Inverting seismic traces is the means of finding a velocity or acoustic-impedance model from the recorded traces. Data are processed in preserved-amplitude mode. A wavelet inverse filtering results in a series of reflection coefficients. Reflection coefficients are simple functions of velocities and densities. A transformation of the series of reflection coefficients into relative velocities provides a display where the inverted seismic traces at a well location can be directly correlated to the sonic log.

Prediction of lateral changes affecting the formations intersected by the well is the most direct application. Provided the original surface seismic data have a sufficiently broad frequency spectrum, the inversion improves the detection of thin beds and lateral facies changes. Two examples of reservoir studies illustrate the application of the method: the first is in a deltaic sandstone and shale sequence; the second is a shelf-carbonate province.

End_of_Article - Last_Page 513------------