RU2054557C1 - Method for degassing the coal seam - Google Patents

Method for degassing the coal seam Download PDF

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Publication number
RU2054557C1
RU2054557C1 RU92014146A RU92014146A RU2054557C1 RU 2054557 C1 RU2054557 C1 RU 2054557C1 RU 92014146 A RU92014146 A RU 92014146A RU 92014146 A RU92014146 A RU 92014146A RU 2054557 C1 RU2054557 C1 RU 2054557C1
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coal seam
coal
well
vertical
wells
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RU92014146A
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Russian (ru)
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RU92014146A (en
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Е.В. Крейнин
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Индивидуальное частное предприятие Научно-технический центр "Полигаз"
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Priority to RU92014146A priority Critical patent/RU2054557C1/en
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Abstract

FIELD: mining. SUBSTANCE: method for degassing the coal seam provides for coal seam degassing with the use of horizontal and inclined bore holes. Novelty consists in fire expansion of bore holes by countercurrent moving of fire seat. Technological conditions optimizing the process of employment of established collectors for methane recovery are offered. EFFECT: higher efficiency. 3 cl, 4 dwg

Description

 The invention relates to the degassing of coal seams, carried out with the aim of extracting and trapping the methane contained in them, providing, on the one hand, the safe operation of mines (explosions, emissions) and, on the other hand, the disposal of valuable hydrocarbon fuel.
 A known method of degassing a coal seam using various wells (inclined, horizontal, fan, etc.), passed both from workings and chambers, and from the surface [1] Such wells are equipped with a vacuum-suction system both immediately after drilling and after conducted through them hydraulic fracturing of the coal seam. However, the limited filtration surface of these artificial reservoirs causes small inflows of coal methane to them, and, consequently, long periods of required degassing. The last decision of the American company Enrot [2], which consists in securing hydraulic fractures in the process of their creation with the help of special solid aggregates (sand), on the one hand, is characterized by low controllability in the direction of the fracture gap and, on the other hand, by a limited influx of coal methane to them .
 The closest technical solution is to drill a vertically inclined well for degassing a coal seam at the A. Skochinsky mine [3] In this case, the inclined part of the well was drilled in the soil of the coal seam and hydraulic fractures along the coal seam were performed along its length. However, this known method also has a disadvantage due to the limited filtration surface, and therefore, the low influx of coal methane to it.
 The aim of the invention is to increase the efficiency of the process by increasing the flow of methane to artificial reservoirs with a high filtration surface.
 The goal is achieved by the fact that in the known method of degassing a coal seam, which consists in drilling directional and vertical wells from the surface, performing hydraulic fracturing of the coal seam through them and suctioning it after being filtered to the created artificial reservoirs of coal methane, a directional and vertical well drilled from the surface is connected between by the method of hydraulic fracturing of a coal seam, a coal seam is ignited in a vertical well with a closed drilled surface a well, then after the pressure drop in the vertical well, the blast is gradually transferred to the directional well, and the vertical is opened to divert the combustion products of the coal seam, then the hydraulic resistance of the horizontal coal channel is controlled during countercurrent movement of the combustion zone along it, the completion of which is fixed under the directional well column to establish the minimum value of hydraulic resistance of the coal channel under development.
 After completion of the development of the drilling coal channel, both wells are used to extract methane flowing to the walls of the thermally developed artificial reservoir. As the blast in the proposed method, air enriched with oxygen from 21 to 96% is used. For intensive cracking of the surface of a thermally worked-out collector, it is cooled by supply or running water. For greater coverage of the area of the coal seam being developed, the aforementioned directional wells drilled from the surface are connected to each other in various shapes.
 A comparative analysis of the proposed solution with the known shows that the claimed method is characterized in that the coal seam is degassed through thermally developed extended drilling channels with fractured walls and, due to this, a large coal methane filtration surface. Thus, the claimed method meets the criteria of the invention of "novelty."
 Known technical solutions [3] in which long drilling channels are used. However, the implementation through them only fracking does not allow to achieve a noticeable increase in the surface of artificial reservoirs. In the claimed technical solution, they achieve not only a qualitative, but also a noticeably quantitative effect in creating large methane filtration surfaces. This allows us to conclude that it meets the criterion of "significant differences". The heat treatment of coal drilling channels with appropriate control over its implementation provides an increased inflow of coal methane to them, and consequently, effective degassing of the coal field, as well as reducing its outburst hazard.
 In FIG. 1, 2 is a schematic diagram of a pair of wells, a cross section on a horizontal (Fig. 1) and inclined (Fig. 2) coal seam; figure 3 hydraulic characteristics of the process of heat treatment of a long drilling channel in a coal seam; in Fig.4 a possible system of modules shown in Fig.1, covering coal deposits in area (in the plane of the coal seam).
 The proposed method of degassing coal seams is implemented as follows.
 Directional wells 2 are drilled from the surface into a coal seam 1 to be degassed in a horizontal (Fig. 1) or inclined (Fig. 2) bed. Depending on the specific conditions, these wells may have vertical or inclined shafts. The uncased part 3 of these wells can be made horizontal (Fig. 1) or inclined. At the far ends of the directed wells 3, vertical or deviated wells 4 are drilled, which are cased by the column before entering the coal seam. Wells 4, as a rule, are connected to the drilling channel 3 by the method of hydraulic fracturing of a coal seam according to known and mastered technology. After washing the gap and the drilling channel with water, the coal seam in the bottom of the well 4 is fired up, while the well 2 is closed. Simultaneously with the pressure drop of the blast (air) at the head of the borehole 4, the blast is gradually transferred to the directed borehole 2, and the vertical borehole 4 is opened to divert the combustion products of coal. The burning center begins to move into the well 2 by blast.
In FIG. Figure 3 shows an example of the firing of a drilling coal channel carried out at a constant flow rate. In the process of developing a coal channel, the value of its hydraulic resistance is fixed
ΔP P 2 ΔP 2 ΔP 4 , where P 2 is the blast pressure at the wellhead 2;
ΔP 2 hydraulic resistance of the cased part of the well 2;
ΔP 4 hydraulic resistance of the well string 4.
 As the combustion zone moves along the channel 3 towards the blast, its hydraulic resistance naturally decreases, since the diameter of the worked channel 3 adjacent to the well 4 increases. As soon as the combustion zone moves under the directional well string 2, the hydraulic resistance ΔP stabilizes and becomes almost constant.
In practice, on a coal seam of the Kiselevsky deposit, a horizontal drilling channel with a diameter of 146 mm and a length of 120 m was thus worked out at an average flow rate of 1240 m 3 / h of air blast in 72 hours, while the average diameter of the developed channel became equal to 800 mm.
 Such an artificially created reservoir, the walls of which are streaked with numerous and deep cracks, is an effective drain for coal methane. Wells 2 and 4 can then be equipped to extract (suck) methane.
 As a blast during the fire development of the drilling channels and, if necessary, subsequent degassing of the coal seam to create large free volumes, air enriched with oxygen from 21 to 96% is used. The use of oxygen-enriched air favors the intensification of the fire development of the drilling channels, as well as their deeper heating walls, and therefore leads to longer cracks.
 Intensive cracking in the walls of the worked channel contributes to their active cooling. This is achieved by filling the combustion volume of the coal seam (well-developed drilling channels) with water. For this, both underground water and water pumped from the surface can be used. Subsequent purging of these volumes with air facilitates methane recovery. Peripheral flooding of the coal seam is useful, which favors the extrusion of methane into artificial reservoirs.
 The proposed method can be used not only for the degassing of a coal deposit (both preliminary and during mining of coal seams), but also for unloading certain sections of it, including preventing the danger of emissions. In this regard, the pairs of wells 2 and 4 shown in FIG. 3 can be combined into various figures. 4, one of such combinations is shown as an example. A specially developed technology for this combination will allow to thermally work out all the drilling channels 3.
 Using the proposed method for the degassing of a coal seam provides the following advantages compared to existing developments.
 The creation of an artificial reservoir with a large lateral filtration surface ensures the flow of methane and, consequently, the effective degassing of the coal seam.
The specific consumption of air blast for the fire expansion of the drilling channel in the coal seam is only 700-900 m 3 / pm. (pressure up to 5 bar).
 Effective degassing of the coal seam according to the proposed method is possible both through wells drilled from the surface, and through wells from underground workings.
 The task of colossal social significance is becoming realistically feasible to prevent methane explosions in mines.
 The opportunities for utilization of coal methane are significantly increasing.

Claims (3)

 1. METHOD OF DEGRASING COAL LAYER, which consists in drilling from the surface of directional and vertical wells, performing through them a hydraulic fracturing of the coal seam and suction after that filtered methane to artificial reservoirs, characterized in that the directional well drilled from the surface is connected through the coal seam and a vertical well between themselves by the method of hydraulic fracturing of a coal seam, a coal seam is ignited in the second of them with the first well closed, then after the pressure drop in a vertical well, the blast is gradually transferred to a directional well, and a vertical one is opened to divert the combustion products of the coal seam, then the hydraulic resistance of the drilling channel through the coal seam is controlled during countercurrent movement of the combustion center along it, the completion of which is recorded by stabilizing the hydraulic resistance of the channel being worked through the coal seam After that, both wells are used to extract methane flowing to the thermally developed reservoir.
 2. The method according to claim 1, characterized in that as the blast use air enriched to varying degrees with oxygen.
 3. The method according to claims 1 and 2, characterized in that the thermally developed collector is actively cooled by supply and running water.
RU92014146A 1992-12-24 1992-12-24 Method for degassing the coal seam RU2054557C1 (en)

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RU92014146A RU2054557C1 (en) 1992-12-24 1992-12-24 Method for degassing the coal seam

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RU92014146A RU92014146A (en) 1995-05-20
RU2054557C1 true RU2054557C1 (en) 1996-02-20

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2616635C1 (en) * 2013-10-16 2017-04-18 Чайна Юниверсити Оф Майнинг Энд Текнолоджи Method of improved combustible gas recovery using underground two-phase gas-liquid variable based on phases of unworked coal fracturing in coal mine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
1. Руководство по дегазации угольных шахт. М., 1990, с.186. 2. Контракт треста "Кузбассуглеразведка" с компанией "Енрот" (США), 1992. 3. Ярунин С.А., Лукаш А.С., Конарев В.В. Опыт проведения гидродинамического воздействия на углепородный массив через скважину с горизонтальным окончанием ствола. М.: Уголь, 1990, N 6, с.18-20. *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2616635C1 (en) * 2013-10-16 2017-04-18 Чайна Юниверсити Оф Майнинг Энд Текнолоджи Method of improved combustible gas recovery using underground two-phase gas-liquid variable based on phases of unworked coal fracturing in coal mine

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