Locating Microseismic Events using Migration-based Deconvolution

Abstract

We present a new approach to generating 3D location maps for microseismic events from 3-component data. The method combines full-waveform vector migration with an imaging condition based on semblance-weighted deconvolution. The semblance-weighted deconvolution keys in on the signal-to-noise conditions of the data to give a high-resolution, low-noise estimate of the locations for the microseismic sources. As the method requires no explicit time picking or event association, it is well suited for an either fully-automated or a semi-automated process. Almost as a by-product, the method provides a natural measure of the uncertainty associated with the locations of the individual micro-earthquakes.

Microseismic search engine

“…Because the method involves traveltime picks, and a hydraulic fracturing project may trigger a few hundreds or thousands of microseismic events interfered with significant noise, applying automatic picking may be difficult. There are also many other event location strategies, which fit essentially into the loose category of migration and require substantialprocessing time (Rentsch et al, 2010;Haldorsen et al, 2012). Note all of these methods determine event locations only, additional efforts need to be made if the information of magnitude and focal mechanism of the microseismic events are needed.…”