Rotary valve near-bit synergistic rock-breaking drilling tool

Abstract

The present application belongs to the technical field of oil and gas drilling, and particularly relates to a rotary valve type near-bit rock breaking and enhancing drilling tool, aiming to solve the problems that the existing drilling speed increasing tools have certain applicable conditions, have many limiting factors, and have high drilling speed increasing difficulty. The drilling tool comprises a drilling tool body, a rotating block arranged in the drilling tool body, a fixed block, and a power device for driving the rotating block to rotate; the upper end surface of the fixed block is attached to the lower end surface of the rotating block, the rotating block is provided with a first flow channel penetrating through the upper and lower portions, and the fixed block is provided with a second flow channel penetrating through the upper and lower portions; during the rotation of the rotating block, the first flow channel and the second flow channel always have an overlapping portion, and the cross-sectional area of the overlapping portion periodically and alternately changes. The present application has a simple structure, produces a "wave band type" high frequency impact on the bottom hole rock, assists in breaking the bottom hole rock, eliminates the adverse effects caused by the pressure holding effect, improves the rock breaking effect of the drill bit and the mechanical drilling speed, improves the return of the bottom hole cuttings, and ensures the safety of the drilling operation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas drilling, and particularly relates to a rotary valve type near-bit synergistic rock breaking drilling tool. BACKGROUND

[0002] In the process of oil and gas exploration and development drilling, the liquid column pressure generated by the drilling fluid is generally higher than the formation pore pressure, so as to prevent the formation fluid from entering the well, thus ensuring the safety of drilling operation, but at the same time, it will also have a pressure holding effect on the bottom hole rock. The pressure holding effect increases the difficulty of breaking the formation rock, making it more difficult for the drill bit to cut and break the rock. On the other hand, it leads to difficulty in returning the bottom hole cuttings, which easily causes repeated breaking of the cuttings, low drilling mechanical drilling speed, and difficulty in judging the formation lithology, resulting in long drilling cycle and high operation cost. Especially in deep formation drilling, in order to balance the formation pressure, higher density drilling fluid needs to be used, and the pressure holding effect is more obvious, and it is difficult to increase the drilling speed. The use of underbalanced drilling can solve many adverse effects caused by the pressure holding effect, but underbalanced drilling requires a large amount of manpower, equipment, and high cost, which is difficult to be widely applied.

[0003] In addition, in order to further improve the drilling mechanical drilling speed, the commonly used measure is to connect a power motor above the drill bit, and rely on the high speed of the motor to improve the rock breaking effect of the drill bit and improve the mechanical drilling speed. However, with the increasing proportion of deep wells and complex structure wells, the speed increasing effect realized by simply relying on the power motor cannot meet the production demand. The series of speed increasing tools currently appeared in the industry all have certain applicable conditions, and there are many limiting factors, especially the types of speed increasing drilling tools that can be used near the drill bit are less, and the speed increasing effect of the rotary steering tool is obvious, but the cost is high and the application range is limited. SUMMARY

[0004] The present application provides a rotary valve type near-bit synergistic rock breaking drilling tool to alleviate the problem that the existing drilling speed increasing tools all have certain applicable conditions, many limiting factors, and high drilling speed increasing difficulty.

[0005] In order to alleviate the above technical problems, the technical scheme provided by the present application is as follows:

[0006] A rotary valve type near-bit synergistic rock breaking drilling tool comprises a drilling tool body, a rotating block arranged in the drilling tool body, a fixed block, and a power device for driving the rotating block to rotate; the upper end surface of the fixed block is attached to the lower end surface of the rotating block, the rotating block is provided with a first flow channel penetrating up and down, and the fixed block is provided with a second flow channel penetrating up and down; during the rotation of the rotating block, the first flow channel and the second flow channel always have an overlapping part, and the cross-sectional area of the overlapping part periodically alternates.

[0007] Further, the first flow channel comprises two symmetrically arranged circular-arc first openings and a circular-arc second opening connecting the two first openings, the area of the second opening is smaller than that of the first opening, and the first and second openings are coaxially arranged with the power device; the second flow channel comprises two symmetrically arranged circular-arc third openings, and the third openings and the first openings correspond one by one in the initial state.

[0008] Further, the drill tool body comprises a coaxially arranged and screw-connected upper joint and lower joint, the outer side upper part of the upper joint is provided with an external thread, and the inner side lower part of the lower joint is provided with an internal thread; the inner side of the lower joint is provided with a first step, and the lower part of the fixed block abuts against the first step.

[0009] Further, the power device comprises a fixed turbine and a rotating turbine rotatably connected to the lower part of the fixed turbine, the upper part of the fixed turbine is connected to the inner wall of the upper part of the upper joint, and the lower part of the rotating turbine is fixedly connected to the rotating block.

[0010] Further, the fixed turbine comprises an inner body, a support ring coaxially arranged with the inner body, a support block connecting the support ring and the inner body, and fixed impeller blades spirally distributed on the outer side of the inner body from top to bottom; a gap is arranged between the support ring and the inner body; the inner side of the upper joint is provided with a second step, the middle part of the second step is provided with a first groove, a ring-shaped retainer ring is inserted into the first groove, the support ring abuts against the second step, and the lower end of the support ring abuts against the retainer ring.

[0011] Further, the rotating turbine is provided with an upper body; the outer diameter of the upper end of the upper body is equal to the length of the outer diameter of the inner body, a plurality of rotating impeller blades are spirally distributed on the outer side of the upper end of the upper body from top to bottom, and the rotating direction of the rotating impeller blades is opposite to that of the fixed impeller blades; the outer diameter of the upper body gradually increases from the middle part to the bottom.

[0012] Further, the rotating turbine further comprises a lower body arranged below the upper body; an inner hole penetrating up and down is arranged in the lower body, and the inner hole extends upward to the bottom of the upper body, a plurality of radial through holes are uniformly distributed on the upper part of the lower body, and the through holes communicate with the inner hole; the outer diameter of the top surface of the lower body is equal to the length of the outer diameter of the bottom surface of the upper body, and the section of the lower body provided with the through holes gradually increases in outer diameter from top to bottom.

[0013] Further, the lower inner wall of the lower body is provided with a third step, and the rotating block is arranged in interference fit with the third step; the lower outer wall of the lower body is rotatably connected with the upper joint through a limiting connecting piece.

[0014] Further, a fourth step is arranged on the inner wall of the lower part of the upper joint, and a fifth step is arranged on the outer wall of the lower part of the rotating turbine; the limiting connecting piece comprises a limiting ring abutting against the fourth step, a gasket arranged below the limiting ring, a first outer bearing sleeve mounted on the inner wall of the limiting ring, and a first inner bearing sleeve mounted on the outer wall of the fifth step; the upper end surface of the lower joint abuts against the lower end surface of the gasket, so that the limiting ring and the gasket are fixed on the fourth step.

[0015] Further, the inner wall of the lower joint is provided with a sixth step, and the sixth step is located at the lower part of the first step; the lower part of the fixed block is provided with a flow guide block, and the flow guide block abuts against the sixth step; the flow guide block is provided with an inner cavity penetrating from top to bottom, the middle upper part of the inner cavity is a variable diameter hole with a diameter gradually decreasing from top to bottom, the lower part of the inner cavity is a small flow hole with a fixed diameter, and the inner cavity is communicated with the inner hole through the overlapping part of the first flow channel and the second flow channel.

[0016] The beneficial effect analysis of the rotating valve type near-bit synergistic rock breaking drilling tool in the application is as follows:

[0017] The rotating valve type near-bit synergistic rock breaking drilling tool comprises a drilling tool body, a rotating block arranged in the drilling tool body, a fixed block, and a power device for driving the rotating block to rotate; the upper end surface of the fixed block is attached to the lower end surface of the rotating block, the rotating block is provided with a first flow channel penetrating from top to bottom, and the fixed block is provided with a second flow channel penetrating from top to bottom; during the rotation of the rotating block, the first flow channel and the second flow channel always have an overlapping part, and the cross-sectional area of the overlapping part periodically and alternately changes.

[0018] During normal drilling, the drilling fluid flows out of the drilling tool body through the overlapping part of the first flow channel and the second flow channel and enters the drill bit; as the power device drives the rotating block to rotate, the cross-sectional area of the overlapping part of the first flow channel and the second flow channel periodically and alternately changes, so that the drilling fluid flowing out of the drill bit nozzle has obvious and alternate changes in flow rate, and a pulsed jet is generated, an intensity fluctuation is formed on the surface of the rock, and the rock is damaged under the action of instantaneous tensile stress and fatigue damage under the action of alternating stress; in addition, during the process in which the flow rate of the drilling fluid at the drill bit instantaneously decreases, a transient negative pressure is formed on the surface of the rock at the bottom of the well, and the cuttings formed by the drill bit are sucked away from the bottom of the well, so that the cuttings are prevented from being repeatedly cut at the bottom of the well. The application generates a "waveband type" high-frequency impact on the rock at the bottom of the well, assists in breaking the rock at the bottom of the well, eliminates the adverse effects of the pressure holding effect, improves the rock breaking effect of the drill bit and the rate of penetration, improves the return of the cuttings at the bottom of the well, and ensures the safety of the drilling operation. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the related art description. Obviously, the drawings described below are only some of the embodiments of the present application, and all the other drawings obtained by those of ordinary skill in the art without creative work based on these drawings are within the protection scope of the present application.

[0020] Figure 1 The structure schematic diagram of the rotary valve type near-bit synergistic rock breaking drilling tool provided by the embodiment of the present application is provided.

[0021] Figure 2 The top view structure schematic diagram of the fixed turbine provided by the embodiment of the present application is provided.

[0022] Figure 3 The top view structure schematic diagram of the rotating block provided by the embodiment of the present application is provided.

[0023] Figure 4 The top view structure schematic diagram of the fixed block provided by the embodiment of the present application is provided.

[0024] Icon:

[0025] 1-upper joint; 2-fixed turbine; 201-internal body; 202-supporting block; 203-supporting ring; 204-fixed impeller blade; 3-retaining ring; 4-second inner bearing sleeve; 5-second outer bearing sleeve; 6-rotary turbine; 601-rotary impeller blade; 602-through hole; 603-inner hole; 604-upper body; 605-lower body; 7-first inner bearing sleeve; 8-first outer bearing sleeve; 9-limiting ring; 10-gasket; 11-rotating block; 1101-first opening; 1102-second opening; 12-fixed block; 1201-third opening; 13-flow guiding block; 14-lower joint; 15-first step; 16-second step; 17-third step; 18-fourth step; 19-fifth step; 20-sixth step. DETAILED DESCRIPTION

[0026] The technical solutions of the present application will be described clearly and completely below in combination with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, and all the other embodiments obtained by those of ordinary skill in the art without creative work based on these drawings are within the protection scope of the present application.

[0027] In the description of the present application, it should be pointed out that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance. Physical quantities in the formula, such as no separate marking, should be understood as the basic quantity of the International System of Units, or the derived quantity derived from the basic quantity by multiplication, division, differentiation or integration, etc. Mathematical operations.

[0028] In the description of the present application, it should be pointed out that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0029] In the process of oil and gas exploration and development drilling, the liquid column pressure generated by the drilling fluid is generally higher than the formation pore pressure, so as to prevent the formation fluid from entering the well, thus ensuring the safety of drilling operation, but at the same time, it will also have a pressure holding effect on the bottom hole rock. The pressure holding effect increases the difficulty of breaking the formation rock, making it more difficult for the drill bit to cut and break the rock. On the other hand, it leads to difficulty in returning the bottom hole debris, which is easy to cause repeated crushing of the debris, low drilling speed of the drilling machinery, and difficulty in judging the formation lithology, resulting in long drilling cycle and high operation cost. Especially in deep formation drilling, in order to balance the formation pressure, higher density drilling fluid is required, and the pressure holding effect is more obvious, and the drilling speed is difficult to improve. The use of underbalanced drilling can solve many adverse effects caused by pressure holding effect, but underbalanced drilling requires a large investment in manpower and equipment, and the cost is high, which is difficult to be widely applied.

[0030] In addition, in order to further improve the drilling speed of the drilling machinery, the commonly used measure is to connect a power motor above the drill bit, which can improve the rock breaking effect of the drill bit and improve the mechanical drilling speed by relying on the high speed of the motor. However, with the increasing proportion of deep wells and complex structure wells, the speed improvement effect achieved by relying solely on the power motor cannot meet the production demand. The series of speed improvement tools currently appeared in the industry all have certain application conditions and many limiting factors, especially the types of speed improvement tools that can be used near the drill bit are less, and the speed improvement effect of the rotary steering tool is obvious, but the cost is high and the application range is limited.

[0031] In view of the above, the present application provides a rotary valve type near-bit synergistic rock breaking drilling tool, please refer to Figures 1 to 4 The drilling tool comprises a drilling tool body, a rotating block 11, a fixed block 12 and a power device for driving the rotating block 11 to rotate, which are arranged in the drilling tool body; the upper end surface of the fixed block 12 is attached to the lower end surface of the rotating block 11; the rotating block 11 is provided with a first flow channel penetrating from top to bottom; the fixed block 12 is provided with a second flow channel penetrating from top to bottom; during the rotation of the rotating block 11, the first flow channel and the second flow channel always have an overlapping part, and the cross-sectional area of the overlapping part periodically and alternately changes.

[0032] More preferably, the fixed block 12 and the rotating block 11 are both made of alloy, which has high hardness and strong corrosion resistance.

[0033] During normal drilling, the drilling fluid flows out of the drilling tool body through the overlapping part of the first flow channel and the second flow channel and enters the drill bit; as the power device drives the rotating block 11 to rotate, the cross-sectional area of the overlapping part of the first flow channel and the second flow channel periodically and alternately changes; therefore, the drilling fluid flowing out of the drill bit nozzle has obvious and alternating changes in flow rate, which produces a pulsed jet flow, forms a pressure fluctuation on the surface of the rock, and causes the rock to be damaged under the action of instantaneous tensile stress and fatigue damage under the action of alternating stress; in addition, during the process of instantaneous decrease in the flow rate of the drilling fluid at the drill bit, a transient negative pressure is formed on the surface of the bottom hole rock, and the cuttings formed by the drill bit are sucked away from the bottom hole, avoiding repeated cutting of the cuttings at the bottom hole, significantly improving the rate of penetration, and ensuring the safety of drilling operations.

[0034] The shape and structure of the first flow channel and the second flow channel are described in detail in Figure 3 and Figure 4 , as follows:

[0035] The first flow channel comprises two symmetrically arranged circular-arc-shaped first openings 1101 and a circular-arc-shaped second opening 1102 connecting the two first openings 1101, the area of the second opening 1102 is smaller than that of the first opening 1101, and the first opening 1101 and the second opening 1102 are coaxially arranged with the power device; the second flow channel comprises two symmetrically arranged circular-arc-shaped third openings 1201, in the initial state, the third openings 1201 and the first openings 1101 are one-to-one corresponding in up and down, the cross-sectional area of the overlapping part is the largest, and the most drilling fluid can pass through; when only the second opening 1102 and any one of the third openings 1201 are in the up and down opposite position, the cross-sectional area of the overlapping part is the smallest, and the least drilling fluid can pass through, so that the flow rate of the drilling fluid flowing out of the bottom end of the fixed block 12 presents a certain regular and alternating change.

[0036] In an optional solution of the embodiment, the drill tool body comprises the upper joint 1 and the lower joint 14 coaxially arranged and threadedly connected, the outer upper portion of the upper joint 1 is provided with an outer conical thread gradually decreasing in diameter from bottom to top, which is used for screwing with the upper screw rod; the inner lower portion of the upper joint 1 is provided with an inner conical thread gradually decreasing in diameter from bottom to top, the outer upper portion of the lower joint 14 is provided with an outer conical thread gradually decreasing in diameter from bottom to top, the inner thread of the lower portion of the upper joint 1 is screwed with the outer thread of the upper portion of the lower joint 14; the inner lower portion of the lower joint 14 is provided with an inner conical thread gradually decreasing in diameter from bottom to top, which is used for screwing with the lower drill bit.

[0037] In an optional solution of the embodiment, the inner portion of the lower joint 14 is provided with the first step 15, the lower portion of the fixed block 12 abuts against the first step 15 and the fixed block 12 is fixedly connected to the lower joint 14.

[0038] In an optional solution of the embodiment, the power device comprises the fixed turbine 2 and the rotating turbine 6 rotationally connected to the lower portion of the fixed turbine 2, the upper portion of the fixed turbine 2 is connected to the inner wall of the upper portion of the upper joint 1, and the lower portion of the rotating turbine 6 is fixedly connected to the rotating block 11. The rotating turbine 6 is axially fixed by the fixed turbine 2, the rotating turbine 6 rotates and drives the rotating block 11 to rotate, and the fixed block 12 is fixedly connected to the lower joint 14, so that the cross-sectional area of the overlapping portion of the first flow channel and the second flow channel periodically and alternately changes.

[0039] For the shape and structure of the fixed turbine 2 and the connection mode of the fixed turbine 2 and the upper joint 1, please refer to Figure 1 and Figure 2 for specific description as follows:

[0040] The fixed turbine 2 comprises an inner body 201, a support ring 203 coaxially arranged with the inner body 201, support blocks 202 connecting the support ring 203 and the inner body 201, and fixed impeller blades 204 spirally distributed on the outer side of the inner body 201 from top to bottom; a gap is arranged between the support ring 203 and the inner body 201; the support ring 203 and the inner body 201 are connected through a plurality of circumferentially distributed support blocks 202; the fixed turbine 2 is of an integrated structure.

[0041] The inner portion of the upper joint 1 is provided with the second step 16 and the middle portion of the second step 16 is provided with a first recess, a circular ring-shaped retainer 3 is inserted into the first recess, the support ring 203 abuts against the second step 16, and the lower end of the support ring 203 abuts against the retainer 3. The support ring 203 is clamped and fixed on the second step 16 through the retainer 3, so as to avoid axial movement of the fixed turbine 2.

[0042] For the shape and structure of the rotating turbine 6 and the connection mode of the fixed turbine 2 and the rotating turbine 6, please refer to Figure 1 for specific description as follows:

[0043] The rotating turbine 6 is provided with an upper body 604, the outer diameter of the upper end of the upper body 604 is equal to the length of the outer diameter of the inner body 201, and the outer diameter of the upper body 604 gradually increases from the middle part to the bottom part; a plurality of rotating impeller blades 601 are helically distributed on the outer side of the upper end of the upper body 604 from top to bottom, and the rotating direction of the rotating impeller blades 601 is opposite to that of the fixed impeller blades 204, so that the drilling fluid flowing from top to bottom after passing through the fixed impeller blades 204 will impact the rotating impeller blades 601 relatively vertically, which can increase the force received by the rotating impeller blades 601 and drive the rotating turbine 6 to rotate axially.

[0044] In an optional scheme of the embodiment, the lower part of the inner body 201 of the fixed turbine 2 is provided with a small boss, the upper end of the upper body 604 of the rotating turbine 6 is provided with a corresponding small boss placing groove, and a second outer bearing sleeve 5 is fixedly installed on the inner wall of the small boss placing groove. Correspondingly, a second inner bearing sleeve 4 is fixedly installed on the outer wall of the small boss of the fixed turbine 2, the second inner bearing sleeve 4 and the second outer bearing sleeve 5 are coaxially installed and form a contact type bearing, so that the rotating turbine 6 is rotationally connected with the fixed turbine 2.

[0045] In an optional scheme of the embodiment, the rotating turbine 6 further includes a lower body 605 arranged below the upper body 604; an inner hole 603 extending upward to the bottom of the upper body 604 is arranged in the lower body 605, a plurality of radial through holes 602 are uniformly distributed on the upper part of the lower body 605, and the through holes 602 are communicated with the inner hole 603; the outer diameter of the top surface of the lower body 605 is equal to the length of the outer diameter of the bottom surface of the upper body 604, and the outer diameter of the lower body 605 gradually increases from top to bottom at the section where the through holes 602 are arranged. The outer diameter of the upper body 604 gradually increases from the middle part to the bottom of the through holes 602, that is, the diameter of the outer wall of the rotating turbine 6 between the rotating impeller blades 601 and the through holes 602 gradually increases from top to bottom, which is beneficial to introducing the fluid in the annular cavity between the upper joint 1 and the rotating turbine 6 into the through holes 602 and then into the inner hole 603.

[0046] For the connection mode of the rotating turbine 6 and the rotating block 11 and the connection mode of the rotating turbine 6 and the lower joint 14, please refer to Figure 1 , and the specific description is as follows:

[0047] In an alternative of the embodiment, the lower inner wall of the lower body 605 is provided with a third step 17, the rotating block 11 is provided in interference fit with the third step 17, and the lower end surface of the rotating block 11 is arranged in abutment with the upper end surface of the fixed block 12, so that the rotating block 11 can rotate under the driving of the rotating turbine 6, and the fixed block 12 is fixedly connected to the inner wall of the lower joint 14, and thus the cross-sectional area of the overlapping part between the first flow channel and the second flow channel periodically and alternately changes with the rotation of the rotating block 11.

[0048] In an alternative of the embodiment, the lower outer wall of the lower body 605 is rotatably connected with the upper joint 1 through a limiting connecting piece, the lower inner wall of the upper joint 1 is provided with a fourth step 18, the outer wall of the lower part of the rotating turbine 6 is provided with a fifth step 19; the limiting connecting piece comprises a limiting ring 9 abutting against the fourth step 18, a gasket 10 arranged below the limiting ring 9, a first outer bearing sleeve 8 mounted on the inner wall of the limiting ring 9, and a first inner bearing sleeve 7 mounted on the outer wall of the fifth step 19, the first inner bearing sleeve 7 and the first outer bearing sleeve 8 are coaxially mounted and form a contact type bearing, so that the lower body 605 of the rotating turbine 6 can be rotatably connected with the limiting ring 9; the upper end surface of the lower joint 14 abuts against the lower end surface of the gasket 10 to fix the limiting ring 9 and the gasket 10 on the fourth step 18. The limiting connecting piece serves to support the rotating turbine 6 to ensure the structural stability of the power device, and at the same time, the limiting connecting piece blocks the gap between the rotating turbine 6 and the inner wall of the upper joint 1, so that the fluid in the annular cavity between the rotating turbine 6 and the upper joint 1 can only flow into the inner hole 603 through the through hole 602.

[0049] In an alternative of the embodiment, the inner wall of the lower joint 14 is provided with a sixth step 20 located below the first step 15; the lower part of the fixed block 12 is provided with a flow guide block 13 abutting against the sixth step 20; the flow guide block 13 is provided with an inner cavity penetrating through the upper and lower parts, the upper part of the inner cavity is a variable-diameter hole with a diameter gradually decreasing from top to bottom, the lower part of the inner cavity is a small overflow hole with a fixed diameter, and the inner cavity is communicated with the inner hole 603 through the overlapping part of the first flow channel and the second flow channel. The flow guide block 13 serves to accelerate the fluid flowing from the inner hole 603, improve the impact force on the rock, and thus improve the rock breaking effect.

[0050] The working process of the rotating valve type near-bit efficiency-enhancing rock breaking drill is described as follows:

[0051] In the normal drilling process, the drilling tool of the present application is installed above the drill bit, and during drilling, the drilling fluid enters the annular cavity between the fixed turbine 2 and the upper joint 1 through the upper joint 1, and after flowing through the fixed impeller blades 204, the flow direction of the drilling fluid changes from vertical downward to axial downward at a certain angle, and the drilling fluid flowing out of the fixed impeller blades 204 impacts the rotating impeller blades 601 relatively vertically, thereby driving the rotating turbine 6 to rotate. The drilling fluid flows from top to bottom in the annular cavity between the fixed turbine 2 and the upper joint 1, and then enters the inner hole 603 through the through hole 602, and the drilling fluid continues to flow through the rotating block 11, which needs to pass through the two first openings 1101 and one second opening 1102 connected in the circumferential direction on the rotating block 11. At this time, due to the rotation of the rotating turbine 6, the rotating block 11 rotates along the axial direction, and due to the abutting arrangement of the adjacent end faces of the rotating block 11 and the fixed block 12, the cross-sectional area of the flow passage between the rotating block 11 and the fixed block 12 (i.e. the cross-sectional area of the overlapping portion) periodically alternates. In the initial state, the third opening 1201 and the first opening 1101 correspond one by one from top to bottom, and the cross-sectional area of the overlapping portion is the largest, and the drilling fluid that can pass through is the most, and when only the second opening 1102 and any one of the third openings 1201 are in the upper and lower relative positions, the cross-sectional area of the overlapping portion is the smallest, and the drilling fluid that can pass through is the least. Therefore, the drilling fluid flowing out of the bottom end of the fixed block 12 presents a certain regular alternating change in flow rate, and flows downward through the inner cavity of the flow guide block 13 and the lower joint 14 and enters the drill bit. The drilling fluid flowing out of the drill bit nozzle has obvious alternating changes in flow rate, which produces a pulsed jet flow, forms a pressure fluctuation on the surface of the rock, and causes the rock to be damaged under the action of instantaneous tensile stress and fatigue damage under the action of alternating stress; at the same time, during the process of the drilling fluid flowing out of the drill bit instantaneously decreasing in flow rate, a transient negative pressure is formed on the surface of the bottom hole rock, and the cuttings formed by the drill bit are sucked away from the bottom hole, avoiding repeated cutting of the cuttings at the bottom hole, significantly improving the rate of penetration, and ensuring the safety of drilling operations. The drilling tool of the present application has a simple structure and is directly installed between the screw and the drill bit, without affecting the inclination measurement effect of the directional instrument.

[0052] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A rotary valve type near-bit enhanced rock-breaking drilling tool, characterized in that: It includes a drill bit body, a rotating block (11) disposed within the drill bit body, a fixed block (12), and a power device for driving the rotating block (11) to rotate; The upper end face of the fixed block (12) is attached to the lower end face of the rotating block (11). The rotating block (11) is provided with a first flow channel that runs vertically through the top and bottom, and the fixed block (12) is provided with a second flow channel that runs vertically through the bottom and bottom. During the rotation of the rotating block (11), the first flow channel and the second flow channel always have an overlapping portion and the cross-sectional area of ​​the overlapping portion changes periodically. The first flow channel includes two symmetrically arranged arc-shaped first openings (1101) and an arc-shaped second opening (1102) connecting the two first openings (1101). The area of ​​the second opening (1102) is smaller than the area of ​​the first opening (1101), and both the first opening (1101) and the second opening (1102) are coaxially arranged with the power device. The second flow channel includes two symmetrically arranged arc-shaped third openings (1201). In the initial state, the third openings (1201) and the first openings (1101) correspond one-to-one. The drill body includes an upper connector (1) and a lower connector (14) that are coaxially arranged and threaded together. The upper outer part of the upper connector (1) is provided with an external thread, and the lower inner part of the lower connector (14) is provided with an internal thread. The lower connector (14) has a first step (15) on its inner side, and the lower part of the fixing block (12) abuts against the first step (15). The power unit includes a fixed turbine (2) and a rotating turbine (6) rotatably connected to the lower part of the fixed turbine (2). The upper part of the fixed turbine (2) is connected to the upper inner wall of the upper connector (1), and the lower part of the rotating turbine (6) is fixedly connected to the rotating block (11). The fixed turbine (2) includes an inner body (201), a support ring (203) coaxially arranged with the inner body (201), a support block (202) connecting the support ring (203) and the inner body (201), and fixed impeller blades (204) spirally distributed from top to bottom on the outside of the inner body (201). A gap is provided between the supporting ring (203) and the inner body (201); The upper connector (1) has a second step (16) on its inner side and a first groove in the middle of the second step (16). A circular retaining ring (3) is inserted into the first groove. The supporting ring (203) abuts against the second step (16) and the lower end of the supporting ring (203) abuts against the retaining ring (3).

2. The rotary valve type near-bit enhanced rock-breaking drilling tool according to claim 1, characterized in that, The rotating turbine (6) is provided with an upper body (604). The outer diameter of the upper part of the upper body (604) and the outer diameter of the inner body (201) are equal in length. Multiple rotating impeller blades (601) are spirally distributed from top to bottom on the outer side of the upper part of the upper body (604), and the rotating impeller blades (601) rotate in the opposite direction to the fixed impeller blades (204). The outer diameter of the upper body (604) gradually increases from the middle to the bottom.

3. The rotary valve type near-bit enhanced rock-breaking drilling tool according to claim 2, characterized in that, The rotary turbine (6) also includes a lower body (605) disposed below the upper body (604). The lower body (605) is provided with an inner hole (603) that runs vertically through it and the inner hole (603) extends upward to the bottom of the upper body (604). The upper part of the lower body (605) is provided with a plurality of radial through holes (602) evenly distributed in the circumference, and the through holes (602) communicate with the inner hole (603). The outer diameter of the top surface of the lower body (605) is equal to the outer diameter of the bottom surface of the upper body (604), and the outer diameter of the section of the lower body (605) with the through hole (602) gradually increases from top to bottom.

4. The rotary valve type near-bit enhanced rock-breaking drilling tool according to claim 3, characterized in that, The lower inner wall of the lower body (605) is provided with a third step (17), and the rotating block (11) and the third step (17) are configured to be interference fit; The lower outer wall of the lower body (605) is rotatably connected to the upper connector (1) through a limiting connector.

5. The rotary valve type near-bit enhanced rock-breaking drilling tool according to claim 4, characterized in that, A fourth step (18) is provided on the lower inner wall of the upper connector (1), and a fifth step (19) is provided on the lower outer wall of the rotating turbine (6). The limiting connector includes a limiting ring (9) abutting against the fourth step (18), a washer (10) disposed below the limiting ring (9), a first outer bearing sleeve (8) installed on the inner wall of the limiting ring (9), and a first inner bearing sleeve (7) installed on the outer wall of the fifth step (19). The upper end face of the lower connector (14) abuts against the lower end face of the washer (10) so that the limiting ring (9) and the washer (10) are fixed on the fourth step (18).

6. The rotary valve type near-bit enhanced rock breaking drilling tool according to claim 5, characterized in that, The inner wall of the lower connector (14) is provided with a sixth step (20) and the sixth step (20) is located below the first step (15); The lower part of the fixed block (12) is provided with a guide block (13) and the guide block (13) abuts against the sixth step (20). The guide block (13) is provided with an inner cavity that runs vertically through the interior. The upper part of the inner cavity is a variable diameter hole with a diameter that gradually decreases from top to bottom. The lower part of the inner cavity is a small flow hole with a fixed diameter. The inner cavity is connected to the inner hole (603) through the overlapping part of the first flow channel and the second flow channel.

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