Suction type reverse circulation icebreaking drill bit

Abstract

The invention provides a suction type reverse circulation icebreaking drill bit, which relates to the technical field of drilling equipment, and comprises a drill bit outer cylinder, a drill bit and a spiral flow generator, the drill bit comprises a drill bit body connected with the drill bit outer cylinder, a suction hole channel penetrating through the drill bit body in the axial direction of the drill bit outer cylinder, and a scraper cutting mechanism and an outer flow guide groove set which are arranged on the drill bit body in the circumferential direction of the suction hole channel. The spiral flow generator is arranged in the drill bit outer cylinder and connected with the drill bit in a circumferential limiting mode, an outer annular space is formed between the spiral flow generator and the drill bit outer cylinder, the outer annular space is communicated with the outer flow guide groove set, and the spiral flow generator comprises an inner channel communicated with the suction hole channel and an inner spraying hole set communicated with the inner channel and the outer annular space; the inner spraying hole sets are used for guiding airflow to generate the rotation effect. According to the invention, reverse circulation suction of ice chips can be realized, the technical defect of air positive circulation is overcome, disturbance to a well wall is further reduced, the ice chip migration efficiency is improved, and the risk that a drill bit is stuck is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling equipment, in particular to a suction type reverse circulation ice breaking drill bit. BACKGROUND

[0002] The polar region of the South Pole is rich in mineral resources, but due to the extremely cold climate conditions, the polar continent is covered with thick ice layers. These ice layers not only preserve rich historical, geographical and biological information, but also provide important basis for global climate change research. Carrying out polar ice layer drilling has important significance for exploring ancient biological life forms, revealing the formation and evolution mechanism of ice cover, understanding the geological environment under the ice, and evaluating the distribution of mineral resources under the ice. However, the harsh natural conditions of the polar region bring many challenges to ice layer drilling. The physical properties of the polar ice layer (such as temperature, density, strength, brittleness and hardness) are significantly different from ordinary rocks or minerals, which makes it difficult to directly apply traditional drilling technology. In addition, special protection measures and accident handling schemes need to be considered for ice layer drilling to ensure the safety of the operation and the reliability of the data. In terms of drilling technology, the air circulation drilling technology of the gas circulating medium has been widely used in the fields of geological core drilling, hydrological well drilling and foundation engineering construction due to its advantages of continuous coring sampling without tripping, preventing formation leakage, low gas consumption and the like. However, in the drilling of the polar ice layer, the use of air positive circulation drilling method has problems such as instability of the well wall, limitation of cuttings transport and ice sticking of the drill bit. These problems are caused by the large air gap in the snow layer and the temperature rise caused by the work of the gas, thereby affecting the drilling efficiency and safety. In contrast, the air reverse circulation drilling method effectively overcomes the technical drawbacks of air positive circulation by making the gas not flow through the annulus between the well wall and the drill pipe. The air reverse circulation drilling method has the advantages of easy control of circulation parameters, small well wall disturbance and high cuttings carrying efficiency, and provides a new solution for polar ice layer drilling. In the air reverse circulation drilling system, the drill bit is the core component of the bottom hole reverse circulation, and its structural design directly affects the gas flow rate and flow field characteristics, and plays a decisive role in the reverse circulation effect. Therefore, in view of the needs of polar ice layer drilling, it is necessary to design a reasonable drill bit structure to improve the ice breaking adaptability and ice cutting transport efficiency, which is a key problem to be solved for the air reverse circulation drilling method. SUMMARY

[0003] In order to overcome the above-mentioned defects of the prior art, the technical problem to be solved by the embodiments of the present application is to provide a suction type reverse circulation ice breaking drill bit for improving the ice breaking adaptability and ice cutting transport efficiency.

[0004] The above-mentioned purpose of the present application can be realized by adopting the following technical scheme. The present application provides a suction type reverse circulation ice breaking drill bit, comprising:

[0005] A drill bit outer cylinder;

[0006] A drill bit comprising a drill bit body connected with a drill bit outer cylinder, a suction channel penetrating through the drill bit body along an axial direction of the drill bit outer cylinder, and a scraper cutting mechanism and an outer flow guide groove group arranged on the drill bit body along a circumferential direction of the suction channel;

[0007] A spin generator arranged in the drill bit outer cylinder and connected with a drill bit circumferential limit, an external annulus formed between the spin generator and the drill bit outer cylinder, the external annulus being in communication with the outer flow guide groove group, the spin generator comprising an internal passage in communication with the suction channel, and an inner jet hole group in communication with the internal passage and the external annulus, the inner jet hole group being used to guide airflow to generate a rotating effect.

[0008] In a preferred embodiment of the present application, the inner jet hole group comprises a plurality of inner jet holes arranged on the spin generator in a spaced manner, the inner jet holes being deflected by a first preset angle relative to an axial direction of the spin generator, and the inner jet holes being deflected by a second preset angle relative to a circumferential direction of the spin generator.

[0009] In a preferred embodiment of the present application, the first preset angle is 60° to 80°, and the second preset angle is 10° to 30°.

[0010] In a preferred embodiment of the present application, the suction type reverse circulation ice breaking drill bit further comprises a stepped inner retraction structure arranged between a bottom of the drill bit body and the suction channel, the stepped inner retraction structure comprising a plurality of stepped annular surfaces arranged in a sequential manner and at an inclination, and the plurality of stepped annular surfaces being arranged in a retracted manner in a radial direction of the drill bit body from a bottom of the drill bit body to a top of the drill bit body.

[0011] In a preferred embodiment of the present application, the plurality of stepped annular surfaces comprises a first stepped annular surface, a second stepped annular surface, a third stepped annular surface, and a fourth stepped annular surface arranged in a sequential manner from a top of the drill bit body to a bottom of the drill bit body, an inclination angle of the first stepped annular surface relative to a horizontal plane is 50°±5°, an inclination angle of the second stepped annular surface relative to the horizontal plane is 20°±5°, an inclination angle of the third stepped annular surface relative to the horizontal plane is 90°±5°, and an inclination angle of the fourth stepped annular surface relative to the horizontal plane is 60°±5°.

[0012] In a preferred embodiment of the present application, the outer flow guide groove group comprises a plurality of outer flow guide grooves arranged on the drill bit body in a spaced manner, and each of the outer flow guide grooves is arranged on the second stepped annular surface.

[0013] In a preferred embodiment of the present application, a groove body of the outer flow guide groove is a straight line type groove structure penetrating through in an axial direction, which is more conducive to controlling the direction and speed of the gas fluid, and is beneficial to reducing the energy loss of the gas.

[0014] In a preferred embodiment of the present application, the scraper cutting mechanism comprises a plurality of outer cutters arranged on the drill bit body in a spaced manner, the bottom surface of the outer cutters is arranged obliquely towards the axis of the drill bit body, the oblique angle of the bottom surface of the outer cutters relative to the horizontal plane is 15° to 25°, and the cutting edge of the outer cutters is provided with serrated cutting notches.

[0015] In a preferred embodiment of the present application, the scraper cutting mechanism further comprises a diamond compact arranged on each of the outer cutters, the diamond compact is arranged on the outer circumferential side of the corresponding outer cutter, and at least part of the diamond compact protrudes from the corresponding outer cutter.

[0016] In a preferred embodiment of the present application, the inner wall of the drill bit outer cylinder is provided with an internal thread structure, the outer wall of the spinner is provided with an external thread structure, and the internal thread structure and the external thread structure are used for threadedly connecting the upper drill rod.

[0017] In a preferred embodiment of the present application, the outer wall of the drill bit outer cylinder is provided with a plurality of inverted eye notches arranged in a spaced manner; and / or, the outer wall of the drill bit outer cylinder is provided with a plurality of buckle removal grooves arranged in a spaced manner.

[0018] The technical scheme of the present application has the following remarkable beneficial effects:

[0019] The suction type reverse circulation ice breaking drill bit provided by the application is used in the following manner: the drill bit is arranged on the drill bit outer cylinder, the rotating device is coaxially arranged in the drill bit outer cylinder and connected with the drill bit in the circumferential direction, so that an external annulus is formed between the rotating device and the drill bit outer cylinder, the internal passage is arranged in the rotating device, and the internal passage is connected with the suction hole of the drill bit to form an internal annulus. During drilling, the suction type reverse circulation ice breaking drill bit is driven to rotate by the upper drill rod, and the ice rock can be cut and broken by the cutter cutting mechanism on the drill bit. Meanwhile, the high-pressure airflow is input into the external annulus, the high-pressure airflow can flow to the outer guide groove group and the internal jet hole group along the external annulus, part of the high-pressure airflow enters the internal passage of the rotating device through the internal jet hole group, the internal jet hole group can be used to guide the airflow to generate a rotating effect, so that a high-speed low-pressure area is formed in the internal passage, and the internal passage is connected with the suction hole of the drill bit, so that a strong suction effect can be generated on the space at the bottom of the drill bit. Moreover, the remaining high-pressure airflow is sprayed to the bottom of the drill bit along the outer guide groove group, and the high-pressure airflow sprayed through the outer guide groove group can disturb the broken ice chips, so that the ice chips at the bottom of the drill bit can be quickly sucked into the internal passage and discharged. The suction type reverse circulation ice breaking drill bit can realize reverse circulation suction of the ice chips by cooperation of the external annulus, the internal passage, the outer guide groove group and the internal jet hole group, the technical defects of the air positive circulation are overcome, the disturbance to the well wall is reduced, the ice chip migration efficiency is improved, and the risk of the drill bit being stuck is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor under the premise of these drawings.

[0021] The drawings described herein are for illustrative purposes only, and are not intended to limit the scope of the present application in any way. In addition, the shape and scale of the components in the drawings are only illustrative, and are used to help understand the present application, and are not specific to the shape and scale of the components of the present application. Those skilled in the art can select various possible shapes and scales to implement the present application according to specific circumstances under the guidance of the present application.

[0022] Figure 1 The three-dimensional structure schematic diagram of one embodiment of the suction type reverse circulation ice breaking drill bit provided by the application;

[0023] Figure 2 The explosion structure schematic diagram of one embodiment of the suction type reverse circulation ice breaking drill bit provided by the application;

[0024] Figure 3A cross-sectional structural schematic diagram of an embodiment of the suction type reverse circulation ice breaking drill bit according to the present application;

[0025] Figure 4 A three-dimensional structural schematic diagram of an embodiment of the drill bit according to the present application;

[0026] Figure 5 A three-dimensional structural schematic diagram of an embodiment of the spin generator according to the present application;

[0027] Figure 6 A three-dimensional structural schematic diagram of an embodiment of the drill bit outer cylinder according to the present application;

[0028] Figure 7 A structural schematic diagram of an embodiment of the first positioning groove and the second positioning groove according to the present application;

[0029] Figure 8 A radial direction cross-sectional structural schematic diagram of an embodiment of the spin generator according to the present application.

[0030] Reference signs of the above drawings:

[0031] 10, external annulus;

[0032] 20, internal annulus;

[0033] 100, drill bit outer cylinder; 110, inverted eye flange; 120, unthreading groove; 130, second connecting block;

[0034] 200, drill bit; 210, drill bit body; 220, scraper cutting mechanism; 221, outer cutter head; 222, bottom surface of the outer cutter head; 223, sawtooth cutting notch; 224, diamond compact; 230, outer flow guide groove; 240, stepped inner retraction structure; 241, first step annulus; 242, second step annulus; 243, third step annulus; 244, fourth step annulus; 250, first positioning groove; 260, second positioning groove;

[0035] 300, spin generator; 310, inner jet hole; 320, first connecting block. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0037] Please refer to Figures 1 to 8As shown, the embodiment of the present application provides a suction type reverse circulation ice breaking drill bit, which comprises a drill bit outer cylinder 100, a drill bit 200 and a spinner 300, the drill bit 200 comprises a drill bit body 210 connected with the drill bit outer cylinder 100, a suction hole channel penetrating through the drill bit body 210 along the axial direction of the drill bit outer cylinder 100, and a scraper cutting mechanism 220 and an outer guide groove group arranged on the drill bit body 210 along the circumferential direction of the suction hole channel; the spinner 300 is arranged in the drill bit outer cylinder 100 and connected with the circumferential limit of the drill bit 200, and an external annulus 10 is formed between the spinner 300 and the drill bit outer cylinder 100, the external annulus 10 is connected with the outer guide groove group, and the spinner 300 comprises an internal passage connected with the suction hole channel and an inner jet hole group connected with the internal passage and the external annulus 10, and the inner jet hole group is used for guiding the airflow to generate a rotating effect.

[0038] As a whole, as shown in the embodiments of Figure 1 、 Figure 2 and Figure 3 , the drill bit 200 in the suction type reverse circulation ice breaking drill bit is arranged on the drill bit outer cylinder 100, and the spinner 300 is coaxially arranged in the drill bit outer cylinder 100 and connected with the circumferential limit of the drill bit 200, so that the external annulus 10 can be formed between the spinner 300 and the drill bit outer cylinder 100, the internal passage is arranged in the spinner 300, and the internal passage is connected with the suction hole channel of the drill bit 200 to form an internal annulus 20.

[0039] During drilling, the suction type reverse circulation ice breaking drill bit is driven to rotate by the upper drill rod, and the scraper cutting mechanism 220 on the drill bit 200 can cut and crush the ice rock. At the same time, the high-pressure airflow is input into the external annulus 10, the high-pressure airflow can flow along the external annulus 10 to the outer guide groove group and the inner jet hole group, part of the high-pressure airflow enters the internal passage of the spinner 300 through the inner jet hole group, the inner jet hole group can be used for guiding the airflow to generate a rotating effect, so that a high-speed low-pressure area is formed in the internal passage, and the internal passage is connected with the suction hole channel on the drill bit 200, so that a strong suction effect can be generated on the space at the bottom of the drill bit 200.

[0040] And the remaining part of the high-pressure airflow is sprayed along the outer guide groove group to the bottom of the drill bit 200, the high-pressure airflow sprayed through the outer guide groove group can disturb the crushed ice chips, so that the ice chips at the bottom of the drill bit 200 can be quickly sucked into the internal passage and discharged.

[0041] The suction type reverse circulation ice breaking drill bit of the present application cooperates the external annulus 10, the internal annulus 20, the outer guide groove group and the inner jet hole group, so that the ice chips can be sucked and circulated in reverse, the technical defects of air positive circulation are overcome, the disturbance to the well wall is reduced, the ice chip migration efficiency is improved, and the risk of the drill bit 200 being stuck is reduced.

[0042] In the embodiment of the present application, the radial dimension of the drill bit outer cylinder 100 is the same as that of the drill bit body 210, and the drill bit outer cylinder 100 is coaxially connected with the drill bit body 210, so that the drill bit outer cylinder 100 and the drill bit body 210 can constitute a full-hole drilling tool combination mechanism, which is beneficial to increase the space of the gas flow channel and enhance the overall gas tightness of the drilling tool.

[0043] Further, a flow guide structure can be arranged at the lower part of the inner wall of the drill bit outer cylinder 100, which is used to guide the gas flow to the inner jet hole group. The flow guide structure can improve the distribution of the gas flow and help to improve the swirl uniformity of the inner jet hole group. The specific structure of the flow guide structure can be adjusted according to the use requirement, which is not specifically limited herein.

[0044] In an available embodiment, a plurality of trapezoidal gas flow guide blocks are arranged at the lower part of the inner wall of the drill bit outer cylinder 100 in a circumferential distribution and staggered arrangement, and the plurality of trapezoidal gas flow guide blocks correspond to the positions of the inner jet hole group of the swirler 300.

[0045] In the embodiment of the present application, the mounting mode of the swirler 300 can be adjusted according to the use requirement, which is not specifically limited herein. In an available embodiment, the swirler 300 is coaxially arranged inside the drill bit outer cylinder 100, and the swirler 300 is connected with the drill bit body 210 by welding. The internal passage of the swirler 300 is connected with the suction channel of the drill bit 200, and the internal passage and the suction channel constitute the internal annulus 20, and the external annulus 10 is formed between the swirler 300 and the drill bit outer cylinder 100.

[0046] In the embodiment of the present application, as shown in the embodiments of Figure 5 , Figure 6 and Figure 7 , at least one first connecting block 320 is arranged at the bottom of the swirler 300, and a first positioning groove 250 matched with the first connecting block 320 is arranged on the top surface of the drill bit body 210, and the first connecting block 320 is inserted into the first positioning groove 250, so as to play a positioning and circumferential limiting role, and ensure the mounting precision between the swirler 300 and the drill bit body 210.

[0047] Further, at least one second connecting block 130 is arranged at the bottom of the drill bit outer cylinder 100, and a second positioning groove 260 matched with the second connecting block 130 is arranged on the top surface of the drill bit body 210, and the second connecting block 130 is inserted into the second positioning groove 260, so as to play a positioning and circumferential limiting role, and ensure the mounting precision between the drill bit outer cylinder 100 and the drill bit body 210.

[0048] In the embodiment of the present application, as shown in Figure 3 and Figure 5In the shown embodiment, the inner nozzle group comprises a plurality of inner nozzles 310 arranged in a ring on the spinner 300, the inner nozzles 310 are axially deflected by a first preset angle a and circumferentially deflected by a second preset angle β relative to the spinner 300.

[0049] The designer can adjust the number and arrangement of the inner nozzles 310 according to the needs of use, which is not specifically limited here. For example, the inner nozzles 310 are provided in six, and the six inner nozzles 310 are arranged in a ring.

[0050] The high-pressure gas can enter the inner annulus 20 from the outer annulus 10 through the inner nozzles 310, thereby forming a high-speed low-pressure annulus region in the inner annulus 20. The plurality of inner nozzles 310 can generate strong suction force through the spinning effect, which is beneficial to promote the transport of ice chips to the inner annulus 20.

[0051] In addition, the inner nozzles 310 are arranged in a spiral shape by being axially deflected by a first preset angle a and circumferentially deflected by a second preset angle β, which is beneficial to guide the airflow to produce a rotating effect, and thereby can form a negative pressure region at the bottom of the drill bit 200, thereby enhancing the suction force.

[0052] Through the suction effect, the ice chips at the bottom of the drill bit 200 can be effectively sucked into the inner annulus 20, and the transport efficiency of the ice chips is accelerated in cooperation with the airflow disturbance generated by the outer flow guide groove 230.

[0053] Further, the designer can adjust the shape, number and arrangement of the inner nozzles 310 according to the needs of use, which is not specifically limited here.

[0054] In a feasible embodiment, the cross-sectional shape of the inner nozzle 310 is oval. In other feasible embodiments, the cross-sectional shape of the inner nozzle 310 can also be set to circular, polygonal or other shapes.

[0055] In the embodiment of the present application, as shown in Figure 3 and Figure 8 In the shown embodiment, the first preset angle a is 60° to 80°, and the second preset angle β is 10° to 30°. Preferably, the first preset angle a is 70°, and the second preset angle β is 20°.

[0056] By axially deflecting the inner nozzle 310 by 70°, when the high-pressure gas enters the inner annulus 20 through the inner nozzle 310, the high-pressure gas can generate a rotating airflow in the axial direction, thereby strengthening the rotating effect of the airflow, which is beneficial to improve the suction force and promote the effective transport of ice chips.

[0057] And, by making the inner nozzle hole 310 circumferentially deflect 20°, it is ensured that the gas flow forms a uniform rotational flow when entering the inner annulus 20, avoiding the problem of unstable gas flow, so that the gas flow and ice chips can be fully mixed, ensuring the smoothness of the transportation of ice chips.

[0058] The inner nozzle hole 310 in the present application is designed with double deflection in the axial and circumferential directions, which not only enhances the rotating effect of the spinner 300, but also significantly improves the transportation efficiency of ice chips through negative pressure and suction. Compared with conventional inner nozzle holes 310 or straight-line nozzles, the present application can more efficiently combine gas flow and ice chips, improve the suction capacity of the drill bit 200, reduce ice chip accumulation, and ensure efficient operation during drilling.

[0059] In an embodiment of the present application, as shown in the embodiment shown in Figure 2 and Figure 4 The suction type reverse circulation ice breaking drill bit further comprises a stepped inner collection structure 240 arranged between the bottom of the drill bit body 210 and the suction channel, the stepped inner collection structure 240 comprising a plurality of stepped ring surfaces arranged in sequence and inclined, and arranged in the radial direction of the drill bit body 210 towards the inside in the direction from the bottom of the drill bit body 210 to the top of the drill bit body 210.

[0060] By covering the bottom space of the drill bit 200 with the multi-stage stepped inner collection structure 240, the energy loss of high-pressure gas can be reduced, which is conducive to the accumulation of ice chips inside the drill bit 200, reducing the leakage, and further the ice chips can quickly enter the inner annulus 20 under the action of suction, improving the ice chip transportation efficiency.

[0061] In a feasible embodiment, as shown in the embodiment shown in Figure 4 The plurality of stepped ring surfaces comprise a first stepped ring surface 241, a second stepped ring surface 242, a third stepped ring surface 243 and a fourth stepped ring surface 244 arranged in sequence in the direction from the top of the drill bit body 210 to the bottom of the drill bit body 210, the inclination angle of the first stepped ring surface 241 relative to the horizontal plane is 50°±5°, the inclination angle of the second stepped ring surface 242 relative to the horizontal plane is 20°±5°, the inclination angle of the third stepped ring surface 243 relative to the horizontal plane is 90°±5°, and the inclination angle of the fourth stepped ring surface 244 relative to the horizontal plane is 60°±5°.

[0062] Preferably, the inclination angle of the first stepped ring surface 241 relative to the horizontal plane is approximately 50°, the inclination angle of the second stepped ring surface 242 relative to the horizontal plane is approximately 20°, the inclination angle of the third stepped ring surface 243 relative to the horizontal plane is approximately 90°, and the inclination angle of the fourth stepped ring surface 244 relative to the horizontal plane is approximately 60°.

[0063] The four stepped ring surfaces are of different angles and play different technical roles, and cooperatively solve the problems in the ice chip migration process.

[0064] Specifically, the first stepped ring surface 241 aims to optimize the preliminary guidance of the gas flow, reduce gas waste and improve energy utilization efficiency. The angle, in cooperation with the space at the bottom of the drill bit 200, ensures that the gas flow remains stable when entering the next stage of the stepped structure, avoiding excessive diffusion or instability of the gas flow.

[0065] The second stepped ring surface 242 is used to accurately guide the flow of ice chips, preventing the ice chips from diffusing disorderly under the action of the gas flow, and ensuring that the ice chips effectively enter the internal annular space 20 area.

[0066] The third stepped ring surface 243 aims to stabilize the gas flow and reduce the deviation of the gas flow in the transmission process, ensuring that the ice chips can stably enter the next stage.

[0067] The fourth stepped ring surface 244 is used to enhance the mixing efficiency of the gas flow and the ice chips, ensuring that the gas flow does not cause the aggregation of the ice chips during the migration of the ice chips.

[0068] Through precise angle design and orderly cooperation, the problems of ice chip leakage, ice chip aggregation, and unstable gas flow in existing structures are effectively solved, greatly improving the transportation efficiency of the ice chips and the utilization efficiency of the gas energy.

[0069] Unlike the conventional diffuser groove in the prior art, the four-stepped inward-retraction structure 240 in the present application, through precise angle design and gas flow guidance, not only reduces gas leakage, but also ensures that the ice chips can be more efficiently and stably sucked into the internal annular space 20, optimizes the effect of high-pressure gas assisting ice chip migration, and reduces the risk of the drill being stuck by ice chips.

[0070] Of course, in other feasible embodiments, the designer can adjust the number and inclination angle of the stepped ring surfaces according to the needs of use, which is not specifically limited here.

[0071] In the embodiments of the present application, the outer flow guide groove group includes a plurality of outer flow guide grooves 230 arranged on the drill bit body 210 in the form of a spacer ring, and each outer flow guide groove 230 is arranged on the second stepped ring surface 242. The designer can adjust the number and arrangement position of the outer flow guide grooves 230 according to the needs of use, which is not specifically limited here.

[0072] In a feasible embodiment, as shown in FIG. 6, the outer flow guide groove group includes a plurality of outer flow guide grooves 230 arranged on the drill bit body 210 in the form of a spacer ring, and each outer flow guide groove 230 is arranged on the second stepped ring surface 242. Figure 3 and Figure 7In the shown embodiment, three outer flow guide grooves 230 are arranged in axial spaced rings around the drill bit body 210.

[0073] The high pressure gas flowing through the outer flow guide grooves 230 forms high speed gas and is ejected from the lower end surface of the drill bit body 210, which plays a role of disturbing and breaking ice chips and helps to assist ice chip migration.

[0074] Preferably, the groove body of the outer flow guide groove 230 is a straight linear groove structure that is axially through, which is more conducive to controlling the direction and speed of the gas flow and is beneficial to reduce the energy loss of the gas.

[0075] In the embodiment of the present application, the outer flow guide groove 230 is arranged as a straight cylinder structure, and the outer flow guide groove 230 penetrates the drill bit body 210 and is parallel to the axis of the drill bit body 210, which helps to shorten the gas flow path and greatly retains the gas energy.

[0076] In use, the high pressure gas enters the outer flow guide groove 230 through the outer annulus 10 and is ejected at high speed along the outer flow guide groove 230 to the bottom of the drill bit 200. The high pressure gas flow ejected through the outer flow guide groove 230 can disturb the ice chips and be reflected upward from the suction hole of the drill bit body 210.

[0077] The outer flow guide groove 230 can better disturb the bottom ice chips, improve the ice chip and gas mixing efficiency, reduce the risk of ice chip accumulation at the bottom of the drill bit 200, and the outer flow guide groove 230 also reduces the amount of gas leakage from the bottom space of the drill bit 200 by cooperating with the stepped inward structure 240 of the drill bit body 210, thereby improving the efficiency of the gas assisting ice chip migration.

[0078] The designer can adjust the width of the outer flow guide groove 230 according to the use needs, which is not specifically limited here. In a feasible embodiment, the width of the outer flow guide groove 230 is about 4mm, and the central angle thereof is about 60°.

[0079] By setting the width of the outer flow guide groove 230 to be about 4mm, high flow rate gas can be formed to better disturb the ice chips, and the high speed gas can also clean the bottom of the drill bit 200 and reduce the temperature of the drill bit 200.

[0080] In the embodiment of the present application, as shown in Figure 2 and Figure 4 The scraper cutting mechanism 220 includes a plurality of outer cutting heads 221 arranged in spaced rings on the drill bit body 210, the bottom surface 222 of the outer cutting head is arranged obliquely towards the axis of the drill bit body 210, the inclination angle of the bottom surface 222 of the outer cutting head relative to the horizontal plane is 15° to 25°, and the cutting edge of the outer cutting head 221 is provided with a serrated cutting notch 223.

[0081] The designer can adjust the number and arrangement of the outer cutters 221 according to the use requirement, which is not specifically limited herein. For example, three outer cutters 221 are arranged. In addition, the outer diameter size of the scraper cutting mechanism 220 can be the same as the wellbore size, so as to guarantee the drilling effect.

[0082] Further, the designer can adjust the size and structure of the sawtooth cutting notch 223 according to the use requirement, which is not specifically limited herein. By arranging the sawtooth cutting notch 223 on the outer cutter 221, the ice breaking effect is significantly improved.

[0083] Preferably, the size of the sawtooth cutting notch 223 is according to the PDC bit PDC tooth arrangement principle, which is beneficial to realize the method migration and improve the ice breaking efficiency. The PDC (Polycrystalline Diamond Compact) bit is a high-efficiency bit widely used in the fields of oil, natural gas and geological exploration, and the core component is a PDC cutting tooth.

[0084] In the embodiment of the present application, as shown in the embodiment, Figure 4 The scraper cutting mechanism 220 further comprises a diamond compact 224 arranged on each outer cutter 221. The diamond compact 224 is arranged on the outer circumferential side of the corresponding outer cutter 221, and at least part of the diamond compact 224 protrudes from the corresponding outer cutter 221.

[0085] By embedding the diamond compact 224 on the outer cutter 221, the wear resistance of the outer cutter 221 is further improved by using the diamond compact 224, so as to prolong the service life of the outer cutter 221 and guarantee the ice breaking effect. The designer can adjust the specific shape and structure of the diamond compact 224 according to the use requirement, which is not specifically limited herein.

[0086] In the embodiment of the present application, the inner wall of the drill bit outer cylinder 100 is provided with an internal thread structure, and the outer wall of the reamer 300 is provided with an external thread structure. The internal thread structure and the external thread structure are used for threadedly connecting the upper drill rod. The designer can adjust the specific arrangement position of the internal thread structure and the external thread structure according to the use requirement, which is not specifically limited herein.

[0087] In the embodiment of the present application, as shown in the embodiment, Figure 1 and Figure 6 The outer wall of the drill bit outer cylinder 100 is provided with a plurality of inverted eye notches 110 arranged at intervals; and / or, the outer wall of the drill bit outer cylinder 100 is provided with a plurality of buckle release grooves 120 arranged at intervals.

[0088] Preferably, the outer wall of the drill bit outer cylinder 100 is provided with a plurality of inverted eye notching ridges 110 at intervals.

[0089] In an embodiment, the upper outer wall of the drill bit outer cylinder 100 is provided with three inverted eye notching ridges 110 at intervals.

[0090] Furthermore, the cross section of the inverted eye notching ridge 110 is generally trapezoidal, and the rotary cutting effect is formed by the inverted eye notching ridge 110 during the rotation of the drill tool, effectively reducing the friction between the drill bit 200 and the formation contact surface, and reducing the risk of sticking.

[0091] Further, the outer wall of the drill bit outer cylinder 100 is provided with two unloading grooves 120 at intervals, which facilitates disassembly and assembly operations and improves the convenience of operation.

[0092] The present application is based on the efficient breaking of ice layer by the scraper cutting mechanism 220, combined with the air reverse circulation suction structure, so as to complete the breaking of ice layer and the migration of ice chips.

[0093] Furthermore, the high-speed low-pressure area can be formed in the internal annulus 20 through the inner jet hole 310, so as to form a strong suction effect on the bottom space of the drill bit 200.

[0094] The high-speed gas sprayed by the outer flow guide groove 230 can disturb the ice chips, and by cooperating with the multi-stage stepped inner collecting structure 240 on the drill bit body 210, it is beneficial to the ice chip aggregation at the bottom of the drill bit 200, and reduces the energy loss of high-pressure gas.

[0095] The broken ice chips can finally enter the internal annulus 20 through the suction effect, so as to realize the reverse circulation migration function of the ice chips. The drill tool has better ice breaking adaptability, reduces the well wall disturbance, and improves the ice chip migration efficiency and drilling speed.

[0096] All articles and references, including patent applications and publications, disclosed herein are hereby incorporated by reference for all purposes. The term "consisting essentially of to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements, ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the term "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also is taken to mean that other elements, ingredients, components or steps are optional, and the use of the term "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also is taken to mean that other elements, ingredients, components or steps are optional, and that statements of

[0097] The various embodiments in the specification are described in progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be mutually referred. The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A suction-type reverse circulation ice-breaking drill bit, characterized in that, include: Drill bit outer casing; The drill bit includes a drill bit body connected to the outer cylinder of the drill bit, a suction channel penetrating the drill bit body along the axial direction of the outer cylinder of the drill bit, and a scraper cutting mechanism and an outer guide groove assembly arranged circumferentially on the drill bit body along the suction channel. A swirl starter is disposed in the outer cylinder of the drill bit and is circumferentially connected to the drill bit. An outer annulus is formed between the swirl starter and the outer cylinder of the drill bit. The outer annulus is connected to the outer guide channel group. The swirl starter includes an internal channel connected to the suction channel and an inner nozzle group connecting the internal channel and the outer annulus. The inner nozzle group is used to guide the airflow to generate a rotation effect.

2. The suction-type reverse circulation ice-breaking drill bit as described in claim 1, characterized in that, The internal spray hole group includes a plurality of internal spray holes spaced apart and arranged in a ring on the swivel starter. The internal spray holes are deflected axially relative to the swivel starter by a first preset angle and circumferentially deflected relative to the swivel starter by a second preset angle.

3. The suction-type reverse circulation ice-breaking drill bit as described in claim 2, characterized in that, The first preset angle is 60° to 80°, and the second preset angle is 10° to 30°.

4. The suction-type reverse circulation ice-breaking drill bit as described in claim 1, characterized in that, The suction-type reverse circulation ice-breaking drill bit also includes a stepped inward structure disposed between the bottom of the drill bit body and the suction channel. The stepped inward structure includes multiple stepped annular surfaces that are connected in sequence and inclined. Along the direction from the bottom to the top of the drill bit body, the multiple stepped annular surfaces are arranged to contract inward in the radial direction of the drill bit body.

5. The suction-type reverse circulation ice-breaking drill bit as described in claim 4, characterized in that, The plurality of stepped annular surfaces include a first stepped annular surface, a second stepped annular surface, a third stepped annular surface, and a fourth stepped annular surface arranged sequentially along the direction from the top to the bottom of the drill bit body. The first stepped annular surface has an inclination angle of 50°±5° relative to the horizontal plane, the second stepped annular surface has an inclination angle of 20°±5° relative to the horizontal plane, the third stepped annular surface has an inclination angle of 90°±5° relative to the horizontal plane, and the fourth stepped annular surface has an inclination angle of 60°±5° relative to the horizontal plane.

6. The suction-type reverse circulation ice-breaking drill bit as described in claim 5, characterized in that, The external guide groove group includes multiple external guide grooves spaced around the drill bit body, and each of the external guide grooves is disposed on the second step ring surface.

7. The suction-type reverse circulation ice-breaking drill bit as described in claim 1, characterized in that, The scraper cutting mechanism includes a plurality of outer cutters spaced around the drill bit body. The bottom surface of the outer cutter is inclined toward the axis of the drill bit body, and the inclination angle of the bottom surface of the outer cutter relative to the horizontal plane is 15° to 25°. The cutting edge of the outer cutter is provided with a serrated cutting notch.

8. The suction-type reverse circulation ice-breaking drill bit as described in claim 7, characterized in that, The scraper cutting mechanism further includes diamond composite sheets disposed on each of the outer cutter heads. The diamond composite sheets are disposed on the outer peripheral edge of the corresponding outer cutter head, and at least a portion of the diamond composite sheets protrude from the corresponding outer cutter head.

9. The suction-type reverse circulation ice-breaking drill bit as described in claim 1, characterized in that, The inner wall of the drill bit outer cylinder is provided with an internal thread structure, and the outer wall of the swivel is provided with an external thread structure. The internal thread structure and the external thread structure are used to thread the upper drill rod.

10. The suction-type reverse circulation ice-breaking drill bit as described in claim 1, characterized in that, The outer wall of the drill bit outer cylinder is provided with a plurality of truncated rhombuses for reaming; and / or, the outer wall of the drill bit outer cylinder is provided with a plurality of shackle grooves.

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