CN107313803B - Underground combustion space area volume determination and filling method - Google Patents
Underground combustion space area volume determination and filling method Download PDFInfo
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- CN107313803B CN107313803B CN201710462088.2A CN201710462088A CN107313803B CN 107313803 B CN107313803 B CN 107313803B CN 201710462088 A CN201710462088 A CN 201710462088A CN 107313803 B CN107313803 B CN 107313803B
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 30
- 239000000700 radioactive tracer Substances 0.000 claims abstract description 30
- 238000002309 gasification Methods 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 8
- 239000003245 coal Substances 0.000 claims description 26
- 239000002002 slurry Substances 0.000 claims description 10
- 239000004568 cement Substances 0.000 claims description 6
- 239000011440 grout Substances 0.000 claims description 4
- 238000012544 monitoring process Methods 0.000 claims description 4
- 239000004927 clay Substances 0.000 claims description 3
- 239000002131 composite material Substances 0.000 claims description 3
- 239000010881 fly ash Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 230000002285 radioactive effect Effects 0.000 claims description 3
- 239000003034 coal gas Substances 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims 1
- 230000015572 biosynthetic process Effects 0.000 abstract description 2
- 238000005259 measurement Methods 0.000 abstract description 2
- 239000011435 rock Substances 0.000 description 5
- 238000005065 mining Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 239000010883 coal ash Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000002956 ash Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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Abstract
The invention provides a method for determining and filling the volume of an underground combustion space area, which is characterized by comprising the following steps: step S1, collecting and detecting the background value of the gas in the underground gasification area after the gasification is finished; step S2, introducing tracer gas into a certain gas inlet hole, and then collecting and detecting gas components in other gas outlet holes; step S3, calculating the volume of the underground combustion space area; step S4, comparing the volume of the combustion space area obtained by measurement and calculation with the value obtained by conventional calculation, and if the volume exceeds a certain scale or according to requirements, performing step S5; and step S5, exhausting the air outlet to form negative pressure, grouting the air inlet, and quantitatively filling. The method can directly measure and calculate the volume of the underground combustion space area, and has the advantages of simple operation, easy calculation and low cost. The volume of the burned-out area calculated conventionally without consideration of formation expandability can be verified. On the premise of knowing the scale of the combustion space area, the combustion space area which needs to be filled or needs to be filled is filled under negative pressure, so that the complete closed filling of the underground combustion space area is realized while the quantity and the cost of filling materials are conveniently controlled.
Description
Technical Field
The invention belongs to the technical field of underground coal gasification and mining, and relates to a method for determining the size of an underground combustion space area and filling the underground combustion space area.
Background
Underground coal gasification is a chemical coal mining method for converting coal into combustible gas in situ by controlled combustion of underground coal. Compared with the traditional underground mining, the method has the advantages that the coal face does not need to be manually entered in the production process, various roadways and related chambers do not need to be constructed underground, only geological drilling is needed to be constructed, and the available components in the coal resources can be discharged to the ground surface in a mixed gas mode after the coal bed is ignited by inputting the gasifying agent. Underground coal gasification has the advantages of improving the utilization rate of coal resources, reducing the labor intensity of workers, greatly reducing environmental destruction and atmospheric pollution and the like.
The coal resources form a combustion space area after being gasified, the coal pillars are isolated and protected through reasonable arrangement, large-area settlement or collapse of the ground surface can be avoided, however, stress adjustment and instability of overlying strata of the combustion space area cannot be avoided, certain degree of collapse, crack and deformation are generated, sometimes, the change of ground surface subsidence is a slow mantle process, and if manual facilities such as buildings, roads and the like are constructed on the ground surface after a plurality of years, the loss of life and property of the ground surface caused by the existence of the underground combustion space area is not eliminated. Meanwhile, if multiple layers of coal resources exist in the stratum, the burning space area formed after one layer of gasification affects the exploitation of the adjacent layer of the stratum, and resource waste is caused to a certain extent. Therefore, after the coal resources are gasified and useful components are mined, the size of the underground combustion space area needs to be accurately mastered, and the underground combustion space area needs to be reasonably filled by adopting a specific method according to the scale of the cavity of the combustion space area, so that the subsequent stratum collapse is avoided, the utilization rate of multi-layer coal resources is improved, and the stratum stress distribution is restored to a balanced state while the coal resources are cleanly utilized.
Disclosure of Invention
In view of the above, the present invention provides a method for determining and filling the volume of an underground combustion space area, which aims to solve the above problems.
The invention provides a method for determining and filling the volume of an underground combustion space area, which is characterized by comprising the step S1 of collecting and detecting a gas background value of an underground gasification area after gasification is finished;
step S2, introducing tracer gas into a certain gas inlet hole, and then collecting and detecting gas components in other gas outlet holes;
step S3, calculating the volume of the underground combustion space area;
step S4, comparing the volume of the combustion space area obtained by measurement and calculation with the value obtained by conventional calculation, and if the volume exceeds a certain scale or according to requirements, performing step S5;
and step S5, exhausting the air outlet to form negative pressure, grouting the air inlet, and quantitatively filling.
Further, in the method for determining and filling the volume of the underground combustion empty area, in step S1, the air intake of each air intake hole is stopped, and when the air outlet pressure does not exist at the opening of each air outlet hole, the background value of the underground gas is collected and detected.
Further, in the method for determining and filling the volume of the underground combustion empty area, the method is characterized in that step S2, a tracer gas releasing device is connected to the orifice of the gas inlet hole, a tracer gas collecting device is connected to the gas outlet hole, a radioactive isotope tracer gas or a stable isotope tracer gas is injected into the gas inlet hole by adopting a pulse releasing method, and a gas tracer is injected into the gas inlet hole by 300cm3Injecting at a speed of/min to enable the concentration of the injected tracer in the coal bed gas to reach 150 mg/L.
Further, in the underground combustion space area volume determining and filling method, the method is characterized in that in step S5, an air draft facility is installed at the opening of the air outlet.
Further, in the method for determining and filling the volume of the underground combustion space area, the method is characterized in that in step S5, the grouting material is CL-C type clay cement slurry, cement fly ash slurry, paste-like slurry or double-liquid composite grouting material.
Further, in the method for determining and filling the volume of the underground gob, the method is characterized in that in step S4, when the measured volume of the gob is larger than 1/3 of the calculated volume of the coal-fired quantity and the mixed gas component, the gob is filled.
Further, in the method for determining and filling the volume of the underground combustion space area, the method is characterized in that in step S3, the gamma logging instrument or the gamma spectrometer is used for monitoring the gas outlet, and the concentration t of the tracer gas appears1Then, the concentration of 2-3 peaks is continuously monitored until t2When the time is calculated,
in the formula:
m: total mass of injected gas;
M1：t1to t2Mass of gas discharged over a period of time;
C(t2)：t2the gas concentration at the moment;
Vburning device: the volume of the combustion space area.
The invention has the beneficial effects that:
the volume of the underground combustion space area can be directly measured and calculated, the operation is simple, the calculation is easy, the cost is low, and the volume of the combustion space area calculated by conventional calculation without considering rock formation expansibility can be verified.
On the premise of knowing the scale of the combustion space area, the combustion space area which needs to be filled or needs to be filled is filled under negative pressure, so that the complete closed filling of the underground combustion space area is realized while the quantity and the cost of filling materials are conveniently controlled.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a schematic view of the injection of trace gas according to the present invention
FIG. 2 is a schematic view of the goaf filling of the present invention
1-air inlet hole, 2-air outlet hole, 3-stratum bending zone, 4-stratum fracture zone, 5-combustion empty zone, 6-falling rock and coal ash, 7-tracer gas releasing device, 8-tracer gas collecting device, 9-grouting facility and grout, and 10-air draft facility
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
According to the invention, after underground coal resources are gasified, air inlet of each air inlet hole is stopped, when the hole opening of each air outlet hole basically has no air outlet pressure, a gas background value of an underground gasification area is collected and detected, then the stability of some tracer gas is utilized, the tracer gas is introduced into a certain air inlet hole, then gas components are collected and detected in other air outlet holes, and the volume size of the underground combustion area is obtained through calculation processing. Considering the expansibility of the top floor rock stratum after being heated and the quantity of the residual ash after different coal beds are combusted, when the volume of the combustion space area obtained by calculation is larger than 1/3 of the volume calculated by the quantity of the coal and the components of the mixed coal gas, the underground combustion space area is filled by adopting the original air inlet hole for grouting and the original air outlet hole for exhausting air to form negative pressure. The invention is suitable for detecting and filling the volume of the underground coal gasification combustion space area.
After the coal resource is gasified, an underground combustion empty area 5 is formed, the bottom of the underground combustion empty area is covered by the falling rocks and the coal ash 6, and the top rock stratum of the underground combustion empty area is sequentially distributed with a fracture zone 4 and a bending zone 3.
And (4) stopping air inflow of each air inlet hole, and collecting and detecting the background value of the underground gas when the hole opening of each air outlet hole has no air outlet pressure.
The vent hole 1 of the air inlet hole is connected with a tracer gas release device 7, the vent hole 2 is connected with a tracer gas collecting device 8, the air inlet hole is injected with radioactive isotope tracer gas or stable isotope tracer gas by adopting a pulse release method, and the gas tracer is injected by 300cm3Injecting at a speed of about/min to make the concentration of the injected tracer in the coal bed gas reach about 150 mg/L.
Monitoring gas outlet by using related equipment such as a gamma logging instrument or a gamma energy spectrometer, and continuously monitoring 2-3 peak concentrations to t when the concentration t1 of the tracer gas occurs2According to the law of conservation of mass, the mass of the injected tracer gas is equal to t1To t2Mass of tracer gas discharged in time period and t2The sum of the trace gas quality in the time-of-day burnt-out area is as follows:
M＝M1+C(t2)Vburning device
In the formula:
m: total mass of injected gas;
M1：t1to t2Mass of gas discharged over a period of time;
C(t2)：t2the gas concentration at the moment;
Vburning device: the volume of the combustion space area.
Then:
when the volume of the combustion space area obtained by calculation is larger than 1/3 of the volume calculated by the coal combustion amount and the mixed gas component, or according to the production requirement, the combustion space area is filled by adopting the following method.
And a grouting facility is arranged at the air inlet, grout 9 is injected into the grout, and an air draft facility 10 is arranged at the orifice of the air outlet, so that negative pressure is formed in the underground dead zone, and the filling of the fractured zone is facilitated.
The grouting material can be CL-C type clay cement slurry or cement fly ash slurry with low cost, or paste slurry, paste-like slurry and double-liquid composite grouting material according to local resources.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (4)
1. A method for determining and filling the volume of an underground combustion space area is characterized by comprising the following steps:
step S1, collecting and detecting the background value of the gas in the underground gasification area after the gasification is finished;
step S2, introducing tracer gas into a certain gas inlet hole, and then collecting and detecting gas components in other gas outlet holes;
step S3, calculating the volume of the underground combustion space area; performing gas outlet monitoring by using a gamma logging instrument or a gamma energy spectrometer, and when the concentration of the tracer gas is t1, continuing to monitor 2-3 peak concentrations until t2 and calculating
In the formula:
m: total mass of injected gas;
M1: mass of gas discharged during the time period t1 to t 2;
c (t 2): gas concentration at time t 2;
Vburning device: the volume of the combustion space area;
step S4, when the volume of the burning space area calculated by the calculation is larger than 1/3 of the volume calculated by the coal burning quantity and the mixed coal gas component, or according to the production requirement, the step S5 is carried out;
and step S5, installing a grouting facility at the air inlet hole to inject grout, and installing an air draft facility at the orifice of the air outlet hole to form negative pressure in the underground dead zone, so that the filling of the fractured zone is facilitated.
2. The underground combustion space area volume determining and filling method as claimed in claim 1, wherein in step S1, the air intake of each air intake hole is stopped, and the background value of underground gas is collected and detected when there is no air outlet pressure at the opening of each air outlet hole.
3. The underground combustion-empty area volume determination and filling method as claimed in claim 1, wherein step S2 is performed by connecting a tracer gas releasing device to an opening of the gas inlet hole, connecting a tracer gas collecting device to the gas outlet hole, injecting a radioactive isotope tracer gas or a stable isotope tracer gas into the gas inlet hole by a pulse releasing method, and injecting a gas tracer gas in an amount of 300cm3Injecting at a speed of/min to enable the concentration of the injected tracer in the coal bed gas to reach 150 mg/L.
4. The underground combustion-empty area volume determining and filling method as claimed in claim 1, wherein in step S5, the grouting material is selected from CL-C type clay cement slurry, cement fly ash slurry, paste-like slurry or double-fluid composite grouting material.
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| CN201710462088.2A CN107313803B (en) | 2017-06-16 | 2017-06-16 | Underground combustion space area volume determination and filling method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| SU924412A2 (en) * | 1980-10-01 | 1982-04-30 | Всесоюзный научно-исследовательский институт золота и редких металлов | Method for filling worked space |
| US4968187A (en) * | 1988-03-01 | 1990-11-06 | Mackenzie Burnett | System for backfilling a subterranean void |
| CN102607663B (en) * | 2011-11-30 | 2014-09-24 | 新奥气化采煤有限公司 | Underground cavity volume detection method and underground cavity volume detection device |
| CN104514577B (en) * | 2014-12-12 | 2016-04-20 | 中国矿业大学 | The method of coal seam large area spontaneous combustion in goaf is hidden in a kind of efficient improvement shallow embedding |
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