Understanding Heel Dominant Liquid Loading in Unconventional Horizontal Wells

Abstract

As a common occurrence in production operations, liquid-rich horizontal gas (and gassy oil) wells in unconventional plays develop severe instabilities at different stages of their well life. In this novel work, we first quantify the three-phase gas-oil-water multiphase flow behavior leading up to the characteristic severe loading signatures in order to better understand the dynamic heel-dominant liquids loading. Then, we demonstrate how a simple analytical diameter-and-inclination-dependent critical gas velocity equation can be used to determine the onset of the severe loading instabilities in a variety of artificial lift/liquid loading mitigation strategies, namely end-of-tubing landing (EOT), tubing/casing sizing, gas lift variations and tail pipe/dip tube. Actual high frequency bottom hole pressure data along with measured surface conditions will be used to evaluate the slugging behavior and recreate using analytical multiphase flow simulator. The flow conditions will be extrapolated to the heel/near lateral section of the well and simulated for various lift strategies.

Investigating the Impact of Undulation Amplitude of Unconventional Oil Well Laterals on Transient Multiphase Flow Behavior: Experimental and Numerical Study

“…Slugging is an undesired phenomenon creating flow instabilities, which can impair the performance of liquid-producing wells, as shown in [1,5,6], which also has implications for gas-well liquid-loading studies, as shown in [7][8][9][10][11][12][13][14], and CO 2 storage due to wellbore phase change, as shown in [15][16][17][18][19][20][21].…”