在煤层气井排采过程中，通常用回声仪来监测环空液面变化，通过控制液面下降速度来实现稳定、连续降压。
The echometer was used to monitor the change of the annular water level in the coal- bed methane(CBM)wells production, which could decrease pressure stably and continuously.
在煤层气井排采过程中，通常用回声仪来监测环空液面变化，通过控制液面下降速度来实现稳定、连续降压。
Changes of liquid level are usually monitored with echometers and stable decompression is achieved by controlling the reducing rate of the liquid level.
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