Technology of integrating drainage, gas production and coaldust bailing for coalbed methane vertical wells

During extraction of coalbed methane well, the most used method is pumping unit discharge and extraction system. The conventional mono-barrel pump is usually used as the discharge and extraction pump; the main problem of this pump is that pump is stuck by coal dust with standing valve and traveling valve are also stuck by coal dust, leading to frequent operation of the system and severely affecting the production efficiency of coalbed methane. In order to effectively solve this problem, a set of string integrating discharge, extraction and bailing of coal dust has been developed, which uses new coal dust-proof pump and basket settling pipe, making it possible to integrate discharge, extraction and sand bailing in coalbed methane wells. The new coaldust-proof pump utilizes long plunger structure with highly standing valve and large-diameter travelling valve, which cannot only effectively prevent coaldust from sticking the standing valve and travelling valve, but also effectively prevent coaldust from entering pump barrel and causing stuck pump. The coaldust deposited during discharge and extraction goes into the basket sand setting pipe, which will be removed together with coaldust deposited in the sand setting pipe during pump inspection, diminishing the work of bailing coaldust and saving the cost. Field application shows that the pipe string integrating coalbed methane discharge, extraction and coaldust bailing by vertical well can meet the site requirement, extend the pump inspection cycle and has good promotion prospect.