Inversion and Application of Seismic Q Factor - Field Dataset Examples.
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Date
2014
Journal Title
Journal ISSN
Volume Title
Publisher
Akamai University Hawaii, USA
Abstract
In the two previous papers, we introduced a new method for measuring attenuation in reflection seismic data (Raji and Rietbrock, 2013), and a new algorithm for Q-compensation process, to correct the undesirable effects of attenuation in seismograms (Raji and Rietbrock, 2012). We tested the methods with synthetic data examples, and where possible, compared our results with those achieved by other published methods. In this paper, we demonstrate the appropriateness of the Q measuring algorithm and the Q compensation scheme to field dataset, using a set of 3D data recorded in the Gullfaks field, Norway.
The robust features of the Q measuring algorithm include the use of spectral shape factor and variable window length. The shape factor allows the user to represent the real seismic wavelet with several shapes without altering the mathematical formula, while variable window length reduced interference during spectral computation. The average interval 1/Q calculated from 500 measurements at each of the four time-depth intervals are 0.0196, 0.0573, 0.0389, and 0.0220, for intervals AB, BC, CD, and DE, respectively. Variation in the attenuation structure of the survey area is described with 2D attenuation profiles. Attenuation compensation in field seismograms is also attempted. inverse filters are designed for the various earth layers approximated from the seismic traces, using the interval average 1/Q . The inverse filtering scheme is applied to the traces one after the other using Matlab programs specifically designed for the study. The compensated data shows higher quality in terms of amplitude size, frequency content and image resolution,
Description
Keywords
Seismic Q factor, Interval Q measurement, Attenuation compsensation, Reflection seismic records
Citation
Raji, W. O., P. I. Olasehinde, H. O. Abubakar, R. A. Alabi, (2014): Inversion and Application of Seismic Q Factor - Field Dataset Examples. Pacific Journal of Science and Technology, Vol. 15(1) 318-327.