Intelligent drainage and mining method of coalbed methane well and intelligent drainage and mining equipment of coalbed methane well immersed pump

Abstract

The invention discloses an intelligent drainage and mining method of a coalbed methane well and intelligent drainage and mining equipment of a coalbed methane well immersed pump. The intelligent drainage and mining method is realized as follows: in the pumping and sucking process, liquid the water quality of which confirms to requirements is supplied for underground liquid by a set flux when a liquid replenishing condition is met so that the height and the descent speed of an underground liquid level as well as the viscidity and the output of the underground liquid all confirms to the normal drainage and mining requirement. The drainage and mining equipment comprises a drainage and a water replenishing device; the water replenishing device consists of a water supply device and a water replenishing pipe, wherein the water supply flow of the water supply device is controlled by a control cabinet, the water replenishing pipe is connected with a water outlet of the water supply device, and the outlet of the water replenishing pipe is arranged near an underground immersed pump. The intelligent drainage and mining method and equipment can continuously replenish, release and drain liquidaccording to the well condition, thereby solving the problems that a submergible motor is easy to burn out due to deteriorative radiating condition and the pump is easy to clamp and burn due to viscid liquid under the conditions that the liquid supply of a coalbed methane reservoir is lowered, the coal ash content of liquid is increased and the tonnage is lower; in addition, the periods for sand bailing and pump inspection are prolonged.

Description

technical field [0001] The invention relates to the technical field of water drainage and gas recovery for coalbed gas wells. Background technique [0002] The development of coalbed methane can make up for the serious shortage of clean energy in my country, improve the energy structure, curb coal mine gas disasters, reduce the direct emission of methane in the coal mining process, and improve the quality of the atmospheric environment. In the prior art, there is a method and equipment for drainage and gas recovery that realizes the discharge of gas in the coal seam by water pumping the drainage and depressurization of coalbed methane wells. The water pumps used in the existing coalbed gas drainage include pumping unit type piston pumps and submersible centrifugal pumps. However, compared with pumping unit piston pumps, centrifugal pumps have the advantages of lower requirements on the verticality of the wellbore, easy maintenance, low energy consumption, and continuous pump...

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Problems solved by technology

[0003] The existing coalbed methane drainage and gas recovery technology using frequency converters and submersible electric pumps can only control the amount of liquid production. When water is pumped outward, the downhole pressure will also decrease with the increase of the displacement. Excessive drainage speed will cause the formation pressure to drop too fast, and the reservoir with strong stress sensitivity will be very prone to velocity sensitivity and cause the coalbed methane wellbore The nearby coal reservoirs were seriously damaged in a short period of time, resulting in a sharp decrease in the permeability of coalbed methane, which hindered the expansion of the pressure-reducing funnel of coal reservoirs, and the large-scale desorption of coalbed methane was unable to form a long-term stable production of single well specifications. The frequency converter in the prior art uses frequency conversion to change the rotation speed and displacement, which is trapezoidal control, and the drop rate of the liquid level cannot adapt to the changes in the stress sensitivity of the formation during the drop process. In addition, there are strong stress sensitivity and low permeability in China's coal seams. characteristics, the use of existing coalbed methane drainage equipment is very easy to damage the reservoir; (2) when the drainage time is long, the discharge of downhole liquid will decrease due to the reduction of reservoir liquid supply. Hours, the frequency conversion technology has a limited ability to adjust the speed of the motor. Even if the speed of the submersible motor is reduced to the minimum, it cannot meet the minimum displacement requirements required for production, and the heat transfer efficiency of the discharged liquid as the heat transfer medium of the submersible motor is also low. Correspondingly, this will lead to poor heat dissipation conditions of the submersible motor and easy to burn out. (3) With the increase of displacement time, the water supply of the reservoir gradually decreases, and the proportion of coal ash in the downhole fluid is increasing, and the downhole fluid The viscosity will also increase, which is not conducive to outward drainage and will affect the smooth operation of the pump or even damage the pump. If the pump is damaged, it is necessary to check the pump to remove sand and increase the cost, and frequent workover will easily cause reservoir damage and further affect production.

[0004] In addition, the downhole sensor and the control cabinet of the existing drainage equipment are connected by a special signal transmission cable suspended. The signal transmission cable is long and often rubs against the well wall or other equipment. The signal transmission line The cable is easily damaged, causing the sensor signal to fail to transmit normally and affecting production

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