References
1. Rock mechanics, Heriot –Watt University, 2012.
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Institute of Petroleum Engineering Heriot-Watt Approved Support Centre TPU Msc Reservoir evaluation and Management 2013-2014 |
Poroplasticity essay
Ilya I. Alekhin
The Mohr –
Coulomb criterion is inadequate for many geotechnical models. With
Mohr analysis it cannot possible to answer on next several questions.
Why the
stress component is reduced? What happens after failure of the rock?
How does system behave in general (because the sample is a small part
of the big system)? Do they adjacent material change in stress state?
[1]. So we cannot say nothing about interaction between layers of
rock even if model is simple stacked sequence of rock layers. But
poroplasticity approach considers interaction between system elements
and also represents that stress state of a natural system is the
dependent parameter. It can get opportunity to define the links that
have influence on stress state. In the Mohr – Coulomb criterion it
is assumed that stress components change at random. Also
poroplasticity approach takes in account influence of pressure of the
pore fluids that can destroy the main prediction in Mohr theory.
Since pore pressure increase during for example compaction the yield
can be prevented. Moreover poroplasticity model considers the
behavior of rock after yielding too.