煤层气井有杆泵内煤粉沉积的影响因素分析

依据固液两相流理论，建立了煤层气井煤粉在有杆抽油泵内的数学模型，对煤粉在泵内的运动规律进行了分析，通过求解煤层气井有杆泵内固液两相流模型及仿真分析，得到了煤粉颗粒直径、井液的入泵速度及井液中煤粉颗粒浓度等参数对有杆泵内煤粉沉积的影响，利用固体颗粒在泵筒和柱塞间隙的磨损特性，分析了煤粉对有杆泵使用寿命的影响并给出了延长检泵周期，提高泵的使用寿命的措施。结果表明：有杆泵内下端煤粉浓度较大，分布非常不均匀；有杆泵内煤粉颗粒速度分布不均匀，湍流现象比较严重，煤粉颗粒主要沉积在固定阀入口两侧。煤粉粒径越小、井液入泵速度越大和井液中颗粒浓度越小可减少煤粉在有杆泵内的沉积。在排采的过程中通过连续、稳定、缓慢的降压，减少储层出煤粉；合理调节排采系统的冲程、冲次，通过改变泵的排量提高泵入口的流速，可减小煤粉在有杆泵内的沉积，使进入泵中的煤粉尽量排出泵外进入抽油杆和油管环空，以减少煤粉对有杆泵的影响。

Movement of Pulverized Coal in Sucker Rod Pump in Coalbed Methane Well

Based on the solid-liquid two phase flows theory, the mathematical model of coal particles in sucker rod pump was built, and the motion law of coal particles in sucker rod pump was analyzed. Through the model and simulation analysis of the solid-liquid two phase flows in sucker rod pump, the influence of the parameters, including the diameter of coal particles, the inlet velocity of well fluid, and the concentration of coal particles in well fluid, on coal particles deposition in sucker rod pump was obtained. Based on the wearing character of solid particles in the space between pump barrel and plunger, the influence of coal particles on service life of sucker rod pump was analyzed and the measures to prolong the detection period and service life of pump was given. The results show that the concentration of coal particles in the bottom of pump is relatively big and the distribution is very uneven. In sucker rod pump, the velocity distribution of coal particles is uneven and the turbulence is obvious, with coal particles mainly depositing along the entrance of the standing valve. A smaller diameter of coal particles, bigger inlet velocity of well fluid, and smaller concentration of coal particles in well fluid can reduce coal particles deposition in sucker rod pump. In the process of production, a continuous, stable and slow depressurization can reduce the production of coal particles. The reasonable adjustment of stroke and rate of production system and improvement of inlet velocity by changing pump capacity can reduce the coal particles deposition in sucker rod pump, making the coal particles in sucker rod pump discharged into the annulus between pumping rod and tubing, and the influence of coal particles on the pump can be significantly reduced.