PDC odd-shaped tooth with corrugated working face

Abstract

The application discloses a PDC special-shaped tooth with a corrugated working surface, which comprises a cylindrical cemented carbide base and a polycrystalline diamond layer arranged at the end of the cemented carbide base, the polycrystalline diamond layer and the cemented carbide base are combined into a composite structure through sintering, the outer end surface of the polycrystalline diamond layer constitutes a working surface, a plurality of corrugated units are arranged continuously along one direction of the working surface, each wave crest part extends along a direction intersecting with the corrugated fluctuation direction, so that a plurality of spaced ridge-shaped areas are formed on the working surface; the PDC cutting tooth with the corrugated working surface is designed according to the characteristics of high-strength wear-resistant organisms in nature, the wear resistance of the cutting tooth is improved, the rock penetration capacity of the cutting tooth is increased, a plurality of cracks can be mutually penetrated and form large-scale broken areas, rock crack propagation is induced to be more, and the rock breaking efficiency of the cutting tooth is improved.

Description

Technical Field

[0001] This invention relates to the field of rock breaking and drilling tools, and in particular to a PDC profiled tooth with a corrugated working surface. Background Technology

[0002] Polycrystalline diamond compact (PDC) cutting teeth are widely used in oil and gas drilling, geothermal drilling, mining, and rock breaking due to their high hardness, wear resistance, and long service life. PDC cutting teeth are typically composed of a polycrystalline diamond layer and a cemented carbide matrix. During operation, they penetrate the formation under the combined action of drilling pressure and cutting motion, breaking the rock through compression, shearing, and crack propagation.

[0003] The shape of the cutting tooth's working face directly affects the initial contact area between the cutting tooth and the formation, the distribution of contact stress, the location of crack initiation, the path of rock cuttings removal, and the cutting tooth's ability to withstand impact loads. Conventional planar PDC cutting teeth tend to form a relatively continuous contact area when contacting the formation, with the load distributed over a large area. Although the structure is stable, its local penetration capability is limited. Using a single peak or ridge structure can reduce the initial contact area and improve penetration capability, but the sharp parts are prone to chipping, dulling, or local failure under the impact of pebbles, gravel, or medium-hard rock layers.

[0004] Different geological formations place different requirements on the working face structure of PDC cutting teeth. Gravel layers contain large, irregularly shaped pebbles that are prone to instantaneous impact, requiring cutting teeth with strong impact resistance. Softer mud layers have lower overall strength but are prone to adhesion and compression deformation, necessitating rapid penetration by the cutting teeth. Gravel layers consist of many discrete particles, generating continuous impacts while requiring timely removal of broken particles. Medium-hard rock layers possess a certain compressive strength, necessitating a balance between impact resistance and penetration. Existing single working face structures are insufficient to simultaneously adapt to these significantly different geological formations.

[0005] The continuous textures of natural surfaces such as seashells can disperse localized loads when subjected to external forces and form multi-point contacts through repeated undulations. Inspired by this type of surface texture, repeating crests and troughs can be incorporated into the working surface of PDC cutting teeth. However, different waveforms exhibit varying degrees of curvature continuity, peak sharpness, and trough openness, resulting in different impact resistance, intrusion resistance, and chip removal characteristics. Therefore, there is a need to provide a PDC profiled tooth with multiple selectable corrugated structures, enabling the working surface waveform to be matched according to formation characteristics. Summary of the Invention

[0006] The purpose of this invention is to provide a PDC non-circular tooth with a corrugated working surface to solve the problems of insufficient local penetration capability and limited impact resistance of conventional planar PDC cutting teeth and single sharp structure. By using different geometric features of circular arc corrugated units, sawtooth corrugated units, cosine corrugated units and trapezoidal corrugated units, the cutting tooth can be adapted to pebble layers, softer soil layers, gravel layers and medium-hard rock layers respectively. Under the condition of adapting to different strata, the rock breaking efficiency of the cutting tooth can also be improved.

[0007] The technical solution adopted by the present invention to achieve the above objectives is as follows: A PDC profiled tooth with a corrugated working surface includes a cylindrical cemented carbide substrate and a polycrystalline diamond layer disposed at the end of the cemented carbide substrate. The polycrystalline diamond layer and the cemented carbide substrate are sintered to form a composite structure. The outer end face of the polycrystalline diamond layer constitutes the working surface. Multiple corrugated units are continuously arranged along one direction of the working surface, and each crest extends along a direction intersecting the corrugation undulation direction, thereby forming multiple spaced ridge-like regions on the working surface.

[0008] Preferably, the corrugated units on the working surface are circular arc corrugated units, each circular arc corrugated unit adopts the same circular arc profile, corrugation height difference H and period P, and is connected sequentially along the corrugation undulation direction.

[0009] Preferably, the corrugated units on the working surface are sawtooth corrugated units, and the corrugation extension direction is adapted to the cutting motion or flushing flow direction.

[0010] Preferably, the corrugated units on the working surface are cosine corrugated units, and adjacent crests and troughs are connected by a continuous smooth curved surface when used in gravel layers.

[0011] Preferably, the corrugated units on the working surface are trapezoidal corrugated units.

[0012] Preferably, the corrugated units on the working surface are primary corrugated units and secondary corrugated units that are alternately arranged along the corrugation undulation direction. The primary corrugated units adopt a large-scale arc shape, and the secondary corrugated units adopt a small pointed or arc shape located between adjacent primary corrugated units.

[0013] Preferably, the primary corrugated unit first bears the impact caused by pebbles or hard particles, and the secondary corrugated unit forms additional contact points after further intrusion and is exposed after the primary corrugated unit wears out, thus realizing the regeneration function of the corrugated tooth unit.

[0014] The beneficial effects of this invention are: Compared with the prior art, the present invention has the following beneficial effects: This invention draws design inspiration from the characteristics of high-strength and wear-resistant organisms in nature, and designs a PDC cutting tooth with a corrugated working surface. This not only improves the wear resistance of the cutting tooth, but also increases its ability to penetrate rock. Multiple cracks can interpenetrate and form a large-scale fracture zone, inducing more crack propagation in the rock and improving the rock-breaking efficiency of the cutting tooth. This invention designs four different corrugated structures for different lithologies. The circular arc corrugated unit features a continuous convex arc and strong impact resistance, capable of withstanding large instantaneous loads from pebbles, making it suitable for pebble layers. The sawtooth corrugated unit exhibits the best initial intrusion performance among the four single waveforms; when used in softer soil layers with less impact, it can leverage its intrusion advantage and reduce the risk of tip damage. The cosine corrugated unit has a continuous and smooth peak-valley curve, capable of dispersing impact loads and providing a discharge path for gravel particles and rock fragments through smoothed troughs, making it suitable for gravel layers. The trapezoidal corrugated unit combines moderate impact resistance and good intrusion, making it suitable for medium-hard rock layers. This invention proposes a cutting tooth composed of multi-level corrugated units. The first-level corrugated units and the second-level corrugated units form a multi-level contact structure of different scales, which can cause the main load, initial crack induction and secondary crack replenishment to occur at different locations, thereby improving the adaptability of the structure to complex or mixed strata. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are used to understand the invention. They do not constitute an improper limitation of the invention. In the drawings: Figure 1 This is an overall schematic diagram of the PDC irregular tooth with a corrugated working surface according to the present invention; Figure 2 This is a schematic diagram of the design of the corrugated working surface in this invention; Figure 3 This is a schematic diagram of the circular arc corrugated unit in this invention; Figure 4 This is a schematic diagram of the sawtooth corrugated unit in this invention; Figure 5 This is a schematic diagram of the cosine wave unit in this invention; Figure 6 This is a schematic diagram of the trapezoidal corrugated unit in this invention; Figure 7 This is a schematic diagram of the multi-level corrugated unit in this invention; Figure 8 This is a schematic diagram comparing the rock-breaking process of the PDC irregular-shaped tooth with a corrugated working surface in this invention with that of a traditional planar cutting tooth. The reference numerals in the accompanying drawings of this invention are as follows: 1. Hard alloy matrix; 2. Polycrystalline diamond layer; 3. Working surface; 31. Circular arc corrugated unit; 32. Sawtooth corrugated unit; 33. Cosine corrugated unit; 34. Trapezoidal corrugated unit; 4. Corrugated crest; 5. Corrugated trough; 6. First-level corrugated unit; 7. Second-level corrugated unit; H, Corrugated height difference; P, Period. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0017] like Figure 1 and Figure 2 As shown, the PDC profiled tooth of this embodiment includes a cylindrical cemented carbide substrate 1 and a polycrystalline diamond layer 2 disposed at the end of the cemented carbide substrate 1. The polycrystalline diamond layer 2 and the cemented carbide substrate 1 are sintered under high temperature and high pressure to form a composite structure. The outer end face of the polycrystalline diamond layer 2 constitutes the working surface 3. Multiple corrugated units are continuously arranged along one direction of the working surface 3, and each corrugated crest 4 extends in a direction intersecting with the corrugation undulation direction, thereby forming multiple spaced ridge-like regions on the working surface 3.

[0018] The corrugated working surface can be formed during the sintering process of the polycrystalline diamond composite sheet using a mold that matches the corrugated profile, or it can be formed using a suitable precision machining method while ensuring the integrity of the polycrystalline diamond layer 2. The corrugated units on the working surface 3 preferably cover the main cutting contact area; when it is necessary to retain the peripheral support structure, they can also be set only in the middle of the working surface 3 or in the predetermined contact area.

[0019] Example 1: The pebble layer uses a circular arc corrugated structure; like Figure 3 As shown, the corrugated units on the working surface 3 are circular arc corrugated units 31. Each circular arc corrugated unit 31 adopts the same circular arc profile, corrugation height difference H, and period P, and is connected sequentially along the corrugation undulation direction. When the PDC irregular tooth is used for the pebble layer, multiple circular arc crests 4 are sequentially contacted with the pebble surfaces of different shapes. The outwardly convex arc can expand the effective bearing range and make the contact point move along the arc during the impact, thereby reducing the situation where the fixed tip bears all the impact.

[0020] Because the trough 5 of the circular corrugated unit 31 is relatively narrow, sufficient flushing medium should be used during drilling, and the extension direction of the trough 5 should preferably be arranged in a direction that facilitates the movement of mud and sand towards the outer edge of the working face 3. When the formation contains a large amount of sticky fine mud, the cosine corrugated unit 33 should be selected or the flushing conditions should be adjusted according to the amount of mud and sand remaining.

[0021] Example 2: A sawtooth corrugated structure is used for softer soil layers; like Figure 4 As shown, the corrugated units set on the working face 3 are sawtooth corrugated units 32. Under drilling pressure, the sawtooth crests 4 are first pressed into the softer soil layer, and then the inclined surfaces on both sides expand the cutting area and apply shearing action to the soft soil. Since the soft soil has less impact on the pointed crests 4, the possibility of sawtooth tip breakage can be reduced, allowing the high penetration capability of the sawtooth structure to be fully utilized. To avoid the accumulation of cohesive soil in the pointed troughs 5, the corrugation extension direction can be matched with the cutting motion or flushing flow direction.

[0022] Example 3: The gravel layer uses a cosine corrugated structure; like Figure 5 As shown, the corrugated units on the working surface 3 are cosine corrugated units 33. Adjacent crests 4 and troughs 5 are connected by a continuous smooth curved surface. When used in gravel layers, the smooth crests 4 can withstand multiple impacts from gravel particles, and the continuously changing curved surfaces on both sides of the crests disperse the load to the surroundings; the crushed particles can be discharged from the working surface 3 along the smooth troughs 5 and the corrugation extension direction. This structure avoids the shortcomings of sawtooth tips being easily damaged and the narrow troughs of the arc units being prone to accumulating fine materials, making it suitable for gravel layers that require both impact resistance and chip removal.

[0023] Example 4: Trapezoidal corrugated structure for medium-hard rock strata; like Figure 6 As shown, the corrugated units on the working face 3 are trapezoidal corrugated units 34. The crest 4 formed at the peak initially contacts the medium-hard rock; its limited width results in a higher contact stress than a conventional planar working face, while simultaneously preventing all the load from concentrating on a single tip. As the intrusion depth increases, the inclined surfaces on both sides participate in the contact, applying compression and shearing forces to the rock; the valley section maintains the interval between adjacent crests 4, providing space for localized rock deformation and crack propagation. This structure is suitable for medium-hard rock formations that require a balance between crest stability, impact resistance, and intrusion capability.

[0024] Example 5: Multi-stage corrugated structure for complex strata; like Figure 7As shown, the corrugated units set on the working face 3 are primary corrugated units 6 and secondary corrugated units 7 arranged alternately along the corrugation undulation direction. The primary corrugated units 6 adopt a larger arc shape, while the secondary corrugated units 7 adopt a smaller pointed or arc shape located between adjacent primary corrugated units 6. The primary corrugated units 6 preferentially bear the impact caused by pebbles or hard particles. The secondary corrugated units 7 form additional contact points after further intrusion and are exposed after the primary corrugated units 6 are worn, realizing the regeneration function of the corrugated tooth units. This structure can be used in complex strata with mixed soft and hard particles, local pebbles, or frequent changes in lithology.

[0025] like Figure 8 As shown, compared with the traditional planar working surface, multiple primary corrugated units 6 and secondary corrugated units 7 can form more numerous and spaced local contact zones on the rock surface. Initial cracks are formed below the local contact zones. As the load increases, the cracks extend to adjacent local contact zones and converge, making it easier for the rock blocks between the crests to lose their restraint and be peeled off.

[0026] The above embodiments illustrate four single-waveform and multi-level corrugated structures. The selection of the circular arc corrugated unit 31, sawtooth corrugated unit 32, cosine corrugated unit 33, and trapezoidal corrugated unit 34 should be based on the main failure load, hardness, particle size, mud content, and debris removal conditions of the target formation. Any equivalent transformations of the crest 4, trough 5, corrugation height difference H, period P, and basic geometric relationships of each waveform as defined in the claims are within the scope of this invention.

Claims

1. A PDC profiled tooth with a corrugated working surface, characterized in that: It includes a cylindrical cemented carbide substrate (1) and a polycrystalline diamond layer (2) disposed at the end of the cemented carbide substrate (1). The polycrystalline diamond layer (2) and the cemented carbide substrate (1) are sintered to form a composite structure. The outer end face of the polycrystalline diamond layer (2) constitutes the working surface (3). Multiple corrugated units are continuously arranged along one direction of the working surface (3). Each crest (4) extends along the direction intersecting with the corrugation undulation direction, thereby forming multiple spaced ridge-like regions on the working surface (3).

2. The PDC profiled tooth with a corrugated working surface according to claim 1, characterized in that: The corrugated unit set on the working surface (3) is a circular arc corrugated unit (31). Each circular arc corrugated unit (31) adopts the same circular arc profile, corrugation height difference H and period P, and is connected in sequence along the corrugation undulation direction.

3. A PDC profiled tooth with a corrugated working surface according to claim 1, characterized in that: The corrugated unit set on the working surface (3) is a sawtooth corrugated unit (32), and the corrugation extension direction is adapted to the cutting motion or flushing flow direction.

4. A PDC profiled tooth with a corrugated working surface according to claim 1, characterized in that: The corrugated unit set on the working surface (3) is a cosine corrugated unit (33), and the adjacent crests (4) and troughs (5) are connected by a continuous smooth curved surface, which is used for gravel layers.

5. A PDC profiled tooth with a corrugated working surface according to claim 1, characterized in that: The corrugated unit set on the working surface (3) is a trapezoidal corrugated unit (34).

6. A PDC profiled tooth with a corrugated working surface according to claim 1, characterized in that: The corrugated units set on the working surface (3) are primary corrugated units (6) and secondary corrugated units (7) that are alternately arranged along the corrugation undulation direction. The primary corrugated unit (6) adopts a large-scale arc shape, and the secondary corrugated unit (7) adopts a small pointed or arc shape located between adjacent primary corrugated units (6).

7. A PDC profiled tooth with a corrugated working surface according to claim 6, characterized in that: The primary corrugated unit (6) first bears the impact caused by pebbles or hard particles. The secondary corrugated unit (7) forms additional contact points after further intrusion and is exposed after the primary corrugated unit (6) wears out, thus realizing the regeneration function of the corrugated tooth unit.

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