Schoenberg's angle on fractures and anisotropy: A study in orthotropy |

For vertical-fracture sets at arbitrary orientation angles to each other
- but not perfectly randomly oriented, I present a detailed model
in which the resulting anisotropic fractured medium generally has
orthorhombic symmetry overall. Analysis methods of Schoenberg are emphasized,
together with their connections to other similarly motivated and conceptually
related methods by Sayers and Kachanov, among others. Examples show how
parallel vertical fracture sets having HTI symmetry turn into orthotropic
fractured media if some subsets of the vertical fractures are misaligned
with the others, and then the fractured system can have VTI symmetry
if all the fractures are aligned either randomly, or half parallel and
half perpendicular to a given vertical plane. Another orthotropic case
of vertical fractures in an otherwise VTI earth system treated previously
by Schoenberg and Helbig is compared to, and contrasted with, other
examples treated here.

- INTRODUCTION
- FRACTURE ANALYSIS
- VANISHING OF THE ANELLIPTICITY PARAMETERS
- VERTICAL FRACTURES IN VTI EARTH
- DISCUSSION OF VARIOUS FRACTURE MODELS
- CONCLUSIONS
- ACKNOWLEDGMENTS
- Bibliography
- About this document ...

Schoenberg's angle on fractures and anisotropy: A study in orthotropy |

2009-10-19