Composite rock breaking configuration PDC (Polycrystalline Diamond Compact) drill bit

Abstract

The invention relates to the technical field of oil exploration, in particular to a composite rock breaking configuration PDC drill bit which comprises a drill bit body. The multiple cutting ribs are arranged on the drill bit body and extend towards the central axis of the drill bit body, cutting blades are arranged on the two sides of each cutting rib, and cutting teeth and hard alloy teeth are arranged on the lip surfaces of the cutting blades; chip grooves are formed among the multiple cutting ribs, the height of the cutting teeth is larger than that of the hard alloy teeth, a preset height difference exists between the cutting teeth and the hard alloy teeth, and a preset distance exists between the cutting teeth and the hard alloy teeth in the width direction of the cutting ribs. The problems that PDC cutting teeth of a PDC drill bit selected in a similar well section with fierce interaction of flint, a gravel interlayer, a stratum and the like during well drilling are easy to crack and fast to wear; the problems that the drilling efficiency is low and the machine speed is too low when a roller bit is selected are solved.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum exploration, and in particular to a PDC drill bit with a composite rock-breaking configuration. Background Art

[0002] The drill bit is the main tool for breaking rocks during the drilling process. The wellbore is formed by the drill bit breaking rocks. The quality of a wellbore and the length of time it takes to form it are related not only to the characteristics of the rock formation being drilled and the performance of the drill bit itself, but also to the degree of mutual matching between the drill bit and the formation. The reasonable selection of the drill bit plays an important role in increasing the drilling speed and reducing the overall drilling cost.

[0003] When drilling in well sections with flint, gravel interlayers, and severe strata interaction, if a PDC drill bit is used, the PDC cutter teeth are prone to cracking and rapid wear due to the low impact resistance of the composite cutter teeth; if a roller drill bit is used, there will be problems such as low drilling efficiency and slow machine speed, which will affect the drilling cycle and production development progress. Summary of the invention

[0004] The embodiment of the present invention provides a PDC drill bit with a composite rock-breaking configuration, which can solve the problems of easy cracking and rapid wear of PDC cutting teeth in the existing PDC drill bits used in well sections with flint, gravel interlayers, severe strata interaction, etc., and the problems of low drilling efficiency and slow machine speed in the existing roller drill bits.

[0005] The embodiment of the present application provides a composite rock breaking configuration PDC drill bit, comprising:

[0006] Drill bit body;

[0007] A plurality of cutting ribs are provided on the drill body and extend toward the central axis of the drill body, the two sides of the cutting ribs are provided with cutting blades, and the lip surfaces of the cutting blades are provided with cutting teeth and cemented carbide teeth;

[0008] Among them, a chip groove is formed between the plurality of cutting ribs, the height of the cutting teeth is greater than the height of the cemented carbide teeth, and there is a preset height difference between the cutting teeth and the cemented carbide teeth, and there is a preset spacing between the cutting teeth and the cemented carbide teeth in the width direction of the cutting ribs.

[0009] In some embodiments, the plurality of cutting ribs are arranged in a spiral line, and the plurality of cutting ribs is five cutting ribs.

[0010] In some embodiments, the cutting teeth are arranged using the equal wear tooth arrangement principle.

[0011] In some embodiments, the cutting teeth are of a semi-exposed cutting edge structure, the back rake angle of the cutting teeth is 14° to 16°, and the side rake angle of the cutting teeth is 0° to 10°.

[0012] In some embodiments, the drill bit body is provided with a chip removal groove nozzle and a center nozzle. The chip removal groove nozzle is arranged in the chip removal groove, and the center nozzle is arranged in the middle of the drill bit body.

[0013] In some embodiments, the cutting ribs include a crown portion and a neck protection portion. The cutting teeth and the cemented carbide teeth are arranged on the crown portion, and a plurality of gauge protection teeth are arranged on the neck protection portion. The gauge protection teeth are cylinders.

[0014] In some embodiments, the crown portion is of a long parabolic configuration.

[0015] In some embodiments, the gauge protection teeth include a polycrystalline diamond layer and a cemented carbide matrix connected to the polycrystalline diamond layer.

[0016] In some embodiments, the composite rock-breaking configuration PDC drill bit further includes a sub, and the sub is connected to one end of the drill bit body away from the cutting ribs.

[0017] In some embodiments, the preset height difference is 1-2 mm, and the preset spacing is 10-20 mm.

[0018] Compared with the prior art, in the embodiment of the present application, by arranging cutting teeth and cemented carbide teeth on the lip surface of the cutting blade and making the height of the cutting teeth greater than the height of the cemented carbide teeth, when the cutting teeth penetrate into the ground, the cemented carbide teeth break the rock by means of gouging and shearing, delaying the chipping and wear of the cutting teeth; by arranging a plurality of cutting ribs on the drill bit body, chip removal grooves are formed between the plurality of cutting ribs, and the mud can be discharged in time, reducing the erosion of the mud on the drill bit and improving the service life of the drill bit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the drawings.

[0020] Figure 1 is a schematic structural diagram of a composite rock-breaking configuration PDC drill bit provided by an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of the circumferential tooth arrangement of a composite rock-breaking configuration PDC drill bit provided by an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of the radial tooth arrangement of a composite rock-breaking configuration PDC drill bit provided by an embodiment of the present invention;

[0023] Figure 4It is the cutting area distribution diagram of the cutting teeth provided by an embodiment of the present invention;

[0024] Figure 5 It is the cutting volume distribution diagram of the cutting teeth provided by an embodiment of the present invention.

[0025] Reference numerals:

[0026] 10. Drill bit body; 110. Chip removal groove nozzle; 120. Central nozzle;

[0027] 20. Cutting rib; 210. Crown; 220. Protected neck; 2201. Gauge tooth; 230. Cutting blade; 240. Cutting tooth; 250. Cemented carbide tooth;

[0028] 30. Chip removal groove. Detailed implementation manners

[0029] The present invention will be further described below in conjunction with the accompanying drawings.

[0030] A polycrystalline diamond compact (PDC) drill bit, abbreviated as PDC drill bit. It is made by embedding or sintering small cutting blocks made of polycrystalline diamond (thin circular sheets) onto the drill bit body. It is used in soft to medium-hard formations; the roller cone bit is one of the most widely used drilling bits. When the roller cone bit works, the cutting teeth alternately contact the bottom of the well, the rock-breaking torque is small, the contact area between the cutting teeth and the bottom of the well is small, the specific pressure is high, and it is easy to penetrate into the formation; the total length of the working edges is large, so the wear is relatively reduced. The roller cone bit can adapt to a variety of formations from soft to hard.

[0031] During the drilling process, the drill bit is the main tool for breaking rocks, and the wellbore is formed by the drill bit breaking rocks. The quality of a wellbore formed and the length of time used are not only related to the characteristics of the formation rocks being drilled and the performance of the drill bit itself, but more importantly, related to the degree of mutual matching between the drill bit and the formation. The reasonable selection of the drill bit plays an important role in improving the drilling speed and reducing the comprehensive drilling cost.

[0032] During the drilling process of the drill bit, the drill bit interacts with the rock. While breaking the rock, it will also be worn by the reaction force of the rock. Especially when drilling in formations with similar lithological characteristics such as formations containing flint and gravel interlayers and severe formation alternation, when transitioning from one lithology to another, or from one compressive environment to another, due to the rapid change in lithology, the penetration depth of the cutting teeth is inconsistent, the torque fluctuates greatly, and the drill bit will generate high instantaneous impact forces, cyclic lateral forces, and vibrations at the bottom of the well. Due to the strong vibrations, the PDC drill bit will experience breakage, cracks, and a large number of cutting teeth fractures. All of these are attributed to the severe impact on the diamond surface of the drill bit. At the same time, drilling in such formations will also generate a large cutting tooth load, which will cause the drill bit to vibrate disorderly, and in turn cause impact damage to the cutting teeth. And as the worn surface of the cutting teeth expands, it will cause frictional heat generation at the interface between the cutting teeth and the rock, thereby weakening the diamond cutting components.

[0033] During the drilling process, when encountering sections with similar conditions such as flint, gravel interlayers, and severe formation alternation, it is very difficult to select the drill bit. If a PDC drill bit is selected, when drilling through flint and gravel interlayers, due to the low impact resistance of the composite insert cutting teeth, the PDC teeth are extremely prone to cracking and rapid wear, resulting in premature failure of the PDC drill bit; if a roller cone drill bit is selected, problems such as low drilling efficiency and slow penetration rate will occur. This seriously affects the drilling cycle and the progress of production and development. In the sections where flint, gravel interlayers, or severe formation alternation are drilled, the drill bit is often replaced frequently due to premature failure of the drill bit, which seriously affects the drilling cycle and the progress of production and development and increases the drilling cost.

[0034] In view of the above technical problems, as Figure 1 shown, the embodiment of the present application provides a PDC drill bit with a composite rock-breaking configuration, including:

[0035] A drill bit body 10;

[0036] A plurality of cutting ribs 20 are arranged on the drill bit body 10 and extend towards the central axis of the drill bit body 10. Both sides of the cutting rib 20 have cutting wings 230, and cutting teeth 240 and cemented carbide teeth 250 are arranged on the lip surface of the cutting wing 230;

[0037] Among them, a chip removal groove 30 is formed between the plurality of cutting ribs 20. The height of the cutting teeth 240 is greater than the height of the cemented carbide teeth 250, and there is a preset height difference between the cutting teeth 240 and the cemented carbide teeth 250. The cutting teeth 240 and the cemented carbide teeth 250 have a preset spacing in the width direction of the cutting rib 20.

[0038] It should be noted that multiple cutting ribs 20 are provided on the upper part of the drill bit body 10. The cutting ribs 20 extend from the side surface of the drill bit body 10 towards the central axis of the upper end surface of the drill bit body 10. By providing cutting teeth 240 and cemented carbide teeth 250 on the lip surface of the cutting blade 230, and making the height of the cutting teeth 240 greater than the height of the cemented carbide teeth 250, when the cutting teeth 240 penetrate into the ground, the cemented carbide teeth 250 break the rock by means of gouging and shearing, delaying the chipping and wear of the cutting teeth 240.

[0039] It should be noted that the cutting teeth 240 are composed of a polycrystalline diamond layer and a cemented carbide base. During the cutting process, the cutting edge of the cutting teeth 240 can self-sharpen. After the sharp cutting edge cuts into the rock formation, it moves forward under the action of torque, and the PDC drill bit shears the rock, making full use of the weakness of the low shear strength of the rock.

[0040] In some embodiments, the multiple cutting ribs 20 are arranged in a spiral. The multiple cutting ribs 20 are five cutting ribs 20.

[0041] It should be noted that the multiple cutting ribs 20 arranged in a spiral can be arranged clockwise or counterclockwise. The multiple cutting ribs 20 arranged in a spiral make the chip removal grooves 30 between the multiple cutting ribs 20 be arranged in a spiral shape. While including the flow area, the chip removal grooves 30 can buffer and release the lateral impact energy, hierarchically release and transfer and absorb the impact energy generated during the drilling process. Moreover, the streamlined design configuration of the chip removal grooves 30 can improve the mud flow, obtain a higher shear stress along the surface of the cutting ribs 20, reduce the secondary circulation of the fluid on the drill bit surface, enhance the chip removal ability and the wellbore cleaning effect. And it reduces the erosion of the cuttings by the mud carrying the cuttings, reduces the probability of the drill bit being mud-packed, and at the same time improves the stability of the drill bit during drilling, thereby improving the mechanical drilling speed and the direction control force.

[0042] It should be noted that as Figure 1 shown, when there are five cutting ribs 20, there can be two main cutting ribs 20 with longer lengths and three secondary cutting ribs 20 with shorter lengths. Main cutting wings are formed on both sides of the main cutting ribs 20, and secondary cutting wings are formed on both sides of the secondary cutting ribs 20. Cutting teeth 240 and cemented carbide teeth 250 are provided on the lip surfaces of the main cutting wings and the secondary cutting wings, which are jointly used for cutting the formation.

[0043] In some embodiments, the cutting teeth 240 are arranged according to the equal wear tooth arrangement principle.

[0044] It should be noted that as Figure 2 、 Figure 3 shown, adopting the equal wear tooth arrangement principle can achieve the effect of equal wear of each cutting tooth 240 of the PDC drill bit during the drilling rock-breaking process, avoiding the problem of frequent drill bit replacement caused by the wear of a small number of cutting teeth 240.

[0045] In some embodiments, the cutting tooth 240 has a semi-exposed structure, the back rake angle of the cutting tooth 240 is 14° to 16°, and the side rake angle of the cutting tooth 240 is 0° to 10°.

[0046] It should be noted that when the back rake angle is small, it is suitable for soft formations, and when the back rake angle is large, it is suitable for harder formations. Generally, the back rake angle is 0° to 35°. In this embodiment, by making the cutting tooth 240 have a semi-exposed structure, the back rake angle of the cutting tooth 240 is 14° to 16°, and the side rake angle of the cutting tooth 240 is 0° to 10°, the cutting tooth 240 can be suitable for use in soft to medium-hard formations such as flint and gravel formations.

[0047] It should be noted that by setting the semi-exposed structure of the cutting tooth 240, the back rake angle to 14° to 16°, and the side rake angle to 0° to 10°, after performing simulation calculations, the distribution diagrams of the number of cutting ribs 20 and the cutting area as shown in Figure 4 and the distribution diagrams of the number of cutting ribs 20 and the cutting volume as shown in Figure 5 are obtained. They both show that when five cutting ribs 20 are set, the cutting efficiency is relatively high. Therefore, five cutting ribs 20 can be set.

[0048] In some embodiments, the drill bit body 10 is provided with a chip removal groove nozzle 110 and a center nozzle 120. The chip removal groove nozzle 110 is arranged in the chip removal groove 30, and the center nozzle 120 is arranged in the middle of the drill bit body 10.

[0049] It should be noted that both the chip removal groove nozzle 110 and the center nozzle 120 are arranged on the upper end surface of the drill bit body 10. The center nozzle 120 is located at the front end of the two main cutting ribs 20. Both the chip removal groove nozzle 110 and the center nozzle 120 are connected to the central flow channel in the drill bit body 10. During operation, the drilling fluid is ejected from the chip removal groove nozzle 110 and the center nozzle 120 through the central flow channel to clean and cool the drill bit, and carry the cut rock chips out of the wellhead through the chip removal groove 30 and the annulus.

[0050] In some embodiments, the cutting rib 20 includes a crown part 210 and a neck protection part 220. The crown part 210 is provided with cutting teeth 240 and cemented carbide teeth 250. The neck protection part 220 is provided with a plurality of gauge teeth 2201, and the gauge teeth 2201 are cylinders.

[0051] In some embodiments, the gauge tooth 2201 includes a polycrystalline diamond layer and a cemented carbide matrix connected to the polycrystalline diamond layer.

[0052] It should be noted that the polycrystalline diamond layer and the cemented carbide substrate are sintered into one body under high temperature and high pressure. The gauge protection tooth 2201 is a cylinder, and the polycrystalline diamond layer is sintered at one end of the top of the cylinder and arranged on the surface of the gauge protection part of the drill bit. Each gauge protection neck 220 can be arranged with 9-10 pieces. During the drilling process of the drill bit, the gauge protection tooth 2201 interacts with the wellbore wall, which can enhance the outer diameter scraping ability of the drill bit, ensure that the drill bit receives lower torque and resistance, balance the radial vibration load generated at the bottom of the well, effectively reduce the wear of the wellbore wall on the surface of the cutter blade of the drill bit, enhance the wear resistance and stability of the cutter blade, and thus protect the outer diameter of the cutting rib 20 of the drill bit.

[0053] In some embodiments, the crown 210 has a long parabolic configuration.

[0054] It should be noted that by making the crown 210 of the cutting rib 20 have a long parabolic configuration, the stability of the drill bit can be improved, and it is applicable to softer and more abrasive formations, that is, applicable to flint and gravel formations.

[0055] In some embodiments, the composite rock-breaking configuration PDC drill bit further includes a sub, and the sub is connected to one end of the drill bit body 10 away from the cutting rib 20.

[0056] In some embodiments, the preset height difference is 1-2 mm, and the preset spacing is 10-20 mm.

[0057] It should be noted that during the drilling process of the drill bit, that is, on the basis of ordinary rotary drilling, when the cutting tooth 240 penetrates into the formation by 1 mm or 2 mm, the cemented carbide tooth 250 interacts with the formation, and the cemented carbide tooth 250 breaks the rock by a combination of gouging and shearing, protecting the cutting tooth 240 participating in rock breaking from early failure. The self-adaptive tooth arrangement technology, that is, the equal wear tooth arrangement principle, not only improves the impact resistance but also does not affect the drilling speed. The steel body structure makes the cutter blade have strong impact toughness.

[0058] In summary, compared with the prior art, in the embodiment of the present application, by arranging the cutting tooth 240 and the cemented carbide tooth 250 on the lip surface of the cutting cutter blade 230 and making the height of the cutting tooth 240 greater than the height of the cemented carbide tooth 250, when the cutting tooth 240 penetrates into the ground, the cemented carbide tooth 250 breaks the rock by gouging and shearing, delaying the chipping and wear of the cutting tooth 240; by arranging a plurality of cutting ribs 20 on the drill bit body 10, a chip removal groove 30 is formed between the plurality of cutting ribs 20, which can timely discharge the mud, reduce the erosion of the mud on the drill bit, and improve the service life of the drill bit.

[0059] It should be understood that in the description of the present invention, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more. In the description of the present invention, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween.

[0060] In the description of the present invention, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature.

[0061] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0062] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0063] Although the present invention has been described with reference to preferred embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A composite rock-breaking configuration PDC bit, characterized in that, Comprising: A drill bit body (10); A plurality of cutting ribs (20) provided on the drill bit body (10) and extending towards the central axis of the drill bit body (10), with cutting wings (230) on both sides of the cutting ribs (20), and cutting teeth (240) and cemented carbide teeth (250) provided on the lip surface of the cutting wings (230); Wherein, chip flutes (30) are formed between the plurality of cutting ribs (20), the height of the cutting teeth (240) is greater than the height of the cemented carbide teeth (250), and there is a preset height difference between the cutting teeth (240) and the cemented carbide teeth (250), and there is a preset spacing between the cutting teeth (240) and the cemented carbide teeth (250) in the width direction of the cutting ribs (20).

2. The composite rock-breaking configuration PDC bit according to claim 1, wherein The plurality of cutting ribs (20) are arranged in a spiral, and the plurality of cutting ribs (20) are five cutting ribs (20).

3. The composite rock-breaking configuration PDC bit according to claim 1, wherein The cutting teeth (240) are arranged according to the principle of equal wear tooth arrangement.

4. The PDC bit with a composite rock-breaking configuration according to claim 1, wherein The cutting teeth (240) are of a semi-exposed edge structure, the back rake angle of the cutting teeth (240) is 14° - 16°, and the side rake angle of the cutting teeth (240) is 0° - 10°.

5. The PDC bit with a composite rock-breaking configuration according to claim 1, wherein A chip flute nozzle (110) and a central nozzle (120) are provided on the drill bit body (10), the chip flute nozzle (110) is provided in the chip flute (30), and the central nozzle (120) is provided in the middle of the drill bit body (10).

6. The PDC bit with a composite rock-breaking configuration according to claim 1, wherein The cutting rib (20) includes a crown portion (210) and a neck protection portion (220), the cutting teeth (240) and the cemented carbide teeth (250) are provided on the crown portion (210), and a plurality of gauge teeth (2201) are provided on the neck protection portion (220), and the gauge teeth (2201) are cylinders.

7. The PDC bit with a composite rock-breaking configuration according to claim 6, wherein The crown portion (210) is of a long parabolic configuration.

8. The composite rock-breaking configuration PDC bit according to claim 6, wherein The gauge teeth (2201) include a polycrystalline diamond layer and a cemented carbide matrix connected to the polycrystalline diamond layer.

9. The composite rock-breaking configuration PDC bit according to claim 1, characterized in that, The composite rock-breaking configuration PDC drill bit further includes a sub, and the sub is connected to one end of the drill bit body (10) away from the cutting ribs (20).

10. The PDC bit with a composite rock-breaking configuration according to any one of claims 1-9, characterized in that, The preset height difference is 1 - 2 mm, and the preset spacing is 10 - 20 mm.

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