Daniel Sopher

Feasibility of utilizing wavelet phase to map the CO2 plume at the Ketzin pilot site, Germany

ABSTRACT Spectral decomposition is a powerful tool that can provide geological details dependent upon discrete frequencies. Complex spectral decomposition using inversion strategies differs from conventional spectral decomposition methods in that it produces not only frequency information but also wavelet phase information. This method was applied to a time‐lapse three‐dimensional seismic dataset in order to test the feasibility of using wavelet phase changes to detect and map injected carbon dioxide within the reservoir at the Ketzin carbon dioxide storage site, Germany. Simplified zero‐offset forward modelling was used to help verify the effectiveness of this technique and to better understand the wavelet phase response from the highly heterogeneous storage reservoir and carbon dioxide plume. Ambient noise and signal‐to‐noise ratios were calculated from the raw data to determine the extracted wavelet phase. Strong noise caused by rainfall and the assumed spatial distribution of sandstone channels in the reservoir could be correlated with phase anomalies. Qualitative and quantitative results indicate that the wavelet phase extracted by the complex spectral decomposition technique has great potential as a practical and feasible tool for carbon dioxide detection at the Ketzin pilot site.

The First Post-injection Seismic Monitor Survey at the Ketzin Pilot CO2 Storage Site: Results from Time-lapse Analysis

The injection of CO2 at the Ketzin pilot CO2 storage site started in June 2008 and ended in August 2013. During the 62 months of injection, a total amount of about 67 kt of CO2 was injected into a ...

Reconstruction of the near-offset gap in marine seismic data using seismic interferometric interpolation

In conventional seismic exploration, especially in marine seismic exploration, shot gathers with missing near-offset traces are common. Interferometric interpolation methods are one of a range of different methods that have been developed to solve this problem. Interferometric interpolation methods differ from conventional interpolation methods as they utilize information from multiples in the interpolation process. In this study we apply both conventional interferometric interpolation (shot domain) and multi-domain interferometric interpolation (shot and receiver domain) to a synthetic and a real towed marine dataset from the Baltic Sea with the primary aim of improving the image of the seabed by extrapolation of near-offset gap. We utilize a matching filter after interferometric interpolation to partially mitigate artefacts and coherent noise associated with the far-field approximation and a limited recording aperture size. The results show that an improved image of the seabed is obtained after performing interferometric interpolation. In most cases the results from multi-domain interferometric interpolation are similar to those from conventional interferometric interpolation. However, when the source-receiver aperture is limited, the multi-domain method performs better. A quantitative analysis for assessing the performance of interferometric interpolation shows that multi-domain interferometric interpolation typically performs better than conventional interferometric interpolation. We also benchmark the interpolated results generated by interferometric interpolation against those obtained using sparse recovery interpolation. This article is protected by copyright. All rights reserved

High-resolution seismic imaging of Paleozoic rocks in the Mora area, Siljan Ring structure, central Sweden

Abstract The Late Devonian Siljan Ring structure in Sweden is the largest known impact structure in Europe. The present-day structure comprises a central dome that is about 20–30 km in diameter, which is surrounded by a ring-shaped depression. In this study, we focus on the southwestern part of the Siljan Ring with the aim to map the structure of the Paleozoic sedimentary rocks. Four 2D high-resolution seismic lines with a total length of about 3 km were acquired in the Mora area. A three component eighty-unit land streamer, combined with wireless recorders, was used for data acquisition along with a weight drop source. Processing of the data shows that clear reflections are present, but results are less distinct where external noise was present during acquisition or the maximum source-receiver offset was too short. Petrophysical measurements on core samples, core log data and a density model along one line were used to guide the interpretation of the seismic sections. These data demonstrate that fault blocks are present in the study area and that the individual blocks have been affected differently by impact-related tectonics.

Feasibility Study of Seismic Interferometry for CO2 Storage Monitoring - An Example from the Ketzin Site

Seismic interferometry is a relatively low cost method compared with conventional seismic monitoring methods and can be performed together with microseismic and reservoir monitoring. These features make it a new potential tool for carbon dioxide storage monitoring. In this study, we acquired 6 nights of ambient noise data were recorded at the Ketzin experimental CO2 injection Site located in Ketzin, west of Berlin, Germany, in August 2013. An active survey was also acquired at the same time along of one line for a source test. Passive seismic interferometry was applied to the recorded noise data to reconstruct common shot gathers. The virtual shot gathers was processed to obtain a stacked section. The results show that the passive stacked sections are less coherent and low resolution compared with the active stacked section. However, we could also find some similar features to both the passive and active stacked sections in the shallow parts and even some agreement in the deeper parts.