Computer correlation of well-log data usually presumes some prior knowledge of the direction and degree of stratigraphic thickening. Model studies, however, show that power spectra can identify the relative changes in stratigraphic intervals between wells. Given the stretch factor, the displacement between logs is computed without relying on iterative procedures. Study of real data shows that each well log is associated with a specific set of frequencies complicated by the presence of noise. Therefore, successful applications depend on the process of modifying the frequency spectra before correlation.

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