This tutorial example aims to illustrate the geomechanics involved in the simulation of Pore Volume Compressibility tests (PVC) adopting the ParaGeo-IX coupling workflow.

 

PVC tests are uniaxial lab tests performed at reservoir stress conditions which aim to simulate the behaviour of the reservoir during a production/depletion cycle (and potentially injection). The experiment in performed under the following conditions:

•The vertical stress corresponding to the overburden weight is kept constant,

•Horizontal stress corresponding to reservoir conditions is initially applied and then displacements on the sides of the sample are fixed so the sample diameter is held constant

•Initial pore pressure of the reservoir is applied and then it is decreased to simulate drawdown due to production.

 

Under such conditions uniaxial compaction occurring on reservoirs during production can be replicated on the lab. Hence porosity and permeability reduction with pore pressure decrease will occur.

 

The experiment will be simulated by considering a plane strain single element of dimensions 10 x 10 m to which arbitrary experimental conditions will be applied. A history point on a corner will be used to output evolution of the state variables (properties) during the simulation.

 

 

                       

Schematic of experiment conditions (left) and geometry considered for the simulation (right)

 

 

Simulation Cases

 

Case 1 Poroelastic material

 

Case 2 Poro-elasto-plastic material (SR4)