An air reverse circulation double-helix plugger

Abstract

The present invention provides an air reverse circulation double-spiral plugger, comprising a lower plugging joint, an inner tube female joint, and a lower spiral plugging joint, wherein the lower spiral plugging joint is connected to a double-wall drill pipe by a designed male buckle, the inner tube of the double-wall drill pipe is inserted into the inner tube female joint, the lower plugging joint and the inner tube female joint are fixed by a lower plugging inner tube fixing screw, one end of the inner tube female joint is further provided with an upper plugging joint, the double-wall drill pipe is further connected to an upper spiral plugging joint by a designed female buckle, an inner tube male joint is further inserted into the inner tube of the double-wall drill pipe, and the inner tube male joint and the upper plugging joint are fixed by an upper plugging inner tube fixing screw. The device can concentrate rock cuttings in the middle of the double-spiral plugging during drilling, thereby sealing the hole wall gap, and the double-spiral plugging can be connected to a conventional double-wall drill pipe in one or more groups and placed in the hole to achieve a better sealing effect.

Description

Technical Field

[0001] The invention relates to the technical field of geological drilling, in particular to an air reverse circulation double-helix plugger. Background Art

[0002] Reverse circulation drilling technology is a type of air drilling technology. Compressed air enters the annular gap between the inner and outer tubes of the double-wall drill pipe through the air tap, and reaches the bottom hole drill bit along the annular gap, breaking the rock to form rock cuttings through the drill bit. When the compressed air is blown out of the bottom hole drill bit, the pressure offset will produce a reverse circulation, thereby carrying the rock cuttings into the inner tube of the double-wall drill pipe and blowing them out of the hole. The air reverse circulation continuous sampling and coring drilling technology can achieve continuous sampling. The sampling efficiency is higher than the drilling and coring efficiency, and the labor intensity is low. It is suitable for drilling in leaking formations and water-scarce areas, and therefore has been widely used worldwide.

[0003] While the air reverse circulation drilling process has high drilling efficiency, it also has obvious defects. That is, when drilling into the Quaternary system, air leakage is likely to occur, which will expand the borehole. Some air is blown out from the gap between the double-wall drill pipe and the hole wall, resulting in insufficient air returning from the center hole of the double-wall drill pipe to carry the drill cuttings to the surface, which is not conducive to the formation of reverse circulation, reduces drilling efficiency, and may even cause accidents such as drill sticking and drill burial. These problems affect the application of reverse circulation and become a major weakness affecting drilling efficiency.

[0004] There are currently two types of downhole annular space plugging tools in China. One type consists of multiple layers of rubber sandwiched between multiple layers of annular iron plates, which are fixed to the drill bit. The annular iron plates mainly serve to fix the rubber rings. They are not very wide, and the diameter of the rubber rings is equal to or slightly larger than the aperture, thus providing a plugging effect. The other type directly fixes an annular metal plate close to the aperture to the drill bit, which directly provides a plugging effect. Since it is difficult to form a regular circular hole in the borehole wall formed by impact drilling in the formation, the plugging effect of using a metal plate as a packer is difficult to meet the construction requirements. However, multi-layer rubber has a certain degree of elasticity, and its diameter can be slightly larger than the aperture. Even if the aperture is irregular, it can still provide a plugging effect. Because the diameter of the plugging tool is larger than that of the upper and lower drill bits, a protrusion is formed in the well. When there is fallen material on the upper part of the plugging tool, it is easy for it to accumulate at the plugging tool, thus posing a risk of drill stuck. When a stuck drill occurs, rubber plugging tools offer flexibility, ease of handling, and enhanced drilling safety. However, rubber has low strength, poor wear resistance, and a short service life. Metal plate plugging tools offer strong wear resistance and a long service life, but are difficult to handle when a drill is stuck, reducing drilling safety. While both plugging tools have their advantages, they also have significant drawbacks, which hinder their application in air drilling. Summary of the Invention

[0005] In response to the above problems, the present invention provides an air reverse circulation double-helix sealer. The double-helix sealer of the present invention is installed between the drill bit and the double-walled drill rod, and rotates with the drill rod. When encountering a covering layer, the covering layer and the debris after the drill bit is crushed can be accumulated in the middle of the double-helix seal through the bidirectional spiral, thereby sealing the gap between the double-walled drill rod and the hole wall, which is conducive to the formation of reverse circulation.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] An air reverse circulation double-spiral plugger comprises a lower plugging joint, an inner tube female joint and a lower spiral plugging joint, the lower spiral plugging joint being connected to a double-wall drill pipe via a designed male buckle, the inner tube of the double-wall drill pipe being inserted into the interior of the inner tube female joint, the lower plugging joint and the inner tube female joint being fixed via a lower plugging inner tube fixing screw, an upper plugging joint being further provided at one end of the inner tube female joint, the double-wall drill pipe being further connected to an upper spiral plugging joint via a designed female buckle, an inner tube male joint being inserted into the inner tube of the double-wall drill pipe, the inner tube male joint and the upper plugging joint being fixed via an upper plugging inner tube fixing screw.

[0008] Preferably, the inner tube female joint and the inner tube male joint are connected by a plug-in connection.

[0009] Preferably, the lower spiral plugging adopts a right-handed blade, which rotates clockwise along with the double-wall drill pipe during drilling to transport the debris in the drill hole upward.

[0010] Preferably, the upper spiral plugging adopts a left-handed blade, which rotates clockwise along with the double-wall drill pipe during drilling to transfer the debris in the drill hole downward.

[0011] Preferably, a hard alloy sheet is welded on the blade.

[0012] The beneficial effects of the present invention are:

[0013] 1. The double-direction spiral structure is used to collect the cuttings in the middle of the double-direction spiral plugging during the drilling process, thus sealing the gap between the hole walls.

[0014] 2. The double spiral plug is welded with carbide sheets to improve the wear resistance of the spiral blades;

[0015] 3. Double spiral plugging can be connected to conventional double-wall drill pipe in one or more groups and placed into the hole to achieve better sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the external structure of the present invention;

[0017] Figure 2 It is a schematic cross-sectional view of the double-helix plugging of the present invention.

[0018] In the figure: 1. Lower plugging joint; 2. Female joint for inner tube; 3. Upper plugging joint; 4. Male joint for inner tube; 5. Lower plugging inner tube fixing screw; 6. Carbide sheet; 7. Upper plugging inner tube fixing screw. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0022] Reference Figure 1-Figure 2The cam is provided with a screw thread 5 for the screw thread of the cam, and the cam is fixed with the screw thread 5 at one end and the screw thread 5 at the other end of the cam is fixed with the cam.

[0023] Furthermore, a plug-in connection is adopted between the inner tube female joint 2 and the inner tube male joint 4. The above method forms an air reverse circulation air intake channel and a central return sample channel. The two spirals concentrate the debris and the middle of the double spiral seal plays a sealing role.

[0024] Furthermore, the lower spiral plug adopts right-handed blades, which rotate clockwise along with the double-wall drill pipe during drilling, and transfer the debris in the borehole upward. The upper spiral plug adopts left-handed blades, which rotate clockwise along with the double-wall drill pipe during drilling, and transfer the debris in the borehole downward. Carbide sheets 6 are welded on the blades. In order to maintain the outer diameter of the double spiral plug, carbide sheets 6 are welded on the spiral blades to improve the wear resistance of the spiral blades and play a role in maintaining the diameter.

[0025] A plugger is a tool used to seal the annular gap between the borehole wall and the double-wall drill pipe. It is installed on the drill pipe as needed, with one or more sections depending on the formation conditions. It is lowered into the hole along with the drill pipe. During normal drilling, its double-helical blades gather loose sediment, sealing the annulus. During the drilling process, the double-walled annular plugging tool, inserted while drilling, not only seals the upper formation water but also prevents cuttings from flowing up the annulus and causing pipe sticking accidents. During drilling, the double-walled body, consisting of the outer and inner tubes of the double-walled short section, acts as a double-wall drill tool short section. The annular space between the outer and inner tubes of the double-walled short section serves as an air flow channel. The double-helical plugger can seal the upper formation water and prevent cuttings from flowing up the annulus, thereby reducing the risk of drilling accidents and improving reverse circulation efficiency.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An air reverse circulation double-helix occluder, characterized in that: The invention comprises a lower plugging joint (1), an inner tube female joint (2) and a lower spiral plugging joint, wherein the lower spiral plugging joint is connected to a double-wall drill pipe via a designed male buckle, the inner tube of the double-wall drill pipe is inserted into the inner tube female joint (2), the lower plugging joint (1) and the inner tube female joint (2) are fixed via a lower plugging inner tube fixing screw (5), one end of the inner tube female joint (2) is further provided with an upper plugging joint (3), the double-wall drill pipe is further connected to the upper spiral plugging joint via a designed female buckle, the inner tube of the double-wall drill pipe is further provided with an inner tube male joint (4), the inner tube male joint (4) and the upper plugging joint (3) are fixed via an upper plugging inner tube fixing screw (7); The inner tube female joint (2) and the inner tube male joint (4) are connected by a plug-in type; The lower spiral plugging adopts right-handed blades, which rotate clockwise along with the double-wall drill pipe during drilling, and transport the debris in the drill hole upwards; The upper spiral plugging uses left-handed blades, which rotate clockwise along with the double-wall drill pipe during drilling, transporting the debris in the borehole downward.

2. The air reverse circulation double-helix plugging device according to claim 1, characterized in that: A hard alloy sheet (6) is welded on the blade.

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