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The effect of microstructure and nonlinear stress on anisotropic seismic velocities

Verdon, James P.; Angus, Doug A.; Kendall, J. Michael and Hall, Stephen LU (2008) In Geophysics 73(4). p.41-51
Abstract
Recent work in hydrocarbon reservoir monitoring has focused on developing coupled geomechanical/fluid-flow simulations to allow production-related geomechanical effects, such as compaction and subsidence, to be included in reservoir models. To predict realistic time-lapse seismic signatures, generation of appropriate elastic models from geomechanical output is required. These elastic models should include not only the fluid saturation effects of intrinsic, shape-induced, and stress-induced anisotropy, but also should incorporate nonlinear stress-dependent elasticity. To model nonlinear elasticity, we use a microstructural effective-medium approach in which elasticity is considered as a function of mineral stiffness and additional... (More)
Recent work in hydrocarbon reservoir monitoring has focused on developing coupled geomechanical/fluid-flow simulations to allow production-related geomechanical effects, such as compaction and subsidence, to be included in reservoir models. To predict realistic time-lapse seismic signatures, generation of appropriate elastic models from geomechanical output is required. These elastic models should include not only the fluid saturation effects of intrinsic, shape-induced, and stress-induced anisotropy, but also should incorporate nonlinear stress-dependent elasticity. To model nonlinear elasticity, we use a microstructural effective-medium approach in which elasticity is considered as a function of mineral stiffness and additional compliance is caused by the presence of low-aspect ratio displacement discontinuities. By jointly inverting observed ultrasonic P- and S-wave velocities to determine the distribution of such discontinuities, we assessed the appropriateness of modeling them as simple, planar, penny-shaped features. By using this approximation, we developed a simple analytical approach to predict how seismic velocities will vary with stress. We tested our approach by analyzing the elasticity of various sandstone samples; from a United Kingdom continental shelf (UKCS) reservoir, some of which display significant anisotropy, as well as two data sets taken from the literature. (Less)
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author
publishing date
type
Contribution to journal
publication status
published
subject
in
Geophysics
volume
73
issue
4
pages
41 - 51
publisher
Soc Exploration Geophysicists
external identifiers
  • Scopus:48949100927
ISSN
0016-8033
DOI
10.1190/1.2931680
language
English
LU publication?
no
id
85566d7c-51b4-497c-b097-fdea922146a1 (old id 2441193)
date added to LUP
2012-04-27 14:23:05
date last changed
2016-11-27 04:38:36
@misc{85566d7c-51b4-497c-b097-fdea922146a1,
  abstract     = {Recent work in hydrocarbon reservoir monitoring has focused on developing coupled geomechanical/fluid-flow simulations to allow production-related geomechanical effects, such as compaction and subsidence, to be included in reservoir models. To predict realistic time-lapse seismic signatures, generation of appropriate elastic models from geomechanical output is required. These elastic models should include not only the fluid saturation effects of intrinsic, shape-induced, and stress-induced anisotropy, but also should incorporate nonlinear stress-dependent elasticity. To model nonlinear elasticity, we use a microstructural effective-medium approach in which elasticity is considered as a function of mineral stiffness and additional compliance is caused by the presence of low-aspect ratio displacement discontinuities. By jointly inverting observed ultrasonic P- and S-wave velocities to determine the distribution of such discontinuities, we assessed the appropriateness of modeling them as simple, planar, penny-shaped features. By using this approximation, we developed a simple analytical approach to predict how seismic velocities will vary with stress. We tested our approach by analyzing the elasticity of various sandstone samples; from a United Kingdom continental shelf (UKCS) reservoir, some of which display significant anisotropy, as well as two data sets taken from the literature.},
  author       = {Verdon, James P. and Angus, Doug A. and Kendall, J. Michael and Hall, Stephen},
  issn         = {0016-8033},
  language     = {eng},
  number       = {4},
  pages        = {41--51},
  publisher    = {ARRAY(0x9365928)},
  series       = {Geophysics},
  title        = {The effect of microstructure and nonlinear stress on anisotropic seismic velocities},
  url          = {http://dx.doi.org/10.1190/1.2931680},
  volume       = {73},
  year         = {2008},
}