Optimizing detection of microseismic events by receiver selection on surface monitoring

Microseismic monitoring aims at detecting as weak events as possible by maximizing the signal-to-noise ratio (SNR) of the detection parameters. Whilst the signal depends on a priori unknown source radiation and propagation effects, the noise levels on the receivers can be measured (prior to an event onset) and we show that receivers with a noise above a certain level do not contribute to improving the SNR of the stack. We derive criterion to evaluate the possible contribution of an individual receiver for improving the SNR of the stack function. The effect of the radiation pattern of the microseismic source and propagation path effects on the signal can be included. We demonstrate on a real dataset that the source radiation pattern can be neglected by application of the simplified criterion to the surface monitoring network of vertical component receivers.