A Passive Microseismic Monitoring Network at the Quest CCS Project

2017 ◽  
Author(s):  
V. Oropeza Bacci ◽  
S. O'Brien ◽  
M. Anderson ◽  
K. Dahlby ◽  
N. Henderson
Keyword(s):  
Monitoring Network ◽  
Microseismic Monitoring

scholarly journals Full-Waveform based methods for Microseismic Monitoring Operations: an Application to Natural and Induced Seismicity in the Hengill Geothermal Area, Iceland

2020 ◽  
Vol 54 ◽  
pp. 129-136
Author(s):  
Camilla Rossi ◽  
Francesco Grigoli ◽  
Simone Cesca ◽  
Sebastian Heimann ◽  
Paolo Gasperini ◽  
...  
Keyword(s):  
Power Plants ◽  
Tectonic Setting ◽  
Electrical Power ◽  
Monitoring Network ◽  
Microseismic Monitoring ◽  
Volcanic Area ◽  
Seismic Zone ◽  
Geothermal Area ◽  
Geothermal Systems ◽  
Full Waveform

Abstract. Geothermal systems in the Hengill volcanic area, SW Iceland, started to be exploited for electrical power and heat production since the late 1960s. Today the two largest operating geothermal power plants are located at Nesjavellir and Hellisheiði. This area is a complex tectonic and geothermal site, located at the triple junction between the Reykjanes Peninsula (RP), the Western Volcanic Zone (WVZ), and the South Iceland Seismic Zone (SISZ). The region is seismically highly active with several thousand earthquakes located yearly. The origin of such earthquakes may be either natural or anthropogenic. The analysis of microseismicity can provide useful information on natural active processes in tectonic, geothermal and volcanic environments as well as on physical mechanisms governing induced events. Here, we investigate the microseismicity occurring in Hengill area, using a very dense broadband seismic monitoring network deployed in Hellisheiði since November 2018, and apply sophisticated full-waveform based method for detection and location. Improved locations and first characterization indicate that it is possible to identify different types of microseismic clusters, which are associated with either production/injection or the tectonic setting of the geothermal area.

Estimating microseismic detectability of the surface-monitoring network using downhole-monitoring array

2018 ◽  
Vol 6 (3) ◽  
pp. SH107-SH115
Author(s):  
Paweł Wandycz ◽  
Eryk Święch ◽  
Leo Eisner ◽  
Andrzej Pasternacki ◽  
Denis Anikiev ◽  
...  
Keyword(s):  
Detection Threshold ◽  
Low Frequency ◽  
Monitoring Network ◽  
Microseismic Monitoring ◽  
Data Sets ◽  
Surface Monitoring ◽  
Microseismic Events ◽  
Downhole Array ◽  
Two Stages ◽  
Downhole Monitoring

We have analyzed microseismic monitoring data sets obtained from the surface and downhole-monitoring arrays recorded during the first experiment of hydraulic fracturing in Poland. Using the downhole-monitoring network, we were able to record and locate 844 microseismic events, including 10 perforation shots from six stages of the stimulation. We detected 2 perforation shots and no microseismic events using the surface array, which was operational only during the first two stages of the stimulation. To explain the poor detectability of the surface array, we analyzed the spectral content of the events from the downhole-monitoring array. We found that the detectability of the perforation shots on the surface array was consistent with the low-frequency part of the signal on the downhole recordings. Our observation is in agreement with the fact that microseismic events with low-frequency signal weaker than the two detected perforation shots were not detected by the surface-monitoring array. Using the low-frequency part of the spectra of the events recorded by the downhole array, we predicted the surface-array detection threshold. We found that some events from the later stages could have been detected if only the surface array had been operational during that time.

Technology Principle and Application of Microseismic Monitoring Rockburst

2014 ◽  
Vol 1010-1012 ◽  
pp. 1487-1493
Author(s):  
Xiao Jing Zhu ◽  
Yi Shan Pan ◽  
Zhi Tang
Keyword(s):  
Monitoring Network ◽  
Development Trend ◽  
Microseismic Monitoring ◽  
Vibration Energy ◽  
Actual Situation ◽  
Rock Stress ◽  
Focal Position ◽  
Frequency Maximum ◽  
Vibration Mechanism ◽  
Occurrence Regularity

In order to monitor and forecast rockburst, and analyze the source and magnitude,a set of microseismic monitoring rockburst technology was developed,combining with the actual situation in Dongtan coal mine.The technique used SOS microseismic monitoring system to determine failure points,record rockburst moments,the size of epicenter,the epicenter pressure drop and vibration mechanism,infer coal and rock stress state and destruction,and evaluate and monitor rockburst danger degree in accordance with changes of microseismic activities,focal position and activities tendency. The optimization microseismic monitoring network was layoutted in monitoring areas.The seismic geophone picked up microseismic signals and recorded in the rockburst figure,and the rockburst occurrence regularity and development trend were studied based on statistical analysis results of microseismic datas.Then by using VB6.0,the rockburst monitoring results were compounded in the mining drawing with concentration analysis.The rockburst events were statistical processed partitionedly to obtained vibration frequency,maximum vibration energy and total shock energy.The rockburst can be monitored and predicted through the rockburst events reflected by the datas.

Joint Focal Mechanism Inversion Using Downhole and Surface Monitoring at the Decatur, Illinois, CO2 Injection Site

2020 ◽  
Vol 110 (5) ◽  
pp. 2168-2187 ◽  
Author(s):  
Nadège Langet ◽  
Bettina Goertz-Allmann ◽  
Volker Oye ◽  
Robert A. Bauer ◽  
Sherilyn Williams-Stroud ◽  
...  
Keyword(s):  
Stress Field ◽  
Pore Pressure ◽  
Monitoring Network ◽  
Microseismic Monitoring ◽  
Fault Reactivation ◽  
Co2 Injection ◽  
Injection Point ◽  
Field Orientation ◽  
Fracture Pressure ◽  
East West

ABSTRACT The three-year CO2 injection period at the Illinois Basin - Decatur Project site (Decatur, Illinois, United States) produced a number of microseismic events distributed in very distinct spatiotemporal clusters with different orientations. Further characterization of the microseismicity encompasses the determination of the event source mechanisms. Initially, the microseismic monitoring network consisted solely of borehole sensors, but has been extended with surface sensors, thereby significantly improving the data coverage over the focal sphere. This article focuses on 23 events from the northernmost microseismic cluster (about 2 km from the injection point) and takes advantage of both, surface and downhole, recordings. The resulting strike-slip east–west-oriented focal planes are all consistent with the east–west orientation of the cluster in map view. The injection-related increase of pore pressure is far below the formation fracture pressure; however, small stress-field changes associated with the pore-pressure increase may reach as far as to the investigated cluster location. Monte Carlo modeling of the slip reactivation potential within this cluster showed that the observed maximum stress-field orientation of N068° is the optimum orientation for fault reactivation of the east–west-oriented cluster. Our results suggest that the east–west orientation of the investigated cluster is the main reason for its activation, even though the cluster is about 2 km away from the low-pressure injection point.

scholarly journals SOURCE LOCATION MECHANISM OF MICROSEISMIC MONITORING USING P-S WAVES AND ITS EFFECT ANALYSIS

10.6036/10370 ◽  
2022 ◽  
Vol 97 (1) ◽  
pp. 39-45
Author(s):  
Zhigang Wang ◽  
Ji Li ◽  
Bo Li
Keyword(s):  
Monitoring Network ◽  
Seismic Source ◽  
Microseismic Monitoring ◽  
Source Location ◽  
P Wave ◽  
Monitoring Networks ◽  
Distributed Monitoring ◽  
S Wave ◽  
Location Accuracy ◽  
Seismic Source Location

Seismic source location is the most fundamental and most important problem in microseismic monitoring. However, only P wave has been mostly applied in the existing microseismic monitoring networks, with low location accuracy and poor stability of location result for the microseismic events occurring beyond monitoring networks. The seismic source location was implemented using P wave and S wave in this study to expand the effective monitoring area of a microseismic monitoring network and improve its location accuracy for microseismic events nearby the monitoring network. Then, the seismic source location mechanism using P-S wave was revealed through theoretical derivation and analysis. Subsequently, the program development and numerical simulation were combined to analyze and compare systematically the location effects of differently distributed monitoring networks, those consisting of different quantities of sensors, and those with S wave contained in some sensors under two circumstances: combination of P wave and S wave and single use of P wave. Results demonstrate that adding S wave in the plane enhances the accuracy control in the radius direction of the monitoring network. After S wave is included, the location accuracy within a certain area beyond the monitoring network is improved considerably, the effective monitoring area of the whole network is expanded, and the unstable location zones using only P wave are eliminated. The location results of differently distributed monitoring networks and the influence laws of the quantity of sensors constituting the networks on the location results are acquired. This study provides evidence for microseismic monitoring to realize accurate and stable location within a larger range. Keywords: seismic source location, P wave and S wave, mechanism, location effect

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