A device for cleaning the mud skin on the inner wall of a drill pipe

Abstract

The present invention provides a device for cleaning the mud skin on the inner wall of a drill pipe, which relates to the technical field of equipment for removing the mud skin on the inner wall of a drill pipe in wireline coring geological drilling, and solves the technical problems of easy failure of the seal of the cleaning device and complex structure. The device for cleaning the mud skin on the inner wall of a drill pipe includes an outer cylinder. The outer cylinder is of a hollow structure, sealed at the bottom, and has a main liquid flow channel for high-pressure liquid flow to pass through inside, and a liquid flow branch channel that is communicated with the main liquid flow channel and can branch and guide the high-pressure liquid flow; it also includes static nozzles and dynamic nozzles that are detachably arranged on the outer cylinder and communicated with the liquid flow branch channel to spray the high-pressure liquid flow onto the inner wall of the drill pipe; it further includes a swirl nozzle movably arranged inside the dynamic nozzle. Through the swirl nozzle, the high-pressure liquid flow can be ejected from the dynamic nozzle in a swirl form. The present invention has the characteristics of good cleaning effect, wider coverage, long service life and simple structure.

Description

Technical Field

[0001] The present invention relates to the technical field of equipment for removing mud skin on the inner wall of drill pipes in wireline coring geological drilling, and particularly relates to a device for cleaning the mud skin on the inner wall of drill pipes. Background Art

[0002] The emergence of wireline coring drilling technology is a major revolution in drilling technology. Its technical feature is that when taking core samples, it is not necessary to lift all the drill pipes in the borehole. Instead, a special fishing tool with a steel wire rope is used to fish the inner pipe containing the core to the surface through the center of the drill pipe and take out the core. With the current strategic shift of the focus of geological work in China, the exploration workload of unconventional energy sources such as shale gas and oil shale will continue to increase. Since the wireline coring drilling technology has a series of advantages such as reducing the auxiliary time of tripping, increasing the pure drilling time, and the more significant the economic effect for deeper boreholes; reducing the wear of drill pipe thread screwing and unscrewing, extending the service life of drill pipes, and reducing the consumption of pipe materials; reducing the wear of the bit during reaming, screwing and unscrewing, and the chance of collision with the borehole wall, extending the service life of the bit, etc., and can take out physical core samples to provide the most direct formation information for geological personnel, it has a crucial position in the exploration of unconventional energy sources - shale gas and oil shale.

[0003] However, during the process of wireline coring drilling, due to various reasons such as geological structure, drilling fluid composition, and drilling technology, mud skin often forms on the inner wall of the drill pipe. As the drilling time continues, the generation of mud skin will become more and more serious. When fishing the inner pipe assembly, it will cause the fishing tool to be unable to be normally inserted or the inner pipe assembly cannot be normally lifted to the surface after fishing, resulting in a several-fold increase in the fishing time of the inner pipe assembly, or breaking the steel wire rope connected to the fishing tool, triggering serious downhole accidents and causing serious economic losses. Therefore, solving the problem of mud skin formation on drill pipes is an important guarantee for giving full play to the advantages of wireline coring drilling technology. If the mud skin problem cannot be solved, it will greatly increase the auxiliary time of wireline coring drilling and the drilling cost will rise linearly.

[0004] Currently, the common treatment methods for solving mud skin formation on drill pipes are as follows: strictly controlling the solid content of the drilling fluid, adding surfactants to the drilling fluid to reduce the adsorption force between solid particles and the drill pipe, controlling the rotation speed, lengthening the length of the drilling fluid circulation tank, generally not less than 15m; setting up multiple sedimentation tanks to timely remove slag and replace the drilling fluid, etc. However, in the case of special formations such as self-sludging formations, with the continuation of drilling time, a large amount of mud skin will still accumulate on the inner wall of the drill pipe. Regardless of the above treatment methods, in the process of drilling under special working conditions, a large amount of mud skin will always accumulate on the inner wall of the drill pipe. Once this situation occurs, a technical solution with high cleaning efficiency, high cleaning degree, and convenience is urgently needed.

[0005] In order to remove the mud skin on the inner wall of the drill pipe when cleaning a special bottom layer, the existing technical solution is to install a nozzle in the middle and lower part of the inner wall of the drill pipe to spray high-pressure fluid. This jet can be used as a tool to clean the inner wall surface of the drill pipe and break the attached mud skin. The cleaning effect is mainly reflected in the impact force of the water jet on the attachments on the inner wall of the drill pipe. If the pressure of the water jet acting on the inner wall of the drill pipe is greater than the compressive strength of the mud skin attached to the inner wall surface of the drill pipe, the attached mud skin will be damaged and washed away by the high-pressure jet.

[0006] The applicant of the present invention has found that the existing technology has at least the following technical problems:

[0007] (1) The number and arrangement of the nozzles are unreasonable, and the ejected liquid is not enough to completely cover the inner wall of the drill pipe, resulting in incomplete cleaning; (2) The ejected fluid cannot form a good swirl, and cannot form continuous jet impacts, squeezes, water wedges and other cleaning effects on the mud skin attached to the inner wall of the drill pipe, and is not enough to efficiently clean the mud skin and let it return upward with the drilling fluid; (3) For the rotating nozzle, the seal will fail after long-term use, and the design structure for its precise rotating spraying is relatively complex and costly. Summary of the Invention

[0008] The purpose of the present invention is to provide a device for cleaning the mud skin on the inner wall of a drill pipe to solve the technical problems of easy seal failure and complex structure existing in the existing cleaning device.

[0009] To achieve the above purpose, the present invention provides the following technical solutions:

[0010] A device for cleaning the mud skin on the inner wall of a drill pipe provided by the present invention includes an outer cylinder. The outer cylinder is a hollow structure with a sealed bottom, and has a main liquid flow channel for high-pressure liquid flow to pass through inside, and a liquid flow branch channel that is communicated with the main liquid flow channel and can branch and guide the high-pressure liquid flow; it also includes static nozzles and dynamic nozzles that are detachably arranged on the outer cylinder and are communicated with the liquid flow branch channel to spray the high-pressure liquid flow onto the inner wall of the drill pipe; it further includes a swirl nozzle movably arranged inside the dynamic nozzle, through which the high-pressure liquid flow can be ejected from the dynamic nozzle in a swirl form.

[0011] On the basis of the above technical solutions, the present invention can be further improved as follows.

[0012] As a further improvement of the present invention, the liquid flow branch channel is divided into upper and lower layers, and each layer of the liquid flow branch channel is evenly arranged in a full circle along the circumferential direction of the outer cylinder. The central axis of each channel in the upper and lower layers forms an angle of 45° with the vertical direction. The horizontal projection intervals of the central axes of each channel in the upper layer are 60°, and the horizontal projection intervals of the central axes of each channel in the lower layer are 120°.

[0013] As a further improvement of the present invention, the static nozzle is located above the dynamic nozzle, and both the static nozzle and the dynamic nozzle are inclined downwardly. The number of static nozzles is six, and the number of dynamic nozzles is three. They are arranged vertically and offset from each other.

[0014] As a further improvement of the present invention, the static nozzle and the dynamic nozzle are screwed onto the outer cylinder.

[0015] As a further improvement of the present invention, the static nozzle includes a base cylindrical section, a contraction section, and an outlet rectifying section arranged in sequence; an external thread section for connecting with the outer cylinder is provided on the base cylindrical section; the taper θ of the contraction section is 12-14°; the ratio of the diameter a of the outlet end of the static nozzle to the diameter A of the inlet end is 0.5-0.6; the outlet rectifying section is a cylindrical structure, and its length is 3-4 times the diameter a of the outlet end of the static nozzle; a first bionic annular groove for reducing resistance and increasing speed is provided on the inner flow path surface of the static nozzle.

[0016] As a further improvement of the present invention, the first bionic annular groove is arranged in a full circle along the circumferential direction of the inner flow path surface of the static nozzle, and the number of the first bionic annular grooves is multiple, which are uniformly arranged along the axial direction of the static nozzle. The ratio range of the cutting depth d to the groove width w of the first bionic annular groove is 2-3; the ratio range of the groove center distance D to the groove width w of the first bionic annular groove is 2.5-5.

[0017] As a further improvement of the present invention, the dynamic nozzle includes a frustum-shaped bionic outer shell, a plate-shaped sealing ring, a flow dividing disc, a swirl nozzle, a bionic gasket, and an upper joint that are sequentially arranged in the bionic outer shell. The upper joint is screwed to the top end of the bionic outer shell and abuts against the plate-shaped sealing ring; both ends of the inner cavity of the upper joint are communicated with the liquid flow branch channel and the inner cavity of the flow dividing disc respectively; a liquid outlet for turning the liquid in its inner cavity by 90 degrees and outputting is provided on the side wall of the flow dividing disc, and an annular clamping groove for limiting and guiding one end of the swirl nozzle is arranged along the circumferential direction at the bottom of the flow dividing disc; a frustum-shaped clamping groove for limiting and guiding the other end of the swirl nozzle is arranged on the side of the bionic gasket facing the swirl nozzle. The swirl nozzle is inclined and eccentrically arranged between the flow dividing disc and the bionic gasket. The swirl nozzle is a cylindrical rod-shaped structure with a fluid cavity inside, and a strip-shaped water inlet is opened on its side wall. A water spraying port communicated with the water outlet of the bionic gasket is arranged at one end of the swirl nozzle close to the bionic gasket; second bionic convex bumps or second bionic concave pits for reducing resistance and increasing speed are uniformly arranged on the inner wall of the bionic outer shell; third bionic concave pits for reducing resistance and increasing speed are uniformly arranged on the inner wall of the frustum-shaped clamping groove of the bionic gasket; a fourth bionic annular groove for reducing resistance and increasing speed is provided on the surface of the fluid cavity of the swirl nozzle.

[0018] As a further improvement of the present invention, a hemispherical positioning ball is provided at one end of the swirl nozzle, the width and depth of the annular card slot are adapted to the specifications of the positioning ball, and the positioning ball and the annular card slot are in a point-plane contact structure; the other end of the swirl nozzle is a hemispherical structure, the specifications of the conical card slot are adapted to the specifications of the hemispherical end of the swirl nozzle, and the hemispherical end of the swirl nozzle and the conical card slot are in a plane-plane contact structure.

[0019] As a further improvement of the present invention, the fourth bionic annular groove is arranged in a whole circle along the circumference of the fluid cavity of the swirl nozzle, and the number of the fourth bionic annular grooves is multiple, and they are evenly arranged along the axial direction of the swirl nozzle. The ratio range of the cutting depth d to the groove width w of the fourth bionic annular groove is 2-3; the ratio range of the groove center distance D to the groove width w of the fourth bionic annular groove is 2.5-5.

[0020] As a further improvement of the present invention, the interior of the bionic housing is in a conical shape, and the second bionic convex bump, the second bionic concave pit or the third bionic concave pit are bionic non-smooth unit convex bumps or concave pits with the convex bumps on the body surface of the dung beetle as the biological prototype; the area of the second bionic convex bump and the second bionic concave pit accounts for 10%-60% of the inner wall area of the bionic housing; the area of the third bionic concave pit accounts for 40-60% of the inner wall area of the bionic washer; the specifications of the second bionic convex bump, the second bionic concave pit or the third bionic concave pit satisfy the mathematical model,

[0021] and

[0022] The present invention has the following beneficial effects compared with the prior art:

[0023] The device for cleaning the mud skin on the inner wall of a drill pipe provided by the present invention comprises an outer cylinder, a static nozzle and a dynamic nozzle; the inner walls of the static nozzle and the dynamic nozzle are both provided with a bionic non-smooth unit body for reducing drag and increasing speed; the static nozzle and the dynamic nozzle are sequentially installed on the upper and lower levels of the outer cylinder, the inner part of the outer cylinder is hollow and provided with a liquid flow channel, the main channel of the liquid flow channel presents a cylindrical contraction shape, and the branch channels of the liquid flow channel are divided into upper and lower levels; the angle between the central axis of each channel of the upper and lower levels and the vertical direction is 45°, the upper level is provided with 6 channels and the horizontal projection of the central axis of each channel is 60°, the lower level is provided with 3 channels and the horizontal projection of the central axis of each channel is 120°, and the upper and lower levels are staggered with each other; the high-pressure liquid flow passes through the upper and lower nozzles, and the high-pressure liquid sprayed by the static nozzle acts on the surface of the mud skin attached to the inner wall of the drill pipe, which has the effect of impacting, crushing, peeling and falling off the mud skin; the high-pressure liquid sprayed by the dynamic nozzle acts on the surface of the mud skin attached to the inner wall of the drill pipe, which has the effect of impacting , shearing, crushing, cavitation, grinding, peeling and shedding mud skin; the cleaning device provided by the present invention aims at the characteristics of the mud skin on the inner wall of the drill pipe with a wide adhesion surface and strong adhesion. Through the design of a two-stage dynamic and static coupled bionic nozzle, the limitations and constraints of the prior art are overcome, and the following beneficial effects will be played: ① The upper and lower dynamic and static nozzles act at the same time, and the lower dynamic nozzle can supplement and strengthen the cleaning of the upper static nozzle; ② The swirl ejected by the lower dynamic nozzle helps to improve the ability of the drilling fluid to carry cuttings, and better carry the shed mud skin out of the drill pipe; ③ The lower dynamic nozzle and the outer cylinder are fixedly threadedly connected, and the swirl ejection of the high-pressure liquid flow is realized through the internal swirl nozzle, which overcomes the shortcomings of the previous downhole rotary jet structure, high cost, and easy failure of bearings; ④ The force of the high-pressure fluid ejected by the two-stage nozzle on the mud skin attached to the inner wall of the drill pipe is more varied, which is conducive to the shedding of the mud skin; ⑤ The cleaning coverage is wider and the efficiency will be greatly improved. ⑥ The bionic structure has a simple design, excellent drag reduction effect, and can effectively improve the internal fluid properties and the friction resistance of the internal contact surfaces of components. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic diagram of the structure of the drilling rod inner wall mud cleaning device of the present invention after the dynamic and static nozzles are assembled;

[0026] Figure 2 This is an exploded view of the drilling rod inner wall mud cleaning device of the present invention;

[0027] Figure 3It is a working schematic diagram when the mud skin cleaning device for the inner wall of the drill pipe of the present invention is placed into the drill pipe;

[0028] Figure 4 It is a structural schematic diagram of the outer cylinder in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0029] Figure 5 It is a structural schematic diagram of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention.

[0030] Figure 6 It is a cross-sectional view of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0031] Figure 7 It is an exploded view of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0032] Figure 8 It is a structural diagram of the upper joint of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0033] Figure 9 It is a structural diagram of the bionic shell of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0034] Figure 10 It is a cross-sectional view of the bionic shell of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0035] Figure 11 It is a cross-sectional view of the movable nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0036] Figure 12 It is a schematic diagram of the mathematical model of the second bionic convex hull in the movable nozzle of the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0037] Figure 13 It is a structural diagram of the flow dividing plate in the movable nozzle of the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0038] Figure 14 is Figure 13 top view of;

[0039] Figure 15 is Figure 13 bottom view of;

[0040] Figure 16 It is a structural diagram of the swirl nozzle in the movable nozzle of the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0041] Figure 17 is Figure 16 cross-sectional view of;

[0042] Figure 18 is Figure 17 partially enlarged structural schematic diagram of;

[0043] Figure 19 It is the structural diagram of the bionic washer in the moving nozzle of the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0044] Figure 20 It is Figure 19 the sectional view of;

[0045] Figure 21 It is Figure 20 the partial enlarged structural schematic diagram of;

[0046] Figure 22 It is the schematic diagram of the mathematical model of the third bionic pit in the moving nozzle of the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0047] Figure 23 It is the structural schematic diagram of the static nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0048] Figure 24 It is the sectional view of the static nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention;

[0049] Figure 25 It is the schematic diagram of the specifications of each part of the static nozzle in the mud skin cleaning device for the inner wall of the drill pipe of the present invention.

[0050] In the figure: 1. Outer cylinder; 2. Static nozzle; 3. Moving nozzle; 4. Main liquid flow channel; 5. Upper liquid flow branch channel; 6. Lower liquid flow branch channel; 7. Upper joint; 8. Flat sealing ring; 9. Shunt plate; 10. Swirl nozzle; 11. Bionic washer; 12. Bionic housing; 13. Second bionic convex hull; 14. Liquid inlet; 15. Liquid outlet; 16. Annular clamping groove; 17. Positioning ball; 18. Water inlet; 19. Water spraying port; 20. Fourth bionic annular groove; 21. Third bionic pit; 22. Basic cylindrical section; 23. Contraction section; 24. Outlet rectifying section; 25. Unscrewing end; 26. First bionic annular groove; 100. Drill pipe. Detailed implementation manners

[0051] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other implementation manners obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope protected by the present invention.

[0052] Such as Figure 1 , Figure 2 and Figure 3As shown in the figure, the present invention provides a device for cleaning the mud skin on the inner wall of a drill pipe, which includes an outer cylinder 1. The outer cylinder 1 is a hollow structure with a sealed bottom and a hemispherical shape. High-pressure liquid flow enters from the top of the outer cylinder 1. It has a main liquid flow channel 4 for the high-pressure liquid flow to pass through and a liquid flow branch channel that communicates with the main liquid flow channel 4 and can branch and guide the high-pressure liquid flow. The main liquid flow channel 4 presents a cylindrical contraction shape. It also includes static nozzles 2 and dynamic nozzles 3 that are detachably arranged on the outer cylinder 1 and communicate with the liquid flow branch channel to spray the high-pressure liquid flow onto the inner wall of the drill pipe 100. It further includes a swirl nozzle 10 movably arranged inside the dynamic nozzle 3. Through the swirl nozzle 10, the high-pressure liquid flow can be sprayed out of the dynamic nozzle 3 in a swirling form.

[0053] As Figure 1 and Figure 4 shown in the figure, specifically, the liquid flow branch channels are divided into upper and lower layers, namely the upper liquid flow branch channel 5 and the lower liquid flow branch channel 6, and each layer of liquid flow branch channels is evenly arranged in a full circle along the circumferential direction of the outer cylinder 1.

[0054] As Figures 23 - 25 shown in the figure, the static nozzle 2 is located above the dynamic nozzle 3, and both the static nozzle 2 and the dynamic nozzle 3 are inclined downward. The number of upper liquid flow branch channels 5 is six, the central axis of each channel forms an angle of 45° with the vertical direction, and the horizontal projections of the central axes of each channel are spaced at 60°. The number of static nozzles 2 is six, which are sequentially connected to the six upper liquid flow branch channels 5. The number of lower liquid flow branch channels 6 is three, the central axis of each channel forms an angle of 45° with the vertical direction, and the horizontal projections of the central axes of each channel are spaced at 120°. The number of dynamic nozzles 3 is three, which are sequentially connected to the three lower liquid flow branch channels 6. The dynamic nozzles 3 and the static nozzles 2 are arranged in an offset manner up and down.

[0055] As Figure 2 shown in the figure, internal thread sections are provided on the outer cylinder 1 corresponding to the ends of the upper liquid flow branch channel 5 and the lower liquid flow branch channel 6, and external thread sections are provided at the corresponding positions of the static nozzles 2 and the dynamic nozzles 3. Both are screwed onto the outer cylinder 1 through threads.

[0056] As Figure 23 shown in the figure, as a further improvement of the present invention, the static nozzle 2 includes a basic cylindrical section 22, a contraction section 23, and an outlet rectifying section 24 arranged in sequence. An external thread section for connecting with the outer cylinder 1 is provided on the basic cylindrical section 22. The taper θ of the contraction section 23 is 12 - 14°. The ratio of the diameter a of the outlet end of the static nozzle 2 to the diameter A of the inlet end is 0.5 - 0.6. The outlet rectifying section 24 is a cylindrical structure with a length of 3 - 4 times the diameter a of the outlet end of the static nozzle 2. A first bionic annular groove 26 for reducing resistance and increasing speed is provided on the inner flow path surface of the static nozzle 2. For the convenience of grasping and loading and unloading, a screwing and removing end 25 is provided at the end of the outlet rectifying section 24 of the static nozzle 2, which is convenient for connecting and disassembling with the outer cylinder 1.

[0057] As Figure 24 and Figure 25 shown, further, the first bionic annular groove 26 is arranged in a full circle along the circumferential direction of the inner flow passage surface of the static nozzle 2, and the number of the first bionic annular grooves 26 is multiple, and they are uniformly arranged along the axial direction of the static nozzle 2. The ratio range of the cutting depth d to the groove width w of the first bionic annular groove 26 is 2-3; the ratio range of the groove center distance D to the groove width w of the first bionic annular groove 26 is 2.5-5.

[0058] As Figure 5 , Figure 6 and Figure 8 shown, as an alternative embodiment of the present invention, the moving nozzle 3 includes a frustum-shaped bionic outer shell 12, a plate-shaped sealing ring 8, a flow dividing disk 9, a swirl nozzle 10, a bionic gasket 11, and an upper joint 7 that are sequentially arranged in the bionic outer shell 12; both ends of the inner cavity of the upper joint 7 are respectively communicated with the liquid flow branch channel and the inner cavity of the flow dividing disk 9; as Figure 13 , Figure 14 shown, the bottom of the flow dividing disk 9 is sealed, and a liquid outlet 15 is arranged on the side wall for outputting the liquid in its inner cavity after turning it by 90 degrees. An inlet 14 is horizontally arranged inside the flow dividing disk 9. The number of the inlets 14 is two, and they are arranged in a relatively staggered manner. The inlet 14 is communicated with the outlet 15 for turning the high-pressure liquid flow entering the flow dividing disk 9 by 90 degrees and flowing out of the flow dividing disk 9 through the inlet 14 from the outlet 15. There is a gap between the flow dividing disk 9 and the bionic outer shell 12 for the high-pressure liquid flow to pass through; as Figure 7 , Figure 15 shown, a ring-shaped clamping groove 16 for limiting and guiding one end of the swirl nozzle 10 is arranged along the circumferential direction on the side of the bottom of the flow dividing disk 9 facing the swirl nozzle 10; the ring-shaped clamping groove 16 is arranged along the outer circle of the bottom of the flow dividing disk 9; as Figure 19 , Figure 20 and Figure 21 shown, a frustum-shaped clamping groove for limiting and guiding the other end of the swirl nozzle 10 is arranged on the side of the bionic gasket 11 facing the swirl nozzle 10. Specifically, the frustum-shaped clamping groove is located at the center of the bionic gasket 11. The swirl nozzle 10 is obliquely and eccentrically arranged between the flow dividing disk 9 and the bionic gasket 11. The swirl nozzle 10 is a cylindrical rod-shaped structure with a fluid cavity inside, and a strip-shaped water inlet 18 is opened on the side wall. One end of the swirl nozzle 10 close to the bionic gasket 11 is provided with a water spraying port 19 communicated with the water outlet of the bionic gasket 11; as Figure 9 and Figure 10 shown, second bionic convex bumps 13 or second bionic concave pits for reducing resistance and increasing speed are uniformly arranged on the inner wall of the bionic outer shell 12; third bionic concave pits 21 for reducing resistance and increasing speed are uniformly arranged on the inner wall of the frustum-shaped clamping groove of the bionic gasket 11; as Figure 17 and Figure 18As shown, a fourth bionic annular groove 20 for reducing drag and increasing speed is provided on the surface of the fluid chamber of the swirl nozzle 10.

[0059] As Figure 11 and Figure 16 shown, further, a hemispherical positioning ball 17 is provided at one end of the swirl nozzle 10. The width and depth of the annular card slot 16 are adapted to the specifications of the positioning ball 7, and the positioning ball 17 and the annular card slot 16 are in a point-to-plane contact structure to reduce the movement resistance. When the high-pressure liquid flows through the shunt plate 9 and enters the bionic housing 12, under the action of the liquid flow impact force, the swirl nozzle 10 rotates. The positioning ball 17 can move in the annular card slot 16, and the other end of the swirl nozzle 10 rotates in the conical card slot. The rotation of the swirl nozzle 10 forms a swirling high-pressure liquid flow, which is sprayed onto the inner wall of the drill pipe 100 in a swirling form for mud cake cleaning. The other end of the swirl nozzle 10 is a hemispherical structure. The specifications of the conical card slot are adapted to the specifications of the hemispherical end of the swirl nozzle 10, and the hemispherical end of the swirl nozzle 10 and the conical card slot are in a plane-to-plane contact structure.

[0060] As Figure 8 、 Figure 9 、 Figure 13 、 Figure 14 、 Figure 15 and Figure 16 shown, when the high-pressure liquid flow passes through the upper liquid flow branch channel 5, through the upper joint 7 of the moving nozzle 3, and enters the shunt plate 9; then the liquid flow enters from the liquid inlet 14 of the shunt plate 9 and sprays out from the liquid outlet 15 of the shunt plate 9, generating a swirl inside the bionic housing 12. The swirl generates a thrust on the eccentrically arranged swirl nozzle 10, causing it to rotate around the central axis. At the same time, the liquid flow enters the inside of the swirl nozzle 10 from the water inlet 18 of the swirl nozzle 10, passes through the fourth bionic annular groove 20 on the inner wall of the swirl nozzle 10, and finally sprays out from the water spray outlet 19 of the swirl nozzle 10.

[0061] Specifically, the fourth bionic annular groove 20 is provided in a full circle along the circumferential direction of the fluid chamber of the swirl nozzle 10, and the number of the fourth bionic annular grooves 20 is multiple, which are uniformly arranged along the axial direction of the swirl nozzle 10. The ratio range of the cutting depth d to the groove width w of the fourth bionic annular groove 20 is 2 - 3; the ratio range of the groove center distance D to the groove width w of the fourth bionic annular groove 20 is 2.5 - 5.

[0062] As Figure 12 and Figure 22As shown in the figure, as an alternative embodiment of the present invention, the interior of the bionic housing 12 is frustum-shaped. The second bionic convex hull 13, the second bionic concave pit or the third bionic concave pit 21 are bionic non-smooth unit convex hulls or concave pits with the convex hulls on the surface of the dung beetle as the biological prototype. The area of the second bionic convex hull 13 or the second bionic concave pit accounts for 10%-60% of the inner wall area of the bionic housing 12. The area of the third bionic concave pit 21 accounts for 40-60% of the inner wall area of the bionic washer 11. The specifications of the second bionic convex hull 13, the second bionic concave pit or the third bionic concave pit 21 satisfy the mathematical model, and The cross-sectional structure of the bionic non-smooth unit convex hull or concave pit has the following parameters: included angle θ, radius R, depth h, and width d.

[0063] During use, the high-pressure liquid flow passes through the internal channel of the outer cylinder 1 and is ejected from the static nozzle 2 and the dynamic nozzle 3. When the fluid ejected from the lower-level dynamic nozzle 3 impacts the mud cake attached to the inner wall of the drill pipe 100, the ejected fluid will decompose in two directions. The fluid in the normal direction forms a vertical extrusion impact on the mud cake, and the fluid in the radial direction forms a water wedge shearing effect on the mud cake. Under the comprehensive action of these two forces in all directions, the mud cake attached to the inner wall of the drill pipe can be efficiently and quickly cleaned. When the fluid ejected from the upper-level static nozzle 2 impacts the mud cake attached to the inner wall of the drill pipe 100, it can cause cracks in the attached mud cake layer. Subsequently, these fine cracks spread and develop. When the water wedge is formed, the mud cake layer attached to the inner wall of the drill pipe 100 will be broken. Through the interaction between the upper and lower static and dynamic nozzles, finally, the attached mud cake is peeled off and detached from the inner wall of the drill pipe 100, washed away from the surface of the inner wall of the drill pipe 100, and taken away with the drilling fluid circulation, achieving the effect of cleaning the mud cake. It can effectively solve the problems of incomplete cleaning, low cleaning efficiency, and complex cleaning process in the existing solutions and technologies when cleaning the mud cake attached to the inner wall of the drill pipe.

[0064] The working process of the present invention is as follows:

[0065] Suspend this nozzle into the drill pipe 100 in the borehole. The high-pressure liquid flow first passes through the main liquid flow channel 4 of the outer cylinder 1; then passes through the upper-level liquid flow branch channel 5 and the lower-level liquid flow branch channel 6, and jets out from the static nozzle 2 and the dynamic nozzle 3. When the liquid flow passes through the static nozzle 2 of the upper level, it successively passes through the basic cylindrical section 22, the contraction section 23, the outlet rectification section 24 and the internal first bionic annular groove 26; due to the excellent drag reduction effect of the first bionic annular groove and the ability to effectively improve the liquid flow characteristics inside the nozzle, the jet velocity of the liquid flow will increase, and it will have a good impact, crushing, peeling and falling-off effect on the mud cake adhering to the drill pipe 100; when the liquid flow passes through the dynamic nozzle 3 of the lower level, when the liquid successively passes through the liquid inlet 14 and the liquid outlet 15 of the flow dividing disc 9, a swirl will be generated inside the bionic housing 12, thereby driving the swirl nozzle 10 to perform eccentric rotation between the flow dividing disc 9 and the bionic gasket 11 inside the bionic housing 12. At the same time, the liquid flow will jet out from the water spraying orifice 19 of the swirl nozzle 10; because the swirl nozzle 10 is eccentrically arranged, the bionic non-smooth unit convex hull on the inner wall of the bionic housing 12 and the bionic non-smooth unit concave pit on the inner wall of the bionic gasket 11, the swirl nozzle 10 will perform eccentric rotation around the central axis; the bionic non-smooth unit convex hull and concave pit have excellent drag reduction effects and can effectively improve the liquid flow characteristics inside the nozzle, reducing the friction force between the swirl nozzle 10 and the inner wall of the bionic gasket 11; finally, it will have a good impact, shearing, crushing, cavitation, grinding, peeling and falling-off effect on the mud cake adhering to the drill pipe; in addition, when the double-stage dynamic and static coupling bionic nozzle works upward from the bottom of the drill pipe in the hole, the upper and lower dynamic and static nozzles act simultaneously, and the lower-level dynamic nozzle can play a supplementary and strengthening role in the cleaning of the upper-level static nozzle; the swirl jet ejected by the lower-level dynamic nozzle helps to improve the ability of the drilling fluid to carry cuttings and better carry the fallen mud cake out of the drill pipe; the lower-level dynamic nozzle overcomes the disadvantages of difficult control of the calculation accuracy of the previous downhole rotary jet technology and easy failure of the bearing; the high-pressure liquid flows ejected by the two-stage nozzles act on the mud cake adhering to the inner wall of the drill pipe in more variable force forms, which is conducive to the falling-off of the mud cake; the cleaning coverage is wider and the efficiency will be greatly improved.

[0066] Bionics is a comprehensive interdisciplinary subject that uses the mechanisms and laws discovered in the biological world to solve human needs. It uses the structure of natural biological systems and the process of life activities as the basis for technological innovation design and consciously imitates and replicates. Since its birth, bionics has developed rapidly and has achieved great achievements in many scientific research and technical engineering fields.

[0067] After billions of years of evolution and adaptation, organisms have formed surface morphologies and structural features that can coexist harmoniously with nature. That is, taking periodically arranged unit bodies as the basic units, and based on the technical foundations of non-smooth morphology, non-smooth structure, non-smooth chemistry, etc., multiple functions cooperate and couple to present the maximum adaptability to the natural environment. For example, soil animals such as earthworms, mole crickets, ants, dung beetles, and pangolins can move freely in and out of wet soil and sharp gravel without their body surfaces sticking to the soil at all. The leaf surfaces of plants such as lotus leaves and rice leaves can "remain unstained even when emerging from the sludge". It can be seen that non-smooth phenomena are widespread in nature. The so-called non-smooth surface here refers to a macroscopic surface on a parent body where at least one non-smooth effect exists or occurs along one-dimensional or multi-dimensional spaces. Geometric non-smooth features are presented on the body surfaces of soil animals such as earthworms, mole crickets, ants, dung beetles, and pangolins, that is, structural unit bodies of certain geometric shapes are randomly or regularly distributed on some parts of the body surface, and the shapes of the unit bodies include scale shapes, convex bump shapes, concave pit shapes, bristle shapes, and corrugated shapes, etc.

[0068] First of all, it should be noted here that "inward" is the direction towards the center of the accommodating space, and "outward" is the direction away from the center of the accommodating space.

[0069] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the Figure 1 orientation or positional relationship shown, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0070] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0071] In the present invention, unless otherwise clearly defined or limited, terms such as "installed", "connected", "joined", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In the present invention, unless otherwise clearly defined or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely means that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely means that the first feature has a lower horizontal height than the second feature.

[0073] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0074] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A device for cleaning the mud skin on the inner wall of a drill pipe, characterized in that, It includes an outer cylinder which is of a hollow structure with a sealed bottom, and has a main liquid flow channel inside for high-pressure liquid flow to pass through and a liquid flow branch channel communicating with the main liquid flow channel to branch and direct the high-pressure liquid flow; it also includes a static nozzle and a dynamic nozzle detachably arranged on the outer cylinder and communicating with the liquid flow branch channel to spray the high-pressure liquid flow onto the inner wall of the drill pipe; it further includes a swirl nozzle movably arranged inside the dynamic nozzle, through which the high-pressure liquid flow can be ejected from the dynamic nozzle in a swirl form; The liquid flow branch channels are arranged in upper and lower layers, and each layer of the liquid flow branch channels is evenly arranged in a full circle along the circumferential direction of the outer cylinder; The static nozzle is located above the dynamic nozzle, and both the static nozzle and the dynamic nozzle are inclined downward. The number of static nozzles is six, and the number of dynamic nozzles is three, and they are arranged in an upper and lower staggered manner; The static nozzle and the dynamic nozzle are screwed onto the outer cylinder; The static nozzle includes a basic cylindrical section, a contraction section, and an outlet rectifying section arranged in sequence; an external thread section for connecting with the outer cylinder is arranged on the basic cylindrical section; the taper θ of the contraction section is 12-14°; the ratio of the diameter a of the outlet end of the static nozzle to the diameter A of the inlet end is 0.5-0.6; the outlet rectifying section is of a cylindrical structure, and its length is 3-4 times the diameter a of the outlet end of the static nozzle; a first bionic annular groove for reducing resistance and increasing speed is arranged on the inner flow path surface of the static nozzle; The dynamic nozzle includes a frustum-shaped bionic outer shell, a plate-shaped sealing ring, a flow dividing disk, a swirl nozzle, a bionic washer, and an upper joint screwed to the top end of the bionic outer shell and abutting against the plate-shaped sealing ring, which are arranged in sequence inside the bionic outer shell; both ends of the inner cavity of the upper joint communicate with the liquid flow branch channel and the inner cavity of the flow dividing disk respectively; a liquid outlet for turning the liquid in its inner cavity by 90 degrees and outputting is arranged on the side wall of the flow dividing disk, and an annular card slot for limiting and guiding one end of the swirl nozzle is arranged along the circumferential direction at the bottom of the flow dividing disk; a frustum-shaped card slot for limiting and guiding the other end of the swirl nozzle is arranged on the side of the bionic washer facing the swirl nozzle. The swirl nozzle is inclined and eccentrically arranged between the flow dividing disk and the bionic washer. The swirl nozzle is of a cylindrical rod-like structure, has a fluid cavity inside, and strip-shaped water inlets are arranged on the side wall. A water spraying port communicating with the water outlet of the bionic washer is arranged at one end of the swirl nozzle close to the bionic washer; second bionic convex bumps or second bionic concave pits for reducing resistance and increasing speed are evenly arranged on the inner wall of the bionic outer shell; third bionic concave pits for reducing resistance and increasing speed are evenly arranged on the inner wall of the frustum-shaped card slot of the bionic washer; a fourth bionic annular groove for reducing resistance and increasing speed is arranged on the surface of the fluid cavity of the swirl nozzle.

2. The device for cleaning the mud skin on the inner wall of a drill pipe according to claim 1, characterized in that, The first bionic annular groove is arranged in a full circle along the circumferential direction of the inner flow path surface of the static nozzle, and the number of the first bionic annular grooves is multiple and evenly arranged along the axial direction of the static nozzle. The ratio range of the cutting depth d to the groove width w of the first bionic annular groove is 2-3; the ratio range of the groove center distance D to the groove width w of the first bionic annular groove is 2.5-5.

3. The device for cleaning the mud skin on the inner wall of a drill pipe according to claim 1, characterized in that, One end of the swirl nozzle is provided with a hemispherical positioning ball. The width and depth of the annular slot are adapted to the specifications of the positioning ball, and the positioning ball and the annular slot are in a point-surface contact structure. The other end of the swirl nozzle is a hemispherical structure. The specifications of the frustum-shaped slot are adapted to the specifications of the hemispherical end of the swirl nozzle, and the hemispherical end of the swirl nozzle and the frustum-shaped slot are in a surface-surface contact structure.

4. The device for cleaning the mud skin on the inner wall of a drill pipe according to claim 1, characterized in that, The fourth bionic ring groove is arranged in a full circle along the circumference of the fluid cavity of the swirl nozzle, and the number of the fourth bionic ring grooves is multiple, which are uniformly arranged along the axial direction of the swirl nozzle. The ratio range of the cutting depth d to the groove width w of the fourth bionic ring groove is 2-3. The ratio range of the groove center distance D to the groove width w of the fourth bionic ring groove is 2.5-5.

5. The device for cleaning the mud skin on the inner wall of a drill pipe according to claim 1, characterized in that, The interior of the bionic shell is in a frustum shape. The second bionic convex bump, the second bionic concave pit or the third bionic concave pit is a bionic non-smooth unit convex bump or concave pit with the convex bump on the surface of the dung beetle as the biological prototype. The area of the second bionic convex bump and the second bionic concave pit accounts for 10%-60% of the inner wall area of the bionic shell. The area of the third bionic concave pit accounts for 40-60% of the inner wall area of the bionic gasket. The specifications of the second bionic convex bump, the second bionic concave pit or the third bionic concave pit satisfy the mathematical model. and

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