... parameters (corner frequency and low-frequency spectral plateau) were determined for each AE event by fitting the Brune Omega-squared model to the detected AE signals. Seismic parameters such as seismic moment, source radius stress drop, and seismic energy were determined after incorporating the focal...

... in the field. Creep experiments were conducted on double-flawed prismatic Barre granite specimen in the laboratory under uniaxial compression to investigate the temporal and spatial evolution of the AE events during the primary, secondary and tertiary stages of creep. Results illustrated that brittle creep...

... facies plane ae sensor porous sandstone porous material calcite geological subdiscipline strength sensor nf-b interface sample united states government europe government carbonate mineral central image failure test calcite nodule interface dudley ae event cross section imaging strain...

... stephansson ae event injection hf experiment monotonic injection breakdown pressure fracture injection hydraulically fractured permeability ae activity ARMA 21 1064 A Comparative Study of Monotonic and Cyclic Injection Hydraulic Fracturing in Dry Tight Rocks Under Triaxial Stress Goyal, S...

... developed. By evaluating the time-variation of the source mechanisms of the AE events produced, it was noted that the number of AE events were spread-out throughout the specimen rather than concentrated near the flaws. This is interpreted to be a result of pore pressures diffusing through a larger area...

... the fracturing processes. At present, the number of AE events and the spatial distribution of AE locations are the two main factors considered in the evaluation of fracturing effect. A large number of AE events and a wide spatial distribution of AE locations often indicate a better fracturing effect. However...

... of deformation in the relaxation stages. As the strain level for relaxation increased, the stress dropped and correspondingly the number of AE events increased. The temporal analysis of the different cracking processes detected through AE and DIC revealed the higher contribution of tensile cracks in relaxation...

..., controlled pore pressure, and acoustic emission (AE) measurements. These studies provide valuable insights into the seismic and aseismic behavior of fault gouge coupled with fluid. friction ae event fluid-saturated gouge geophysical research upstream oil & gas fluid injection seismicity...

... of the Montney shale lithology compared to more brittle granitic specimens used in many previous studies, and the reverberatory character of the recorded waveforms, AE seismicity was relatively sparse (600 events) and only a small fraction (about 6%) of AE events could be located. Nevertheless, the hydraulic...

... number specimen heat-treated temperature AE event fracture mechanics characteristic ARMA 19 120 An Experimental Study on the Fracture Mechanics Characteristics of Heat-treated Hot Dry Rock Samples Under Different Loading Rates Wang, Daobing and Yu, Bo Beijing Key Laboratory of Pipeline Critical...

.... boreholes) networks or underground are limited to frequencies up to a few kilohertz. Therefore, small AE events are often not considered for stability assessment and interpretation of geomechanical conditions of the rock. In the higher frequency range of about 1 kHz up to 200 kHz special piezoelectric AE...

... and propagation of hydraulically-induced fractures under uniaxial and biaxial loading conditions, a very limited number of experimental studies investigate the effect of triaxial loading conditions on fracture initiation and propagation. hydraulic fracturing prefabricated flaw AE event fluid pressure...

... process of hydraulic fracturing using acoustic emission (AE). Experimental results show that the location of small few AE events along BP near the wellbore and stable injection pressure indicated the fracturing fluid leaking into the dilated BP under low injection rate (= 10 mL/min). In this case the SRV...

... ABSTRACT: Temporal and spatial acoustic emission (AE) event analysis, 3D fracture networks construction obtained from X-Ray CT images and thin section studies of the five tested specimens on isotropic pegmatite (PGR) and anisotropic migmatitic gneiss (VGN) samples obtained from ONKALO nuclear...

... on a set of 6 transducers throughout a laboratory hydraulic fracturing experiment. The number of waves, and subsequently the number of located AE events, make structures determined within dense point clouds of AE data difficult to interpret. Previous work in this area used several methodologies...

... of a MST test. Measurements were made on a weakly consolidated Miocene sandstone. Less than 2% of total number of AE events were recorded up to the MSM suggesting that minimal plastic strain has occurred, and the yield surface has not been approached. In contrast, for the MCS, 80% of AE events are observed...

... and could be detected around weak BPs far away from the wellbore before HF initiation. When the fracturing fluid slowly leaked into the BPs, the injection pressure remained stable and AE activity became low. Only a few AE events with low amplitude were located along the BP near the wellbore. Numerous shear...

... recorded. Approximately 50% and 25% of these events were locatable using at least 8 and 10 consistent P- and S-wave onsets, respectively. A cluster analysis found a big planar cluster with 142 AE events. We studied source mechanism and moment tensors of these clustered AE events using clear discernible...

... of the effective pressure law to borehole deformation. Located AE events coincide with post-test observations of damage and fracture locations. Comparison of AE behavior between the experiments with pore pressure show that breakouts develop prior to peak stress, and continued loading drives damage further...

... ABSTRACT: Here, a shear-tensile crack (STC) model is presented as suitable for Acoustic Emission (AE) events and compared to a traditional MT (Moment Tensor) approach. Experimental data was obtained from a uniaxial compression test performed on a Westerly Granite (WG) specimen using a 14...