Vasquez and Beggs Oil Compressibility correlation

Vasquez and Beggs Oil Compressibility correlation

Vasquez and Beggs is an empirical correlation for the oil compressibility published in 1980.

Vasquez and Beggs Oil Compressibility correlation in the PVT Software

Math & Physics

$c_o = \frac{28.1R_s+30.6T-1180SG_g+\frac{1784}{SG_o}-10910}{10^5P}$

Example. Calculation of the oil compressibility

Example source

Input data

$R_s$ = 53.24 sm³/sm³ at P = 10 MPa

$SG_o$ = 0.85 or 35 API

$SG_g$ = 0.75

Calculate oil compressibility at p = 10 MPa?

Solution

$c_o$ = 0.002912 MPa^-1 or 2.95E-4 atm

The solution is available in the online PVT calculator software model at www.pengtools.com

Application range

$2.35 \le R_s \le 322$

$0.754 \le SG_o \le 0.989$

$0.555 \le SG_g \le 1.245$

$21.1 \le T, C \le 160$

Nomenclature

$B_o$ = oil formation volume factor, rm³/sm³

$R_s$ = solution gas-oil ratio, sm³/sm³

$SG_g$ = gas specific gravity, dimensionless

$SG_o$ = oil specific gravity, dimensionless

$\rho_{oR}$ = oil density at reservoir conditions, kg/m³

$\rho_{STO} = SG_o \times 1000$ = stock tank oil density, kg/m³