A downhole plugging diverter for reverse circulation drilling

Abstract

The present invention discloses a reverse circulation drilling downhole plugging diverter. The plugging diverter comprises a main shaft and a sealing ring; the outer edge of the main shaft is processed with two raised circular steps, namely the first step and the second step; the first step is located above the lateral channel, and the second step (29) is located above the first step; the outer edge of the first step is processed with an axial groove parallel to the main shaft axis; the outer edge of the second step is processed with a circumferential groove perpendicular to the main shaft axis; the sealing ring is installed in the circumferential groove of the second step. The sealing ring can prevent the lower drilling medium from returning to its upper part, and the sealing ring can be bent downward when the drilling tool is lifted, and large well wall blocks can fall to the lower part of the plugging diverter through the sealing ring and the axial groove, thereby reducing the risk of drill stuck at the plugging diverter.

Description

Technical Field

[0001] The invention relates to the field of drilling tools, in particular to a reverse circulation drilling downhole plugging diverter. Background Art

[0002] The method of circulating medium from the bottom of the well to the surface from the center of the drill pipe is called reverse circulation center sampling drilling. Single-layer, double-layer or triple-layer drill pipes are usually used, but double-wall drill pipes are the most common. The circulating medium is pressed into the annulus between the two pipes and carries the cuttings (core) from the center of the inner pipe, so this method is called double-tube reverse circulation or double-wall drill pipe reverse circulation drilling. With the continuous innovation of reverse circulation drilling theory and drilling technology, reverse circulation drilling technology is increasingly used in mineral exploration, water well drilling and oil drilling. Positive and negative alternating gas reverse circulation drilling technology is a form of reverse circulation drilling. Compared with oil drilling rigs, its newly added equipment mainly includes gas box, double-wall drill pipe and downhole plugging diverter; the drilling tool structure is generally faucet + gas box + double-wall drill tool + downhole plugging diverter + conventional drill tool + drill bit; during drilling, compressed air enters the annular gap of the double-wall drill pipe through the gas box, and reaches the conventional drill tool along the annular gap. The gas returned from the conventional drill tool carries the cuttings through the large annulus between the drill tool and the wellbore to the downhole plugger, and returns to the ground from the inner tube of the double-wall drill tool. During the use of conventional downhole plugging diverters, the lower cuttings may enter the upper annulus, and the large upper pieces cannot fall to the lower part of the downhole plugging diverter, which may easily cause the risk of stuck drill. Summary of the invention

[0003] The purpose of the present invention is to provide a reverse circulation drilling downhole plugging diverter to address the problems existing in the prior art, so as to reduce the risk of drill sticking at the plugging diverter.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following design scheme: A reverse circulation drilling downhole plugging diverter includes a main shaft and a sealing ring. The upper and lower parts of the main shaft are respectively connected to a double-wall drill tool and a conventional drill tool. The double-wall drill tool includes an inner tube and an outer tube, a drilling medium return channel is formed inside the inner tube, and a drilling medium injection channel is formed between the inner tube and the outer tube. The sealing ring is a rubber sealing ring, which is processed into a circular rubber sheet; the main shaft is an axial short section, with a main channel A and a main channel B axially processed inside, and a lateral channel processed radially; the main channel A is a through hole, and the drilling medium passing through the double-wall drill tool injection channel enters the internal channel of the lower conventional drill tool through the main channel A; the main channel B is a blind hole axially processed from top to bottom inside the main shaft, which is connected to the double-wall drill tool return channel and the lateral channel respectively; the outer edge of the main shaft is processed with two raised circular steps, which are the first step and the second step respectively; the first step is located above the lateral channel, and the second step is located above the lateral channel. The step is located above the first step, and the outer diameter of the second step is smaller than that of the first step; the outer edge of the first step is processed with an axial groove parallel to the main shaft axis; the outer edge of the second step is processed with a circumferential groove perpendicular to the main shaft axis; the sealing ring is installed in the circumferential groove of the second step, and the outer diameter of the sealing ring is larger than that of the second step; a large annulus is formed between the double-wall drilling tool and the conventional drilling tool and the wellbore, and the sealing ring of the second step divides the large annulus into an upper large annulus and a lower large annulus, and the drilling medium returned from the lower large annulus enters the double-wall drilling tool return channel through the lateral channel and the main channel B in turn.

[0005] The upper end surface of the second step is preferably a slope surface, and a bump is processed on the upper end of the slope surface. The axial groove processed on the outer edge of the first step is preferably a left-handed spiral groove. The lateral channel 25 is at an angle of 60 degrees with the axis of the main shaft 21.

[0006] The advantages of the present invention are that the sealing ring can prevent the lower drilling medium from returning to its upper part, and the sealing ring can be bent downward when the drill bit is lifted up, and large well wall blocks can fall to the lower part of the plugging diverter through the sealing ring and the axial groove, thereby reducing the risk of drill sticking at the plugging diverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 The invention is a reverse circulation drilling downhole plugging diverter Figure 2 Schematic diagram of the section along AA.

[0008] Figure 2 The present invention is a top view schematic diagram of a reverse circulation drilling downhole plugging diverter.

[0009] Figure 3 The invention is a reverse circulation drilling downhole plugging diverter Figure 2 Schematic diagram of the cross section along BB.

[0010] In the figure: 10. double-wall drilling tool, 11. inner tube, 12. outer tube, 13. return channel, 14. injection channel, 20. downhole plugging diverter, 21. main shaft, 22. bump, 23. circumferential groove, 24. axial groove, 25. lateral channel, 26. main channel A, 27. main channel B, 28. first step, 29. second step, 210. sealing ring. DETAILED DESCRIPTION

[0011] The following is combined with Figure 1 , Attachment Figure 2 and attached Figure 3 The present invention is further described:

[0012] Embodiment 1, a reverse circulation drilling downhole plugging diverter, comprising a main shaft 21 and a sealing ring 210; wherein:

[0013] The main shaft 21 is a shaft-shaped short section, and the upper and lower ends are respectively provided with joints for connecting with the double-wall drilling tool 10 and the conventional drilling tool. The main channel A26 and the main channel B27 are processed in the axial direction, and the lateral channel 25 is processed in the radial direction. 26 is a through hole that penetrates from top to bottom, and is connected with the double-wall drill injection channel 14 and the internal channel of the conventional drill; the main channel B27 is a blind hole processed axially from top to bottom inside the main shaft 21, and is connected with the double-wall drill return channel 13 and the lateral channel 25 respectively; the outer edge of the main shaft 21 is processed with two raised circular steps, namely the first step 28 and the second step 29; the first step 28 is located above the lateral channel 25, and the second step 29 is located above the first step 28, and the outer diameter of the second step 29 is smaller than the outer diameter of the first step 28; the outer edge of the first step 28 is processed with an axial groove 24; the outer edge of the second step 29 is processed with a circumferential groove 23; the sealing ring 210 is installed in the circumferential groove 23 of the second step, and the outer diameter of the sealing ring 210 is larger than the outer diameter of the second step 29.

[0014] Embodiment 2, based on embodiment 1, further, the sealing ring 210 is a circular rubber ring.

[0015] The upper end surface of the second step 29 is a slope surface, and a protrusion 22 is processed on the upper end of the slope surface.

[0016] The axial groove 24 processed on the outer edge of the first step is a left-handed spiral groove.

[0017] The lateral channel 25 forms an angle of 60 degrees with the axis of the main shaft 21 .

[0018] Typical embodiment 3, a reverse circulation drilling downhole plugging diverter includes a main shaft 21 and a sealing ring 210. The upper and lower parts of the main shaft 21 are respectively connected to a double-walled drilling tool 10 and a conventional drilling tool (not shown in the figure), and the double-walled drilling tool 10 includes an inner tube 11 and an outer tube 12, and a drilling medium return channel 13 is formed inside the inner tube 12, and a drilling medium injection channel 14 is formed between the inner tube and the outer tube. The sealing ring 210 is a circular rubber sheet; the main shaft 21 is a shaft-shaped short section, and the main channel A26 and the main channel B27 are axially processed inside, and the lateral channel 25 is radially processed; the main channel A26 is a through hole, and the drilling medium passing through the double-walled drilling tool injection channel 14 enters the internal channel of the lower conventional drilling tool through the main channel A26. The main channel B27 is a blind hole axially processed from top to bottom inside the main shaft 21, which is connected to the double-walled drilling tool return channel 13 and the lateral channel 25 respectively.

[0019] The outer edge of the main shaft 21 is processed with two raised circular steps, namely the first step 28 and the second step 29; the first step 28 is located above the lateral channel 25, and the second step 29 is located above the first step 28, and the outer diameter of the second step 29 is smaller than the outer diameter of the first step 28. The outer edge of the first step 28 is processed with an axial groove 24 parallel to the axial direction of the main shaft 21; the outer edge of the second step 29 is processed with a circumferential groove 23 perpendicular to the axial direction of the main shaft 21; the sealing ring 210 is installed in the circumferential groove 23 of the second step, and the outer diameter of the sealing ring 210 is larger than the outer diameter of the second step 29. A large annulus is formed between the double-wall drilling tool and the conventional drilling tool and the wellbore. The sealing ring 210 of the second step 29 divides the large annulus into an upper large annulus and a lower large annulus. The drilling medium returned from the lower large annulus enters the double-wall drilling tool return channel 13 through the lateral channel 25 and the main channel B27 in turn. The upper end surface of the second step 29 is a slope surface, and a bump 22 is processed on the upper end of the slope surface. The axial groove 24 processed on the outer edge of the first step is a left-handed spiral groove; the lateral channel 25 forms an angle of 60 degrees with the axis of the main shaft 21.

[0020] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A reverse circulation drilling downhole plugging diverter, characterized in that It comprises a main shaft (21) and a sealing ring (210); wherein: The main shaft (21) is a shaft-shaped short section, and the upper and lower ends are respectively provided with joints for connecting with the double-wall drilling tool (10) and the conventional drilling tool. The main channel A (26) and the main channel B (27) are processed in the axial direction, and the lateral channel (25) is processed in the radial direction. (26) is a through hole that penetrates from top to bottom, and is connected to the double-walled drilling tool injection channel (14) and the internal channel of the conventional drilling tool; the main channel B (27) is a blind hole that is axially processed from top to bottom inside the main shaft (21), and is connected to the double-walled drilling tool return channel (13) and the lateral channel (25) respectively; the outer edge of the main shaft (21) is processed with two raised circular steps, namely the first step (28) and the second step (29); the first step (28) is located above the lateral channel (25), and the second step (29) is located above the first step (28), and the outer diameter of the second step (29) is smaller than the outer diameter of the first step (28); the outer edge of the first step (28) is processed with an axial groove (24); the outer edge of the second step (29) is processed with a circumferential groove (23); the sealing ring (210) is installed in the circumferential groove (23) of the second step, and the outer diameter of the sealing ring (210) is larger than the outer diameter of the second step (29); The upper end surface of the second step (29) is a sloped surface, and a protrusion (22) is processed on the upper end of the sloped surface; the axial groove (24) processed on the outer edge of the first step is a left-handed spiral groove.

2. A reverse circulation drilling downhole plugging diverter according to claim 1, characterized in that: The sealing ring (210) is a circular rubber ring.

3. A reverse circulation drilling downhole plugging diverter according to claim 1, characterized in that: The lateral channel (25) forms an angle of 60 degrees with the axis of the main shaft (21).

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