SU1500792A1 - Method of degassing coal seam - Google Patents

Description

The invention relates to the mining industry. The goal is to increase ”ef2

the efficiency of coal seam degassing. From the surface to the coal seam. drill wells. They pump the working fluid at a rate exceeding the natural injectivity of the reservoir.

The working fluid is kept until the formation of a system of hydro-conductive cracks. In the process of pumping fluid determine the flow rate of the gas mixture. After stabilization of water and gas generation, the first preparatory development is carried out in the humidification zone. From it, the reservoir drainage wells are drilled to both sides and methane suction is carried out. Subsequent development is carried out in an array degassed in

surface and reservoir wells- ®

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The invention relates to the mining industry and can be used for the degassing of high-gas outburst coal seams with low natural permeability.

The purpose of the invention is to increase the efficiency of coal seam degassing.

Fig, 1 shows the location of the drainage wells and development workings; in fig. 2 - zones formed in the reservoir around the well-. here are hydrologic sections; in fig. 3 - the nature of water-gas removal from the treated area through the well of dismemberment.

The method is implemented as follows.

From the day surface to the coal seam, · Boreholes 1 are drilled (FIG. 1) through which the formation is treated with a working fluid (solutions of surface and chemically active substances) at a rate exceeding the natural injectivity of the formation. After hydraulic dissection, three zones are formed around the well (FIG. 2): I is a hydraulic dissection zone, in which, in addition to the fracture opening, the reservoir is saturated with water; II - a zone of moistening in which the working fluid moves in the filtration mode and the opening of natural cracks does not occur; III - zone of natural permeability and reservoir moisture.

After the end of the formation treatment, the well is opened,

s 1500792

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most of all they release pressure in it and start pumping out the working fluid, during which the flow rates of the water-gas mixture from the treated area are measured. When pumping fluid from the well, the pressure at its bottom becomes equal to the atmospheric pressure and the formation pressure on the treated area is equalized from the value P ⁿ (see figure 2) to the value. Control of pressure equalization is carried out indirectly on the basis of measurements of the flow rates of the water-gas mixture from the treated area. At the initial moment of time, after the pressure in the well is released and the water is pumped out of it due to a significant excess of p / atmospheric pressure, there is an intensive release of water and gas from zone I to the well. Then, as the value of P ** decreases to the value, stabilization of water-gas emission occurs (see Fig. 3), while the nature of water and gas output is calm.

After stabilization of water and gas gaps from the treated area (equalization of reservoir pressure), the first preparatory production 2 from slope 3 (see Fig. 1) is started in the wetting zone II (see Fig. 2), since in this case the wetting zone is a natural barrier, preventing the flow of gas from the surrounding array into the production by blocking it in the pores and cracks with liquid. As production 2 is made from it, reservoir degassing wells 4 are drilled to both sides, and subsequent production 5 and 6 are carried out in a degassed array after extracting the required amount of methane through surface and subsurface wells.

Using the proposed method of degassing will allow in comparison with the known increase in efficiency

Ιθ degassing preparatory workings 1.7-2.5 times, the speed of the workings on gas-bearing formations by 20-40%, while the cost of their conduct is reduced by 10-20%.

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Claims (1)

Claim Method of coal seam degassing, including drilling wells 20 surfaces onto a coal seam, injecting a working fluid in them at a rate exceeding the natural injectivity of the formation, pumping out a liquid, carrying out preparatory discharges in the treated area, drilling reservoir wells from them, and extracting gas, in order to improve the coal seam , in the process of pumping out the working fluid, determine the flow rates of the water-gas mixture and, after stabilization of the water-gas emission, carry out the first preparatory generation in the humidification zone, from it to 25 both sides drill in reservoir degassing wells and carry out methane suction, and subsequent workings are carried out in an array degassed by surface and reservoir wells. 1500792 FIG. 2