of gas-bearing coal fluid-solid two-phase medium with seismic exploration method is critical to the prevention of gas disasters. To investigate the elasticity, the ultrasonic elastic test of anthracite samples under different gas pressures was carried out and the ultrasonic velocity and anisotropy of the samples were analyzed in this study. The results show that the velocities (P- and S-waves) decrease in turn in the strike, dip, and vertical directions. However, a negative linear correlation is proved to exist between ultrasonic velocity and gas pressure. With the increase of gas pressure, the anisotropy degree of both the P-wave and the S-wave of the samples decreases but the declining degree of the P-wave is greater than that of the S-wave. In addition, the decrease in velocity and the anisotropy degree of the P-wave is greater than that of the S-wave, indicating that the P-wave is more sensitive to gas pressure changes in terms of velocity and its anisotropy degree.

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Section: Test Results and Discussionsupporting

confidence: 56%

“…where Test errors are inevitable due to the experimental method and human factors [16], which may influence the test results.…”

Section: Experimental Apparatus and Experimental Errormentioning

confidence: 99%

“…the abovementioned directional differences may be the inconsistency between the clays and the pore fractures of the coal [14][15][16][17][18][19].…”

Section: Geofluidsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Study on the Effect of Gas Pressure on Ultrasonic Velocity and Anisotropy of Anthracite

et al. 2019

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“…Reliable well-logging interpretation depends on a rock physics test. It has been testified that the static physical properties of mechanical strength [7,10], velocity [11,12], resistivity [13,14], elastic modulus [15] and pore-fracture system [16] change complicatedly with the type of TDC. A more consistent understanding of the increasing deformation degree of TDC can be obtained by means of decreasing density, sonic velocity, resistivity and strength.…”

Section: Introductionmentioning

confidence: 99%

Productivity Evaluation of Coalbed Methane Well with Geophysical Logging-Derived Tectonically Deformed Coal

et al. 2019

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Tectonically deformed coal (TDC) has a significant influence on coalbed methane recovery. Well-logging is a reliable and efficient way to predict the development of TDCs for understanding the role of TDC on the productivity of coalbed methane (CBM) wells. However, there has been insufficient research regarding both the static physical properties and dynamic invasion of mud-filtrate related to TDCs. Therefore, a new TDC-detecting approach using two indicators of the relative physical properties and fluid attributes was proposed. Through the data normalization and optimization of correlation coefficients and factor analysis, five logs were chosen to construct the two indicators, and three types of TDC were recognized: I—undeformed or cataclastic; II—granulated; and III—mylonitized. It was found out that the identification error rate decreased from 30% to 15%. Furthermore, the thickness ratio of a well-preserved coal layer derived from TDC interpretation was adopted to correlate the gas production of a coal seam. An application in the Hancheng block demonstrated that the thickness ratio of 60% is an explicit threshold value to distinguish between high-yield well (>1000 m3/d) and low-yield one (<750 m3/d). The development of granulated and mylonitized coals mainly exerts negative influence on CBM well production.

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Simulation of Effects of Incident Angles and Frequencies of Ultrasonic Waves on Wave Energy Propagation and Variation of Cleat Width Induced by Ultrasonic Waves

Qian

Xing

2021

Pure Appl. Geophys.

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Experimental study on ultrasonic velocity and anisotropy of tectonically deformed coal

Cited by 45 publications

References 24 publications

Experimental Study on the Effect of Gas Pressure on Ultrasonic Velocity and Anisotropy of Anthracite

Experimental Study on the Effect of Gas Pressure on Ultrasonic Velocity and Anisotropy of Anthracite

Productivity Evaluation of Coalbed Methane Well with Geophysical Logging-Derived Tectonically Deformed Coal

Simulation of Effects of Incident Angles and Frequencies of Ultrasonic Waves on Wave Energy Propagation and Variation of Cleat Width Induced by Ultrasonic Waves

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