Construction of Synthetic Seismograms

Abstract

Synthetic seismograms are seismic traces calculated from well log data. They provide a link between actual seismic records and borehole logs. Complete sonic and density logs are needed for the generation of synthetics. Velocity and density readings from the logs are used to calculate the acoustic impedence of the subsurface layers. Then, an impulse response of these layers is calculated using reflection and transmission coefficients. Finally, the synthetic is generated by convolving the impulse response with a Ricker Wavelet. Synthetic seismograms are very useful in determining the wave characteristics associated with changes in stratigraphy. They can be used to define such things as unconformities, and even large scale facies changes. Synthetic seismograms can only be calculated as approximations. However, they are still valuable tools for enhancing seismic interpretation.