No abstract

A 3D 25-fold seismic survey with a bin size of 12 by [Formula: see text] and about [Formula: see text] of subsurface coverage was acquired in 2005 near a former natural gas storage site west of Berlin, as part of the five-year EU funded [Formula: see text] project. Main objectives of the seismic survey were to verify earlier geologic interpretations of structure based on vintage 2D seismic and borehole data and to map, if possible, the reservoir pathways in which the [Formula: see text] will be injected at [Formula: see text] depth, as well as providing a baseline for future seismic surveys and planning of drilling operations. The uppermost [Formula: see text] are well imaged and show an anticlinal structure with an east-west striking central graben on its top that extendsdown to the target horizon. About [Formula: see text] of throwis seen on the bounding faults. No faults are imaged near the planned drill sites. Remnant gas, cushion and residual gas, is present near the top of the anticline in the depth interval of about [Formula: see text] and has a clear seismic signature; both higher amplitudes in the reservoir horizons and velocity pulldown are observed. Amplitude mapping of these remnant gas horizons shows that they do not extend as far south as the injection site, which is located on the southern flank of the anticline. Amplitude anomalies, gas chimneys along an east-west striking fault, show that the stored or remnant gas either has been or is presently migrating out of the reservoir formations. Summed amplitude mapping of the planned injection horizon indicates that this lithologically heterogeneous formation may be more porous at the injection site.

: Application of the continuous wavelet transform on seismic data for mapping of channel deposits and gas detection at the CO2SINK site, Ketzin, Germany. -Geophysical Prospecting, 57, 1, 111-123 DOI: 10.1111/j.1365-2478.00723.x. AbstractConventional seismic data are band limited and, therefore, provide limited geological information.Every method that can push the limits is desirable for seismic data analysis. Recently, time-frequency decomposition methods are being used to quickly extract geological information from seismic data and, especially, for revealing frequency dependent amplitude anomalies. Higher frequency resolution at lower frequencies and higher temporal resolution at higher frequencies are the objectives for different time-frequency decomposition methods. Continuous Wavelet Transform techniques, which are the same as narrow-band spectral analysis methods, provide frequency spectra with high temporal resolution without the windowing process associated with other techniques. Therefore, this technique can be used for analyzing geological information associated with low and high frequencies that normally cannot be observed in conventional seismic data. In particular, the Continuous Wavelet Transform is being used to detect thin sand bodies and also as a direct hydrocarbon indicator. This paper presents an application of the Continuous Wavelet Transform method for mapping of potential channel deposits, as well as remnant natural gas detection by mapping low frequency anomalies associated with the gas. The study was carried out at the experimental CO 2 storage site at Ketzin, Germany (CO 2 SINK). Given that reservoir heterogeneity and faulting will have significant impact on the movement and storage of the injected CO 2 our results are encouraging for monitoring the migration of CO 2 at the site. Our study confirms the efficiency of the Continuous Wavelet Transform decomposition method for detection of frequency dependent anomalies which may be due to gas migration during and after the injection phase and in this way it can be used for real-time monitoring of the injected CO 2 from both surface and borehole seismics. : Application of the continuous wavelet transform on seismic data formapping of channel deposits and gas detection at the CO2SINK site,