CN111411898B - A composite drill bit - Google Patents

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

A composite drill bit

technical field

The invention relates to technical fields such as petroleum and natural gas drilling engineering, mining engineering, geological drilling, tunnel engineering, etc., and specifically relates to a composite drill bit.

Background technique

The drill bit is a tool that directly contacts the rock during the drilling process and breaks the rock through cutting and impacting. PDC (Polycrystalline Diamond Compact) drill bits, as an important type of existing drill bit technology, are more and more widely used in oil drilling, geology and even construction engineering. The PDC drill bit breaks rock mainly by cutting through the cutting teeth on the drill bit. In soft to medium hard formations, it can obtain ideal drilling speed and has been widely used in oil and gas drilling.

With the development of shallow oil and gas resources exhausted, the focus of oil and gas exploration and development has gradually shifted to deep, deep sea, and unconventional oil and gas (including shale gas). Typically, rock materials in deep formations are hard, abrasive, and poorly drillable. PDC drill bits, when drilling in these formations, often cannot obtain high ROP. One of the most important reasons is that they are limited by the cutting ability of the cutting teeth. Especially as the depth of the formation increases, the complexity of the formation becomes higher and higher, such as hard-plastic formation, hard-brittle formation, soft-hard interlayer, gravel-bearing formation, etc., the cutting teeth cannot effectively penetrate into the formation, and the drilling efficiency is low , and it is easy to cause rapid wear of the cutting teeth. Excessive wear of the cutting teeth will increase the workload of the adjacent teeth, and then the chain failure of the cutting teeth will occur. Once the cutting teeth in a large area fail, the cutting ability of the drill bit will be basically lost.

In order to solve the above-mentioned problems of slow drilling speed and short life of drill bits in complex formations, researchers proposed composite drill bits as early as the early 1830s, but they were not successful until 2010 due to the lack of performance of cutting tooth materials. application, and achieved good field application results. Subsequently, various countries started an upsurge in the research of composite drill bits, and the products have been well promoted and applied in complex and difficult-to-drill formations all over the world. When the composite drill bit is working, it relies on the teeth on the cones to invade the formation, break or pre-break the rock, and the composite sheet can remove the weakened formation with a small amount of energy. Therefore, the composite drill bit has the ability to drill in complex and difficult formations. The advantages of low power consumption and high rock breaking efficiency.

In order to further improve the penetration ability of composite drill bits in difficult-to-drill formations, low rock breaking efficiency, and short service life, many staff members of scientific research institutes or drill bit manufacturers have tried to use impactor tools (such as axial impactors, torsional impactors, etc.) ) is used with a drill. This method makes the drill bit produce a small impact during the drilling process, so as to achieve the sudden force of the cutting teeth in the process of interacting with the rock, the stress of the rock at the bottom of the well is greatly released, and the cutting ability of the cutting teeth is improved. However, the impact generated by the impactor acts directly on the entire drill bit. Usually, the cutting teeth installed on the drill bit are polycrystalline diamond composite sheets, and the impact resistance of these cutting teeth is relatively weak. It is easy to cause the collapse and failure of some cutting teeth. In addition, the existing impact rock breaking technology is usually a tool string combination of impactor and drill bit, which requires additional impact equipment separately, and the drilling cost is relatively high.

Contents of the invention

The object of the present invention is to provide a composite drill bit, the composite drill bit is provided with an impact unit, while realizing impact rock breaking or pre-damaging the stratum, it does not need to be equipped with a separate impactor tool, while increasing the composite drill bit circumferential support point, further Reduce the working torque of the drill bit, improve the rock breaking efficiency and save the drilling cost.

The present invention is achieved like this:

A composite drill bit, comprising a drill body, a blade, a tooth palm, and a cone, the blade is fixedly connected to the drill body or integrally formed, the blade is provided with cutting teeth, the cone and the tooth palm form a rotational connection through a shaft, the composite drill An impact unit is arranged on the top, and the impact unit is composed of a rolling body, a transmission device and an impact device; the rolling body can rotate around its own axis; the impact device is composed of an impact rod and at least one impact tooth; the rotation of the rolling body can be achieved by the transmission device. shock.

In the above structure, the rolling body of the impact unit contacts with the rock during the rock-breaking process to generate a rotational moment and rotate itself. The rolling elements are usually toothed wheel structures, roller structures, and rollers. The rotation of the rolling body realizes the impact device through the transmission device to impact and break or pre-damage the rock along the preset impact direction. The cutting teeth on the blade have low energy consumption and high efficiency when breaking these weakened formations. On the one hand, the impact unit can well assist the cutting teeth on the drill bit to break rocks, prolong the working life of the cutting teeth, and thus extend the sustainable and efficient drilling capability of the drill bit. On the other hand, the percussion work formed by the percussion unit only needs to rely on the revolution of the drill bit, and does not need to be equipped with tools such as impactors separately, which saves drilling costs. Finally, the rolling elements also significantly reduce the operating torque of the bit during drilling.

Bottom hole coverage tooth arrangement diagram means that in any axial plane passing through the centerline of the drill bit, the cutting contour of the cutting teeth rotates around the centerline of the drill bit and forms an intersection line with the axial plane. The intersection line is the cutting contour line. The cutting contours of the cutting teeth are brought together to form the bottom hole coverage map, as shown in Figure 6 or Figure 12 is the bottom hole coverage map of the composite drill bit. The well bottom coverage tooth layout map directly reflects important parameters such as the positioning radius and positioning height of the cutting teeth.

The impact teeth can be cone-shaped teeth, wedge-shaped teeth, spoon-shaped teeth, spherical teeth, etc. The materials of the impact teeth include artificial polycrystalline diamond, natural diamond, hard alloy, ceramics, cubic boron nitride, etc. The connection between the impact tooth and the impact rod can be threaded connection, interference fit, welding, or integral molding.

As a preferred solution of the present invention, a supporting body is arranged on the drill bit body, and the impact unit is arranged on the supporting body. Setting the supporting body on the drill bit can provide more space and design freedom for the setting of the impact unit. When the supporting body is provided with the blade gage (see Figure 1 and Figure 2), the impact unit is in contact with the well wall, which can increase the support point of the composite drill bit in the circumferential direction and reduce the circumferential vibration generated during the movement of the drill bit. Further reduce the operating torque of the compound drill.

As a preferred solution of the present invention, the impact unit is arranged on the blade. The impact unit is arranged on the blade, which can save the precious space of the compound drill bit, and the arrangement of the rolling elements is more flexible. When the rolling element is a toothed wheel, it also has the rock-breaking ability, further improving the rock-breaking efficiency.

As a preferred solution of the present invention, the transmission device is a cam mechanism. The implementation and transmission principle of the cam mechanism will be described in conjunction with accompanying drawing 3. The cam mechanism includes a transmission shaft, a cam body at the end of the shaft, and a convex body on the cam body. The rolling body is fixedly connected or integrally formed with the transmission shaft. During the rotation of the transmission shaft, the convex body on the cam body at the end of the shaft and the impact rod in the impact device form a cam pair, so that the rotation of the rolling body can be realized by the cam mechanism along the impact device. Preset direction shocks. The cam structure is simple, safe and reliable, and easy to implement.

As a preferred solution of the present invention, the transmission device is a gear mechanism. The implementation and transmission principle of the gear mechanism will be described in conjunction with accompanying drawing 9. The gear mechanism includes a transmission shaft, a transmission gear, a driven gear and a convex body on the driven gear. The transmission shaft and the rolling body are fixedly connected or integrally formed. The transmission gear and The transmission shaft is fixedly connected or integrally formed. When working, the rolling body drives the transmission shaft and the transmission gear at the bottom end of the transmission shaft to rotate, and the driven gear meshes with the transmission gear to generate rotation. The convex body on the driven gear and the impact rod in the impact device form a cam pair to realize the direction of the impact teeth. Impact direction impact. Gear transmission is stable and easy to implement.

As a preferred solution of the present invention, the rolling elements include roller cones, rollers, and rollers.

As a preferred solution of the present invention, the impact rod is provided with an elastic element, the elastic element can be a spring, a disc spring, rubber, etc., and the elastic element is used to realize the rebound of the impact rod after impact. For the impact unit, after the impact teeth complete an impact, they need to return in time, otherwise they cannot successfully complete the next impact. The elasticity provided on the impact rod is easy to realize, and the structure is simple and reliable.

As a preferred solution of the present invention, the impact teeth are arranged in front or behind the cutting teeth. Obviously, it is easy for researchers in the field to think that the impact teeth and cutting teeth are designed on the same track.

As a preferred solution of the present invention, the composite drill bit has at least one tooth arrangement blank area around the center of the drill bit, and the impacting direction of the impact teeth is the radial direction of the drill bit.

The present invention at least includes the following beneficial effects:

1. The impact unit realizes the impact by relying on the rotation of the drill bit, and does not need to be equipped with impactor tools, which saves costs. At the same time, the rolling body in the impact unit is in contact with the rock at the bottom of the well, which can further reduce the working torque during the drilling process of the drill bit;

2. The impact action of the impact unit further forms the impact crushing or pre-damage on the rock. The cutting teeth consume less energy when crushing these weakened strata. While improving the rock breaking efficiency, it reduces the cutting teeth chipping probability of failure;

3. When the transmission device in the impact unit of the present invention adopts a cam mechanism or a gear transmission mechanism, the structure is simple, safe and reliable, and easy to implement.

4. In the scheme where the rolling body is arranged at the gage of the blade, the circumferential support point of the composite drill bit can be increased, the circumferential vibration during the drilling process can be reduced, and the sustainable drilling capability of the drill bit can be further improved.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore do not It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is a schematic structural diagram of a compound drill bit provided by the first embodiment of the present invention.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is a schematic structural view of the percussion unit on the compound drill bit provided by the first embodiment of the present invention.

FIG. 4 is a partial sectional view of FIG. 2 .

Fig. 5 is a structural schematic diagram in which the rolling elements in the impact unit provided by the first embodiment of the present invention are rollers.

Fig. 6 is a schematic diagram of the meaning of the distance L between the rolling element and the gage line of the blade in the impact unit provided by the first embodiment of the present invention.

Fig. 7 is a schematic structural view of the impact teeth in the impact unit provided by the first embodiment of the present invention as wedge teeth.

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

Fig. 9 is a schematic diagram of the principle of impacting teeth and cutting teeth with the same track design to break rocks.

Fig. 10 is a schematic structural view of the compound drill bit provided by the third embodiment of the present invention.

FIG. 11 is a top view of FIG. 10 .

Fig. 12 is a schematic diagram of the well bottom covering in Fig. 10 .

Icons: 1-compound drill; 2-drill body; 3-blade; 30-rolling groove; 31-cutting teeth; 32-impact hole; 4-blade gauge; 40-blade gauge line; 5-support Body; 51-support body matrix; 52-support body matching body; 53-transmission hole; 6-impact unit; 61-rolling body; 62-transmission device; 63-impact device; ;622-convex body; 623-cam body; 631-impact tooth; 632-impact rod; Gear; 92-driven gear; 10-tooth palm; 11-cone wheel; 111-tooth.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is some embodiments of the present invention, but not all of them. Based on the implementation manners in the present invention, all other implementation manners obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. Accordingly, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. Based on the implementation manners in the present invention, all other implementation manners obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

First embodiment:

Please refer to FIG. 1-FIG. 8 , the embodiment of the present invention provides a composite drill bit 1 .

A composite drill bit 1 includes a drill body 2, a blade 3, a tooth palm 10, and a cone 11. The blade 3 is fixedly connected to the drill body 2 or integrally formed. The blade 3 is provided with cutting teeth 31. The cone 11 and the The tooth palm 10 forms a rotational connection through a shaft, the tooth 111 is arranged on the cone 11 , and the impact unit 6 is arranged on the compound drill bit 1 through the supporting body 5 .

Please refer to Fig. 3-Fig. 6, the impact unit 6 is made up of rolling body 61, transmission device 62 and impact device 63; The distance between the rolling outer contour 610 and the blade gauge line 40 in the radial direction is L, and its range is -d/4≤L≤d/4, where d is the cutting tooth diameter; the impact device 63 consists of an impact rod 632 and At least one impact tooth 631 is formed; the rotation of the rolling element 61 can realize the impact of the impact device 63 along the impact direction through the transmission device 62 . In order to facilitate the installation of the impact unit 6 , the support body 5 is set in a split type (one part is the support body base 51 , and the other part is the support body matching body 52 ), please refer to FIG. 4 .

In the embodiment of the present invention, the rolling body 61 of the impact unit 6 is a cone structure. During the rock breaking process, the cone contacts with the rock to generate a rotational moment and rotates. The rolling body 61 can also be a roller (see FIG. 5 ) or a roller.

Please refer to FIG. 3 and FIG. 4 , the transmission device 62 is a cam mechanism, and the cam mechanism includes a transmission shaft 621 , a cam body 623 at the end of the shaft, and a convex body 622 on the cam body 623 . The rolling element 61 is fixedly connected or integrally formed with the transmission shaft 621, and the transmission shaft 621 is arranged in the transmission hole 53 of the supporting body 5. During the rotation, the convex body 622 on the cam body 623 at the shaft end forms a shape with the impact rod 632 in the impact device 63. The cam pair, and the impact rod 632 is arranged in the impact hole 32 of the blade, so that the rotation of the rolling element 61 can realize the impact of the impact device 63 along the preset direction through the cam mechanism. The connection methods between the cam body 623 and the transmission shaft 621 include rigid fit, screw connection, welding, integral molding and the like. The cam structure is simple, safe and reliable, and easy to implement. For the impact unit, after the impact tooth 631 completes an impact, it needs to return, otherwise it cannot complete the next impact (stroke). The element 8 can be a spring 81 (see FIG. 3 ), a disc spring 82 (see FIG. 8 ), rubber, etc. The elastic element 8 is used to realize the rebound of the impact device 63 after the impact is completed. The elastic element 8 provided on the impact rod 632 in this embodiment is easy to realize, and has a simple and reliable structure.

The impact teeth 631 can be bevel teeth (see Figures 1-4, Figure 8, Figure 10 and Figure 11), wedge teeth (see Figure 7), spoon teeth, spherical teeth, etc. Materials include artificial polycrystalline diamond, natural diamond, cemented carbide, ceramics, cubic boron nitride, etc. The connection of the impact tooth 631 and the impact rod 632 can be threaded connection, interference fit, welding, or integral molding, etc. In this example, the integral molding is used.

Researchers in the field can easily imagine that the impact tooth 631 can be arranged in front of or behind the cutting tooth 31 , or can be arranged at the same time. In the solution where the impact teeth 631 are arranged in front of the cutting teeth 31 , there is a more optimal solution, that is, the impact teeth 631 and the cutting teeth 31 are designed on the same track. Please refer to Fig. 8. When the impact tooth 631 and the cutting tooth 31 are designed on the same track, the two have approximately the same positioning radius in the bottom-hole coverage diagram. cracks, and the cutting teeth 31 following the same orbital rotation break the damaged stratum with less energy consumption.

The beneficial effect of the PDC drill provided by the embodiment of the present invention is:

1. The impact unit 6 realizes the impact by relying on the rotation of the drill bit, and does not need to be equipped with impactor tools, which saves costs. At the same time, the impact unit 6 is set at the blade gage 4, and the rolling element 61 on it is in contact with the well wall, increasing the circumferential support point of the composite drill bit and further reducing the working torque during the drilling process of the drill bit;

2. The impact action of the impact unit 6 can form impact crushing or pre-damage to the rock. The cutting teeth 31 of the drill bit consume less energy when crushing these weakened formations. While improving the rock breaking efficiency, the cutting teeth are reduced 31 Probability of chipped tooth failure;

3. The transmission device 62 in the impact unit 6 of the present invention is a cam mechanism, which is simple in structure, safe and reliable, and easy to implement.

Second embodiment:

The embodiment of the present invention provides a compound drill bit, the structure of this compound drill bit 1 is basically the same as that of the compound drill bit 1 in the first embodiment, the difference is: please refer to Fig. 9, in this embodiment, the transmission device 62 is a gear The mechanism includes a transmission shaft 621, a transmission gear 91, a driven gear 92, and a convex body 622 on the driven gear 92. The transmission shaft 621 is fixedly connected or integrally formed with the rolling element 61, and the transmission gear 91 is fixedly connected or integrally formed with the transmission shaft 621. forming. During work, 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 meshes with the transmission gear 91 and rotates, the convex body 622 on the driven gear 92 and the impact in the impact device 63 The rod 632 forms a cam pair to realize the impact of the impact tooth 631 towards the impact direction. Gear transmission is stable and easy to implement.

Third embodiment:

Please refer to Fig. 10-Fig. 12, a kind of composite drill bit 1, comprises drill body 2, blade 3, tooth palm 10, cone 11, blade 3 is fixedly connected with drill body 2 or integrally formed, and blade 3 is provided with The cutting teeth 31, the cone 11 and the tooth palm form a rotational connection through the shaft, the cone 11 is provided with teeth 111, the composite drill bit 1 has at least one tooth arrangement blank area 7 around the center of the drill bit, and the blade 3 is provided with an impact Unit 6.

Impact unit 6 is made of rolling element 61, transmission device 62 and impact device 63; Rolling element 61 can rotate around its own axis and is arranged in the rolling groove 30 of blade 3; Impact device 63 is made of impact rod 632 and at least one impact tooth 631 Composition; the rotation of the rolling body 61 can realize the impact of the impact device 63 toward the radial direction of the compound drill bit 1 through the transmission device 62 .

In the above-mentioned scheme, the blank area 7 of the tooth arrangement is at the center of the drill bit, and a corresponding raised rock ridge 71 will be formed at the bottom of the well during the bottom-hole work, and the original rock constraints around the rock ridge 71 are released, so the rock ridge 71 The strength of itself is significantly reduced, which is equivalent to an isolated "wall" or "column". In fact, the direction of these raised rock ridges 71 is consistent with the direction of drilling or the axis of the drill bit. When the impact direction of the impact teeth 631 is towards the radial direction of the drill bit, the impact teeth 631 will impact these isolated rock ridges 71 at a certain angle. The crushing energy consumption will be greatly reduced, and the crushing method tends to be more volumetric crushing, and the rock-breaking efficiency is further improved.

Claims (9)

1. A composite drill bit, comprising a drill body, a blade, a tooth palm and a cone, the blade is fixedly connected with the drill body or integrally formed, the blade is provided with cutting teeth, and the cone and the The palm forms a rotational connection through a shaft, and it is characterized in that an impact unit is arranged on the composite drill bit, and the impact unit is composed of a rolling body, a transmission device and an impact device; the rolling body can rotate around its own axis; the The impact device is composed of an impact rod and at least one impact tooth; the rotation of the rolling body can realize the impact of the impact device through the transmission device; the impact unit is arranged on the blade. 2 . The compound drill according to claim 1 , wherein a supporting body is arranged on the drill body, and the impact unit is arranged on the supporting body. 3 . 3. A compound drill bit according to claim 1, characterized in that, the transmission device is a cam mechanism. 4. A compound drill bit according to claim 1, characterized in that, the transmission device is a gear mechanism. 5. A composite drill according to claim 1, wherein the rolling elements comprise cones, rollers or rollers. 6. A compound drill bit according to claim 1, characterized in that, 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 to realize the impact The rebound of the device after impact. 7. The composite drill bit according to claim 1, wherein the impact teeth are arranged in front or behind the cutting teeth. 8 . The composite drill bit according to claim 1 , characterized in that, the drill bit has at least one tooth arrangement blank area around the center of the drill bit; the impact direction of the impact teeth is the radial direction of the drill bit. 9. A compound drill bit according to claim 1, wherein the impact teeth include bevel teeth, wedge teeth, spoon teeth or spherical teeth; the material of the impact teeth includes artificial polycrystalline diamond , Natural diamond, cemented carbide, ceramics or cubic boron nitride.

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