Liquid loading

Brief

Liquid loading is a phemonenon when the gas phase does't provide sufficient transport energy to lift the liquids out of the well.

Math & Physics

The minimum gas velocity to remove the liquid equation:

$v_g = 1.593 \sigma^{1/4} \frac{({\rho_L-\rho_g})^{1/4}}{\rho_g^{1/2}}$

The minimum gas rate to remove the liquid equation:

$q_g = 3.06 \frac{P v_g A}{T z}$

Nomenclature

$v_g$ = gas velocity, ft/sec

$\sigma$ = surface tension, dyne/cm

$\rho_L$ = liquid density, lbm/ft3

$\rho_g$ = gas density, lbm/ft3

$P$ = flowing pressure, psia

$q_g$ = gas rate, MMscf/d

$A$ = flow area, ft^2

$T$ = flowing temperature, /deg R

$z$ = gas compressibility factor at flowing P & T

References

Turner, R. G., Hubbard, M. G., and Dukler, A. E. (1969) “Analysis and Prediction of Minimum Flow Rate for the Continuous Removal of Liquids from Gas Wells,” Journal of Petroleum Technology, Nov. 1969. pp. 1475–1482.