Diamond drill bit and method of manufacturing the same

Abstract

The present application belongs to the technical field of drilling tools, and particularly relates to a diamond drill bit and a manufacturing method thereof, which are used to solve the technical problem of low drilling efficiency of the diamond drill bit. The diamond drill bit comprises a drill bit body, a blade, a first cutting tooth and a second cutting tooth arranged on the blade, the blade is arranged on the side wall of the drill bit body and extends to the first end face of the drill bit body, and the blade comprises a core part, a nose part, a shoulder part and a gauge part in sequence in the direction away from the first end face; the second cutting tooth is used for pre-breaking the target rock stratum, the first cutting tooth comprises a first impact-resistant tooth and a first abrasion-resistant tooth, the first impact-resistant tooth is arranged on the shoulder part and the gauge part, and the first abrasion-resistant tooth is arranged on the core part and the nose part; the second cutting tooth comprises a second impact-resistant tooth and a second abrasion-resistant tooth, the second impact-resistant tooth is arranged on the shoulder part, and the second abrasion-resistant tooth is arranged on the gauge part, so that the arrangement of each cutting tooth is matched with the stress of each cutting tooth, thereby improving the drilling efficiency of the diamond drill bit.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of drilling tools, in particular to a diamond drill bit and a manufacturing method thereof. BACKGROUND

[0002] The diamond drill bit is mainly used in oil exploration drilling, and the diamond drill bit usually comprises a drill bit body, a blade arranged on the drill bit body, and a cutting tooth arranged on the blade, and the rock is damaged by extrusion and shearing of the cutting tooth. The material of the cutting tooth can be polycrystalline diamond compact (PDC for short).

[0003] In the use process of the diamond drill bit, the cutting tooth bears a large impact force, and impact damage is prone to occur when drilling into a high-gravel-containing stratum or a hard stratum, which leads to damage of the cutting tooth and low drilling efficiency. In addition, in the drilling process of a high-temperature and high-pressure gas well, the diamond drill bit needs to drill into a thick gravel layer, and the gravel layer has a complex structure and composition, which includes super-large gravel of the upper part of unconsolidated accumulation, medium-gravel of the quasi-consolidated section, and small-gravel of the lower part with good compaction effect. The gravel composition includes igneous rocks such as basalt and andesite, and metamorphic rocks and carbonate sedimentary rocks, and the drilling efficiency is low due to low drilling footage and slow drilling speed. SUMMARY

[0004] In view of the above problems, the embodiment of the present application provides a diamond drill bit and a manufacturing method thereof for improving the drilling efficiency of the diamond drill bit.

[0005] In order to achieve the above-mentioned purpose, the embodiment of the present application provides the following technical scheme:

[0006] In a first aspect, the embodiment of the present application provides a diamond drill bit, which comprises a drill bit body, a blade arranged on the drill bit body, and first and second cutting teeth arranged on the blade, the blade is arranged on the side wall of the drill bit body and extends to the first end face of the drill bit body, and along the direction away from the first end face, the blade comprises a heart part, a nose part, a shoulder part and a gauge part in sequence; the second cutting tooth is used for pre-breaking a target rock layer, the first cutting tooth comprises a first impact-resistant tooth and a first anti-abrasion tooth, the first impact-resistant tooth is arranged on the shoulder part and the gauge part, and the first anti-abrasion tooth is arranged on the heart part and the nose part; the second cutting tooth comprises a second impact-resistant tooth and a second anti-abrasion tooth, the second impact-resistant tooth is arranged on the shoulder part, and the second anti-abrasion tooth is arranged on the gauge part.

[0007] The diamond drill bit provided by the embodiment of the present application has at least the following advantages:

[0008] The diamond drill bit provided by the embodiment of the present application comprises first cutting teeth and second cutting teeth, the first cutting teeth are used for breaking target rock strata, and the second cutting teeth are used for pre-breaking target rock strata, so that the target rock strata form preliminary cracks through the second cutting teeth, thereby reducing the drilling pressure and torsional force of the first cutting teeth when the target rock strata are broken, improving the footage and drilling speed of the diamond drill bit, and thus improving the drilling efficiency of the diamond drill bit. In addition, the first cutting teeth comprise first impact-resistant teeth and first wear-resistant teeth, the second cutting teeth comprise second impact-resistant teeth and second wear-resistant teeth, the first impact-resistant teeth are arranged on the shoulder part and the gage part, the first wear-resistant teeth are arranged on the center part and the nose part, the second impact-resistant teeth are arranged on the shoulder part, and the second wear-resistant teeth are arranged on the gage part, so that the arrangement of each tooth of the diamond drill bit is matched with the force acting on the tooth, that is, the center part and the nose part of the diamond drill bit, which are more severely worn, are provided with wear-resistant teeth, and the shoulder part, which is more severely impacted, is provided with impact-resistant teeth, thereby improving the impact resistance and wear resistance of the diamond drill bit, further improving the footage and drilling speed of the diamond drill bit, and thus improving the drilling efficiency of the diamond drill bit.

[0009] In the diamond drill bit described above, the first cutting teeth are trilobate teeth, the trilobate teeth comprise a first columnar part, and a central region of an end surface of the first columnar part is provided with a triangular plane, and three vertices of the triangular plane are respectively connected to a ridge.

[0010] In the diamond drill bit described above, the first impact-resistant teeth and the first wear-resistant teeth are obtained by acidizing first original cutting teeth, the acidizing solution comprises a mixed solution of hydrochloric acid and nitric acid, the ratio of hydrochloric acid to nitric acid in the acidizing solution for the first wear-resistant teeth is different from the ratio of hydrochloric acid to nitric acid in the acidizing solution for the first impact-resistant teeth.

[0011] In the diamond drill bit described above, the second cutting teeth are conical teeth, the conical teeth comprise a conical surface part and a second columnar part connected to a bottom surface of the conical surface part.

[0012] In the diamond drill bit described above, the conical angle of the conical surface part is 60°-120°.

[0013] In the diamond drill bit described above, the second impact-resistant teeth and the second wear-resistant teeth are obtained by acidizing second original cutting teeth, the acidizing solution comprises a mixed solution of hydrochloric acid and nitric acid, the ratio of hydrochloric acid to nitric acid in the acidizing solution for the second wear-resistant teeth is different from the ratio of hydrochloric acid to nitric acid in the acidizing solution for the second impact-resistant teeth.

[0014] In the diamond drill bit described above, double rows of teeth are arranged on the blade, and a reverse eye tooth is further arranged on the side of the blade away from the first end surface.

[0015] In a second aspect, the embodiment of the present application further provides a manufacturing method of a diamond drill bit, which comprises:

[0016] Spatially arranging the first cutting tooth and the second cutting tooth;

[0017] Obtaining an abrasion index and an impact index of the target rock formation, and simulating stress conditions of the first cutting tooth and the second cutting tooth under different drilling pressures and rotational speeds according to the abrasion index and the impact index;

[0018] According to the stress conditions, determining that the first cutting tooth selects a first abrasion-resistant tooth or a first impact-resistant tooth, and the second cutting tooth selects a second abrasion-resistant tooth or a second impact-resistant tooth.

[0019] The manufacturing method of the diamond drill bit provided by the embodiment of the present application has the following advantages:

[0020] In the manufacturing method of the diamond drill bit provided by the embodiment of the present application, the stress conditions of the first cutting tooth and the second cutting tooth under different working conditions are simulated according to the abrasion index and the impact index of the target rock formation, and the first cutting tooth selects a first abrasion-resistant tooth or a first impact-resistant tooth, and the second cutting tooth selects a second abrasion-resistant tooth or a second impact-resistant tooth according to the stress conditions, so that the arrangement of each abrasion-resistant tooth and each impact-resistant tooth is matched with the stress, thereby improving the impact resistance and abrasion resistance of the diamond drill bit, and further improving the footage and drilling speed of the diamond drill bit, so as to improve the drilling efficiency of the diamond drill bit.

[0021] In the manufacturing method of the diamond drill bit provided by the embodiment of the present application, when the abrasion index and the impact index of the target rock formation are obtained, logging data is obtained by using natural gamma logging and acoustic logging, and the abrasion index and the impact index of the target rock formation are calculated according to the logging data.

[0022] In the manufacturing method of the diamond drill bit provided by the embodiment of the present application, it further includes: obtaining a plurality of first original cutting teeth and a plurality of second original cutting teeth, and the diamond layer of each first original cutting tooth and each second original cutting tooth is processed into a required shape by electric spark machining;

[0023] Sealing the part of the non-diamond layer of each first original cutting tooth and each second original cutting tooth;

[0024] Performing different acidizing treatments on the exposed diamond layer of each first original cutting tooth and each second original cutting tooth; wherein part of the first original cutting teeth form first abrasion-resistant teeth, part of the first original cutting teeth form first impact-resistant teeth, part of the second original cutting teeth form second abrasion-resistant teeth, and part of the second original cutting teeth form second impact-resistant teeth.

[0025] In addition to the technical problems solved by the embodiments of the present application, the technical features constituting the technical solutions and the beneficial effects brought by the technical features, the other technical problems solved by the diamond drill bit and the manufacturing method thereof, the other technical features included in the technical solutions and the beneficial effects brought by the technical features will be further described in detail in the specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0027] Figure 1 FIG. 1 is a structural schematic diagram of the diamond drill bit in the embodiments of the present application;

[0028] Figure 2 FIG. 2 is a structural schematic diagram of the first cutting tooth in the embodiments of the present application;

[0029] Figure 3 FIG. 3 is a structural schematic diagram of the second cutting tooth in the embodiments of the present application;

[0030] Figure 4 FIG. 4 is a tooth distribution design diagram of the first cutting tooth and the second cutting tooth in the embodiments of the present application;

[0031] Figure 5 FIG. 5 is a distribution diagram of the grinding index and the impact index of the target rock stratum in the embodiments of the present application;

[0032] Figure 6 FIG. 6 is a tooth distribution diagram of the impact-resistant tooth and the grinding-resistant tooth in the embodiments of the present application.

[0033] Explanation of reference signs:

[0034] 100 - diamond drill bit; 110 - drill bit body;

[0035] 120 - blade; 121 - core;

[0036] 122 - nose; 123 - shoulder;

[0037] 124 - gauge portion; 125 - gauge pad;

[0038] 130 - first cutting tooth; 131 - first columnar portion;

[0039] 132 - triangular plane; 133 - ridge;

[0040] 140 - second cutting tooth; 141 - second cylindrical part;

[0041] 142 - conical surface part; 150 - nozzle;

[0042] 160 - back gauge tooth; 170 - chip flute. DETAILED DESCRIPTION

[0043] In order to improve the footage, drilling speed and drilling efficiency of the diamond bit, the diamond bit in the embodiment of the present application is provided with first impact-resistant teeth on the shoulder part and the gauge part of the blade, first abrasion-resistant teeth on the heart part and the nose part of the blade, second impact-resistant teeth on the shoulder part of the blade, and second abrasion-resistant teeth on the gauge part of the blade, the first impact-resistant teeth and the first abrasion-resistant teeth are used for breaking the target rock stratum, and the second impact-resistant teeth and the second abrasion-resistant teeth are used for pre-breaking the target rock stratum, so that the arrangement of each tooth of the diamond bit matches the stress, that is, the heart part and the nose part of the diamond bit which are more severely worn are provided with abrasion-resistant teeth, and the shoulder part which is more severely impacted is provided with impact-resistant teeth, thereby improving the impact resistance and abrasion resistance of the diamond bit, and further improving the drilling efficiency of the diamond bit.

[0044] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0045] Embodiment one

[0046] Reference Figure 1 The embodiments of the present application provide a diamond bit 100, which comprises a bit body 110, blades 120 arranged on the bit body 110, and first cutting teeth 130 and second cutting teeth 140 arranged on the blades 120. The bit body 110 can be substantially in a cylindrical structure, for example, a circular cylindrical structure. The bit body 110 is provided with the blades 120, and the blades 120 can be provided in multiple, for example, six. The multiple blades 120 are arranged at intervals.

[0047] As Figure 1As shown, a plurality of blades 120 are arranged on the sidewall of the drill bit body 110 in the axial direction of the drill bit body 110, and extend to the first end surface of the drill bit body 110. For example, three blades 120 of the six blades 120 in the embodiment are first blades, which extend to the central region of the first end surface, and the other three blades 120 are second blades, which are respectively located between two adjacent first blades and have a spacing with the first blades.

[0048] A chip groove 170 is formed between two adjacent blades 120. For example, a chip groove 170 is respectively formed between a second blade and its two adjacent first blades, and the two chip grooves 170 are connected on the first end surface. The broken rock formed after the rock of the target rock stratum is broken can be guided and discharged through the chip groove 170, so as to reduce the impact load of the broken rock on the first cutting teeth 130 or the second cutting teeth 140 on the blades 120, reduce or avoid the first cutting teeth 130 or the second cutting teeth 140 from being quickly blunted, and improve the drilling speed of the diamond drill bit 100.

[0049] The first end surface of the drill bit body 110 is also provided with a nozzle 150, which is located at the bottom of the chip groove 170 and is connected with the pipeline inside the drill bit body 110. The drilling fluid is divided into the nozzle 150 through the pipeline and is sprayed out of the nozzle 150, which can cool and lower the temperature of the first cutting teeth 130 and the second cutting teeth 140, and also can remove the broken rock in the chip groove 170, so as to improve the service life and drilling efficiency of the diamond drill bit 100.

[0050] The end of the drill bit body 110 away from the first end surface is a joint to connect the drill bit body 110 with other devices. For example, the sidewall of the drill bit body 110 away from the first end surface is provided with an external thread, and the drill bit body 110 is threadedly connected with other devices. The second end surface of the drill bit body 110 opposite to the first end surface exposes the pipeline for the drilling fluid to enter the pipeline.

[0051] Continuing to refer to Figure 1Along the direction away from the first end face, the cutting edge 120 sequentially includes a core portion 121, a nose portion 122, a shoulder portion 123, and a diameter protection portion 124. The core portion 121 refers to the inner conical part of the cutting edge 120, located at the tip of the cutting edge 120, used for guidance and stabilization. The inner conical angle can be 90°-150°, selected according to the operating conditions of the diamond drill bit 100. The nose portion 122 refers to the highest point of the cutting edge 120. Typically, the nose portion 122 is the first to cut into the target rock layer. The radius of the nose portion 122 can be selected according to the operating conditions of the diamond drill bit 100. The shoulder portion 123 includes the outer conical part of the cutting edge 120. The outline of the shoulder portion 123 can be a straight line or a curve; a straight outline provides better penetration, while a curved outline provides better wear resistance. The diameter protection section 124 is located at the tail end of the cutter wing 120 and is used to prevent the diameter of the diamond drill bit 100 from shrinking due to wear of the target rock layer during operation.

[0052] Each blade 120 is provided with a first cutting tooth 130 and a second cutting tooth 140, the first cutting tooth 130 and the second cutting tooth 140 are distributed at intervals, and the first cutting tooth 130 and the second cutting tooth 140 can be brazed onto the blade 120.

[0053] The first cutting tooth 130 is mainly used to shear and break the target rock layer. By overcoming the stress of the target rock layer, it cuts into the target rock layer and moves forward. Under the action of the first cutting tooth 130, the target rock layer is broken along its shear direction and generates plastic flow. The second cutting tooth 140 is mainly used for pre-breaking the target rock layer. The contact area between the second cutting tooth 140 and the target rock layer is smaller and the force is concentrated. It cuts into the target rock layer before the first cutting tooth 130, causing the target rock layer to generate fracture cracks under the action of contact stress, thereby releasing the stress of the target rock layer and weakening its strength, so as to facilitate the drilling of the first cutting tooth 130 and improve drilling efficiency. That is, the second cutting tooth 140 has active anti-vortex capability to reduce the vortex and counter-torque of the diamond drill bit 100.

[0054] In some possible examples, the first cutting tooth 130 and the second cutting tooth 140 are arranged in a single row, that is, the blade 120 is provided with a single row of teeth. In other possible examples, the first cutting tooth 130 and the second cutting tooth 140 are arranged in a double row, that is, as shown in... Figure 1 As shown, the blade 120 is equipped with double rows of teeth.

[0055] refer to Figure 2, the first cutting tooth 130 is a triangular tooth, the triangular tooth comprises a first columnar part 131, a triangular plane 132 is arranged on a central region of an end surface of the first columnar part 131, and three vertices of the triangular plane 132 are connected with a convex ridge 133 formed by two inclined surfaces, the convex ridge 133 is a working surface when the first cutting tooth 130 cuts a target rock stratum. When the convex ridge 133 is worn to the triangular plane 132, the triangular plane 132 forms a new working surface when the first cutting tooth 130 cuts the target rock stratum. The end surface of the first columnar part 131 can be polycrystalline diamond material.

[0056] With reference to Figure 3 The second cutting tooth 140 is a conical tooth, the conical tooth comprises a second columnar part 141 connected with a conical surface part 142, the conical surface part 142 has a conical angle of 60°-120°, a conical top of the conical surface part 142 can be arc-shaped, and an outer surface of the conical surface part 142 can be polycrystalline diamond material.

[0057] The first cutting tooth 130 comprises first impact-resistant teeth and first anti-abrasion teeth, the first impact-resistant teeth are arranged on the shoulder part 123 and the gauge part 124, and the first anti-abrasion teeth are arranged on the nose part 122 and the core part 121. The second cutting tooth 140 comprises second impact-resistant teeth and second anti-abrasion teeth, the second impact-resistant teeth are arranged on the shoulder part 123, and the second anti-abrasion teeth are arranged on the gauge part 124. By arranging the second impact-resistant teeth on the shoulder part 123 and adjusting the direction and height difference of the second impact-resistant teeth, the second impact-resistant teeth can actively contact the target rock stratum. In this way, on the one hand, the target rock stratum is broken and cracked by the second impact-resistant teeth, so as to achieve the purpose of pre-breaking the target rock stratum, and on the other hand, the drilling pressure and the torsional force are reduced, the whirl performance of the diamond bit 100 is improved, the damage of the first cutting tooth 130 and / or the second cutting tooth 140 caused by thermal wear and impact is reduced, and the service life of the diamond bit 100 is prolonged.

[0058] The first impact-resistant teeth and the first anti-abrasion teeth are obtained by acidizing the first original cutting tooth, the acidizing solution comprises a mixed solution of hydrochloric acid and nitric acid, the ratio of hydrochloric acid to nitric acid in the acidizing solution used for the first anti-abrasion teeth is different from the ratio of hydrochloric acid to nitric acid in the acidizing solution used for the first impact-resistant teeth. The first original cutting tooth is acidized in different acidizing solutions at different times and temperatures, the impact resistance of the first impact-resistant teeth after acidizing is improved by 100% or more compared with the first original cutting tooth, and the abrasion resistance of the first anti-abrasion teeth after acidizing is improved by 50% or more compared with the first original cutting tooth.

[0059] The second impact-resistant tooth and the second anti-abrasion tooth are obtained by acidizing the second original cutting tooth with an acidizing solution comprising a mixed solution of hydrochloric acid and nitric acid, the ratio of hydrochloric acid to nitric acid in the acidizing solution for the second anti-abrasion tooth is different from that in the acidizing solution for the second impact-resistant tooth. The second original cutting tooth is subjected to acidizing treatment in different acidizing solutions at different times and temperatures, the impact resistance of the second impact-resistant tooth after acidizing treatment is increased by 100% or more compared with the second original cutting tooth, and the anti-abrasion property of the second anti-abrasion tooth after acidizing treatment is increased by 50% or more compared with the second original cutting tooth.

[0060] With continued reference to Figure 1 , the gauge portion 124 is further provided with a gauge block 125, which can be a wear-resistant piece and is embedded or surfacing-welded on the gauge portion 124. The gauge block 125 can be made of hard alloy material, and the gauge block 125 is provided to prevent the diameter of the diamond drill bit 100 from being reduced (i.e., the diameter is reduced). The gauge block 125 can be further provided with gauge teeth, and the gauge teeth can be provided in two rows to increase the strength of the gauge portion 124. The two rows of gauge teeth are arranged at intervals on the gauge block 125, and the height of the gauge block 125 can be 8-9 cm to increase the contact area of the drill bit body 110 with the well wall during drilling, increase the stability of the diamond drill bit 100, and reduce the lateral force per unit area on the drill bit body 110, thereby reducing the wear rate of the gauge portion 124 and prolonging the service life of the diamond drill bit 100.

[0061] Specifically, the back rake angle of the gauge teeth can be 30-35° to further reduce the lateral impact force on the gauge teeth. The side of the gauge teeth away from the first end face is further provided with a back reaming tooth 160, as shown in Figure 1 The back reaming tooth 160 can prevent the drill string from being stuck during tripping and ensure the safety of the diamond drill bit 100. Exemplarily, the back reaming tooth 160 can have an outward convex surface.

[0062] The diamond drill bit 100 in the embodiment of the present application can determine the design parameters such as the exposed tooth height, the diameter of the first cutting tooth 130, the diameter of the second cutting tooth 140, the back rake angle of each cutting tooth, and the number of gauge teeth according to the use of the diamond drill bit 100, and generate the contour of the diamond drill bit 100 through the diamond drill bit 100 design software to obtain the spatial distribution of the first cutting tooth 130 and the second cutting tooth 140. Then, the force and cutting work distribution of the diamond drill bit 100 under different use parameters (such as rotation speed, drilling speed, etc.) are simulated according to the impact index and the abrasion index of the target rock formation to determine the type (impact-resistant tooth or anti-abrasion tooth), angle, and spacing of the first cutting tooth 130 and the second cutting tooth 140, thereby improving the impact resistance and abrasion resistance of the diamond drill bit 100.

[0063] Exemplarily, in the embodiment of the present application, the first cutting tooth 130 and the second cutting tooth 140 are arranged in two rows, and the front row tooth has a back rake angle of 15-25° with the cutting surface, and the rear row tooth has a back rake angle of 25°-35° with the cutting surface. The height of the rear row tooth can be greater than the height of the front row tooth, and the height difference is less than or equal to 2mm.

[0064] The diamond bit 100 provided by the embodiment of the present application comprises the first cutting tooth 130 and the second cutting tooth 140. The first cutting tooth 130 is used for breaking the target rock layer, and the second cutting tooth 140 is used for pre-breaking the target rock layer. The target rock layer is formed with an initial crack by the second cutting tooth 140, so as to reduce the drilling pressure and the torsional force when the first cutting tooth 130 breaks the target rock layer, improve the footage and the drilling speed of the diamond bit 100, and thus improve the drilling efficiency of the diamond bit 100. In addition, the first cutting tooth 130 comprises a first impact-resistant tooth and a first abrasion-resistant tooth, and the second cutting tooth 140 comprises a second impact-resistant tooth and a second abrasion-resistant tooth. The first impact-resistant tooth is arranged at the shoulder portion 123 and the gauge portion 124, the first abrasion-resistant tooth is arranged at the core portion 121 and the nose portion 122, the second impact-resistant tooth is arranged at the shoulder portion 123, and the second abrasion-resistant tooth is arranged at the gauge portion 124. Therefore, the arrangement of each tooth of the diamond bit 100 is matched with the force acting on the tooth, that is, the core portion 121 and the nose portion 122 with more serious abrasion in the diamond bit 100 are provided with the abrasion-resistant tooth, and the shoulder portion 123 with more serious impact is provided with the impact-resistant tooth. Therefore, the impact resistance and the abrasion resistance of the diamond bit 100 are improved, and thus the footage and the drilling speed of the diamond bit 100 are improved, so as to improve the drilling efficiency of the diamond bit 100.

[0065] Embodiment two

[0066] The embodiment of the present application further provides a manufacturing method of the diamond bit, which comprises the following steps.

[0067] In step S101, the first cutting tooth and the second cutting tooth are arranged in space.

[0068] The first cutting tooth is mainly used for shearing and breaking the target rock layer. The first cutting tooth cuts into the target rock layer and moves forward by overcoming the stress of the target rock layer, and the target rock layer is broken along the shearing direction of the first cutting tooth and generates plastic flow. The second cutting tooth is mainly used for pre-breaking the target rock layer. The second cutting tooth has a small contact area with the target rock layer and is subjected to concentrated force. The second cutting tooth cuts into the target rock layer earlier than the first cutting tooth, so that the target rock layer generates a breaking crack under the action of the contact stress, releases the stress of the target rock layer, and weakens the strength of the target rock layer, so as to facilitate the drilling of the first cutting tooth and improve the drilling efficiency. It can be understood that the second cutting tooth has an active anti-whirl ability, so as to reduce the whirl and the counter-torque of the diamond bit.

[0069] The first cutting tooth can be a triangular tooth, which includes a first columnar part, and a triangular plane is arranged on a central region of an end surface of the first columnar part. Three vertices of the triangular plane are connected with a convex ridge respectively, and the convex ridge is formed by two side slopes, and is a working surface when the first cutting tooth cuts a target rock formation. When the convex ridge is worn to the triangular plane, the triangular plane forms a new working surface when the first cutting tooth cuts the target rock formation. The end surface of the first columnar part can be polycrystalline diamond material.

[0070] The second cutting tooth can be a conical tooth, which includes a conical surface part and a second columnar part connected with a bottom surface of the conical surface part. A conical angle of the conical surface part can be 60°-120°, a conical top can be arc-shaped, and an outer surface of the conical surface part can be polycrystalline diamond material.

[0071] According to the use of the diamond bit, design parameters such as the tooth exposure height, the first cutting tooth diameter, the second cutting tooth diameter, the back rake angle of each cutting tooth, and the number of gauge teeth are determined, and a profile of the diamond bit is generated by a diamond bit design software. At this time, the spatial distribution of the first cutting tooth and the second cutting tooth is as shown in FIG. 2. Figure 4

[0072] In step S102, the grinding index and the impact index of the target rock formation are obtained, and the stress conditions of the first cutting tooth and the second cutting tooth under different drilling pressures and rotational speeds are simulated according to the grinding index and the impact index.

[0073] In some possible examples, the logging data is obtained by using natural gamma logging and acoustic logging, and the grinding index and the impact index of the target rock formation are calculated according to the logging data. The natural gamma logging refers to measuring the gamma ray intensity of the target rock formation, and obtaining the content of radioactive elements (such as potassium, thorium, uranium, etc.) of the target rock formation by spectral analysis, so as to obtain the logging data. The acoustic logging refers to measuring the acoustic characteristics (such as propagation speed) of sound waves in the target rock formation, so as to obtain the logging data.

[0074] Specifically, the gamma curve is obtained after the natural gamma logging, the gamma curve represents the gamma ray intensity changing with the depth, and the shale volume fraction of the target rock formation can be calculated according to the gamma curve. The shale volume fraction refers to the relative value of the volume content of mudstone, and the larger the shale volume fraction is, the higher the volume content of mudstone of the target rock formation is. The calculation formula of the shale volume fraction is as follows:

[0075] I GR = (GR-GR0) / (GR100-GR0) ;

[0076] I GR ​is the shale volume fraction, dimensionless, GR is the natural gamma ray reading value of the target layer (cps), GR100 is the natural gamma ray reading value of the pure sandstone layer (cps), and GR0 is the natural gamma ray reading value of the pure mudstone layer (cps). Generally, GR100 is 115, and GR0 is 15.

[0077] According to the formation volume model, such as the Larionov model, the shale index (V sh ) is calculated by the shale volume fraction (I GR ), and the calculation formula is as follows:

[0078]

[0079] According to the shale index, porosity, density, and formation fluid density, the sandstone content is calculated, and the specific calculation formula is as follows:

[0080] V SAND +V SHALE +V Other +CNC=1;

[0081] 2.65×V SAND +2.64×V SHALE +ρ other V Other +CNC×ρ fluid =ZDEN;

[0082] V SHALE =V sh ;

[0083] wherein V SAND is the volume proportion of sandstone in the rock, V SHALE is the volume proportion of mudstone in the rock, V Other is the volume proportion of other lithology in the rock, CNC is the pore volume proportion in the rock, ρ other is the average density of other lithology in the rock, ρ fluid is the pore fluid density in the rock, and ZDEN is the unit mass of the rock.

[0084] Continuing to normalize and logarithmize the above formula, the abrasion index of the target rock layer can be obtained, and the formula is as follows:

[0085] Abrasion Index=Normalize(V SAND / DT);

[0086] Abrasion Index is the abrasion index, and DT is the acoustic time difference of the rock

[0087] According to the Golubev empirical formula, the uniaxial compressive strength is calculated, and the calculation formula is as follows:

[0088]

[0089] wherein DT is the sonic travel time, unit is us / ft, and USD is the uniaxial compressive strength. When the diamond bit drills into the target rock formation with different uniaxial compressive strength, the cutting teeth on the shoulder of the diamond bit are prone to impact damage due to whirling. The change rate of the uniaxial compressive strength is related to the impact damage of the diamond bit.

[0090] The impact index of the target rock formation is calculated, and the calculation formula is:

[0091]

[0092] wherein UCS(i) is the uniaxial compressive strength value calculated at the ith depth, and ΔMD is the difference in well depth between the ith+1 depth and the ith depth.

[0093] In a possible example, the target rock formation is a gravel layer, the grinding index of the target rock formation is as shown in the left part of Figure 5 , and the impact index of the target rock formation is as shown in the right part of Figure 5 . The grinding index and the impact index of the target rock formation are loaded into a computer-aided engineering design software (for example, CAE), and the stress of the first cutting tooth and the second cutting tooth under different combinations of drilling parameters of drilling pressure and rotating speed is simulated.

[0094] It should be noted that there is no sequence between step S101 and step S102, that is, step S101 can be performed first, or step S102 can be performed first, or step S101 and step S102 can be performed simultaneously.

[0095] Step S103, according to the stress condition, the first cutting tooth selects the first anti-grinding tooth or the first anti-impact tooth, and the second cutting tooth selects the second anti-grinding tooth or the second anti-impact tooth.

[0096] According to the stress distribution of the obtained first cutting tooth or second cutting tooth, the first cutting tooth at different positions selects the first anti-grinding tooth or the first anti-impact tooth, and the second cutting tooth selects the second anti-grinding tooth or the second anti-impact tooth, so that the performance of the first cutting tooth or the second cutting tooth matches the stress, thereby improving the impact resistance and the grinding resistance of the diamond bit, and further improving the footage and the drilling speed of the diamond bit, thereby improving the drilling efficiency of the diamond bit.

[0097] For example, refer to Figure 6In some possible examples, among the 1st to 47th teeth numbered sequentially from the heart of the blade wing to the gage portion, the 1st to 14th teeth are anti-abrasion teeth, and the 15th to 47th teeth are anti-impact teeth. It can be understood that the 1st to 14th teeth are the first cutting teeth or the second cutting teeth which have been determined according to the previous steps and will not be changed, and the present step is used to determine the types (anti-abrasion or anti-impact) of the first cutting teeth and the second cutting teeth.

[0098] It should be noted that the manufacturing method of the diamond drill bit in the embodiment of the present application can further include the following steps:

[0099] Step a: obtaining a plurality of first original cutting teeth and a plurality of second original cutting teeth, and the diamond layer of each first original cutting tooth and each second original cutting tooth is formed into a required shape by electric spark machining.

[0100] The first original cutting tooth can be a triangular pyramid tooth, which includes a first columnar portion, and a triangular plane is arranged on the central region of the end face of the first columnar portion, and three vertices of the triangular plane are connected with a convex ridge respectively, the convex ridge is formed by two side slopes, and the end face of the first columnar portion is made of polycrystalline diamond material.

[0101] When manufacturing the first original cutting tooth, the planar composite sheet is sintered into a required shape under high temperature and high pressure conditions, and centerless grinding is performed to make the outer diameter reach the requirement, and then polishing is performed on the diamond grinding disc to make the diamond layer form a plane, and then the diamond layer is machined into a required triangular plane by electric spark machining. In this way, the convex ridge of the top surface and the slope for forming the convex ridge are formed at one time during sintering, thereby reducing the error caused by the shrinkage rate of the diamond layer during sintering. In addition, the machining precision of electric spark machining is easy to control, and the damage to the diamond layer during machining can be reduced, so that the first original cutting tooth has the characteristics of high machining precision, low cost and small damage.

[0102] The second original cutting tooth can be a conical tooth, which includes a conical surface portion and a second columnar portion connected with the bottom surface of the conical surface portion. The conical angle of the conical surface portion can be 60°-120°, the conical top can be arc-shaped, and the conical surface portion can be made of polycrystalline diamond material. The manufacturing process of the second original cutting tooth is referred to the manufacturing process of the first original cutting tooth, which will not be described here.

[0103] Step b: sealing the part of the non-diamond layer of each first original cutting tooth and each second original cutting tooth.

[0104] For example, the part of the non-diamond layer of each first original cutting tooth and each second original cutting tooth is sealed by a Teflon sealing member, and the diamond layer of each first original cutting tooth and each second original cutting tooth is exposed.

[0105] Step c: different acidizing treatments are performed on the exposed diamond layer of each first original cutting tooth and each second original cutting tooth; wherein, part of the first original cutting teeth form first anti-abrasion teeth, part of the first original cutting teeth form first anti-impact teeth, part of the second original cutting teeth form second anti-abrasion teeth, and part of the second original cutting teeth form second anti-impact teeth.

[0106] The first original cutting teeth and the second original cutting teeth are placed in an acidizing solution, and different acidizing treatments are performed on the exposed diamond layer of each first original cutting tooth and each second original cutting tooth. The acidizing solution includes a mixed solution of hydrochloric acid and nitric acid, and the acidizing solution includes multiple acidizing solutions with different ratios of hydrochloric acid and nitric acid.

[0107] Specifically, the first original cutting teeth are acidized in different acidizing solutions for different times and temperatures, and the impact resistance of the first anti-impact teeth after acidizing treatment is improved by 100% or more compared with the first original cutting teeth, and the abrasion resistance of the first anti-abrasion teeth after acidizing treatment is improved by 50% or more compared with the first original cutting teeth.

[0108] The second original cutting teeth are acidized in different acidizing solutions for different times and temperatures, and the impact resistance of the second anti-impact teeth after acidizing treatment is improved by 100% or more compared with the second original cutting teeth, and the abrasion resistance of the second anti-abrasion teeth after acidizing treatment is improved by 50% or more compared with the second original cutting teeth.

[0109] The manufacturing method of the diamond bit provided by the embodiment of the present application, according to the abrasion index and impact index of the target rock stratum, simulates the stress conditions of the first cutting teeth and the second cutting teeth under different working conditions, and according to the stress conditions, determines that the first cutting teeth select the first anti-abrasion teeth or the first anti-impact teeth, and the second cutting teeth select the second anti-abrasion teeth or the second anti-impact teeth, so that the arrangement of each anti-abrasion tooth and each anti-impact tooth is matched with the stress, thereby improving the impact resistance and abrasion resistance of the diamond bit, and further improving the footage and drilling speed of the diamond bit, thereby improving the drilling efficiency of the diamond bit.

[0110] Each embodiment or implementation in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between each embodiment can be referred to each other.

[0111] Those skilled in the art should understand that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like in the disclosure of the present application are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the systems or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation of the present application.

[0112] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means 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 application. In the present application, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0113] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A diamond drill bit, characterized in that, The drill bit comprises a drill bit body, a blade arranged on the drill bit body, and a first cutting tooth and a second cutting tooth arranged on the blade, the blade is arranged on a side wall of the drill bit body and extends to a first end surface of the drill bit body, and the blade comprises, in sequence, a core portion, a nose portion, a shoulder portion and a gauge portion in a direction away from the first end surface; The second cutting tooth is used for pre-breaking a target rock formation, the first cutting tooth comprises a first impact-resistant tooth and a first abrasion-resistant tooth, the first impact-resistant tooth is arranged on the shoulder portion and the gauge portion, and the first abrasion-resistant tooth is arranged on the core portion and the nose portion; the second cutting tooth comprises a second impact-resistant tooth and a second abrasion-resistant tooth, the second impact-resistant tooth is arranged on the shoulder portion, and the second abrasion-resistant tooth is arranged on the gauge portion; The first impact-resistant tooth and the first abrasion-resistant tooth are obtained by acidizing the first cutting tooth, the acidizing solution comprises a mixed solution of hydrochloric acid and nitric acid, and the ratio of hydrochloric acid to nitric acid in the acidizing solution used for the first abrasion-resistant tooth is different from the ratio of hydrochloric acid to nitric acid in the acidizing solution used for the first impact-resistant tooth; The second impact-resistant tooth and the second abrasion-resistant tooth are obtained by acidizing the second cutting tooth, the acidizing solution comprises a mixed solution of hydrochloric acid and nitric acid, and the ratio of hydrochloric acid to nitric acid in the acidizing solution used for the second abrasion-resistant tooth is different from the ratio of hydrochloric acid to nitric acid in the acidizing solution used for the second impact-resistant tooth; The blade is provided with double rows of teeth, and the side of the blade away from the first end surface is further provided with a back gage tooth; The first cutting tooth is a triangular prism tooth, the first cylindrical portion is provided with a triangular plane in the central region of the end surface, and the three vertices of the triangular plane are connected to a convex ridge, respectively; The second cutting tooth is a conical tooth, the conical tooth comprises a conical surface portion and a second cylindrical portion connected to the bottom surface of the conical surface portion. The conical angle of the conical surface portion is 60°-120°.

2. The diamond drill bit of claim 1, wherein, The method comprises the following steps:

3. A method of manufacturing a diamond bit as claimed in claim 1 or 2, characterized in that, Spatially arranging the first cutting tooth and the second cutting tooth; Obtaining an abrasion index and an impact index of a target rock formation, and simulating the stress conditions of the first cutting tooth and the second cutting tooth under different drilling pressures and rotational speeds according to the abrasion index and the impact index; According to the stress conditions, determining that the first cutting tooth selects a first impact-resistant tooth or a first abrasion-resistant tooth, and the second cutting tooth selects a second impact-resistant tooth or a second abrasion-resistant tooth. When obtaining the abrasion index and the impact index of the target rock formation, logging data is obtained by using natural gamma logging and acoustic logging, and the abrasion index and the impact index of the target rock formation are calculated according to the logging data.

4. The method of manufacturing a diamond drill bit according to claim 3, wherein, The method further comprises the following steps:

5. The method of manufacturing a diamond drill bit according to claim 3 or 4, characterized in that, Obtaining a plurality of first cutting teeth and a plurality of second cutting teeth, and electrically spark machining the diamond layer of each first cutting tooth and each second cutting tooth into a required shape; Sealing the non-diamond layer of each first cutting tooth and each second cutting tooth. ​ The diamond layer exposed to each of the first cutting teeth and each of the second cutting teeth is subjected to different acidizing treatments; wherein some of the first cutting teeth form first anti-abrasion teeth, some of the first cutting teeth form first anti-impact teeth, some of the second cutting teeth form second anti-abrasion teeth, and some of the second cutting teeth form second anti-impact teeth.

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