Common-receiver Gathers as a Tool for Analysis of Microseismic Waveforms and Quality of Time Picks

We introduce an approach for analysis of microseismic waveform data. More precisely, we propose a method to assemble recordings into common-receiver gathers sorted in a way that neighboring traces in a gather correspond to events located close to each other. We assume that microseismic sources located at a small distance are expected to produce similar traces recorded at the same receiver. Therefore, apparent inconsistency between neighboring traces can be considered as an indication of some error in data. We present an algorithm for sorting microseismic recordings in the case when events are located and for the situation when only arrival picks are defined.

The algorithm is applied to a cloud of more than a thousand induced microseismic events recorded at two borehole arrays during one stage of hydraulic fracturing. We construct both arrival time based and location based gathers and show examples of wrong arrival time picks in a dataset which can hardly be revealed from the analysis of individual recordings or common-shot gathers. We demonstrate that this approach can be used for detecting secondary arrivals such as reflections. Presented algorithm is relatively simple and can be easily included into the microseismic data processing workflow as a quality control tool.