CN111411898B

CN111411898B - Composite drill bit

Info

Publication number: CN111411898B
Application number: CN202010464296.8A
Authority: CN
Inventors: 张春亮; 杨迎新; 包泽军; 唐嘉诚; 王不正; 倪平虎
Original assignee: Chengdu Weiyi Petroleum Technology Co ltd; Southwest Petroleum University
Current assignee: Chengdu Weiyi Petroleum Technology Co ltd; Southwest Petroleum University
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2023-06-09
Anticipated expiration: 2040-05-28
Also published as: CN111411898A

Abstract

The composite drill bit comprises a drill bit body, blades, a bit leg and a gear wheel, wherein the blades are fixedly connected with the drill bit body or integrally formed, cutting teeth are arranged on the blades, the gear wheel is rotationally connected with the bit leg through a shaft, and the gear wheel is provided with teeth; 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 can improve the rock breaking efficiency, save the drilling cost and reduce the circumferential vibration of the composite drill bit.

Description

Composite drill bit

Technical Field

The invention relates to the technical fields of petroleum and natural 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, impact, or the like. PDC (Polycrystalline Diamond Compact polycrystalline diamond compact) bits are an important category in the prior art of bits and are increasingly being used in petroleum drilling, geology, and even construction engineering. The PDC drill bit is used for rock breaking in a mode of mainly cutting through cutting teeth arranged on the drill bit, can obtain ideal drilling speed in soft to medium hard stratum, and is widely applied to oil and gas drilling.

With the depletion of shallow hydrocarbon resources, the focus of hydrocarbon exploration development is gradually turned to deep, deep sea, unconventional hydrocarbon (including shale gas). In general, rock materials of deep formations are hard, strong in abrasiveness, and poor in drillability. PDC bits, which drill in these formations, often fail to achieve high rates of penetration, one of the most important of which is limited by the penetration capacity of the cutter. Particularly, as the depth of the formation increases, the complexity of the formation increases, such as hard-plastic formations, hard-brittle formations, hard-soft interlayers, gravel-containing formations, and the like, the cutting teeth cannot effectively penetrate the formation, drilling efficiency is low, and rapid wear of the cutting teeth is easily caused. After excessive wear of the cutting teeth, the workload of adjacent teeth is increased, further interlocking failure of the cutting teeth occurs, and once the cutting teeth in a larger area fail, the cutting capability of the drill bit is basically lost.

In order to solve the problems of low drilling speed and short service life of the drill bit in the complex stratum, researchers have proposed a composite drill bit as early as thirty generations of the nineteenth century, but are limited by the defect of the material performance of cutting teeth, and the composite drill bit cannot be successfully applied until 2010, and has good field application effect. Accordingly, a hot trend of composite drill bit research is started in each country, and products are well popularized and applied in complex and difficult-to-drill stratum around the world. When the composite drill bit works, the teeth on the roller cone are used for invading stratum to break or pre-break rock, and the weakened stratum can be removed by applying smaller energy to the composite sheet, so that the composite drill bit has the advantages of low energy consumption and high rock breaking efficiency when drilling in a complicated difficult-to-drill stratum.

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

Disclosure of Invention

The invention aims to provide a composite drill bit, wherein an impact unit is arranged on the composite drill bit, so that impact rock breaking or pre-damage to a stratum is realized, an impact tool is not required to be independently arranged, the circumferential supporting point of the composite drill bit is increased, meanwhile, 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 in the following way:

a composite drill bit comprises a drill bit body, blades, a bit leg and a gear wheel, wherein the blades are fixedly connected with the drill bit body or integrally formed, cutting teeth are arranged on the blades, the gear wheel is rotationally connected with the bit leg 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 can realize the impact of the impact device through the transmission device.

In the above structure, the rolling element of the impact unit contacts with the rock to generate a rotational moment to rotate during the rock breaking process. The rolling elements are typically cone structures, roller structures, rollers. The rotation of the rolling bodies realizes that the impact device impacts broken or pre-damaged rock along a preset impact direction through the transmission device, and the cutting teeth on the blades have low energy consumption and high efficiency when breaking the weakened stratum. On the one hand, the impact unit can well assist the cutting teeth on the drill bit to break rock, prolong the service life of the cutting teeth, and further prolong the sustainable high-efficiency 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, and tools such as an impactor and the like are not required to be independently arranged, so that the drilling cost is saved. Finally, the rolling bodies also significantly reduce the working torque of the drill bit during drilling.

The bottom hole cover tooth distribution diagram refers to a bottom hole cover tooth distribution diagram formed by collecting cutting contour lines of all cutting teeth together in any axial plane passing through the center line of a drill bit, wherein the cutting contour lines of the cutting teeth rotate around the center line of the drill bit and form intersecting lines with the axial plane, the intersecting lines are cutting contour lines, and the bottom hole cover tooth distribution diagram is shown in fig. 6 or 12 and is a bottom hole cover diagram of a composite drill bit. The bottom hole coverage tooth distribution diagram directly reflects important parameters such as the positioning radius, the positioning height and the like of the cutting tooth.

The impact teeth can be cone teeth, wedge teeth, spoon teeth, spherical teeth and the like, and the materials of the impact teeth comprise artificial polycrystalline diamond, natural diamond, hard alloy, ceramics, cubic boron nitride and the like. The connection mode of the impact teeth and the impact rod can be a threaded connection mode, an interference fit mode, a welding mode, an integrated forming mode or the like.

As a preferred embodiment of the present invention, the drill body is provided with a support body, and the striking unit is provided on the support body. The provision of the support on the drill bit provides more space and design freedom for the provision of the percussion unit. When the supporting body is provided with the blade gauge (refer to fig. 1 and 2), the impact unit is contacted with the well wall, so that the circumferential supporting point of the composite drill bit 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 embodiment of the present invention, the impact unit is provided on the blade. The impact unit is arranged on the cutter blade, so that precious space of the composite drill bit can be saved, and the arrangement mode of the rolling bodies is more flexible. When the rolling bodies are roller cones, the rock breaking capacity is further achieved, and rock breaking efficiency is further improved.

As a preferred embodiment of the present invention, the transmission means is a cam mechanism. The realization and transmission principle of the cam mechanism is described with reference to fig. 3, wherein the cam mechanism comprises a transmission shaft, a cam body at the shaft end and a cam body on the cam body. The rolling bodies are fixedly connected with the transmission shaft or integrally formed, and the convex bodies on the shaft end convex bodies and the impact rod in the impact device form a cam pair in the rotation process of the transmission shaft, so that the impact device can impact along the preset direction through the cam mechanism by the rotation of the rolling bodies. The cam has simple structure, safety and reliability and is easy to implement.

As a preferred embodiment of the invention, the transmission is a gear mechanism. The realization and transmission principle of the gear mechanism are described by referring to fig. 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 bodies drive the transmission shafts and the transmission gears at the bottom ends of the transmission shafts to rotate, the driven gears are meshed with the transmission gears and rotate, the convex bodies on the driven gears and the impact rod in the impact device form a cam pair, and impact teeth impact towards the impact direction. The gear transmission is stable and easy to realize.

As a preferable mode of the invention, the rolling bodies comprise roller cones, rollers and rollers.

As a preferable scheme of the invention, the impact rod is provided with an elastic element, and the elastic element can be a spring, a disc spring, rubber and the like and is used for realizing rebound after the impact rod is impacted. For the impact unit, after the impact teeth complete one impact, the impact unit needs to return in time, and if not, the next impact cannot be successfully completed. The impact rod is easy to realize in elasticity, and the structure is simple and reliable.

As a preferred embodiment of the present invention, the impact teeth are provided in front of or behind the cutting teeth. It is apparent to those skilled in the art that the impact teeth are co-orbital with the cutting teeth.

As a preferred embodiment of the invention, the composite bit has at least one tooth arrangement blank area around the center of the bit, the impact of the impact teeth being oriented in the radial direction of the bit.

The invention at least comprises the following beneficial effects:

1. the impact unit realizes impact under the condition of self rotation of the drill bit without being provided with an impactor tool, thereby saving cost. Meanwhile, the rolling bodies in the impact unit are contacted with the rock 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, the rock crushing efficiency is improved, and the probability of tooth breakage failure of the cutting teeth is reduced;

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

4. In the scheme that the rolling bodies are arranged at the cutter wing gauge, the circumferential support points of the composite drill bit can be increased, 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 needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some examples of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural view 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 an impact 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 view of a rolling element as a roller in an impact unit according to a first embodiment of the present invention.

Fig. 6 is a schematic view showing the meaning of the distance L between the rolling element and the gauge wire of the blade in the impact unit according to the first embodiment of the present invention.

Fig. 7 is a schematic structural view of the impact teeth in the impact unit according to the first embodiment of the present invention.

Fig. 8 is a schematic structural view of an impact unit according to a second embodiment of the present invention, wherein the transmission structure is a gear structure.

Fig. 9 is a schematic diagram of the impact tooth and cutting tooth breaking rock in an in-orbit 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 bit body; 3-blades; 30-rolling grooves; 31-cutting teeth; 32-impingement holes; 4-blade gauge protection; 40-knife wing gauge wire; 5-a support; 51-a support matrix; 52-a support complex; 53-a drive hole; a 6-impingement unit; 61-rolling elements; 62-transmission device; 63-an impact device; 610-rolling the outer profile; 621-a transmission shaft; 622-convex body; 623-a cam body; 631-impact teeth; 632-impact bar; 7-tooth arrangement blank areas; 71-a rock ridge; 8-an elastic element; 81-springs; 82-disc springs; 91-a transmission gear; 92-driven gear; 10-bit leg; 11-cone; 111-teeth.

Detailed Description

For the purpose of making 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 clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention. Thus, the following detailed description of the embodiments of the invention, as 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, based on the embodiments of the invention, which are apparent to those of ordinary skill in the art without inventive faculty, are intended to be within the scope of the invention.

First embodiment:

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

The utility model provides a composite drill bit 1, includes bit body 2, wing 3, bit leg 10, cone 11, and the fixed continuous or integrated into one piece of wing 3 and bit body 2 is provided with cutting teeth 31 on the wing 3, and the cone 11 forms the rotation through the axle with bit leg 10 and is connected, is provided with tooth 111 on the cone 11, is provided with impact unit 6 on the composite drill bit 1 through support body 5.

Referring to fig. 3 to 6, the impact unit 6 is composed of a rolling body 61, a transmission 62 and an impact device 63; the rolling body 61 can rotate around the axis of the rolling body 61, and in the bottom hole coverage diagram (refer to fig. 6), the distance between the outer contour 610 of the rolling body 61 and the blade gauge wire 40 in the radial direction is L, the range is-d/4-L-d/4, and d is the diameter of the cutting teeth; the impact device 63 consists of an impact rod 632 and at least one impact tooth 631; the rotation of the rolling bodies 61 enables the impact device 63 to impact in the impact direction by means of the transmission device 62. To facilitate the mounting of the impact unit 6, the support body 5 is provided as a separate body (partly a support body base 51 and partly a support body mating body 52), see fig. 4.

In the embodiment of the invention, the rolling bodies 61 of the impact unit 6 are of a roller cone structure, and the roller cones are contacted with rock to generate a rotational moment to rotate in the rock breaking process. The rolling elements 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 protrusion 622 on the cam body 623. The rolling body 61 is fixedly connected with the transmission shaft 621 or integrally formed, the transmission shaft 621 is arranged in the transmission hole 53 of the supporting body 5, the convex body 622 on the shaft end cam body 623 and the impact rod 632 in the impact device 63 form a cam pair during rotation, and the impact rod 632 is arranged in the impact hole 32 of the blade, so that the impact device 63 can impact along the preset direction through the cam mechanism during rotation of the rolling body 61. The connection between the cam body 623 and the drive shaft 621 includes an excessively hard fit, a threaded connection, welding, integral molding, etc. The cam has simple structure, safety and reliability and is easy to implement. For the impact unit, after the impact teeth 631 complete an impact, a return stroke is required, and if the impact teeth cannot complete the next impact (stroke), in order to achieve this purpose, the impact rod 632 of the embodiment of the present invention is provided with an elastic element 8, where the elastic element 8 may be a spring 81 (see fig. 3), a disc spring 82 (see fig. 8), rubber, etc., and the elastic element 8 is used to achieve rebound after the impact device 63 completes the impact. The elastic element 8 provided on the impact rod 632 in this embodiment is easy to implement and has a simple and reliable structure.

The impact teeth 631 may be cone teeth (see fig. 1-4, 8, 10 and 11), wedge teeth (see fig. 7), spoon teeth, ball teeth, etc., and the impact teeth 631 may be made of artificial polycrystalline diamond, natural diamond, cemented carbide, ceramics, cubic boron nitride, etc. The connection mode of the impact teeth 631 and the impact rod 632 can be a threaded connection mode, an interference fit mode, a welding mode, an integral forming mode or the like, and in this example, the integral forming mode is adopted.

It will be readily appreciated by those skilled in the art that the impingement teeth 631 may be disposed forward of, rearward of, or both forward and rearward of the cutting teeth 31. Among the solutions in which the impact tooth 631 is arranged in front of the cutting tooth 31, there is a more preferable solution, i.e. the impact tooth 631 is designed in co-orbit with the cutting tooth 31. Referring to fig. 8, when the impact teeth 631 and the cutting teeth 31 are designed in the same track, the two in the bottom hole coverage map have the same positioning radius, the impact teeth 631 impact the rock first, the rock forms pre-damage, micro-cracks are generated inside, and the energy consumption of breaking the damaged stratum by the cutting teeth 31 following the track rotation is smaller.

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

1. the impact unit 6 achieves impact under the condition of self rotation of the drill bit without being provided with an impactor tool, thereby saving cost. Meanwhile, the impact unit 6 is arranged at the position of the blade gauge 4, the rolling body 61 on the impact unit is in contact with the well wall, the circumferential supporting point of the composite drill bit is increased, and meanwhile, the working torque of the drill bit in the drilling process is further reduced;

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

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 1 of substantially the same structure as the composite drill bit 1 of the first embodiment, the difference being that: 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 protrusion 622 on the driven gear 92, wherein the transmission shaft 621 is fixedly connected or integrally formed with the rolling body 61, and the transmission gear 91 is fixedly connected or integrally formed with the transmission shaft 621. In 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.

Third embodiment:

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

The impact unit 6 is composed of rolling elements 61, a transmission 62 and an impact device 63; the rolling bodies 61 can rotate around the axes thereof and are arranged in the rolling grooves 30 of the blades 3; the impact device 63 consists of an impact rod 632 and at least one impact tooth 631; the rotation of the rolling bodies 61 enables the impact means 63 to impact in the radial direction of the composite drill bit 1 by means of the transmission means 62.

In the above scheme, the tooth arrangement blank area 7 is at the center of the drill bit, the corresponding raised rock ridge 71 is formed at the bottom of the well in the well working, and the restraint of the rock originally received around the rock ridge 71 is relieved, so that the strength of the rock ridge 71 is obviously reduced, which is equivalent to an isolated wall body or column body. In fact, the protruding ridges 71 will run in the same direction as the drilling or bit axis, and when the impact direction of the impact teeth 631 is in the radial direction of the bit, the impact teeth 631 impact the isolated ridges 71 at an angle, the crushing energy consumption will be greatly reduced, and the crushing mode will be more prone to volumetric crushing, and the rock breaking efficiency will be further improved.

Claims

1. The composite drill bit comprises a drill bit body, blades, a bit leg and a gear wheel, wherein the blades are fixedly connected with the drill bit body or integrally formed, cutting teeth are arranged on the blades, and the gear wheel is rotationally connected with the bit leg through a shaft; the rolling bodies can rotate around the axis of the rolling bodies; the impact device consists of an impact rod and at least one impact tooth; the rotation of the rolling bodies can realize the impact of the impact device through the transmission device; the impact unit is arranged on the blade.

2. A composite drill bit according to claim 1, wherein the bit body is provided with a support body, and the striking unit is provided on the support body.

3. The composite drill bit of claim 1, wherein the transmission is a cam mechanism.

4. The composite drill bit of claim 1, wherein the transmission is a gear mechanism.

5. The composite drill bit of claim 1, wherein the rolling elements comprise cones, rollers or rollers.

6. A composite drill bit according to claim 1, wherein the impact rod is provided with an elastic element; the elastic element comprises a spring, a disc spring or rubber; the elastic element is used for realizing rebound after the impact device finishes impact.

7. The composite drill bit of claim 1, wherein the impact teeth are disposed forward or aft of the cutting teeth.

8. 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.

9. The composite drill bit of claim 1, wherein the percussive teeth comprise cone, wedge, scoop or ball type teeth; the material of the impact teeth comprises artificial polycrystalline diamond, natural diamond, hard alloy, ceramic or cubic boron nitride.