2D Reflection Seismic Processing and Structural Interpretation for Potential CO2 Storage at Rødby, Denmark

The Danish subsurface is a potential site for CO2 (carbon dioxide) storage due to its geological characteristics and proximity. For CCS (Carbon Capture and Storage) to work effectively, it is crucial to ensure that the reservoir top layer is intact and there is no leakage of CO2 from the injection site, making the top of the reservoir seal a critical factor when evaluating potential CCS sites. This thesis examines the geological and geophysical features of the Rødby area in Denmark, focusing on the potential of the Bunter Sandstone Formation as a CO2 storage reservoir. 2D seismic reflection processing was employed to enhance the signal-to-noise ratio and achieve high-resolution imaging of subsurface structures along the focus line of this thesis profile 4 (P4). The main processing includes bandpass frequency filtering, deconvolution, static corrections, noise attenuation, NMO corrections, and migration, which improved the continuity of the reflections and provided high-resolution images facilitating the detailed geological interpretations. The analysis of the structure revealed that the domal-shaped Rødby structures extending from the Zechstein Formation to the Gassum Formation (below to top) developed through separate phases of salt pillow growth, which resulted in the overlying domed anticline observed today. The interpretation exhibits that the primary reservoir, Bunter Sandstone Formation, has a consistent thickness without any faults, as well as the primary seal (Ørslev Formation) and secondary seal (Falster Formation) in P4, indicating its potential as a reliable CO2 storage reservoir. However, the study encountered challenges due to the crooked line acquisition geometry, which caused irregular midpoint dispersion and distorted reflections, impacting both shallow and deeper subsurface layers. Despite applying various processing filters and migration, discontinuities caused by crooked line surveys couldn’t be improved. This issue was evident in the discontinuities observed in the seismic data affecting the resolution and interpretation of the subsurface structures. This proved the necessity of alternative processing or 3D seismic survey in the future to improve the data quality. This research not only contributed to the detailed understanding of the existing knowledge of subsurface structures in the Rødby area but also offers insights into the effectiveness of seismic processing techniques.