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Keywords: amplitude
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Proceedings Papers

Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, June 23–26, 2019
Paper Number: ARMA-2019-0067
... Dynamics Shikotsu permeability rock permeability transient stress disturbance permeability change pore pressure disturbance axial stress disturbance stress disturbance amplitude Brodsky 1. INTRODUCTION Large earthquakes can cause persistent changes in the groundwater level in the near-field...
Proceedings Papers

Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, June 23–26, 2019
Paper Number: ARMA-2019-0354
... ABSTRACT: Ultrasonic wave measurements have been used as a remote and non-destructive method to monitor the changes in state of stress and slip initiation in rock joints. Although ultrasonic precursors in the form of maximum transmitted amplitude have been reported for gypsum and Indiana...
Proceedings Papers

Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, June 23–26, 2019
Paper Number: ARMA-2019-0366
... measurements allowed for the detection of crack initiation at the tip of the pre-existing flaw. The normalized wave amplitude was observed to decrease at initial loading stages because of micro-cracking followed by a sharp decrease in the rate of amplitude reduction due to tensile crack initiation. Digital...
Proceedings Papers

Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, June 23–26, 2019
Paper Number: ARMA-2019-0430
... use the intensity factor of the rock resonance to describe the resonance intensity to the excitation of the drill bit. Define the frequency ratio 0/ = 0 3 / (3 )k M AL = + . The amplitude-frequency characteristic curves of the rock response are obtained as Fig. 6. The abscissa is the ratio of...
Proceedings Papers

Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, June 23–26, 2019
Paper Number: ARMA-2019-0449
... discontinuity. The gypsum blocks had perfectly matched contact surfaces with a half-cycle sine wave profile that spanned the central third of the discontinuity, surrounded by planar surfaces. The amplitude of the half-cycle sine wave was varied and ranged between 2 to 10 times the height of the asperities...
Proceedings Papers

Paper presented at the 53rd U.S. Rock Mechanics/Geomechanics Symposium, June 23–26, 2019
Paper Number: ARMA-2019-1592
... fluctuation of the pressure curve. (3) Injection rate has an effect on the instance of crack initiation, while it hardly affects the whole fracturing process. (4) The amplitude of the acoustic emission is positively correlated with the pumping pressure, and the higher the breakdown pressure is, the greater...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-795
... international journal Signature subtraction method sandstone specimen specimen ssm technique Artificial Intelligence sandstone threshold Upstream Oil & Gas nonlinear Nonlinear Signal ultrasonic measurement loading transducer Johnson propagation amplitude Indicator hedayat Gosford...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-047
... acoustic emission cyclic injection amplitude perforation initiation pressure fracture injection pressure curve Injection Rate wellbore 1. INTRODUCTION With the large-scale development of unconventional reservoirs such as tight oil and gas, coal-bed gas and shale gas, the hydraulic fracturing is...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-1038
... Reservoir Characterization wave velocity Artificial Intelligence shear strength rock joint stick-slip cycle Masoumi shear displacement rate experiment displacement rate interface specimen shear stress Upstream Oil & Gas mechanism sandstone amplitude Gosford sandstone...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-1160
... a new cycle began, and this process was repeated up to the point of breakdown. The results indicate a reduction on breakdown pressure and maximum AE amplitude for the cases of progressive cyclic and uniform cyclic injection, compared to continuous injection, as well as in terms of absolute AE energy...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-1177
... variations in rate and state friction law parameters with changes in the sliding velocity and normal stress as well as changes in ultrasonic wave properties such as the transmitted amplitude and wave velocity. The variations in ultrasonic waves were monitored and compared during both velocity weakening and...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-174
... measured at the lower frequency domain characterizes the propagating of the Rayleigh wave. Wave profiles corresponding to the heat production is located at the lower frequency domain in the temperature signals. The measured amplitudes of elevated temperature are in order of 0.01 °C, which increases...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-432
..., amplitude, frequency, in-situ stress and fracture propagation direction on the maximum tensile stress at the tip of the fracture were studied, as well as the difficulty of opening and propagation of the fracture. The research results show that the maximum tensile stress increases with the increase of...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-447
... structure of coal with drilling fluids. Results show that a turning point of head longitudinal wave amplitude was observed in the curve of coal acoustic properties and for different drilling fluids, the turning point occurred at different time. This phenomenon may imply that significant change of coal...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-257
... and ultrasonic frequencies. Much larger dispersion of up to 150% was observed for Young's moduli. In static tests, non-elastic deformations increase with increasing stress change, resulting in a reduction of the rock stiffness. The largest stress-amplitude effects were observed for Opalinus Clay: the...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-691
... Stephansson experiment amplitude continuous injection hydraulic performance fluid injection laboratory breakdown pressure reduction injection Magnitude injection scheme geothermal reservoir zang seismic event monotonic injection fracture 1. INTRODUCTION Fluid injection into geological...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-1170
... rupture source inversion result inversion hypocenter amplitude asperity 1. INTRODUCTION Laboratory studies of controlled shear faults have been shown to exhibit earthquake-like acoustic emissions (AE) events in a variety of rock and polymer materials (e.g. McLaskey and Glaser, 2011). When...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-1204
...°, and 90° were fabricated to provide understanding of crosscoupling stiffness. Wave amplitudes were compared with 2D simulations of compressional and shear stress waves based on a Discontinuous Galerkin method. For normal incidence, wave conversions were observed for micro-crack inclinations greater...
Proceedings Papers

Paper presented at the 52nd U.S. Rock Mechanics/Geomechanics Symposium, June 17–20, 2018
Paper Number: ARMA-2018-1235
... zone clay mineral Upstream Oil & Gas structural geology acoustic emission porosity sample 460 peak frequency geoarchitected rock sample 470 Reservoir Characterization fracture network caprock amplitude microstructural control shale macroscopic behavior thicker material fracture...
Proceedings Papers

Paper presented at the 51st U.S. Rock Mechanics/Geomechanics Symposium, June 25–28, 2017
Paper Number: ARMA-2017-0411
... waves impinged on the crack plane at normal incidence. The amplitude of the transmitted waves did not change significantly with shear crack initiation. However, shear to compressional wave conversions occurred when a shear crack was initiated, roughly at 76% of the load detected with DIC. The wave...

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