OVERVIEW

Fluid properties are important for both reservoir and production system calculations.

1. For reservoir performance studies, fluid properties are needed at reservoir temperatures and pressures.

2. For wellbore hydraulics, fluid properties are needed at various temperatures and pressures.

This appendix is divided into the following sections:

1. Evaluation of PVT properties

2. Oil properties and correlations

3. Gas properties and correlations

4. Water properties and correlations

EVALUATION OF PVT PROPERTIES:

Fluid properties can be evaluated by the following two methods:

1. Laboratory PVT Analysis

   Disadvantages Usually conducted at reservoir temperatures.

   • May not be available early in life of reservoir (for economic reasons).

2. Empirical Correlations

   • Based on laboratory PVT analyses from various fields around the world.

   • Can be applied to wide ranges of pressures, temperatures and oil properties.

OIL PROPERTIES AND CORRELATIONS

1 OIL DENSITY

Symbol: ? ₀

Units lbm/ft ³, gm/cc, API

Definition

CORRELATION

where:

• ? _o = oil density, lbm/ft ³

• ? _o = oil specific gravity, dimensionless

• ? _g = gas specific gravity, dimensionless

• R _s = solution or dissolved gas, SCF/STB,

• B ₀ = oil formation volume factor, RB/STB,

If ? > ? _b, the bubble-point pressure, then

where

• ? _o = oil density at ?, T, gm/cc

• ? _ob = oil density at ? _b, T, gm/cc

• ? = pressure, psia,

• T = temperature of interest, F

• ? _b = bubble-point pressure at temperature T, psia,

• c _o = oil isothermal compressibility at