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Passive Seismic Study at an Oil and Gas Field in Voitsdorf, Austria
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Second EAGE Passive Seismic Workshop - Exploration and Monitoring Applications 2009, Mar 2009, cp-122-00033
- ISBN: 978-90-73781-59-7
Abstract
We present the results of a passive seismic survey over two separate reservoirs of an explored oil and gas field near Voitsdorf, Austria. Four different spectral attributes of the ambient seismic wave field are used to identify spatial correlations between anomalies in the surface wave field and the presence of hydrocarbons in the subsurface. The attributes quantify characteristic features of the wave field’s Fourier spectra in the low-frequency range (< 10Hz). The data indicate the position of the southern reservoir. The northern reservoir is less clearly identified. Nevertheless, using several attributes significantly increases the reliability of hydrocarbon reservoir detection compared to using only one attribute. Time-reverse modeling applied to the same data-set shows that the observed attribute anomalies at the surface may be caused by low-frequency seismic energy that is emitted from the reservoir areas. Preliminary results of a time-lapse experiment (comparison of data acquired in April 2007 and in April 2008, respectively) reveals a good reproducibility for two of the four attributes. A first comparison between time reverse modeling applied to the 2007 and the 2008 data-set consistently indicates the presence of seismic sources in the area of the two reservoirs.