CN118030005A - Liquid nitrogen fracturing device and use method - Google Patents

Abstract

The application provides a liquid nitrogen fracturing device and a using method thereof, and relates to the field of liquid nitrogen fracturing. A liquid nitrogen fracturing device comprising: the bottom of the sealing boss is fixedly connected with an embedded outer pipe sleeve; one side of the sealing boss is provided with a fixing frame, one side of the fixing frame far away from the sealing boss is communicated with a cylinder barrel, a primary pressurizing assembly is arranged in the fixing frame, and a fracturing assembly is arranged on the outer side of the sealing boss; the inner cavity of the pre-buried outer pipe sleeve is provided with a secondary pressurizing assembly. According to the liquid nitrogen fracturing device and the application method, the primary pressurizing assembly, the secondary pressurizing assembly and the fracturing assembly are matched, nitrogen, liquid nitrogen, hot nitrogen and water are alternately used as fracturing conductors, uniform and effective fracturing treatment is carried out on a well in a mode of combining filling pressurization and driving extrusion, complex networking of cracks of rock and soil layers on the inner wall of the well is achieved, openings and deep fracturing of the cracks are achieved in place, and exploitation of underground oil and gas is facilitated.

Description

Liquid nitrogen fracturing device and use method

Technical Field

The application relates to the technical field of liquid nitrogen fracturing, in particular to a liquid nitrogen fracturing device and a using method thereof.

Background

The fracturing is a method for forming cracks on an oil and gas layer by utilizing the hydraulic action in the oil extraction, coal mining or gas extraction process, is also called hydraulic fracturing, and is characterized in that the fracturing artificially cracks the stratum, improves the flowing environment of oil in the underground, increases the yield of an oil well, and plays an important role in improving the flowing condition of the bottom of the oil well, slowing down the interlayer and improving the oil layer utilization condition.

In the prior art (patent application publication No. CN107401400B, patent name is a fracturing system), the rock stratum type of the top plate or the bottom plate of the coal bed is determined through the identification equipment, the perforation position and the perforation proportion coefficient are determined by the control equipment according to the rock stratum type of the top plate or the bottom plate of the coal bed, and the fracturing fluid is injected into the perforation section by the liquid injection equipment, so that longer cracks are formed, stable gas production in a long time is ensured, the gas production of the coal bed gas is improved, and the recovery ratio of the coal bed gas is improved. In the process of realizing the technical scheme, at least the following problems are found in the prior art.

For traditional well fracturing means, the fracturing conductivity that most adopted is water, and during the fracturing, a large amount of water is needed, not only causes the waste of a large amount of water resources, but also during hydraulic fracturing, can not effectively support and temporarily block the fracturing fracture, and the hydraulic fracturing is easy to complete, and the fracture formed by the fracturing is retracted and collapsed, and the fracture formed by the hydraulic fracturing is single, and the opening and depth are insufficient, so that the underground oil and gas exploitation amount is reduced.

Disclosure of Invention

The application aims to at least solve the technical problems that nitrogen, liquid nitrogen, hot nitrogen and water can not be alternately used as fracturing conductors in the prior art, the well is uniformly and effectively subjected to fracturing treatment in a mode of combining filling pressurization and driving extrusion, complicated networking of cracks of rock and soil layers on the inner wall of the well is not realized, and the openings and the depths of the cracks are insufficient, so that the exploitation of underground oil and gas is not facilitated. Therefore, the application provides a liquid nitrogen fracturing device and a using method thereof.

According to an embodiment of the application, a liquid nitrogen fracturing device comprises: the bottom of the sealing boss is fixedly connected with an embedded outer pipe sleeve;

One side of the sealing boss is provided with a fixing frame, one side of the fixing frame far away from the sealing boss is communicated with a cylinder barrel, a primary pressurizing assembly is arranged in the fixing frame, and a fracturing assembly is arranged on the outer side of the sealing boss;

The inner cavity of the pre-buried outer pipe sleeve is provided with a secondary pressurizing assembly.

Preferably, the one-level pressurization subassembly includes the double-end motor, the double-end motor is fixed and is close to one side of sealed boss at the mount, and a output shaft fixedly connected with of double-end motor and the spill pole of mount cooperation use, the center department rotation of spill pole is connected with changeing the cover, and changeing the table wall fixedly connected with link arm of cover, another head of link arm articulates there is with cylinder barrel sliding fit's piston seat, and cylinder barrel's gas vent has the pressurized tank through return bend intercommunication, is provided with discharge valve on the return bend, the three gas vent of pressurized tank communicates respectively has first pressurization pipe, second pressurization pipe and third pressurization pipe, and first pressurization pipe, second pressurization pipe and third pressurization pipe all adopt the thickening steel pipe material.

Preferably, the fracturing assembly comprises a first three-way valve, a second three-way valve and a third three-way valve, the first three-way valve, the second three-way valve and the third three-way valve are respectively communicated with one ends of a first pressurizing pipe, a second pressurizing pipe and a third pressurizing pipe, which are far away from the pressurizing tank, one ends of the first three-way valve, the second three-way valve and the third three-way valve are respectively communicated with a nitrogen tank, a liquid nitrogen tank and a water purifying tank, the other ends of the first three-way valve, the second three-way valve and the third three-way valve are respectively communicated with a first supply pipe, a second supply pipe and a third supply pipe, the bottoms of the first supply pipe, the second supply pipe and the third supply pipe are communicated with telescopic pipes, the bottoms of the three groups of telescopic pipes are communicated with an injection head, and an electromagnetic valve is arranged on the injection head.

Preferably, the second-stage pressurizing assembly comprises a first electric push rod, the top at the spill pole is fixed to the first electric push rod, and the piston rod fixedly connected with first location head of first electric push rod, the top of first location head is provided with first drive round gear, and the center department of first drive round gear bottom set up with first location head cooperation use first constant head, one side meshing of first drive round gear has driven round gear, and the center department fixedly connected with long threaded rod of driven round gear bottom, the outer wall threaded connection of long threaded rod has long screw barrel, and the bottom of long screw barrel is provided with the extrusion seat that uses with pre-buried outer pipe box cooperation, extrusion seat is for inlaying with the injection head and establishes and be connected.

Preferably, one ends of the first three-way valve, the second three-way valve and the third three-way valve, which are close to the nitrogen tank, the liquid nitrogen tank and the water purifying tank, are respectively provided with a metering sensor, and the metering sensors are embedded with display panels.

Preferably, an electric heater is arranged at the top of the nitrogen tank, and a temperature sensor is embedded at one side of the nitrogen tank close to the electric heater.

Preferably, the periphery of the extrusion seat is uniformly and integrally formed with a convex sliding block, and guide rail grooves which are in sliding fit with the convex sliding block are vertically formed around the inner wall of the embedded outer pipe sleeve.

Preferably, the periphery of the pre-buried outer pipe sleeve is provided with jet outer holes in a penetrating mode, and the jet outer holes are distributed in a circumferential mode along the longitudinal axis of the pre-buried outer pipe sleeve.

Preferably, the outside fixedly connected with ear seat of sealed boss, and the inner chamber of ear seat inlays and is equipped with the thread bush, and the inner chamber threaded connection of thread bush has the positioning screw, three group positioning screw's top fixedly connected with screw up the head.

The use method of the liquid nitrogen fracturing device, according to any one of the above, comprises the following steps:

Firstly, inserting an embedded outer pipe sleeve into a well, forming an annular cavity for fracturing between the embedded outer pipe sleeve and the well, screwing positioning screws into threaded sleeves of three groups of lug seats by using tools respectively through three groups of screwing heads until the three groups of positioning screws are screwed into reserved spiral grooves at the edge of the well, plugging a sealing boss at the edge of the well and sealing the upper end of the annular cavity, controlling a double-head motor to open and drive a concave rod to rotate, driving a piston seat on a connecting rod arm to do reciprocating work in a cylinder barrel by the concave rod through a rotating sleeve, opening an air suction valve on an air suction port when the piston seat performs return suction in the cylinder barrel, closing an air discharge valve on an elbow, enabling external air to enter the cylinder barrel under the return suction force of the piston seat until the piston seat reaches the maximum return state in the cylinder barrel, opening the air discharge valve on the elbow, closing the air suction valve to stop the air inlet state when the piston seat performs process exhaust in the cylinder barrel, and forcing pressurized air generated in the cylinder barrel to be fed into a pressurizing tank through the elbow;

Step two, a first three-way valve on the nitrogen tank is opened, a second three-way valve and a third three-way valve are closed, nitrogen in the nitrogen tank is supplied into the first three-way valve, pressurized gas in the pressurized tank is supplied into the first three-way valve through a first pressurizing pipe to be converged with the nitrogen, quantitative treatment is carried out after metering and detection by a metering sensor on the first three-way valve, so that quantitative pressurized nitrogen is supplied into a telescopic pipe on the first supply pipe in advance, an electromagnetic valve on a jet head for conveying the pressurized nitrogen is correspondingly opened, the pressurized nitrogen is correspondingly supplied into an embedded outer pipe sleeve by the jet head, then the pressurized nitrogen is uniformly sprayed to an annular cavity inner wall rock soil layer reserved in a well to be fractured through an injection outer hole, and then the pressurized nitrogen is continuously pressurized and injected, so that the annular cavity inner wall rock soil layer reserved in the well is pre-cracked under the high pressure effect by means of the bottom of the well;

Step three, after a rock soil layer on the inner wall of the annular cavity reserved in a well is cracked under the action of high-pressure nitrogen, firstly controlling a double-headed motor to pause, then controlling a first electric push rod to open and drive a first positioning head to move upwards and clamp into a first positioning groove on a first driving round gear, then controlling the double-headed motor to continue to open and drive the first driving round gear to rotate through the first positioning head and the first positioning groove which are connected into a whole, driving a long threaded rod to rotate along with the first driving round gear through a driven round gear, driving a long threaded rod to move downwards along with the long threaded rod, and providing sliding limit compensation for a compression seat through a convex sliding block and a guide rail groove, driving the compression seat to downwards extrude the inner wall of an embedded outer pipe sleeve, simultaneously driving three telescopic pipes to downwards stretch through three groups of injection heads, driving the injection heads to downwards supply high-pressure nitrogen gas on the inner wall of the embedded outer pipe sleeve, driving extrusion to the inner wall space gas of the embedded outer pipe sleeve, and preventing the high-pressure nitrogen gas from flowing back into the embedded outer pipe sleeve through the injection outer hole, so that the high-pressure nitrogen pipe sleeve rapidly and effectively passes through the injection outer hole to uniformly spray the annular rock crack on the inner wall of the well to the annular cavity to the well, and the crack the required degree of the rock soil layer is increased;

After the high-pressure nitrogen finishes the crack fracturing operation on the rock and soil layer on the inner wall of the annular cavity in advance, a second three-way valve on the liquid nitrogen tank is firstly opened, liquid nitrogen in the liquid nitrogen tank with the first three-way valve and the third three-way valve is closed and is supplied into the second three-way valve, meanwhile, pressurized gas in the pressurizing tank is supplied into the second three-way valve through a second pressurizing pipe and is converged with the liquid nitrogen, and then quantitative treatment is carried out after the pressurized gas is metered and detected by a metering sensor on the second three-way valve, so that the quantitative pressurized liquid nitrogen is supplied into an expansion pipe on a second supply pipe in advance, and corresponds to opening an electromagnetic valve on an injection head for conveying the pressurized liquid nitrogen, the pressurized liquid nitrogen is correspondingly extruded and supplied into an embedded outer pipe sleeve by an injection head which moves downwards along with an extrusion seat, and is rapidly and effectively injected into the rock and soil layer on the inner wall of the annular cavity which finishes the pre-fracturing operation, so that the crack depth and the range of the area are further increased, and a complex crack network is formed in the rock and soil layer area on the inner wall of the annular cavity;

Step five, after the fracture network fracturing work of the annular cavity inner wall rock soil layer is completed by high-pressure liquid nitrogen, the first three-way valve on the nitrogen tank is opened again, the second three-way valve and the third three-way valve are closed, the electric heater is controlled to be opened in advance, nitrogen in the nitrogen tank is heated to form hot nitrogen, the heating temperature of the nitrogen in the nitrogen tank is monitored in real time by the temperature sensor, the hot nitrogen in the nitrogen tank is supplied into the first three-way valve, meanwhile, pressurized gas in the pressurized tank is supplied into the first three-way valve through the first pressurized pipe to be combined with the hot nitrogen, and then the pressurized hot nitrogen is metered and detected by the metering sensor on the first three-way valve and then is quantitatively treated, so that the quantitative pressurized hot nitrogen is sequentially supplied into the embedded outer pipe sleeve through the first supply pipe and the injection head, then is quickly and effectively injected into the fracture network area on the annular cavity inner wall rock soil layer through the injection outer hole, and the liquid nitrogen at the fracture network opening is pushed into the fracture opening and the inside, so that the liquid nitrogen is frozen and supported in the fracture opening and the fracture is deepened;

Step six, after hot nitrogen is jacked into the inside of a crack of liquid nitrogen at a crack network opening of a rock-soil layer on the inner wall of the annular cavity, a third three-way valve on the water purifying tank is firstly opened, the first three-way valve and the second three-way valve are closed, purified water in the water purifying tank is fed into the third three-way valve, pressurized gas in the pressurized tank is fed into the third three-way valve through a third pressurizing pipe to be converged with the purified water, and then quantitative treatment is carried out after the pressurized purified water is metered and detected by a metering sensor on the third three-way valve, so that the quantitative pressurized purified water is fed into a telescopic pipe on the third feeding pipe in advance, and an electromagnetic valve on a jet head for delivering the pressurized purified water is correspondingly opened, the pressurized purified water is correspondingly extruded and fed into an embedded outer pipe sleeve by a jet head which moves downwards along with a squeezing seat, and then is rapidly and effectively jetted into the annular cavity inner wall collapse rock-soil layer area for completing the jack-in crack operation of the liquid nitrogen, ice crystal is formed at the crack opening, and the crack opening of the crack network area is temporarily blocked by the purified water, so that the crack of the annular cavity inner wall rock-soil layer area is prevented from being retracted.

The beneficial effects of the application are as follows: when the rock and soil layer on the inner wall of the well is fractured, a unified driving source is provided by the double-headed motor of the primary pressurizing assembly, pressurizing pressure is supplied by the concave rod, the rotating sleeve, the connecting rod arm and the piston seat, after temporary storage by the pressurizing tank, the pressurizing source is respectively transported and supplied through the first pressurizing pipe, the second pressurizing pipe and the third pressurizing pipe, meanwhile, the first three-way valve, the second three-way valve and the third three-way valve of the fracturing assembly are used for carrying out sequential opening and closing control, nitrogen gas, liquid nitrogen and water purifying are provided by the nitrogen tank, the liquid nitrogen tank and the water purifying tank, the fracturing conducting materials are alternately used as the well inner wall rock and soil layer, water resource waste is reduced, the fracturing conducting materials are correspondingly sprayed to the rock and soil layer area on the inner wall of the well by the spraying heads on the three groups of telescopic pipes respectively, the complicated fracture network is formed in the area, the transformation range and the degree are enlarged, the fracture supporting is prevented from retracting, the first electric pushing rod of the secondary pressurizing assembly is used for adjusting the position between the first positioning head and the first positioning groove, the first positioning groove is used for adjusting the position, the first gear and the driven by the first driving gear and the driven gear to drive the driven round rod to reach the fracture surface, the fracture surface is not easy to form the fracture surface along with the fracture surface, and the fracture surface is rapidly driven by the compression surface of the underground compression surface, and the compression surface is formed to be in the fracture surface and the fracture surface, and the fracture surface is formed.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and other related drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a perspective structural initial state diagram of a liquid nitrogen fracturing device according to an embodiment of the present application;

FIG. 2 is a rear perspective view of a liquid nitrogen fracturing device according to an embodiment of the present application;

FIG. 3 is a perspective structural operational state diagram of a liquid nitrogen fracturing device according to an embodiment of the present application;

FIG. 4 is a partial cross-sectional view of a solid structure of a liquid nitrogen fracturing device in accordance with an embodiment of the present application;

FIG. 5 is a side cross-sectional view of a mount, cylinder barrel, primary compression assembly and fracturing assembly configuration in accordance with an embodiment of the present application;

FIG. 6 is a partial front view of the primary pressurization assembly and fracturing assembly configuration in accordance with an embodiment of the present application;

FIG. 7 is a partial rear view of a primary pressurization assembly and fracturing assembly configuration in accordance with an embodiment of the present application;

FIG. 8 is a side view of a pre-buried outer sleeve and secondary compression assembly structure in accordance with an embodiment of the present application;

FIG. 9 is a bottom view of a secondary pressurization assembly configuration in accordance with an embodiment of the present application;

FIG. 10 is a partial side view of a secondary pressurization assembly configuration in accordance with an embodiment of the present application;

FIG. 11 is a side view of an adjustment assembly structure according to an embodiment of the present application;

FIG. 12 is a partial cross-sectional view of a seal boss and pre-buried outer sleeve structure in accordance with an embodiment of the present application;

fig. 13 is an enlarged view of a portion of fig. 10 at a of a liquid nitrogen fracturing device in accordance with an embodiment of the present application.

Icon: 1. sealing the boss; 2. embedding an outer pipe sleeve; 3. a fixing frame; 4. a cylinder barrel; 5. a primary pressurization assembly; 51. a double-ended motor; 52. a concave bar; 53. a rotating sleeve; 54. a link arm; 55. a piston seat; 56. a pressurized tank; 57. a first pressurizing pipe; 58. a second pressurizing pipe; 59. a third pressurizing pipe; 6. a fracturing assembly; 61. a first three-way valve; 62. a second three-way valve; 63. a third three-way valve; 64. a nitrogen tank; 65. a liquid nitrogen tank; 66. a water purifying tank; 67. a first supply pipe; 68. a second supply pipe; 69. a third supply pipe; 610. a telescopic tube; 611. an ejection head; 7. a secondary pressurization assembly; 71. a first electric push rod; 72. a first positioning head; 73. a first driving circular gear; 74. a first positioning groove; 75. driven round gears; 76. an elongated threaded rod; 77. an elongated threaded cylinder; 78. extruding a base; 8. an adjustment assembly; 81. a second electric push rod; 82. a second positioning head; 83. a second driving circular gear; 84. a second positioning groove; 85. an annular gap; 86. pre-burying an inner pipe sleeve; 87. spraying an inner hole; 88. a gear ring; 89. a slide rail seat; 810. an annular slide rail; 9. a metering sensor; 10. an electric heater; 11. a temperature sensor; 12. a convex sliding block; 13. a guide rail groove; 14. spraying the outer hole; 15. an ear seat; 16. and positioning a screw.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, based on the embodiments of the application, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the application.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

As shown in fig. 1 to 13, a liquid nitrogen fracturing device according to an embodiment of the present application includes: the sealing boss 1 is fixedly connected with the embedded outer pipe sleeve 2 at the bottom of the sealing boss 1, the periphery of the embedded outer pipe sleeve 2 is provided with the jet outer holes 14 in a penetrating way, and the jet outer holes 14 are distributed in a circumferential shape along the longitudinal axis of the embedded outer pipe sleeve 2, so that uniform jet work of various fracturing conductors is facilitated, and the fracturing conductors can effectively reach the rock soil layer on the inner wall of the well;

The outer side of the sealing boss 1 is fixedly connected with an ear seat 15, a threaded sleeve is embedded in an inner cavity of the ear seat 15, a positioning screw 16 is connected with an inner cavity of the threaded sleeve in a threaded manner, the top of the three groups of positioning screws 16 is fixedly connected with a tightening head, and the sealing boss 1 and the upper end of a well are plugged to prevent leakage;

One side of the sealing boss 1 is provided with a fixing frame 3, one side of the fixing frame 3 far away from the sealing boss 1 is communicated with a cylinder barrel 4, an air suction port is formed in the cylinder barrel 4, an air suction valve is arranged at the air suction port, a primary pressurizing assembly 5 matched with the cylinder barrel 4 is arranged in the fixing frame 3, and a fracturing assembly 6 matched with the primary pressurizing assembly 5 and the embedded outer pipe sleeve 2 is arranged on the outer side of the sealing boss 1 to perform primary fracturing treatment on a rock soil layer on the inner wall of a well;

The inner cavity of the pre-buried outer pipe sleeve 2 is provided with a secondary pressurizing assembly 7 matched with the primary pressurizing assembly 5 for use, so that various fracturing conductors are driven and extruded, and the secondary fracturing effect of the rock and soil layers on the inner wall of the well is realized.

As shown in fig. 5 to 10, for the conventional well fracturing means, the most adopted fracturing conductive material is water, a large amount of water is needed during fracturing, so that a large amount of water resource is wasted, the fracturing cracks cannot be effectively supported and temporarily blocked, nitrogen, liquid nitrogen, hot nitrogen and water are alternately adopted as the fracturing conductive material, the well cannot be uniformly and effectively subjected to fracturing treatment in a manner of combining filling pressurization and driving extrusion, complex networking of the rock-soil layer cracks on the inner wall of the well is not realized, the opening and depth of the cracks are insufficient, the exploitation of underground oil gas is not facilitated, the first-stage pressurizing assembly 5 comprises a double-end motor 51, the double-end motor 51 is fixed on one side of the fixing frame 3 close to the sealing boss 1, and a uniform driving source is provided by the double-end motor 51;

And a concave rod 52 matched with the fixing frame 3 is fixedly connected to one output shaft of the double-headed motor 51, a rotating sleeve 53 is rotationally connected to the center of the concave rod 52, a connecting rod arm 54 is fixedly connected to the surface wall of the rotating sleeve 53, a piston seat 55 matched with the cylinder barrel 4 in a sliding manner is hinged to the other end of the connecting rod arm 54, an exhaust port of the cylinder barrel 4 is communicated with a pressurizing tank 56 through an elbow pipe, an exhaust valve is arranged on the elbow pipe, three exhaust ports of the pressurizing tank 56 are respectively communicated with a first pressurizing pipe 57, a second pressurizing pipe 58 and a third pressurizing pipe 59, pressurizing pressure is supplied by the concave rod 52, the rotating sleeve 53, the connecting rod arm 54 and the piston seat 55, after the pressurizing tank 56 is temporarily stored, the pressurizing pressure is transmitted and supplied through the first pressurizing pipe 57, the second pressurizing pipe 58 and the third pressurizing pipe 59, and the first pressurizing pipe 57, the second pressurizing pipe 58 and the third pressurizing pipe 59 are made of thickened steel pipes, and the compressive strength of the first pressurizing pipe 57, the second pressurizing pipe 58 and the third pressurizing pipe 59 are enhanced.

The fracturing assembly 6 comprises a first three-way valve 61, a second three-way valve 62 and a third three-way valve 63, wherein the first three-way valve 61, the second three-way valve 62 and the third three-way valve 63 are respectively communicated with one ends of a first pressurizing pipe 57, a second pressurizing pipe 58 and a third pressurizing pipe 59 far away from the pressurizing tank 56, the first three-way valve 61, the second three-way valve 62 and the third three-way valve 63 are used for carrying out sequential opening and closing control, one ends of the first three-way valve 61, the second three-way valve 62 and the third three-way valve 63 are respectively communicated with a nitrogen tank 64, a liquid nitrogen tank 65 and a water purifying tank 66, the nitrogen tank 64, the liquid nitrogen tank 65 and the water purifying tank 66 are used for providing nitrogen, liquid nitrogen and purified water for supplying alternately as fracturing conductivities of rock and soil layers in a well, so that the waste of water resources is reduced;

The other ends of the first three-way valve 61, the second three-way valve 62 and the third three-way valve 63 are respectively communicated with a first supply pipe 67, a second supply pipe 68 and a third supply pipe 69, the bottoms of the first supply pipe 67, the second supply pipe 68 and the third supply pipe 69 are communicated with telescopic pipes 610, the bottoms of the three groups of telescopic pipes 610 are communicated with injection heads 611, electromagnetic valves are arranged on the injection heads 611, and fracturing conductors are correspondingly injected to the region of a rock soil layer on the inner wall of a well through the injection heads 611 on the three groups of telescopic pipes 610 by the first supply pipe 67, the second supply pipe 68 and the third supply pipe 69, so that a complex fracture network is formed in the region, the transformation range and the degree of fracturing are enlarged, and the shrinkage collapse cannot occur due to insufficient fracture support;

One ends of the first three-way valve 61, the second three-way valve 62 and the third three-way valve 63, which are close to the nitrogen tank 64, the liquid nitrogen tank 65 and the water purifying tank 66, are respectively provided with a metering sensor 9, the nitrogen, hot nitrogen, liquid nitrogen and purified water flowing through the first three-way valve 61, the second three-way valve 62 and the third three-way valve 63 are quantitatively detected respectively, a display panel is embedded on the metering sensor 9, monitoring data of the metering sensor is displayed, the top of the nitrogen tank 64 is provided with an electric heater 10, one side of the nitrogen tank 64, which is close to the electric heater 10, is embedded with a temperature sensor 11, the nitrogen in the nitrogen tank 64 is heated to form hot nitrogen, the hot nitrogen can be heated to 25-35 ℃, and the temperature of the heated nitrogen in the nitrogen tank 64 is detected in real time by the temperature sensor 11.

The secondary pressurizing assembly 7 comprises a first electric push rod 71, the first electric push rod 71 is fixed at the top of the concave rod 52, a piston rod of the first electric push rod 71 is fixedly connected with a first positioning head 72, a first driving round gear 73 is arranged above the first positioning head 72, a first positioning groove 74 matched with the first positioning head 72 is formed in the center of the bottom of the first driving round gear 73, and the stroke position between the first positioning head 72 and the first positioning groove 74 is adjusted by the first electric push rod 71 of the secondary pressurizing assembly 7;

One side of the first driving round gear 73 is meshed with a driven round gear 75, the center of the bottom of the driven round gear 75 is fixedly connected with a long threaded rod 76, the outer wall of the long threaded rod 76 is in threaded connection with a long threaded cylinder 77, the bottom of the long threaded cylinder 77 is provided with an extrusion seat 78 matched with the embedded outer pipe sleeve 2, the extrusion seat 78 is embedded and connected with the injection head 611, the long threaded cylinder 77 and the extrusion seat 78 on the long threaded rod 76 are driven by the first driving round gear 73 and the driven round gear 75 to be pressed down along with the first driving round gear 73, and the alternately used fracturing conductors are driven downwards to be extruded, so that various fracturing conductors can quickly and effectively reach a rock-soil layer area on the inner wall of a well, and the fracture is prevented from forming in place, thereby being beneficial to underground oil and gas exploitation work;

The protruding slider 12 is evenly formed around the extrusion seat 78, and the guide rail grooves 13 which are in sliding fit with the protruding slider 12 are vertically formed around the inner wall of the embedded outer pipe sleeve 2, so that the extrusion seat 78 which is in lifting sliding can be subjected to sliding limiting, shaking and deflection during lifting of the extrusion seat 78 can be prevented, and the stability of the extrusion seat is improved.

As shown in fig. 11 and 12, during fracturing of the well by the fracturing conduction, a pipeline is basically embedded in the well and is sprayed to a rock soil layer on the inner wall of the well by an opened hole, the size and opening and closing of the hole formed in the embedded pipeline cannot be adjusted, so that the spraying amount of the fracturing conduction reaching the rock soil layer on the inner wall of the well is uneven, the spraying state is not easy to control, the fracturing conduction is easy to cause backflow, the fracturing conduction cannot be effectively acted on the rock soil layer area on the inner wall of the well, the maximum characteristic of the fracturing conduction cannot be exerted, the crack formation of the inner wall of the well is not facilitated, an adjusting component 8 matched with the embedded outer sleeve 2 is arranged in the sealing boss 1, the adjusting component 8 comprises a second electric push rod 81, the second electric push rod 81 is fixed on the other output shaft of the double-headed motor 51, a piston rod of the second electric push rod 81 is fixedly connected with a second positioning head 82, a second driving round gear 83 matched with the sealing boss 1 in a rotating mode is arranged below the second positioning head 82, the center of the top of the second driving round gear 83 is provided with a second positioning head 84 matched with the second positioning head, and the second positioning head 84 is connected with the second positioning head 84 in a rotating mode, and the second positioning head is adjusted by the second positioning head 84;

The inner cavity of the embedded outer sleeve 2 is provided with an annular gap 85 matched with the sealing boss 1, the annular gap 85 is rotationally connected with an embedded inner sleeve 86 matched with the sealing boss 1, the periphery of the embedded inner sleeve 86 is provided with an injection inner hole 87 matched with the injection outer hole 14, the top of the embedded inner sleeve 86 is fixedly connected with a gear ring 88, the periphery of the bottom of the gear ring 88 is fixedly connected with a slide rail seat 89, the top of the sealing boss 1 is provided with an annular slide rail 810 matched with the slide rail seat 89 in a sliding manner, the slide rail seat 89 and the annular slide rail 810 provide sliding support compensation for the gear ring 88, the second driving circular gear 83 drives the embedded inner sleeve 86 to finely rotate in the annular gap 85 through the gear ring 88, the size and the opening and closing adjusting effect of the injection outer hole 14 are realized by utilizing the staggered overlapping area between the injection inner hole 87 and the injection outer hole 14, the injection quantity of the conductive material reaches the rock soil layer of the inner wall, the conductive material is easy to control the injection state of the embedded inner wall rock soil layer, the conductive material is prevented from flowing back into the embedded outer sleeve 2 to cause raw material waste, the conductive material is enabled to effectively act on the inner wall of the well, the well is enabled to form the crack, and the characteristics of the well is favorable for the exploitation of the oil and gas can be well, and the oil and gas can exert the characteristics are well.

The use method of the liquid nitrogen fracturing device comprises the following steps of:

Firstly, inserting an embedded outer pipe sleeve 2 into a well, forming an annular cavity for fracturing between the embedded outer pipe sleeve 2 and the well, screwing positioning screws 16 into threaded sleeves of three groups of lug seats 15 by using tools through three groups of screwing heads respectively until the three groups of positioning screws 16 are screwed into reserved spiral grooves at the edge of the well, sealing a boss 1 at the edge of the well and sealing the upper end of the annular cavity, controlling a double-headed motor 51 to open and drive a concave rod 52 to rotate, driving a piston seat 55 on a connecting rod arm 54 by the concave rod 52 to do reciprocating work in a cylinder barrel 4 through a rotating sleeve 53, opening an air suction valve on an air suction port when the piston seat 55 performs return suction in the cylinder barrel 4, closing an air discharge valve on an elbow, allowing external air to enter the cylinder barrel 4 under the return suction force of the piston seat 55 until the piston seat 55 reaches the maximum return state in the cylinder barrel 4, opening the air discharge valve on the cylinder barrel 55, closing the air suction valve to stop the air inlet state, and forcing air generated in the cylinder barrel 4 to pass through the pressurizing pipe 56 by the extrusion force of the piston seat 55 when the piston seat 55 performs process exhaust in the cylinder barrel 4;

Step two, the first three-way valve 61 on the nitrogen tank 64 is opened again, the second three-way valve 62 and the third three-way valve 63 are closed, nitrogen in the nitrogen tank 64 is fed into the first three-way valve 61, meanwhile, pressurized gas in the pressurizing tank 56 is fed into the first three-way valve 61 through the first pressurizing pipe 57 to be converged with the nitrogen, then the metering sensor 9 on the first three-way valve 61 is used for metering and detecting the nitrogen, quantitative treatment is carried out, the quantitative pressurized nitrogen is fed into the telescopic pipe 610 on the first supply pipe 67 in advance, the electromagnetic valve on the injection head 611 for conveying the pressurized nitrogen is correspondingly opened, the pressurized nitrogen is fed into the embedded outer pipe sleeve 2 through the injection head 611, then the pressurized nitrogen is uniformly injected into the annular cavity inner wall rock soil layer reserved in the well to be fractured through the injection outer hole 14, and then the continuous pressurizing injection of the pressurized nitrogen is carried out under the high pressure action on the bottom of the well, so that the annular cavity inner wall rock soil layer reserved in the well is cracked in advance;

Step three, after the rock-soil layer on the inner wall of the annular cavity reserved in the well is cracked under the action of high-pressure nitrogen, the double-headed motor 51 is controlled to be suspended, the first electric push rod 71 is controlled to be started and drive the first positioning head 72 to move upwards and clamp into the first positioning groove 74 on the first driving round gear 73, the double-headed motor 51 is controlled to be continuously started and drive the first driving round gear 73 to rotate through the first positioning head 72 and the first positioning groove 74 which are connected into a whole, the first driving round gear 73 drives the long threaded rod 76 to rotate forwards along with the driven round gear 75, the long threaded rod 76 drives the long threaded cylinder 77 to move downwards along with the long threaded rod, the convex slide block 12 and the guide rail groove 13 provide sliding limiting compensation for the extrusion seat 78, the long thread cylinder 77 drives the extrusion seat 78 to extrude downwards on the inner wall of the pre-buried outer pipe sleeve 2, and simultaneously drives the three telescopic pipes 610 to stretch downwards through the three groups of injection heads 611, the extrusion seat 78 drives the injection heads 611 to supply high-pressure nitrogen downwards on the inner wall of the pre-buried outer pipe sleeve 2, and drives extrusion to the space gas on the inner wall of the pre-buried outer pipe sleeve 2, so that the high-pressure nitrogen is prevented from flowing back into the pre-buried outer pipe sleeve 2 through the injection outer holes 14, the high-pressure nitrogen is quickly and effectively uniformly injected to the rock-soil layer on the inner wall of the annular cavity reserved in the well to be fractured through the injection outer holes 14 on the pre-buried outer pipe sleeve 2, and the fracturing speed and the fracturing degree of the rock-soil layer cracks on the inner wall of the annular cavity are improved;

After the high-pressure nitrogen finishes the crack fracturing operation on the rock and soil layer on the inner wall of the annular cavity in advance, firstly opening a second three-way valve 62 on a liquid nitrogen tank 65, closing a first three-way valve 61 and a third three-way valve 63, feeding liquid nitrogen in the liquid nitrogen tank 65 into the second three-way valve 62, simultaneously feeding pressurized gas in a pressurizing tank 56 into the second three-way valve 62 through a second pressurizing pipe 58 to be converged with the liquid nitrogen, metering and detecting the pressurized gas by a metering sensor 9 on the second three-way valve 62, performing quantitative treatment, enabling the quantitative pressurized liquid nitrogen to be fed into a telescopic pipe 610 on a second supply pipe 68 in advance, correspondingly opening an electromagnetic valve on a jet head 611 for conveying the pressurized liquid nitrogen, correspondingly extruding the pressurized liquid nitrogen into a pre-buried outer pipe sleeve 2 by a jet outer hole 14, and then rapidly and effectively jetting the pressurized liquid nitrogen to the rock and soil layer on the inner wall of the annular cavity in advance, so that the crack depth and the range of the area of the annular cavity are further increased, and a complex crack net is formed in the rock and soil layer area on the inner wall of the annular cavity;

Step five, after the high-pressure liquid nitrogen completes the fracture network fracturing operation on the rock and soil layer on the inner wall of the annular cavity, the first three-way valve 61 on the nitrogen tank 64 is opened again, the second three-way valve 62 and the third three-way valve 63 are closed, the electric heater 10 is controlled to be opened in advance and heat the nitrogen in the nitrogen tank 64, hot nitrogen is formed, the temperature sensor 11 monitors the heating temperature of the nitrogen in the nitrogen tank 64 in real time, the hot nitrogen in the nitrogen tank 64 is supplied into the first three-way valve 61, meanwhile, the pressurized gas in the pressurized tank 56 is supplied into the first three-way valve 61 through the first pressurized pipe 57 to be combined with the hot nitrogen, and then the metering sensor 9 on the first three-way valve 61 is used for metering and detecting, and then quantitative treatment is carried out, so that the quantitative pressurized hot nitrogen sequentially passes through the first supply pipe 67 and the telescopic pipe 610 and is supplied into the pre-buried outer pipe sleeve 2 through the injection head 611, the hot nitrogen is quickly and effectively injected into the fracture network region on the rock and soil layer on the inner wall of the annular cavity through the injection outer hole 14, the liquid nitrogen is jacked into the fracture network region at the fracture network opening, the fracture and the fracture opening is supported and the fracture inside is deepened;

Step six, after hot nitrogen is jacked into the inside of cracks on the liquid nitrogen at the crack network opening of the rock-soil layer on the inner wall of the annular cavity, firstly, a third three-way valve 63 on a water purifying tank 66 is opened, the first three-way valve 61 and the second three-way valve 62 are closed, purified water in the water purifying tank 66 is fed into the third three-way valve 63, pressurized gas in the pressurizing tank 56 is fed into the third three-way valve 63 through a third pressurizing pipe 59 to be converged with the purified water, then the metered detection is carried out by a metering sensor 9 on the third three-way valve 63, quantitative pressurized purified water is fed into a telescopic pipe 610 on a third feeding pipe 69 in advance, an electromagnetic valve on a spraying head 611 for conveying the pressurized purified water is correspondingly opened, the pressurized purified water is correspondingly extruded and fed into an embedded outer pipe sleeve 2 by a spraying head 611 which moves downwards along with an extruding seat 78, then the pressurized purified water is rapidly and effectively sprayed into the rock-soil layer area on the annular cavity for finishing the jacking crack operation by an outer spraying hole 14, ice crystals are formed at the crack opening of the third pressurizing pipe, the crack network area is temporarily blocked by the crack opening of the liquid nitrogen, and the crack area is completely collapsed, and the work area of the annular crack-preventing the well is completed;

step seven, during this period, when the size and opening and closing state of the hole diameter of the injection outer hole 14 on the pre-buried outer sleeve 2 need to be adjusted, firstly, the double-headed motor 51 and the first electric push rod 71 are controlled to be closed, then, the second electric push rod 81 is controlled to be opened and drive the second positioning head 82 to move downwards and clamp into the second positioning groove 84 on the second driving circular gear 83, then, the double-headed motor 51 is controlled to be opened and drive the second driving circular gear 83 to rotate at a low speed through the second positioning head 82 and the second positioning groove 84 which are connected into a whole, the sliding support compensation is provided for the gear ring 88 by the sliding rail seat 89 and the annular sliding rail 810, then, the second driving circular gear 83 drives the pre-buried inner sleeve 86 to slowly rotate in the annular gap 85 through the gear ring 88, according to the hole diameter adjustment requirement of the injection outer hole 14, the pre-buried inner sleeve 86 drives the injection inner hole 87 to be staggered with the pre-buried outer hole 14, if the overlapping area of the injection inner hole 87 and the injection outer hole 14 is large, the hole diameter of the injection outer hole 14 is large, otherwise, the overlapping area of the injection outer hole diameter of the injection outer hole 14 is large, if the overlapping area of the injection inner hole 87 and the injection outer hole 14 is small, and if the overlapping the hole diameter of the injection inner hole 87 and the injection outer hole 14 is small, and the injection outer hole 14 is completely opened and completely, and the opening and completely and opened and the injection outer hole 14 is completely is closed, and opened and the nitrogen is completely, and opened and the hole 14 and when the hole is completely and opened and completely and the hole is opened and opened.

It should be noted that, specific model specifications of the double-headed motor 51, the first electric push rod 71, the second electric push rod 81 and the electric heater 10 need to be determined by selecting a model according to actual specifications of the device, and a specific model selection calculation method adopts the prior art, so that detailed descriptions thereof are omitted.

The power supply of the double-headed motor 51, the first electric push rod 71, the second electric push rod 81, the electric heater 10, and various sensors and the principle thereof will be apparent to those skilled in the art, and will not be described in detail herein.

The above embodiments of the present application are only examples, and are not intended to limit the scope of the present application, and various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

The foregoing is merely illustrative embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about variations or substitutions within the technical scope of the present application, and the application should be covered. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims (10)

1. Liquid nitrogen fracturing device, its characterized in that includes: the sealing boss (1), the bottom of the sealing boss (1) is fixedly connected with an embedded outer pipe sleeve (2);

One side of the sealing boss (1) is provided with a fixing frame (3), one side of the fixing frame (3) far away from the sealing boss (1) is communicated with a cylinder barrel (4), a primary pressurizing assembly (5) is arranged in the fixing frame (3), and the outer side of the sealing boss (1) is provided with a fracturing assembly (6);

the inner cavity of the pre-buried outer pipe sleeve (2) is provided with a secondary pressurizing assembly (7).

2. The liquid nitrogen fracturing device according to claim 1, wherein the primary pressurizing assembly (5) comprises a double-headed motor (51), the double-headed motor (51) is fixed on one side, close to the sealing boss (1), of the fixing frame (3), a concave rod (52) matched with the fixing frame (3) for use is fixedly connected to one output shaft of the double-headed motor (51), a rotating sleeve (53) is rotatably connected to the center of the concave rod (52), a connecting rod arm (54) is fixedly connected to the surface wall of the rotating sleeve (53), a piston seat (55) in sliding fit with the cylinder barrel (4) is hinged to the other end of the connecting rod arm (54), a pressurizing tank (56) is communicated with an exhaust valve through an elbow, and a first pressurizing pipe (57), a second pressurizing pipe (58) and a third pressurizing pipe (59) are respectively communicated with three exhaust ports of the pressurizing tank (56).

3. The liquid nitrogen fracturing device according to claim 2, wherein the fracturing assembly (6) comprises a first three-way valve (61), a second three-way valve (62) and a third three-way valve (63), the first three-way valve (61), the second three-way valve (62) and the third three-way valve (63) are respectively communicated with one end of a first pressurizing pipe (57), one end of a second pressurizing pipe (58) and one end of a third pressurizing pipe (59) far away from the pressurizing tank (56), one end of the first three-way valve (61), one end of the second three-way valve (62) and one end of the third three-way valve (63) are respectively communicated with a nitrogen tank (64), a liquid nitrogen tank (65) and a water purifying tank (66), the other ends of the first three-way valve (61), the second three-way valve (62) and the third three-way valve (63) are respectively communicated with a first supplying pipe (67), a second supplying pipe (68) and a third supplying pipe (69), the bottom ends of the first supplying pipe (67), the second supplying pipe (68) and the third supplying pipe (69) are communicated with one end of the telescoping pipe (610), one end of the three groups is communicated with the telescoping pipe (610), and the bottom ends of the telescoping pipe (611) are communicated with the jetting head (611).

4. The liquid nitrogen fracturing device according to claim 3, wherein the secondary pressurizing assembly (7) comprises a first electric push rod (71), the first electric push rod (71) is fixed at the top of the concave rod (52), a piston rod of the first electric push rod (71) is fixedly connected with a first positioning head (72), a first driving round gear (73) is arranged above the first positioning head (72), a first positioning groove (74) matched with the first positioning head (72) is formed in the center of the bottom of the first driving round gear (73), a driven round gear (75) is meshed with one side of the first driving round gear (73), an elongated threaded rod (76) is fixedly connected to the center of the bottom of the driven round gear (75), an elongated threaded rod (77) is connected to the outer wall of the elongated threaded rod in a threaded mode, a pressing seat (78) matched with the embedded outer sleeve (2) is arranged at the bottom of the elongated threaded rod (76), and the pressing seat (78) is embedded with the spraying head (611).

5. A liquid nitrogen fracturing device according to claim 3, characterized in that one end of the first three-way valve (61), the second three-way valve (62) and the third three-way valve (63) close to the nitrogen tank (64), the liquid nitrogen tank (65) and the water purifying tank (66) is respectively provided with a metering sensor (9), and the metering sensor (9) is embedded with a display panel.

6. A liquid nitrogen fracturing device according to claim 3, characterized in that an electric heater (10) is arranged at the top of the nitrogen tank (64), and a temperature sensor (11) is embedded at one side of the nitrogen tank (64) close to the electric heater (10).

7. The liquid nitrogen fracturing device according to claim 4, wherein the periphery of the extrusion seat (78) is integrally formed with a convex sliding block (12), and the periphery of the inner wall of the pre-buried outer pipe sleeve (2) is vertically provided with guide rail grooves (13) which are in sliding fit with the convex sliding block (12).

8. The liquid nitrogen fracturing device according to claim 1, wherein the periphery of the pre-buried outer pipe sleeve (2) is provided with jet outer holes (14) in a penetrating manner, and the jet outer holes (14) are distributed in a circumferential manner along the longitudinal axis of the pre-buried outer pipe sleeve (2).

9. The liquid nitrogen fracturing device according to claim 1, wherein an ear seat (15) is fixedly connected to the outer side of the sealing boss (1), a threaded sleeve is embedded in an inner cavity of the ear seat (15), a positioning screw (16) is connected to an inner cavity of the threaded sleeve in a threaded manner, and screwing heads are fixedly connected to the tops of the three groups of positioning screws (16).

10. Use of a liquid nitrogen fracturing device according to any of the preceding claims 1-9, characterized in that it comprises the following steps:

Firstly, inserting an embedded outer pipe sleeve (2) into a well, forming an annular cavity for fracturing between the embedded outer pipe sleeve (2) and the well, screwing a positioning screw rod (16) into threaded sleeves of three groups of lug seats (15) by using a tool through three groups of screwing heads respectively until the three groups of positioning screw rods (16) are screwed into reserved screw grooves at the edge of the well, sealing a boss (1) at the edge of the well and sealing the upper end of the annular cavity, controlling a double-headed motor (51) to open and drive a concave rod (52) to rotate, driving a piston seat (55) on a connecting rod arm (54) to do reciprocating work in a cylinder barrel (4) through a rotating sleeve (53), opening an exhaust valve on an air suction port when the piston seat (55) performs return suction in the cylinder barrel (4), closing an exhaust valve on the elbow, enabling external air to enter the cylinder barrel (4) under the return suction action of the piston seat (55) until the piston seat (55) reaches the maximum state in the cylinder barrel (4), and closing the exhaust valve when the piston seat (55) is pressed in the cylinder barrel (4) to perform compression action in the elbow, and pressurizing action force is generated in the cylinder barrel (4;

Step two, a first three-way valve (61) on a nitrogen tank (64) is opened again, a second three-way valve (62) and a third three-way valve (63) are closed, nitrogen in the nitrogen tank (64) is fed into the first three-way valve (61), pressurized gas in a pressurizing tank (56) is fed into the first three-way valve (61) through a first pressurizing pipe (57) to be converged with the nitrogen, quantitative treatment is carried out after metering detection by a metering sensor (9) on the first three-way valve (61), so that quantitative pressurized nitrogen is fed into a telescopic pipe (610) on a first supply pipe (67) in advance, an electromagnetic valve on an injection head (611) for conveying the pressurized nitrogen is correspondingly opened, the pressurized nitrogen is fed into an embedded outer pipe sleeve (2) through the injection head (611) and is uniformly injected into an annular cavity inner wall rock soil layer reserved in a well to be fractured, and then the annular cavity inner wall rock reserved in the well is continuously pressurized and injected under the action of high pressure by means of the bottom of the well;

Step three, after the rock soil layer on the inner wall of the annular cavity reserved in the well is cracked under the action of high-pressure nitrogen, the double-headed motor (51) is controlled to be suspended, the first electric push rod (71) is controlled to be started and drive the first positioning head (72) to move upwards and clamp into the first positioning groove (74) on the first driving round gear (73), the double-headed motor (51) is controlled to be continuously started and drive the first driving round gear (73) to rotate through the first positioning head (72) and the first positioning groove (74) which are connected into a whole, the first driving round gear (73) drives the long threaded rod (76) to rotate positively through the driven round gear (75), the long threaded rod (76) drives the long threaded cylinder (77) to move downwards along with the long threaded cylinder, the convex sliding block (12) and the guide rail groove (13) provide sliding limit compensation for the extrusion seat (78), the long threaded cylinder (77) drives the extrusion seat (78) to extrude downwards on the inner wall of the embedded outer pipe sleeve (2), simultaneously three telescopic pipes (610) are driven to stretch downwards through three groups of injection heads (611), the extrusion seat (78) drives the injection heads (611) to supply high-pressure nitrogen downwards on the inner wall of the embedded outer pipe sleeve (2), drives gas on the inner wall space of the embedded outer pipe sleeve (2) to extrude, and also prevents the high-pressure nitrogen from flowing back into the embedded outer pipe sleeve (2) through the injection outer holes (14), the high-pressure nitrogen is quickly and effectively uniformly sprayed to the rock-soil layer on the inner wall of the annular cavity reserved in the well to be fractured through the spraying outer holes (14) on the pre-buried outer pipe sleeve (2), so that the fracturing speed and the fracturing degree of the rock-soil layer cracks on the inner wall of the annular cavity are improved;

After the high-pressure nitrogen finishes the crack fracturing operation on the rock and soil layer on the inner wall of the annular cavity in advance, a second three-way valve (62) on a liquid nitrogen tank (65) is opened, a first three-way valve (61) and a third three-way valve (63) are closed, liquid nitrogen in the liquid nitrogen tank (65) is fed into the second three-way valve (62), pressurized gas in a pressurizing tank (56) is fed into the second three-way valve (62) through a second pressurizing pipe (58), and is metered and detected by a metering sensor (9) on the second three-way valve (62) and then subjected to quantitative treatment, so that the quantitative pressurized liquid nitrogen is fed into a telescopic pipe (610) on a second supply pipe (68) in advance, and an electromagnetic valve on a jet head (611) for conveying the pressurized liquid nitrogen is correspondingly opened, the pressurized liquid nitrogen is correspondingly extruded and fed into an embedded outer pipe sleeve (2) through a jet outer hole (14) in a pressing mode, and is rapidly and effectively jetted to the inner wall of the annular cavity to complete the crack fracturing operation, so that the quantitative pressurized liquid nitrogen is fed into a telescopic pipe (610) on the telescopic pipe (611) on the basis, and the electromagnetic valve is correspondingly opened, and the depth of the annular cavity crack and the soil layer is further formed in the area of the annular cavity;

Step five, after the fracture network fracturing operation of the rock and soil layer on the inner wall of the annular cavity is completed by high-pressure liquid nitrogen, in the same step two, a first three-way valve (61) on a nitrogen tank (64) is opened again, a second three-way valve (62) and a third three-way valve (63) are closed, an electric heater (10) is controlled to be opened in advance, nitrogen in the nitrogen tank (64) is heated to form hot nitrogen, the heating temperature of the nitrogen in the nitrogen tank (64) is monitored in real time by a temperature sensor (11), then the hot nitrogen in the nitrogen tank (64) is fed into the first three-way valve (61), meanwhile, pressurized gas in a pressurizing tank (56) is fed into the first three-way valve (61) through a first pressurizing pipe (57) to be combined with the hot nitrogen, and then quantitative treatment is carried out after the metering detection by a metering sensor (9) on the first three-way valve (61), so that the quantitative pressurized hot nitrogen sequentially passes through a first supply pipe (67) and a telescopic pipe (610) and is fed into an outer pipe (2) by a jetting head (11), and then the nitrogen is jetted into an outer pipe (14) to be effectively supported by the annular cavity to the fracture network, and the fracture network is opened in a deep-side, and the fracture network is effectively opened by the fracture network is further processed;

Step six, after hot nitrogen is jacked into cracks at the position of a crack network of the rock soil layer on the inner wall of the annular cavity, a third three-way valve (63) on a water purifying tank (66) is firstly opened, the first three-way valve (61) and the second three-way valve (62) are closed, purified water in the water purifying tank (66) is fed into the third three-way valve (63), meanwhile, pressurized gas in the pressurized tank (56) is fed into the third three-way valve (63) through a third pressurizing pipe (59) to be converged with the purified water, quantitative treatment is carried out after the metering detection by a metering sensor (9) on the third three-way valve (63), so that quantitative pressurized purified water is fed into a telescopic pipe (610) on a third supply pipe (69) in advance, and the electromagnetic valve on the injection head (611) for conveying pressurized purified water is correspondingly opened, the pressurized purified water is correspondingly extruded and fed into the embedded outer pipe sleeve (2) by the injection head (611) which moves downwards along with the extrusion seat (78), and then is rapidly and effectively injected to the annular cavity inner wall rock soil layer area for completing the operation of jacking the liquid nitrogen into the crack by the injection outer hole (14), so that the purified water and the liquid nitrogen form ice crystals at the crack opening, the crack opening of the crack network area is temporarily blocked to prevent the crack from retracting and collapsing, and the fracturing work of the annular cavity inner wall rock soil layer area of the well is completed.