SU1652620A1 - Method for degassing of coal-containing depth of worked- out area - Google Patents

Abstract

This invention relates to mining, and b. used to reduce the gas content of excavation areas of coal mines. The purpose of the invention is to increase the efficiency of degassing and prevent the accumulation of methane at the interface of lava with redeemable ventilation production. Auxiliary wells are drilled in the excavation area of the coal seam with a turn toward the goaf. Auxiliary wells are drilled to the intersection with gas recovery collectors. Drilling is performed prior to the beginning of the unloading of rocks. The auxiliary wells are isolated from the atmosphere of the mine workings, after which the gas suction wells are drilled to cross the auxiliary wells. The wells overlap in the zone of intense fracturing. In case of weak fracturing, the surrounding rocks are torpedoed. The drilled gas suction wells are sealed and connected to the local gas pipeline. Methane entering the gas suction and auxiliary wells is removed from the host rocks through the gas suction wells. 1 h. the item of f-ly, 4 ill. Yo

Description

The invention relates to the mining industry, mainly coal, and can be used to reduce the gas abundance of excavation sites, to control methane accumulations on the mains of vents with ventilation openings, and to improve the safety of mining operations on the gas factor by eliminating sudden gas breakthroughs into mining openings.

The purpose of the invention is to increase the efficiency of degassing and prevent the accumulation of methane at the interface of the lava with the absorbed ventilation production.

FIG. Figure 1 shows a schematic diagram of the location of the pipeline and wells in the lava along the strike of the formation; in fig. 2 shows section A-A in FIG. one; Fig. 3 shows the layout of a gas pipeline and a well in a lava along a dip; in fig. 4 shows a section BB in FIG. 3

The method of degassing the coal-bearing stratum and the space developed is carried out as follows.

In the area of the coal seam 1 (Fig. 1, 3), auxiliary wells are made from production 2 prior to the beginning of the unloading of the rocks.

ABOUT

ate

YU

about

YU

about

3 before they intersect the gas outlet collectors 4 (Fig. 2, 4). The drilled wells 3 are isolated from the working atmosphere. Then, suction wells 5 from the same production are carried out in groups (bushes) in such a way that they function in the zone of intense cracking in the host rocks 6. Wells 5 are connected to the degassing gas pipeline 7.

Auxiliary gas-conducting wells 3 are drilled from production 2 to additional layers (Fig. 1, 2) or over-developed (Figs. 3, 4), with a turn in the direction of the open space of the excavation section. The wells 3 are parallel to the intersection line of the unloading planes of the enclosing rocks, i.e. the planes formed on the boundary of the developed space along the ventilation openings and on the boundary of the developed space along the line of the clearing hole. The distance between the gas-conducting wells 3 is determined by calculation or is established empirically.

Gas extraction wells 5 (Figs. 1-4) are led from outlet 2 also with a turn towards the developed space of the excavation section. Wells 5 bur t bushes 2-3 in the bush. The distance between well pads is preferably chosen to be a multiple of the distance between gas transfer wells with overlapping projections on the generation axis of previous and subsequent gas extracting wells by less than 10-15 meters. During degassing of the subsurface gas wells, they are positioned above the formation in the zone crack formation.

One of the gas suction wells is located in the plane of discharge of the host rocks relative to the stationary boundary of the open space (along the ventilation workings), while others are located in the cracking zones in the vicinity of this plane, i.e. deflected by 2-3 degrees in the horizontal plane from the middle well in both directions. This improves the aerodynamic connection of the auxiliary well 3 with gas suction wells 5. The wells 5 are sealed and connected to the gas pipeline.

During the degassing of the overburden, the bottom of the wells 5 are located in the zone of formation of cracks under the reservoir 1, the gas suction and auxiliary wells prevent the accumulation of large volumes of methane in the overburden, and sudden gas breakthroughs do not occur.

If monolithic enclosing rocks are contained in the excavation site, which prevent unloading of the gas recovery collectors, the process of cracking in

these rocks are intensified, for example, by torpedoing.

Torpedoing is carried out through gassing wells 5 before the zone of unloading of rocks approaches to them by cleansing hole. An array is torpedoed along the entire active length of gas suction wells or opposite each of the cross or auxiliary wells 3. Experimentally determine the feasibility of using the torpedoing of all gas suction wells 5 in the bush or only the central one located in plane unloading of the enclosing rocks of a relatively fixed boundary of the developed space, followed by drilling in the bush of the gas suction wells adjacent to it.

The order of execution of the work and the parameters of the torpedoing of the wells are established in accordance with the known techniques for torpedoing the rock mass. In the event of the breakdown of the integrity of the gas-extracting burs during torpedoing, they are restored by repeated drilling.

In the course of cleaning operations, gas collectors are discharged from rock pressure. The methane released from the unloaded reservoirs located behind the zone of intensive resorption flows through the auxiliary wells 3 towards the clearing site. In the zone of influence of the clearing site, with intensive cracking between the intersecting

0 auxiliary 3 and gas-suction 5 wells form an aerodynamic connection. In the field of aerodynamic effects of rd-suction wells 5 methane flowing through auxiliary

5 wells 3 from gas outlet collectors are picked up by wells 5 and diverted to the gas pipeline 7.

PRI me R. Under the conditions of formation 1, worked out by long pillars along stretch with maturing the workings following the lava and having coalesced formations at 15 and 45 m, respectively, the degassing scheme according to FIG. 1. The angle of incidence is 7 °; the thickness of the immediate roof is 17 m; removable reservoir thickness 1.8 m; the discharge angle of underworked rocks is 65 °. Auxiliary wells were drilled from the ventilation output of the section parallel to the line of intersection of the planes pg

i ruses of mixing psrid, formed on the open spaces of the worked out space 1 T., of ventilation Ryrptkki and the cleaning of the clearing line.

Vion between the projections onto the horizontal plane of the pedal line of the reservoir and the line of intersection of the planes of discharge of the host rocks at the boundaries of the developed space is determined from the expression

 cos (V - ") cos v

where V is the discharge angle of the worked rocks, measured from the bedding plane, degree;

a- gog dip, degree,

whence the hijacking r 1 is 39e.

The angle between the line of intersection of the planes times. The races of the host rocks on the border of the developed space and its projection on the horizontal plane are determined from the expression

tg tg (V -) cos,

from where angle fi 51 °.

The length of the auxiliary wells SLE was calculated by the formula M sin (if) - ")

sin 1 / si

where M is the distance up to the remote distant reservoir that discharges gas into the developed space of the site, m.

The length of the asp from the gas wells 3 g.– from the gavil 54 m. The angle of inclination of the gas suction wells to the horizon / 2 was determined by the formula

- LD +) sin (y-a)

1sqv2 Sin C)

where h is the power of the immediate roof, m;

 discharge angle of underworked rocks, measured from the bedding plane, degree;

a - dip angle, degree;

skch2 - well length, m

With h 17 m; 65 °; y-7 °; 1C-100 m; the angle of inclination of the wells to the horizon is 14 °.

The turning angles of the gas extraction wells, measured in the horizontal plane between the projections of the wells and the dip line, are determined as follows. The rotation angle of the average well in the bush is calculated using the formula (hi -iL8) cos () 1Скв2 sin

ICKHI

C0) 2

Vron if) 2 is R1 °. The turning angles of the side gas-absorption wells are 73 and 84 °.

Thus, for auxiliary wells, 3 horizontal reversals were G9 °. angle of inclination to horizontal- 30HTV 51 °, well length 54 m: distance between the saws, determined from experimental data 15 m. For gas suction wells 5, the turning angles were 78, 81 and 84 °, the inclination to the horizon was 14 °, the length of the wells 100 m; the distance between the bushes of the skva.kin 60 m. The vacuum at the mouths of gas suction wells mm Hg. G.S.Z. drilling of auxiliary wells their Ustya were geometized.

3 During the process of conducting sewage treatment works for geysers, the collectors were unloaded from the mountain pressure. Methane, released from the adjacent layers and host rocks, flowed through the auxiliary wells towards the clearing site. In the field of aerodynamic effects of gas suction wells 5, methane entering the wellbore 3 was caught by skzhazhinami 5 and it was diverted to the degassing gas pipeline 7.

Claims (2)

1.Sposib of degassing of the coal-bearing stratum and of the open space, including drilling of suction wells with a turn in the direction of the developed space of the lava, their sealing, connection to the drainage gas pipeline and suction of gas, characterized in that to increase the efficiency of degassing and prevent methane accumulations at the interface of the pavas with redeemable ventilation generation, until the discharge of the coal-bearing unit is additionally drilled auxiliary wells until they cross the gas return collectors, isolate the auxiliary wells from the production atmosphere, and the gas-suction wells drill crosswise to the subsidiary wells, by this Methane entering all wells is removed through gas suction wells. 2. A method according to claim 1, characterized in that, in order to improve the aerodynamic coupling between the gas suction and auxiliary wells in areas including monolithic enclosing rocks intensify the process of cracking by torpedoing enclosing rocks. Fig l Aa FIG. 2 Editor S. Lisin FIG. C Compiled by I. Fed eva Tehred M. Morgentalkorrektor And, Muska