Spatial Orientations of Hydraulically Conductive Shear Natural Fractures
for an Arbitrary Stress State: an Analytical Study
Abstract
The paper focuses on spatial orientations of hydraulically conductive
shear fractures existing in naturally fractured fluid saturated rocks.
Hydraulic conductivity of such fractures is considered from the current
stress state of these rocks. The concept of critically stressed
fractures is generally used to establish such relationship. The paper
presents an analytical solution to the problem of obtaining all possible
spatial orientations of critically stressed fractures for an arbitrary
stress tensor. The proposed solution is explicit, providing an
opportunity to predict the spatial orientations of hydraulically
conductive fractures based on results of any sort of solutions to
geomechanical problems considering naturally fractured rocks. The
obtained results may be directly used for planning the development of
oil fields, characterized by considerable contribution of fractures to
permeability in cases when geomechanical modeling takes place. Several
examples of applying the obtained solution in practice are presented in
the paper: critically stressed fractures spatial orientations are
considered for cases of gradual changes in stress tensor components
under specific conditions providing an understanding of the main
tendencies in these spatial orientations.