Uncertainties in full waveform moment tensor inversion due to limited microseismic monitoring array geometry

2011 ◽  
Author(s):  
Ahyi Kim
Keyword(s):  
Moment Tensor ◽  
Microseismic Monitoring ◽  
Moment Tensor Inversion ◽  
Full Waveform ◽  
Array Geometry

scholarly journals Adaptive moment-tensor joint inversion of clustered microseismic events for monitoring geological carbon storage

2019 ◽  
Vol 219 (1) ◽  
pp. 80-93
Author(s):  
Yu Chen ◽  
Lianjie Huang
Keyword(s):  
Carbon Storage ◽  
Oil Recovery ◽  
Joint Inversion ◽  
Moment Tensor ◽  
Crack Opening ◽  
Cost Effective ◽  
Microseismic Monitoring ◽  
Moment Tensor Inversion ◽  
Inversion Method ◽  
Microseismic Events

SUMMARY Moment-tensor inversion of induced microseismic events can provide valuable information for tracking CO2 plumes at geological carbon storage sites, and study the physical mechanism of induced microseismicity. Accurate moment-tensor inversion requires a wide-azimuthal coverage of geophones. Cost-effective microseismic monitoring for geological carbon storage often uses only one geophone array within a borehole, leading to a large uncertainty in moment-tensor inversion. We develop a new adaptive moment-tensor joint inversion method to reduce the inversion uncertainty, when using limited but typical geophone receiver geometries. We first jointly invert a number of clustered microseismic events using a uniform focal mechanism to minimize the waveform misfit between observed and predicted P and S waveforms. We then invert the moment tensor for each event within a limited searching range around the joint inversion result. We apply our adaptive joint inversion method to microseismic data acquired using a single borehole geophone array at the CO2-Enhanced Oil Recovery field at Aneth, Utah. We demonstrate that our inversion method is capable of reducing the inversion uncertainty caused by the limited azimuthal coverage of geophones. Our inverted strikes of focal mechanisms of microseismic events are consistent with the event spatial distribution in subparallel pre-existing fractures or geological imperfections. The large values up to 40 per cent of the CLVD components might indicate crack opening induced by CO2/wastewater injection or rupture complexity.

Adaptive full-waveform moment-tensor inversion of microseismic data

2021 ◽  
Author(s):  
Kai Gao ◽  
Lianjie Huang ◽  
Yan Qin ◽  
Ting Chen ◽  
David Coblentz ◽  
...  
Keyword(s):  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Full Waveform ◽  
Microseismic Data

Application of full-waveform event location and moment-tensor inversion for Groningen induced seismicity

2018 ◽  
Vol 37 (2) ◽  
pp. 92-99 ◽  
Author(s):  
Chris Willacy ◽  
Ewoud van Dedem ◽  
Sara Minisini ◽  
Junlun Li ◽  
Jan Willem Blokland ◽  
...  
Keyword(s):  
Induced Seismicity ◽  
Moment Tensor ◽  
Moment Tensor Inversion ◽  
Full Waveform ◽  
Event Location

Microseismic design studies

Geophysics ◽  
2011 ◽  
Vol 76 (6) ◽  
pp. WC17-WC25 ◽  
Author(s):  
Ulrich Zimmer
Keyword(s):  
Data Acquisition ◽  
Moment Tensor ◽  
Velocity Model ◽  
Microseismic Monitoring ◽  
Moment Tensor Inversion ◽  
Distributed Temperature Sensing ◽  
Design Studies ◽  
Location Accuracy ◽  
Tight Reservoir ◽  
Event Location

Microseismic monitoring has become an important part of borehole completions in tight-reservoir formations. Usually, clear objectives for a microseismic survey are set prior to the data acquisition. The possibility of meeting these objectives is determined by the acquisition geometry, the target formation, the completion schedule, and only to a lesser extent, by the data quality itself. Provided is a tutorial on the content and use of prejob modeling and design studies as a tool to anticipate viewing distances, data quantity, location accuracy, event magnitudes, achievable mapping distances, expected waveforms, and noise levels. In addition, potential challenges in meeting the survey objectives can be identified and solutions to these challenges can be devised prior to the survey. For downhole surveys, this involves the evaluation of different sensor array geometries and their impact on the location accuracy in different parts of the expected model. The sensitivity of the event location on the velocity model can be estimated using an initial log-based model. Recently, the detailed characterization of the event mechanism in form of a moment tensor inversion has received increased attention. The accuracy of the inverted moment tensor depends largely on the coverage of the focal sphere, i.e., the distribution of the sensors around the event location. Based on the sensor positions, areas with high- and low-quality moment tensor inversion results can be identified prior to data acquisition through the distribution of the condition number. Depending on the survey objectives and the given constraints, the microseismic design study might show that the survey objectives cannot be met. In this case, it is possible to evaluate alternate technologies, e.g., distributed temperature sensing (DTS), ahead of the project for their potential to meet these challenges.

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