Page 206 - Primer on Enhanced Oil Recovery

194 Primer on Enhanced Oil Recovery

Fluid and reservoir Screening criteria Screening
properties. Field results
under study (field a) Taber-Seright
(1997)
Viscosity, cp 500 < 100000 1
API Gravity, ºAPI 14 8–25 1
Current Oil Saturation, 0.6 > 0.4 1
fraction
Thickness, ft 120 > 20 1
Permeability, mD 150–300 > 200 0.6666 Score for each property
Porosity, fraction 0.38–0.52 NC 1
Depth, ft 2900–3200 < 5000 1
Pressure, Psia 600 NE
Lithology Sandstone (SS) NE
0.9524 Score of the method

Figure 16.1 An example of simplified technical screening.

Properties of reservoir fluids are necessary for:
oil and gas reserves estimation,
well production rate forecast,
field development design
hydrodynamic field modeling.

The data allow to see at which PVT conditions the fluid can be a single phase or
will separate into multiple components. This is especially important as simple equa-
tions, like Darcy’s flow rate, only applicable to the single phase flow. Multiphase
flow is described by much more complex than Darcy’s equations.
The main parameters determined by PVT analysis for reservoir oil are:

Oil saturation pressure with gas, methods of contact and differential degassing;
Measurement of density of reservoir oil;
Measurement of viscosity of reservoir oil;
Paraffin crystallization temperature.
The main parameters determined by PVT analysis for a reservoir gas (gas con-
densate) are:

The pressure of the onset of retrograde condensation;
Measurement of the density of gas and gas condensate;
Measurement of reservoir gas viscosity.
Laboratory analysis and thermodynamic modeling require specialized hardware,
software and skillful personnel. There are many laboratories and companies special-
izing on properties analysis. It is probably possible to say that the consultancy