Abstract
The Groningen gas field in the Netherlands is an ideal test bed for in-situ reservoir monitoring techniques because of the availability of both active and passive in-reservoir seismic data. In this study, we use deconvolution interferometry to estimate the reflection and transmission response using active and passive borehole data within the reservoir at ∼3-km depth and separate up- and downgoing P- and S-wave fields by f-k filtering. We validate the results using synthetic data of a 1D elastic model built from sonic logs recorded in the well. The estimated full-waveform reflection response for a virtual source at the top geophone is consistent with the synthetic response. For the virtual source at the bottom geophone, the reflection response appears to be phase delayed, though its arrivals are consistent with the local subsurface geology. Similarly, the first-order estimated local transmission response successfully approximates that of the P-wave velocity in the reservoir. The study shows that reliable subsurface information can be obtained from borehole interferometry without detailed knowledge of the medium parameters. In addition, the method could be used for passive reservoir monitoring to detect velocity, attenuation, and/or interface time-lapse variations.
Highlights
The main objective is to show that deconvolution interferometry using check shot and noise borehole data can estimate: (a) The transmission response which corresponds to the velocity structure in the reservoir, and (b) the physical reflection response within and around the reservoir
Our interferometry application to estimate the in-reservoir reflection and transmission response requires up- and downgoing P- and S-wave separation as the input
Using active and passive deep borehole data, we estimate the full-waveform reflection responses by deconvolution interferometry for a virtual source at the top geophone which is consistent with the actual responses from the synthetic data as if we have an active source at the top geophone
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. We use deconvolution interferometry to estimate the transmission and reflection response using SDM-1 borehole data, with a virtual source at the top or bottom geophone. This can be achieved by up- and downgoing wavefield separation in the f -k domain prior to deconvolution [11]. The main objective is to show that deconvolution interferometry using check shot and noise borehole data can estimate: (a) The transmission response which corresponds to the velocity structure in the reservoir, and (b) the physical reflection response within and around the reservoir. We validate the process by applying it first to the synthetic data from the 1D elastic model from well log data provided by the NAM (Nederlandse Aardolie Maatschappij)
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