An ultra-high pressure stratum plugging and grouting device for drilling operation and a method thereof

Abstract

The present application relates to the technical field of drilling in soil rock, and particularly relates to an ultra-high pressure stratum plugging and grouting device for drilling operation and a method thereof, which comprises a tool pipe body, an axial movable core and an elastic assembly, realizes flow channel switching logic by using grouting back pressure, sprays slurry mixed with an excitation agent from a central nozzle for filling and anti-scouring reinforcement of a large leakage stratum under low pressure working condition, reverses the axial movable core by back pressure under high pressure working condition, physically closes the catalytic flow channel and leads the pure slurry to be sprayed from the side wall flow guide hole, generates an ultra-high pressure jet by using a small cross-sectional area to penetrate the micro-cracks of the well wall, and is provided with a trigger sensor at the end of the device to feed back the downhole compaction signal. The present application solves the technical pain points of well leakage, well wall collapse and dynamic water dilution in the drilling process, realizes intelligent mechanical regulation and control of the downhole grouting process, and has the advantages of strong penetration, phase self-adaptation and construction precision.

Description

Technical Field

[0001] This invention relates to the field of drilling technology for soil and rock formations, and more particularly to an ultra-high pressure formation sealing and grouting device and method for drilling operations. Background Technology

[0002] In the fields of energy drilling and extraction, geothermal development, and deep hole drilling, the stability of the borehole formation is crucial to ensuring operational safety. During the process of forming a wellbore through rotary drilling, fractured formations, caverns, or highly permeable fractures are frequently encountered. Failure to promptly plug and reinforce these formations can lead to serious drilling fluid losses (lost circulation), wellbore collapse, or blowouts. Ultra-high pressure grouting, as a highly efficient method for wellbore reinforcement and plugging, is widely used in the pretreatment and repair of borehole formations.

[0003] However, existing downhole grouting technologies have several significant shortcomings in addressing formation losses. First, they rely on a single mode and cannot dynamically respond to formation losses. For large caverns or severely lost circulation zones, activators (accelerators) are needed to prevent grout loss and downhole fluid erosion. However, for micro-fractures in the formation, the grout requires a long initial setting time and extremely high pressure to penetrate, making it difficult for existing equipment to adaptively switch between the two modes within the same well section. Second, when injecting grout mixed with activators, traditional equipment is prone to instantaneous solidification at micro-fractures in the wellbore, leading to blockages. Furthermore, the fixed cross-sectional area nozzle cannot generate localized high-pressure jets when resistance increases, limiting the penetration radius to the lost circulation zone. Additionally, blind injection is prevalent, lacking real-time feedback. Operators cannot accurately determine whether each section of the deep well has been filled or reached a compacted state, often relying on experience, which can easily result in uneven wellbore reinforcement or excessive grout waste. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides an ultra-high voltage formation sealing grouting device and method for drilling operations.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A grouting device for sealing and plugging ultra-high voltage formations in drilling operations includes a tool tube body. A grouting pre-hole is provided at the front end of the tool tube body. A grouting conduit is coaxially arranged inside the tool tube body. A catalytic conduit and an axially movable core are also provided inside the tool tube body. An activator delivery pipe is connected to the outside of the catalytic conduit. A mixing chamber is provided inside the axially movable core. One end of the mixing chamber is connected to both the grouting conduit and the catalytic conduit. The other end of the mixing chamber is provided with a sidewall guide hole and a central nozzle located on the axis of the axially movable core. An elastic component is sleeved on the axially movable core. The elastic component is used to abut the axially movable core against the front end of the tool tube body, allowing the central nozzle to extend to the outside through the grouting pre-hole. The front end of the tool tube is also provided with a grouting side hole. The grouting side hole is misaligned with the side wall guide hole when the elastic component is not compressed. The elastic component is compressed when the axial movable core moves into the inner cavity of the tool tube due to the back pressure of the slurry outside the well. When the elastic component is compressed to the extreme value, the grouting side hole is connected to the side wall guide hole. A normally open on / off valve is provided in the catalyst guide tube. A linkage rod is fixed at the end of the axial movable core away from the central nozzle. The linkage rod moves axially synchronously with the axial movable core. When the axial movable core is pushed back into the inner cavity of the tool tube to the limit value, it triggers the on / off valve to switch from the open state to the closed state.

[0006] Furthermore, at least two sets of sidewall guide holes are provided, and the two sets of sidewall guide holes are arranged along the axial direction of the axial movable core. The number of grouting side holes corresponds to the number of sidewall guide holes, and the spacing is the same. When the axial movable core retracts to the predetermined position, that is, the extreme value of the elastic component compression, the grout can act on the well wall simultaneously in the form of multiple horizontal circumferential jets, thereby increasing the effective reinforcement radius of a single grouting section.

[0007] Furthermore, the flow area of ​​the sidewall guide holes is smaller than that of the central nozzle. The central nozzle is used to output a mixture of slurry and activator during the large defect filling stage, while the sidewall guide holes utilize local jet pressure to output high-pressure slurry during the micro-fracture infiltration stage. By changing the cross-sectional area of ​​the fluid flow, the pressure and velocity are increased. The large flow area of ​​the central nozzle meets the requirements of high flow rate and high speed during the large defect filling stage, rapidly filling cavities or fractures. The sidewall guide holes, with their smaller flow area than the central nozzle, allow the same pumping flow rate to be squeezed into a smaller physical space when the grouting mode is switched to sidewall guidance, increasing the velocity and converting static pressure energy into a kinetic jet. This localized high-pressure jet possesses fracturing capabilities, overcoming the strong capillary resistance and interfacial friction within micro-fractures, forcibly pushing the slurry deep into dense formations.

[0008] Furthermore, the opening and closing valve includes a valve seat and a movable sealing element that cooperates with the valve seat. The end of the linkage rod is axially opposite to the movable sealing element. When the axially movable core pushes back into the inner cavity of the tool tube, the linkage rod pushes against the movable sealing element and moves to a sealing fit with the valve seat, thereby cutting off the supply of activator in the catalyst conduit. When the axially movable core is displaced due to back pressure, the linkage rod, through its pushing action, forces the movable sealing element to seal against the valve seat. Cutting off the supply of activator allows the slurry to require a longer setting time in the lateral micro-jet mode to complete long-distance transport in the micro-fractures, avoiding premature solidification of the slurry at the sidewall guide hole, which could lead to tool jamming, and also preventing premature solidification at the opening of the micro-fractures in the well wall, which could block the entry of subsequent slurry.

[0009] Furthermore, the tool tube body is also provided with a limiting cavity communicating with the pre-grouting hole. A limiting ring is provided on the outer wall of the axially movable core. The elastic component is located on the side of the limiting ring away from the central nozzle. One end of the elastic component abuts against the limiting ring, and the other end abuts against the end wall of the limiting cavity. The limiting ring allows the axially movable core to move axially within the limited space of the limiting cavity; that is, without external force, the axially movable core abuts against the front end of the tool tube body. After the well wall is filled with grout, the grout pushes back the axially movable core, compressing the elastic component, thereby opening the sidewall guide hole, increasing the grout impact pressure, and simultaneously cutting off the supply of the activator.

[0010] Furthermore, the grouting conduit and the catalytic conduit are respectively connected to one end of the mixing chamber via folded tubes. Since both the grouting conduit and the catalytic conduit are fixedly installed inside the tool tube, and the axially movable core undergoes axial displacement relative to the tool tube, the connection via folded tubes ensures the continuous conduction and supply of grout in the grouting conduit and activator in the catalytic conduit.

[0011] Furthermore, the mixing chamber is located at the end of the axially movable core facing the central nozzle, and a guide pipe is also provided inside the axially movable core. The mixing chamber is connected to each folded pipe through the guide pipe. The mixing chamber is located at the end closest to the central nozzle, which shortens the residence time of the mixed slurry in the mixing chamber and reduces the risk of the quick-setting slurry solidifying and clogging the pipeline.

[0012] Furthermore, the front end of the axially movable core is provided with a guide plate to increase the contact area. The guide plate is adapted to the inclined surface of the front end of the tool tube body, and a mud-blocking strip is provided at the free end of the guide plate. The free end of the mud-blocking strip abuts against the outer wall of the tool tube body. The inclined surface design of the guide plate is adapted to the front end of the tube body, which increases the contact area with the external formation, making the back pressure feedback more stable and avoiding sudden jumps in the axially movable core movement caused by excessive local stress. The slightly elastic curved mud-blocking strip maintains contact with the outer wall of the tool tube body throughout the extension and retraction of the axially movable core, preventing fine sand and rock cuttings from entering the guide plate and tool tube body during the drilling process and clogging the guide plate and axially movable core, thus preventing them from moving back.

[0013] Furthermore, the elastic coefficient of the elastic component is matched with the critical compaction back pressure of the soil and rock defects, which is used to set the logical threshold for the device to switch from high-flow-rate filling to high-pressure fracturing. In well formation plugging, different rock formations have different capacities for accepting slurry, and the rates at which back pressure is generated also differ. By calibrating the elastic coefficient to match the critical compaction back pressure of the formation defects in that well section, the device ensures that it maintains high-flow-rate filling before the cavity is completely filled, and automatically switches to high-pressure fracturing mode the instant it is filled.

[0014] Furthermore, an alloy scraper is provided on the side of the front end of the tool tube, and a drive drill rig is connected to the rear end of the tool tube to drive its rotation, used for real-time cleaning of loose debris from the borehole wall during downhole grouting. The alloy scraper is made of high-hardness tungsten carbide material, and its spiral distribution angle is optimized, enabling it to mechanically cut and clean loose mud cake and collapsed debris on the well wall while the drive drill rig rotates the tool tube. Secondly, the centrifugal force field generated by the rotation can assist the grout in penetrating into radial fractures. While cleaning loose debris, the alloy scraper reduces the sway amplitude of the grouting tube under high-speed rotation, protecting the internal linkage mechanism.

[0015] Furthermore, a trigger sensor is installed on the inner wall of the tool tube. When the axially movable core is pushed back to its limit value, it contacts the trigger sensor and sends a grouting compaction signal for that section to the ground control terminal. Since the pushback of the axially movable core is driven by the back pressure generated by the grouting compaction, when it contacts the sensor, it indicates that the formation defects in that grouting section have reached the physical limit of saturation grouting. The sensor converts this physical contact into an electronic signal and transmits it to the ground, providing operators with a basis for tube withdrawal and solving the problem of false pressure interference that previously existed when determining the end of grouting solely based on pump pressure gauge readings.

[0016] A grouting method for an ultra-high voltage formation plugging grouting device used in drilling operations includes the following steps: S1: In drilling operations, after a borehole is formed by rotary drilling, the tool casing is sent to the bottom of the well. S2: Start grouting. Under low back pressure, the axial moving core is in the front position, and a mixed grout containing an activator is injected from the central nozzle for anti-dilution filling, coagulation, and reinforcement of lost formations or void defects. S3: As the defects are filled and the back pressure increases, the axial moving core moves backward, automatically closes the catalyst conduit and opens the sidewall guide hole to spray slurry without activator. High pressure slurry is output in the micro-fracture of the well wall using a small cross-sectional area, while avoiding activator blockage of the sidewall guide hole. S4: After receiving the signal, the ground control terminal slowly retracts the tool tube and uses the grouting pressure difference to reinforce and repair the borehole wall in sections. Repeat steps S2-S3 until the entire hole and the gaps around the hole are filled.

[0017] Furthermore, in step S3 above, after the axial moving core retracts and switches to the mode, the slurry maintains a long initial setting time in the microcracks due to the cessation of activator introduction, and the dynamic pressure difference generated by the rotation of the device further increases the penetration radius of the slurry.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention solves the contradiction between filling large lost circulation zones in boreholes and reinforcing micro-fractures in well walls by setting an axial movable core and elastic components and using bottom hole back pressure as a command to automatically switch between two modes: front-end high-flow-rate filling and lateral ultra-high-pressure permeation.

[0019] 2. When entering the microfracture reinforcement stage, the device can automatically and physically cut off the activator flow channel to prevent the slurry from solidifying too early inside the tool. At the same time, it uses the sidewall guide holes with smaller cross-sectional area to output the slurry, which significantly improves the penetration depth of the slurry into the formation around the well wall. 3. This invention achieves real-time feedback on the grouting quality of the entire borehole section through the physical linkage between the built-in trigger sensor and the axial moving core. Operators can make precise step-by-step retraction based on the signal, which greatly improves well completion efficiency and saves material costs. 4. The adjustment process of this invention is driven entirely by the coupling of fluid kinetic energy and mechanical structure, without relying on electronic sensors for flow channel control, and can operate stably under deep well conditions with high pressure and high mud content; 5. This invention automatically switches between two modes: high-flow-rate filling at the front end and ultra-high-pressure lateral permeation, resolving the contradiction between filling large lost circulation zones in boreholes and reinforcing micro-fractures in the well wall. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural diagram of the present invention in its conventional state; Figure 2 This is a schematic cross-sectional view of the present invention under the compressed state of the elastic component; Figure 3 This is a schematic diagram of the planar structure of the tool tube; Figure 4 This is a schematic diagram of the planar structure of the axially movable core; Attached diagram labels: 1-Tool tube body, 101-Grouting front hole, 102-Grouting side hole, 103-Limiting cavity, 2-Grouting guide tube, 3-Catalyst guide tube, 4-Axial moving core, 401-Mixing cavity, 5-Side wall guide hole, 6-Central nozzle, 7-Elastic component, 8-Opening and closing valve, 9-Linkage rod, 10-Limiting ring, 11-Folded tube, 12-Guide tube, 13-Guide plate, 14-Mudguard strip, 15-Alloy scraper, 16-Trigger sensor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0022] Example 1, as Figures 1-4As shown, the present invention discloses an ultra-high pressure formation plugging grouting device for drilling operations, comprising a tool tube body 1, a grouting front hole 101 at the front end of the tool tube body 1, a grouting conduit 2 coaxially disposed inside the tool tube body 1, a catalytic conduit 3 and an axially movable core 4 disposed inside the tool tube body 1, an activator delivery pipe connected to the outside of the catalytic conduit 3, a mixing chamber 401 disposed inside the axially movable core 4, one end of the mixing chamber 401 being connected to the grouting conduit 2 and the catalytic conduit 3 respectively, and the other end of the mixing chamber 401 being provided with a side wall guide hole 5 and a central nozzle 6 located on the axis of the axially movable core 4, and an elastic component 7 being sleeved on the axially movable core 4, the elastic component 7 being used to abut the axially movable core 4 against the front end of the tool tube body 1, so that the central nozzle 6 extends to the outside through the grouting front hole 101; The front end of the tool tube 1 is also provided with a grouting side hole 102. The grouting side hole 102 is misaligned with the side wall guide hole 5 when the elastic component 7 is not compressed. The elastic component 7 is compressed when the axial movable core 4 moves into the inner cavity of the tool tube 1 by the back thrust of the slurry outside the well. When the elastic component 7 is compressed to the extreme value, the grouting side hole 102 is connected to the side wall guide hole 5. The catalyst guide tube 3 is provided with a normally open on / off valve 8. The end of the axial movable core 4 away from the central nozzle 6 is fixedly provided with a linkage rod 9. The linkage rod 9 moves axially synchronously with the axial movable core 4. When the axial movable core 4 is pushed back into the inner cavity of the tool tube 1 by pressure to the extreme value, it triggers the on / off valve 8 to switch from the open state to the closed state.

[0023] Specifically, under initial operating conditions, due to the large formation leakage cavities, the grout experiences little resistance, and the elastic component 7 is in a naturally extended state. At this time, the sidewall guide hole 5 and the grouting side hole 102 are in a misaligned and blocked state, and all grouting energy is concentrated at the central nozzle 6. As the leakage layer gradually fills, the downhole back pressure rises and exceeds the preset threshold. The pressure acts in the opposite direction through the central nozzle 6 on the front end of the axially movable core 4, forcing it to overcome the elastic force and retreat into the inner cavity of the tool tube 1. After the axially movable core 4 moves back, the sidewall guide hole 5 and the grouting side hole 102 coincide and become connected, switching the grouting mode from front-end filling to radial permeation. In addition, the drive linkage rod 9 touches the on / off valve 8, cutting off the activator in the path to ensure that when entering the micro-fracture reinforcement stage, the output is high-pressure pure grout without activator, avoiding the blockage of micro-fractures in the well by the fast-setting grout.

[0024] Preferably, to ensure that the linkage rod 9 does not jam in harsh environments with high mud content, its mating surface is provided with spiral or longitudinal mud-scraping and sand-removing grooves. Furthermore, when the axial movable core 4 undergoes a push-back displacement, the high-speed flowing pure slurry inside will generate a hydraulic scouring effect on the operating area of ​​the on / off valve 8, preventing the deposition and seizing of high-viscosity mud in the mechanical linkage parts. In addition, to adapt to the high-pressure environment of deep wells, an internal and external hydrostatic pressure balancing structure is provided between the axial movable core 4 and the tool tube 1 (such as setting a balancing piston in the spring cavity, or making the spring cavity connected to the external annulus). This ensures that the elastic component 7 is not affected by absolute hydrostatic pressure in deep wells, and only responds to the dynamic pressure difference generated by grouting (i.e., formation compaction back pressure). Even in deep wells above 50 MPa, the elastic component 7 can still respond according to the preset elastic coefficient k value, avoiding high-pressure jamming.

[0025] At least two sets of sidewall guide holes 5 are provided, and the two sets of sidewall guide holes 5 are arranged along the axial direction of the axial movable core 4. Each set has two radially symmetrical sidewall guide holes 5. The number of grouting side holes 102 corresponds to the number of sidewall guide holes 5, and the spacing is the same. Specifically, when the axial movable core 4 retracts to the predetermined position, that is, the extreme value of the compression of the elastic component 7, the grout can act on the well wall simultaneously in the form of multiple horizontal circumferential jets, significantly improving the effective reinforcement radius of a single grouting section. In actual drilling plugging, the main grout can penetrate into the fractured formation around the well wall in a spiral or annular path. Through the stress superposition effect of multiple pores, drilling fluid residue and formation water in the fractures are forcibly removed, and the formed reinforced shell has strong circumferential compressive strength. Even if local rock formations collapse and become blocked, other pores can still continuously output grout, ensuring the continuity of downhole plugging operations and reinforcement quality.

[0026] The flow area of ​​the sidewall guide hole 5 is smaller than that of the central nozzle 6. The central nozzle 6 is used to output a mixture of grout and activator during the large defect filling stage, while the sidewall guide hole 5 utilizes local jet pressure to output high-pressure grout during the micro-fracture permeation stage. Specifically, by changing the cross-sectional area of ​​the fluid flow, the pressure and flow velocity are increased. The large flow area design of the central nozzle 6 meets the requirements of high flow rate and high speed during the large defect filling stage, rapidly filling cavities or fractures. The flow area of ​​the sidewall guide hole 5 is smaller than that of the central nozzle 6. When the grouting mode is switched to sidewall permeation, the same pumping flow rate is squeezed into a smaller physical space, increasing the flow velocity and converting static pressure energy into kinetic energy jet. The local high-pressure jet has a fracturing capability, overcoming the strong capillary resistance and interfacial friction within micro-fractures, forcibly pushing the grout deep into the dense formation. Furthermore, the opening of the sidewall guide hole 5 allows the overflow portion of the grout injected at the end of the tool tube 1 to overflow from both sides.

[0027] The on / off valve 8 includes a valve seat and a movable plugging component that cooperates with the valve seat. The end of the linkage rod 9 is axially opposite to the movable plugging component. When the axially movable core 4 pushes back into the inner cavity of the tool tube 1, the linkage rod 9 pushes against the movable plugging component and moves to a sealing fit with the valve seat, thereby cutting off the supply of activator in the catalyst conduit 3. Specifically, when the axially movable core 4 is displaced due to back pressure, the linkage rod 9, through its pushing action, forces the movable plugging component to form a tight seal with the valve seat. Cutting off the supply of activator allows the slurry to require a longer setting time in the lateral micro-jet mode to complete long-distance transport in the micro-fractures, avoiding premature solidification of the slurry at the sidewall guide hole 5 that could cause tool jamming, and also preventing premature solidification at the opening of the micro-fractures in the well wall, which could block the entry of subsequent slurry.

[0028] The tool tube body 1 is also provided with a limiting cavity 103 communicating with the grouting pre-hole 101. A limiting ring 10 is provided on the outer wall of the axially movable core 4. The elastic component 7 is located on the side of the limiting ring 10 away from the central nozzle 6. One end of the elastic component 7 abuts against the limiting ring 10, and the other end abuts against the end wall of the limiting cavity 103. Specifically, the limiting ring 10 allows the axially movable core 4 to move axially within the limited space of the limiting cavity 103, that is, without external force, the axially movable core 4 abuts against the front end of the tool tube body 1. After the well wall is filled with grout, the grout pushes back the axially movable core 4, compressing the elastic component 7, thereby opening the sidewall guide hole 5, increasing the grout impact pressure, and simultaneously cutting off the supply of the activator.

[0029] The grouting conduit 2 and the catalytic conduit 3 are respectively connected to one end of the mixing chamber 401 via the folded tube 11. Specifically, since the grouting conduit 2 and the catalytic conduit 3 are both fixedly installed inside the tool tube body 1, and the axially movable core 4 is axially displaced relative to the tool tube body 1, the connection via the folded tube 11 ensures the continuous conduction and supply of grout in the grouting conduit 2 and activator in the catalytic conduit 3.

[0030] The mixing chamber 401 is located at the end of the axially movable core 4 facing the central nozzle 6. A guide pipe 12 is also provided inside the axially movable core 4. The mixing chamber 401 is connected to each of the folded pipes 11 via the guide pipe 12. Specifically, the mixing chamber 401 is located at the end closest to the central nozzle 6, shortening the residence time of the mixed slurry within the mixing chamber 401 and reducing the risk of the quick-setting slurry solidifying and clogging the pipeline. Preferably, the inner wall of the guide pipe 12 is treated with hydrodynamic polishing, which effectively prevents cement particles from adhering to the wall and settling, ensuring that the slurry and activator achieve uniform mixing at the molecular level before spraying.

[0031] The tool tube 1 has an alloy scraper 15 on its front side. The rear end of the tool tube 1 is connected to a drive drill rig for rotating the tool tube 1, used to clean loose material from the borehole wall in real time during downhole grouting. Specifically, the alloy scraper 15 is made of high-hardness tungsten carbide, and its spiral distribution angle is optimized. This allows it to mechanically cut and clean loose mud cake and collapsed debris from the borehole wall as the tool tube 1 rotates with the drive drill rig. Furthermore, the centrifugal force generated by the rotation assists the grout in penetrating radial fractures. While cleaning loose material, the alloy scraper 15 reduces the sway amplitude of the grouting tube under high-speed rotation, protecting the internal linkage mechanism.

[0032] Example 2, based on Example 1, proposes an elastic component and trigger sensor for an ultra-high voltage formation plugging grouting device for drilling operations.

[0033] The elastic coefficient of the elastic component 7 is matched with the critical compaction back pressure of the rock and soil defects, and is used to set the logical threshold for the device to switch from high-flow filling to high-pressure fracturing. Specifically, in well formation plugging, different rock formations (such as loose sandstone and dense carbonate rock) have different capacities for accepting slurry, and the rate of back pressure generation is also different. By calibrating the elastic coefficient to match it with the critical compaction back pressure of the formation defects in that well section, the device ensures that it maintains high-flow filling before the cavity is completely filled, and automatically switches to high-pressure fracturing mode the moment it is filled. For example, in shallow drilling operations at a depth of 50-60 meters, the critical compaction back pressure of the formation is set to 1.8MPa to 2.5MPa according to the physical and mechanical parameters of the drilling formation (at this time, the slurry has basically filled the shallow large fractures or the voids generated by artificial drilling disturbance, and has begun to build up the squeezing pressure on the fracture wall). If the effective pressure-bearing area of ​​the axial movable core 4 in sensing back pressure is set to 40 cm², the comprehensive force parameters of the elastic component 7 are configured as follows to achieve precise mode switching. The preload is set to approximately 3,200 N to ensure that during the initial high-flow filling stage when the back pressure is below 0.8 MPa, the elastic component 7 can generate sufficient restoring force to keep the axial movable core 4 in the forward position, ensuring efficient mixing and ejection of the grout and activator at the front center nozzle 6. The elastic coefficient k is set to 140–180 N / mm. The effective mechanical stroke of the axial movable core 4 from the low-pressure filling position to the lateral high-pressure fracturing position is set to 50 mm. As grouting continues, when the grout within the formation defect at a depth of 50–60 meters reaches a compacted state and the back pressure rises to 2.5 MPa, the thrust acting on the movable core reaches 10,000 N. At this point, the thrust completely overcomes the preload and further compresses the elastic component 7, causing the axial movable core 4 to move precisely to its ultimate rear position. At this moment, the device precisely cuts off the catalytic conduit 3 via the linkage rod 9, and completely aligns the sidewall guide hole 5 with the grouting side hole 102. Due to the reduction in the cross-sectional area of ​​the side hole, the grouting pressure is instantly forced to increase from 2.5 MPa to 5.0 MPa or even higher.

[0034] A trigger sensor 16 is installed on the inner wall of the tool tube 1. When the axially movable core 4 is pushed back to its limit value, it contacts the trigger sensor 16 and sends a grouting compaction signal for that section to the ground control terminal. Specifically, since the pushback of the axially movable core 4 is driven by the back pressure generated by the grouting compaction, when it contacts the trigger sensor 16, it indicates that the formation defects in that grouting section have reached the physical limit of saturation grouting. The trigger sensor 16 converts this physical contact into an electronic signal and transmits it to the ground, providing operators with a basis for tube withdrawal and solving the problem of false pressure interference (such as false pressure caused by pipeline blockage) that previously existed when judging the end of grouting solely based on pump pressure gauge readings.

[0035] Example 3: Based on Example 1, this example proposes a guide plate for an ultra-high voltage formation sealing grouting device used in drilling operations.

[0036] The front end of the axial movable core 4 is provided with a guide plate 13 to increase the contact surface. The guide plate 13 is adapted to the inclined surface of the front end of the tool tube 1. A mud-blocking strip 14 is provided at the free end of the guide plate 13, and the free end of the mud-blocking strip 14 abuts against the outer wall of the tool tube 1. Specifically, the inclined surface design of the guide plate 13 is adapted to the front end of the tube, which increases the contact area with the external formation, making the back pressure feedback more stable and avoiding sudden jumps in the axial movable core 4 caused by excessive local stress. The mud-blocking strip 14 is an elastic curved strip that always maintains contact with the outer wall of the tool tube 1 during the extension and retraction of the axial movable core 4, preventing fine sand and rock cuttings from entering the guide plate 13 and the tool tube 1 during the drilling process and blocking or restricting the return movement of the guide plate 13 and the axial movable core 4.

[0037] Example 4, based on Example 2, proposes a grouting method for an ultra-high voltage formation plugging grouting device used in drilling operations, including the following steps: S1: After completing the drilling operation of the target well section by rotating the drilling tool, the drilling tool is withdrawn using the drilling rig's lifting system. Then, the tool tube 1 is connected to the end of the drill pipe and lowered to the preset plugging position at the bottom of the well through the inner cavity of the drill pipe, so that the guide plate 13 initially abuts against the bottom of the hole, and the nozzle residue is cleaned by circulating fluid pumped from the surface.

[0038] S2: The high-pressure dual-path pump on the ground is started. The slurry and activator are delivered through the grouting conduit 2 and the catalytic conduit 3, respectively. In areas with severe formation loss, cracks spreading outwards are formed around the borehole wall. There is no slurry back-push outside the guide plate 13, the elastic component 7 is not compressed, and the axially movable core 4 remains in contact with the front of the tool tube 1. The slurry is instantly activated in the mixing chamber 401 and then ejected at a high flow rate through the central nozzle 6. At this time, the mixed slurry has an extremely high initial setting rate and can quickly solidify in a dynamic water environment to form a hard support skeleton, seal large sinkholes, prevent slurry loss, and build a barrier against leakage.

[0039] S3: As filling proceeds, the formation space is compacted. When a large amount of grout is filled in this section, the continuously introduced grout will push the axial moving core 4 back and compress the elastic component 7. During this process, the linkage rod 9 strikes the opening and closing valve 8 to cut off the activator. When the compressed elastic component 7 is compressed to the extreme value state, the side wall guide hole 5 connects to the grouting side hole 102 (the compression process occurs instantaneously under the action of back pressure).

[0040] S4: The axial moving core 4 triggers sensor 16, and the ground personnel receive a signal that this section is filled. Subsequently, the drill pipe is slowly and uniformly raised. At this time, the slurry without activator is ejected at ultra-high pressure through the sidewall guide hole 5 with a smaller cross-sectional area (since the central nozzle 6 is almost full, the excess slurry is flushed out from the sidewall guide hole 5). Due to the absence of activator, the slurry remains fluid within the micro-fractures. Utilizing the dynamic pressure difference and physical splitting force generated by the rotation of the tool tube 1, the slurry is squeezed into the deep rock formation, forming a deep consolidation network. During the lifting process, circumferential jetting is performed, and the elastic component 7 gradually resets as the resistance decreases, and the device automatically returns to state S2. The operator controls the withdrawal speed of the tool tube 1, so that the device undergoes a composite reinforcement process of first filling large holes and then splitting micro-fractures in each section. This process is repeated until the entire lost well section has completed full-section, full-radial high-strength consolidation. Finally, the borehole is swept and re-drilled to complete the formation sealing.

[0041] In step S3 above, after the axially movable core 4 retracts and switches modes, the slurry maintains a long initial setting time in the microcracks due to the cessation of activator introduction, and the dynamic pressure difference generated by the rotation of the device further increases the penetration radius of the slurry.

[0042] In step S4 above, in addition to sending electronic signals, the trigger sensor 16, when the axially movable core 4 retracts to its extreme value, causes a momentary reduction in the total flow area, thereby generating a significant surface pump pressure hammer peak (mud pulse positive pressure difference) in the grouting pipeline. Surface operators can monitor this physical pressure change signal as an auxiliary verification, effectively filtering out interference from deep well mud fluid noise and achieving dual confirmation.

[0043] In step S4 above, the operator lifts the tool tube 1 in a step-by-step manner (or lifts it in sections according to the length of a single drill pipe column). Since the device can automatically switch between filling and high-pressure jet modes based on the real-time feedback of the formation back pressure at each section, it reduces the dependence on the accuracy of the ground lifting speed and effectively eliminates the operational errors caused by the elastic tension of the deep well drill pipe.

[0044] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A grouting device for sealing and grouting in ultra-high pressure formations for drilling operations, comprising a tool tube body (1), wherein a grouting pre-hole (101) is provided at the front end of the tool tube body (1), and a grouting conduit (2) is coaxially provided inside the tool tube body (1), characterized in that: The tool tube (1) is also provided with a catalytic conduit (3) and an axial movable core (4). The axial movable core (4) is provided with a mixing chamber (401). One end of the mixing chamber (401) is connected to the grouting conduit (2) and the catalytic conduit (3) respectively. The other end of the mixing chamber (401) is provided with a side wall guide hole (5) and a central nozzle (6) located on the axis of the axial movable core (4). The axial movable core (4) is covered with an elastic component (7). The elastic component (7) is used to abut the axial movable core (4) against the front end of the tool tube (1), so that the central nozzle (6) extends to the outside through the grouting front hole (101). The tool tube (1) is also provided with a grouting side hole (102) at the front end. The grouting side hole (102) is misaligned with the side wall guide hole (5) when the elastic component (7) is not compressed. The elastic component (7) is compressed when the axial moving core (4) of the slurry pushes back into the inner cavity of the tool tube (1). When the elastic component (7) is compressed to the extreme value, the grouting side hole (102) is connected to the side wall guide hole (5). The catalyst guide tube (3) is provided with a normally open opening and closing valve (8). The end of the axial moving core (4) away from the central nozzle (6) is fixed with a linkage rod (9). The linkage rod (9) moves axially synchronously with the axial moving core (4) and is used to trigger the opening and closing valve (8) to switch from the open state to the closed state when the axial moving core (4) is pushed back into the inner cavity of the tool tube (1) by pressure to the limit value.

2. The ultra-high voltage formation sealing grouting device for drilling operations according to claim 1, characterized in that: At least two sets of the sidewall guide holes (5) are provided. The two sets of sidewall guide holes (5) are arranged along the axial direction of the axial movable core (4). The number of grouting side holes (102) is the same as the number of sidewall guide holes (5) and the spacing is the same.

3. The ultra-high voltage formation sealing grouting device for drilling operations according to claim 2, characterized in that: The flow area of ​​the sidewall guide hole (5) is smaller than that of the central nozzle (6). The central nozzle (6) is used to output a mixture of slurry and activator during the large defect filling stage. The sidewall guide hole (5) uses local jet pressure to output high-pressure slurry during the microcrack penetration stage.

4. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The opening and closing valve (8) includes a valve seat and a movable plug that cooperates with the valve seat. The end of the linkage rod (9) is axially opposite to the movable plug. When the axially movable core (4) pushes back into the inner cavity of the tool tube (1), the linkage rod (9) pushes against the movable plug and moves to the sealing fit with the valve seat to cut off the supply of activator in the catalytic conduit (3).

5. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The tool tube (1) is also provided with a limiting cavity (103) that communicates with the grouting pre-hole (101). The outer wall of the axial movable core (4) is provided with a limiting ring (10). The elastic component (7) is located on the side of the limiting ring (10) away from the central nozzle (6). One end of the elastic component (7) abuts against the limiting ring (10), and the other end of the elastic component (7) abuts against the end wall of the limiting cavity (103).

6. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The grouting conduit (2) and the catalytic conduit (3) are respectively connected to one end of the mixing chamber (401) through the folded tube (11).

7. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 6, characterized in that: The mixing chamber (401) is located at one end of the axial movable core (4) facing the central nozzle (6). A guide tube (12) is also provided inside the axial movable core (4). The mixing chamber (401) is connected to each folded tube (11) through the guide tube (12).

8. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The front end of the axial movable core (4) is provided with a guide plate (13) for increasing the contact surface. The guide plate (13) is adapted to the front inclined surface of the tool tube body (1). The free end of the guide plate (13) is provided with a mudguard rubber strip (14). The free end of the mudguard rubber strip (14) abuts against the outer wall of the tool tube body (1).

9. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The elastic coefficient of the elastic component (7) is matched with the critical compaction back pressure of the soil and rock defects, and is used to set the logic threshold for the device to switch from high flow rate filling to high pressure splitting.

10. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The tool tube (1) is provided with an alloy scraper (15) on the side of its front end. The tool tube (1) is connected to a drive drilling machine for driving the tool tube (1) to rotate, which is used to clean the loose slag on the borehole wall in real time during the grouting process.

11. A grouting device for sealing and plugging ultra-high voltage formations in drilling operations according to claim 1, characterized in that: The inner wall of the tool tube (1) is provided with a trigger sensor (16). When the axial movable core (4) is pushed back to the limit value, it abuts against the trigger sensor (16) and sends the grouting compaction signal of that section to the ground control terminal.

12. A grouting method based on the apparatus according to any one of claims 1-11, characterized in that, Includes the following steps: S1: After forming a borehole by rotary drilling during drilling operations, the tool tube (1) is sent to the bottom of the well. S2: Start grouting. Under low back pressure, the axial moving core (4) is in the front position and the mixed grout containing activator is sprayed from the central nozzle (6) for anti-dilution filling, coagulation and reinforcement of lost formations or void defects. S3: As the back pressure increases after the defect is filled, the axial moving core (4) is pushed back, the catalyst conduit (3) is automatically closed and the side wall guide hole (5) is opened to spray slurry without activator. High pressure slurry is output in the micro-fracture of the well wall using a small cross-sectional area, while avoiding the activator from blocking the side wall guide hole (5). S4: After the ground control terminal receives the signal, the operator slowly withdraws the tool tube (1) and uses the grouting pressure difference to reinforce and repair the borehole wall in sections. Repeat the above steps S2-S3 until the entire hole and the gaps around the hole are filled.

13. The grouting method according to claim 12, characterized in that: In step S3 above, after the axial moving core (4) retracts and switches modes, the slurry maintains a long initial setting time in the microcracks due to the cessation of introducing the activator, and the dynamic pressure difference generated by the rotation of the device further increases the penetration radius of the slurry.

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