CN113356825B - Device and method for exploiting shale gas by combining microwave irradiation with dry ice fracturing - Google Patents
Device and method for exploiting shale gas by combining microwave irradiation with dry ice fracturing Download PDFInfo
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- CN113356825B CN113356825B CN202110818807.6A CN202110818807A CN113356825B CN 113356825 B CN113356825 B CN 113356825B CN 202110818807 A CN202110818807 A CN 202110818807A CN 113356825 B CN113356825 B CN 113356825B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B43/25—Methods for stimulating production
- E21B43/26—Methods for stimulating production by forming crevices or fractures
- E21B43/267—Methods for stimulating production by forming crevices or fractures reinforcing fractures by propping
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP 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
- E21B43/164—Injecting CO2 or carbonated water
Abstract
The invention discloses a device and a method for exploiting shale gas by microwave irradiation and dry ice fracturing, wherein the device comprises a microwave irradiation component, a dry ice fracturing component and a shale gas collecting component, the microwave irradiation component comprises a microwave generator, a waveguide tube and a microwave emitter which are sequentially connected, and microwaves irradiate shale layers outside a horizontal well barrel through a perforation; the dry ice fracturing component comprises a dry ice preparation device, a high-pressure delivery pump, a dry ice delivery pipe control valve and a dry ice delivery pipe which are sequentially connected, the dry ice preparation device and the high-pressure delivery pump are both arranged outside the shale gas well, the tail end of the dry ice delivery pipe penetrates through a vertical shaft and is arranged in a horizontal shaft, dry ice prepared in the dry ice preparation device is delivered into the horizontal shaft through the high-pressure delivery pump and the dry ice delivery pipe, and fracturing is performed on shale layers through perforation. The method can promote the conversion of the adsorbed gas into the free gas, accelerate the resolution rate, improve the fracturing effect, reduce the mining cost and improve the exploitation benefit of the shale gas.
Description
Technical Field
The invention belongs to the technical field related to shale gas exploitation, and particularly relates to a device and a method for exploiting shale gas by combining microwave irradiation and dry ice fracturing.
Background
At present, global traditional energy is highly exhausted, the demand for clean energy is continuously expanded, and the popularization and the use of the clean energy in the global range are urgently needed to solve the problems of energy shortage, ecological environment deterioration, global warming and the like. With the continuous progress of horizontal wells and fracturing technologies, the exploration and development of shale gas by human beings are gradually forming hot tides, and the shale gas is likely to occupy a main position in a global primary energy consumption structure.
The main component of the shale gas is CH 4 Often present in shale formations in adsorbed and free states. The shale permeability is extremely low, generally less than 0.001mD, which enables the shale gas reservoir to have the characteristic of self-generation and self-storage. Different from a conventional natural gas reservoir, more than 90% of shale gas reservoirs need to be subjected to reservoir transformation during exploitation, so that the reservoirs generate complex fracture networks, and shale gas in adsorption states and free states in fractures and pores is successfully extracted, so that the reservoir transformation effect and the analysis rate are particularly important for the exploitation of the shale gas.
The hydraulic fracturing is a traditional technical means for improving a shale gas exploitation reservoir, namely high-pressure water is pumped into a shale gas well, so that the aim of directly fracturing rocks after the high-pressure water passes through perforations is fulfilled. However, the development of the fracturing technology is also limited by a plurality of adverse factors such as large water resource consumption, unfavorable use in arid regions, easy water lock effect, induced earthquake, environmental pollution and the like. Even more, some countries and regions have strictly prohibited the use of hydraulic fracturing for the recovery of shale gas for resource and environmental considerations.
In order to meet the high standard and strict requirements on factors such as reservoir properties, geographical environments and the like in shale gas exploitation and solve the worldwide problem of poor development effect, the demand for developing the waterless fracturing technology to exploit shale gas is more and more urgent and is highly emphasized by countries in the world.
The patent utilizes heat injection to shale layers to improve the analysis rate and the flow rate of shale gas, so as to achieve the exploitation efficiency of the shale gas, but the disclosure content of the patent can not ensure the seam making effect of thermal stress, and the flow is complex and the cost is high;
the application publication number is CN 110159241A's Chinese patent application, discloses a microwave irradiation and hydraulic fracturing are cooperative to exploit shale gas's device, and the device utilizes microwave irradiation hydraulic fracturing's shale layer, and the shale layer heats up the thermal stress that produces fast makes the hydraulic fracture that hydraulic fracturing produced before further expand, has improved shale gas extraction rate to a certain extent. However, the disclosure of this patent does not address the ecological and other problems associated with reliance on hydraulic fracturing;
the Chinese patent with the publication number of CN105822275B discloses a technology and a method for fracturing and crack-making aiming at shale, and the technology fractures shale gas by stages through microwave irradiation and liquid nitrogen, so as to solve the problem that in the hydraulic fracturing process, the volatilization speed of a liquid phase near a well hole is slow, which causes water lock to block a seepage passage. However, the analysis rate of shale gas is not considered in the technology, the fracturing effect of different reservoir environments cannot be fundamentally guaranteed by one-time fracturing, and the liquid nitrogen preparation and conveying cost is high.
Therefore, how to accelerate the shale gas desorption rate, ensure the fracturing effect and reduce the cost is an urgent problem to be solved in shale gas exploitation.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides the device and the method for exploiting the shale gas by combining microwave irradiation and dry ice fracturing, which have the advantages of better fracturing effect, higher shale gas analysis rate and lower cost.
The device for exploiting the shale gas by microwave irradiation and dry ice fracturing is arranged in a shale gas well and comprises a microwave irradiation assembly, a dry ice fracturing assembly and a shale gas collecting assembly, wherein the shale gas well comprises a vertical shaft and a horizontal shaft communicated with the vertical shaft, and a perforation is formed in the wall of the horizontal shaft; the microwave irradiation assembly comprises a microwave generator, a waveguide tube and a microwave emitter which are sequentially connected, the microwave emitter is arranged in the horizontal shaft and corresponds to the perforation, the microwave generator transmits microwaves to the microwave emitter through the waveguide tube, and the microwave emitter performs microwave irradiation on the shale layer outside the horizontal shaft through the perforation; the dry ice fracturing component comprises a dry ice preparation device, a high-pressure delivery pump, a dry ice delivery pipe control valve and a dry ice delivery pipe which are sequentially connected, the dry ice preparation device and the high-pressure delivery pump are both arranged outside the shale gas well, the tail end of the dry ice delivery pipe penetrates through a vertical shaft and is arranged in a horizontal shaft, dry ice prepared in the dry ice preparation device is delivered into the horizontal shaft through the high-pressure delivery pump and the dry ice delivery pipe, and a shale layer is fractured through perforation; the shale gas collecting assembly comprises a shale gas storage device, an air extracting pump and an air extracting control valve which are sequentially connected, and the air extracting control valve is communicated with the front end of the dry ice conveying pipe.
A first packer is disposed in the vertical wellbore below the horizontal wellbore.
And a second packer is arranged at the tail end of the horizontal shaft.
And a material supplementing opening for adding the propping agent is arranged between the dry ice preparation device and the high-pressure delivery pump.
In order to further reduce transmission loss, the microwave irradiation assembly further comprises a microwave converter arranged in the vertical shaft, the microwave generator is arranged outside the shale gas well, the microwave output end of the microwave generator is connected with the microwave input end of the microwave converter through a cable, and the microwave output end of the microwave converter is connected with the microwave input end of the waveguide tube.
The dry ice conveying pipe comprises a main pipe and a plurality of branch pipes, the main pipe penetrates through the vertical shaft and is arranged in the horizontal shaft, and the branch pipes are connected to the main pipe at the position corresponding to the perforation.
And a temperature alarm is also arranged outside the shale gas well, and a temperature sensor on the temperature alarm extends into the shale gas well and is arranged at the tail end of the main pipe.
The branch pipe diameter is equal to the perforation diameter and the branch pipe diameter is 1/4 to 1/3 of the main pipe diameter.
The dry ice is a stream of dry ice.
The invention relates to a method for exploiting shale gas by microwave irradiation and dry ice fracturing, which comprises the following steps:
s1, arranging a vertical shaft and a horizontal shaft in the stratum in a communicating manner, wherein an overburden layer is arranged outside the vertical shaft, the horizontal shaft is arranged in the shale layer, and a perforation is formed in the wall of the horizontal shaft;
s2, erecting a waveguide tube in the horizontal well barrel, connecting a microwave emitter arranged corresponding to the perforation on the output end of the waveguide tube, and connecting the microwave generator to the input end of the waveguide tube;
s3, arranging a dry ice conveying pipe in the shale gas well, arranging a dry ice preparation device, a high-pressure conveying pump and a dry ice conveying pipe control valve which are sequentially connected outside the shale gas well, arranging a shale gas storage device, an air suction pump and an air suction control valve which are sequentially connected outside the shale gas well, and arranging an outlet of the dry ice conveying pipe control valve and an inlet of the air suction control valve in a way of being communicated with the front end of the dry ice conveying pipe;
s4, starting a microwave generator, and exciting microwaves by the microwave emitter to irradiate and heat the shale layer through the perforation;
s5, gradually raising the temperature of the shale layer, and turning off the microwave generator when the temperature in the horizontal shaft reaches the upper limit temperature set by the temperature alarm;
s6, opening a high-pressure delivery pump and a dry ice delivery pipe control valve, continuously delivering dry ice into the horizontal shaft by using the dry ice delivery pipe, and fracturing the high-temperature shale layer by using dry ice in the horizontal shaft through perforation;
s7, when the temperature in the horizontal shaft is lower than the lower limit temperature set by the temperature alarm, closing the high-pressure delivery pump and the dry ice delivery pipe control valve, and opening the microwave generator again to irradiate the fractured fracture network again;
and S8, when the temperature in the horizontal shaft is heated to 1/2 of the upper limit temperature set by the temperature alarm, closing the microwave generator, opening the air suction pump and the air suction control valve, and collecting and gathering the shale gas into the shale gas storage device.
Compared with the prior art, the invention has the following advantages:
1. shale gas is widely adsorbed in the shale layer, and the shale can effectively absorb the microwave, and the shale layer is irradiated to the microwave, on the one hand, the temperature of a reservoir layer is improved, the adsorbed gas is promoted to be converted into free gas, the analysis rate is accelerated, and on the other hand, the thermal stress generated by microwave irradiation is also beneficial to rock breaking and the shale gas flow which helps the analysis.
2. The dry ice is injected, so that a high-temperature shale layer irradiated by microwaves can form a complex fracture network due to severe cold impact, the cold impact formed fracture network is further impacted by vaporization of the dry ice, and the fracturing effect is greatly improved; at the same time, due to CO 2 Has a far greater adsorption capacity than CH 4 The vaporized dry ice can effectively adsorb CH on the surface of the rock 4 And replacement is performed, so that the resolution rate is rapidly accelerated.
3. The dry ice fracturing can reduce the waste of water resources and environmental pollution, reduce the mining cost, improve the exploitation benefit of the shale gas, and ensure that the analysis rate of absorbing the shale gas is accelerated while the fracturing effect is improved; meanwhile, geological storage of CO can be promoted to a certain extent 2 And the greenhouse effect is relieved.
The invention is relatively simple, the technology is reliable, the operation mode is flexible, a development mode of repeated fracturing for many times can be developed according to the characteristics of different reservoirs, and the method has good application prospect and wide practical engineering application in the field of shale gas exploitation engineering.
Drawings
Fig. 1 is a schematic structural diagram of a device for exploiting shale gas by combining microwave irradiation and dry ice fracturing.
The labels shown in the figures and the corresponding component names are:
1. a vertical wellbore; 2. a horizontal wellbore; 3. perforating; 4. a microwave generator; 5. a waveguide tube; 6. a microwave emitter; 7. a shale layer; 8. a dry ice preparation device; 9. a high pressure delivery pump; 10. a dry ice delivery pipe control valve; 11. a shale gas storage device; 12. an air pump; 13. a gas pumping control valve; 14. a first packer; 15. a second packer; 16. a material supplementing port; 17. a microwave converter; 18. a cable; 19. a main pipe; 20. a branch pipe; 21. a temperature alarm; 22. a temperature sensor.
Detailed Description
As can be seen from fig. 1, the device for exploiting shale gas by microwave irradiation and dry ice fracturing, which is installed in a shale gas well, comprises a microwave irradiation assembly, a dry ice fracturing assembly and a shale gas collection assembly, wherein,
the shale gas well comprises a vertical shaft 1 and a horizontal shaft 2, wherein the vertical shaft 1 is vertically arranged in an overlying rock stratum, the top of the vertical shaft 1 is arranged flush with the surface of the ground, the bottom of the vertical shaft 1 is arranged lower than the shale stratum 7, the horizontal shaft 2 is horizontally arranged in the shale stratum 7 on one side of the vertical shaft 1, the front end of the horizontal shaft 2 is vertically communicated with the vertical shaft 1, a plurality of perforation holes 3 which are symmetrically arranged up and down are formed in the wall of the tail end of the horizontal shaft 2, a first packer 14 is hermetically connected in the vertical shaft 1 below the horizontal shaft 2, and a second packer 15 is hermetically connected at the tail end of the horizontal shaft 2;
the microwave irradiation assembly comprises a microwave generator 4 and a microwave converter 17, the microwave irradiation device comprises a waveguide tube 5 and a microwave emitter 6, wherein a microwave generator 4 is arranged on the ground surface on one side of a vertical shaft 1, a microwave converter 17 is arranged on a first packer 14 in the vertical shaft 1, the microwave output end of the microwave generator 4 is connected with the microwave input end of the microwave converter 17 through a cable 18, the microwave emitter 6 is horizontally arranged in a horizontal shaft 2 corresponding to a perforation 3, the microwave input end of the waveguide tube 5 is connected with the microwave output end of the microwave converter 17, the microwave output end of the waveguide tube 5 is bent and extends into the horizontal shaft 2 to be connected with the microwave input end of the microwave emitter 6, the microwave generator 4 transmits microwaves to the microwave emitter 6 through the microwave converter 17 and the waveguide tube 5, and the microwave emitter 6 irradiates a shale layer 7 outside the horizontal shaft 2 with microwaves through the perforation 3;
the dry ice fracturing assembly comprises a dry ice preparation device 8 and a high-pressure delivery pump 9, the dry ice conveying pipe comprises a main pipe 19 and a plurality of branch pipes 20, a dry ice preparation device 8 and a high-pressure conveying pump 9 are arranged on the ground surface on one side of a vertical shaft 1, an outlet of the dry ice preparation device 8 is communicated with an inlet of the high-pressure conveying pump 9 through a pipeline, an outlet of the high-pressure conveying pump 9 is communicated with an inlet of the dry ice conveying pipe control valve 10 through a pipeline, an outlet of the dry ice conveying pipe control valve 10 is communicated with the front end of the main pipe 19, the tail end of the main pipe 19 penetrates through the vertical shaft 1 and is arranged in a horizontal shaft 2, the branch pipes 20 are connected to the main pipe 19 corresponding to a perforation 3 in a one-to-one mode, and dry ice prepared in the dry ice preparation device 8 is conveyed into the horizontal shaft 2 through the high-pressure conveying pump 9 and the dry ice conveying pipe and then is fractured on a shale layer 7 through the perforation 3;
the shale gas collecting assembly comprises a shale gas storage device 11, an air extracting pump 12 and an air extracting control valve 13, wherein the shale gas storage device 11 and the air extracting pump 12 are both arranged on the ground surface on the other side of the vertical shaft 1, an inlet of the shale gas storage device 11 is communicated with an outlet of the air extracting pump 12 through a pipeline, an inlet of the air extracting pump 12 is communicated with an outlet of the air extracting control valve 13 through a pipeline, and an inlet of the air extracting control valve 13 is communicated with the front end of a main pipe 19.
As can be seen from fig. 1, a replenishment port 16 for adding proppant is provided on the pipeline between the dry ice preparation device 8 and the high-pressure delivery pump 9.
As can be seen from fig. 1, a temperature alarm 21 is further arranged outside the shale gas well, and a temperature sensor 22 on the temperature alarm 21 extends into the shale gas well and is arranged at the tail end of the main pipe 19 for recording data and feeding back to the microwave generator 4 and the high-pressure delivery pump 9.
In the invention, the main pipe 19 and the branch pipes 20 are connected by gluing through a sealant, the main pipe 19 and the branch pipes 20 are both made of high-low temperature heat-insulating stainless steel materials, the diameter of each branch pipe 20 is equal to that of each perforation 3, and the diameter of each branch pipe 20 is 1/4-1/3 of the diameter of the main pipe 19.
In the present invention, the dry ice is a flow of dry ice.
The invention relates to a method for exploiting shale gas by microwave irradiation and dry ice fracturing, which comprises the following steps:
s1, according to the fracturing position of shale gas exploitation, a vertical shaft 1 is constructed in an overlying rock layer of a shale layer 7, a horizontal shaft 2 vertically communicated with the vertical shaft 1 is constructed in the shale layer 7, and a perforation 3 is formed in the wall of the tail end of the horizontal shaft 2;
s2, erecting a microwave emitter 6 in the horizontal shaft 2 corresponding to the perforation 3, placing a microwave converter 17 in the vertical shaft 1, connecting a waveguide 5 between the microwave output end of the microwave converter 17 and the microwave input end of the microwave emitter 6, placing a microwave generator 4 on the ground surface on one side of the vertical shaft 1, and connecting the microwave output end of the microwave generator 4 with the microwave input end of the microwave converter 17 through a cable 18;
s3, arranging a dry ice conveying pipe in the shale gas well, arranging a dry ice preparation device 8, a high-pressure conveying pump 9 and a dry ice conveying pipe control valve 10 which are sequentially connected on the ground surface of one side outside the vertical shaft 1, arranging a shale gas storage device 11, an air suction pump 12 and an air suction control valve 13 which are sequentially connected on the ground surface of the other side outside the vertical shaft 1, and arranging an outlet of the dry ice conveying pipe control valve 10 and an inlet of the air suction control valve 13 to be communicated with the front end of the dry ice conveying pipe;
s4, starting the microwave generator 4, exciting microwaves to irradiate and heat the shale layer 7 through the perforation 3 by the microwave emitter 6, and rapidly heating the shale layer 7 after the microwaves irradiate for a certain time because the shale can absorb the microwaves, so that the shale gas analysis speed is increased, and the temperature of the shale layer 7 and the shale gas analysis speed are improved;
s5, gradually raising the temperature of the shale layer 7 to generate thermal stress so that the shale generates thermal damage, and turning off the microwave generator 4 when the temperature in the horizontal shaft 2 reaches the upper limit temperature set by the temperature alarm 21;
s6, opening the high-pressure delivery pump 9 and the dry ice delivery pipe control valve 10, adding the propping agent through the material supplementing opening 16, and mixing the propping agent and the dry ice to form dry matterThe ice flow fracturing fluid is continuously conveyed into the horizontal shaft 2 by using a dry ice conveying pipe, the dry ice flow fracturing fluid in the horizontal shaft 2 fractures the shale layer 7 at high temperature through the perforation 3, the shale layer 17 generates cold impact due to severe temperature gradient difference, the shale layer 7 is fractured to form a complex fracture network, the dry ice is rapidly vaporized, the volume is violently expanded, and the formed fracture network is expanded again; at the same time, due to CO 2 Has an adsorption capacity far greater than that of CH 4 The vaporized dry ice can effectively adsorb CH on the surface of the rock 4 The displacement is realized, and the resolution rate is quickly accelerated;
s7, when the temperature in the horizontal shaft 2 is lower than the lower limit temperature set by the temperature alarm 21, closing the high-pressure delivery pump 9 and the dry ice delivery pipe control valve 10, starting the microwave generator 4 again to irradiate the fractured and formed fracture network again, further expanding the fractures generated by the dry ice fracturing by generating thermal stress and promoting the shale gas to be further analyzed;
and S8, when the temperature in the horizontal shaft 2 is heated to 1/2 of the upper limit temperature set by the temperature alarm 21, closing the microwave generator 4, opening the air suction pump 12 and the air suction control valve 13, extracting shale gas generated after multiple times of sufficient fracturing, and collecting and gathering the shale gas into the shale gas storage device 11.
In the using process of the invention, the CO possibly mixed in the extraction process is possibly mixed in consideration of the principle of dry ice fracturing 2 Therefore, before being put into use, impurity removal treatment is carried out.
The dry ice fracturing method is simple and reliable, mature in technology and low in economic cost, can greatly improve the fracturing effect of the shale layer caused by temperature stress under dry ice fracturing, can also strengthen the shale gas analysis rate, improves the exploitation effect, and avoids the prominent problems caused by the traditional hydraulic fracturing technology, such as large water resource consumption, induced earthquake, environmental pollution and the like; and the development mode of multiple fracturing can be realized by setting the parameters of the temperature alarm, and the engineering application fields of microwave irradiation and dry ice are enlarged.
In the using process of the invention, the preset value of the temperature alarm can be reasonably adjusted according to the geological environment of the reservoir where the fractured horizontal shaft 2 is located, and irradiation-fracturing repeated fracturing can be timely carried out and flexibly applied.
Solid CO existing at-78.5 ℃ under standard atmospheric pressure 2 Called dry ice, which has a cold storage capacity 2 times that of ice. The dry ice absorbs heat and then is sublimated into CO 2 Gas, no residue, no toxicity, no peculiar smell, and simultaneously, the volume of the gas can expand by about 600-800 times rapidly; so that if in a confined space, the converted gaseous CO 2 It generates an ultra-high pressure to a limited space and may generate a severe explosion impact. When CO is present 2 Is in a supercritical state when the temperature and the pressure of (2) reach 31.1 ℃ and 7.4 MPa. Supercritical carbon dioxide has both gas and liquid properties: the density is high, usually hundreds times of that of gas, and is similar to that of liquid; the viscosity is low, two orders of magnitude less than that of the liquid, and the diffusion coefficient is high, about 10-100 times that of the liquid.
Therefore, a certain temperature difference can be formed by injecting dry ice into the shale reservoir, and the shale layer can be cracked by temperature stress generated by cold impact to form a complex fracture network, so that the yield of shale gas is improved. CO after gasification 2 Has high diffusivity, low viscosity and low surface tension, is easier to penetrate into the microcracks and pores of the rock than water, and generates the same fracture degree, and the required gas pressure is smaller than the water pressure. At the same time, CO 2 Has strong adsorption capacity of CH 4 4-20 times of that of CO, CO 2 Can effectively adsorb CH on the surface of the rock 4 And (4) replacing.
The dry ice is injected into the shale layer, the cold shock is utilized to generate stress to crack the reservoir layer, so that the reservoir layer can be effectively prevented from being damaged and water resources are effectively wasted, the environmental problem caused by hydraulic fracturing is solved to a certain extent, and the use area is not limited; at the same time, CO can also be sealed off geologically 2 And the greenhouse effect is relieved. However, the temperature stress generated by the fracturing mode under different temperature and pressure conditions is very large, most reservoirs which are commercially and successfully exploited in China are shallow layers at present, the temperature is below 100 ℃, and the instantaneous temperature difference of the dry ice injected into the shale layer is limited, so that the simple dry ice fracturing probably cannot ensure the fracturing and seam-making effects. To this endMicrowave irradiation is matched with dry ice fracturing to form a new shale gas efficient yield increase technology, and dry ice fracturing crack making and CO are planned 2 The shale gas is displaced and adsorbed, the reservoir is heated by microwave irradiation, the shale gas is accelerated to be resolved at high temperature, and multiple fracturing can be well formed in a matching way; the method can ensure that the shale gas analysis rate is accelerated, the fracturing effect is ensured, the system process is simple, the dry ice preparation and conveying cost is low, the shale gas exploitation effect of the target reservoir can be improved to the maximum extent, and the method has important practical significance for shale gas development.
Claims (8)
1. The utility model provides a device that microwave irradiation unites dry ice fracturing exploitation shale gas, installs in the shale gas well, its characterized in that: comprises a microwave irradiation component, a dry ice fracturing component and a shale gas collecting component,
the shale gas well comprises a vertical shaft (1) and a horizontal shaft (2) communicated with the vertical shaft, and perforations (3) are formed in the wall of the horizontal shaft;
the microwave irradiation assembly comprises a microwave generator (4), a waveguide tube (5) and a microwave emitter (6) which are sequentially connected, the microwave emitter is arranged in the horizontal shaft and corresponds to the perforation, the microwave generator transmits microwaves to the microwave emitter through the waveguide tube, and the microwave emitter irradiates the shale layer (7) outside the horizontal shaft through the perforation to form a high-temperature shale layer;
the dry ice fracturing assembly comprises a dry ice preparation device (8), a high-pressure delivery pump (9), a dry ice delivery pipe control valve (10) and a dry ice delivery pipe which are sequentially connected, wherein the dry ice delivery pipe comprises a main pipe (19) and a plurality of branch pipes (20), the main pipe penetrates through a vertical shaft and is arranged in a horizontal shaft, the branch pipes are connected to the main pipe corresponding to a perforation, a temperature alarm (21) is further arranged outside a shale gas well, a temperature sensor (22) on the temperature alarm extends into the shale gas well and is arranged at the tail end of the main pipe, the dry ice preparation device and the high-pressure delivery pump are both arranged outside the shale gas well, dry ice prepared in the dry ice preparation device is delivered into the horizontal shaft through the high-pressure delivery pump and the dry ice delivery pipe, and a high-temperature shale layer is fractured through the perforation;
the shale gas collection assembly comprises a shale gas storage device (11), an air suction pump (12) and an air suction control valve (13) which are connected in sequence, and the air suction control valve is communicated with the front end of a dry ice conveying pipe.
2. The device for exploiting shale gas by microwave irradiation and dry ice fracturing in combination with claim 1 is characterized in that: a first packer (14) is disposed in the vertical wellbore below the horizontal wellbore.
3. The device for exploiting shale gas by microwave irradiation and dry ice fracturing in combination with claim 1 is characterized in that: a second packer (15) is arranged at the end of the horizontal shaft.
4. The device for exploiting shale gas by microwave irradiation and dry ice fracturing in combination with claim 1 is characterized in that: a material supplementing opening (16) used for adding propping agent is arranged between the dry ice preparation device and the high-pressure delivery pump.
5. The device for exploiting shale gas by microwave irradiation and dry ice fracturing in combination with claim 1 is characterized in that: the microwave irradiation assembly further comprises a microwave converter (17) arranged in the vertical shaft, the microwave generator is arranged outside the shale gas well, a microwave output end of the microwave generator is connected with a microwave input end of the microwave converter through a cable (18), and a microwave output end of the microwave converter is connected with a microwave input end of the waveguide tube.
6. The device for exploiting shale gas by microwave irradiation and dry ice fracturing in combination with claim 1 is characterized in that: the branch pipe diameter is equal to the perforation diameter and the branch pipe diameter is 1/4 to 1/3 of the main pipe diameter.
7. The device for exploiting shale gas by microwave irradiation and dry ice fracturing in combination with claim 1 is characterized in that: the dry ice is a stream of dry ice.
8. A method for exploiting shale gas by combining microwave irradiation and dry ice fracturing is characterized by comprising the following steps:
s1, arranging a vertical shaft (1) and a horizontal shaft (2) in the stratum in a communicating manner, wherein an overburden layer is arranged outside the vertical shaft, the horizontal shaft is arranged in a shale layer (7), and a perforation (3) is formed in the wall of the horizontal shaft;
s2, erecting a waveguide tube (5) in the horizontal well barrel, connecting a microwave emitter (6) which is arranged corresponding to the perforation on the output end of the waveguide tube, and connecting a microwave generator (4) to the input end of the waveguide tube;
s3, arranging a dry ice conveying pipe in the shale gas well, arranging a dry ice preparation device (8), a high-pressure conveying pump (9) and a dry ice conveying pipe control valve (10) which are sequentially connected outside the shale gas well, arranging a shale gas storage device (11), an air suction pump (12) and an air suction control valve (13) which are sequentially connected outside the shale gas well, and arranging an outlet of the dry ice conveying pipe control valve and an inlet of the air suction control valve in a communicated manner with the front end of the dry ice conveying pipe;
s4, starting a microwave generator, and exciting microwaves by the microwave emitter to irradiate and heat the shale layer through the perforation;
s5, gradually raising the temperature of the shale layer, and turning off the microwave generator when the temperature in the horizontal shaft reaches the upper limit temperature set by the temperature alarm;
s6, opening a high-pressure delivery pump and a dry ice delivery pipe control valve, continuously delivering dry ice into the horizontal shaft by using the dry ice delivery pipe, and fracturing the high-temperature shale layer by using dry ice in the horizontal shaft through perforation;
s7, when the temperature in the horizontal shaft is lower than the lower limit temperature set by the temperature alarm, closing the high-pressure delivery pump and the dry ice delivery pipe control valve, and opening the microwave generator again to irradiate the fractured fracture network again;
and S8, when the temperature in the horizontal shaft is heated to 1/2 of the upper limit temperature set by the temperature alarm, closing the microwave generator, opening the air suction pump and the air suction control valve, and collecting and gathering the shale gas into the shale gas storage device.
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| US20040200618A1 (en) * | 2002-12-04 | 2004-10-14 | Piekenbrock Eugene J. | Method of sequestering carbon dioxide while producing natural gas |
| DE102011077062A1 (en) * | 2011-06-07 | 2012-12-13 | Siemens Aktiengesellschaft | Process for mining shale gas |
| CN106481328B (en) * | 2016-09-23 | 2018-12-25 | 太原理工大学 | A method of the artificial heat storage of hot dry rock is built using graininess dry ice |
| CN106285604B (en) * | 2016-11-01 | 2019-03-01 | 中国矿业大学 | Microwave-assisted supercritical carbon dioxide cyclic fracturing system and method |
| CN110159241A (en) * | 2019-06-25 | 2019-08-23 | 中国矿业大学(北京) | A kind of microwave irradiation cooperates with the device of exploitation shale gas with hydraulic fracturing |
| CN110439520B (en) * | 2019-07-23 | 2022-02-11 | 河海大学 | Intrinsic safety type dry ice powder static pneumatic fracturing simulation device and application method thereof |
| CN112943191A (en) * | 2021-01-27 | 2021-06-11 | 西安科技大学 | Method for increasing permeability and displacing coal seam gas by filling dry ice in drill hole |
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2021
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