SU1382980A1 - Method of degassing outburst-hazardous seams - Google Patents

Abstract

The invention relates to the mining industry and m. used in underground mining of gas-bearing and exhaust-hazardous formations. The purpose of the invention is to increase the efficiency of degassing and reduce its time by increasing the boundaries of the protective action of the discharge zone. The day of this drill is degassing wells to the reservoir prior to its unloading. Cased wells perforated pipes. When approaching the unloading zone to the protected zone for a distance in the projection on the horizontal plane of the bottom section of the protective formation at least 90 m, hydraulic fracturing is performed. The fracturing fluid is pumped out, as well as methane from the zone of high pressure rock. To improve the degassing efficiency when developing a contiguous reservoir along the strike, the distance from the downhole reservoir to the protective reservoir is calculated from the form factor, (h + m) ctS, where h is the thickness of the rocks between the layers, m; m — power of the degassed formation, m; - boundary angle of rocks displacement, from the strike side, rad. During the development of a protective stratum on an uprising, the distance a a is determined by the f-le a (h + t) to cos (+): sin Ud, where ce is the dip angle, rad; - the boundary angle of rocks displacement from the side of the uprising, I am glad, and when working downward, the distance is determined by the form f, a, (h + + m) .cos (ot) sinj, where / 5 is the boundary angle of rocks displacement from the side , glad. 3 hp f-ly, 4 ill. S (l

Description

The invention relates to the mining industry and can be used in the underground development of gas-bearing and outburst formations.

The aim of the invention is to increase the efficiency of degassing and reduce its time by increasing the boundaries of the protective action of the discharge zone.

FIG. 1 shows a scheme for implementing the method; in fig. 2-4 - schemes for determining the parameters of the advance of fracturing, plan.

The method is carried out as follows.

Initially, the protective layer 1 is worked out. The term protective refers to formations whose mining excludes the possibility of outliers, and also to formations that have a pressure-relieving effect from rock pressure, although the possibility of emissions is not completely excluded. On the seam 2 to be protected, the width of the zone that is promising for carrying out degassing is determined. For this purpose, the plan of the protected seam is projected onto the mining plan of the column on the protective seam being worked out and this contour is expanded to the width of the dynamic zone of the elevated mountain pressure, the value of which is in any case not less than 90 m and is determined as protective layer to the boundary of the protected zone.

When developing a contiguous reservoir along strike

a, (h + m) ctgS o, where h is the thickness of the rocks between the regions

m;

m - capacity of the degassed reservoir, m ;.

OQ - boundary angle of displacement

rocks from the strike strike glad.

When working out the protective layer of the uprising

 (h + m) cos () z1pu „

where d is the dip angle, glad;

Jfo is the boundary angle of rocks displacement from the side of the uprising,

glad.

When working out a protective layer in the fall

(h + m) cos (Pa- ob) sinfbo

but,

where PQ is the boundary angle of rocks displacement from the side of falling, rad.

These ratios are the advanced fracturing parameters in the planned projection and are shown as follows.

The formula for determining a ,, (FIG. 2) is derived from the right triangle ABC

AC a, (h + m) ctg5o.

The formula for determining a (Fig. 3) is derived as follows.

From the right triangle ABD, the side AB is determined.

RD

AB, BD h + t, 31pu „

so

AB

(h + w) sin Jo

The right side of the AC is determined from the right triangle ABC.

AC a, AV.eoz (| p „. O.) I L ± fi | iil L« L).

The formula for determining a (Fig. 4) is derived from the rectangular triangle ABD

AD

AB

sin | b,

; AD h + m.

so

AV). sin ro

From the triangle ABC, BC is defined as BC .a, LVCoCsr, -.). (B. (P.-ri

In advance, prior to the formation of a zone of elevated rock pressure (another approach at the reservoir), the wells are directed to the protected formation and positioned within the contour of the rock pressure zone defined by the ratios. The wells 4-8 are drawn either from the reservoir workings of the protected formation, or from the field workings 3, or from the workings of the protective formation, are cased with pipes and hydraulic fracturing is performed. The fracturing operations are carried out when approaching the intake at the protective formation to the boundary of the protected zone at a distance of a, a., Ao, 90 m.

The geomechanical basis of the method is as follows.

During the undermining of an array of rocks containing gas-bearing strata.

Claims (4)

1. Method of degassing outburst-hazardous formations, including unloading of a highly hazardous formation by working on a protective formation, drilling degassing wells to the formation, their connection to the gas pipeline and pumping methane from an outwardly hazardous reservoir, characterized in that, in order to increase the efficiency of degassing and reduce its duration by expanding the boundaries of the protective action of the unloading zone, the degassing wells drill onto the reservoir prior to its unloading, plant holes with perforated pipes and perform hydraulic fracturing at the approach of the unloading zone to the protected zone to the distance in the projection on the horizontal plane of the cross-section of the bottom of the protective formation not less than 90 m, the fracturing fluid is pumped out and However, methane is pumped out of the zone of subsurface rock pressure. 2. The method according to claim 1, which is based on the fact that, in order to increase the efficiency of degassing during the development of a contiguous reservoir along the strike, the distance from the barrier section of the protective formation to the boundary of the protected zone is determined from ratios a, (h + m) ctgS, where h is the thickness of the rocks between the layers, m; m — power of the degassed formation, m; Yd is the boundary angle of rocks displacement from the strike, rad. 3. The method according to claim 1, characterized in that, in order to increase the efficiency of degassing during the development of a protective stratum on an uprising, the distance from the site of the protective stratum to the boundary of the protected zone is determined from the ratio (h + m) cos (o-ob) 2 sinj " where is the dip angle, rad; Jg is the boundary angle of rock displacement from the uprising, rad. 4. The method according to claim 1, characterized in that, in order to improve the efficiency of degassing during the development of the protective formation in the fall, the distance from the bottom of the protective formation to the boundary of the protected zone is determined from the ratio az (h + m.) cos (Po - оС sin jb where the boundary angle of displacement of rocks from the side of the fall is rad. about 1382980  x y x yuu yyy xxx x x city / .2 u 2r Fig.Z Figm