煤层气井不同类型煤粉的静态沉降规律

为研究卡泵煤粉的粒径大小，减少卡泵事故的发生。通过煤粉粒度分析实验确定了造成卡泵的煤粉粒径主要在小于0.037 4 mm和大于3.8 mm的范围，进一步利用激光粒度分析仪分析，缩小了造成危害的细煤粉粒径范围;针对粒径小于0.037 4 mm的煤粉进行静态沉降速度测定实验，发现当煤粉浓度很小时，沉降速度随浓度的增加急剧减小，当浓度继续增大时，煤粉的沉降速度将不再变化，趋于一个常值。同时通过测定不同粒径煤粉和不同浓度煤粉的悬浮率，发现煤粉浓度越低，煤粉的悬浮率越高;在对不同煤粉的润湿性实验中发现与排采样相比，钻屑样润湿性差，但润湿改造效果较好。依据实验结果，总结了细煤粉的基本物理特性以指导预防煤层气井中卡泵等事故的生产措施。

Static settlement of different types of pulverized coal in CBM wells

In order to study the particle size of the pulverized coal that bring trouble to pump and reduce pump accident.The size analysis of drilling cuttings finds that the fines less than 0.0374 mm and more than 3.8 mm are the main particle for stuck pump,plug pump or plug shaft.Further study narrows the size range by means of LPSA(Laser Particle Size Analyzer).In the static settling velocities experiment,it is found that when the concentration of fines is very low,settlement velocity decreases with the increase of concentration.When the concentration is increased,coal settlement rate will no longer change and tend to a constant value.It is also found that the lower of concentration of fines,the higher of coal suspension rate.In the wetting experiments of different pulverized coal samples,it is found that the wettability of fine sample of the drilling cuttings is poorer than that of sample of output of drainage,but the wetting modification effect of fine sample of the drilling cuttings is better.According to the experimental results,the basic physical characteristics of fines are summarized in order to guide the production of fines in the coalbed methane well.