Stress–Strain Behavior in Heavy Oil Reservoirs Using Mohr–Coulomb Constitutive Model: Fid-Bau Portal

Stress–Strain Behavior in Heavy Oil Reservoirs Using Mohr–Coulomb Constitutive Model

Morales-Monsalve, C. B. / Alzate-Espinosa, G. A. / Arbelaez-Londoño, A.

Abstract Heavy oil reservoirs are subjected to changes in temperature during thermal recovery processes. Increases in temperature and effective stress occurring during these operations can generate changes in the mechanical behavior of the reservoir and the surrounding formations. Colombia has a huge amount of heavy oil reserves; nevertheless, the behavior of typical Colombian unconsolidated sandstones under thermal recovery conditions has not been completed studied. In order to understand the behavior of this type of reservoirs during thermal recovery processes, the stress–strain behavior of these sands is analyzed using Mohr–Coulomb constitutive model. The stress–strain behavior of Colombian unconsolidated sandstones is represented using Mohr–Coulomb constitutive mode with two modifications in order to capture the behavior of this material. The first modification is based on the expansion/contraction of the yielding surface, which is based on the changes of the internal friction angle and the cohesion through plastic strain, i.e., mobilized strength properties. The second change is based on the inclusion of a non-associative flow rule, which allows representing dilatant/contractive behavior under dilation angle concept. These modifications are done in order to represent hardening-strain and softening-strain behavior and to capture the volumetric changes on unconsolidated sandstones.