煤层气井射流冲煤粉装置冲击深度的研究

The impinging depth of coal particles cleanout jet device for coalbed methane well

为确定煤层气井射流冲煤粉装置合理的结构和工作参数,实现射流冲煤粉系统的优化设计和有效运行,理论分析了冲煤粉装置工作原理和煤粉颗粒运动过程,整个井底冲煤粉射流场可分为:自由射流区、射流冲击区、漫流区、返流区、旋涡区和负压吸附区6个区域,决定煤粉是旋转上升的复杂运动状态。开展均匀设计方法的冲煤粉实验,运用二次多项式逐步回归法得出回归方程,揭示喷嘴结构参数、射流参数和煤粉特性对冲煤粉深度的互相耦合的影响关系。结果表明,对冲煤粉的深度影响程度的大小依次为:喷距、喷嘴直径、喷嘴流量和煤粉直径。进一步的单因素试验详细了解各影响因素对冲煤粉深度的影响,得出在要求不动管柱时冲煤粉深度达到500 mm的条件下,喷嘴流量不能低于15 m3/h,喷距应小于100 mm。

In order to determine the reasonable structure and working parameters of coal particles cleanout jet device in coalbed methane wells, and realize the optimization design and efficient operation of coal particles cleanout jet system, theory analysis on the working principle of coal particles cleanout and motion process of coal particle was done. The bottom hole coal particles cleanout jet flow field can be divided into six areas ：free jeting area,jet impinging area, ra- dial flowing area, reflux area, vortex area and negative pressure suction area ,which resulted in the spiral uprising mo- tion state of coal particle. Coal particles cleanont experiments were designed by uniform design method, regression equation was found by quadratic polynomial stepwise regression method, the intercoupling influence relation of nozzle structure parameters ,jet parameters and coal particle characters to impinging depth was revealed. The results show that the arrangement of these parameters is jet distance, nozzle diameter, nozzle flow rate, and coal particle diameter accord- ing to their effects on impinging depth. The influence of nozzle flow rate, nozzle diameter and jet distance on impinging depth was obtained in detail by further single factor experiment, and got the conclusion that on the condition that im-pinging depth reached 500 mm without moving the tubes,the nozzle flow rate can＇ t be lower than 15 m3/h ,and the jet distance should be less than 100 mm.