Drilling and expanding two-stage integrated drill bit

Abstract

The invention belongs to the technical field of drilling equipment, and particularly relates to a drilling and expanding two-stage integrated drill bit which comprises a drilling body and a connecting body which are coaxially and integrally arranged front and back. A plurality of first drilling units and second drilling units are arranged in the circumferential direction of the drilling body at intervals in a penetrating mode, chip grooves are formed between the first drilling units and the second drilling units, and the first drilling units and the second drilling units each comprise a pilot hole body and a reaming body which are integrally arranged front and back. The pilot hole body of the first drilling unit extends to the axis of the top of the drilling body; a plurality of pilot hole protruding nozzles and reaming hole protruding nozzles are arranged on the drilling body, a drill bit inner cavity is formed in the connecting body in an axial penetrating mode, and the pilot hole protruding nozzles and the reaming hole protruding nozzles are communicated with the drill bit inner cavity. According to the technical scheme, the pilot hole body and the reaming body are arranged into a whole, so that the independent channel space is formed between the pilot hole body and the reaming body, rock debris formed by drilling can smoothly and rapidly return to an annulus area from a sheetflood area, and the chip removal efficiency is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of drilling equipment, and particularly relates to a combined drilling and reaming two-stage integrated bit. Background Art

[0002] With the advancement of China's oil and gas exploration towards deep formations, the exploration business demand for deep and ultra-deep wells is increasing day by day. Accordingly, the designed wellbore size increases and the well section significantly lengthens. A series of problems such as poor rock-breaking efficiency of the bit in the large-size wellbore section, serious bit damage, low mechanical drilling rate, and short footage per trip are particularly prominent, severely restricting the drilling speed-up operation. Specifically, since the rock-breaking of a PDC bit is achieved by the scraping method of the composite inserts, as the bit outer diameter increases, the linear velocity of the outer row of teeth scraping against the formation rock will increase accordingly, resulting in a significant increase in the degree of wear and impact, short service life of the cutting teeth, and short footage per trip of the bit. On the other hand, after the bit size increases, its specific weight on bit and specific hydraulic power significantly decrease, resulting in a further reduction in its rock-breaking efficiency.

[0003] Currently, the industry has adopted a solution with a reamer while drilling, but this solution usually has a limited reaming amplitude, and there are problems such as uneven distribution of the weight on bit and large torque fluctuations, resulting in low drilling and reaming cooperation efficiency, serious damage to the reamer, and still unsatisfactory mechanical drilling rate and footage per trip. Therefore, improving the drilling speed of large-size wellbores still needs to be considered from the improvement of the bit itself.

[0004] In order to improve and solve the above problems, relevant bit manufacturers and researchers have done work such as increasing the tooth density, increasing the number of blades, and adjusting the inclination angle of the cutting teeth. However, due to the fact that the basic performance of the composite inserts has not changed essentially, and it is impossible to find a good balance between the attacking power and the anti-destructive ability, the expected results have not been achieved. How to develop a new type of bit to effectively improve the rock-breaking efficiency and mechanical drilling rate in the large-size well section and increase the footage per trip has become the key to speeding up the large-size well section and shortening the operation cycle. Summary of the Invention

[0005] The purpose of the present invention is to propose a combined drilling and reaming two-stage integrated bit aiming at the deficiencies of the above-mentioned existing technologies, which can improve the drilling efficiency of large-size wellbores, increase the mechanical drilling rate, and increase the footage per trip.

[0006] The present invention is realized by adopting the following technical solutions:

[0007] A drilling and reaming integrated bit, characterized in that it includes a drilling body and a connecting body that are coaxially and integrally arranged front and back; on the side of the drilling body, a number of first drilling units and second drilling units are arranged at intervals in the circumferential direction. A chip discharge groove is provided between the first drilling unit and the second drilling unit. Both the first drilling unit and the second drilling unit include a pilot body and a reaming body that are integrally arranged front and back. The pilot body of the first drilling unit extends to the axis at the top of the drilling body; a number of pilot raised nozzles and reaming raised nozzles are provided on the drilling body. An inner cavity of the bit is axially penetrated through the connecting body, and the inner cavity of the bit extends into the interior of the drilling body. The pilot raised nozzles and the reaming raised nozzles are respectively connected to the inner cavity of the bit.

[0008] Preferably, the pilot raised nozzles are arranged at the top of the drilling body; the reaming raised nozzles are arranged in the chip discharge groove between the first drilling unit and the second drilling unit and are at the same height at the position where the reaming body transitions to the pilot body.

[0009] Preferably, the first drilling unit and the second drilling unit are arranged obliquely in the same direction, so that there is a phase angle difference θ between the reaming body and the pilot body in the same drilling unit, and 10° ≤ θ ≤ 30°.

[0010] Preferably, the pilot body includes a pilot section blade and a pilot section gauge protection that are integrally arranged front and back. Pilot cutting tooth units are arranged on the pilot section blade.

[0011] Preferably, the pilot cutting tooth units include a number of rows of pilot cutting tooth groups arranged at intervals along the length direction of the pilot section blade; there is one pilot PDC tooth in each row of pilot cutting tooth groups on the pilot body structure extending to the top of the drilling body, and there are two pilot PDC teeth in each row of pilot cutting tooth groups on the pilot body structure on the side of the drilling body.

[0012] Preferably, the reaming body includes a reaming section blade and a reaming section gauge protection that are integrally arranged front and back. The reaming section blade is integrally arranged with the pilot section gauge protection, and reaming cutting tooth units are arranged on the reaming section blade.

[0013] Preferably, the reaming cutting tooth units include a number of rows of pilot cutting tooth groups arranged at intervals along the length direction of the reaming section blade, and there are two reaming PDC teeth in each row of reaming cutting tooth groups.

[0014] Preferably, the pilot body and the reaming body in the same drilling unit are arranged offset in the circumferential direction of the drilling body, so that the offset distance between the pilot cutting tooth units and the reaming cutting tooth units in the circumferential direction of the drilling body is N, and 10 mm ≤ N ≤ 50 mm.

[0015] Preferably, on the side of the drilling body, the radially highest points of the pilot bits in all the first drilling units and the second drilling units are on the same circle; let this circle be the circumcircle of the pilot bit, and the radially highest points of the reamer bits in all the first drilling units and the second drilling units are on the same circle; let this circle be the circumcircle of the reamer bit; the radius ratio of the circumcircle of the pilot bit to the circumcircle of the reamer bit is K, and 0.52 ≤ K ≤ 0.86.

[0016] Preferably, let the diameter of the circumcircle of the pilot bit be D, and the distance from the bottom of the cutter blade in the pilot section to the top of the reaming cutting tooth unit be L, then 0.4D ≤ L ≤ 1.5D.

[0017] Preferably, the diameters of the pilot raised nozzles and the reamer raised nozzles are d, and the raised height is h, then 4d ≤ h ≤ 6d.

[0018] The beneficial technical effects brought by the present invention:

[0019] 1) This technical solution provides a drill-reaming two-stage integrated bit, which is provided with two-stage structures of pilot reaming (i.e., the pilot section and the reamer section), supports the setting of a relatively small-sized pilot section and a relatively large-sized reamer section. The rock-breaking efficiency is higher than that of directly using a large-sized bit. Therefore, the formation rock can be quickly broken. As the rock is hollowed out, the original in-situ stress in the bottom-hole rock under the compaction effect is released, and its strength is reduced accordingly. Therefore, the cutting difficulty of the rear reamer section can be reduced, so as to achieve efficient rock breaking and improve the mechanical drilling rate. Further, although the linear velocity of the reamer section remains unchanged under the same conditions, due to the reduced rock-breaking difficulty of the reamer section, the wear and consumption of the cutting teeth are reduced. Therefore, the cutting stroke can be increased and the bit penetration can be improved.

[0020] 2) In this technical solution, compared with the prior art in which the pilot bit and the reamer bit are not integrally arranged and the cuttings formed during drilling mix and flow between each pilot bit and each reamer bit, reducing the chip removal efficiency, in this technical solution, the pilot bit and the reamer bit are arranged as a whole, forming a separate channel space between them. The cuttings formed during drilling can smoothly return to the annulus area quickly from the overflow area, effectively improving the chip removal efficiency.

[0021] 3) The pilot raised nozzles and the reamer raised nozzles adopt elongated nozzles, and the reamer raised nozzles are arranged at the same height at the transition position from the reamer bit in the chip removal groove to the pilot bit, which can effectively reduce the temperature of the composite chips and further improve the chip return efficiency.

[0022] 4) This technical solution improves the bit from three aspects: the pilot-reamer ratio, the stage spacing, and the misalignment angle between the cutter blades in the pilot section and the cutter blades in the reamer section, realizing the dynamic balance of the rock-breaking speeds of the pilot section and the reamer section, further achieving the purpose of overall speed increase, and effectively avoiding the mutual drag between the pilot section and the reamer section. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the overall structure of a combined drilling and reaming two-stage integrated bit;

[0024] Figure 2 It is a front view structural schematic diagram of a combined drilling and reaming two-stage integrated bit;

[0025] Figure 3 It is a top view structural schematic diagram of a combined drilling and reaming two-stage integrated bit.

[0026] In the figure:

[0027] 1. Drilling body; 2. Connecting body; 3. First drilling unit; 4. Second drilling unit; 5. Chip removal groove; 6. Pilot bit body; 6.1 Pilot bit section blade; 6.2 Pilot bit section gauge; 6.3 Pilot bit PDC teeth; 7. Reaming body; 7.1 Reaming section blade; 7.2 Reaming section gauge; 7.3 Reaming PDC teeth; 8. Pilot bit raised nozzle; 9. Reaming raised nozzle. Specific embodiments

[0028] To make the objectives, technical solutions and advantages of the invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention.

[0029] Therefore, the detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts fall within the scope of protection of the present invention.

[0030] Embodiment 1

[0031] This embodiment discloses a combined drilling and reaming two-stage integrated bit. As a basic implementation manner of this technical solution, as Figure 1A disclosed drilling and reaming two-stage integrated bit includes a drilling body 1 and a connecting body 2 which are coaxially and integrally arranged front and back. On the side surface of the drilling body 1, a number of first drilling units 3 and second drilling units 4 are arranged at intervals in the circumferential direction, and a chip discharge groove 5 is provided between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot hole body 6 and a reaming body 7 which are integrally arranged front and back. That is, in this technical solution, the two stages (the pilot hole body 6 and the reaming body 7) are in a non-disconnected state and are arranged as a prismatic integral structure. The pilot hole body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; a number of pilot hole protruding nozzles 8 and reaming protruding nozzles 9 are arranged on the drilling body 1, and a drill bit inner cavity (hidden in the figure) is axially penetrated inside the connecting body 2, and the drill bit inner cavity extends to the inside of the drilling body 1, and the pilot hole protruding nozzles 8 and the reaming protruding nozzles 9 are respectively connected to the drill bit inner cavity.

[0032] In a drilling and reaming two-stage integrated bit disclosed in this technical solution, a pilot and reaming two-stage structure is set. The front end is in the shape of a conventional drill bit, which is called the pilot hole section (that is, the overall structure formed by all the pilot hole bodies 6 and the drilling body 1 in the middle), and the rear end is in the shape of a reamer, which is called the reaming section (that is, the overall structure formed by all the reaming bodies 7 and the drilling body 1 in the middle). Based on this structure, a pilot hole section with a relatively small size can be set, and the rock breaking efficiency is higher than that of directly using a drill bit with a large size specification. Therefore, the formation rock can be quickly broken; further, a reaming section with a relatively large size can be set. As the rock is hollowed out, the original in-situ stress in the bottom-hole rock is released under the compaction effect, and its strength is reduced accordingly. Therefore, the cutting difficulty of the rear reaming section can be reduced, so as to achieve efficient rock breaking and improve the mechanical drilling speed. On the other hand, although the linear velocity of the reaming section does not change under the same conditions, due to the reduced rock breaking difficulty of the reaming section, the wear and consumption of the cutting teeth are reduced. Therefore, the cutting stroke can be increased and the drill bit footage can be improved.

[0033] In addition, if the pilot hole body 6 and the reaming body 7 are not integrally arranged, the cuttings formed during drilling will mix and flow between each pilot hole body 6 and each reaming body 7, reducing the chip discharge efficiency. In this regard, in this technical solution, the pilot hole body 6 and the reaming body 7 are set as a whole, so as to form a separate channel space between them. The cuttings formed during drilling can smoothly return from the overflow area to the annulus area quickly, effectively improving the chip discharge efficiency.

[0034] Embodiment 2

[0035] This embodiment discloses a drilling and reaming two-stage integrated bit. As a preferred implementation manner of this technical solution, as Figure 1As shown, a drilling and reaming integrated double-stage bit includes a drilling body 1 and a connecting body 2 which are coaxially and integrally arranged front and back. On the side of the drilling body 1, a number of first drilling units 3 and second drilling units 4 are arranged at intervals in the circumferential direction. Between the first drilling units 3 and the second drilling units 4 is a chip removal groove 5. Both the first drilling units 3 and the second drilling units 4 include a pilot hole body 6 and a reaming body 7 which are integrally arranged front and back. The pilot hole body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; on the drilling body 1, a number of pilot hole protruding nozzles 8 and reaming hole protruding nozzles 9 are arranged. Inside the connecting body 2, a drill bit inner cavity (hidden in the figure) is axially penetrated, and the drill bit inner cavity extends into the interior of the drilling body 1. The pilot hole protruding nozzles 8 and the reaming hole protruding nozzles 9 are respectively connected to the drill bit inner cavity.

[0036] Furthermore, the pilot hole protruding nozzles 8 are arranged at the top of the drilling body 1; the reaming hole protruding nozzles 9 are arranged in the chip removal groove 5 between the first drilling units 3 and the second drilling units 4 and are at the same height at the position where the reaming body 7 transitions to the pilot hole body 6.

[0037] Furthermore, if the diameter of the pilot hole protruding nozzles 8 and the reaming hole protruding nozzles 9 is d and the protruding height is h, then 4d ≤ h ≤ 6d. That is, the pilot hole protruding nozzles 8 and the reaming hole protruding nozzles 9 in this technical solution adopt extended nozzles. This extended nozzle protrudes a certain distance above the surface of the drilling body 1, and this distance is h, generally 4 - 6 times the diameter d of the extended nozzle. Preferably, h = 5d. Additionally, more specifically, at the top of the drilling body 1, three extended nozzles (pilot hole protruding nozzles 8) are arranged between two adjacent first drilling units 3, and the three extended nozzles are arranged in a triangular structure.

[0038] A drilling and reaming integrated double-stage bit disclosed in this technical solution is provided with a leading and reaming two-stage structure. The front end is in the shape of a conventional drill bit, called the pilot hole section (i.e., the overall structure formed by all the pilot hole bodies 6 and the drilling body 1 in the middle), and the rear end is in the shape of a reamer, called the reaming section (i.e., the overall structure formed by all the reaming bodies 7 and the drilling body 1 in the middle). Based on this structure, a relatively small-sized pilot hole section can be set, and the rock-breaking efficiency is higher than that of directly using a drill bit with a large-size specification. Therefore, the formation rock can be broken quickly; furthermore, a relatively large-sized reaming section can be set. As the rock is hollowed out, the original in-situ stress in the bottom-hole rock is released under the compaction effect, and its strength decreases accordingly. Therefore, the cutting difficulty of the rear reaming section can be reduced, thereby achieving efficient rock breaking and the purpose of increasing the mechanical drilling rate. On the other hand, although the linear velocity of the reaming section remains unchanged under the same conditions, due to the reduced rock-breaking difficulty of the reaming section, the wear and consumption of the cutting teeth are reduced. Therefore, the cutting stroke can be increased and the drill bit footage can be improved.

[0039] In addition, if the pilot hole body 6 and the reaming body 7 are not integrally arranged, the cuttings formed during drilling will mix and flow between each pilot hole body 6 and each reaming body 7, reducing the chip removal efficiency. In this regard, in this technical solution, the pilot hole body 6 and the reaming body 7 are set as a whole, so as to form a separate channel space between them. The cuttings formed during drilling can smoothly return from the overflow area to the annulus area quickly, effectively improving the chip removal efficiency. The pilot hole convex nozzle 8 and the reaming hole convex nozzle 9 adopt elongated nozzles, and the reaming hole convex nozzle 9 is arranged at the same height at the transition position from the reaming body 7 in the chip removal groove 5 to the pilot hole body 6, which can effectively reduce the temperature of the composite chip and further improve the chip return efficiency.

[0040] It can be understood from the above introduction of the working principle that the optimal application range of this technical solution is the large-size wellbore section, but it is not limited to this, and the conventional-size wellbore section is also applicable. It should be noted that for the drill bit used in the large-size wellbore section, this technical solution refers to the specifications with a drill bit diameter of 406.4 mm in the pilot hole section / 444.5 mm and above in the reaming hole section.

[0041] Embodiment 3

[0042] This embodiment discloses a drill and ream dual-stage integrated drill bit. As a preferred implementation manner of this technical solution, as Figure 1 shown in a drill and ream dual-stage integrated drill bit, which includes a drilling body 1 and a connecting body 2 that are coaxially and integrally arranged front and back. On the side surface of the drilling body 1, a plurality of first drilling units 3 and second drilling units 4 are arranged at intervals in the circumferential direction. The chip removal groove 5 is located between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot hole body 6 and a reaming body 7 that are integrally arranged front and back. The pilot hole body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; a plurality of pilot hole convex nozzles 8 and reaming hole convex nozzles 9 are arranged on the drilling body 1, and a drill bit inner cavity (hidden in the figure) is axially penetrated inside the connecting body 2, and the drill bit inner cavity extends to the inside of the drilling body 1. The pilot hole convex nozzles 8 and the reaming hole convex nozzles 9 are respectively connected to the drill bit inner cavity.

[0043] Based on the above structure, this technical solution improves the rock-breaking efficiency of the drill bit by means of drill and ream grading. In addition, the rock-breaking speeds of the pilot hole section and the reaming hole section need to reach a dynamic balance to achieve the purpose of overall speed increase. Otherwise, the pilot hole section and the reaming hole section will hold each other back. Based on this, related to the characteristics of this technical solution, there are three factors that determine the use effect of the drill bit, namely the pilot hole to reaming hole ratio, the stage spacing, and the misalignment angle between the cutter blades 6.1 in the pilot hole section and the cutter blades 7.1 in the reaming hole section.

[0044] As a preferred embodiment of the present technical solution, this embodiment is improved from the size and direction of the misalignment angle between the pilot bit blade 6.1 and the reamer bit blade 7.1. Specifically, the first drilling unit 3 and the second drilling unit 4 are arranged to be inclined in the same direction, so that there is a phase angle difference θ between the reamer body 7 and the pilot body 6 in the same drilling unit, and 10° ≤ θ ≤ 30°. That is, the bit blade of the present technical solution is designed with a certain angle difference between the front end and the rear end. As Figure 3 shown, from the top view, when the bit rotates clockwise at the bottom of the well, there is a certain misalignment between the cutting structure action area on the front-end part of the blade and the rear end, avoiding cutting the same row of rocks by the front and rear ends at the same time, causing the peak and valley values of the torque change to be superimposed, and reducing the damage of the stick-slip effect to the bit. This is particularly obvious for large-sized bits.

[0045] Embodiment 4

[0046] This embodiment discloses a drill-reamer integrated bit. As a preferred embodiment of the present technical solution, as Figure 1 shown, a drill-reamer integrated bit includes a drilling body 1 and a connecting body 2 that are coaxially arranged front and rear. On the side surface of the drilling body 1, a plurality of first drilling units 3 and second drilling units 4 are alternately arranged along the circumferential direction, and a chip removal groove 5 is provided between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot body 6 and a reamer body 7 that are integrally arranged front and rear. The pilot body 6 of the first drilling unit 3 extends to the center of the top of the drilling body 1; a plurality of pilot raised nozzles 8 and reamer raised nozzles 9 are provided on the drilling body 1, and a bit inner cavity (hidden in the figure) is axially penetrated inside the connecting body 2, and the bit inner cavity extends to the inside of the drilling body 1, and the pilot raised nozzles 8 and the reamer raised nozzles 9 are respectively connected to the bit inner cavity.

[0047] Furthermore, the pilot body 6 includes a pilot bit blade 6.1 and a pilot bit gauge 6.2 that are integrally arranged front and rear, and a pilot cutting tooth unit is arranged on the pilot bit blade 6.1; the reamer body 7 includes a reamer bit blade 7.1 and a reamer bit gauge 7.2 that are integrally arranged front and rear, the reamer bit blade 7.1 is integrally arranged with the pilot bit gauge 6.2, and a reamer cutting tooth unit is arranged on the reamer bit blade 7.1.

[0048] Based on the above structure, the present technical solution improves the rock-breaking efficiency of the bit by means of drill-reamer grading. In addition, it is necessary to achieve a dynamic balance between the rock-breaking speeds of the pilot section and the reamer section to achieve the overall speed-up purpose. Otherwise, the pilot section and the reamer section will drag each other down. Based on this, related to the features of the present technical solution, there are three factors that determine the use effect of the bit, namely, the pilot-reamer ratio, the stage spacing, and the misalignment angle between the pilot bit blade 6.1 and the reamer bit blade 7.1.

[0049] As a preferred embodiment of the present technical solution, this embodiment is improved in terms of the magnitude and direction of the misalignment angle between the pilot bit blade 6.1 and the reamer bit blade 7.1. Specifically, the pilot body 6 and the reamer body 7 in the same drilling unit are arranged with a circumferential misalignment along the drilling body 1, so that the misalignment distance between the pilot cutting tooth unit and the reamer cutting tooth unit along the circumference of the drilling body 1 is N, and 10 mm ≤ N ≤ 50 mm. That is, the bit blade of the present technical solution is designed with a certain angle difference between the front and rear ends. For example, Figure 3 As shown, from the top view, when the bit rotates clockwise at the bottom of the well, there is a certain misalignment between the action area of the pilot cutting tooth unit on the front-end part of the blade and the reamer cutting tooth unit at the rear end, avoiding cutting the same row of rocks at the front and rear ends at the same time, resulting in the superposition of the peak and valley values of the torque change, and reducing the damage of the stick-slip effect to the bit. This is particularly obvious for large-sized bits.

[0050] Embodiment 5

[0051] This embodiment discloses a drill-reamer integrated bit. As a preferred embodiment of the present technical solution, as shown in Figure 1 a drill-reamer integrated bit, which includes a drilling body 1 and a connecting body 2 that are coaxially and integrally arranged front and rear. On the side surface of the drilling body 1, a plurality of first drilling units 3 and second drilling units 4 are arranged at intervals along the circumference, and a chip discharge groove 5 is provided between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot body 6 and a reamer body 7 that are integrally arranged front and rear. The pilot body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; a plurality of pilot raised nozzles 8 and reamer raised nozzles 9 are provided on the drilling body 1. A bit inner cavity (hidden in the figure) is axially penetrated inside the connecting body 2, and the bit inner cavity extends to the inside of the drilling body 1. The pilot raised nozzles 8 and the reamer raised nozzles 9 are respectively connected to the bit inner cavity.

[0052] Furthermore, the pilot body 6 includes a pilot bit blade 6.1 and a pilot bit gauge 6.2 that are integrally arranged front and rear. The pilot bit blade 6.1 is provided with a pilot cutting tooth unit; the reamer body 7 includes a reamer bit blade 7.1 and a reamer bit gauge 7.2 that are integrally arranged front and rear. The reamer bit blade 7.1 is integrally arranged with the pilot bit gauge 6.2, and the reamer bit blade 7.1 is provided with a reamer cutting tooth unit.

[0053] Furthermore, the pilot cutting tooth unit includes two rows of pilot cutting tooth groups arranged side by side. Each row of pilot cutting tooth groups contains a number of pilot PDC teeth 6.3 spaced along the length direction of the pilot section blade 6.1. Among them, for the pilot cutting tooth unit in the first drilling unit 3, the number of pilot PDC teeth 6.3 in the first row of pilot cutting tooth groups (the row of pilot cutting tooth groups that first cuts the rock when the drill bit operates) is more than the number of pilot PDC teeth 6.3 in the second row of pilot cutting tooth groups (the row of pilot cutting tooth groups that later cuts the rock when the drill bit operates). The extra part of the pilot PDC teeth 6.3 extends and is arranged on the structure of the pilot section blade 6.1 at the top of the drilling body 1. Correspondingly, the reaming cutting tooth unit includes two rows of reaming cutting tooth groups arranged side by side. Each row of reaming cutting tooth groups contains a number of reaming PDC teeth 7.3 spaced along the length direction of the reaming section blade 7.1. Further, the number of reaming PDC teeth 7.3 in the two rows of reaming cutting tooth groups is the same.

[0054] Furthermore, the pilot body 6 and the reaming body 7 in the same drilling unit are arranged circumferentially offset along the circumference of the drilling body 1, so that the circumferential offset distance between the pilot cutting tooth unit and the reaming cutting tooth unit along the circumference of the drilling body 1 is N, and 10mm ≤ N ≤ 50mm, that is, the circumferential (circumference of the drilling body 1) distance between the second row of pilot cutting tooth groups and the first row of reaming cutting tooth groups (the row of reaming cutting tooth groups that first cuts the rock when the drill bit operates) is N.

[0055] Embodiment 6

[0056] This embodiment discloses a drilling and reaming dual-stage integrated drill bit. As a preferred implementation of the technical solution, as Figure 1 shown in a drilling and reaming dual-stage integrated drill bit, which includes a drilling body 1 and a connecting body 2 that are coaxially and integrally arranged front and back. On the side surface of the drilling body 1, a number of first drilling units 3 and second drilling units 4 are arranged at intervals along the circumference. The chip removal groove 5 is located between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot body 6 and a reaming body 7 that are integrally arranged front and back. The pilot body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; a number of pilot raised nozzles 8 and reaming raised nozzles 9 are arranged on the drilling body 1. A drill bit inner cavity (hidden in the figure) is axially penetrated inside the connecting body 2, and the drill bit inner cavity extends to the inside of the drilling body 1. The pilot raised nozzles 8 and the reaming raised nozzles 9 are respectively connected to the drill bit inner cavity.

[0057] Further, the pilot hole body 6 includes a pilot hole section blade 6.1 and a pilot hole section gauge 6.2 which are integrally arranged front and back. The pilot hole section blade 6.1 is provided with a pilot hole cutting tooth unit; the reaming body 7 includes a reaming section blade 7.1 and a reaming section gauge 7.2 which are integrally arranged front and back. The reaming section blade 7.1 is integrally arranged with the pilot hole section gauge 6.2, and the reaming section blade 7.1 is provided with a reaming cutting tooth unit.

[0058] Based on the above structure, the technical solution improves the rock-breaking efficiency of the drill bit by means of drilling and reaming in stages. In addition, it is necessary to achieve a dynamic balance between the rock-breaking speeds of the pilot hole section and the reaming section to achieve the purpose of overall speed increase. Otherwise, the pilot hole section and the reaming section will hold each other back. Based on this, related to the features of the technical solution, there are three factors that determine the use effect of the drill bit, namely, the pilot-ream ratio, the stage spacing, and the misalignment angle between the pilot hole section blade 6.1 and the reaming section blade 7.1.

[0059] As a preferred implementation mode of the technical solution, this embodiment improves the drill bit in terms of the pilot-ream ratio. The pilot-ream ratio refers to the ratio of the outer diameter of the pilot hole section of the drill bit to the outer diameter of the reaming section. Specifically, on the side of the drilling body 1, the radial highest points of all the pilot hole bodies 6 among the first drilling units 3 and the second drilling units 4 are on the same circle; let this circle be the pilot hole circumscribed circle, and the radial highest points of all the reaming bodies 7 among the first drilling units 3 and the second drilling units 4 are on the same circle; let this circle be the reaming circumscribed circle; the radius ratio of the pilot hole circumscribed circle to the reaming circumscribed circle is K, that is, the pilot-ream ratio of the drill bit of the technical solution is K, and 0.52 ≤ K ≤ 0.86. Based on this range, the pilot-ream ratio K can be specifically adjusted according to the drillability and destructibility of the target formation rock and the relationship between the formation pressure and the liquid column pressure in the wellbore. For example, when considering drilling in the sandy shale interbed section, K = 0.83. In this way, it is of great significance to make the mechanical drilling speed of the pilot hole section and the mechanical drilling speed of the reaming section reach a dynamic balance.

[0060] Embodiment 7

[0061] This embodiment discloses a drill-ream two-stage integrated drill bit. As a preferred implementation mode of the technical solution, as Figure 1As shown, a drilling and reaming integrated double-stage bit includes a drilling body 1 and a connecting body 2 which are coaxially and integrally arranged front and back. On the side surface of the drilling body 1, a number of first drilling units 3 and second drilling units 4 are alternately arranged at intervals along the circumferential direction, and a chip discharge groove 5 is provided between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot hole body 6 and a reaming body 7 which are integrally arranged front and back. The pilot hole body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; a number of pilot hole raised nozzles 8 and reaming raised nozzles 9 are provided on the drilling body 1, and a drill bit inner cavity (hidden in the figure) is axially penetrated inside the connecting body 2, and the drill bit inner cavity extends to the inside of the drilling body 1, and the pilot hole raised nozzles 8 and the reaming raised nozzles 9 are respectively connected to the drill bit inner cavity.

[0062] Furthermore, the pilot hole body 6 includes a pilot hole section blade 6.1 and a pilot hole section gauge 6.2 which are integrally arranged front and back. The pilot hole section blade 6.1 is provided with a pilot hole cutting tooth unit; the reaming body 7 includes a reaming section blade 7.1 and a reaming section gauge 7.2 which are integrally arranged front and back. The reaming section blade 7.1 is integrally arranged with the pilot hole section gauge 6.2, and the reaming section blade 7.1 is provided with a reaming cutting tooth unit.

[0063] Based on the above structure, the technical solution improves the rock-breaking efficiency of the drill bit by means of drilling and reaming grading. In addition, it is necessary to achieve a dynamic balance between the rock-breaking speeds of the pilot hole section and the reaming section to achieve the purpose of overall speed increase. Otherwise, the pilot hole section and the reaming section will drag each other down. Based on this, related to the characteristics of this technical solution, there are three factors that determine the use effect of the drill bit, namely the pilot-ream ratio, the stage spacing, and the misalignment angle between the pilot hole section blade 6.1 and the reaming section blade 7.1.

[0064] As a preferred implementation manner of this technical solution, this embodiment improves the drill bit in terms of the stage spacing. The stage spacing refers to the distance between the bottom surface of the pilot hole section and the first tooth of the reaming section in the axial direction. The value of the stage spacing L is related to the diameter of the pilot hole section. Specifically, the diameter of the circumscribed circle of the pilot hole is D, and the distance from the bottom of the pilot hole section blade 6.1 to the top of the reaming cutting tooth unit is L, then 0.4D ≤ L ≤ 1.5D.

[0065] Embodiment 8

[0066] This embodiment discloses a drilling and reaming dual-stage integrated drill bit. As a preferred implementation of this technical solution, it includes a drilling body 1 and a connecting body 2 that are coaxially and integrally arranged front and back; on the side of the drilling body 1, a number of first drilling units 3 and second drilling units 4 are arranged at intervals in the circumferential direction. A chip discharge groove 5 is provided between the first drilling unit 3 and the second drilling unit 4. Both the first drilling unit 3 and the second drilling unit 4 include a pilot hole body 6 and a reaming body 7 that are integrally arranged front and back. The pilot hole body 6 of the first drilling unit 3 extends to the axis at the top of the drilling body 1; a number of pilot hole protruding nozzles 8 and reaming protruding nozzles 9 are provided on the drilling body 1. An inner drill bit cavity is axially penetrated inside the connecting body 2, and the inner drill bit cavity extends to the inside of the drilling body 1. The pilot hole protruding nozzles 8 and the reaming protruding nozzles 9 are respectively connected to the inner drill bit cavity.

[0067] Further, the pilot hole protruding nozzles 8 are arranged on the top of the drilling body 1; the reaming protruding nozzles 9 are arranged in the chip discharge groove 5 between the first drilling unit 3 and the second drilling unit 4 and are at the same height as the transition position from the reaming body 7 to the pilot hole body 6. Further, if the diameter of the pilot hole protruding nozzles 8 and the reaming protruding nozzles 9 is d and the protruding height is h, then 4d ≤ h ≤ 6d. That is, the technical solution adopts an elongated nozzle. This elongated nozzle protrudes a certain distance from the surface of the drilling body 1, and this distance is h, generally 4-6 times the diameter d of the elongated nozzle. Preferably, h = 5d. Additionally, more specifically, on the top of the drilling body 1, three elongated nozzles (pilot hole protruding nozzles 8) are arranged between two adjacent first drilling units 3, and the three elongated nozzles are arranged in a triangular structure.

[0068] Further, the pilot hole body 6 includes a pilot hole section blade 6.1 and a pilot hole section gauge 6.2 that are integrally arranged front and back. The pilot hole section blade 6.1 is provided with a pilot hole cutting tooth unit. The reaming body 7 includes a reaming section blade 7.1 and a reaming section gauge 7.2 that are integrally arranged front and back. The reaming section blade 7.1 is integrally arranged with the pilot hole section gauge 6.2, and the reaming section blade 7.1 is provided with a reaming cutting tooth unit. More specifically, the technical solution adopts a design of six blades in the pilot hole section plus six blades in the reaming section, that is, three first drilling units 3 and three second drilling units 4 are arranged at intervals in the circumferential direction, with a total of six drilling units, that is, there are six reaming section blades 7.1 and six pilot hole section blades 6.1.

[0069] Further, the pilot hole cutting tooth unit includes two rows of pilot hole cutting tooth groups arranged side by side. Each row of pilot hole cutting tooth groups includes a number of pilot hole PDC teeth 6.3 arranged at intervals along the length direction of the pilot hole section blade 6.1. The reaming cutting tooth unit includes two rows of reaming cutting tooth groups arranged side by side. Each row of reaming cutting tooth groups includes a number of reaming PDC teeth 7.3 arranged at intervals along the length direction of the reaming section blade 7.1.

[0070] If the pilot hole body 6 and the reaming body 7 are not integrally arranged, the cuttings formed during drilling will mix and flow between each pilot hole body 6 and each reaming body 7, reducing the cuttings removal efficiency. In response to this, in this technical solution, the pilot hole body 6 and the reaming body 7 are set as a whole, forming a separate channel space between them. The cuttings formed during drilling can smoothly return from the overflow area to the annulus area quickly, effectively improving the cuttings removal efficiency.

[0071] Furthermore, based on the above structure, this technical solution improves the rock-breaking efficiency of the drill bit by means of drilling and reaming in stages. In addition, the rock-breaking speeds of the pilot hole section and the reaming section need to reach a dynamic balance to achieve the purpose of overall speed increase. Otherwise, the pilot hole section and the reaming section will hold each other back. Based on this, related to the characteristics of this technical solution, there are three factors that determine the use effect of the drill bit, namely the pilot-ream ratio, the stage spacing, and the misalignment angle between the cutter blades 6.1 in the pilot hole section and the cutter blades 7.1 in the reaming section.

[0072] Among them, from the direction of the pilot-ream ratio, the drill bit is improved. The pilot-ream ratio refers to the ratio of the outer diameter of the drill bit in the pilot hole section to the outer diameter of the reaming section. Specifically, on the side of the drilling body 1, the radial highest points of the pilot hole bodies 6 in all the first drilling units 3 and the second drilling units 4 are on the same circle; let this circle be the circumcircle of the pilot hole. The radial highest points of the reaming bodies 7 in all the first drilling units 3 and the second drilling units 4 are on the same circle; let this circle be the circumcircle of the reaming. The radius ratio of the circumcircle of the pilot hole to the circumcircle of the reaming is K, that is, the pilot-ream ratio of the drill bit in this technical solution is K, and 0.52 ≤ K ≤ 0.86. Based on this range, the pilot-ream ratio K can be specifically adjusted according to the drillability and destructibility of the rock in the target formation and the relationship between the formation pressure and the liquid column pressure in the wellbore. For example, when considering drilling in the sandstone-shale interbed section, K = 0.83. In this way, it is of great significance to make the mechanical drilling speed in the pilot hole section and the mechanical drilling speed in the reaming section reach a dynamic balance.

[0073] From the direction of the stage spacing, the drill bit is improved. The stage spacing refers to the axial distance between the bottom surface of the pilot hole section and the first tooth in the reaming section. The value of the stage spacing L is related to the diameter of the pilot hole section. Specifically, the diameter of the circumcircle of the pilot hole is D, and the distance from the bottom of the cutter blade 6.1 in the pilot hole section to the top of the reaming cutting tooth unit is L, then 0.4D ≤ L ≤ 1.5D.

[0074] This technical solution designs the cutter blades of the drill bit to have a certain angle difference between the front and rear ends, such as Figure 3As shown in the figure, from the top view, when the drill bit rotates clockwise at the bottom of the well, there is a certain dislocation between the action area of the cutting structure on the front-end blade and the rear end, avoiding the front and rear ends cutting the same row of rocks at the same time, resulting in the superposition of the peak and valley values of the torque change, and reducing the damage of the stick-slip effect to the drill bit. This is particularly obvious for large-sized drill bits. After the improvement of this technical solution, there are two options for selecting the dislocation amplitude: First, the first drilling unit 3 and the second drilling unit 4 are inclined in the same direction, so that there is a phase angle difference θ between the reamer body 7 and the pilot body 6 in the same drilling unit, and 10° ≤ θ ≤ 30°; Second, the pilot body 6 and the reamer body 7 in the same drilling unit are arranged in a circumferential dislocation along the drilling body 1, so that the circumferential dislocation distance between the pilot cutting tooth unit and the reamer cutting tooth unit along the drilling body 1 is N, and 10mm ≤ N ≤ 50mm.

Claims

1. A drilling and reaming integrated bit, characterized in that: It includes a drilling body (1) and a connecting body (2) which are coaxially and integrally arranged front and back; on the side surface of the drilling body (1), a number of first drilling units (3) and second drilling units (4) are arranged at intervals in the circumferential direction. A chip discharge groove (5) is provided between the first drilling unit (3) and the second drilling unit (4). Both the first drilling unit (3) and the second drilling unit (4) include a pilot hole body (6) and a reaming body (7) which are integrally arranged front and back. The pilot hole body (6) of the first drilling unit (3) extends to the axis at the top of the drilling body (1); on the drilling body (1), a number of pilot hole protruding nozzles (8) and reaming protruding nozzles (9) are provided. An inner cavity of the drill bit is axially penetrated inside the connecting body (2), and the inner cavity of the drill bit extends to the inside of the drilling body (1). The pilot hole protruding nozzles (8) and the reaming protruding nozzles (9) are respectively connected to the inner cavity of the drill bit.

2. The integrated drill and reamer bit according to claim 1, wherein: The pilot hole protruding nozzles (8) are arranged at the top of the drilling body (1); the reaming protruding nozzles (9) are arranged in the chip discharge groove (5) between the first drilling unit (3) and the second drilling unit (4), and are at the same height at the position where the reaming body (7) transitions to the pilot hole body (6).

3. The integrated drilling and reaming two-stage bit according to claim 1, characterized in that: The first drilling unit (3) and the second drilling unit (4) are arranged obliquely in the same direction, so that there is a phase angle difference θ between the reaming body (7) and the pilot hole body (6) in the same drilling unit, and 10° ≤ θ ≤ 30°.

4. The reaming and drilling double-stage integrated drill bit according to claim 1, wherein: The pilot hole body (6) includes a pilot hole section cutter wing (6.1) and a pilot hole section gauge (6.2) which are integrally arranged front and back. Pilot hole cutting tooth units are arranged on the pilot hole section cutter wing (6.1).

5. The integrated drill reamer according to claim 4, wherein: The pilot hole cutting tooth units include two rows of pilot hole cutting tooth groups arranged side by side. Each row of pilot hole cutting tooth groups contains a number of pilot hole PDC teeth (6.3) arranged at intervals along the length direction of the pilot hole section cutter wing (6.1).

6. The integrated drilling and reaming two-stage bit according to claim 4, wherein: The reaming body (7) includes a reaming section cutter wing (7.1) and a reaming section gauge (7.2) which are integrally arranged front and back. The reaming section cutter wing (7.1) is integrally arranged with the pilot hole section gauge (6.2), and reaming cutting tooth units are arranged on the reaming section cutter wing (7.1).

7. The reaming and drilling integrated bit according to claim 6, wherein: The reaming cutting tooth units include two rows of reaming cutting tooth groups arranged side by side. Each row of reaming cutting tooth groups contains a number of reaming PDC teeth (7.3) arranged at intervals along the length direction of the reaming section cutter wing (7.1).

8. The integrated drill reamer according to claim 6, wherein: The pilot hole body (6) and the reaming body (7) in the same drilling unit are arranged offset in the circumferential direction of the drilling body (1), so that the offset distance of the pilot hole cutting tooth units and the reaming cutting tooth units in the circumferential direction of the drilling body (1) is N, and 10mm ≤ N ≤ 50mm.

9. The integrated drill and reamer bit according to claim 6, wherein: On the side surface of the drilling body (1), the radially highest points of the pilot hole bodies (6) in all the first drilling units (3) and the second drilling units (4) are on the same circle; let this circle be the pilot hole circumscribed circle. The radially highest points of the reaming bodies (7) in all the first drilling units (3) and the second drilling units (4) are on the same circle; let this circle be the reaming circumscribed circle. The radius ratio of the pilot hole circumscribed circle to the reaming circumscribed circle is K, and 0.52 ≤ K ≤ 0.

86.

10. The integrated drilling and reaming two-stage bit according to claim 9, characterized in that: Let the diameter of the circumscribed circle of the pilot hole be D, and the distance from the bottom of the cutter blade (6.1) in the pilot hole section to the top of the reaming cutting tooth unit be L. Then, 0.4D ≤ L ≤ 1.5D.

11. The integrated drilling and reaming two-stage bit according to claim 1, wherein: Let the diameter of the pilot hole raised nozzle (8) and the reaming raised nozzle (9) be d, and the raised height be h. Then, 4d ≤ h ≤ 6d.

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