Continuous rear row of teeth PDC bit

Abstract

This invention relates to the technical field of drilling equipment for oil and gas, geothermal, and geophysical exploration, and is a continuous rear-row PDC drill bit, comprising a drill bit body and several cutter wings disposed on the drill bit body. The invention features a reasonable and compact structure. The front end of the secondary cutting teeth is fixedly connected to the rear end of the adjacent main cutting teeth. Adjacent secondary cutting teeth are sequentially fixed together from front to back, increasing tooth density while reducing cutter wing width, ensuring sufficient flow channel area, and leaving ample space for the drill bit's water channel configuration. The rear secondary cutting teeth enhance the support strength of the front secondary or main cutting teeth, improving the reliability and service life of the drill bit's cutting teeth. When the front row of cutting teeth is damaged or worn, the rear row of cutting teeth can directly serve as a replacement and auxiliary to the front row, thereby enhancing the drill bit's continuous drilling capability, improving rock-breaking drilling efficiency, reliability, and service life.

Description

Technical Field

[0001] This invention relates to the field of drilling equipment technology for oil and gas, geothermal, and geophysical exploration, and is a continuous rear-row tooth PDC drill bit. Background Technology

[0002] Drill bit performance directly affects drilling efficiency, quality, cost, and even safety. Although small, drill bits are crucial tools for accelerating drilling and reducing costs. PDC (Polycrystalline Diamond Compact Bit) drill bits, playing a vital role in this process, have become the primary rock-breaking tool, gradually replacing roller cone bits. Nearly 80% of drilling footage is achieved using PDC drill bits, which have already established a dominant position in the oil drill bit market.

[0003] Although PDC drill bits have many advantages and are widely used, they are less wear-resistant in hard formations compared to other drill bits. To improve the wear resistance of PDC drill bits, the tooth density is generally increased to extend their service life. Common methods include using double-row, triple-row, or other multi-row tooth structures.

[0004] Existing PDC drill bits with multi-row tooth arrangement often have a certain spacing between the front and rear rows of teeth to ensure the bonding strength of the front row. A body of a certain thickness is left between the front and rear rows to support the front row. However, if the spacing is too small, the strength is often insufficient; if the spacing is too large, it occupies a lot of space, and tooth arrangement becomes difficult due to drill bit size limitations. Using multiple tooth rows results in excessively wide cutter wings and narrow flow channels, restricting the bottomhole flow field and hydraulic structure. This significantly affects bottomhole cleaning and rock-carrying performance during drilling, increases the risk of mud buildup, and impacts drilling efficiency and service life, especially in deep well drilling where formation hardness is high, making the problems even more pronounced for drill bits with smaller wellbore sizes. Summary of the Invention

[0005] This invention provides a continuous rear-row tooth PDC drill bit that overcomes the shortcomings of the prior art. It can effectively solve the problems of tooth placement difficulties, significant impact on bottom hole cleaning and rock carrying performance during drilling, high risk of drill bit mud packing, and reduced drilling efficiency and service life of existing multi-row tooth structure PDC drill bits.

[0006] The technical solution of the present invention is achieved through the following measures: a continuous rear-row tooth PDC drill bit, comprising a drill bit body and a plurality of cutter wings disposed on the drill bit body, wherein a plurality of main cutting teeth are spaced apart on the outer side of each cutter wing, wherein at least one cutter wing is also provided with a tooth group on the outer side, the tooth group comprising a plurality of continuous teeth spaced apart on the outer side of the cutter wing, each continuous tooth comprising at least one secondary cutting tooth disposed on the cutter wing along the central axis of the main cutting tooth and away from the cutting end face of the main cutting tooth, along the drilling rotation direction of the drill bit body, the front end of each foremost secondary cutting tooth is fixedly connected to the rear end of the main cutting tooth adjacent to it, and two adjacent secondary cutting teeth are fixedly connected together sequentially from front to back.

[0007] The following are further optimizations and / or improvements to the above-mentioned technical solution:

[0008] Each of the aforementioned consecutive teeth may include at least two secondary cutting teeth.

[0009] The rake angle of the main cutting tooth and the rake angle of the secondary cutting tooth can be the same and range from 10 to 27°.

[0010] The central axis of the main cutting tooth and the central axes of all the secondary cutting teeth behind the main cutting tooth can be collinear. The radius of the main cutting tooth and the radius of all the secondary cutting teeth increase sequentially from front to back. Alternatively, the central axis of the main cutting tooth and the central axes of all the secondary cutting teeth behind the main cutting tooth can be set parallel to each other, and two adjacent central axes can be set alternately from front to back and from bottom to top. The radius of the main cutting tooth and the radius of all the secondary cutting teeth decrease sequentially from front to back.

[0011] The first exposure height of the front end of the main cutting tooth relative to the blade wing can be less than the second exposure height of the front end of the foremost secondary cutting tooth relative to the blade wing, and the difference between the first exposure height and the second exposure height is not greater than one-fifth of the radius of the main cutting tooth. Between two adjacent secondary cutting teeth, the third exposure height of the front secondary cutting tooth relative to the blade wing is less than the fourth exposure height of the rear secondary cutting tooth relative to the blade wing, and the difference between the third exposure height and the fourth exposure height is not greater than one-fifth of the radius of the front secondary cutting tooth.

[0012] The fifth protrusion height of the foremost secondary cutting tooth relative to the rear end of the main cutting tooth may not be less than one-quarter of the radius of the foremost secondary cutting tooth. Between two adjacent secondary cutting teeth, the sixth protrusion height of the rear secondary cutting tooth relative to the rear end of the foremost secondary cutting tooth may not be less than one-quarter of the radius of the rear secondary cutting tooth.

[0013] The highest point of the front end of the main cutting tooth can be 1 to 3 mm higher than the highest point of the front end of the secondary cutting tooth. Between two adjacent secondary cutting teeth, the highest point of the front secondary cutting tooth is 1 to 3 mm higher than the highest point of the rear secondary cutting tooth.

[0014] The largest circle formed by the main cutting teeth on the blade can be the cutting circle, and the projection of the secondary cutting teeth onto the cutting circle is located in the region between one-third and one-half of the diameter of the cutting circle.

[0015] The present invention has a reasonable and compact structure. The front end of the secondary cutting tooth is fixedly connected to the rear end of the main cutting tooth located adjacent to it. The two adjacent secondary cutting teeth are fixedly connected together from front to back. While increasing the tooth density, the blade width is reduced, ensuring the flow channel area and leaving enough space for the water channel setting of the drill bit. The rear secondary cutting tooth can enhance the support strength of the front secondary cutting tooth or main cutting tooth, which is conducive to improving the tooth fixing reliability and service life of the drill bit cutting teeth. After the front row of cutting teeth is damaged or worn, the rear row of cutting teeth can be directly used as a substitute to supplement and assist the front row of teeth, thereby enhancing the continuous drilling capability of the drill bit, improving the rock breaking drilling efficiency, reliability and service life of the drill bit, and enhancing the continuous drilling capability of the drill bit. Attached Figure Description

[0016] Appendix Figure 1 This is a schematic diagram of the main structure of Embodiment 1.

[0017] Appendix Figure 2 For the appendix Figure 1 A top-view structural diagram.

[0018] Appendix Figure 3 This is a three-dimensional structural diagram of Example 1.

[0019] Appendix Figure 4 This is a partial cross-sectional view of the structure in Embodiment 2, where the central axis of the secondary cutting tooth and the central axis of the main cutting tooth are arranged parallel to each other.

[0020] Appendix Figure 5 This is a partial cross-sectional view of the secondary cutting teeth and the main cutting teeth arranged coaxially in Example 2.

[0021] The codes in the attached diagram are as follows: 1 is the drill bit body, 2 is the cutter blade, 3 is the main cutting tooth, 4 is the secondary cutting tooth, α is the rake angle of the main cutting tooth, β is the rake angle of the secondary cutting tooth, r1 is the radius of the main cutting tooth, r2 is the radius of the secondary cutting tooth, h1 is the first exposure height, h2 is the second exposure height, h3 is the third exposure height, h4 is the fourth exposure height, h5 is the fifth exposure height, and h6 is the sixth exposure height. Detailed Implementation

[0022] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0023] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0024] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0025] Example 1: As shown in the attached document Figure 1 , 2 As shown in Figure 3, the continuous rear-row PDC drill bit includes a drill bit body 1 and several cutter wings 2 disposed on the drill bit body 1. Several main cutting teeth 3 are spaced apart on the outer side of each cutter wing 2. At least one cutter wing 2 is also provided with a tooth group on its outer side. The tooth group includes several continuous teeth spaced apart on the cutter wing 2. Each continuous tooth includes at least one secondary cutting tooth 4 disposed on the outer side of the cutter wing 2 along the central axis of the main cutting tooth 3 and away from the cutting end face of the main cutting tooth 3. Along the drilling rotation direction of the drill bit body 1, the front end of each foremost secondary cutting tooth 4 is fixedly connected to the rear end of the main cutting tooth 3 adjacent to it. Two adjacent secondary cutting teeth 4 are fixedly connected together from front to back.

[0026] During use, the front end of each foremost secondary cutting tooth 4 is fixedly connected to the rear end of the adjacent primary cutting tooth 3. Adjacent secondary cutting teeth 4 are sequentially fixedly connected from front to back. This compact tooth arrangement ensures that the secondary cutting teeth 4 and primary cutting teeth 3 on each blade 2 form a continuous overlapping arrangement, with no wasted space between the front and rear rows. This maximizes the use of drill bit space, increases tooth density while reducing the width of the blade 2, ensuring sufficient flow channel area and leaving ample space for the drill bit's water channel design. The rear secondary cutting teeth 4 can enhance the performance of the front secondary cutting teeth 4 or... The increased support strength of the main cutting teeth 3 helps improve the reliability and service life of the drill bit's cutting teeth. The front row of cutting teeth of the blade 2 can also directly protect the rear row of cutting teeth. After the front row of cutting teeth is damaged or worn, the rear row of cutting teeth can directly serve as a substitute to supplement and assist the front row of teeth, thereby enhancing the drill bit's continuous drilling capability. The invention has a reasonable and compact structure, which can improve the drill bit's tooth placement freedom, save tooth placement space, optimize the drill bit's hydraulic structure, improve the drill bit's rock-breaking drilling efficiency, improve the tooth placement strength, reliability and service life of the drill bit's cutting teeth, and enhance the drill bit's continuous drilling capability.

[0027] The above-mentioned continuous rear-row PDC drill bit can be further optimized and / or improved according to actual needs:

[0028] Example 2: As shown in the attached document Figure 4 , 5 As shown, each continuous tooth includes at least two secondary cutting teeth 4.

[0029] Depending on the requirements, each continuous tooth can include four to six secondary cutting teeth 4. During use, this configuration can improve the drilling efficiency of the drill bit in breaking rock and extend its service life, reduce the impact of well bottom cleaning and rock carrying performance during drilling, and reduce the risk of drill bit mud packing. At the same time, it facilitates the setting of secondary cutting teeth 4 and reduces manufacturing costs.

[0030] As attached Figure 4 , 5 As shown, the rake angle α of the main cutting tooth and the rake angle β of the secondary cutting tooth are the same and range from 10 to 27°.

[0031] The rake angle refers to the angle between the cutting surface of the PDC tooth and the normal to the drill bit cutting profile at the radial position point of the PDC tooth. Figure 4 or Figure 5 The vertical centerline on the left is the normal to the cutting profile of the front row of teeth; Figure 4 or Figure 5 The angle between the vertical centerline on the right and the normal to the cutting profile of the rear teeth. During use, this improves the drill bit's overall formation penetration and rock-breaking efficiency.

[0032] As attached Figure 4 , 5 As shown, the central axis of the main cutting tooth 3 and the central axes of all the secondary cutting teeth 4 behind the main cutting tooth 3 are collinear. The radius of the main cutting tooth 3 and the radius of all the secondary cutting teeth 4 increase sequentially from front to back. Alternatively, the central axis of the main cutting tooth 3 and the central axes of all the secondary cutting teeth 4 behind the main cutting tooth 3 are set in parallel, and two adjacent central axes are set alternately from front to back and from bottom to top. The radius of the main cutting tooth 3 and the radius of all the secondary cutting teeth 4 decrease sequentially from front to back.

[0033] During use, this setting can reduce the difficulty of tooth placement for the secondary cutting tooth 4.

[0034] As attached Figure 4 , 5 As shown, the first exposed height h1 of the front end of the main cutting tooth 3 relative to the blade wing 2 is less than the second exposed height h2 of the front end of the foremost secondary cutting tooth 4 relative to the blade wing 2, and the difference between the first exposed height h1 and the second exposed height h2 is not greater than one-fifth of the radius r1 of the main cutting tooth. Between two adjacent secondary cutting teeth 4, the third exposed height h3 of the front secondary cutting tooth 4 relative to the blade wing 2 is less than the fourth exposed height h4 of the rear secondary cutting tooth 4 relative to the blade wing 2, and the difference between the third exposed height h3 and the fourth exposed height h4 is not greater than one-fifth of the radius r2 of the front secondary cutting tooth.

[0035] The first exposed height h1 refers to the distance between the highest point of the front face of the main cutting tooth 3 and the outer side of the blade 2. The second exposed height h2 is the same as the second exposed height h3 (when there are two secondary cutting teeth), referring to the distance between the highest point of the front face of the foremost secondary cutting tooth 4 and the outer side of the blade 2. The fourth exposed height h4 refers to the distance between the highest point of the front face of the rear secondary cutting tooth 4 and the outer side of the blade 2. This configuration improves the strength of the cutting teeth, increases the drill bit's rock-breaking drilling efficiency, and extends its service life.

[0036] As attached Figure 4 , 5 As shown, the fifth exposure height h5 of the front end of the foremost secondary cutting tooth 4 relative to the rear end of the main cutting tooth 3 is not less than one-quarter of the radius r2 of the foremost secondary cutting tooth. Between two adjacent secondary cutting teeth 4, the sixth exposure height h6 of the front end of the rear secondary cutting tooth 4 relative to the rear end of the front secondary cutting tooth 4 is not less than one-quarter of the radius r2 of the rear secondary cutting tooth.

[0037] The fifth exposed height h5 refers to the distance between the highest point of the rear end face of the main cutting tooth 3 and the highest point of the front end face of the foremost secondary cutting tooth 4. The sixth exposed height h6 refers to the distance between the highest point of the front end face of the rear secondary cutting tooth 4 and the highest point of the rear end face of the front secondary cutting tooth 4. During use, the front row of cutting teeth on the cutter wing 2 can directly protect the rear row of cutting teeth, enhancing the drill bit's continuous drilling capability.

[0038] As attached Figure 4 , 5 As shown, the highest point of the front end of the main cutting tooth 3 is 1 to 3 mm higher than the highest point of the front end of the foremost secondary cutting tooth 4. Between two adjacent secondary cutting teeth 4, the highest point of the front end of the secondary cutting tooth 4 is 1 to 3 mm higher than the highest point of the front end of the rear secondary cutting tooth 4.

[0039] During use, this configuration allows the front row of cutting teeth on the cutter wing 2 to directly protect the rear row of cutting teeth. If the front row of cutting teeth is damaged or worn, the rear row of cutting teeth can directly serve as a substitute to supplement and assist the front row of teeth, thereby enhancing the drill bit's continuous drilling capability.

[0040] As attached Figure 4 , 5 As shown, the largest circle formed by the main cutting teeth 3 on the blade 2 is the cutting circle, and the projection of the secondary cutting teeth 4 onto the cutting circle is located in the region between one-third and one-half of the diameter of the cutting circle.

[0041] During use, this configuration can improve the drill bit's adaptability in special and complex formations, enhance its ability to penetrate different formations, and maximize the advantages of the invention.

[0042] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A continuous rear-row PDC drill bit, comprising a drill bit body and a plurality of cutter wings disposed on the drill bit body, wherein a plurality of main cutting teeth are spaced apart on the outer side of each cutter wing, characterized in that... At least one of the cutter wings is also provided with a tooth group on the outer side. The tooth group includes several continuous teeth spaced apart on the outer side of the cutter wings. Each continuous tooth includes at least one secondary cutting tooth located on the cutter wing along the central axis of the main cutting tooth and away from the cutting end face of the main cutting tooth. Along the drilling rotation direction of the drill body, the front end of each foremost secondary cutting tooth is fixedly connected to the rear end of the main cutting tooth at its adjacent position. Two adjacent secondary cutting teeth are fixedly connected together from front to back. Each continuous tooth includes at least two secondary cutting teeth; the rake angle of the primary cutting teeth and the rake angle of the secondary cutting teeth are the same and are between 10 and 27°; The central axis of the main cutting tooth and the central axes of all the secondary cutting teeth behind the main cutting tooth are collinear. The radius of the main cutting tooth and the radius of all the secondary cutting teeth increase sequentially from front to back. Alternatively, the central axis of the main cutting tooth and the central axes of all the secondary cutting teeth behind the main cutting tooth are set in parallel, and two adjacent central axes are set alternately from front to back and from bottom to top. The radius of the main cutting tooth and the radius of all the secondary cutting teeth decrease sequentially from front to back. The first exposure height of the front end of the main cutting tooth relative to the blade wing is less than the second exposure height of the front end of the foremost secondary cutting tooth relative to the blade wing, and the difference between the first exposure height and the second exposure height is not greater than one-fifth of the radius of the main cutting tooth. Between two adjacent secondary cutting teeth, the third exposure height of the front secondary cutting tooth relative to the blade wing is less than the fourth exposure height of the rear secondary cutting tooth relative to the blade wing, and the difference between the third exposure height and the fourth exposure height is not greater than one-fifth of the radius of the front secondary cutting tooth.

2. The continuous rear-row tooth PDC drill bit according to claim 1, characterized in that... The fifth protrusion height of the foremost secondary cutting tooth relative to the rear end of the main cutting tooth is not less than one-quarter of the radius of the foremost secondary cutting tooth. Between two adjacent secondary cutting teeth, the sixth protrusion height of the rear secondary cutting tooth relative to the rear end of the foremost secondary cutting tooth is not less than one-quarter of the radius of the rear secondary cutting tooth.

3. The continuous rear-row PDC drill bit according to claim 1 or 2, characterized in that... The highest point of the front end of the main cutting tooth is 1 to 3 mm higher than the highest point of the front end of the foremost secondary cutting tooth. Between two adjacent secondary cutting teeth, the highest point of the front secondary cutting tooth is 1 to 3 mm higher than the highest point of the rear secondary cutting tooth.

4. The continuous rear-row PDC drill bit according to claim 1 or 2, characterized in that... The largest circle formed by the main cutting teeth on the blade is the cutting circle, and the projection of the secondary cutting teeth onto the cutting circle is located in the region between one-third and one-half of the diameter of the cutting circle.

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