Enhanced Detection and Location of Microseismic Events Using a Novel Matched Filtering Method

A new Matched Filtering Algorithm is proposed for detecting microseismic events recorded by downhole monitoring of hydraulic fracturing. This method requires a set of well-located template (‘parent’) events, and representative spatial distribution of the recorded microseismicity. Detection and extraction of ‘child’ events are based on stacked, multi-channel 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 multi-component waveforms into the ray-centered co-ordinates of the parent and maximizing the energy of the stacked amplitude envelope within a search volume around the parent’s hypocentre. Relative magnitude of the child event is obtained automatically using the ratio of stacked envelope peak with respect to its parent.

A real-data example using microseismic monitoring data from an open-hole slickwater hydraulic fracture treatment in western Canada demonstrates that a sparse set of parents yields a significant (more than fourfold increase) in the number of located events compared with the original catalog

Relative locations obtained using this approach provide more easily interpretable spatio-temporal patterns of the distribution of microseismicity, which can then be incorporated into the assessment of the stimulation program.