A nitrogen foam generator for oil well fracturing

Abstract

The present invention discloses a nitrogen foam generator for oil well fracturing, which relates to the technical field of oil well fracturing, and comprises a mixing assembly, a fracturing head assembly being installed at the bottom of the mixing assembly, a pushing assembly being provided inside the fracturing head assembly, a shaking assembly being provided on the top of the pushing assembly, and an injection assembly being provided outside the pushing assembly. In the present invention, the leakage of fracturing fluid into the gap between the fracturing head and the formation wall can be effectively prevented, which not only improves the fracturing effect, but also avoids the safety hazard of abnormal local pressure in the formation caused by nitrogen foam leaking into the gap between the fracturing head and the formation wall. At the same time, the injection head will be in a state of impact and rotation after contacting the formation wall, and its conical end head can effectively penetrate the formation wall for fracturing operations, thereby avoiding leakage of nitrogen foam, further improving the fracturing effect, and improving the quality of nitrogen foam and the fracturing effect.

Description

Technical Field

[0001] The present invention relates to the technical field of oil well fracturing, in particular to a nitrogen foam generator for oil well fracturing. Background Art

[0002] In oil well fracturing operations in petroleum extraction, the basic principle of nitrogen foam fracturing technology is to mix nitrogen with fracturing fluid containing a foaming agent to form a stable nitrogen foam. The nitrogen is dispersed in the fracturing fluid in the form of tiny bubbles, which greatly reduces the liquid density, reduces the liquid column pressure, and reduces damage to the formation. The compressibility of nitrogen is conducive to the rapid return of foam after fracturing, reduces residue, and maintains the permeability of the formation, thereby increasing oil well production and mining efficiency. Its advantages are prominent in the mining of complex formations.

[0003] Oil well fracturing is a key technical means of increasing oil and gas well production. However, when a conventional nitrogen foam generator fracturing head is inserted into a wellbore for fracturing, a gap forms between the head and the formation wall. This gap directly causes some nitrogen foam to leak into the gap during the fracturing process, preventing it from effectively fracturing the formation and thus affecting the fracturing effect. Therefore, a nitrogen foam generator for oil well fracturing has been proposed to address the issues raised in the aforementioned background technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a nitrogen foam generator for oil well fracturing, so as to solve the problem proposed in the above-mentioned background art that a certain gap will be left between the fracturing head and the formation wall after the fracturing head is sent into the wellbore. This gap directly causes a part of the nitrogen foam to leak into the gap during the fracturing process, and the nitrogen foam cannot effectively act on the formation for fracturing, thereby affecting the fracturing effect.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: A nitrogen foam generator for oil well fracturing, comprising a mixing assembly, a fracturing head assembly being installed at the bottom of the mixing assembly, a pushing assembly being provided inside the fracturing head assembly, a shaking assembly being provided on the top of the pushing assembly, and an injection assembly being provided outside the pushing assembly, the mixing assembly comprising a mixing shell, the fracturing head assembly comprising a fracturing head outer shell, the shaking assembly comprising a connecting column, the pushing assembly comprising a baffle, a snowflake block being fixedly connected to the bottom of the baffle, six first guide grooves being equidistantly provided near the middle position of the top of the snowflake block, six second guide grooves being equidistantly provided on the outer surface of the snowflake block, the first guide grooves and the second guide grooves being connected to each other, the number of the injection assemblies being set to six, each comprising a first slider and a second slider, the first slider being slidably embedded in the first guide groove, the second slider being slidably embedded in the second guide groove, the outer surface of the second slider being provided with a bearing, and the outer surface of the bearing being provided with an injection head extending outward.

[0006] Preferably, an air inlet and a liquid inlet are provided at the top of the mixing shell, a spiral mixing channel is provided inside the mixing shell, and an upwardly recessed bubble discharge port is provided at the bottom of the mixing shell. The air inlet and the liquid inlet are both communicated with the upper opening of the spiral mixing channel, and the lower opening of the spiral mixing channel is communicated with the bubble discharge port. An air inlet pipe is threadedly connected between the inner surface walls of the air inlet, a liquid inlet pipe is threadedly connected between the inner surface walls of the liquid inlet, and a joint is fixedly connected to the bottom end of the mixing shell.

[0007] By adopting the above technical solution, when in use, the device is sent into the specified depth of the oil well through the pipeline, and then fracturing fluid is quantitatively pumped into the liquid inlet through the pipeline, and nitrogen is pumped into the air inlet pipe. After the nitrogen and fracturing fluid pass through the air inlet and liquid inlet areas, they collide and complete preliminary mixing. Then, under the action of pressure, the two enter the spiral mixing channel and are transported to the bubble discharge port. During the process, they rotate in the spiral mixing channel and continuously collide, shear and knead with each other, thereby forming nitrogen foam, which is then transported downward in a large volume through the bubble discharge port with a larger diameter.

[0008] Preferably, the outer surface of the joint is threadedly connected to the inner wall of the fracturing head shell, and the bottom of the mixing shell is in conflict with the top of the fracturing head shell.

[0009] By adopting the above technical solution, the joint is mainly used to connect the mixing shell and the fracturing head outer shell.

[0010] Preferably, a barrier ring is fixedly connected to the middle of the inner surface wall of the fracturing head shell, the top of the barrier ring is concave, and a plurality of guide fins are equidistantly arranged on the top of the barrier ring. The inner aperture of the barrier ring is smaller than the diameter of the spoiler.

[0011] By adopting the above technical solution, the top of the barrier ring is concave, and the concave part is arc-shaped, which plays a role in guiding the nitrogen foam, so that when it impacts the top of the barrier ring, it will flow along the arc surface toward the lower center. The guide fins are arc-shaped, and the nitrogen foam will form a vortex in the process of flowing from the top of the barrier ring to the center, and rush toward the circular filter at a certain angle and speed. This dynamic impact makes it easier for the bubbles to be divided into small bubbles by the circular filter, thereby improving the subsequent fracturing effect.

[0012] Preferably, a sliding groove is provided at the bottom of the snowflake block, a sliding sleeve is slidably provided on the inner surface wall of the sliding groove, the bottom of the sliding sleeve is fixedly connected to the center of the inner bottom of the fracturing head shell, a strong spring is fixedly connected between the inner bottom of the sliding sleeve and the inner top of the sliding groove, and the top of the spoiler and the bottom of the barrier ring are in conflict.

[0013] By adopting the above technical solution, the sliding sleeve guides the snowflake block so that it can only move in the vertical direction. When the fracturing operation is stopped, the strong spring rebound will push the snowflake block to move upward and reset.

[0014] Preferably, an injection channel is provided at the bottom of the second slider and the other end of the injection channel is connected to the interior of the injection head, the outer surface of the injection head is threaded and penetrates the outer surface of the fracturing head shell, and an inner shrinkage sleeve is fixedly connected to a position near the middle between the inner surface walls of the injection head. The outer surface of the first slider close to the injection head is rotatably connected to a connecting rod, the outer surface of the connecting rod penetrates the outer surface of the second slider, and the end of the connecting rod away from the first slider is fixedly connected to a plug, the inner diameter of the inner shrinkage sleeve is smaller than the outer diameter of the plug, and the inner shrinkage sleeve and the outer surface of the plug are in contact, the first guide groove is vertically arranged, and the second guide groove is inclined.

[0015] By adopting the above technical solution, the inclined second guide groove will generate an oblique thrust on the second slider, and the vertical first guide groove will not generate an oblique thrust on the first slider. At the same time, the injection head is limited by the guide sleeve and will not move up and down. Therefore, the second slider subjected to the oblique thrust will laterally push the end of the injection head to slide outside the fracturing head shell. During this process, the retracted sleeve inside the injection head will follow the movement, while the plug connected to the first slider through the connecting rod will remain in a relatively stationary position. Therefore, the retracted sleeve and the plug will separate, thereby forming a passage state inside the injection head. Subsequently, under the action of pressure, the nitrogen foam in the fracturing head shell will enter the injection head from the injection channel under the second slider and then be injected into the wellbore formation wall to complete the fracturing operation.

[0016] Preferably, the top of the connecting column is fixedly connected to a driving blade, the bottom of the connecting column is fixedly connected to a connecting sleeve, a circular seat is provided between the inner surface walls of the connecting sleeve near the bottom, and the circular seat is fixedly connected to the top center of the spoiler.

[0017] By adopting the above technical solution, the flow energy generated when the nitrogen foam discharged from the mixing shell enters the outer shell of the fracturing head will act on the driving blade and cause it to rotate. When the driving blade rotates, it will drive the connecting sleeve to rotate.

[0018] Preferably, a wave groove is provided on the outer surface of the circular seat, and four protrusions are fixedly connected to the inner wall of the connecting sleeve. The four protrusions are distributed in a ring on the outer side of the circular seat, and one end of the opposite side of the four protrusions is slidably embedded in the lowest point of the inner wall of the wave groove.

[0019] By adopting the above technical solution, the wave groove is composed of four V-shaped grooves connected end to end. When the connecting sleeve rotates, the protrusion on the inner wall will slide in the wave groove on the surface of the circular seat. There is a height difference in the wave groove path. Therefore, during the rotation of the connecting sleeve, the connecting column and the driving blade will continue to move up and down rapidly.

[0020] Preferably, a plurality of functional plates are fixedly connected to the outer surface of the connecting column at equal intervals, and the functional plates are higher than the barrier ring.

[0021] By adopting the above technical solution, the functional plate is composed of a hard outer frame and an inner filter screen. When it rotates with the connecting column, it has the effect of mixing, stirring and shearing the nitrogen foam flowing through.

[0022] Preferably, a circular filter is fixedly connected between the inner surface walls of the barrier ring, the circular filter is annular, and the inner surface wall of the circular filter fits the outer surface of the connecting column, and six guide sleeves are fixedly connected to the inner surface wall of the fracturing head shell at equal intervals, and the guide sleeves and the injection head are threadedly connected.

[0023] By adopting the above technical solution, the guide sleeve serves to limit the injection head, thereby improving the stability of the injection head during lateral movement. The two are connected by threads, so when the injection head moves inside the guide sleeve, a rotation effect is generated.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. When the present invention is used, a mixing component is provided to mix the pumped nitrogen and fracturing fluid to form nitrogen foam for fracturing. Under the action of pressure, the pushing component is triggered and then cooperated with the injection component to drive the injection head to press tightly against the formation wall to inject nitrogen foam. As the fracturing operation continues, the injection head will gradually penetrate into the formation wall to perform fracturing operations, which can effectively prevent the fracturing fluid from leaking into the gap between the fracturing head and the formation wall. This not only improves the fracturing effect, but also avoids the safety hazard of abnormal local pressure in the formation caused by nitrogen foam leaking into the gap between the fracturing head and the formation wall.

[0026] 2. When the present invention is used, the flow energy generated when the nitrogen foam discharged from the mixing shell enters the outer shell of the fracturing head will act on the driving blade and rotate it. At the same time, with the cooperation of the connecting column, connecting sleeve, convex head, circular seat and wave groove, the baffle can be made to shake up and down at a high frequency in a small range, thereby causing the injection head to shake laterally. At the same time, since the injection head thread passes through the guide sleeve and the fracturing head outer shell, it will continuously rotate slightly forward and backward during the lateral shaking due to the action of the thread. Therefore, after the injection head contacts the formation wall, it will be in a state of impact and rotation. Its conical end can effectively penetrate the formation wall for fracturing operation, thereby avoiding leakage of nitrogen foam and further improving the fracturing effect.

[0027] 3. When the present invention is used, when the driving blade rotates, the connecting column will drive the functional plate on the surface to rotate rapidly, thereby further mixing the nitrogen foam passing through and preventing bubble aggregation. The middle of the functional plate is in the shape of a filter, which will generate physical shear force on the nitrogen foam passing through while stirring, thereby forming smaller bubbles. The circular filter further refines the bubbles, thereby improving the quality of the nitrogen foam and the fracturing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a three-dimensional diagram of a nitrogen foam generator for oil well fracturing according to the present invention;

[0029] Figure 2 This is a cross-sectional view of a nitrogen foam generator for oil well fracturing according to the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of a mixing assembly of a nitrogen foam generator for oil well fracturing according to the present invention;

[0031] Figure 4 This is a partial structural cross-sectional view of a nitrogen foam generator for oil well fracturing according to the present invention;

[0032] Figure 5 This is a schematic structural diagram of a fracturing head assembly of a nitrogen foam generator for oil well fracturing according to the present invention;

[0033] Figure 6 This is a schematic diagram of the connections between a shaking assembly, a pushing assembly, and an injection assembly of a nitrogen foam generator for oil well fracturing according to the present invention;

[0034] Figure 7 This is a schematic structural diagram of a shaking assembly of a nitrogen foam generator for oil well fracturing according to the present invention;

[0035] Figure 8 This is a schematic structural diagram of a pushing component of a nitrogen foam generator for oil well fracturing according to the present invention;

[0036] Figure 9 This is a schematic structural diagram of an injection assembly of a nitrogen foam generator for oil well fracturing according to the present invention;

[0037] Figure 10 This is a schematic diagram of the lifting of the snowflake block of a nitrogen foam generator for oil well fracturing according to the present invention.

[0038] Figure: 1. Mixing assembly; 101. Mixing shell; 102. Air inlet; 103. Liquid inlet; 104. Air inlet pipe; 105. Liquid inlet pipe; 106. Spiral mixing channel; 107. Bubble outlet; 108. Connector; 2. Fracturing head assembly; 201. Fracturing head housing; 202. Blocking ring; 203. Guide fin; 204. Circular filter; 205. Guide sleeve; 3. Shaking assembly; 301. Connecting column; 302. Drive blade; 303. Function board; 304. Connecting Sleeve; 305, convex head; 306, circular seat; 307, wave groove; 4, pushing assembly; 401, spoiler; 402, snowflake block; 403, first guide groove; 404, second guide groove; 405, sliding groove; 406, sliding sleeve; 407, strong spring; 5, injection assembly; 501, first slider; 502, second slider; 503, bearing; 504, injection head; 505, injection channel; 506, retracted sleeve; 507, connecting rod; 508, plug. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the implementation regulations described are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] Example 1: Please refer to Figures 1-10 As shown, the present invention provides a technical solution: a nitrogen foam generator for oil well fracturing, comprising a mixing component 1, a fracturing head component 2 is installed at the bottom of the mixing component 1, a pushing component 4 is arranged inside the fracturing head component 2, a shaking component 3 is arranged on the top of the pushing component 4, and an injection component 5 is arranged outside the pushing component 4. The mixing component 1 includes a mixing shell 101, the fracturing head component 2 includes a fracturing head shell 201, the shaking component 3 includes a connecting column 301, the pushing component 4 includes a baffle 401, the bottom of the baffle 401 is fixedly connected to a snowflake block 402, and the top of the snowflake block 402 is fixedly connected to the snowflake block 402. Six first guide grooves 403 are equidistantly provided near the middle position of the snowflake block 402, and six second guide grooves 404 are equidistantly provided on the outer surface of the snowflake block 402. The first guide grooves 403 and the second guide grooves 404 are connected. The number of injection assemblies 5 is set to six, each including a first slider 501 and a second slider 502. The first slider 501 is slidably embedded in the inside of the first guide groove 403, and the second slider 502 is slidably embedded in the inside of the second guide groove 404. A bearing 503 is installed on the outer surface of the second slider 502, and a spray head 504 extending outward is installed on the outer surface of the bearing 503.

[0041] An air inlet 102 and a liquid inlet 103 are provided at the top of the mixing shell 101, a spiral mixing channel 106 is provided inside the mixing shell 101, and an upwardly recessed bubble discharge port 107 is provided at the bottom of the mixing shell 101. The air inlet 102 and the liquid inlet 103 are both communicated with the upper opening of the spiral mixing channel 106, and the lower opening of the spiral mixing channel 106 is communicated with the bubble discharge port 107. An air inlet pipe 104 is threadedly connected between the inner surface walls of the air inlet 102, and a liquid inlet pipe 105 is threadedly connected between the inner surface walls of the liquid inlet 103. A joint 108 is fixedly connected to the bottom end of the mixing shell 101. During use, the device is sent to the specified depth of the oil well through a pipeline, and then fracturing fluid is quantitatively pumped into the liquid inlet 103 through the pipeline, and nitrogen is pumped into the air inlet pipe 104. After the nitrogen and fracturing fluid pass through the air inlet 102 and the liquid inlet 103, they collide and complete preliminary mixing. Then, under the action of pressure, the two enter the spiral spiral mixing channel 106 and are transported to the bubble discharge port 107. During the process, they will rotate in the spiral mixing channel 106 and continuously collide, shear and rub with each other, thereby forming nitrogen foam, which is then transported downward in a large volume through the bubble discharge port 107 with a larger diameter.

[0042] The outer surface of the joint 108 is threadedly connected to the inner wall of the fracturing head shell 201, and the bottom of the mixing shell 101 is in conflict with the top of the fracturing head shell 201. The mixing shell 101 and the fracturing head shell 201 are threadedly connected through the joint 108 and can be disassembled. After installation, the bottom of the mixing shell 101 and the top of the fracturing head shell 201 are in close conflict, and a sealing ring is added between the two to ensure sealing.

[0043] A barrier ring 202 is fixedly connected to a position near the middle between the inner surface walls of the fracturing head shell 201. The top of the barrier ring 202 is concave, and a plurality of guide fins 203 are equidistantly arranged on the top of the barrier ring 202. The inner aperture of the barrier ring 202 is smaller than the diameter of the baffle plate 401. The top of the barrier ring 202 is concave, and the concave part is arc-shaped, which plays a role in guiding the nitrogen foam, so that when it impacts the top of the barrier ring 202, it will flow toward the center along the arc surface. The guide fins 203 are arc-shaped, and the nitrogen foam will form a vortex in the process of flowing from the top of the barrier ring 202 to the center, and rush towards the circular filter screen 204 at a certain angle and speed. This dynamic impact makes it easier for the bubbles to be divided into small bubbles by the circular filter screen 204, thereby improving the subsequent fracturing effect.

[0044] A sliding groove 405 is provided at the bottom of the snowflake block 402, and a sliding sleeve 406 is slidingly provided on the inner surface wall of the sliding groove 405. The bottom of the sliding sleeve 406 is fixedly connected to the center of the inner bottom of the fracturing head shell 201, and a strong spring 407 is fixedly connected between the inner bottom of the sliding sleeve 406 and the inner top of the sliding groove 405. The top of the baffle 401 and the bottom of the barrier ring 202 are in conflict, and the sliding sleeve 406 plays a role in guiding the snowflake block 402 so that it can only move in the vertical direction. During the fracturing process of pumping nitrogen foam, as the snowflake block 402 descends, the strong spring 407 will be compressed and contracted. When the fracturing operation is stopped, the rebound of the strong spring 407 will push the snowflake block 402 to move upward and reset. After the snowflake block 402 is reset, its top baffle 401 will fit with the barrier ring 202 on the inner wall of the fracturing head shell 201, thereby forming a closed state between the mixing shell 101 and the fracturing head shell 201. At the same time, the injection head 504 will also retract into the fracturing head shell 201 and the plug 508 and the inner shrinkage sleeve 506 will re-seal the interior of the injection head 504 to prevent backflow. During the backflow process, due to the high pressure after the nitrogen foam is injected into the formation, the plug 508 will be pressurized under the action of the pressure, so that the inner shrinkage sleeve 506 and the plug 508 slowly approach each other. At the end of the backflow, as the pressure decreases, the inner shrinkage sleeve 506 and the plug 508 will fit together, without affecting the backflow operation.

[0045] The bottom of the second slider 502 is provided with an injection channel 505, and the other end of the injection channel 505 is connected to the interior of the injection head 504. The outer surface of the injection head 504 is threaded and penetrates the outer surface of the fracturing head shell 201. A retracted sleeve 506 is fixedly connected to the position near the middle between the inner surface walls of the injection head 504. The outer surface of the first slider 501 close to the injection head 504 is rotatably connected to a connecting rod 507. The outer surface of the connecting rod 507 penetrates the outer surface of the second slider 502. The end of the connecting rod 507 away from the first slider 501 is fixedly connected to a plug 508. The inner diameter of the retracted sleeve 506 is smaller than the outer diameter of the plug 508, and the outer surfaces of the retracted sleeve 506 and the plug 508 fit together. The first guide groove 403 is vertically arranged, and the second guide groove 404 is inclined. When the snowflake block 402 moves downward, the inclined second guide groove 404 will The block 502 generates an oblique thrust, and the vertical first guide groove 403 does not generate an oblique thrust on the first slider 501. At the same time, the injection head 504 is limited by the guide sleeve 205 and does not move up and down. Therefore, the second slider 502, which is subjected to the oblique thrust, pushes the end of the injection head 504 horizontally to slide toward the outside of the fracturing head shell 201, thereby tightly pressing against the formation wall. During this process, the retracted sleeve 506 inside the injection head 504 will move accordingly, while the plug 508 rotatably connected to the first slider 501 through the connecting rod 507 is relatively stationary. Therefore, the retracted sleeve 506 and the plug 508 will separate, thereby forming a passage state inside the injection head 504. Subsequently, under the action of pressure, the nitrogen foam in the fracturing head shell 201 will enter the injection head 504 from the injection channel 505 below the second slider 502 and then be injected into the wellbore formation wall to complete the fracturing operation.

[0046] The present invention is used in the following steps: when in use, the device is sent to the specified depth of the oil well through the pipeline, and then the fracturing fluid is quantitatively pumped into the liquid inlet 103 through the pipeline, and nitrogen is pumped into the air inlet pipe 104. After the nitrogen and fracturing fluid pass through the air inlet 102 and the liquid inlet 103, they collide and complete the initial mixing. Then, under the action of pressure, the two enter the spiral mixing channel 106 and are transported to the bubble outlet 107. During the process, they rotate in the spiral mixing channel 106 and continuously collide, shear and knead with each other, thereby forming nitrogen foam and then start to be discharged in large quantities through the bubble outlet 107 with a larger diameter. When the mixing shell 101 and the fracturing head shell 201 are transported downward, the pressure in the space between the mixing shell 101 and the fracturing head shell 201 will gradually increase. When the pressure is greater than the resistance of the formation wall to the injection head 504, the baffle 401 will drive the snowflake block 402 to start moving downward. During the process, the strong spring 407 will be compressed. At this time, the nitrogen foam enters the fracturing head shell 201 through the gap between the barrier ring 202 and the baffle 401. When the snowflake block 402 moves downward, the inclined second guide groove 404 will generate an oblique thrust on the second slider 502, and the vertical first guide groove 403 will not generate an oblique thrust on the first slider 501. At the same time, the injection head 50 The guide sleeve 205 limits the position of the second slider 502, which is subject to the oblique thrust, and does not move up and down. Therefore, the second slider 502, which is subjected to the oblique thrust, pushes the end of the injection head 504 to slide toward the outside of the fracturing head housing 201, thereby tightly pressing against the formation wall to avoid a gap between the formation wall and the fracturing head during the injection of nitrogen foam. During this process, the retracted sleeve 506 inside the injection head 504 will move accordingly, while the plug 508, which is rotatably connected to the first slider 501 through the connecting rod 507, remains relatively stationary. Therefore, the retracted sleeve 506 and the plug 508 will separate, thereby forming a passage state inside the injection head 504. Subsequently, under the action of pressure, the injection head 504 is opened. In this way, the nitrogen foam in the fracturing head housing 201 will enter the injection head 504 from the injection channel 505 below the second slider 502 and then be injected into the wellbore formation wall to complete the fracturing operation. As the fracturing operation of the formation wall proceeds, the resistance to the injection head 504 will weaken accordingly. Therefore, the injection head 504 will gradually penetrate into the formation wall, and the baffle 401 will gradually move downward synchronously, which can effectively prevent the fracturing fluid from leaking into the gap between the fracturing head and the formation wall. This not only improves the fracturing effect, but also avoids the safety hazard of abnormal local formation pressure caused by nitrogen foam leaking into the gap between the fracturing head and the formation wall.

[0047] Example 2: Figure 2 、 Figure 4 and Figure 5-Figure 7As shown, the difference between the embodiment and the embodiment is that the top of the connecting column 301 is fixedly connected to the driving blade 302, the bottom of the connecting column 301 is fixedly connected to the connecting sleeve 304, and a circular seat 306 is provided between the inner surface walls of the connecting sleeve 304 near the bottom. The circular seat 306 is fixedly connected to the top center of the baffle 401. The flow energy generated when the discharged nitrogen foam in the mixing shell 101 enters the fracturing head shell 201 will act on the driving blade 302 and cause it to rotate. When the driving blade 302 rotates, it will drive the connecting sleeve 304 to rotate.

[0048] A wave groove 307 is provided on the outer surface of the circular seat 306, and four protrusions 305 are fixedly connected to the inner wall of the connecting sleeve 304. The four protrusions 305 are distributed in a ring on the outer side of the circular seat 306, and the opposite ends of the four protrusions 305 are slidably embedded in the lowest point of the inner wall of the wave groove 307. When the connecting sleeve 304 rotates, the protrusions 305 on the inner wall will slide in the wave groove 307 on the surface of the circular seat 306. There is a height difference in the path of the wave groove 307. Therefore, during the rotation of the connecting sleeve 304, the connecting column 301 and the driving blade 302 will continue to move up and down rapidly. The wave groove 307 is composed of four sections of V-shaped grooves connected end to end.

[0049] The present invention uses the following steps: the flow energy generated when the nitrogen foam discharged from the mixing shell 101 enters the fracturing head shell 201 will act on the driving blade 302 and cause it to rotate. When the driving blade 302 rotates, the connecting sleeve 304 will rotate outside the circular seat 306. During this process, the protrusion 305 on the inner wall of the connecting sleeve 304 will slide in the wave groove 307 on the surface of the circular seat 306. Since there is a height difference in the wave groove 307 path, during the rotation of the connecting sleeve 304, the connecting column 301 and the driving blade 302 will continue to move up and down rapidly. According to Newton's second law, in this process, the vertical There is acceleration in the direction, which will generate additional force acting on the spoiler 401, causing it to shake up and down at a high frequency in a small range. When the spoiler 401 moves up and down, the injection head 504 will shake laterally. At the same time, since the injection head 504 thread penetrates the guide sleeve 205 and the fracturing head shell 201, it will continue to rotate slightly forward and backward during the lateral shaking due to the action of the thread. Therefore, after the injection head 504 contacts the formation wall, it will be in a state of impact and rotation. Its conical end can effectively penetrate the formation wall for fracturing operations, thereby avoiding nitrogen foam leakage and further improving the fracturing effect.

[0050] Example 3: Figure 2 、 Figure 4 、 Figure 6 and Figure 7As shown, the difference between the embodiment and the embodiment is that a plurality of functional plates 303 are fixedly connected to the outer surface of the connecting column 301 at equal intervals. The functional plates 303 are higher than the barrier ring 202. The functional plates 303 are composed of a hard outer frame and an inner filter. When rotating with the connecting column 301, the functional plates 303 have the effect of mixing, stirring and shearing the nitrogen foam flowing through. When the functional plates 303 follow the connecting column 301 to be lowered to the lowest point, they will not come into contact with the barrier ring 202.

[0051] A circular filter screen 204 is fixedly connected between the inner surface walls of the barrier ring 202. The circular filter screen 204 is annular, and the inner surface wall of the circular filter screen 204 fits the outer surface of the connecting column 301. Six guide sleeves 205 are equidistantly fixedly connected to the inner surface wall of the fracturing head housing 201. The guide sleeve 205 and the injection head 504 are threadedly connected. The circular filter screen 204 is mainly used to further refine the nitrogen foam flowing through to form small bubbles. The small bubbles have higher surface energy and are not easy to break, so that the small bubbles can better carry the proppant in the fracturing fluid and improve the fracturing effect. The guide sleeve 205 plays a role in limiting the injection head 504, improving the stability of the injection head 504 during lateral movement. The two are threadedly connected, so when the injection head 504 moves inside the guide sleeve 205, a rotation effect will be generated.

[0052] The use steps of the present invention are as follows: when the driving blade 302 rotates, the connecting column 301 will drive the functional plate 303 on the surface to rotate rapidly, thereby further mixing the nitrogen foam passing through and preventing bubble aggregation. The middle of the functional plate 303 is in the shape of a filter screen, which will generate physical shear force on the nitrogen foam passing through while stirring, thereby forming smaller bubbles. At the same time, the circular filter screen 204 arranged on the inner side of the barrier ring 202 is arranged on the path that the nitrogen foam must pass through, which can further refine the bubbles. The small bubbles have higher surface energy, better bearing capacity, and are not easy to break, thereby improving the quality of the nitrogen foam and the fracturing effect.

[0053] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nitrogen foam generator for oil well fracturing, comprising a mixing assembly (1), characterized in that: A fracturing head assembly (2) is installed at the bottom of the mixing assembly (1), a pushing assembly (4) is arranged inside the fracturing head assembly (2), a shaking assembly (3) is arranged on the top of the pushing assembly (4), and an injection assembly (5) is arranged outside the pushing assembly (4); The mixing assembly (1) comprises a mixing shell (101); The fracturing head assembly (2) comprises a fracturing head housing (201); The shaking component (3) includes a connecting column (301); The pushing assembly (4) comprises a baffle (401), a snowflake block (402) is fixedly connected to the bottom of the baffle (401), six first guide grooves (403) are equidistantly formed on the top of the snowflake block (402) near the middle, and six second guide grooves (404) are equidistantly formed on the outer surface of the snowflake block (402), and the first guide grooves (403) and the second guide grooves (404) are connected; The number of the injection assemblies (5) is set to six, each comprising a first slider (501) and a second slider (502), wherein the first slider (501) is slidably embedded in the interior of the first guide groove (403), and the second slider (502) is slidably embedded in the interior of the second guide groove (404), and a bearing (503) is installed on the outer surface of the second slider (502), and a spray head (504) extending outward is installed on the outer surface of the bearing (503); An injection channel (505) is provided at the bottom of the second slider (502), and the other end of the injection channel (505) is connected to the interior of the injection head (504); the outer surface of the injection head (504) is threadedly penetrated through the outer surface of the fracturing head shell (201); an inner shrink sleeve (506) is fixedly connected near the middle position between the inner surface walls of the injection head (504); the outer surface of the first slider (501) close to the injection head (504) is rotatably connected to a connecting rod (507); the outer surface of the connecting rod (507) penetrates the outer surface of the second slider (502); the end of the connecting rod (507) away from the first slider (501) is fixedly connected to a plug (508); the inner diameter of the inner shrink sleeve (506) is smaller than the outer diameter of the plug (508), and the outer surfaces of the inner shrink sleeve (506) and the plug (508) are in contact with each other; the first guide groove (403) is vertically arranged, and the second guide groove (404) is inclined.

2. The nitrogen foam generator for oil well fracturing according to claim 1, characterized in that: An air inlet (102) and a liquid inlet (103) are provided at the top of the mixing shell (101); a spiral mixing channel (106) is provided inside the mixing shell (101); an upwardly concave bubble discharge port (107) is provided at the bottom of the mixing shell (101); the air inlet (102) and the liquid inlet (103) are both communicated with the upper opening of the spiral mixing channel (106); the lower opening of the spiral mixing channel (106) is communicated with the bubble discharge port (107); an air inlet pipe (104) is threadedly connected between the inner surface walls of the air inlet (102); a liquid inlet pipe (105) is threadedly connected between the inner surface walls of the liquid inlet (103); and a joint (108) is fixedly connected to the bottom end of the mixing shell (101).

3. The nitrogen foam generator for oil well fracturing according to claim 2, characterized in that: The outer surface of the joint (108) is threadedly connected to the inner surface wall of the fracturing head shell (201), and the bottom of the mixing shell (101) is in conflict with the top of the fracturing head shell (201).

4. The nitrogen foam generator for oil well fracturing according to claim 1, characterized in that: A barrier ring (202) is fixedly connected to a position near the middle between the inner surface walls of the fracturing head housing (201); the top of the barrier ring (202) is concave; a plurality of guide fins (203) are equidistantly arranged on the top of the barrier ring (202); and the inner aperture of the barrier ring (202) is smaller than the diameter of the baffle (401).

5. The nitrogen foam generator for oil well fracturing according to claim 1, characterized in that: A sliding groove (405) is provided at the bottom of the snowflake block (402), a sliding sleeve (406) is slidably provided on the inner surface wall of the sliding groove (405), the bottom of the sliding sleeve (406) is fixedly connected to the center of the inner bottom of the fracturing head shell (201), a strong spring (407) is fixedly connected between the inner bottom of the sliding sleeve (406) and the inner top of the sliding groove (405), and the top of the baffle (401) is in conflict with the bottom of the barrier ring (202).

6. The nitrogen foam generator for oil well fracturing according to claim 1, characterized in that: The top of the connecting column (301) is fixedly connected to a driving blade (302), the bottom of the connecting column (301) is fixedly connected to a connecting sleeve (304), a circular seat (306) is provided between the inner surface walls of the connecting sleeve (304) near the bottom, and the circular seat (306) is fixedly connected to the top center of the spoiler (401).

7. The nitrogen foam generator for oil well fracturing according to claim 6, characterized in that: The outer surface of the circular seat (306) is provided with a wave groove (307), and the inner surface wall of the connecting sleeve (304) is fixedly connected with four protrusions (305). The four protrusions (305) are distributed in an annular manner on the outer side of the circular seat (306), and the opposite ends of the four protrusions (305) are slidably embedded in the lowest part of the inner surface wall of the wave groove (307).

8. The nitrogen foam generator for oil well fracturing according to claim 1, characterized in that: A plurality of functional plates (303) are fixedly connected to the outer surface of the connecting column (301) at equal intervals, and the functional plates (303) are higher than the barrier ring (202).

9. The nitrogen foam generator for oil well fracturing according to claim 4, characterized in that: A circular filter (204) is fixedly connected between the inner surface walls of the barrier ring (202), the circular filter (204) is annular, and the inner surface wall of the circular filter (204) is in contact with the outer surface of the connecting column (301). Six guide sleeves (205) are fixedly connected at equal intervals to the inner surface wall of the fracturing head housing (201), and the guide sleeves (205) and the injection head (504) are rotatably connected in a threaded manner.

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