4,231
edits
Changes
Jump to navigation
Jump to search
Line 22:
Line 22: − +
Fracture threshold in the real world (view source)
Revision as of 14:37, 30 July 2014
, 14:37, 30 July 2014→Stress and poisson's ratio variation
[[file:evaluating-top-and-fault-seal_fig10-42.png|thumb|300px|{{figure number|1}}Chart of P<sub>f</sub> vs. pore pressure for a range of overburden stress gradients (0.5–1.0).]]
[[file:evaluating-top-and-fault-seal_fig10-42.png|thumb|300px|{{figure number|1}}Chart of P<sub>f</sub> vs. pore pressure for a range of overburden stress gradients (0.5–1.0).]]
==Stress and poisson's ratio variation==
==Stress and Poisson's ratio variation==
Although the variables used to calculate the fracture pressure commonly are generalized as a smooth curve, there are local variations and departures from this generalized curve. The principal horizontal stress, ε<sub>3</sub>* and [http://en.wikipedia.org/wiki/Poisson%27s_ratio%20Poisson's%20ratio Poisson's ratio] depend on lithology and bed geometry as well as depth and compaction.<ref name=ch10r52 />
Although the variables used to calculate the fracture pressure commonly are generalized as a smooth curve, there are local variations and departures from this generalized curve. The principal horizontal stress, ε<sub>3</sub>* and [http://en.wikipedia.org/wiki/Poisson%27s_ratio%20Poisson's%20ratio Poisson's ratio] depend on lithology and bed geometry as well as depth and compaction.<ref name=ch10r52 />