CN110242221B

CN110242221B - PDC drill bit with wide application range

Info

Publication number: CN110242221B
Application number: CN201910586570.6A
Authority: CN
Inventors: 林正富
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-07-01
Filing date: 2019-07-01
Publication date: 2022-02-18
Anticipated expiration: 2039-07-01
Also published as: CN110242221A

Abstract

The invention provides a PDC drill bit with a wide application range, which comprises a drill bit body, blades and first cutting teeth, wherein the first cutting teeth are polycrystalline diamond composite sheets, the blades are fixedly connected with the drill bit body or integrally formed, the first cutting teeth are arranged on the blades, grooves are formed in the first cutting teeth, one ends of the grooves penetrate through the front working face of the first cutting teeth, filling bodies are arranged in the grooves, the wear resistance of the filling bodies is weaker than that of a diamond layer, and the filling bodies are fixedly connected with the side walls of the grooves. The PDC drill bit provided by the invention has the advantages that the groove and the filling body are arranged, so that the PDC drill bit can obtain higher drilling speed in a soft stratum and has stronger penetration capability in a hard stratum.

Description

PDC drill bit with wide application range

Technical Field

The invention relates to the technical fields of oil and gas drilling engineering, mine engineering, geological drilling, tunnel engineering and the like, in particular to a PDC drill bit with a wide application range.

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 cuts rock through the PDC teeth to break the rock, can obtain ideal drilling speed in soft to medium hard strata, and is widely applied to oil and gas drilling.

With the development of shallow oil-gas resources being almost exhausted, the emphasis of oil-gas exploration and development gradually shifts to deep layer and deep sea. 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, as the depth of the stratum increases, the hard-plastic stratum is more and more, the cutting teeth cannot effectively bite into the stratum, the drilling efficiency is low, vibration is easy to occur, and then the rapid failure of the cutting teeth is caused.

Particularly, the reason for restricting the PDC drill bit from efficiently drilling in a hard formation is that after the drill bit is worn, the contact area between the cutting teeth and the rock is increased, the drilling specific pressure of the cutting teeth is sharply reduced, the drilling efficiency is very low, even the bit is pulled out, the drilling cost is increased, and the drilling period is prolonged.

Disclosure of Invention

The invention provides a PDC drill bit with wide application range, aiming at solving the problems in the prior art that: soft to medium hard formations drill at fast rates, while in hard formations the PDC bit has a reduced ability to bite into the rock, which causes a problem of low rates of penetration.

The invention is realized by the following steps:

the utility model provides a wide application scope's PDC drill bit, includes drill bit body, wing and first cutting tooth, and first cutting tooth is polycrystalline diamond compact piece, and the wing is fixed continuous or integrated into one piece with the drill bit body, and on the wing was located to first cutting tooth, be equipped with the recess on the first cutting tooth, recess one end link up to the preceding working face of first cutting tooth, is equipped with the obturator in the recess, and the wearability of obturator is less than the wearability on diamond layer, and the obturator links to each other with the lateral wall of recess is fixed.

The PDC drill bit provided by the invention is provided with teeth with grooves, and the grooves are internally provided with filling bodies with the wear resistance weaker than that of the diamond layer. When drilling in soft formations, the filler body is used to participate in cutting the rock together with the diamond layer, so that a higher rate of penetration can be obtained. During drilling in hard formations, the filler body wears faster than the diamond layer due to its relatively weak wear resistance, so that the filler body gradually wears away and the groove is formed again in the first cutting tooth. The formation of the groove enables the cutting edge of the first cutting tooth to have higher drilling specific pressure, the biting capacity can be guaranteed, and meanwhile, a larger rock ridge can be formed. After the rock ridge is formed, the rock ridge is subjected to larger stress, and supporting rock bodies are lacked on two sides, so that the rock ridge is easy to damage, and the drilling speed is further improved. Therefore, the PDC drill bit provided by the invention can adapt to drilling of soft formations and hard formations. Yet another unexpected effect of the present invention is: when the hard stratum is drilled, after the filling body is abraded, a rock ridge is formed at the bottom of the well, the lateral contact surface of the cutting tooth and the rock at the bottom of the well is increased, and transverse vibration is weakened.

In a preferred embodiment of the invention, the filler body is a structure made of tungsten carbide and/or cemented carbide.

Further, as a preferable mode, the filling body is connected to the side wall of the groove by high-temperature high-pressure bonding.

In a preferred embodiment of the invention, the other end of the groove penetrates the side face of the first cutting tooth, and the cross-sectional dimension of the groove is gradually reduced in a direction from the front working face of the PDC tooth to the rear working face of the PDC tooth. The connection between the PDC teeth and the blades is often achieved by: one end of the side surface of the PDC tooth, which is close to the rear working surface, is connected with the blade through bonding. Therefore, through the structure provided by the invention, the rear working surface and the nearby side surface of the PDC tooth can keep a complete cylinder shape, thereby being beneficial to ensuring the bonding stability between the PDC tooth and the blade.

In a preferred embodiment of the invention, the other end of the recess extends through to the rear face of the first cutting tooth. Through this kind of structure, be favorable to reducing the processing degree of difficulty of recess.

In a preferred embodiment of the invention, there is further included a second cutting tooth provided on the blade, the relative position between the first cutting tooth and the second cutting tooth on the same blade being configured such that: the second cutting tooth is disposed rearward of the first cutting tooth in a circumferential direction formed by rotation of the drill bit. Through the structure, the tooth distribution density of the drill bit is improved, and the abrasion of the drill bit is favorably slowed down.

In a preferred embodiment of the present invention, the distance between the second cutter and the axis of the PDC bit is greater than one-half the radius of the PDC bit.

In a preferred embodiment of the invention, the position of the second cutter on the PDC bit is configured to: for each second cutting tooth, the at least one second cutting tooth is co-orbital with the at least one first cutting tooth. The same-track arrangement means that in a bottom hole tooth distribution coverage map, two cutting teeth arranged on the same track have the same positioning radius, namely, under ideal drilling conditions, the motion trails of characteristic points of the two cutting teeth are the same.

What needs to be specifically mentioned is that: the shaft bottom tooth distribution coverage map is formed by that in any axial plane passing through the central line of a 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. The bottom hole tooth distribution coverage map directly reflects the important parameters of the positioning radius, the positioning height and the like of the cutting tooth.

Through the structure, after the first cutting teeth cut the bottom hole to form the rock ridge, the second cutting teeth are used for crushing the rock ridge formed by the first cutting teeth at the front position of the same track, and the rock ridge is subjected to larger stress, and supporting materials are lacked on two sides, so that the volume crushing is easily generated, and the drilling speed is further improved.

In a preferred embodiment of the invention, the second cutting tooth is a conical tooth or a hatchet-type tooth. Through the structure, the shape of the second cutting tooth can be better matched with the shape of the rock ridge, so that the cutting effect is improved.

In a preferred embodiment of the invention, the height of the edge of the second cutting tooth is less than or equal to the height of the edge of the first cutting tooth. Through the structure, the second cutting tooth has stronger pertinence to the rock ridge formed by the front first cutting tooth in the same track.

In preferred embodiments of the invention, the cross-section of the groove comprises a cone, an ellipse or a rectangle.

The invention at least comprises the following beneficial effects:

1. through the structural design of the first cutting teeth, the PDC drill bit can be well suitable for the drilling work of soft strata, and can also obtain higher drilling speed in hard strata;

2. the second cutting teeth are arranged, so that the overall abrasion speed of the drill bit can be delayed, and the service life of the drill bit can be prolonged;

3. in the drilling of a hard formation, a larger rock ridge can be formed through the first cutting teeth, and meanwhile, the rock ridge formed by the front first cutting teeth on the same track is damaged through the second cutting teeth, so that an independent rock ridge is damaged, the volume is more easily crushed, and the mechanical drilling speed is increased;

4. when drilling in a hard stratum, after the filling body is worn, a rock ridge is formed at the bottom of a well, so that the lateral contact surface of the cutting teeth and rocks at the bottom of the well is increased, and the transverse vibration is weakened;

5. compared with the prior art, the structure of the invention still has higher specific drilling pressure and strong continuous and efficient drilling capability after the drill bit is worn.

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 PDC drill bit according to a first embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a PDC drill bit according to a first embodiment of the present invention from another view angle.

FIG. 3 is a schematic representation of a first cutter of a PDC bit according to a first embodiment of the present invention.

FIG. 4 is a schematic diagram of a first embodiment of the present invention showing a PDC bit having a worn pack of first cutting teeth.

FIG. 5 is a bottom hole tooth placement overlay of a PDC bit provided in accordance with a first embodiment of the present invention with the packing unworn.

FIG. 6 is a bottom hole tooth placement overlay of a PDC bit provided in accordance with a first embodiment of the present invention after pack wear.

FIG. 7 is a schematic illustration of a PDC bit provided in accordance with a first embodiment of the present invention cutting the bottom hole to form a ridge after the pack has worn away.

FIG. 8 is a schematic representation of a first cutter on a PDC bit according to a second embodiment of the present invention.

FIG. 9 is a schematic diagram of a PDC bit according to a third embodiment of the present invention.

FIG. 10 is a schematic diagram of a PDC bit having worn fillers according to a fourth embodiment of the present invention.

FIG. 11 is a bottom hole tooth placement overlay of a PDC bit having a fourth embodiment of the present invention after pack wear.

FIG. 12 is a bottom hole tooth placement overlay of a PDC bit provided by a fifth embodiment of the present invention after pack wear.

Fig. 13 is a schematic structural view of an axe-type tooth provided in an embodiment of the present invention.

Icon: 1-PDC drill bits; 2-ridge of rock; 11-a bit body; 12-a blade; 13-first cutting teeth; 14-a second cutting tooth; 131-a groove; 132-a filler; 133-front working face; 134-rear working face.

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. 1-7, an embodiment of the present invention provides a PDC drill bit 1 with a wide application range.

Referring to fig. 1 and 2, the drill includes a drill body 11, a blade 12 and a first cutting tooth 13, wherein the first cutting tooth 13 is a polycrystalline diamond compact, the blade 12 and the drill body 11 are integrally formed, and a tooth slot for mounting the first cutting tooth 13 is formed on the blade 12.

Referring to fig. 3 and 4, the first cutting tooth 13 is provided with a concave groove 131, and one end of the concave groove 131 penetrates through the front working surface 133 of the first cutting tooth 13. The front working surface 133 refers to a diamond layer surface of the polycrystalline diamond compact, and during the drilling process of the PDC drill bit 1, the front working surface 133 is used for cutting rock, and the front working surface 133 and the rear working surface 134 are arranged opposite to each other. The other end of the recess 131 penetrates to the side of the first cutting tooth 13. Further, the cross-sectional shape of the recess 131 may be provided in a tapered, circular, oval or rectangular shape in a direction directed toward the rear working surface 134 along the front working surface 133 of the first cutting tooth 13, in which direction the cross-sectional dimension of the recess 131 is gradually reduced.

The groove 131 is provided with a filler 132, the filler 132 is a structural body made of a material having a lower wear resistance than polycrystalline diamond, and the filler 132 is fixedly connected with the side wall of the groove 131, so that the first cutting tooth 13 is of a cylindrical tooth structure or an elliptical tooth structure as a whole. Further, the filler 132 may be provided as a structure made of cemented carbide or a structure sintered from tungsten carbide powder, so that the filler 132 has an ability to cut the formation in a softer formation.

The PDC drill bit 1 provided by the embodiment of the invention has the beneficial effects that:

referring to the bottom hole tooth arrangement overlay shown in fig. 5, the packing 132 can participate in cutting the formation along with the diamond layer on the first cutting tooth 13 when drilling in soft formations; referring to fig. 6 and 7, when drilling in a hard formation, the first cutting tooth 13 will be worn, and the wear resistance of the material of the filler 132 is low, so that the wear rate of the filler 132 is much greater than that of the diamond layer, so that the filler 132 on the first cutting tooth 13 gradually disappears, the groove 131 is gradually formed, and along with the formation of the groove 131, the cutting edge of the first cutting tooth is sharper, the specific pressure of drilling is high, which is beneficial to enhancing the capability of the PDC drill bit 1 to bite into the formation, and ensures the drilling rate in the hard formation. In addition, through the structure of the groove 131, a larger rock ridge 2 with the sectional area equivalent to that of the groove 131 can be formed at the bottom of the well, the rock ridge 2 is subjected to larger stress, and supporting materials are lacked on two sides of the rock ridge 2, so that the volume crushing of the rock ridge 2 is favorably formed in the subsequent cutting process, and the drilling speed is further ensured. In addition, after the rock ridge is formed at the bottom of the well, the lateral contact surface of the cutting tooth and the rock at the bottom of the well is increased, and the transverse vibration is weakened.

Second embodiment:

the embodiment of the invention provides a PDC drill bit 1 with a wide application range, and the PDC drill bit 1 is different from the PDC drill bit 1 in the first embodiment in that: in the present embodiment, the structure of the first cutting tooth 13 is slightly different from the structure of the first cutting tooth 13 in the first embodiment.

Referring to fig. 8, in the present embodiment, one end of the groove 131 penetrates the front working surface 133 of the first cutting tooth 13, and the other end penetrates the rear working surface 134 of the first cutting tooth 13.

On the basis of the beneficial effects of the PDC drill bit 1 provided in the first embodiment, the PDC drill bit 1 provided in the present embodiment further has the following beneficial effects:

the recesses 131 penetrate the first cutting teeth 13 in the axial direction of the first cutting teeth 13, which contributes to reducing the difficulty of machining the first cutting teeth 13.

The third embodiment:

the present embodiment provides a PDC drill bit 1 having a wide application range, and the PDC drill bit 1 is different from the PDC drill bit 1 of the first embodiment in that: in this embodiment, the blade 12 is further provided with a second cutting tooth 14.

Referring to fig. 9, specifically, the second cutting teeth 14 are disposed in the outer half area of the PDC bit 1, namely: the distance between the second cutting tooth 14 and the axis of the PDC bit 1 is greater than one-half of the radius of the PDC bit 1. The relative position between the first cutting tooth 13 and the second cutting tooth 14 on the same blade is configured such that: the second cutter 14 is disposed behind the first cutter 13 in the circumferential direction formed by the rotation of the drill. The position of the second cutting teeth 14 in the axial and radial direction of the PDC bit 1 is configured such that: for each second cutting tooth 14, it is arranged in the same orbit as the at least one first cutting tooth 13.

In this embodiment, the second cutting tooth 14 has the same structure as the first cutting tooth 13.

the number of the cutting teeth is increased, the abrasion of the external cutting teeth is favorably reduced, and the service life of the cutting teeth in the difficult-to-drill stratum is further favorably prolonged.

The fourth embodiment:

the embodiment of the present invention provides a PDC drill bit 1 with a wide application range, and the PDC drill bit 1 is different from the PDC drill bit 1 in the third embodiment in that: in this embodiment, the second cutting tooth 14 has a different structure.

Referring to fig. 10 and 11, in the present embodiment, the second cutting tooth 14 is configured as a cylindrical tooth or an elliptical tooth, and the difference L between the cutting height of the second cutting tooth 14 and the cutting height of the first cutting tooth is less than or equal to 0mm, that is: the height of the edge of the second cutting tooth 14 is less than or equal to the height of the edge of the first cutting tooth 13. Further, the range of the height difference L is set to-5 mm-0 mm.

On the basis of the advantageous effects of the PDC drill bit 1 in the third embodiment, the PDC drill bit 1 provided in the present embodiment further has the following advantageous effects:

the second cutting teeth 14 and the first cutting teeth 13 are arranged in the same track, the track of the second cutting teeth 14 can be overlapped with the rock ridge 2 generated by the first cutting teeth 13, and then the second cutting teeth can cut the rock ridge 2 to form volume crushing of the rock ridge 2;

the difference in height of the edge of the second cutting teeth 14 is less than 0mm, so that the second cutting teeth 14 cannot be in contact with other rock masses except the rock ridge 2 at the bottom of the well, the second cutting teeth have stronger pertinence to the rock ridge 2, the volume is easy to crush, and the rock breaking efficiency is improved.

Fifth embodiment:

the PDC drill bit 1 provided in the present embodiment has substantially the same structure as the PDC drill bit 1 in the fourth embodiment, and the difference is that: in the present embodiment, the second cutter 14 is a tapered PDC tooth.

Referring to fig. 12, in particular, the second cutting tooth 14 is provided with a tapered portion, and the tapered portion is used for corresponding to the position of the groove 131 of the forward first cutting tooth 13 in the same track.

In other embodiments of the present invention, referring to FIG. 13, the second cutting tooth 14 may also be configured as an axe-type PDC tooth.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The PDC drill bit with the wide application range comprises a drill bit body, blades and first cutting teeth, wherein the first cutting teeth are polycrystalline diamond composite sheets, the blades are fixedly connected with the drill bit body or integrally formed, and the first cutting teeth are arranged on the blades; in soft formations, the filler body is used to participate in cutting rock with the diamond layer; when drilling in a hard stratum, the material wear resistance of the filling body is low, the wear speed of the filling body is far greater than that of the diamond layer, so that the filling body is gradually worn, the groove is formed on the first cutting tooth again, a large ridge with the sectional area equivalent to that of the groove can be formed at the bottom of the well through the groove structure, the ridge is subjected to large stress, and supporting materials are lacked on two sides of the ridge, so that the volume of the ridge is broken in the subsequent cutting process, and the drilling speed is improved; after the rock ridge is formed at the bottom of the well, the lateral contact surface of the cutting tooth and the rock at the bottom of the well is increased, so that the transverse vibration is weakened;

and a second cutting tooth disposed on the blade, the relative position between the first cutting tooth and the second cutting tooth on the same blade being configured to: the second cutting teeth are disposed behind the first cutting teeth in a circumferential direction formed by rotation of the drill bit;

the position of the second cutter on the PDC bit is configured to: for each of said second cutting teeth, is co-orbital with at least one of said first cutting teeth.

2. The PDC bit of claim 1, wherein the filler body is a structure fabricated from tungsten carbide and/or cemented carbide.

3. The PDC bit of claim 1 or 2, wherein the other end of the flute extends through to the side of the first cutter, the flute having a decreasing cross-sectional dimension in a direction from the leading face of the first cutter to the trailing face of the first cutter.

4. The PDC bit of claim 1 or 2 wherein the other end of the flute extends through to the rear face of the first cutter.

5. The PDC drill bit of claim 1, wherein the distance between the second cutter and the PDC drill bit axis is greater than one-half of the drill bit radius.

6. The PDC bit of claim 5 wherein the second cutting tooth is a cone or axe-type tooth.

7. The PDC bit of claim 5 wherein the second cutting tooth has a land height that is less than or equal to a land height of the first cutting tooth.

8. The PDC bit of claim 1, wherein the cross-section of the flutes comprises a cone, a circle, an oval, or a rectangle.