Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 21 for “"microseismic events"”.
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Bayesian source inversion of microseismic events
… hydrofracture of gas and oil reservoirs, mining events and extraction of geothermal fluids. Source inversion is very sensitive to uncertainties in both the model and the data, especially for low magnitude, namely microseismic, events. Many of the uncertainties can be poorly quantified, and are …
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Automatic P-wave Picking of Microseismic Events in Underground Mines
This thesis investigates microseismic P-wave arrival time detection performance of automatic picking algorithms, as well as the handpicking performance of human experts. The data set used in this project was collected from Malmberget mine (LKAB, Sweden) and the handpicked P-wave arrivals were …
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B-Value Analysis of Microseismic Events Observed on Three Wellpads in the Horn River Basin
… analysis is carried out on a large dataset of microseismic events accumulated from over 300 stages during the hydraulic fracture treatment of three wellpads in the Horn River basin. This analysis is carried out on three different length scales: the single stage level, the level of the formation …
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Microseismic Monitoring of a Room and Pillar Retreat Coal Mine in Southwest Virginia
… rockmass behavior associated with the process. A microseismic monitoring system was installed in a retreat mine in Southwest Virginia to provide more information about the changing stress conditions created by retreating and ultimately reduce risk to miners. Microseismicity has been proven to be …
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An Analysis of Focal Parameters with Application to West Texas Micro-Earthquakes
Two types of seismic events related to hydrocarbon production have been extensively studied recently: microseismic events associated with hydraulic fracturing in unconventional reservoirs and induced seismicity associated with fluid extraction and wastewater injection in oil fields. This …
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Four-Dimensional Passive Velocity Tomography of a Longwall Panel
… for the study of rockbursts. Rockbursts are events that occur in underground mines as a result of excessive strain energy being stored in a rock mass and sometimes culminating in violent failure of the rock. Rockbursts often involve inundation of broken rock into open areas of the mine. They …
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Microseismic observations in the Ceres-Tulbagh aftershock zone, Western Cape, South Africa, and their tectonic implications
… of the 1969 Ceres earthquake. A total of 168 microseismic events could be located within the boundaries of the array, roughly 30 km x 40 km. Travel times of these events were used for coupled hypocenter-velocity inversion to produce a one dimensional velocity model with station corrections. …
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Sensor placement for microseismic event location
… intensity earthquakes that are referred to as microseismic events. Monitoring of microseismic events is useful in predicting and comprehending hazards, and in evaluating the overall performance of a mine design. A robust localization algorithm is used to estimate the source position of the …
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Applications of Double-Difference Tomography for a Deep Hard Rock Mine
… rock mine can be a precursor to ground failure events. Seismicity data can be used in double-difference tomography, which produce tomograms showing velocity distributions in the rock mass that can be used to infer relative stress of the rock mass. The data set used for the double-difference …
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Spatio-temporal microseismic analysis of the Woodford Shale, Canadian County, Oklahoma
Microseismicity provides data that can be used to monitor hydraulic fracture stimulation programs as well as to characterize the resulting hydraulic fractures. This is especially important in low permeability gas and oil shales, where the creation of additional permeability through these fracture …
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Monitoring microseismic activity in core samples encased in core flooding apparatus subjected to confining and pore pressures
… however, may be accompanied with an increase in microseismic activity. In order to better understand the causes of microseismic events detected during and after CO2 injection, a sensitive, reliable and consistent data acquisition system was developed in the present study for monitoring …
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Exploring subsurface ground water and geochemical rock interactions during drainage of a surface water reservoir in Switzerland
… of a nearby surface water reservoir induced microseismicity In the surrounding rocks. The GTS is a network of closely monitored tunnels and boreholes approx 300-500m below ground surface.Characterisation of background geochemical conditions over a two-year period consisted of a time series of …
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Applications of Continuous Wavelet Transform in Hydraulic Fracturing and Reservoir Management
… dynamic fracture event detection, microseismic event prediction, water hammer modeling, and inter-well connectivity for optimizing waterflooding operations. In fracture closure analysis, the study reviews established methods like the Nolte, tangent, and compliance methods, …
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Imaging the Soultz Enhanced Geothermal Reservoir using double-difference tomography and microseismic data
… methods. The stimulations produced over 12000 microseismic events of which we chose 8930 for further analysis. We obtained high accuracy cross-correlation differential times and then performed a double-difference tomographic inversion to jointly invert for velocity structure and event …
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Imaging a Hydraulically Fractured Bakken Shale Reservoir Using 4D-Tomography and Reverse VSP Techniques with Perforation Shot Sources
… where hydraulic fractures have penetrated and microseismic events can have uncertainties in their location and description. I propose the use of perforation shots to map regions where hydraulic stimulation was more effective using P- and SV-wave direct arrivals emitted by the shots. First, I …
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Investigation of the Pre to Post Peak Strength State and Behaviour of Confined Rock Masses Using Mine Induced Microseismicity
… occurs. Associated with this failure are microseismic events, which can be used to give an indication of the strength state of the rock mass. Based on an analogy to laboratory testing of intact rock and measurement of acoustic emissions, the microseismicity can be used to identify, …
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Geomechanical Reservoir Model Calibration and Uncertainty Assessment from Microseismic Data
… microearthquakes (MEQs). Triggering of the MEQ events has been linked to the pore pressure, temperature, and in-situ stress variations which result in crack initiation. The resulting clouds of micro-seismic events are believed to carry information about the underlying coupled flow, geomechanics, …
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Elastic time-reverse imaging and transmission tomography for microseismic and DAS VSP data
… that produce high-quality passive-source (e.g., microseismic) images or structural images of geological interfaces constructed using controlled-source energy (e.g., vibroseis truck or dynamite). Most existing wavefield migration and tomography techniques employed in the oil and gas industry are …
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Study of induced seismicity for reservoir characterization
… borehole seismic network. The majority of the events have a strike direction parallel with the major NE-SW faults in the region, and some events trend parallel with the NW-SE conjugate faults. The results are consistent with the in-situ well breakout measurements and the current knowledge of …
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Model Calibration and Performance Optimization Using Multiple-Point Geostatistics and Machine Learning Techniques
… probability maps, which can be derived from microseismic events, are also included in the modelling process to account for the variability in the extent of the induced and existing fracture networks within a stimulated reservoir volume near the primary hydraulic fractures. A sensitivity study …
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