The thickness of many reservoirs is only a fraction of the vertical dimension spanned by the dominant wavelength of the seismic wavelet that illuminates and images those reservoirs. Such reservoirs are referred to as seismic thin beds.

The seismic reflection process that occurs when two or more interfaces are separated vertically by less than one-fourth of a wavelength (thin beds) differs from the reflection process associated with isolated interfaces (thick beds). The purpose of this module is to demonstrate how seismic reflection amplitude can be used to interpret reservoirs that have thicknesses less than one-fourth of the dominant wavelength of the illuminating wavefield.

To gain this understanding, you will examine the effects of changing the frequency content of the illuminating seismic wavelet and will image a simple wedge model with low-frequency and high-frequency wavelets. By performing this exercise you will learn what determines whether a thin bed is resolved or detected by the illuminating wavefield. You will also consider the question "What effect do shale stringers within a thin bed have on the thin-bed reflection response?" This analysis is of special value in developing rules to follow when estimating net pay in heterogeneous thin beds.