Tubing Depth Optimization Study of Horizontal Well Drainage and Gas Production in WeiYuan Shale Gas Field

Abstract

Timely production with a tube in shale gas wells can effectively ensure the stable decline of gas wells. However, there is no in-depth study on which position of tubing is the most favorable for the stable production of gas wells and whether the wellbore trajectory has an impact on this position. To determine the reasonable end of tubing (EOT), firstly, through the gas water flow experiment of the whole wellbore test device of a horizontal well, the characteristics of liquid accumulation in the test section and the liquid discharge at the outlet are analyzed. The results show, when the horizontal section inclines upward and the end of the tubing reaches 1/3 of the horizontal section, the gas flow carrying liquid is the smallest. Then, OLGA software is used to simulate the wellbore effusion in the production process of gas wells with different tubing depths under different wellbore trajectories. The results show when the horizontal section inclines upward and the end of the tubing arrives at 1/3 of the horizontal section, the cumulative production of the gas well is the largest. Based on comprehensive analysis, it is most favorable for horizontal shale gas wells when the end of the tubing is about 1/3 of the horizontal section.