煤层气井动液面测算误差分析及新型考克设计

Error Analysis of Dynamic Liquid Level in CBM Well and New Design of Cock

井底流压是指导煤层气排采工作的重要参数,生产中常需要用动液面估算井底流压。为了获取相对准确的动液面数据,通过总结现场经验,分析认为动液面测算的误差主要有以下来源:①井口自激波;②回音标过浅;③解释方法不统一;④上组煤干扰;⑤泡沫段干扰,并提出相应的解决方案。另外,根据现场工作特点,设计制造了一种新型考克,经实践证明,作业时间缩短了28.6%,有效地提高了工作效率。

Bottom-hole pressure is an important parameter for guiding CBM production. During the pro- duction process, it is needed to use the dynamic liquid level to estimate the bottom-hole pressure. In or- der to gain relatively accurate liquid level date, by summarizing the experience in practice, the analysis in the paper shows that the errors are mainly derived from the following sources：①self-excitation wave; ②shallow reflector; ③ calculation method is not uniform; ④ the interference of up seam; ⑤ the interference of foam segment. Correspondent solutions are also proposed. In addition, a new type of cock are designed and manufactured according to the characteristics of site work. It is proven that the working time has been shortened by 28.6% , which effectively improves the work efficiency.