SYNTHETIC SEISMOGRAMS FROM SONIC, DENSITY, AND RESISTIVITY FOR THE ILLINOIS BASIN IN WESTERN KENTUCKY

Using well log data to create synthetic seismograms is a common practice in geophysical studies. In most cases a sonic log and a density log are used to create an acoustic impedance log from which a synthetic seismogram is then created. Often a synthetic seismogram is needed, but the available well data does not include a sonic log. A method may be employed for generating reliable and valid synthetic seismograms from the acoustic impedance when only density or resistivity log data is present. In our study area, located in the Illinois Basin in the vicinity of Western Kentucky, we acquired data from several wells that have sonic, density, and resistivity logs. Synthetic seismograms were created in four ways; using the sonic data only (v), using the density data only (ñ), using the resistivity data only, and from the calculated acoustic impedance log. Wavelets of different frequencies were used to generate the synthetic seismograms. Comparisons of the synthetic seismograms were done to see if a viable synthetic trace can be generated when sonic log records are not available. The synthetic seismograms were then correlated to seismic data that has been recently collected in the area. Additional well data is being gathered for this Western Kentucky study area to determine if the synthetic seismograms generated from density log curves, and/or resistivity log curves will be useful in correlations to the seismic data available throughout the area.