Unblocking experiment of coal fines clogging screen tube by ultrasonic technology

Abstract

In the process of coalbed methane exploitation, the problem of coal fines blocking the screen tube seriously affects the continuous and stable drainage and production of coalbed methane wells. Aiming at the problem of clogging the screen tube with coal fines, the method of using ultrasonic technology to unblock the screen tube is proposed. The experiments of unblocking the screen tube blocked by coal fines with different particle sizes and compositions are carried out, and the unblocking effect and influencing factors of ultrasonic technology on the screen tube are discussed. The results show that with the increase of coal fines particle size（＜63 μm, 63-125 μm and >125-300 μm）, the specific surface area of coal fines decreases, the adhesion of coal fines decreases, and the effect of ultrasonic technology on screen tube blockage removal increases. Kaolinite can improve the hydrophilicity of coal fines. With the increase of the proportion of kaolinite in coal fines, the hydrophobic attraction between coal fines particles decreases, the adhesion of coal fines decreases, and the effect of ultrasonic technology on screen tube unblocking is enhanced. The action time of ultrasonic technology for blocking removal is within 0-30 min. With the increase of ultrasonic action time, the efficiency of ultrasonic blocking removal decreases. Among them, the action time is most obvious in the time period of 0-10 min. It is recommended that the action time of ultrasonic blocking removal is longer than 10 min.

Keywords

• coalbed methane
• coal fines
• ultrasonic technology
• screen tube
• unblocking