Czy tłumienie fal sejsmicznych może być źródłem informacji o stopniu nasycenia skał zbiornikowych gazem? - studium modelowe

One of the main problems of hydrocarbon prospecting within the Carpathian Foredeep is identification of non-commercial objects that exhibit anomalous image on seismic sections.Within gas saturated layers, apart from acoustic impedance variations, seismic energy attenuation also changes which results in shadow zone under the reservoir. The lack of measurements which show variation of petrophysical parameters (velocity, density, attenuation) in relation to gas saturation as well as coexistent dependence of seismic image on a number of parameters resulted in development of non-commercial gas reservoir identification criteria on the basis of seismic modeling. The purpose of seismic modeling was evaluation of changes in seismic image caused by attenuation that is related to gas saturation degree. Theoretical wavefield was calculated for seismogeological model constructed for TO152005 profile within Łukowa gas reservoir. Wide range of performed modeling, with an assumption that attenuation is a function of gas saturation, emphasize low attenuation impact of fully gas saturated layers and high impact of partially saturated layers which changes both amplitude and frequency of theoretical wavefield within gas reservoirs. Above criterion could be a basis for identification of partially saturated reservoir layers, however, industrial application of the criterion requires more intensive research on dependence of seismic energy attenuation on gas saturation.