Seismic interpretation pitfalls caused by interference effects, exemplified by seismic modeling of outcropping chalk successions

Abstract

Interference and inherent resolution limitations are well-recognized problems in reflection seismic data and have over time led to misinterpretations. Acquisition of seismic data containing a broad range of frequencies, including high frequencies, does not solve this problem but merely moves the problem to a finer scale. Forward seismic modeling of known geologic scenarios is a valuable tool for studying anticipated seismic responses of successions with a given set of geologic and/or rock physical characteristics and for predicting interpretational challenges. We perform finite-difference-based seismic forward modeling on a conceptual geologic model derived from outcropping chalk sections in southeast Denmark and evaluate possible pitfalls that may hamper interpretation of seismic data acquired from strata with similar characteristics. We demonstrate that interbedded strata with contrasting physical properties and variable thickness can result in interference effects resembling faults and fractures. The result has significance for characterization, e.g., geothermal sites, potential CO2 storage targets, groundwater reservoirs, and hydrocarbon exploration sites, in which the proper imaging of faults and fractures from seismic data is an essential task.