Drill bit with dual functions of cutting and grinding and application

Abstract

The invention discloses a drill bit with dual functions of cutting and grinding and application, and relates to the technical field of rock breaking in oil drilling, and the drill bit is characterized in that a plurality of drill bit blades are arranged on a drill bit cylinder; a plurality of rows of rock breaking elements are arranged on each drill bit blade, and each row of rock breaking elements is composed of a plurality of PDC compacts or a plurality of diamond-impregnated compacts; the height of the PDC compact on the drill bit blade is larger than the height of the impregnated diamond compact on the drill bit blade. Through the synergistic effect of cutting rock breaking of the PDC compact and grinding rock breaking of the impregnated diamond compact, after the PDC compact is abraded, diamond particles exposed out of the impregnated diamond compact grind the stratum, weaken the rock strength and assist the PDC compact to continuously penetrate into the rock, so that the rock breaking efficiency of the drill bit is improved, the service life of the drill bit is prolonged, and the drill bit is suitable for large-scale popularization and application. And the purposes of reducing the tripping times, reducing the drilling cycle and reducing the drilling cost are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling and rock breaking, and in particular to a drill bit with dual functions of cutting and grinding and its application. Background Art

[0002] In recent years, with the increase in exploration and development efforts at home and abroad, shallow and easily developed oil and gas resources are becoming less and less. Seeking oil and gas resources in deep strata and complex geological conditions is gradually becoming an important task in current marine and land exploration and development. In the drilling of deep and ultra-deep wells, drilling often encounters formations with strong abrasiveness, high hardness and poor drillability, such as quartz sandstone, siliceous dolomite and igneous rock. Existing rock breaking tools and drilling methods generally have problems such as slow drilling speed, short drill bit life, long drilling cycle and high cost.

[0003] In response to the above-mentioned difficult problems, domestic and foreign experts, scholars and engineers have carried out a lot of research work and believe that although PDC drill bits have high rock breaking efficiency in soft to medium-hard formations, they have significant problems such as fast wear of cutting teeth and low mechanical drilling speed in highly abrasive hard formations such as igneous rocks. In order to improve the adaptability of PDC drill bits in highly abrasive hard formations, extensive research and optimization have been carried out in terms of the type of cutting teeth and the arrangement of teeth on the drill bit, but the problems of excessive wear of PDC composite pieces and significant decrease in mechanical drilling speed cannot be solved. As a commonly used rock-breaking tool for hard formations, impregnated drill bits have also been optimized and improved by domestic and foreign experts and scholars, but due to the rock-breaking mechanism of impregnated diamond drill bits and the size of diamond particles, even with high-speed turbine drills, the rock-breaking efficiency of impregnated diamond drill bits cannot be significantly improved.

[0004] Considering that many drill bits with a single rock-breaking method cannot effectively improve the mechanical drilling speed and service life of highly abrasive hard formations, how to solve the problems of slow drilling speed and short drill bit life in highly abrasive hard formations has become a technical problem that urgently needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a drill bit with dual functions of cutting and grinding and its application. The drill bit solves the problem of rapid wear of conventional drill bit cutting teeth through the synergistic effect of cutting and grinding, while improving the drill bit's footage and rock breaking efficiency, reducing the number of drilling trips, and reducing the drilling cycle and cost.

[0006] To achieve the above object, the present invention provides a drill bit with dual functions of cutting and grinding, the drill bit comprising: a drill bit cylinder, a plurality of PDC composite sheets, a plurality of impregnated diamond composite sheets, and a plurality of drill bit blades;

[0007] Among them, a plurality of drill blades are arranged on the drill bit cylinder; a plurality of rows of rock breaking elements are arranged on each of the drill blades, and each row of the rock breaking elements is composed of a plurality of the PDC composite sheets or a plurality of the impregnated diamond composite sheets; the height of the PDC composite sheet on the drill blade is greater than the height of the impregnated diamond composite sheet on the drill blade.

[0008] Optionally, the height of the PDC composite piece on the drill blade is 0.5-2.0 mm higher than the height of the diamond-impregnated composite piece on the drill blade.

[0009] Optionally, arranging multiple rows of rock breaking elements on each of the drill blades includes: arranging two or three rows of rock breaking elements on each of the drill blades;

[0010] Among them, the first row of rock-breaking elements consists of multiple PDC composite pieces, and the second row of rock-breaking elements consists of multiple diamond-impregnated composite pieces; or, the first row of rock-breaking elements consists of multiple PDC composite pieces, the second row of rock-breaking elements consists of multiple diamond-impregnated composite pieces, and the third row of rock-breaking elements consists of multiple PDC composite pieces.

[0011] Optionally, each of the diamond-impregnated composite sheets in the second row is arranged in the same track behind each of the PDC composite sheets in the first row, and each of the PDC composite sheets in the third row is arranged in the same track or in a different track behind each of the diamond-impregnated composite sheets in the second row.

[0012] Optionally, the back tilt angle of the PDC composite sheet is 10-20°, and the back tilt angle of the diamond-impregnated composite sheet is 0°.

[0013] Optionally, the number of the drill blades is 6-8.

[0014] Optionally, the plurality of drill blades include a plurality of short wings and long wings that are spaced apart.

[0015] Optionally, the impregnated diamond composite sheet is obtained by sintering natural or artificial diamond particles, tungsten carbide or cast carbide, metal and non-metal powders together.

[0016] Optionally, the drill bit further includes: a plurality of mud channels formed between any two of the drill bit blades.

[0017] The present invention also provides an application of a drill bit, wherein the drill bit is applied to drilling in a hard formation with strong abrasiveness.

[0018] Technical effects and advantages of the present invention:

[0019] The present invention realizes the synergistic effect of rock cutting by PDC composite pieces and rock grinding by diamond impregnated composite pieces. After the PDC composite pieces are worn, the diamond particles exposed by the diamond impregnated composite pieces grind the strata to weaken the rock strength and assist the PDC composite pieces to continuously eat into the rock, thereby improving the rock breaking efficiency of the drill bit, extending the service life of the drill bit, and achieving the purpose of reducing the number of trips and drilling cycles and reducing the drilling cycle and cost.

[0020] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A top view of a drill bit having dual functions of cutting and grinding;

[0022] Figure 2 It is a front view of a drill bit having dual functions of cutting and grinding;

[0023] Figure numerals: 1-drill bit cylinder, 2-PDC composite piece, 3-diamond impregnated composite piece, 4-drill bit blade, 5-mud channel, 6-water eye positioning rod. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0026] In order to solve the shortcomings of the prior art, the present invention discloses a drill bit with dual functions of cutting and grinding, such as Figure 1 and 2 The drill bit comprises: a drill bit column 1, a plurality of PDC composite sheets 2, a plurality of diamond-impregnated composite sheets 3, and a plurality of drill bit blades 4.

[0027] Specifically, a plurality of drill blades 4 are arranged on the upper part of the drill column 1. Since the drill blades 4 are arranged with double rows of teeth or three rows of teeth, the thickness of the drill blades 4 is relatively large, so the number should not be too large. Preferably, 6 to 8 drill blades 4 are arranged on the drill column 1, and the drill blades 4 include a plurality of short wings and a plurality of long wings arranged at intervals.

[0028] Specifically, multiple rows of rock-breaking elements are arranged on each of the drill blades 4, and each row of the rock-breaking elements is composed of multiple PDC composite pieces 2 or multiple impregnated diamond composite pieces 3. Preferably, two or three rows of rock-breaking elements can be arranged on the same drill blade 4, the first row of rock-breaking elements is PDC composite pieces 2, the second row of rock-breaking elements is impregnated diamond composite pieces 3, and if a third row of rock-breaking elements is required, it is PDC composite pieces 2. Among them, each impregnated diamond composite piece 3 in the second row is arranged in the same track behind the corresponding first row of PDC composite pieces 2, and if a third row of rock-breaking elements is required, each PDC composite piece 2 in the third row is arranged in the same track or out of track behind the corresponding second row of impregnated diamond composite pieces 3.

[0029] Specifically, the height of the PDC composite piece 2 on the drill blade 4 is greater than the height of the impregnated diamond composite piece 3 on the drill blade 4. Preferably, the PDC composite piece 2 is 0.5 to 2.0 mm higher than the initial working surface of the impregnated diamond composite piece 3, that is, there is a height difference. Among them, indoor and field tests show that the PDC composite piece shears and breaks rocks at a back rake angle of 10 to 20°, and the drill bit has the highest rock breaking efficiency. The impregnated diamond composite piece is used for grinding formations, and the back rake angle of 0° can exert the greatest grinding effect.

[0030] At the beginning of operation, the PDC composite piece 2 contacts the formation before the diamond-impregnated composite piece 3 and participates in the work of cutting the formation. At the later stage of operation, when the PDC composite piece 2 is worn, the worn PDC composite piece 2 and the diamond-impregnated composite piece 3 work together to cut and grind the formation and break the rock.

[0031] Specifically, a plurality of mud channels 5 are formed between any two of the drill blades 4, and the direction of the mud channels 5 is radially diffused to the surroundings along the drill bit. One to two water hole positioning rods 6 are provided based on the width of the mud channels 5 to ensure rock carrying and cooling of the drill bit.

[0032] Specifically, the diamond-impregnated composite sheet 3 is a composite body made by sintering natural or artificial diamond particles, tungsten carbide or cast carbide, metal and non-metal powders together, and has high wear resistance and hardness.

[0033] In order to better understand the present invention, the operation logic of the drill bit with dual functions of cutting and grinding is explained: at the beginning of operation, the PDC composite piece 2 has a sharp edge. Under the combined effect of drilling pressure and torque, it is easy to eat into and cut the rock, and the rock breaking efficiency is high. The diamond-impregnated composite piece 3 mainly plays the role of limiting the depth of the PDC composite piece 2 eating into the rock, avoiding the problem of early failure of the cutting teeth due to excessive impact load on the PDC composite piece 2. At the same time, under the friction of the bottom rock of the well, the diamond-impregnated composite piece 3 is worn, and the diamond particles begin to be exposed. In the later stage of operation, after the PDC composite piece 2 is worn to a certain extent, it becomes more difficult to eat into the rock. The diamond-impregnated composite piece 3 begins to bear part of the drilling pressure. The exposed diamond particles are small and can easily eat into the rock under a smaller drilling pressure. The diamond-impregnated composite piece 3 grinds the rock under the drive of rotational torque. While breaking the rock, it also weakens the rock, reduces the rock strength, and releases the internal stress of the rock, so that the worn PDC composite piece 2 continues to eat into the rock, thereby achieving the purpose of improving the rock breaking efficiency and service life of the drill bit.

[0034] The present invention also provides an application of a drill bit having dual functions of cutting and grinding, specifically, an application of the drill bit in drilling in highly abrasive hard formations.

[0035] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A drill bit with dual functions of cutting and grinding, characterized in that: The drill bit comprises: a drill bit column (1), a plurality of PDC composite sheets (2), a plurality of diamond-impregnated composite sheets (3), and a plurality of drill bit blades (4); Wherein, a plurality of drill blades (4) are arranged on the drill bit column (1); a plurality of rows of rock breaking elements are arranged on each of the drill blades (4), and each row of the rock breaking elements is composed of a plurality of the PDC composite sheets (2) or a plurality of the impregnated diamond composite sheets (3); and the height of the PDC composite sheets (2) on the drill blade (4) is greater than the height of the impregnated diamond composite sheets (3) on the drill blade (4).

2. The drill bit having dual functions of cutting and grinding according to claim 1, characterized in that: The height of the PDC composite sheet (2) on the drill blade (4) is 0.5-2.0 mm higher than the height of the diamond-impregnated composite sheet (3) on the drill blade (4).

3. The drill bit with dual functions of cutting and grinding according to claim 1, characterized in that: Arranging a plurality of rows of rock-breaking elements on each of the drill blades (4) comprises: arranging two or three rows of rock-breaking elements on each of the drill blades (4); The first row of rock-breaking elements consists of a plurality of the PDC composite sheets (2), and the second row of rock-breaking elements consists of a plurality of the impregnated diamond composite sheets (3); or the first row of rock-breaking elements consists of a plurality of the PDC composite sheets (2), the second row of rock-breaking elements consists of a plurality of the impregnated diamond composite sheets (3), and the third row of rock-breaking elements consists of a plurality of the PDC composite sheets (2).

4. The drill bit having dual functions of cutting and grinding according to claim 3, characterized in that: Each of the diamond-impregnated composite sheets (3) in the second row is arranged in the same track behind each of the PDC composite sheets (2) in the first row, and each of the PDC composite sheets (2) in the third row is arranged in the same track or in a different track behind each of the diamond-impregnated composite sheets (3) in the second row.

5. The drill bit having dual functions of cutting and grinding according to claim 4, characterized in that: The back tilt angle of the PDC composite sheet (2) is 10-20°, and the back tilt angle of the diamond-impregnated composite sheet (3) is 0°.

6. The drill bit with dual functions of cutting and grinding according to claim 1, characterized in that: The number of the drill blades (4) is 6-8.

7. The drill bit with dual functions of cutting and grinding according to claim 1, characterized in that: The plurality of drill blades (4) include a plurality of short wings and long wings that are spaced apart.

8. The drill bit with dual functions of cutting and grinding according to claim 1, characterized in that: The impregnated diamond composite sheet (3) is obtained by sintering natural or artificial diamond particles, tungsten carbide or cast carbide, metal and non-metal powders together.

9. The drill bit with dual functions of cutting and grinding according to claim 1, characterized in that: The drill bit further comprises: a plurality of mud channels (5) formed between any two of the drill bit blades (4).

10. Application of the drill bit according to any one of claims 1 to 9, characterized in that: The drill bit is used in drilling in highly abrasive hard formations.

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