CN112901120A - Coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method - Google Patents
Coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method Download PDFInfo
- Publication number
- CN112901120A CN112901120A CN202110337765.4A CN202110337765A CN112901120A CN 112901120 A CN112901120 A CN 112901120A CN 202110337765 A CN202110337765 A CN 202110337765A CN 112901120 A CN112901120 A CN 112901120A
- Authority
- CN
- China
- Prior art keywords
- gas
- coal bed
- negative pressure
- coal
- well
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000003245 coal Substances 0.000 title claims abstract description 225
- 238000002347 injection Methods 0.000 title claims abstract description 66
- 239000007924 injection Substances 0.000 title claims abstract description 66
- 238000000605 extraction Methods 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 117
- 238000004519 manufacturing process Methods 0.000 claims abstract description 58
- 238000002156 mixing Methods 0.000 claims description 49
- 238000003860 storage Methods 0.000 claims description 30
- 239000007788 liquid Substances 0.000 claims description 7
- 239000011148 porous material Substances 0.000 claims description 6
- 230000009467 reduction Effects 0.000 claims description 4
- 239000000284 extract Substances 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims 1
- 230000009471 action Effects 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 263
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 30
- 238000003795 desorption Methods 0.000 description 16
- 230000000694 effects Effects 0.000 description 10
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 230000005012 migration Effects 0.000 description 6
- 238000013508 migration Methods 0.000 description 6
- 238000012546 transfer Methods 0.000 description 6
- 239000012530 fluid Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000002708 enhancing effect Effects 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- 239000013543 active substance Substances 0.000 description 1
- 239000002734 clay mineral Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 230000000638 stimulation Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/006—Production of coal-bed methane
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/166—Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium
- E21B43/168—Injecting a gaseous medium
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/30—Specific pattern of wells, e.g. optimising the spacing of wells
- E21B43/305—Specific pattern of wells, e.g. optimising the spacing of wells comprising at least one inclined or horizontal well
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/34—Arrangements for separating materials produced by the well
Landscapes
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
Abstract
The invention discloses a coal bed gas U-shaped well gas injection circulating negative pressure extraction device and a method, wherein the system comprises a negative pressure extraction system, a gas injection pipe arranged in a horizontal well and a circulating gas supply system used for communicating the negative pressure extraction system and the gas injection pipe; the circulating gas supply system converts the underground water pumped out from the negative pressure extraction system into high-temperature steam, and then the high-temperature steam is mixed with a small part of coal bed gas pumped out from the negative pressure extraction system, pressurized and supplied to a coal reservoir through a gas injection pipe; the method comprises the following steps: firstly, constructing a U-shaped well and a coal bed gas U-shaped well gas injection circulation negative pressure extraction device; secondly, depressurizing and extracting coal bed gas; and thirdly, extracting the coal bed gas under negative pressure. According to the invention, the mixed gas of the coal bed gas and the high-temperature steam produced by the coal reservoir is injected into the coal reservoir, and the ground negative pressure extraction is combined, so that the gas production efficiency is improved under the combined action of the three aspects, and the popularization and the use are convenient.
Description
Technical Field
The invention belongs to the technical field of coal bed gas exploitation, and particularly relates to a coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method.
Background
Coal bed gas is an unconventional clean and efficient energy source, and at present, coal bed gas in China has certain technical breakthrough and commercial development in different areas. But compared with the countries such as the United states, Australia and the like, the number of coal bed gas wells in China is large, but the total gas production amount is low, and particularly the gas production efficiency of a single well is low. The main reasons for the problems are that the existing ground coal bed methane development technology in China has low matching degree and poor adaptability with reservoir characteristics such as low pressure, low permeability and the like, and the gas production capacity of the coal reservoir cannot be stimulated.
At present, the exploitation mode of the ground coal bed gas in China mainly adopts a traditional operation system of 'drainage-depressurization-gas production' and injects CO into a coal reservoir through fracturing fluid2、N2And chemical active agents and the like enhance the permeability and wettability of the reservoir, but the injection of the fluids greatly destroys the original physical properties of the coal reservoir and seriously affects the recovery ratio of the coal bed gas. Through the field drainage and mining of the ground coal bed gas well, once the drainage quantity is reduced, namely when the liquid level of a shaft is reduced to be lower than a coal bed, the drainage and pressure reduction capacity of a screw pump is basically disabled, and the gas production rate is reduced immediately, so that the problems seriously restrict the development of the coal bed gas industry in China.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a coal bed gas U-shaped well gas injection circulation negative pressure extraction device, aiming at the defects in the prior art, the mixed gas of the coal bed gas and high-temperature water vapor produced by a coal reservoir is injected into the coal reservoir, and the ground negative pressure extraction is combined, so that the gas production efficiency is improved under the combined action of three aspects, wherein the coal bed gas injected into the coal reservoir enhances the coal-water contact area by utilizing the wall attachment effect of fluid, and the high temperature and high pressure generated by the collapse of bubbles stimulate the desorption of the coal bed gas adsorbed in the coal bed; injecting high-temperature steam to improve the temperature of the coal reservoir through heat carried by the steam, thereby enhancing the desorption rate of the coal bed gas; the negative pressure extraction can excite the water state in the coal matrix to change, combine the water to convert into free water, and promote the cavitation mass transfer, thereby improving the desorption and migration of the adsorbed gas in the coal reservoir, and the device has novel and reasonable design and is convenient to popularize and use.
In order to solve the technical problems, the invention adopts the technical scheme that: the utility model provides a coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device, U type well includes engineering well, production well and the horizontal well that communicates engineering well and production well, and the horizontal well is arranged in coal reservoir, its characterized in that: the system comprises a negative pressure extraction system arranged at the wellhead of a production well, a gas injection pipe arranged in a horizontal well and a circulating gas supply system used for communicating the negative pressure extraction system and the gas injection pipe;
the circulating gas supply system converts the underground water pumped out from the negative pressure extraction system into high-temperature steam, and then the high-temperature steam is mixed with a small part of coal bed gas pumped out from the negative pressure extraction system, pressurized and supplied to the coal reservoir through a gas injection pipe, so that gas adsorbed on the surface of coal in pores of the coal reservoir is desorbed.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: the negative pressure extraction system comprises a water pump extending into the production well, a negative pressure pump arranged at the wellhead of the production well and a gas-water separator communicated with the outlet of the negative pressure pump, a three-way pipe is arranged between the negative pressure pump and the wellhead of the production well, a first pipeline of the three-way pipe is communicated with the production well, a second pipeline of the three-way pipe is communicated with the extraction opening of the negative pressure pump, a third pipeline of the three-way pipe is communicated with the gas-water separator,
the circulation gas supply system includes the tank, the gas mixing box, a first air supply line for connecting gas mixing box and tank, and be used for connecting the second air supply line of gas mixing box and deareator's gas vent, communicate through the mixed gas pipeline between gas mixing box and the gas injection pipe, be provided with high temperature steam generator on the first air supply line and set up the first check valve between high temperature steam generator and gas mixing box, be provided with the second check valve on the second air supply line, the mixed gas pipeline has set gradually the booster pump on the road, pressure gauge and third check valve, the booster pump is close to the gas mixing box and lays, deareator's outlet and tank are connected.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: the exhaust port of the gas-water separator is divided into two paths, one path is communicated with the gas mixing box, and the other path is connected with the gas storage device.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: and a plurality of gas injection ports are formed in the pipe section of the gas injection pipe extending into the horizontal well.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: the temperature of the steam output by the high-temperature steam generator is 80-100 ℃.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: the mixed gas in the gas mixing box is prepared from the following mixed gases in a volume ratio of (90-95): (5-10) high-temperature steam and coal bed gas.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: the gas pressure in the mixed gas pipeline after being pressurized by the booster pump is 1.3-1.7 Pc, wherein Pc is the bottom flowing pressure of the horizontal well.
Foretell coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device which characterized in that: and the water outlet end of the water suction pump is connected with the water storage tank.
Meanwhile, the invention also discloses a method for improving the extraction rate of the coal bed gas by the circulating negative pressure extraction of the coal bed gas, which has simple steps and reasonable design, and is characterized by comprising the following steps:
constructing a U-shaped well and a coal bed gas U-shaped well gas injection circulating negative pressure extraction device;
step two, depressurizing and extracting coal bed gas:
step 201, a water pump is started, the water pump pumps water from a U-shaped well into a water storage tank, the liquid level in a production well is lowered, the pressure of a coal reservoir is lowered, and a production well starts to produce gas;
step 202, separating coal bed gas and water from the gas produced by the production well through a gas-water separator, enabling the separated water to enter a water storage tank, and enabling the separated coal bed gas to enter gas storage equipment;
step 203, after the flow rate of the coal bed gas separated in the gas-water separator is stable, opening a first one-way valve, a second one-way valve, a third one-way valve and a high-temperature steam generator, wherein the high-temperature steam generator extracts water in a water storage tank and outputs high-temperature steam to a gas mixing box, one part of the coal bed gas separated by the gas-water separator enters the gas mixing box, and the other part of the coal bed gas enters gas storage equipment;
the gas proportion in the gas mixing box is adjusted by adjusting the opening degrees of the first check valve and the second check valve, and the mixed gas in the gas mixing box is prepared from the following components in percentage by volume (90-95): (5-10) high-temperature steam and coal bed gas;
step 204, pressurizing the mixed gas in the gas mixing box by a booster pump, injecting the pressurized mixed gas into a coal reservoir through a gas injection pipe, desorbing the gas adsorbed on the surface of the coal in pores of the coal reservoir, separating coal bed gas and water from the gas produced by the production well through a gas-water separator again, pressurizing one part of the separated coal bed gas into the gas mixing box again together with the high-temperature water vapor, injecting the other part of the separated coal bed gas into a coal reservoir, and realizing the circular extraction of the coal bed gas;
step three, extracting coal bed gas under negative pressure:
when the liquid level in the U-shaped well is lowered to the coal seam roof, the water drainage and pressure reduction capacity of the water suction pump is disabled, the negative pressure pump is started at the moment, the pressure in the U-shaped well is reduced, the first one-way valve, the second one-way valve, the third one-way valve and the high-temperature steam generator are kept opened, and the coal seam gas is collected continuously until the coal seam gas extraction operation is finished.
Compared with the prior art, the invention has the following advantages:
1. the invention adopts the coal bed gas, namely the methane is mixed with the high-temperature steam, compared with nitrogen, the methane has better heat-conducting property, can be burst after the coal reservoir attaches to the wall, instantly generates high temperature and vibration, stimulates the desorption of the coal bed gas and improves the yield.
2. According to the invention, the demand of the coal bed gas mixed with the high-temperature steam is small, and the desorption rate of the coal bed gas can be improved by mixing a small amount of methane gas with the high-temperature steam.
3. The method makes full use of and plays the role of a gas injection channel of the engineering well, the injected gas is the mixed gas of the coal bed gas and the water vapor of the coal reservoir, so that the coal reservoir is not polluted in the extraction process of the coal bed gas, the cyclic extraction of the coal bed gas is realized, the problem that the coal powder is easy to bury a water pump is solved, and the extraction efficiency of the coal bed gas is greatly improved under the condition of protecting equipment.
4. The method adopted by the invention has simple steps, is convenient for ground monitoring and is convenient to operate.
In conclusion, the design is novel and reasonable, the mixed gas of the coal bed gas and the high-temperature steam produced by the coal reservoir is injected into the coal reservoir, and the gas production efficiency is improved under the combined action of the three aspects of negative pressure extraction on the ground, wherein the coal bed gas injected into the coal reservoir utilizes the wall attaching effect of the fluid to enhance the coal-water contact area, and the high temperature and high pressure generated by the collapse of the bubbles stimulate the desorption of the coal bed gas adsorbed in the coal bed; injecting high-temperature steam to improve the temperature of the coal reservoir through heat carried by the steam, thereby enhancing the desorption rate of the coal bed gas; the negative pressure extraction can excite the water state in the coal matrix to change, combine the water to convert into free water, and promote the cavitation mass transfer, thereby improving the desorption and migration of the adsorbed gas in the coal reservoir, and being convenient for popularization and use.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
Fig. 1 is a schematic structural diagram of a coal bed methane U-shaped well gas injection circulation negative pressure extraction device adopted by the invention.
Description of reference numerals:
1-engineering well; 2-a production well; 3, a water pump;
4, a water storage tank; 5-a negative pressure pump; 6-high temperature steam generator;
7-gas-water separator; 8-a first one-way valve; 9-gas storage equipment;
10-a second one-way valve; 11-gas mixing box; 12-a booster pump;
13-a pressure gauge; 14-a third one-way valve; 15-a gas injection pipe;
16-gas injection port; 17-a three-way pipe; 18-horizontal well;
19-a first gas supply line; 20-a second gas supply line; 21-mixed gas line.
Detailed Description
As shown in fig. 1, the coal bed gas U-shaped well gas injection circulation negative pressure extraction device provided by the invention comprises an engineering well 1, a production well 2 and a horizontal well 18 for communicating the engineering well 1 with the production well 2, wherein the horizontal well 18 is positioned in a coal reservoir and comprises a negative pressure extraction system arranged at the well mouth of the production well 2, a gas injection pipe 15 arranged in the horizontal well 18 and a circulation gas supply system for communicating the negative pressure extraction system with the gas injection pipe 15;
the circulating gas supply system converts the underground water pumped out from the negative pressure extraction system into high-temperature steam, and then the high-temperature steam is mixed with a small part of coal bed gas pumped out from the negative pressure extraction system, pressurized and supplied to the coal reservoir through the gas injection pipe 15, so that the gas adsorbed on the surface of the coal in the pores of the coal reservoir is desorbed.
The invention adopts the coal bed gas, namely the methane is mixed with the high-temperature steam, compared with nitrogen, the methane has better heat conductivity, can be collapsed after the coal reservoir attaches to the wall, generates high temperature and vibration instantly, stimulates the desorption of the coal bed gas and improves the yield.
The coal bed gas mixed with the high-temperature steam is low in demand, and the desorption rate of the coal bed gas can be improved by mixing a small amount of methane gas with the high-temperature steam;
the mixed gas of the coal bed gas and the high-temperature steam produced by the coal reservoir is injected into the coal reservoir, and the gas production efficiency is improved under the combined action of the three aspects of extraction by combining with the ground negative pressure, wherein the coal bed gas injected into the coal reservoir utilizes the wall attachment effect of the fluid to enhance the coal-water contact area, and the high temperature and high pressure generated by the collapse of the bubbles stimulate the desorption of the coal bed gas adsorbed in the coal bed; injecting high-temperature steam to improve the temperature of the coal reservoir through heat carried by the steam, thereby enhancing the desorption rate of the coal bed gas; the negative pressure extraction can excite the state of water in the coal matrix to change, combine water to convert into free water and promote cavitation mass transfer, thereby improving the desorption and migration of adsorbed gas in a coal reservoir;
it should be noted that the invention fully utilizes and exerts the gas injection channel function of the engineering well 1, the injected gas is the mixed gas of the coal bed gas and the water vapor of the coal reservoir, so that no pollution is generated to the coal reservoir in the extraction process of the coal bed gas, the circular extraction of the coal bed gas is realized, meanwhile, the problem that the coal powder is easy to bury the water pump 3 is solved, and the extraction efficiency of the coal bed gas is greatly improved under the condition of protecting equipment;
compared with the prior art, the method has the advantages that additional preparation and separation of gas with high thermal conductivity, such as nitrogen, helium and the like, are not needed, incomplete separation of produced coal bed gas from other gas is avoided, production procedures are simplified, and production efficiency is improved.
In the embodiment, the negative pressure extraction system comprises a water suction pump 3 extending into a production well 2, a negative pressure pump 5 arranged at the well mouth of the production well 2 and a gas-water separator 7 communicated with the outlet of the negative pressure pump 5, a three-way pipe 17 is arranged between the negative pressure pump 5 and the well mouth of the production well 2, a first pipeline of the three-way pipe 17 is communicated with the production well 2, a second pipeline of the three-way pipe 17 is communicated with the air suction port of the negative pressure pump 5, a third pipeline of the three-way pipe 17 is communicated with the gas-water separator 7,
circulation gas supply system includes tank 4, gas mixing box 11, a first air supply line 19 for connecting gas mixing box 11 and tank 4, and be used for connecting gas mixing box 11 and gas water separator 7's gas vent, communicate through gas mixing pipe 21 between gas mixing box 11 and the gas injection pipe 15, be provided with high temperature steam generator 6 on the first air supply line 19 and set up the first check valve 8 between high temperature steam generator 6 and gas mixing box 11, be provided with second check valve 10 on the second air supply line 20, the booster pump 12 has set gradually on the gas mixing pipe 21, pressure gauge 13 and third check valve 14, booster pump 12 is close to gas mixing box 11 and lays, gas water separator 7's outlet and tank 4 are connected.
In this embodiment, the water pump 3 is a screw pump.
It should be noted that, after the coal bed gas mixed with the high-temperature steam and injected into the coal reservoir is acted on the coal reservoir, the coal bed gas enters the gas-water separator 7 through the production well 2 to be redistributed, no gas leakage exists in the whole process, no pollution is caused to the environment, meanwhile, the production safety is ensured, and the using effect is good.
In this embodiment, the exhaust port of the gas-water separator 7 is divided into two paths, one path is communicated with the gas mixing tank 11, and the other path is connected with the gas storage device 9.
In this embodiment, the second check valve 10 on the second gas supply line 20 is used to control the amount of the coal bed gas passing through the two channels at the gas outlet of the gas-water separator 7, and the opening of the second check valve 10 is adjusted to make the amount of the coal bed gas output by the second gas supply line 20 reach the value according to the amount of the coal bed gas needed by the mixed gas in the gas mixing tank 11.
In this embodiment, a plurality of gas injection ports 16 are formed on a pipe section of the gas injection pipe 15 extending into the horizontal well 18.
In this embodiment, the plurality of gas injection ports 16 are uniformly arranged along the length direction of the horizontal well 18, and a plurality of gas injection ports 16 are circumferentially provided on one cross section of the gas injection pipe 15.
In this embodiment, the gas injection pipe 15 is a high temperature resistant stainless steel pipe, and the end of the gas injection pipe 15 close to the production well 2 is not sealed, so that the injected coal bed gas in the coal reservoir stirs the migration of the water body in the horizontal well 18, the coal water contact area is increased, and the micro-impact of the injected gas can prevent the coal powder attached to the bottom of the production well 2 from burying a pump and reduce the possibility of drainage and mining interruption.
In this embodiment, the temperature of the steam output by the high-temperature steam generator 6 is 80 ℃ to 100 ℃.
The temperature of the mixed gas injected into the coal reservoir is controlled within 80-100 ℃ through steam, the steam generates a heat transfer effect and a wetting effect on the coal reservoir, the high-temperature steam directly transfers the carried heat to the coal reservoir, the top surface of the horizontal shaft is separated from the water surface along with the drainage and depressurization, and the injection of the steam enhances the wetting effect on the surface of the reservoir. The temperature of the injected steam is not too high or too low, the steam with too high temperature, such as 230 ℃ high-temperature steam, can cause clay mineral expansion in the coal bed and easily block a gas production channel of the coal bed gas, and the steam with too low temperature has poor heat transfer effect and low coal bed gas yield.
In this embodiment, the volume ratio of the mixed gas in the gas mixing box 11 is (90-95): (5-10) high-temperature steam and coal bed gas.
It should be noted that the solubility of coal bed gas, i.e., methane, at 17 deg.C is 3.5mg/100ml, i.e., 3.38%. Because the temperature of the injected gas is between 80 and 100 ℃, the solubility of the gas is increased, in order to prevent the mixed methane gas from being completely dissolved, the volume of the injected methane gas is set to be 5 to 10 percent, under the concentration, the mixed gas is injected into a coal reservoir, methane gas molecules are collapsed after the coal reservoir attaches to the wall, high temperature and vibration are generated instantly, and desorption of coal bed gas is stimulated.
It should be noted that, a small part of the coal bed gas extracted in the negative pressure extraction system is mixed and pressurized, and then is fed into the coal reservoir through the gas injection pipe 15, and the volume of the small part of the coal bed gas is the volume of the coal bed gas required in the gas mixing box 11.
In this embodiment, the gas pressure in the mixed gas pipeline 21 after being pressurized by the booster pump 12 is 1.3Pc to 1.7Pc, where Pc is the bottom hole flowing pressure of the horizontal well 18.
It should be noted that too high gas injection pressure easily causes the injected methane gas to be pressed into the coal reservoir, and the effects of displacement and gas production stimulation cannot be achieved, and too low gas injection pressure is not enough to generate water gas sloshing.
It should be noted that, because the minimum exhaustion pressure of the existing coal bed gas well is 0.2Mpa, and the normal atmospheric pressure is 0.1Mpa, in this embodiment, the negative pressure extraction pressure is set to 0.05Mpa, and the desorption and migration of the coal bed methane can be continuously promoted in the later period.
In this embodiment, the water outlet end of the water pump 3 is connected with the water storage tank 4.
The underground water pumped by the water pump 3 provides a water source for the water storage tank 4, and meanwhile, the high-temperature steam introduced into the coal reservoir comes from the coal reservoir, so that the pollution to the coal reservoir is avoided.
A method as shown in fig. 1, comprising the steps of:
constructing a U-shaped well and a coal bed gas U-shaped well gas injection circulating negative pressure extraction device;
in the embodiment, according to the construction requirement and the sequence construction of the coal bed gas U-shaped well, an engineering well 1, a production well 2 and a horizontal well 18 for communicating the engineering well 1 with the production well 2 are constructed, the horizontal well 18 is positioned in a coal reservoir, the engineering well 1 and the production well 2 are vertical wells, and conventional well cementation operation is carried out on the engineering well 1 and the production well 2;
step two, depressurizing and extracting coal bed gas:
step 201, a water suction pump 3 is turned on, the water suction pump 3 pumps water into a water storage tank 4 from a U-shaped well, the liquid level height in a production well 2 is reduced, the pressure of a coal reservoir is reduced, and the production well 2 starts to produce gas;
step 202, separating coal bed gas and water from the gas produced by the production well 2 through a gas-water separator 7, enabling the separated water to enter a water storage tank 4, and enabling the separated coal bed gas to enter a gas storage device 9;
step 203, after the flow rate of the coal bed gas separated in the gas-water separator 7 is stable, opening a first check valve 8, a second check valve 10, a third check valve 14 and a high-temperature steam generator 6, wherein the high-temperature steam generator 6 extracts water in the water storage tank 4 and outputs high-temperature steam to a gas mixing box 11, one part of the coal bed gas separated by the gas-water separator 7 enters the gas mixing box 11, and the other part of the coal bed gas enters a gas storage device 9;
the gas proportion in the gas mixing box 11 is adjusted by adjusting the opening degree of the first check valve 8 and the second check valve 10, and the mixed gas in the gas mixing box 11 is composed of the following components in volume ratio of (90-95): (5-10) high-temperature steam and coal bed gas;
step 204, pressurizing the mixed gas in the gas mixing box 11 by a booster pump 12, injecting the pressurized mixed gas into a coal reservoir through a gas injection pipe 15, desorbing the gas adsorbed on the surface of the coal in pores of the coal reservoir, separating coal bed gas and water from the gas produced by the production well 2 through a gas-water separator 7 again, pressurizing one part of the separated coal bed gas into the gas mixing box 11 together with the high-temperature steam, injecting the other part of the separated coal bed gas into a coal reservoir, and realizing the circular extraction of the coal bed gas;
step three, extracting coal bed gas under negative pressure:
when the liquid level in the U-shaped well is lowered to the coal bed roof, the water drainage and pressure reduction capacity of the water suction pump 3 is disabled, the negative pressure pump 5 is started at the moment, the pressure in the U-shaped well is reduced, the first one-way valve 8, the second one-way valve 10, the third one-way valve 14 and the high-temperature steam generator 6 are kept opened, and the coal bed gas is collected continuously until the coal bed gas extraction operation is finished.
It should be noted that. When the high-temperature steam generator 6 is started, the water amount in the current water storage tank 4 needs to be ensured to reach the lower limit of the water storage amount;
it should be noted that, after the coal bed gas mixed with the high-temperature steam and injected into the coal reservoir is acted on the coal reservoir, the coal bed gas enters the gas-water separator 7 through the production well 2 to be redistributed, no gas leakage exists in the whole process, no pollution is caused to the environment, meanwhile, the production safety is ensured, and the using effect is good.
In the embodiment, the negative pressure extraction pressure is set to be 0.05Mpa, so that desorption and migration of the coal bed methane can be continuously promoted in the later period.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims (9)
1. The utility model provides a coal bed gas U type well gas injection circulation negative pressure is taken out and is adopted device, U type well includes engineering well (1), production well (2) and communicates horizontal well (18) of engineering well (1) and production well (2), and horizontal well (18) are located coal reservoir, its characterized in that: the system comprises a negative pressure extraction system arranged at the wellhead of a production well (2), a gas injection pipe (15) arranged in a horizontal well (18), and a circulating gas supply system used for communicating the negative pressure extraction system and the gas injection pipe (15);
the circulating gas supply system converts the underground water pumped out from the negative pressure extraction system into high-temperature steam, and then the high-temperature steam is mixed with a small part of coal bed gas pumped out from the negative pressure extraction system, pressurized and supplied to the coal reservoir through a gas injection pipe (15), so that gas adsorbed on the surface of coal in pores of the coal reservoir is desorbed.
2. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 1, which is characterized in that: the negative pressure extraction system comprises a water suction pump (3) extending into the production well (2), a negative pressure pump (5) arranged at the well mouth of the production well (2) and a gas-water separator (7) communicated with the outlet of the negative pressure pump (5), a three-way pipe (17) is arranged between the negative pressure pump (5) and the well mouth of the production well (2), a first pipeline of the three-way pipe (17) is communicated with the production well (2), a second pipeline of the three-way pipe (17) is communicated with the air suction port of the negative pressure pump (5), and a third pipeline of the three-way pipe (17) is communicated with the gas-water separator (7);
the circulating gas supply system comprises a water storage pool (4), a gas mixing box (11), a first gas supply pipeline (19) used for connecting the gas mixing box (11) with the water storage pool (4), and a second gas supply pipeline (20) used for connecting a gas exhaust port of the gas mixing box (11) with a gas-water separator (7), wherein the gas mixing box (11) is communicated with a gas injection pipe (15) through a mixed gas pipeline (21), the first gas supply pipeline (19) is provided with a high-temperature steam generator (6) and a first check valve (8) arranged between the high-temperature steam generator (6) and the gas mixing box (11), the second gas supply pipeline (20) is provided with a second check valve (10), the mixed gas pipeline (21) is sequentially provided with a booster pump (12), a pressure gauge (13) and a third check valve (14), and the booster pump (12) is arranged close to the gas mixing box (11), the water outlet of the gas-water separator (7) is connected with the water storage tank (4).
3. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 2, which is characterized in that: the exhaust port of the gas-water separator (7) is divided into two paths, one path is communicated with the gas mixing box (11), and the other path is connected with the gas storage device (9).
4. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 2, which is characterized in that: and a plurality of gas injection ports (16) are formed in the pipe section of the gas injection pipe (15) extending into the horizontal well (18).
5. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 2, which is characterized in that: the temperature of the steam output by the high-temperature steam generator (6) is 80-100 ℃.
6. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 2, which is characterized in that: the mixed gas in the gas mixing box (11) is prepared from the following components in percentage by volume (90-95): (5-10) high-temperature steam and coal bed gas.
7. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 2, which is characterized in that: the gas pressure in the mixed gas pipeline (21) after being pressurized by the booster pump (12) is 1.3 Pc-1.7 Pc, wherein Pc is the bottom hole flowing pressure of the horizontal well (18).
8. The coal bed gas U-shaped well gas injection circulation negative pressure extraction device of claim 2, which is characterized in that: the water outlet end of the water suction pump (3) is connected with the water storage tank (4).
9. A method for performing coal bed gas circulating negative pressure extraction by using the coal bed gas U-shaped well gas injection circulating negative pressure extraction device of claim 2 is characterized by comprising the following steps: the method comprises the following steps:
constructing a U-shaped well and a coal bed gas U-shaped well gas injection circulating negative pressure extraction device;
step two, depressurizing and extracting coal bed gas:
step 201, turning on a water suction pump (3), pumping water from a U-shaped well into a water storage tank (4) by the water suction pump (3), reducing the liquid level in a production well (2), reducing the pressure of a coal reservoir, and starting gas production by the production well (2);
step 202, separating coal bed gas and water from the gas produced by the production well (2) through a gas-water separator (7), enabling the separated water to enter a water storage tank (4), and enabling the separated coal bed gas to enter gas storage equipment (9);
step 203, after the flow rate of the coal bed gas separated in the gas-water separator (7) is stable, opening a first one-way valve (8), a second one-way valve (10), a third one-way valve (14) and a high-temperature steam generator (6), wherein the high-temperature steam generator (6) extracts water in a water storage tank (4) and outputs high-temperature steam to a gas mixing box (11), one part of the coal bed gas separated by the gas-water separator (7) enters the gas mixing box (11), and the other part of the coal bed gas enters gas storage equipment (9);
the gas proportion in the gas mixing box (11) is adjusted by adjusting the opening degrees of the first check valve (8) and the second check valve (10), and the mixed gas in the gas mixing box (11) is prepared from the following components in percentage by volume (90-95): (5-10) high-temperature steam and coal bed gas;
204, pressurizing the mixed gas in the gas mixing box (11) by a booster pump (12), injecting the pressurized mixed gas into a coal reservoir through a gas injection pipe (15), desorbing the gas adsorbed on the surface of the coal in pores of the coal reservoir, separating coal bed gas and water from the gas produced by the production well (2) through a gas-water separator (7), pressurizing one part of the separated coal bed gas into the gas mixing box (11) together with the high-temperature steam, injecting the pressurized gas into the coal reservoir, and introducing the other part of the separated coal bed gas into a gas storage device (9) to realize the circular extraction of the coal bed gas;
step three, extracting coal bed gas under negative pressure:
when the liquid level in the U-shaped well is lowered to the coal seam roof, the water drainage and pressure reduction capacity of the water suction pump (3) is disabled, the negative pressure pump (5) is opened at the moment, the pressure in the U-shaped well is reduced, the first one-way valve (8), the second one-way valve (10), the third one-way valve (14) and the high-temperature steam generator (6) are kept opened, and the coal seam gas is collected continuously until the coal seam gas extraction operation is finished.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110337765.4A CN112901120B (en) | 2021-03-30 | 2021-03-30 | Coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110337765.4A CN112901120B (en) | 2021-03-30 | 2021-03-30 | Coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112901120A true CN112901120A (en) | 2021-06-04 |
| CN112901120B CN112901120B (en) | 2023-05-02 |
Family
ID=76109412
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110337765.4A Active CN112901120B (en) | 2021-03-30 | 2021-03-30 | Coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112901120B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1508389A (en) * | 2002-12-13 | 2004-06-30 | 石油大学(北京) | Thermal recovery method for coal seam gas |
| US20090308598A1 (en) * | 2008-06-17 | 2009-12-17 | Robert Gardes | Process to Increase the Area of Microbial Stimulation in Methane Gas Recovery in a Multi Seam Coal Bed/methane Dewatering and Depressurizing Production System Through the Use of Horizontal or Multilateral Wells |
| CN204436342U (en) * | 2015-02-02 | 2015-07-01 | 陕西龙门天地油气技术有限公司 | Coal bed gas negative pressure on ground drainage device |
| CN104790915A (en) * | 2015-04-22 | 2015-07-22 | 西南石油大学 | Coal bed methane recovery method |
| WO2017136920A1 (en) * | 2016-02-11 | 2017-08-17 | 1304342 Alberta Ltd. | Method of extracting coal bed methane using carbon dioxide |
| CN107387045A (en) * | 2017-07-20 | 2017-11-24 | 苏州大学 | A kind of coal bed gas heating exploitation system and recovery method |
| US20200340335A1 (en) * | 2018-04-28 | 2020-10-29 | China University Of Mining And Technology | System for extracting gas from tectonically-deformed coal seam in-situ by depressurizing horizontal well cavity |
-
2021
- 2021-03-30 CN CN202110337765.4A patent/CN112901120B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1508389A (en) * | 2002-12-13 | 2004-06-30 | 石油大学(北京) | Thermal recovery method for coal seam gas |
| US20090308598A1 (en) * | 2008-06-17 | 2009-12-17 | Robert Gardes | Process to Increase the Area of Microbial Stimulation in Methane Gas Recovery in a Multi Seam Coal Bed/methane Dewatering and Depressurizing Production System Through the Use of Horizontal or Multilateral Wells |
| CN204436342U (en) * | 2015-02-02 | 2015-07-01 | 陕西龙门天地油气技术有限公司 | Coal bed gas negative pressure on ground drainage device |
| CN104790915A (en) * | 2015-04-22 | 2015-07-22 | 西南石油大学 | Coal bed methane recovery method |
| WO2017136920A1 (en) * | 2016-02-11 | 2017-08-17 | 1304342 Alberta Ltd. | Method of extracting coal bed methane using carbon dioxide |
| CN107387045A (en) * | 2017-07-20 | 2017-11-24 | 苏州大学 | A kind of coal bed gas heating exploitation system and recovery method |
| US20200340335A1 (en) * | 2018-04-28 | 2020-10-29 | China University Of Mining And Technology | System for extracting gas from tectonically-deformed coal seam in-situ by depressurizing horizontal well cavity |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112901120B (en) | 2023-05-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106894799B (en) | Device and method for displacing coal bed gas by using supercritical carbon dioxide | |
| CN105971573B (en) | System and method for automatically generating CO2 foam and exploiting coalbed methane in huff-puff mode underground | |
| CN105822341B (en) | A kind of hypotonic anti-reflection system and method for coal seam supercritical carbon dioxide | |
| CN110695071A (en) | In-situ heat injection system and process for composite organic pollution site | |
| CN111561303B (en) | Device and method for improving low-coal-rank coal bed gas yield by heating coal reservoir | |
| CN207761627U (en) | A kind of oil well air water mixed water injection device | |
| CN211692422U (en) | Carbon dioxide injection huff and puff oil extraction ground device for oil field | |
| CN108019190A (en) | A kind of totally-enclosed mixes defeated decompression circulation gas lift system | |
| WO2024087979A1 (en) | Method for enhancing coalbed methane exploitation and co2 storage in unworkable seam | |
| CN102392646B (en) | Marine gas hydrate electronic-spraying pump composite exploitation method and apparatus | |
| CN203531877U (en) | Underground coal mine fracturing connecting device | |
| CN108442914A (en) | A kind of system and method for oil shale in-situ cracking | |
| CN207750066U (en) | A kind of totally-enclosed mixes defeated decompression cycle gas lift system | |
| CN114412419B (en) | Efficient closed-loop extraction method for superposed coal bed gas reservoir | |
| CN109630081A (en) | A kind of coal bed drilling note high pressure-temperature vapor strengthens coal bed gas drainage device and method | |
| CN209959220U (en) | Injection device for petroleum recovery | |
| CN114876437A (en) | Coal bed in-situ hydrogen production method utilizing supercritical water | |
| CN107023284A (en) | A kind of static expanding agent injected system and method for implanting | |
| CN111911117B (en) | Combustible ice exploitation pipe column heated by stratum energy and operation method thereof | |
| CN102747993A (en) | Liquid foaming agent injection method | |
| CN113236338A (en) | Mine gas permeability increasing method and device | |
| CN113738326B (en) | Carbon dioxide anhydrous sand fracturing system and method | |
| CN112901120A (en) | Coal bed gas U-shaped well gas injection circulation negative pressure extraction device and method | |
| CN105114045A (en) | CCUS system for extracting oil based on gas lifting method and application thereof | |
| CN210816696U (en) | In-situ heat injection system for composite organic pollution site |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |