Multi-anti-clamping PDC (polycrystalline diamond compact) drill bit

Abstract

The invention provides a multi-clamping-prevention PDC drill bit. The multi-clamping-prevention PDC drill bit comprises a drill bit body, a plurality of blades are arranged on the drill bit body at intervals, chip grooves are formed between the adjacent blades, stop block clamping prevention units are arranged in the chip grooves, fishtail-shaped clamping prevention units are arranged at the roots of the blades, and composite sheets and conical sharp teeth are arranged on the fishtail-shaped clamping prevention units. By means of the fishtail-shaped anti-clamping unit, fixed large falling blocks, key grooves and borehole steps can be subjected to back-scratching finishing, cutting and even crushing during lifting and back-scratching; the conical sharp teeth can be used for carrying out stress concentration crushing on falling blocks which are easy to move, so that the sizes of the falling blocks are reduced; by means of the stop block anti-blocking unit, large falling blocks falling from an upper well hole can be subjected to stress concentration crushing, the large falling blocks are prevented from falling into the well bottom and blocking a drill, existing falling blocks can be subjected to stress concentration crushing, the size of the falling blocks is reduced, and the falling blocks can be conveniently returned out in time. According to the invention, the occurrence probability of drill jamming can be reduced, the back-scratching jam releasing capability is improved, and the drilling period and cost are reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of oil extraction, and more specifically, to a multi-anti-sticking PDC drill bit. Background Art

[0002] Drilling engineering is an important part of the oil and gas extraction process. With the development of drilling technology, there are more and more deep wells and ultra-deep wells, especially three-dimensional long horizontal wells, which have small curvature change, large dogleg, high inclination rate, and some wells have horizontal sections exceeding 2500m. In addition, the reservoir encountered is relatively thin. The well inclination needs to be adjusted at any time during the drilling process, which can easily lead to irregular wellbore and greatly increase the probability of drill stuck accidents. At the same time, some wells also have complex working conditions such as collapse and shrinkage of the upper well section, many and large blocks falling, which can easily cause buried well drill stuck accidents. Once a drill stuck accident occurs, the handling process is slow and complicated, and it takes a long time. Sometimes it is necessary to fill the well and drill sideways, which greatly affects the drilling efficiency, and significantly increases the drilling cycle and cost, seriously affecting the drilling benefits.

[0003] When a drill bit is stuck, strong backscratching and reducing the accumulation of debris and rock debris on the upper slope of the drill bit can effectively reduce the risk of drill bit sticking. At present, conventional anti-stuck PDC drill bits usually install multiple backscratching holes at the 60° slope of the drill bit. By increasing the number of backscratching holes, the cutting area is increased, thereby improving the anti-stuck capability. However, due to the single backscratching and unstuck device, it is often still unable to effectively unstuck when encountering complex working conditions. Therefore, there is an urgent need for an anti-stuck PDC drill bit with multiple anti-stuck design units. Summary of the invention

[0004] To achieve the above-mentioned purpose, the technical solution adopted in the present application is: to provide a multiple anti-stuck PDC drill bit, including a drill bit body, a plurality of blades are arranged at intervals on the drill bit body, a chip groove is formed between adjacent blades, a block anti-stuck unit is arranged in the chip groove, a fishtail anti-stuck unit is arranged at the root of the blade, and a composite sheet and conical teeth are arranged on the fishtail anti-stuck unit.

[0005] Optionally, the crown line of the fishtail shaped anti-stuck unit is composed of tangent arc segments and oblique line segments, and the arc segments and the oblique line segments are arranged in sequence in the direction away from the blade, the arc angle of the arc segment is not less than 30°, and the angle between the oblique line segment and the center line of the drill bit is not greater than 30°.

[0006] Optionally, the composite sheet and the conical teeth on the fishtail-shaped anti-stuck unit are arranged in two rows along the thickness direction of the fishtail-shaped anti-stuck unit, wherein the composite sheet is arranged in the front row and the conical teeth are arranged in the back row.

[0007] Optionally, the block anti-stuck unit is a trapezoidal table structure, the larger side of the trapezoidal table structure is fixedly connected to the drill bit body, and its two end faces located in the axial direction of the drill bit form an angle of 45° with the radial direction of the drill bit, and both end faces are provided with conical teeth.

[0008] Optionally, the blade includes a cutting section and a gauge section, the cutting section is provided with front and rear rows of cutting teeth, wherein the cutting teeth in the front row are composite pieces, and the cutting teeth in the rear row are a structure of alternating composite pieces and conical teeth.

[0009] Optionally, a front row of the active diameter-keeping portion of the diameter-keeping section is provided with a composite sheet having a backward inclination angle, and a rear row is provided with a shock-absorbing joint.

[0010] Optionally, the gauge-keeping section comprises a gauge-keeping structure, an outer gauge-keeping surface of the gauge-keeping structure is provided with carbide teeth, and a side surface of the gauge-keeping structure is provided with active gauge-keeping teeth.

[0011] Optionally, the front end of the cutting segment is recessed toward the inner side of the drill body to form an inner cone, and the crown contour line of the cutting segment is a double arc structure.

[0012] Optionally, the number of the blade wings is 5, including 3 long blade wings and 2 short blade wings, and the long blade wings and the short blade wings are distributed alternately, and the 3 long blade wings are connected at the center of the drill bit to divide the chip groove into 3 independent spaces.

[0013] Optionally, 7 nozzles are arranged in each chip removal groove, wherein 2 nozzles are arranged in the core, and 5 nozzles are arranged outside, and the diameter of the nozzles arranged outside is larger than the diameter of the nozzles arranged in the core.

[0014] The beneficial effects of the multiple anti-stuck PDC drill bit provided by the present application are as follows: compared with the prior art, the present application arranges a composite sheet on the fishtail-shaped anti-stuck unit at the root of the blade, and when lifting and back-scratching, fixed large dropped blocks, key slots, and wellbore steps can be back-scratched, trimmed, cut, and even crushed; for some dropped blocks of moderate size, they are easy to move during back-scratching and cutting, making them difficult to be cut and destroyed, and the conical teeth arranged in the rear row can perform stress concentration crushing when the dropped blocks move (roll, move), thereby reducing the size of the dropped blocks; a block anti-stuck unit is arranged in the middle position of the chip groove, and conical teeth are arranged on the upper and lower inclined surfaces of the block, and the conical teeth on the upper end inclined surface can perform stress concentration crushing on larger dropped blocks falling from the upper wellbore, which can effectively prevent larger dropped blocks from falling into the bottom of the well, and prevent dropped blocks from being stuck between the blades and causing drill jamming; the conical teeth arranged on the lower end inclined surface can perform stress concentration crushing on existing dropped blocks, reduce the size of dropped blocks, and facilitate the timely return of dropped blocks. The present application can effectively suppress the probability of occurrence of pipe sticking and improve the ability of reverse drilling to resolve the sticking, thereby saving drilling cycle and cost and improving drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A three-dimensional diagram of a multi-anti-stick PDC drill bit provided in an embodiment of the present application;

[0017] Figure 2 A front view of a multi-anti-stick PDC drill bit provided in an embodiment of the present application;

[0018] Figure 3 A top view of a multi-anti-stick PDC drill bit provided in an embodiment of the present application;

[0019] Figure 4 A schematic diagram of the shape of a multi-anti-stick PDC drill bit provided in an embodiment of the present application;

[0020] Figure 5 A simplified diagram of the profile curve of a multi-anti-sticking PDC drill bit provided in an embodiment of the present application;

[0021] Among them, the reference numerals in the figure are:

[0022] 1. Drill body; 2. Blade; 3. Block anti-jamming unit; 4. Cone-shaped teeth; 5. Fishtail anti-jamming unit; 6. Chip removal groove; 7. Composite piece; 8. Shackle groove; 9. Connecting thread; 10. Gauge protection structure; 11. Carbide teeth; 12. Shock-absorbing joint; 13. Active gauge protection teeth; 14. Nozzle; 51. Arc segment; 52. Oblique line segment. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0025] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0027] Please also read Figure 1-Figure 5 , the multi-anti-stuck PDC drill bit provided in the embodiment of the present application is now described. For ease of understanding, in the present application, the end of the multi-anti-stuck PDC drill bit close to the wellhead when it is lowered into the wellbore for operation is defined as the upper end, the upstream end or similar terms, and the end away from the wellhead is defined as the lower end, the downstream end or similar terms. At the same time, the length direction along the multi-anti-stuck PDC drill bit is called the longitudinal direction, the axial direction or similar terms, and the direction perpendicular thereto is called the transverse direction, the radial direction or similar terms.

[0028] A multi-anti-stick PDC drill bit, see Figure 1 and Figure 2 , including a drill body 1, a plurality of blades 2 are arranged at intervals on the drill body 1, a chip groove 6 is formed between adjacent blades 2, a block anti-stuck unit 3 is arranged in the chip groove 6, a fishtail anti-stuck unit 5 is arranged at the root of the blade wing 2, and a composite piece 7 and a conical tooth 4 are arranged on the fishtail anti-stuck unit 5.

[0029] The present application sets a composite sheet 7 on the fishtail-shaped anti-stuck unit 5 at the root of the blade wing 2, and when lifting and scratching, fixed large fallen blocks, key slots, and wellbore steps can be scratched, trimmed, cut, or even crushed; for some moderate-sized fallen blocks, they are easy to move during the scratching and cutting, making them difficult to be cut and destroyed. The cone-pointed teeth 4 arranged in the rear row can perform stress concentration crushing when the fallen blocks move (roll, move), thereby reducing the size of the fallen blocks; a block anti-stuck unit 3 is arranged in the middle position of the chip groove 6, and cone-pointed teeth 4 are arranged on the upper and lower inclined surfaces of the block, and the cone-pointed teeth 4 on the upper end inclined surface can perform stress concentration crushing on larger fallen blocks falling from the upper wellbore, which can effectively prevent larger fallen blocks from falling into the bottom of the well, and prevent fallen blocks from being stuck between the blade wings 2 and causing drill jamming; the cone-pointed teeth 4 arranged on the lower end inclined surface can perform stress concentration crushing on existing fallen blocks, reduce the size of the fallen blocks, and facilitate the timely return of the fallen blocks. The present application can effectively suppress the probability of occurrence of pipe sticking and improve the ability of reverse drilling to resolve the sticking, thereby saving drilling cycle and cost and improving drilling efficiency.

[0030] The present application adopts a fishtail-shaped anti-stuck unit 5 arranged at the lower end of the blade wing 2 and a block anti-stuck unit 3 arranged in the middle of the chip groove 6. The design structures and working principles of the two anti-stuck units are different, but they can interact with each other to effectively prevent drill jamming accidents caused by various complex working conditions.

[0031] See also Figure 4 and Figure 5 In some embodiments of the present application, the crown line of the fishtail anti-stuck unit 5 is composed of a tangent arc segment 51 and an oblique line segment 52, and the arc segment 51 and the oblique line segment 52 are arranged in sequence along the direction away from the blade 2, the arc angle of the arc segment 51 is not less than 30°, and the angle between the oblique line segment 52 and the center line of the drill bit is not greater than 30°, and the upper end thereof is directly connected to the shank of the drill bit.

[0032] Compared with the traditional PDC drill bit, the crown surface formed by rotating the two tangent lines composed of the arc segment 51 and the oblique line segment 52 around the center line of the drill bit can reduce the accumulation of rock chips or falling pieces on the upper inclined surface of the gauge section, and at the same time can provide sufficient space to enhance the back-scratching cutting function. It can also increase the space for rock chips to pass through, and has a certain guiding effect on the rock chips sliding into the chip discharge groove 6.

[0033] In some embodiments of the present application, see Figure 4 The composite sheet 7 and the cone-shaped teeth 4 on the fishtail-shaped anti-stuck unit 5 are arranged in two rows along the thickness direction of the fishtail-shaped anti-stuck unit 5, wherein the composite sheet 7 is arranged in the front row and the cone-shaped teeth 4 are arranged in the back row.

[0034] By arranging a composite sheet 7 in the front row of the fishtail-shaped anti-stuck unit 5, fixed large fallen blocks, key slots, and wellbore steps can be scratched, trimmed, cut, and even crushed when lifting and scratching; for some fallen blocks of moderate size, they are easy to move during the scratching and cutting, making them difficult to be cut and destroyed. The conical teeth 4 arranged in the back row can perform stress concentration crushing when the fallen blocks move (roll, move), thereby reducing the size of the fallen blocks.

[0035] In some embodiments of the present application, see Figure 4 On the fishtail-shaped anti-stuck unit 5, the number of composite sheets 7 is 2, and the number of conical teeth 4 is 1. In other embodiments of the present application, the number of composite sheets 7 and conical teeth 4 on the fishtail-shaped anti-stuck unit 5 can also be set according to actual needs, and this application does not limit it.

[0036] See also Figure 2 and Figure 4 In some embodiments of the present application, the block anti-stuck unit 3 is a trapezoidal structure, and the larger side of the trapezoidal structure is fixedly connected to the drill body 1, and the two end faces located in the axial direction of the drill bit have an angle of 45° with the radial direction of the drill bit, and conical teeth 4 are provided on both end faces.

[0037] Specifically, the block anti-stuck unit 3 is located in the middle of each chip groove 6, and is composed of 6 surfaces, including an upper end inclined surface, a middle vertical surface, a lower end inclined surface, a left inclined surface, a right inclined surface, and a chip groove 6 surface, and is connected to the chip groove 6 in an integrated manner. The upper end inclined surface and the lower end inclined surface are both at an angle of 45° to the radial direction of the drill bit, and a cone-pointed tooth 4 is inlaid on each of the upper and lower inclined surfaces. The cone-pointed teeth 4 on the upper end inclined surface can perform stress concentration crushing on larger dropped blocks falling from the upper wellbore, which can effectively prevent larger dropped blocks from falling into the bottom of the well, and the dropped blocks from being stuck between the blades 2 to cause drill jamming; the cone-pointed teeth 4 on the lower end inclined surface can perform stress concentration crushing on existing dropped blocks, reduce the size of the dropped blocks, and facilitate the timely return of the dropped blocks with the drilling fluid.

[0038] In some embodiments of the present application, see Figure 2 The blade 2 includes a cutting section and a gauge section. The cutting section is provided with two rows of cutting teeth, front and rear. The cutting teeth in the front row are composite pieces 7, and the cutting teeth in the rear row are a structure in which composite pieces 7 and conical teeth 4 are alternately mixed.

[0039] In some embodiments of the present application, the front row of the cutting section adopts a circular composite piece 7 of specification 1613, and the drilling efficiency is improved by a reasonable tooth density. The second row of the cutting section adopts an alternating mixed structure of conical teeth 4 and circular composite pieces 7, which can effectively protect the front row composite pieces 7, avoid premature failure, assist in rock breaking, extend the service life of the drill bit and improve the footage capability.

[0040] In some embodiments of the present application, see Figure 3 and Figure 4 The front row of the active diameter protection part of the diameter protection section is provided with a composite piece 7, the composite piece 7 adopts a larger rearward inclination angle design, and the rear row is provided with a shock absorbing joint 12.

[0041] Specifically, the front row of the active gauge protection part adopts a circular composite piece 7 of specification 1313, and the second row adopts two shock-absorbing joints 12, thereby limiting the instantaneous cutting depth of the cutting teeth at the active gauge protection part at the bottom of the well in the horizontal direction, reducing the horizontal cutting load when the horizontal vibration occurs, reducing the early collapse of the composite piece 7 caused by the horizontal impact, and extending the service life of the drill bit. The composite piece 7 adopts a large back rake angle design to improve the impact resistance.

[0042] In some embodiments of the present application, see Figure 4 The diameter-guarding section includes a diameter-guarding structure 10 , an outer diameter-guarding surface of the diameter-guarding structure 10 is provided with carbide teeth 11 , and a side surface of the diameter-guarding structure 10 is provided with active diameter-guarding teeth 13 .

[0043] The use of hard alloy teeth 11 and active gauge teeth 13 with high wear resistance, strong impact resistance and good thermal stability can increase the service life of the drill bit during drilling, improve the working stability at the bottom of the well, enhance the gauge wear resistance and its ability to maintain the well wall quality.

[0044] See also Figure 2 and Figure 3 The front end of the cutting section of the blade 2 is recessed toward the inside of the drill bit body 1 to form an inner cone, and the crown contour of the cutting section is a double arc structure. Through this solution, the crown of the multi-anti-stuck PDC drill bit provided by the present application adopts a shallow inner cone and a double arc crown contour design, which can have high aggressiveness in directional wells or horizontal wells with small curvature radius and large dogleg degree, and can timely adjust the well inclination and azimuth, thereby improving the stability of the tool face during directional drilling.

[0045] See also Figure 3 In some embodiments of the present application, the number of blades 2 is 5, including 3 long blades and 2 short blades, and the long blades and the short blades are alternately distributed, and the 3 long blades are connected at the center of the drill bit, dividing the chip groove 6 into 3 independent spaces. With this solution, the cuttings will not interfere with each other when they are returned, and at the same time, the narrow area of ​​the flow channel between the long blades and the short blades is reduced, which is conducive to the timely return of the cuttings and the cleaning effect.

[0046] In other embodiments of the present application, the number of blades 2 can also be set according to actual needs, and the present application does not limit it.

[0047] In some embodiments of the present application, seven nozzles 14 are arranged in each chip groove 6, wherein two nozzles 14 are arranged in the core, and five nozzles 14 are arranged outside, and the diameter of the nozzles 14 arranged outside is larger than the diameter of the nozzles 14 arranged in the core.

[0048] This application configures nozzle combinations and hydraulic optimization calculations, selects the optimal nozzle combination, and cooperates with targeted improved flow channel design to improve the drill bit's own cavity storage capacity and kinetic chip removal function for large pieces of flakes and blocks, and alleviates the inefficient drilling fluid circulation effect caused by the complexity of the bottom hole.

[0049] In other embodiments of the present application, the cutting teeth may also be axe-shaped teeth, triangular teeth or other special-shaped teeth with strong impact resistance, and a dense tooth design may be adopted to ensure that the fishtail-shaped anti-stuck unit 5 at the upper end of the diameter-protecting structure 10 of each blade wing 2 has at least 2-3 cutting teeth to achieve full coverage of the bottom well projection.

[0050] In some embodiments of the present application, see Figure 1 A shackle groove 8 is provided on the side of the drill body 1, which is convenient for fixing the drill bit after the shackle is inserted, so that the drill tool and the drill bit are tightly connected through the threaded thread.

[0051] In some embodiments of the present application, see Figure 1 A connecting thread 9 is provided at the bottom of the drill body 1. The connecting thread 9 is a tapered thread for threaded connection with a drilling tool.

[0052] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A multi-anti-stick PDC drill bit, characterized by: The drill body comprises a drill bit body, on which a plurality of blades are arranged at intervals, a chip groove is formed between adjacent blades, a block anti-stuck unit is arranged in the chip groove, a fishtail anti-stuck unit is arranged at the root of the blade, and a composite sheet and conical teeth are arranged on the fishtail anti-stuck unit.

2. The multi-anti-sticking PDC drill bit according to claim 1, characterized in that: The crown line of the fishtail anti-stuck unit is composed of tangent arc segments and oblique line segments, and the arc segments and the oblique line segments are arranged in sequence in the direction away from the blade. The arc angle of the arc segment is not less than 30°, and the angle between the oblique line segment and the center line of the drill bit is not greater than 30°.

3. The multi-anti-sticking PDC drill bit according to claim 1, characterized in that: The composite sheets and the cone-shaped teeth on the fishtail-shaped anti-stuck unit are arranged in two rows along the thickness direction of the fishtail-shaped anti-stuck unit, wherein the composite sheets are arranged in the front row and the cone-shaped teeth are arranged in the rear row.

4. The multi-anti-sticking PDC drill bit according to claim 1, characterized in that: The block anti-stuck unit is a trapezoidal table structure, the larger side of the trapezoidal table structure is fixedly connected to the drill body, and the angles between its two end faces located in the axial direction of the drill and the radial direction of the drill are both 45°, and conical teeth are provided on both end faces.

5. The multi-anti-sticking PDC drill bit according to claim 1, characterized in that: The blade wing comprises a cutting section and a gauge section, wherein the cutting section is provided with front and rear rows of cutting teeth, wherein the cutting teeth in the front row are composite pieces, and the cutting teeth in the rear row are a structure of alternating composite pieces and conical teeth.

6. The multi-anti-sticking PDC drill bit according to claim 5, characterized in that: The front row of the active diameter-keeping portion of the diameter-keeping section is provided with a composite sheet, the composite sheet has a backward inclination angle, and the rear row is provided with a shock-absorbing joint.

7. The multi-anti-sticking PDC drill bit according to claim 5, characterized in that: The gauge-keeping section comprises a gauge-keeping structure, an outer gauge-keeping surface of the gauge-keeping structure is provided with carbide teeth, and a side surface of the gauge-keeping structure is provided with active gauge-keeping teeth.

8. The multi-anti-sticking PDC drill bit according to claim 5, characterized in that: The front end of the cutting segment is recessed toward the inner side of the drill body to form an inner cone, and the crown contour line of the cutting segment is a double arc structure.

9. The multi-anti-sticking PDC drill bit according to claim 1, characterized in that: The number of blades is 5, including 3 long blades and 2 short blades, and the long blades and the short blades are distributed alternately. The 3 long blades are connected at the center of the drill bit, dividing the chip groove into 3 independent spaces.

10. The multi-anti-sticking PDC drill bit according to claim 1, characterized in that: Each chip removal groove is provided with 7 nozzles, wherein 2 nozzles are arranged at the core, and 5 nozzles are arranged at the outside, and the diameter of the nozzle arranged at the outside is larger than the diameter of the nozzle arranged at the core.

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