An underground pump monitoring device for coalbed methane drainage and gas recovery

Abstract

The invention relates to an underground along-pump monitoring device for coal bed gas water discharge and gas production. The device comprises an underground along-pump monitoring device and a groundcollection transmission system, wherein the underground along-pump monitoring device comprises an underground armored cable, a cable connecting hoop, a transition nipple, an ultrasonic coal powder concentration monitoring nipple, an underground circuit nipple, a pressure temperature monitoring nipple and an in-pump perturbation assembly, wherein the underground along-pump monitoring device is provided with a fixing valve, and is connected under a pump tube of a conventional water discharging pump; the ground collection transmission system supplies electricity for the along-pump monitoring device; the underground circuit nipple controls the pressure temperature monitoring nipple and the ultrasonic coal powder concentration monitoring nipple to monitor the temperature, pressure and coal powder impurity concentration change quantity in a position near the water discharging pump suck-in opening; the dynamic liquid level depth is calculated according to the pressure value; signals treated by an underground main control unit are transmitted to a well field monitoring center; when the coal powder concentration rises, the perturbation impeller rotates; the cyclone liquid carriers the coalpowder impurities to be discharged out of a pump cavity; the active cleaning in the pump and the underground parameter online monitoring are realized.

Description

technical field [0001] The invention belongs to the technical field of downhole online monitoring of coalbed methane drainage and gas recovery, and in particular relates to an underground pump monitoring device for coalbed methane drainage and gas recovery. The pump monitoring device for real-time monitoring of key parameters such as temperature, pressure, dynamic liquid level and coal powder impurity concentration in coalbed methane drainage and gas production wells. Background technique [0002] At present, in the construction of intelligent well completion for coalbed methane production in my country, the automatic collection of surface parameters has been basically realized for production wells, but there is a lack of effective automatic monitoring and collection methods for downhole key parameters. In particular, parameters such as the pressure, temperature, and impurity content of the fluid around the reservoir during the drainage and gas recovery of coalbed methane ar...

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Problems solved by technology

Among them, the change of impurity content in pulverized coal near the reservoir is a direct guiding factor to reflect the degree of damage to the desorption gap of the reservoir and to verify the rationality of the drainage system. At present, there is no feasible downhole direct monitoring method, and parameters such as temperature and pressure are mainly monitored through the wellhead. The disadvantage of indirect calculation of data or monitoring by production logging is that the former cannot accurately reflect the real parameter changes at the bottom of the coalbed methane wellbore, and the latter cannot be monitored online for a long time. Desorption gaps in the formation are destroyed, and the pulverized coal pours into the wellbore to block the drainage pump, resulting in frequent workover operations, shutting down the gas well, and high maintenance costs; 2) After the reservoir is damaged, the stable and continuous drainage production in the later stage will be affected, and the gas production will drop sharply , and the damage to the coal reservoir cannot be repaired

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