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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 980

Last Page: 980

Title: How to Correct Seismic Data to Improve Seismic Impedance Logs: ABSTRACT

Author(s): E. Robein, J. M. Komatitsch

Article Type: Meeting abstract


Besides geometrical and velocity effects, two global parameters may disturb the comparison between acoustic logs recorded in a borehole and those derived from seismic data: (a) the amplitude spectrum of the basic seismic wavelet, which controls the power of resolution; and (b) its phase characteristics that monitor the resemblance. The latter is of major importance in stratigraphic interpretation of seismic impedance logs (recognition of geologic transitions). The most important causes of distortions can sometimes be determined and compensated. The seismic source signature needs to be recorded, analyzed, and processed to determine the seismic wavelet. Phase distortions due to recording equipment (geophones and laboratory) are very important, and need to be corrected. Trav l into the earth introduces multiples and absorption. Multiples can be dealt with in the classic way with a few precautions. Then an estimation of the amplitude spectrum of signal and noise at a given time-depth provides one with a quantitative estimate of the best achievable resolution of the actual data, and the absorption curve in amplitude spectrum using the recorded source spectrum. A good match between experiments and theory leads to the estimated impulse response of absorption at a given time, and reversely, to an optimized (eventually time-varying) correction operator.

Further conventional deconvolution processes should not be used. Nevertheless, when distortions cannot be corrected, and if well data are available, a deconvolution program controlling both amplitude and phase can be used interactively to achieve an equivalent result.

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Copyright 1997 American Association of Petroleum Geologists