Suppressing spurious events in the image from microseismic data using Poynting vector

Abstract

In this study, we imaged pre-existing fractures adjacent to the hydraulic fracturing zone using seismic signals acquired from microseismic events with Elastic Reverse Time Migration with Source Independent Converted Phase (ERTM SICP) imaging condition. This method can not only save the computational costs but also carry out the migration without the information on the locations of microseismic events.

However, the results showed linear spurious events which are caused by velocity difference between P- and S- waves. To overcome this problem, we suggested the modified ERTM SICP imaging condition using Poynting vector which can calculate the direction of wave propagation. We used the idea that the angle between the propagating directions of P- and S- wavefield has different aspects where wavefields are mode-converted and linear spurious events are produced. We clearly showed that our modified imaging condition can successfully suppress the linear spurious events through numerical experiments.