A wellbore coring drill adapted for use in high permeability formations in open hole wells

Abstract

The present application belongs to the technical field of drilling coring device in the technology of oil geological exploration and well drilling, and discloses a borehole wall coring drilling tool suitable for high permeability formation of open hole, which comprises a drill bit, a plurality of chip removal holes are arranged on the side wall of the drill bit at intervals; a drill rod, one end of the drill rod is connected with the drill bit, and a plurality of spiral hollowed-out mud guide grooves are arranged on the rod wall of the drill rod at intervals and close to the drill bit. The spiral hollowed-out mud guide grooves are arranged on the rod wall of the drill rod at intervals and close to the drill bit, so that the scraping function is added to the inner and outer walls of the drill rod, the mud cake on the borehole wall can be shredded, the closed space is destroyed, the mud cake is thrown out of the drill bit by using the rotation characteristics of the drill bit, the mud slurry washes the rock debris and the drill bit, and finally the rock debris is discharged from the chip removal hole, the drilling of the rock core is reduced in resistance, the probability of drill pipe sticking is reduced, and the success rate of coring is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of drilling-type coring devices in petroleum geological exploration well technology, specifically relating to a wellbore coring tool adapted to high-permeability formations in open-hole wells. Background Technology

[0002] Currently, the core drilling tools used in open-hole wells are greatly affected by formation characteristics and mud systems, and have high requirements for well conditions. Before each core drilling operation, the well must be dredged and the mud cake around the wellbore must be scraped off. The mud specific gravity should be 1.5 g / cm³. 3 As the application of rotary coring continues to expand, the market is extending from exploratory wells to development wells. Wellbore conditions and mud properties are becoming more complex, especially in high-permeability (thick mud cake) formations, where coring yields are significantly reduced.

[0003] To save costs, traditional wellbore coring tools have several mud-removal holes on the drill pipe. When coring in high-permeability formations, the drill bit gets encased in a thick layer of mud cake. Rock cuttings generated after drilling into the formation are sealed by the mud cake, preventing mud and fluids from entering the drilled rock. As the drill bit penetrates deeper, it becomes stuck due to the increasing and expanding rock cuttings. Releasing the stuck bit requires increasing the cable tension, which can cause the drill bit to break and damage the precision mechanical structures connecting it. This renders the equipment unusable and can even lead to logging and retrieval accidents, posing significant engineering risks to coring operations and greatly reducing the success rate. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a wellbore coring tool adapted to high-permeability formations in open-hole wells. Its purpose is to reduce drilling resistance, decrease the probability of stuck drill bit, and improve the success rate of coring.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0006] A wellbore coring tool adapted to high-permeability formations in open-hole wells, comprising:

[0007] A drill bit, wherein a plurality of chip removal holes are spaced apart on the sidewall of the drill bit;

[0008] A drill rod, one end of which is connected to the drill bit, and a plurality of spiral hollow mud guide grooves are spaced apart on the rod wall near the drill bit.

[0009] Furthermore, the drill bit is provided with chip removal grooves corresponding to the positions of each chip removal hole.

[0010] Furthermore, the width of the chip removal groove is 9mm to 11mm.

[0011] Furthermore, several of the chip removal holes are evenly distributed along the circumference of the drill bit.

[0012] Furthermore, the spiral hollow mud guide grooves described herein have the same rotation direction.

[0013] Furthermore, a drill rod positioning keyway is provided on the rod wall of the drill rod at a position away from the drill bit.

[0014] Furthermore, the wall thickness of the drill rod at the location where the spiral hollow mud guide groove is opened is 6mm to 9mm.

[0015] Furthermore, the diameter of the chip removal hole is 4mm to 6mm.

[0016] Furthermore, the drill bit and the drill rod are integrally formed.

[0017] Furthermore, the outer surface of the drill bit is a cemented surface inlaid with diamonds.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] This invention provides a wellbore coring tool adapted to high-permeability formations in open-hole wells. Several spirally perforated mud guide grooves are spaced apart on the drill pipe wall near the drill bit. This adds a scraping function to the inner and outer walls of the drill pipe, breaking up the mud cake on the wellbore and disrupting its enclosed space. Utilizing the rotational characteristics of the drill bit, the mud cake is thrown out of the drill bit, allowing the mud to wash away rock cuttings and the drill bit, ultimately achieving the purpose of discharging rock cuttings from the cuttings removal hole. In other words, the spiral shape of the mud guide grooves facilitates mud cake discharge, and under high-speed rotation, it has a cutting effect on the mud cake, opening the channel between the well fluid and the drill bit, which is beneficial for cooling the drill bit and removing cuttings. It also breaks up the thick mud cake covering the drill bit, establishing a smooth system between the drill bit, formation, and mud, reducing drilling resistance, lowering the probability of stuck drill bit, and improving the core recovery success rate.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the wellbore coring tool according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the drill bit end face structure of the wellbore coring tool according to an embodiment of the present invention.

[0024] In the diagram: 1-Drill bit; 100-Chip removal hole; 101-Chip removal groove; 2-Drill rod; 200-Spiral hollow mud guide groove; 201-Drill rod positioning keyway. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Combination Figure 1 and Figure 2 As shown in the figure, an embodiment of the present invention provides a wellbore coring tool adapted to high permeability formations in open-hole wells, including a drill bit 1 and a drill rod 2. The side wall of the drill bit 1 is provided with a plurality of chip removal holes 100 spaced apart. One end of the drill rod 2 is connected to the drill bit 1, and the rod wall of the drill rod 2 is provided with a plurality of spiral hollow mud guide grooves 200 spaced apart near the drill bit 1.

[0027] Specifically, several spiral-shaped perforated mud guide grooves 200 are spaced apart on the wall of drill pipe 2 near drill bit 1. This adds a scraping function to the inner and outer walls of drill pipe 2, which can crush the mud cake on the well wall, destroy its closed space, and use the rotational characteristics of drill bit 1 to throw the mud cake out of drill bit 1, allowing the mud to wash away rock cuttings and drill bit, ultimately achieving the purpose of discharging rock cuttings from the cuttings discharge hole 100. In other words, the spiral shape of the mud guide grooves facilitates mud cake discharge, and under high-speed rotation, it has a cutting effect on the mud cake, opens the channel between well fluid and drill bit, facilitates the cooling of drill bit and cuttings removal, opens the thick mud cake covering the drill bit, and establishes a smooth system between drill bit, formation and mud, reducing the resistance of core drilling, reducing the probability of stuck drill bit, and obtaining high-permeability formation cores of interest to geologists.

[0028] Based on the above embodiments, as a more preferred embodiment, combined with Figure 1 and Figure 2 As shown, a chip removal groove 101 is also provided on the drill bit 1 at the position corresponding to each chip removal hole 100. That is to say, a chip removal hole 100 is provided in each chip removal groove 101, which is conducive to the rock cuttings discharged from the chip removal hole 100 being discharged through the corresponding chip removal groove 101, thereby better preventing the rock cuttings from clogging.

[0029] Combination Figure 1 and Figure 2As shown, preferably, a plurality of chip removal holes 100 are evenly distributed along the circumference of the drill bit 1, so that rock cuttings from all directions can be uniformly discharged during drilling. For example, three chip removal holes 100 are evenly distributed along the circumference of the drill bit 1, and each chip removal hole 100 is provided with a chip removal groove 101 at a corresponding position.

[0030] In some embodiments, such as Figure 1 As shown, the spiral hollow mud guide grooves 200 have the same rotation direction, ensuring that the spiral hollow mud guide grooves 200 can be opened evenly, thereby making the cutting and discharge of mud cake more effective.

[0031] In some embodiments, such as Figure 1 As shown, a drill rod positioning keyway 201 is provided on the rod wall of the drill rod 2 at a position away from the drill bit 1. The drill rod 2 can be quickly installed and removed through the drill rod positioning keyway 201.

[0032] Preferably, the wall thickness of the drill rod 2 at the location of the spiral hollow mud guide groove 200 is 6mm to 9mm, the diameter of the chip removal hole 100 is 4mm to 6mm, and the diameter of the chip removal groove 101 is 9mm to 11mm. The drill bit 1 and the drill rod 2 are integrally formed. With the increase in the area of ​​the chip removal and mud guide grooves, in order to ensure the strength of the drill bit and the realization of the above design, a large-particle drill bit with a large outer diameter is adopted, while the inner diameter uses the size of a conventional drill bit. The spiral design is achieved by increasing the wall thickness of the drill rod, changing the original separate design of the drill bit and drill rod to an integral form, thus increasing the strength of the drilling tool.

[0033] In some embodiments, the outer surface of drill bit 1 is a cemented surface inlaid with diamonds. The integrated drill bit is machined in a CNC machine tool, and then diamonds are inlaid and sintered on the end face of the drill bit. The strength of the cementation is consistent with the conventional drill bit manufacturing process, which will not be described in detail here.

[0034] The wellbore coring tool of this embodiment has the following advantages: First, it increases the end area of ​​the coring drill bit and the area of ​​the chip removal groove, which is 1.5 times larger than the original. Second, it changes the mud removal hole on the drill rod into a spiral hollow mud guide groove, increasing the mud guide area by 3 times. The hollow design is adopted, and the outer wall of the drill rod forms a spiral shape that facilitates mud scraping. Third, it makes the drill bit and drill rod into a whole, which not only increases the hollow area of ​​the drill bit but also strengthens the strength of the drill bit.

[0035] Because the rocks in high-permeability layers are relatively soft, this embodiment increases the width of the drill bit's cuttings removal groove, the area of ​​the drill pipe's mud removal, and the wall thickness of the drill pipe by 1.5 times. Hardness testing of the wellbore coring tool in this embodiment showed no deformation even with a torque of 7 N·m, indicating that the tool met the usage requirements. Actual well testing was conducted in the Putaohua Formation of Daqing Oilfield, a typical high-permeability formation. During drilling, to ensure downhole pressure balance, the mud cake in this formation is very thick. Using conventional wellbore coring tools, the core recovery rate was almost zero. Using the wellbore coring tool of this embodiment, the core recovery success rate reached 60%, solving the oilfield company's need for lithological analysis of these high-yield layers. This invention, while maintaining the necessary hardness and strength of the wellbore coring tool, modifies the drill pipe and drill bit structure, enhancing mud removal and cuttings removal capabilities.

[0036] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this invention, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0041] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wellbore coring tool adapted to high-permeability formations in open-hole wells, characterized in that, include: A drill bit (1) has a plurality of chip removal holes (100) spaced apart on its sidewall; a chip removal groove (101) is also provided on the drill bit (1) corresponding to the position of each chip removal hole (100). Drill rod (2), one end of which is connected to the drill bit (1), and a plurality of spiral hollow mud guide grooves (200) are spaced apart on the rod wall of the drill rod (2) near the drill bit (1), and the spiral hollow mud guide grooves (200) have the same direction of rotation.

2. The wellbore coring tool for high-permeability formations in open-hole wells according to claim 1, characterized in that, The width of the chip removal groove (101) is 9mm~11mm.

3. The wellbore coring tool adapted to high-permeability formations in open-hole wells according to claim 1, characterized in that, Several of the chip removal holes (100) are evenly distributed along the circumference of the drill bit (1).

4. The wellbore coring tool for high-permeability formations in open-hole wells according to claim 1, characterized in that, A drill rod positioning keyway (201) is provided on the rod wall of the drill rod (2) at a position away from the drill bit (1).

5. A wellbore coring tool adapted to high-permeability formations in open-hole wells according to claim 1, characterized in that, The wall thickness of the drill rod (2) at the location where the spiral hollow mud guide groove (200) is opened is 6mm~9mm.

6. The wellbore coring tool adapted to high-permeability formations in open-hole wells according to claim 1, characterized in that, The diameter of the chip removal hole (100) is 4mm to 6mm.

7. A wellbore coring tool adapted to high-permeability formations in open-hole wells according to claim 1, characterized in that, The drill bit (1) and the drill rod (2) are integrally formed.

8. A wellbore coring tool adapted to high-permeability formations in open-hole wells according to claim 1, characterized in that, The outer surface of the drill bit (1) is a cemented surface inlaid with diamonds.

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