Paper: Application of Gas Lift For Small Diameter Tubing Installations

The increase in small diameter casing completions has increased the use of small size tubing. Gas lift would be the most suited method of artificial lift in many installations where it has not been used due to the unavailability of accurate flowing pressure gradient traverses for small conduits. Initial evaluation of gas lifting through small tubing using calculated pressure gradients based on the extrapolation of a widely accepted two-phase energy loss correlation eliminated the feasibility of gas lift. The calculated pressure gradients were much higher than actually exist. Experimental data has be gathered recently for single- and two- phase flow through small conduits. This data has been correlated into usable flowing pressure gradient traverses for small tubing and pressure loss due to friction curves for gas flow through small configurations. Two-phase flowing pressure traverses for 1- and 1-1/4-inch nominal tubing are presented for the design of continuous flow gas lift installations and prediction of maximum producing rates from wells with small tubing. Curves for gas flow are offered for calculation of the friction portion of the pressure loss is small tubing and annuli.