Seismic Attributes in Borehole Full Waveform Sonic Logging

Integration of surface seismic and borehole sonic data processing and display techniques provides a means for a detailed description of rock properties such as dipping boundaries, fractures, and permeability. The seismic attributes analysis and the color-coded displays which are adapted for investigation of full wave sonic (FWS) responses of formations reveal additional FWS characteristics helpful in describing the formation near the borehole. In this application the seismic attributes have distinct geophysical meanings Which are specifically pertinent to FWS logging and are called Instantaneous Waveform Characteristics, or IWC. The color-coded displays are called colorgrams. The IWC displayed in the colorgrams are also quantified, plotted as log curves, and interrelated to give useful geophysical parameters such as the quality factor (Q) of the formation. The application of the IWC analytical method is demonstrated with colorgrams from four different wells. All these examples illustrate how the IWC method, enhanced with colorgrams, broadens our analytical understanding of FWS well log data and assists in geological interpretation. It provides valuable information useful for the integration of borehole sonic and seismic data as well as for the development of cross-borehole tomography.