Seismic scattering attributes to estimate reservoir fracture density : a numerical modeling study
Name
55873860-MIT.pdf
Description
Full printable version
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2.79 MB
Format
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Checksum (MD5)
41cf9b17268ece143e268a5804a313d0
Author(s)
Pearce, Frederick D. (Frederick Douglas), 1978-
Advisor(s)
Daniel R. Burns.
Date Issued
2003
Publisher
Massachusetts Institute of Technology
Abstract
We use a 3-D finite difference numerical model to generate synthetic seismograms from a simple fractured reservoir containing evenly-spaced, discrete, vertical fracture zones. The fracture zones are represented using a single column of anisotropic grid points. In our experiments, we vary the spacing of the fracture zones from 10-meters to 100-meters, corresponding to fracture density values from 0.1- to 0.01-fractures/meter, respectively. The vertical component of velocity is analyzed using integrated amplitude and spectral attributes that focus on time windows around the base reservoir reflection and the scattered wave coda after the base reservoir reflection. Results from a common shot gather show that when the fracture zones are spaced greater than about a quarter wavelength of a P-wave in the reservoir we see 1) significant loss of amplitude and coherence in the base reservoir reflection and 2) a large increase in bulk scattered energy. Wavenumber spectra for integrated amplitude versus offset from the time window containing the base reservoir reflection show spectral peaks corresponding to the fracture density. Frequency versus wavenumber plots for receivers normal to the fractures separate backscattered events that correspond to spectral peaks with positive wavenumbers and relatively narrow frequency ranges. In general, backscattered events show an increase in peak frequency as fracture density is increased.
Description
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2003.
Includes bibliographical references (leaves 26-27).
Subjects
Earth, Atmospheric, and Planetary Sciences.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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