Passive Seismic Ambient Noise Correlation: An Example from the Ketzin Experimental CO2 Storage Site, Germany

Abstract

©2014 The Authors.©2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. Passive seismic ambient noise correlation is potentially a new tool to monitor carbon dioxide storage sites. Unlike conventional monitoring tools, such as time-lapse active seismic surveys, the passive seismic ambient noise correlation method is a relatively low cost method and can be performed together with microseismic and reservoir monitoring. In this study, we test the method at the Ketzin CO<inf>2</inf> storage site, Germany. A new passive seismic survey was performed in August 2013 together with an active survey in conjunction with a source test. The survey consisted of tow profiles line 1 and line 2. line 1 contaubed 42 10 Hz geophones spaced at 24 m intervals and Line 2 contained 23 DSU3 (3-component MEMS) sensors spaced at 5 m intervals. In total, 6 nights and 3 daytime series of ambient noise data were recorded. First, we applied autocorrelation to the passive data records to reconstruct the reflection response. results show good structural correlation with a stacked section from the active data. Then we used passive seismic interferometry to reconstruct common shot gathers for each receiver location. Surface waves were observed in some retrieved gathers from Line 1. However, for Line 2 we also observed refracted and reflected waves in some retrieved shot gathers. Here we review ambient noise correlation methods and compare our results with active seismic data.