阅读说明：本技术 一种复合钻头 (Composite drill bit ) 是由 张春亮 杨迎新 包泽军 唐嘉诚 王不正 倪平虎 于 2020-05-28 设计创作，主要内容包括：一种复合钻头,包括钻头本体、刀翼、牙掌、牙轮,刀翼与钻头本体固定相连或一体成型,刀翼上设置有切削齿,牙轮与牙掌通过轴形成转动连接,牙轮上设置有牙齿,其特征在于,在复合钻头上设置有冲击单元,冲击单元由滚动体、传动装置和冲击装置构成；滚动体能绕自身轴线转动；冲击装置由冲击杆和至少一个冲击齿组成。本发明在提高破岩效率的同时,节约钻井成本,还能减少复合钻头周向振动。(A composite drill bit comprises a drill bit body, blades, a bit leg and a cone, wherein the blades are fixedly connected with the drill bit body or integrally formed, cutting teeth are arranged on the blades, the cone is rotatably connected with the bit leg through a shaft, and teeth are arranged on the cone; the rolling body can rotate around the axis of the rolling body; the impact device consists of an impact rod and at least one impact tooth. The invention improves the rock breaking efficiency, saves the drilling cost and can reduce the circumferential vibration of the composite drill bit.)

1. A composite drill bit comprises a drill bit body, blades, a bit leg and a cone, wherein the blades are fixedly connected with the drill bit body or integrally formed, cutting teeth are arranged on the blades, and the cone is rotationally connected with the bit leg through a shaft; the rolling body can rotate around the axis of the rolling body; the impact device consists of an impact rod and at least one impact tooth; the rotation of the rolling bodies enables the impact of the impact device to be achieved by means of a transmission.

2. A composite drill bit according to claim 1, characterized in that a support body is provided on the drill bit body, the percussion unit being provided on the support body.

3. A composite drill bit according to claim 1, characterized in that the percussion unit is arranged on the blade.

4. A composite drill bit according to claim 1, wherein the transmission is a cam mechanism.

5. A composite drill bit according to claim 1, wherein the transmission is a gear mechanism.

6. A composite drill bit according to claim 1, wherein the rolling elements comprise cones, rollers.

7. A composite drill bit according to claim 1, wherein the impact rod is provided with a resilient element; the elastic element comprises a spring, a disc spring and rubber; the elastic element is used for realizing the rebound of the impact device after the impact is finished.

8. A composite drill bit according to claim 1, wherein the impact teeth are disposed forward or rearward of the cutting teeth.

9. A composite drill bit according to claim 1, wherein the drill bit has at least one tooth space around the center of the drill bit; the impact direction of the impact teeth is the radial direction of the drill bit.

10. The composite drill bit of claim 1, wherein the impact teeth comprise tapered teeth, wedge teeth, spoon teeth, ball teeth; the material of the impact tooth comprises artificial polycrystalline diamond, natural diamond, hard alloy, ceramic and cubic boron nitride.

Technical Field

The invention relates to the technical fields of oil and gas drilling engineering, mining engineering, geological drilling, tunnel engineering and the like, in particular to a composite drill bit.

Background

A drill bit is a tool that directly contacts rock during drilling and breaks the rock by cutting, impacting, etc. PDC (Polycrystalline Diamond Compact) bits, which are an important type of existing bit technologies, are increasingly used in oil drilling, geological and even construction. The PDC drill bit mainly cuts rock through cutting teeth arranged on the drill bit, can obtain ideal drilling rate in soft to medium hard strata, and is widely applied to oil and gas drilling.

With the development of shallow oil and gas resources being almost exhausted, the emphasis of oil and gas exploration and development gradually shifts to deep-layer, deep-sea and unconventional oil and gas (including shale gas). Typically, the rock material of deep formations is hard, abrasive and poorly drillable. PDC bits, drilling in these formations, often fail to achieve high rates of penetration, one of the most important reasons being limited by the cutting tooth's penetration capability. Particularly, with the increase of the depth of the stratum, the complexity of the stratum is higher and higher, such as a hard-plastic stratum, a hard-brittle stratum, a soft-hard interlayer, a gravel-containing stratum and the like, the cutting teeth cannot effectively bite into the stratum, the drilling efficiency is low, and the rapid abrasion of the cutting teeth is easily caused. Excessive wear of the cutting teeth increases the workload of adjacent teeth, and consequently, cascading failure of the cutting teeth occurs, and once the cutting teeth fail in a larger area, the cutting ability of the drill bit is substantially lost.

In order to solve the problems of slow drilling speed and short service life of the drill bit in the complex stratum, researchers have proposed the composite drill bit early in the thirties early in the nineteenth century, but the composite drill bit is limited by the defects of the material performance of the cutting teeth, the composite drill bit cannot be successfully applied until 2010, and a good field application effect is achieved. Accordingly, the research of the composite drill bit is hot in all countries, and the product is well popularized and applied to complex and difficult-to-drill stratums around the world. When the composite drill bit works, the composite drill bit invades the stratum by means of teeth on the roller cone, and crushes or pre-crushes rocks, and the weakened stratum can be removed by the composite sheet with smaller energy, so that the composite drill bit has the advantages of low energy consumption and high rock crushing efficiency when drilling in a complex and difficult-to-drill stratum.

In order to further improve the problems of low composite drill bit invasion capacity, low rock breaking efficiency, short service life and the like in the difficult-to-drill stratum, a plurality of workers of scientific research units or drill bit production enterprises try to use impacter tools (such as axial impactors and torsional impactors) together with drill bits. By the method, the drill bit generates small impact in the drilling process so as to realize the sudden stress application of the cutting teeth in the action process with the rock, the rock stress at the bottom of the well is greatly released, and the cutting teeth biting capacity is improved. However, the impact generated by the impactor acts directly on the entire drill bit. Generally, the cutting teeth mounted on the drill bit are polycrystalline diamond compacts, the impact resistance of the cutting teeth is relatively weak, and when impact load of an impactor is applied to the drill bit, the impact between the cutting teeth on the drill bit and rock is easy to cause the breaking-out failure of part of the cutting teeth. In addition, the existing rock-breaking impact technology is generally a tool string combination of an impactor and a drill bit, and needs to be added with impact equipment separately, so that the drilling cost is high.

Disclosure of Invention

The invention aims to provide a composite drill bit, wherein the composite drill bit is provided with an impact unit, so that when rock breaking is impacted or a stratum is pre-damaged, an impactor tool is not required to be independently arranged, the circumferential support point of the composite drill bit is increased, the working torque of the drill bit is further reduced, the rock breaking efficiency is improved, and the drilling cost is saved.

The invention is realized by the following steps:

a composite drill bit comprises a drill bit body, blades, a bit leg and a cone, wherein the blades are fixedly connected with the drill bit body or integrally formed, cutting teeth are arranged on the blades, the cone and the bit leg are in rotary connection through a shaft, an impact unit is arranged on the composite drill bit, and the impact unit consists of a rolling body, a transmission device and an impact device; the rolling body can rotate around the axis of the rolling body; the impact device consists of an impact rod and at least one impact tooth; the rotation of the rolling bodies enables the percussion of the percussion device by means of a transmission.

In the structure, the rolling bodies of the impact unit are contacted with rocks in the rock breaking process to generate rotation torque to rotate. The rolling elements are typically cone structures, roller structures, rollers. The autorotation of the rolling body realizes that the impact device impacts and breaks or pre-damages rocks along a preset impact direction through the transmission device, and when cutting teeth on the blades break weakened strata, the energy consumption is low, and the efficiency is high. On the one hand, the impact unit can well assist the cutting teeth on the drill bit to break rocks, prolong the service life of the cutting teeth, and further prolong the sustainable and efficient drilling capability of the drill bit. On the other hand, the impact work formed by the impact unit only depends on the revolution of the drill bit, tools such as an impactor and the like do not need to be arranged independently, and the drilling cost is saved. Finally, the rolling elements also significantly reduce the working torque during drilling of the drill bit.

The bottom hole coverage tooth distribution diagram refers to that in any axial plane passing through the central line of the drill bit, the cutting profiles of the cutting teeth rotate around the central line of the drill bit and form an intersection line with the axial plane, the intersection line is a cutting profile line, and the cutting profile lines of all the cutting teeth are gathered together to form the bottom hole coverage tooth distribution diagram, such as the bottom hole coverage diagram of the composite drill bit shown in fig. 6 or fig. 12. The bottom hole covering tooth distribution diagram directly reflects the important parameters of the positioning radius, the positioning height and the like of the cutting tooth.

The impact teeth can be conical teeth, wedge-shaped teeth, spoon-shaped teeth, spherical teeth and the like, and the materials of the impact teeth comprise artificial polycrystalline diamond, natural diamond, hard alloy, ceramic, cubic boron nitride and the like. The connection mode of the impact teeth and the impact rod can be threaded connection, interference fit, welding, integral forming or the like.

In a preferred embodiment of the present invention, the drill body is provided with a support body, and the impact unit is provided on the support body. The support body arranged on the drill bit can provide more space and design freedom for arranging the impact unit. When the supporting body is provided with the drill bit gauge protection part (please refer to fig. 1 and fig. 2), the impact unit is contacted with the well wall, so that the supporting points of the composite drill bit in the circumferential direction can be increased, the circumferential vibration generated in the drill bit movement process is reduced, and meanwhile, the working torque of the composite drill bit is further reduced.

As a preferred aspect of the present invention, the impact unit is provided on the blade. The impact unit is arranged on the blade, so that the valuable space of the composite drill bit can be saved, and the arrangement mode of the rolling body is more flexible. When the rolling body is a cone, the rock breaking capacity is achieved, and the rock breaking efficiency is further improved.

In a preferred embodiment of the present invention, the transmission is a cam mechanism. The implementation and transmission principle of the cam mechanism will be described with reference to fig. 3, and the cam mechanism includes a transmission shaft, a cam body at the shaft end, and a convex body on the cam body. The rolling body is fixedly connected with the transmission shaft or integrally formed, and the convex body on the shaft end cam body and the impact rod in the impact device form a cam pair in the rotation process of the transmission shaft, so that the rotation of the rolling body can realize the impact of the impact device along the preset direction through the cam mechanism. The cam has simple structure, safety, reliability and easy implementation.

In a preferred embodiment of the present invention, the transmission is a gear mechanism. The realization and transmission principle of the gear mechanism are explained by combining with the attached figure 9, the gear mechanism comprises a transmission shaft, a transmission gear, a driven gear and a convex body on the driven gear, the transmission shaft is fixedly connected with or integrally formed with the rolling body, and the transmission gear is fixedly connected with or integrally formed with the transmission shaft. When the impact device works, the rolling body drives the transmission shaft and the transmission gear at the bottom end of the transmission shaft to rotate, the driven gear is meshed with the transmission gear and rotates, and the convex body on the driven gear and the impact rod in the impact device form a cam pair to realize impact of the impact teeth towards the impact direction. The gear transmission is stable and easy to realize.

In a preferred embodiment of the present invention, the rolling elements include cones, rollers, and rollers.

As a preferred embodiment of the present invention, the impact bar is provided with an elastic element, which may be a spring, a disc spring, rubber, or the like, and the elastic element is used to realize the rebound of the impact bar after the impact is completed. For the impact unit, after the impact tooth completes one impact, the impact tooth needs to return in time, and if not, the impact tooth cannot complete the next impact smoothly. The elasticity arranged on the impact rod is easy to realize, and the structure is simple and reliable.

As a preferable aspect of the present invention, the impact teeth are provided in front of or behind the cutting teeth. It is apparent that those skilled in the art will readily appreciate that the impact teeth are of the same orbital design as the cutting teeth.

As a preferable scheme of the invention, the composite drill bit is provided with at least one tooth arrangement blank area surrounding the center of the drill bit, and the impact direction of the impact teeth is the radial direction of the drill bit.

The invention at least comprises the following beneficial effects:

1. the impact unit realizes impact under the condition of relying on the rotation of the drill bit without being provided with an impactor tool, so that the cost is saved. Meanwhile, the rolling bodies in the impact units are in contact with rocks at the bottom of the well, so that the working torque of the drill bit in the drilling process can be further reduced;

2. the impact action of the impact unit further forms impact crushing or pre-damage to the rock, the energy consumption of the cutting teeth is smaller when the weakened stratum is crushed, and the probability of tooth breakage failure of the cutting teeth is reduced while the rock crushing efficiency is improved;

3. when the transmission device in the impact unit adopts a cam mechanism or a gear transmission mechanism, the impact unit has simple structure, safety, reliability and easy implementation.

4. In the scheme that the rolling bodies are arranged at the gauge protection position of the drill bit, the circumferential support points of the composite drill bit can be increased, the circumferential vibration in the drilling process is reduced, and the sustainable drilling capability of the drill bit is further improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic structural diagram of a composite drill bit according to a first embodiment of the present invention.

Fig. 2 is a top view of fig. 1.

Fig. 3 is a schematic structural view of a percussion unit on a composite drill bit according to a first embodiment of the present invention.

Fig. 4 is a partial cross-sectional view of fig. 2.

Fig. 5 is a schematic structural diagram of a roller as a rolling body in an impact unit according to a first embodiment of the present invention.

Fig. 6 is a schematic diagram showing the meaning of the rolling element-to-gauge distance L in the impact unit provided by the first embodiment of the present invention.

Fig. 7 is a schematic structural view of an impact unit in which impact teeth are wedge-shaped teeth according to a first embodiment of the present invention.

Fig. 8 is a schematic structural diagram of an impact unit provided in a second embodiment of the present invention, wherein the transmission structure is a gear structure.

Fig. 9 is a schematic illustration of the principle of rock breaking with an impact tooth and a cutting tooth of the same orbital design.

Fig. 10 is a schematic structural view of a composite drill bit according to a third embodiment of the present invention.

Fig. 11 is a top view of fig. 10.

FIG. 12 is a schematic view of the bottom hole coverage of FIG. 10.

Icon: 1-a composite drill bit; 2-a drill bit body; 3-a blade; 30-rolling grooves; 31-a cutting tooth; 32-impingement holes; 4-protecting the diameter of the blade; 5-a support; 51-a support matrix; 52-a support conjugate; 53-drive hole; 6-impact unit mating body; 61-rolling bodies; 62-a transmission; 63-an impact device; 610-outer contour of rolling body; 621-a transmission shaft; 622-convex body; 623-a cam body; 631-impact teeth; 632-impact bar; 7-laying tooth blank areas; 71-a ridge of rock; 8-a resilient element; 81-spring; 82-disc spring; 91-a transmission gear; 92-a driven gear; 10-bit leg; a 11-cone; 111-teeth.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The first embodiment:

referring to fig. 1-8, a composite drill bit 1 is provided according to an embodiment of the present invention.

A composite drill bit 1 comprises a bit body 2, blades 3, a bit leg 10 and a cone 11, wherein the blades 3 are fixedly connected with the bit body 2 or integrally formed, cutting teeth 31 are arranged on the blades 3, the cone 11 and the bit leg 10 are in rotary connection through a shaft, teeth 111 are arranged on the cone 11, and an impact unit 6 is arranged on the composite drill bit 1 through a supporting body 5.

Referring to fig. 3-6, the impact unit 6 is composed of a rolling body 61, a transmission device 62 and an impact device 63, the rolling body 61 can rotate around its axis, in a shaft bottom overlay (see fig. 6), the distance between the outer contour 610 of the rolling body 61 and the blade gauge line 40 in the radial direction is L, the range is-d/4 ≤ L ≤ d/4, d is the diameter of a cutting tooth, the impact device 63 is composed of an impact rod 632 and at least one impact tooth 631, the rotation of the rolling body 61 can realize impact of the impact device 63 along the impact direction through the transmission device 62, the support body 5 is arranged as a split type (a part is a base body 51 and a part is a matching body 52) for facilitating the installation of the impact unit 6, and refer to fig. 4.

In the embodiment of the invention, the rolling body 61 of the impact unit 6 is of a cone structure, and the cone contacts with rock to generate a rotation torque and rotate in the rock breaking process. The rolling bodies 61 may also be rollers (see fig. 5) or rollers.

Referring to fig. 3 and 4, the transmission device 62 is a cam mechanism, and the cam mechanism includes a transmission shaft 621, a cam body 623 at the shaft end, and a convex body 622 on the cam body 623. The rolling body 61 is fixedly connected with or integrally formed with a transmission shaft 621, the transmission shaft 621 is arranged in a transmission hole 53 of the support body 5, a convex body 622 on the shaft end cam body 623 and an impact rod 632 in the impact device 63 form a cam pair in the rotating process, and the impact rod 632 is arranged in an impact hole 32 of the blade, so that the impact device 63 can impact along a preset direction through a cam mechanism by the rotation of the rolling body 61. The connection between the cam body 623 and the transmission shaft 621 includes over-hard fitting, screwing, welding, integral molding, etc. The cam has simple structure, safety, reliability and easy implementation. For the impact unit, after the impact teeth 631 complete one impact, the impact gear needs to return, and if the impact gear cannot complete the next impact (stroke), in order to achieve the purpose, the impact rod 632 in the embodiment of the present invention is provided with the elastic element 8, the elastic element 8 may be a spring 81 (see fig. 3), a disc spring (see fig. 8), rubber, or the like, and the elastic element 8 is used for realizing the rebound after the impact device 63 completes the impact. The elastic element 8 provided on the striking rod 632 in this embodiment is easy to implement and has a simple and reliable structure.

The impact teeth 631 may be tapered teeth (see fig. 1-4, 8, 10, and 11), wedge-shaped teeth (see fig. 7), spoon-shaped teeth, ball-shaped teeth, etc., and the impact teeth 631 may be made of synthetic polycrystalline diamond, natural diamond, cemented carbide, ceramic, cubic boron nitride, etc. The connection between the striking teeth 631 and the striking rod 632 may be a threaded connection, an interference fit, a welding connection, or an integral molding, in this example, an integral molding.

It will be readily appreciated by those skilled in the art that the impact teeth 631 may be disposed in front of the cutting teeth 31, or behind the cutting teeth 31, or both in front of and behind the cutting teeth 31. In the case of the arrangement of the impact tooth 631 in front of the cutting tooth 31, a more advantageous arrangement is to provide the impact tooth 631 with the same orbital design as the cutting tooth 31. Referring to fig. 8, when the impact tooth 631 and the cutting tooth 31 are designed to have the same orbit, the two have substantially the same positioning radius in the bottom hole overlay, the impact tooth 631 firstly impacts the rock, the rock is pre-damaged, micro-cracks are generated inside, and the energy consumption for breaking the damaged stratum by the cutting tooth 31 following the rotation of the orbit is smaller.

The PDC drill bit provided by the embodiment of the invention has the beneficial effects that:

1. the impact unit 6 realizes impact under the condition of relying on the rotation of the drill bit without being provided with an impactor tool, and the cost is saved. Meanwhile, the impact unit 6 is arranged at the gauge 4 of the drill bit, and the rolling bodies 61 on the impact unit are in contact with the well wall, so that the working torque of the drill bit in the drilling process is further reduced while the circumferential supporting points of the composite drill bit are increased;

2. the impact action of the impact unit 6 can impact and crush or pre-damage the rock, the energy consumption of the cutting teeth 31 of the drill bit is low when the weakened stratum is crushed, and the probability of tooth breakage failure of the cutting teeth 31 is reduced while the rock breaking efficiency is improved;

3. the transmission device 62 in the impact unit 6 is a cam mechanism, and has the advantages of simple and easy structure, safety, reliability and easy implementation.

Second embodiment:

the embodiment of the present invention provides a composite drill bit, and the structure of this PDC drill bit 1 is substantially the same as that of the PDC drill bit 1 in the first embodiment, and the differences are: referring to fig. 9, in the present embodiment, the transmission device 62 is a gear mechanism, and includes a transmission shaft 621, a transmission gear 91, a driven gear 92, and a convex body 622 on the driven gear 92, wherein the transmission shaft 621 is fixedly connected to or integrally formed with the rolling body 61, and the transmission gear 91 is fixedly connected to or integrally formed with the transmission shaft 621. During operation, the rolling body 61 drives the transmission shaft 621 and the transmission gear 91 at the bottom end of the transmission shaft 621 to rotate, the driven gear 92 is meshed with the transmission gear 91 and rotates, the convex body 622 on the driven gear 92 and the impact rod 632 in the impact device 63 form a cam pair, and impact of the impact teeth 631 towards the impact direction is realized. The gear transmission is stable and easy to realize.

The third embodiment:

referring to fig. 10-12, a composite drill bit 1 includes a bit body 2, blades 3, a bit leg 10, and a cone 11, wherein the blades 3 are fixedly connected to or integrally formed with the bit body 2, the blades 3 are provided with cutting teeth 31, the cone 11 is rotatably connected to the bit leg through a shaft, the cone 11 is provided with teeth 111, the bit 1 is provided with at least one tooth distribution blank region 7 surrounding the center of the bit, and the blades 3 are provided with an impact unit 6.

The striking unit 6 is composed of rolling bodies 61, a transmission 62 and a striking device 63; the rolling body 61 can rotate around the axis thereof and is arranged in the rolling groove 30 of the blade 3; the impact device 62 is composed of an impact rod 632 and at least one impact tooth 631; the rotation of the rolling bodies 61 enables the percussion device 63 to strike in the radial direction of the drill bit 1 via the transmission 62.

In the above scheme, the tooth arrangement blank space 7 is at the center of the drill bit, and a corresponding raised ridge 71 is formed at the bottom of the well during the operation at the bottom of the well, so that the original restriction of the rock around the ridge 71 is removed, and the strength of the ridge 71 is remarkably reduced, which is equivalent to an isolated "wall" or "column". In fact, the convex rock ridges 71 run along the axial direction of the drilling or drill bit, when the impact direction of the impact teeth 631 faces the radial direction of the drill bit, the impact teeth 631 impact the isolated rock ridges 71 at a certain angle, the energy consumption for crushing is greatly reduced, and the crushing mode of the rock is more prone to volume crushing, so that the rock crushing efficiency is further improved.