Valko - McCain bubble point pressure correlation

Brief

Valco- McCain correlation is ...

Math & Physics

$z1 = -4.814074834 + 0.7480913 \times log(R_{sb}) + 0.1743556 \times (log(R_{sb}))^2 - 0.0206 \times (log(R_{sb}))^3$

$z2 = 1.27 - 0.0449 * $API + 0.000436 * pow($API, 2) - 0.00000476 * pow($API, 3)$

$z3 = 4.51 - 10.84 * SG_{g} + 8.39 \times SG^2_{g} - 2.34 * SG^3_{g}$

$z4 = -7.2254661 + 0.043155 \times T - 8.5548e-5 \times T^2 + 6.00696e-8 * T^3$

$z = z1 + z2 + z3 + z4$

lnPb = 2.498 + 0.713 * $z + 0.0075 * pow($z, 2);

Bubblepoint_Valko_McCainSI = exp($lnPb);

where:

Nomenclature

$A_1..A_{11}$ = coefficients

$\rho_r$ = reduced density, dimensionless

$P$ = pressure, psia

$P_{pc}$ = pseudo critical pressure, psia

$P_{pr}$ = pseudoreduced pressure, dimensionless

$SG_g$ = gas specific gravity, dimensionless

$T$ = temperature, °R

$T_{pc}$ = pseudo critical temperature, °R

$T_{pr}$ = pseudoreduced temperature, dimensionless

$z$ = gas compressibility factor, dimensionless