Advanced Rock Properties – Pore Volume Compressibility
Pore Volume Compressibility: UPVC, HPVC and RTCM
Applications of PVC Data:
- Drive mechanism determination
- Recoverable reserves determination
- Subsidence prediction
- Reservoir compaction conditions
- Horizontal permeability analysis
Advantages of UPVC:
- Simulates actual reservoir production stress path
- Accounts for inelastic behavior of reservoir rock
- Measures compaction directly from axial strain
- Obtains compressibility as a function of pore pressure
- Differentiates horizontal from overburden pressure
Rate Type Compaction Method (RTCM)
First demonstrated by Waal and Smits in 1988, RTCM testing describes reservoir compaction non-linearity.
Hydrostatic Pore Volume Compressibility (HPVC)
HPVC Pros:
- Simple, easy to perform
- Quicker data at low cost
UPVC Apparatus
RTCM Forecast
Production rates change over the life of a field. Rate Type Compaction Method testing is used to obtain compaction as a function of production rates.
HPVC Cons:
- Doesn’t simulate reservoir stresses
- Indirectly estimates compressibility from the volume of expelled water
- Assumes the sample is isotropic
- Requires a Poisson’s ratio dependent correction to guess uniaxial values