煤层气井筒单相流阶段煤粉动态沉降规律

    Dynamic settlement law of coal powder during single-phase flow stage of coalbed methane wellbore

    • 摘要: 针对煤层气开发过程中部分煤层气井煤粉产出严重的问题,研发了一套煤粉动态沉降实验平台;根据现场煤层气井排采工况和煤粉产出特征,设计了符合现场生产特征的实验条件,探讨了煤层气井在单相流阶段煤粉的运移沉降规律。结果表明:音叉谐振密度传感器可以实现井下煤粉质量浓度的实时监测;当流体速度大于等于0.020 m/s时,180~250 μm的煤粉颗粒会被携带运移;当流体的速度大于等于0.010 m/s时,150~180 μm的煤粉颗粒会被携带运移。在煤粉质量浓度一定的情况下,流速的增加会引起井筒内煤粉质量浓度值的增加,证明了增加排水速度有助于把井下沉降的煤粉排出井筒。

       

      Abstract: In response to the severe problem of coal powder production in some coalbed methane wells during the development process of coalbed methane, a set of coal powder dynamic settlement experimental platform as been developed; based on the on-site production conditions of coalbed methane wells and the characteristics of coal powder production, experimental conditions were designed to meet the on-site production characteristics, and the migration and settlement laws of coal powder in the unidirectional flow stage of coalbed methane wells were explored. The results show that the tuning fork resonant density sensor can achieve real-time monitoring of underground coal powder mass concentration; 180-250 μm coal powder particles will be carried and transported when the fluid velocity is greater than or equal to 0.020 m/s; 150-180 μm coal powder particles will be carried and transported when the fluid velocity is greater than or equal to 0.010 m/s. When the mass concentration of coal powder is constant, the increase in flow rate will cause the increase in the mass concentration of coal powder in the wellbore, which proves that the increase of drainage speed is helpful to discharge the settled coal from the shaft.

       

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