Practical Use of Recent Research in Multiphase Vertical and Horizontal Flow

Abstract

A recent correlation for multiphase vertical flow hy Hagedorn and Brown'·1 has been used to examine the ef- fect of numerous Wlriables such as pipe size, gas-liquid ratio, liquid flow rate, liquid viscosity, liquid surface ten- sion, oil API gravity, water cut, etc., on flowing pressure gradients. Most previous correlations were derived by using a form of the general energy equation which assumed negligible changes in kinetic energy. Under certain flow conditions this can lead to serious errors in predicting pressure tra- verses. Examples of traverses calculated both with and without the kinetic energy term are included here. The Chew and Connally correlation for calculating changes in viscosity with changing pressure and tempera- ture has been extended so that the effect of a changing vis- cosity with depth on pressure gradients can also be predict- ed. Examples illustrating the effect of tubing size show the importance of this correlation in determining pipe sizes for initial well completions. Limitations on production rates in small pipe sizes from excessive friction losses can be predicted with greater accuracy. The combined use of a vertical-flow correlation with a horizontal-flow correlation provides a method for determin- ing the maximum flow rate possible from both flowing and gas-lift wells. Examples are included to illustrate application of the combined use of vertical and horizontal-flow correlations in optimizing production rates and minimizing excessive costs from over injection of gas in gas-lift wells.