CN115538946A - Roller cone type composite PDC drill bit - Google Patents

Abstract

The invention discloses a cone type composite PDC drill bit, which comprises a bit body, fixed blades extending from the bit body and cones arranged on the fixed blades or bit legs, wherein cutting teeth are embedded on the fixed blades and the cones, and a mandrel of each cone is rotationally connected with a supporting blade or bit leg of the mandrel. The method is characterized in that: the oil storage assembly is arranged in the cone or the mandrel and sealed on the mandrel through the gland, and the gland is also provided with a one-way valve for controlling the one-way flow of the drilling fluid. The invention has the beneficial effects that: on one hand, under the fluctuation action of the pressure of the drilling fluid at the bottom of the well, the oil storage assembly is always maintained in a high-pressure state through the one-way valve, so that the bearing system can be lubricated more fully; on the other hand, the structure of a fixed blade or a cone leg for supporting the cone is simplified, the difficulty of machining and manufacturing processes is reduced, the structural strength is improved, and the assembly is simple and convenient.

Description

A kind of roller cone type composite PDC drill bit

technical field

The invention belongs to the technical equipment fields of petroleum and natural gas drilling engineering, mining engineering, building foundation engineering construction, geological drilling, tunnel engineering, hydrology, shield tunneling and non-excavation, and in particular relates to a drilling bit.

technical background

PDC bit is the most widely used rock-breaking tool in drilling engineering to break rock and form a wellbore. PDC drill bits rely on high hardness, high wear resistance, and self-sharpening polycrystalline diamond composite sheets to shear and break rocks. Due to their high mechanical penetration rate, long life and good drilling safety in soft to medium hard formations, they are widely used in drilling engineering. are widely used in. The fixed cutter bits represented by PDC bits usually have several blades, and multiple cutting elements are arranged on the blades along the radial direction of the drill (for PDC bits, the cutting elements are mainly polycrystalline diamond composite sheets, referred to as composite sheets or PDC teeth).

In the Chinese patent "A Composite Drill Bit for Rock Breaking by Cutting" (Patent No.: 201010229371.9) submitted by Southwest Petroleum University, PDC teeth are set as the main cutting element for the first time at a position with a large offset angle (offset angle a 20 ° ≤ | a | ≤ 90 °) on the runner (that is, the called toothed wheel in this application). The different motion patterns of the two sets of cutting units form a cross-netted well bottom. This cross-cutting rock-breaking method greatly improves the drilling speed of the drill bit. Another Chinese patent "A Composite Cutting Diamond Bit" (Patent No.: 201710819577.9) submitted by Southwest Petroleum University sets the cones in a fixed blade or in a channel groove between fixed blades to form a double support structure The cone type compound PDC bit. While increasing the stability of the roller cone bit, it also retains the cutting characteristics of the PDC bit.

However, in the prior art including the above-mentioned patented technology, the oil storage assembly is arranged on the fixed blade or tooth palm, the structure and processing technology are complicated, and the manufacture is difficult; the hole for placing the oil storage assembly weakens the blade or tooth. The structural strength of the palm will lead to a reduction in the overall safety of the drill. At the same time, in the prior art, pressure transmission holes are provided on the gland, and the lubricating grease in the oil storage assembly is squeezed into the bearing system to realize lubrication under the action of drilling fluid pressure. However, there are always pressure fluctuations in the drilling fluid, which will cause a "suction" effect on the oil storage assembly, so that the lubricating grease cannot be continuously supplied, and the lubrication effect on the bearing system is also greatly reduced.

Contents of the invention

The purpose of the present invention is to: aim at the deficiency that the composite drill bit with roller cone structure exists, propose a kind of roller cone type composite PDC drill bit of new structure, to simplify the drill bit structure, reduce its processing difficulty, and improve the structural strength and bearing lubrication of the drill bit Effect.

The purpose of the present invention is achieved through the following technical solutions:

A gear-cone composite PDC drill bit, comprising a drill body, a fixed blade extending from the drill body, and a gear set on the fixed blade or tooth palm, and cutting teeth are fixed on the fixed blade and the gear , the mandrel of the cone and its supporting blade or tooth palm form a rotational connection, and an oil storage assembly is arranged inside the cone or mandrel, which is sealed on the mandrel by a gland, and the gland is also provided with The one-way valve, under the fluctuation of the drilling fluid pressure at the bottom of the well, the oil storage assembly is always maintained at a high pressure state through the one-way valve.

Preferably, the mandrel is a double support structure, and the front and rear support blades are respectively connected in rotation with the front support blade and the rear support blade, or a double support rotation connection is formed on the same blade, and an oil storage assembly is arranged inside the cone , which is sealed on the mandrel by a gland, and a one-way valve is also arranged on the gland.

In the above solution, the mandrel adopts a double support structure, which can make full use of the spatial structure of the drill bit reasonably, and improve the rigidity and rotation accuracy of the support body of the drill bit.

Preferably, the cone is fixedly connected to the mandrel through a flat key or a spline.

In the above solution, the connection between the flat key and the spline has high reliability, and the assembly and processing are simple.

Preferably, a hole is provided inside the mandrel, through which the lubricating grease is delivered to the mandrel and the cone, and the rotating pair at the connection position between the mandrel and the blade or tooth palm.

In the above solution, the lubricating grease can quickly flow to the surface of the rotating pair, the flowing path is short, the loss along the way is small, and the lubrication efficiency is high.

Preferably, a radial bearing or a thrust bearing is provided at the connection between the mandrel and the fixed blade or tooth palm.

In the above solution, when the rotation of the cone drives the rotation of the mandrel, the bearing can provide better rotation stability, higher rotation accuracy, and has the advantages of good wear resistance.

Preferably, a sealing ring is provided between the mandrel and the fixed blade or tooth palm, and the rotating pair at the connection between the mandrel and the cone.

In the above solution, the sealing ring can effectively block external abrasive particles from entering the rotating pair, reducing wear and tear.

The technical invention aims to provide a high-efficiency lubrication, simple structure and good stability of the cone-type composite PDC drill bit structure, so the existing cone-PDC composite drill bits or disc cutter composite PDC drill bits can use the provided by the present invention Technical solutions.

The beneficial effects achieved by the patent of the present invention include:

1. Under the fluctuation of drilling fluid pressure at the bottom of the well, the oil storage assembly is always maintained at a high pressure state through the check valve, and the grease can be continuously squeezed into the bearing system, thereby greatly improving the bearing system. Lubricating effect.

2. The oil storage assembly is set inside the cone, which simplifies the structure of the fixed blade or tooth palm, and reduces the difficulty of manufacturing process.

3. Compared with the conventional roller cone-PDC composite drill bit oil storage assembly arranged inside the tooth palm, the technical solution of the present invention improves the structural strength and reliability of the drill bit (especially the fixed blade or tooth palm).

4. The channel path through which the grease passes is shorter than the grease circulation path of the conventional cone-PDC composite drill bit, and the loss along the flow path is small, which improves the lubrication ability and effect.

Description of drawings

The present invention will be described by way of specific embodiment and with reference to accompanying drawing, wherein:

Fig. 1 is the front view of embodiment one among the present invention;

Fig. 2 is the top view of embodiment one among the present invention;

Fig. 3 is the sectional view of the cone section of Embodiment 1 in the present invention;

Fig. 4 is the top view of embodiment two among the present invention;

Fig. 5 is the sectional view of the cone section of the second embodiment of the present invention;

Fig. 6 is the top view of embodiment three among the present invention;

Fig. 7 is the sectional view of the cone section of embodiment three in the present invention;

Figure 8 is a top view of Embodiment 4 of the present invention;

Fig. 9 is the sectional view of the cone section of the fourth embodiment of the present invention;

Fig. 10 is the sectional view of the cone section of the fifth embodiment of the present invention;

Fig. 11 is the sectional view of the cone section of the sixth embodiment of the present invention;

Reference signs: 1—drill bit body; 11—water eye; 2—fixed blade; 21—front supporting blade; 22—rear supporting blade; 3—tooth palm; 4—cone wheel; 5—cutting tooth; 51 —composite tooth; 52—tungsten carbide tooth; 6—mandrel; 61—hole; 62—ball channel; 7—oil storage assembly; 81—flat key; 82—spline; 83—ball; 84—seal 841—second sealing ring; 842—third sealing ring; 85—circlip; 86—gland; 861—one-way valve; 91—radial bearing; 92—thrust bushing.

detailed description

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar alternative features. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

The present invention will be further described below in combination with specific embodiments and accompanying drawings.

Embodiment one:

As shown in Fig. 1, Fig. 2 and Fig. 3, a gear-cone composite PDC bit includes a bit body 1, a water eye 11, a fixed blade 2 and a tooth palm 3 extending from the bit body 1, and is arranged on the tooth palm 3 The toothed wheel 4 on the top is inlaid with inherent composite teeth 51 on the fixed blade 2 and the toothed wheel 4. The cutting teeth 5 are composite teeth 51 or hard alloy teeth 52. The toothed wheel 4 can be positioned relative to its own mandrel 6. Do rotary motion, wherein the toothed wheel 4 is a disc cutter structure. The mandrel 6 is axially locked and fixed on the tooth palm 3 through the ball 83 , and the cone 4 is fixedly connected with the mandrel 6 through the flat key 81 . An oil storage assembly 7 is arranged inside the cone 4 for storing lubricating oil or grease, which can be delivered to the rotating pair through the hole 61 to realize lubrication. A gland 86 is also arranged on the cone 4 to seal the oil storage assembly 7 inside the cone 4 through a snap ring 85 , and a one-way valve 861 is arranged on the gland 86 . The balls 83 are installed between the revolving pair via the ball channel 62, and a sealing ring 84 is also provided between the cone 4 and the tooth palm 3 to realize sealing.

In the traditional technology, the oil storage assembly is arranged inside the tooth palm, and the channels for conveying grease are generally elongated holes, and are arranged alternately with the ball channels. The palm is a special-shaped piece with a complex structure, and it bears a huge working load in drilling construction. Therefore, the traditional tooth palm is not only difficult to process, but also is a vulnerable part of the composite drill bit, and accidents of broken tooth palms often occur. In addition, in the prior art, pressure transmission holes are provided on the gland, and the lubricating grease in the oil storage assembly is squeezed into the bearing system under the action of drilling fluid pressure to achieve lubrication. However, there are always pressure fluctuations in the drilling fluid, which will cause a "suction" effect on the oil storage assembly, so that the lubricating grease cannot be continuously supplied, and the lubrication effect on the bearing system is also greatly reduced.

In this technical solution, the oil storage assembly 7 is directly installed inside the cone 4, and a check valve 861 is provided on the gland 86. When the lubricating grease is lost, the oil storage assembly 7 will The lubricating grease in 7 is directly transported to the rotating pair of the mandrel 6 through the hole 61 to realize lubrication.

In this technical solution, under the fluctuation of the drilling fluid pressure at the bottom of the well, the oil storage assembly is always maintained at a high pressure state through the check valve, and the lubricating grease can be continuously squeezed into the bearing system, thereby greatly improving the oil resistance. Lubrication effect of the bearing system. At the same time, the simplification of the palm structure can significantly reduce the difficulty of manufacturing and improve the structural strength.

Embodiment two:

As shown in Fig. 4 and Fig. 5, this embodiment is basically the same as "Embodiment 1". The difference lies in that the mandrel 6 and the tooth palm 3 are of an integrated structure, and the cemented carbide teeth 52 are inlaid on the cone 4; the cone 4 can rotate relative to the mandrel 6, and no flat key is arranged between them.

This embodiment is an innovative and optimized application based on the conventional roller cone-PDC composite drill bit. Its purpose is to simplify the structure of the palm 3, improve the structural strength, reduce the difficulty of the manufacturing process, and improve the lubrication effect of the drill bit.

Embodiment three:

As shown in Fig. 6 and Fig. 7, this embodiment is basically the same as "Embodiment 1". The difference is that the mandrel 6 is supported by the front support blade 21 and the rear support blade 22, which is a double support structure; a radial bearing 91 is also arranged between the front support blade 21 and the mandrel 6; A sealing ring 84 is arranged between the rear supporting blade 22 and the cone 4, a second sealing ring 841 is arranged between the forward supporting blade 21 and the mandrel 6, and a sealing ring 841 is arranged between the gland 86 and the forward supporting blade 21. A third sealing ring 842 is provided.

This embodiment is an innovative and optimized application based on the conventional double-support disc cutter compound PDC drill bit. The mandrel is supported by the front and rear support blades, which has better stability. The centering of the mandrel and the cone is good. The strength of the mandrel is less weakened, it can bear larger loads and has the characteristics of high rotation precision.

Embodiment four:

As shown in Fig. 8 and Fig. 9, this embodiment is basically the same as "Embodiment 3". The difference is that: the mandrel 6 is installed longitudinally on the fixed blade 2, and the front and rear support loads are all borne by the fixed blade 2; the gear 4 is inlaid with hard alloy teeth 52; A sealing ring 84 and a second sealing ring 841 are arranged between them, and a third sealing ring 842 is arranged between the gland 86 and the fixed blade 2 .

This embodiment is an innovative and optimized application based on the conventional double-supported roller cone compound PDC bit. The two ends of the mandrel are supported by the same blade, which has better stability and can also make the mandrel and the cone have a good alignment. Neutral, capable of bearing greater loads and high rotational precision.

Embodiment five:

As shown in FIG. 10 , this embodiment is basically the same as "Embodiment 3". The difference is that a thrust bearing 92 is also provided between the spindle 6 and the rear supporting blade 22 .

In this embodiment, setting the thrust bearing 92 can better realize the support accuracy, have higher wear resistance, and can further guarantee the rotation accuracy and service life.

Embodiment six:

As shown in Figure 11, this embodiment is basically the same as "Embodiment 5". The difference is that the spline 82 is connected between the mandrel 6 and the cone 4 .

In this embodiment, the cone and the mandrel are connected by splines, which has better transmission and bearing capacity.

Claims (6)

1. A roller cone type composite PDC drill bit, comprising a drill body, a fixed blade extending from the drill body, and a roller cone arranged on the fixed blade or tooth palm, all inlaid and fixed on the fixed blade and the cone Cutting teeth, the spindle of the cone and its supporting blade or tooth palm form a rotational connection. It is characterized in that: an oil storage assembly is arranged inside the cone or spindle, which is sealed on the spindle through a gland. A one-way valve is also arranged on the gland. 2. A cone-type composite PDC drill bit according to claim 1, characterized in that: the mandrel is a double support structure, and the front and rear respectively form a rotational connection with the front support blade and the rear support blade, or in the same The knife wing forms a double-supported rotary connection, and an oil storage assembly is arranged inside the cone, which is sealed on the mandrel through a gland, and a check valve is also arranged on the gland. 3. A roller cone type composite PDC drill bit according to claim 1, characterized in that: the roller cone is fixedly connected to the mandrel through a flat key or a spline. 4. A cone-type composite PDC drill bit according to claim 1, characterized in that: a hole is arranged inside the mandrel, and the lubricating grease is transported to the mandrel and the cone, and the mandrel is connected with the blade or tooth palm through the hole. position of the revolving pair. 5. A roller cone type composite PDC drill bit according to claim 1, characterized in that: a radial bearing or a thrust bearing is arranged at the joint between the mandrel and the fixed blade or tooth palm. 6. A cone-type composite PDC drill bit according to claim 1, characterized in that: a sealing ring is arranged between the mandrel and the fixed blade or tooth palm, and the rotating pair at the joint between the mandrel and the cone .

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