Detection and analysis of microseismic events using a Matched Filtering Algorithm (MFA)
- Author(s)
- Enrico Caffagni, David W. Eaton, Joshua P. Jones, Mirko van der Baan
- Abstract
A new Matched Filtering Algorithm (MFA) is proposed for detecting and analysing microseismic events recorded by downhole monitoring of hydraulic fracturing. This method requires a set ofwell-located template ('parent') events,which are obtained using conventional microseismic processing and selected on the basis of high signal-to-noise (S/N) ratio and representative spatial distribution of the recorded microseismicity. Detection and extraction of 'child' events are based on stacked, multichannel cross-correlation of the continuous waveform data, using the parent events as reference signals. The location of a child event relative to its parent is determined using an automated process, by rotation of the multicomponent waveforms into the ray-centred co-ordinates of the parent and maximizing the energy of the stacked amplitude envelope within a search volume around the parent's hypocentre. After correction for geometrical spreading and attenuation, the relative magnitude of the child event is obtained automatically using the ratio of stacked envelope peak with respect to its parent. Since only a small number of parent events require interactive analysis such as picking P- and S-wave arrivals, the MFA approach offers the potential for significant reduction in effort for downhole microseismic processing. Our algorithm also facilitates the analysis of single-phase child events, that is, microseismic events for which only one of the S- or P-wave arrivals is evident due to unfavourable S/N conditions. A real-data example using microseismic monitoring data from four stages of an open-hole slickwater hydraulic fracture treatment in western Canada demonstrates that a sparse set of parents (in this case, 4.6 per cent of the originally located events) yields a significant (more than fourfold increase) in the number of located events compared with the original catalogue. Moreover, analysis of the new MFA catalogue suggests that this approach leads to more robust interpretation of the induced microseismicity and novel insights into dynamic rupture processes based on the average temporal (foreshock-aftershock) relationship of child events to parents.
- Organisation(s)
- Department of Meteorology and Geophysics
- External organisation(s)
- University of Alberta, University of Calgary
- Journal
- Geophysical Journal International
- Volume
- 206
- Pages
- 644-658
- No. of pages
- 15
- ISSN
- 0956-540X
- DOI
- https://doi.org/10.1093/gji/ggw168
- Publication date
- 07-2016
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 105126 Applied geophysics, 105122 Seismic, 105124 Tectonics, 105102 General geophysics
- Keywords
- ASJC Scopus subject areas
- Geochemistry and Petrology, Geophysics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/8819522d-d684-4b36-871b-414f5634d886