A self-correcting direction acid jet drill bit

Abstract

The present invention provides a self-correcting direction acid jet drill bit, comprising: a pipe body, which includes a flexible pipe and a direction adjustment pipe, and the direction adjustment pipe can be turned relative to the flexible pipe; a fixing rib fixedly connected to the inner wall of the flexible pipe; an annular space flow adjustment device, the annular space flow adjustment device is fixedly connected to the fixing rib, and the annular space flow adjustment device is constructed in a cone shape, and includes a plurality of conical telescopic bodies connected in sequence; and a nozzle fixedly connected to the lower end of the annular space flow adjustment device; wherein, in a first state, the plurality of conical telescopic bodies are contracted, and the self-correcting direction acid jet drill bit can bend through a guide hole in a wellbore at a corresponding turning radius, thereby entering a reservoir for drilling; in a second state, the annular space flow adjustment device can make each conical telescopic body slide and stretch under the action of fluid pressure, and can make the fluid generate a pressure difference when the direction adjustment pipe encounters resistance and changes direction, so as to generate thrust on the direction adjustment pipe, thereby automatically adjusting the direction of the direction adjustment pipe.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas well completion, and particularly relates to a self-correcting direction acid jet drill bit, which is particularly suitable for a self-correcting direction acid jet drilling tool for fractured and fracture-cavity carbonate reservoirs. Background Art

[0002] With the continued growth of my country's oil consumption, its dependence on foreign oil imports has reached 72%. To meet my country's growing oil and energy needs while coping with the current complex international external environment and safeguarding its energy security, and given the irreversible decline in oil production from mature oil fields in central and eastern China, my country's oil exploration focus has shifted to deep and ultra-deep reservoirs. In recent years, most of my country's major onshore oil and gas discoveries have been located in fractured and fracture-vuggy carbonate reservoirs at depths exceeding 7,000 meters in northwest China. Due to current production and development technologies, all ultra-deep oil and gas wells exceeding 7,000 meters are single-bore wells, primarily using openhole completions.

[0003] Currently, due to limitations in geophysical exploration techniques, existing fracture-cavity identification technology can only identify larger fractures and caves in ultra-deep carbonate reservoirs. However, it cannot determine whether the fractures and caves within the reservoir contain crude oil or pure water. Furthermore, it is difficult to determine the exact location of small fractures and caves. Current challenges include the high cost of ultra-deep oil and gas well construction. If drilling into the reservoir results in significant losses, forcing the well to be completed, and encountering dry or water-filled holes can lead to wasted investment, or if drilling into a fracture-cavity with effective oil and gas resources fails to produce oil and gas after several years of production, the goal is to conduct low-cost sidetracking operations based on the previously drilled wellbore to open new oil and gas pathways or connect new oil and gas fractures and caves, thereby revitalizing the well.

[0004] However, at present, when a new well is completed after leakage and is a full water well or dry well, it is difficult to drill a new well in the open hole layer using a drilling rig because it is impossible to establish an effective circulation. If a casing window is opened in the casing section for sidetracking, given the depth of the well, ultra-deep casing window sidetracking is extremely difficult to engineer and the success rate is difficult to guarantee. If an old well that has been in production for several years needs to be re-sidetracked after pressure exhaustion, an ultra-deep well drilling rig will need to be re-used. The cost of sidetracking a well and the probability of encountering oil and gas are not as cost-effective as drilling a new well with a clear target, and its operating cost is relatively high.

[0005] The relatively inexpensive ultra-short radius radial horizontal well drilling technology currently relies primarily on a high-pressure jet drill bit connected to the front of a flexible hose. This not only uses a high-pressure water jet to break rock through the front nozzle, but also features a rearward-facing nozzle. The thrust generated by the rear nozzle propels the high-pressure water jet bit forward, thereby driving the rear flexible hose forward. However, this technology still has shortcomings. For example, it requires high water pressure for rock-breaking drilling. Conventional hydraulic transmission mainly uses continuous tubing, which has a relatively small diameter and results in high friction. Therefore, the current ultra-short radius radial horizontal well drilling technology is often used for wells shallower than 3,200 meters. Beyond 3,200 meters, wellhead pressure becomes excessive, creep distance becomes limited, and the engineering difficulty increases dramatically. On the other hand, its propulsion is mainly achieved through the reaction force generated by the back jet of the high-pressure jet drill bit. If the reservoir being drilled is heterogeneous or even has cracks, gaps and holes, several symmetrical back jets should be designed evenly. Because different reaction thrusts are generated or one of the back jets does not generate reaction thrust, the high-pressure jet drill bit will tilt, making it difficult to continue drilling, or its route will bend and the drilling trajectory will be uncontrolled.

[0006] Therefore, there is an urgent need for a self-correcting direction acid jet drill bit, which can assist rock breaking by acid pressurization, reduce the pressure value required for pure hydraulic rock breaking, and automatically correct the forward direction of the acid jet drill bit to achieve the function of automatic direction correction. Summary of the Invention

[0007] In response to the technical problems mentioned above, the present invention aims to propose a self-correcting directional acid jet drill bit, which can assist in rock breaking by acid pressurization, reduce the pressure value required for pure hydraulic rock breaking, and automatically correct the forward direction of the acid jet drill bit to achieve the function of automatic direction correction, so as to provide support and guarantee for ultra-deep well short radius drilling and radial horizontal well drilling, which is very beneficial to the stable production and increased production of ultra-deep carbonate reservoir oil fields.

[0008] To this end, the present invention provides a self-correcting directional acid jet drill bit, comprising: a pipe body comprising a flexible pipe and a direction adjustment pipe connected to the lower end of the flexible pipe, the flexible pipe being used to connect to an upper oil pipe and capable of turning relative to the flexible pipe; a fixing rib fixedly connected to the inner wall of the flexible pipe; an annular flow control device disposed within the pipe body, the upper end of the annular flow control device being fixedly connected to the fixing rib, the annular flow control device being conical and comprising a plurality of sequentially connected conical telescopic bodies; and a nozzle fixedly connected to the lower end of the annular flow control device. In a first state, the plurality of conical telescopic bodies are contracted, allowing the self-correcting directional acid jet drill bit to bend through a guide hole in a wellbore at a corresponding turning radius, thereby entering a reservoir for drilling. In a second state, the annular flow control device can cause each conical telescopic body to slide and stretch under the action of fluid pressure, and can generate a pressure differential in the fluid when the direction adjustment pipe encounters resistance and changes direction, thereby generating thrust on the direction adjustment pipe, thereby automatically adjusting the direction of the direction adjustment pipe.

[0009] In one embodiment, an inner jet channel space is formed inside the annular space flow regulating device.

[0010] In one embodiment, adjacent conical telescopic bodies are adaptively connected via the inclined sliding surface of the telescopic joint, and the adjacent conical telescopic bodies can be relatively telescopic via the inclined sliding surface of the telescopic joint.

[0011] In one embodiment, the outer wall surface of each of the conical telescopic bodies is formed as a first annular space flow control surface.

[0012] In one embodiment, a plurality of inner jet channel inlets are evenly distributed on the side wall of the conical telescopic body closest to the fixed rib, and the fluid from the flexible tube can enter the inner jet channel space from the inner jet channel inlets.

[0013] In one embodiment, a plurality of nozzles are provided in the nozzle head, and the fluid in the inner jet channel space can be ejected through the nozzles to perform jetting and rock breaking.

[0014] In one embodiment, the nozzle is a tapered hole nozzle whose diameter decreases from the inside to the outside, and a plurality of the nozzles are evenly distributed in the circumferential direction.

[0015] In one embodiment, the outer peripheral surface of the nozzle is formed as a second annular flow control surface, and the front end middle area of ​​the nozzle is configured as a plane.

[0016] In one embodiment, a first annular space is formed between the first annular flow control surface and the direction adjustment tube, and a second annular space is formed between the second annular flow control surface and the direction adjustment tube.

[0017] In the second state, when the direction adjustment tube encounters resistance and changes direction, the first annular space and the second annular space change, thereby generating a pressure difference in the fluid and generating a thrust on the direction adjustment tube.

[0018] In one embodiment, a steering ball is provided at the connection between the flexible tube and the direction-adjusting tube, so that the direction-adjusting tube can be turned relative to the flexible tube.

[0019] In one embodiment, the flexible pipe is a steel flexible pipe.

[0020] In one embodiment, a guide round head is provided at the front end of the direction adjustment tube.

[0021] Compared with the prior art, the advantages of this application are:

[0022] The self-correcting direction acid injection drill bit according to the present invention can transmit the driving force for the drill bit to move forward by connecting a semi-flexible steel pipe and then connecting an oil pipe. On the one hand, the rock breaking can be assisted by spraying acid liquid, thereby reducing the liquid pressure required for pure hydraulic rock breaking. On the other hand, the conventional hydraulic jet ultra-short radius radial horizontal well mainly adopts the self-propelled method of nozzle back-jet, and adopts a structure of front-jet hydraulic self-correcting acid injection drill bit forward direction. The design of the annular flow regulating conical telescopic body set on the rear end extension steel flexible pipe is based on the principle of the opposite change of flow velocity and pressure in the Bernoulli equation, which prompts the front end direction adjustment pipe to be automatically corrected by the acid flow, thereby achieving the function of automatic direction correction. The conical expansion body of the annular flow control device extends a certain distance beyond the pipe end and is retractable, offsetting the uncontrollable distance and volume of tubing runners. This provides a buffer space for compression, eliminating the need for separate tools such as a constant-speed controller for tubing runners. This significantly facilitates the drill bit's field application. Extending beyond the pipe creates space for the removal of some undissolved cuttings. Furthermore, the nozzle's flat working surface facilitates planar rock breaking. When the directional control tube encounters resistance at a certain point on the guide knob at its front end, this prevents changes in the tube's direction of advance and improves the drilling trajectory. The self-correcting directional acid jet drill bit provides the fundamental technical foundation for drilling ultra-short-radius radial horizontal wells in ultra-deep carbonate reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described below with reference to the accompanying drawings.

[0024] Figure 1 The structure of the self-correcting directional acid jet drill bit according to the present invention is schematically shown.

[0025] Figure 2 Schematically shows Figure 1 The initial state of the self-correcting directional acid jet drill bit is shown.

[0026] Figure 3 Schematically shows Figure 1 The self-correcting directional acid jet drill bit is shown at maximum extension.

[0027] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn to scale. DETAILED DESCRIPTION

[0028] The present invention will be described below with reference to the accompanying drawings.

[0029] In the present application, it should be noted that the end of the self-correcting directional acid injection drill bit lowered into the wellbore close to the wellhead is defined as the upper end, and the end away from the wellhead is defined as the lower end.

[0030] It should also be noted that the directional terms or qualifiers "upper", "lower", etc. used in this application are all directed to the attached drawings to which they are referred. Figure 1 They are not intended to define the absolute positions of the components involved, but may vary depending on the specific situation.

[0031] Figure 1 The structure of the self-correcting direction acid jet drill bit 100 according to the present invention is schematically shown. Figure 1 As shown, the self-correcting directional acid injection drill bit 100 includes a pipe body, a fixed rib 2, an annular flow regulating device 5, and a nozzle 9. The pipe body includes a flexible pipe 1 and a direction regulating pipe 14 connected to the lower end of the flexible pipe 1. The flexible pipe 1 is used to connect to the upper oil pipe (not shown), and the direction regulating pipe 14 can be turned relative to the flexible pipe 1. The fixed rib 2 is fixedly connected to the inner wall of the flexible pipe 1. The annular flow regulating device 5 is arranged inside the pipe body 1, and the upper end of the annular flow regulating device 5 is fixedly connected to the fixed rib 5. The annular flow regulating device 5 is constructed in a conical shape and includes a plurality of conical telescopic bodies 51 connected in sequence. The nozzle 9 is fixedly connected to the lower end of the annular flow regulating device 5.

[0032] According to the present invention, when the self-correcting direction acid jet drill bit 100 is actually working, in the initial state, the plurality of conical telescopic bodies 51 are in the contracted state (see FIG. Figure 2 In this state, the self-directed acid jet drill bit 100 is conducive to bending through the guide hole in the wellbore at a certain turning radius, thereby entering the reservoir for drilling operations. At this time, the self-directed acid jet drill bit 100 is in the first state.

[0033] When the flexible pipe 1 is connected to the long steel flexible pipe, which is then connected to the oil pipe at the wellhead, and acid is injected into the pipe to achieve a certain flow rate, the tapered expansion joints 51 of the annular flow control device 5 are subjected to fluid pressure and slide and stretch along the direction of the acid flow. When the direction control pipe 14 at the front end of the self-correcting direction acid injection drill bit 100 changes direction due to uneven surface resistance, large cracks, or other factors, the annular flow control device 5 can generate a pressure difference in the fluid to generate thrust on the direction control pipe 14, thereby automatically adjusting the direction of the direction control pipe 14. At this time, the self-correcting direction acid injection drill bit 100 is in the second state.

[0034] In one embodiment, the flexible pipe 1 is an extended steel flexible pipe. Figure 1 As shown, the extended steel flexible pipe serves as the rear half of the self-correcting directional acid jet drill bit 100, primarily used to connect the long steel flexible pipe and propel the self-correcting directional acid jet drill bit 100 forward. Simultaneously, the extended steel flexible pipe can transport acid and other fluids for rock-breaking drilling by the self-correcting directional acid jet drill bit 100.

[0035] According to one embodiment of the present invention, the retaining rib 2 is constructed as a hollow structure. Preferably, the retaining rib 2 has a symmetrical design. The radially outer wall of the retaining rib 2 is fixedly connected to the inner wall of the flexible pipe 1. The top tapered end of the annular flow control device 5 is fixedly connected to the center of the retaining rib 2. As a result, the annular flow control device 5 is initially aligned with the central axis of the flexible pipe 1.

[0036] According to the present invention, a steering ball 4 is provided at the connection between flexible tube 1 and steering tube 14, enabling steering tube 14 to steer relative to flexible tube 1. Steering ball 4 is fixedly connected to flexible tube 1, enabling steering tube 14, connected to the lower end of flexible tube 1, to be steerable. Steering ball 4 serves as both a connecting joint and an auxiliary steerable joint.

[0037] In one embodiment, a guide round head 12 may be provided at the front end of the direction adjustment tube 14 .

[0038] like Figure 1 As shown, a conical inner jet channel space 8 is formed within the annular flow control device 5. Adjacent conical telescopic bodies 51 are adapted to be connected via the inclined sliding surface 6 of the telescopic joint, enabling relative telescopic movement of the adjacent conical telescopic bodies 51. The outer wall of each conical telescopic body 51 forms a first annular flow control surface 7. A first annular space 15 is formed between the first annular flow control surface 7 and the direction adjustment tube 14.

[0039] There are several inner jet channel inlets 3 evenly distributed on the side wall of the conical telescopic body closest to the fixed rib 2, and the fluid from the flexible tube 1 can enter the inner jet channel space 8 through the inner jet channel inlets 3. The inner jet channel inlets 3 are evenly distributed in the circumferential direction and the axial direction. It should be noted that the conical telescopic body closest to the fixed rib 2 is Figure 1 The conical telescopic body at the uppermost end of the annular space flow regulating device 5 is the top cone.

[0040] According to the present invention, multiple nozzles 11 are provided within the nozzle head 9. Nozzles 11 are preferably throttling nozzles. Fluid within the inner jet channel space 8 can be ejected through nozzles 11 to achieve rock-breaking effects. Nozzles 11 utilize tapered orifices with a diameter that decreases from the inside outward. This structure accelerates the flowing fluid, forming a jet. By utilizing a stable fluid supply and a reduced flow area, nozzles 11 accelerate the outflowing fluid, achieving the effect of jet-assisted rock-breaking.

[0041] The nozzle 9 is a mid-plane nozzle with multiple nozzles 11 evenly distributed around the circumference, creating a uniform annular fluid flow. The front working surface (contact surface) 13 of the nozzle 9 is a flat structure, which facilitates planar rock breaking. When the direction adjustment tube 14 advances, if a certain part of the guide knob 12 at the front of the direction adjustment tube 14 encounters resistance, this prevents the tube 14 from changing its direction of propulsion, thereby improving the drilling trajectory.

[0042] like Figure 1 As shown, the outer peripheral surface of the nozzle 9 is formed as a second annular flow control surface 10, and a second annular space 16 is formed between the second annular flow control surface 10 and the direction adjustment tube 4. In the second state, when the direction adjustment tube 4 encounters resistance and changes direction, the first annular space 15 and the second annular space 16 change, thereby generating a pressure difference in the fluid, thereby generating thrust on the direction adjustment tube 4.

[0043] The following briefly describes the working process and principle of the self-correcting direction acid spray drill bit 100 according to the present invention. In the initial state, the self-correcting direction acid spray drill bit 100 has a plurality of conical telescopic bodies 51 in a contracted state (see FIG. Figure 2 In this state, the entire self-directional acid injection drill bit 100 is conducive to bending through the guide hole in the wellbore at a certain turning radius, thereby entering the reservoir to perform drilling operations.

[0044] When the flexible pipe 1 is connected to the long steel flexible pipe, and then connected to the oil pipe to the wellhead, and acid is injected into the pipe to form a certain flow rate, the several conical expansion bodies 51 of the annular flow regulating device 5 are subjected to the fluid pressure and slide and stretch along the flow direction of the acid. At this time, the annular flow regulating device 5 is in a semi-extended state (see Figure 1 ).

[0045] When the inlet area of ​​the inner jet channel inlet 3 is larger than the outlet area of ​​the nozzle 11 in the nozzle head 9, on the one hand, the liquid supply capacity of the inner jet channel space 8 can be made greater than the outlet capacity of the nozzle 11, thereby ensuring sufficient liquid supply. On the other hand, if the inlet area of ​​the inner jet channel inlet 3 is larger than the outlet area of ​​the nozzle 11, and the outlet area of ​​the nozzle 11 is smaller than the largest annular area occupied by the annular flow regulating device 5, the acid fluid will form a flow direction pressure on the annular flow regulating device 5. Since the annular flow regulating device 5 is fixed to the middle of the flexible pipe 1 by the fixing rib 2, when the direction of the flexible pipe 1 is determined, if the direction regulating tube 14 at the front end of the self-correcting direction acid jet drill bit 100 changes direction due to encountering non-balanced surface resistance, or large cracks, or other factors, Then the first annular space 15 between the first annular flow control surface 7 and the direction adjustment tube 14, and the second annular space 16 between the second annular flow control surface 10 and the direction adjustment tube 4 change. Based on the Bernoulli equation, the annular fluid flow rate on the side where the annular space becomes smaller is large and the pressure is small. At the same time, since the annular flow control device 5 is located in the middle, the fluid pressure difference generates thrust, which automatically causes the direction adjustment tube 14 to reverse and adjust the direction of the direction adjustment tube 14 automatically, so that the self-correcting directional acid jet drill bit 100 has the function of self-orientation without causing large deviations.

[0046] When the rock at the front end working surface (contact surface) 13 of the nozzle 9 is corroded by acid spray or washed away by the jet, the annular flow regulating device 5 can continue to extend until it is fully extended due to the difference in inlet and outlet areas of the nozzle 11 of the inner jet channel inlet 3 (see FIG. Figure 3 ). Thus, the front end working surface 13 of the nozzle 9 can extend outwards by a certain distance. This is conducive to breaking the rock in advance and is conducive to creating a space for discharging some undissolved rock cuttings. In addition, when the oil pipe is connected to the self-correcting direction acid jet drill bit 100 through the flexible pipe 1 for advancement, since the lower oil pipe is difficult to control the speed and small distance of the lowering, the front end working surface 13 of the nozzle 9 extends outwards by a certain distance, which is equivalent to leaving a buffer space for a certain compression distance. In this way, it is possible to avoid separately designing tools such as a constant speed controller for lowering the oil pipe, which is very conducive to the on-site construction application of the self-correcting direction acid jet drill bit 100.

[0047] In actual application, before operation, Figure 2 Assemble the self-correcting directional acid injection drill bit 100. The flexible pipe 1 is connected to the oil pipe via a long steel flexible pipe to the wellhead. The wellhead is then connected to a pump truck to pump acid into the pipe. Based on the acid etching time calculated in previous experiments, once the annular flow control device 5 has extended beyond the pipe, the tubing lowering speed is controlled to ensure the lowering stroke is less than the annular flow control device 5's extension stroke. Drilling continues in this manner until the target formation is reached. The tubing string is then either abandoned or removed, and production tubing can be lowered later.

[0048] The self-correcting direction acid jet drill bit 100 according to the present invention can transmit the driving force for the drill bit's advancement by connecting to a semi-flexible steel pipe, which is then connected to an oil pipe, and feeding the oil pipe downward. On the one hand, the injection of acid can assist in rock breaking, thereby reducing the liquid pressure required for pure hydraulic rock breaking. On the other hand, the conventional hydraulic jet ultra-short radius radial horizontal well, which mainly uses the nozzle back-jet self-propelled method, adopts a front-jet hydraulic self-correcting acid jet drill bit forward direction structure. The annular flow adjustment conical telescopic body is set in the rear end of the extended steel flexible pipe to align the design. Based on the principle of the Bernoulli equation that flow velocity and pressure change inversely, the front direction adjustment pipe is automatically corrected by the acid flow, achieving the function of automatic direction correction. At the same time, the conical telescopic body 51 of the annular flow regulating device 5 can extend a certain distance outside the pipe end and is flexible, which can offset the drawbacks of uncontrollable distance and uncontrollable amount of oil pipe during lowering. It can also leave a certain buffer space for compression distance, avoiding the need for separately designed tools such as a constant speed controller for lowering the oil pipe. This is very beneficial for promoting the on-site application of the drill bit. Moreover, extending outside the pipe helps create space for the discharge of some undissolved rock cuttings. In addition, the working surface 13 of the nozzle 9 is constructed as a planar structure, which is conducive to planar rock breaking. When the direction adjustment tube 14 is advanced, if a certain part of the guide round head 12 at the front end of the direction adjustment tube 14 encounters resistance, it can avoid changing the propulsion direction of the direction adjustment tube 14 and improve the drilling trajectory. The self-correcting directional acid injection drill bit 100 can provide the basic technical support for the drilling of ultra-short radius radial horizontal wells in ultra-deep carbonate reservoirs.

[0049] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0050] Furthermore, in the present invention, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, these terms may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0051] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0052] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation to the present invention. 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 replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A self-correcting direction acid jet drill bit, comprising: A pipe body, the pipe body comprising a flexible pipe (1) and a direction adjustment pipe (14) connected to the lower end of the flexible pipe, the flexible pipe being used to connect to an upper oil pipe, and the direction adjustment pipe being capable of turning relative to the flexible pipe; A fixing rib (2) fixedly connected to the inner wall of the flexible tube; an annular space flow regulating device (5) arranged in the pipe body, wherein the upper end of the annular space flow regulating device is fixedly connected to the fixed rib, and the annular space flow regulating device is constructed in a cone shape, comprising a plurality of conical telescopic bodies (51) connected in sequence; and A nozzle (9) fixedly connected to the lower end of the annular flow regulating device; In the first state, a plurality of the conical telescopic bodies are contracted, and the self-correcting direction acid jet drill bit can be bent through the guide hole in the wellbore at a corresponding turning radius, thereby entering the reservoir for drilling. In the second state, the annular space flow regulating device can make each of the conical telescopic bodies slide and stretch under the action of fluid pressure, and can make the fluid produce a pressure difference when the direction regulating tube encounters resistance and changes direction, so as to generate thrust on the direction regulating tube, thereby automatically adjusting the direction of the direction regulating tube.

2. The self-correcting directional acid jet drill bit according to claim 1, characterized in that: An inner jet channel space (8) is formed inside the annular space flow regulating device.

3. The self-correcting direction acid jet drill bit according to claim 2, characterized in that: Adjacent conical telescopic bodies are adaptively connected via the telescopic joint inclined sliding surface (6), and the adjacent conical telescopic bodies can be relatively telescopic via the telescopic joint inclined sliding surface.

4. The self-correcting direction acid jet drill bit according to claim 3, characterized in that: The outer wall surface of each of the conical telescopic bodies forms a first annular flow control surface (7).

5. The self-correcting direction acid jet drill bit according to claim 4, characterized in that: A plurality of inner jet channel inlets (3) are evenly distributed on the side wall of the conical telescopic body closest to the fixed rib, and the fluid from the flexible tube can enter the inner jet channel space from the inner jet channel inlets.

6. The self-correcting direction acid jet drill bit according to claim 5, characterized in that: A plurality of nozzles (11) are provided in the nozzle head, and the fluid in the inner jet channel space can be ejected through the nozzles to perform jetting and rock breaking.

7. The self-correcting direction acid jet drill bit according to claim 6, characterized in that: The nozzle is a tapered hole nozzle with a diameter decreasing from the inside to the outside, and a plurality of the nozzles are evenly distributed in the circumferential direction.

8. The self-correcting direction acid jet drill bit according to claim 6 or 7, characterized in that: The outer peripheral surface of the nozzle is formed as a second annular space flow control surface (10), and the front end working surface (13) of the nozzle is configured as a plane.

9. The self-correcting direction acid jet drill bit according to claim 8, characterized in that: A first annular space (15) is formed between the first annular flow control surface and the direction adjustment tube, and a second annular space (16) is formed between the second annular flow control surface and the direction adjustment tube. In the second state, when the direction adjustment tube encounters resistance and changes direction, the first annular space and the second annular space change, thereby generating a pressure difference in the fluid and generating a thrust on the direction adjustment tube.

10. The self-correcting direction acid jet drill bit according to claim 1, characterized in that: A steering ball (4) is provided at the connection between the flexible tube and the direction-adjusting tube, so that the direction-adjusting tube can be turned relative to the flexible tube.

11. The self-correcting direction acid jet drill bit according to claim 1 or 10, characterized in that: The flexible pipe is a steel flexible pipe.

12. The self-correcting directional acid jet drill bit according to claim 1 or 10, characterized in that: A guide round head (12) is provided at the front end of the direction adjustment tube.

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