Reservoir characterization using seismic data after frequency bandwidth enhancement

摘要

Reservoir characterization is a crucial prerequisite to predict the economic potential of a hydrocarbon reservoir or to examine different production scenarios. Unfortunately, it is impossible to determine the exact reservoir properties at the required scale. The most abundant seismic data have a resolution of around 30 m. Wells resolve the reservoir down to the centimetre scale, but only at some points in the vertical direction. This paper presents a method, referred to as frequency bandwidth enhancement (FBE), for enhancing the frequency bandwidth and restoring high frequencies. The method increases the resolution of seismic data by padding the frequency spectrum of seismic wavelets, thus pushing the notch corresponding to the time limit of resolution to a higher part of the spectrum. This approach ( patent pending) results in sharper wavelets capable of identifying thinner beds. A by-product of extending the frequency spectrum is the elimination of the tuning effect of beds thinner than the new limit of resolution. When tuning curves before and after the process are compared, it is observed that although different, the differences are minuscule and insignificant compared to the benefits coming from being able to resolve thinner beds. The procedure enunciated here is robust and helps define trends better, leading to more confident interpretations. Such applications could redefine prospects, which in some cases may have been declared unsuccessful on the basis of interpretation of seismic data with the original bandwidth. The reservoir characterization is realized with the aid of coherence cube processing, which is an extremely powerful tool to efficiently exploit the wealth of structural and stratigraphic information encapsulated in the seismic waveforms of 3D seismic data volumes.