Automatic intermittent coal bed gas draining and generating method and device thereof

Abstract

The invention discloses an automatic intermittent coal bed gas draining and generating method and a device thereof. The automatic intermittent coal bed gas draining and generating method includes that: (1) a flexible rod and an elastic piston are driven to move downwards in a pump cylinder by forward rotation of a reciprocating driving device, at this moment, a valve ball of a valve is positioned on a valve seat, and the valve is closed to enable water entering an oil tube and the pump cylinder after flowing through a sleeve, a screen tube and the valve to be sealed in the oil tube; (2) when the elastic piston reaches onto an upper adapter, the reciprocating driving device is stopped, the flexible rod is driven by backward rotation of the reciprocating driving device to drive the elastic piston to move upwards to push the water in the pump cylinder out, at this moment, vacuum is formed between the elastic piston and the valve, the valve ball is flushed upwards by action of the water, and the water enters the sleeve via an ejection hole of the sleeve from a ground layer and then enters the oil tube via the screen tube and the valve; (3) the steps (1) and (2) are repeated for draining coal bed gas . By the aid of the automatic intermittent coal bed gas draining and generating method and the device thereof, efficiency of a water pump is increased to 90%, and good stability is achieved.

Description

technical field [0001] The invention belongs to coalbed methane well drainage equipment and an operation method. Background technique [0002] Coalbed methane, commonly known as gas, is an unconventional natural gas formed in the coal formation process and existing in the coal seam. Most (70%-90%) of this natural gas exists in the coal-rock matrix in an adsorbed state, and a small amount of it forms. The free state exists in coal cleats and other pores and fissures, and a little is dissolved in coal seam water. [0003] First, CBM is a new type of clean energy and high-quality chemical raw materials. In order to make full use of CBM to the ground, it is necessary to reduce the reservoir pressure by means of drainage and pressure reduction. - The process of desorption-diffusion-seepage. [0004] In the process of CBM exploitation, ensuring the stable discharge of confined water in the coal seam is the most important guarantee for a single well of a CBM well to achieve large...

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Problems solved by technology

Although this structure can realize drainage, but there is a single extraction volume that is too large, causing the liquid level of the casing to fluctuate violently, resulting in the coalbed gas not being fully decomposed from the coal seam, or even unable to be decomposed

Compared with the production of oil wells, the properties of the drainage fluid change, and the water cannot form a lubricating oil film during the suction process to protect the friction between the rubber sleeve and the inner wall of the tubing. The effective working time of the rubber sleeve is too short, which seriously affects the normal drainage. Pick

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