Flushing mechanism for bit balling drum

Abstract

The flushing mechanism comprises a flushing head and a drill bit arranged at the lower end of the flushing head, and the flushing head is provided with a central cavity channel; a flushing channel is formed in the wall of the center cavity channel, an outlet of the flushing channel corresponds to a drill bit chip groove, and an inlet of the flushing channel is located in the inner wall of the center cavity channel. The fixing piece is fixed in the central cavity channel; the central cavity channel is cut off by the fixing piece, and a first through main hole is formed in the fixing piece; an inserting groove is formed between the fixing piece and the inner wall of the central cavity channel, a first side hole is formed in the position, at the inserting groove, of the fixing piece, and the first side hole is opposite to the inlet position of the flushing channel; the movable part can be arranged in the central cavity channel in a telescopic mode in the axial direction through an elastic assembly, and the central cavity channel is cut off through the movable part; the movable piece is provided with an inserting part, a second side hole is formed in the inserting part, and the inserting part extends into the inserting groove; and the movable piece is provided with a plug part, and a second through main hole is further formed in the movable piece. The device has the beneficial effects that the drilling displacement is changed through ground operation, so that the pressure drop of the drill bit is changed, the spring force is overcome, and a flushing channel is opened and closed, so that drilling fluid from the cleaning bypass directly flushes a drill bit chip removal groove, drill bit balling is treated, and the drill bit balling is prevented; the device is simple in structure, good in cleaning effect, long in service life and high in reliability.

Description

Technical Field

[0001] The invention relates to the technical field of drilling tools, in particular to a flushing mechanism for drilling bit mud packing. Background Art

[0002] During the drilling process of oil and gas or natural gas extraction, the drill bit will be wrapped in mud (referred to as mud packing) when drilling or pulling out. When the drill bit is covered with mud, the drill teeth of the drill bit cannot leak out, resulting in the drill teeth being unable to make contact with the well wall, so the drill bit cannot move forward and can only be pulled out, which seriously affects the extraction speed of oil and gas.

[0003] There are many reasons for the formation of mud balling, which can be roughly divided into geological factors, mud performance factors, engineering technology and operation factors, drill bit selection factors, etc. When mud balling occurs, the drill bit is affected by the mud balling and the degree of "digging" into the formation is reduced, resulting in its drilling force not being able to function normally, the drilling speed being slowed down, and in severe cases, the drill cannot be moved, there is no footage, and the drill can only be forced to pull out, increasing costs and labor intensity. The "piston pulling" phenomenon occurs when pulling out and drilling; the mud cannot be filled in when pulling out, resulting in suction, causing the pressure of the downhole liquid column to decrease, and the oil, gas and water in the formation enter the wellbore, causing the downhole to collapse, seriously causing the consequences of blowout and fire; at the same time, the mud is polluted; when drilling, it is easy to cause downhole pressure fluctuations, and the instability of the well wall causes the blockage and the pressure leakage of the formation to cause well leakage. After the occurrence of mud balling on the drill bit, it may also cause annular blockage and cause a stuck drill accident. In addition, when the piston and valve rubber of the mud pump, the rubber of the water hose and screw and the debris in the mud block the water hole of the drill bit, it may also cause mud packing on the drill bit and may also cause pressure buildup and damage to the mud pump drilling tools.

[0004] At present, both at home and abroad, when dealing with drill bit mud packing, the drill bit is repeatedly idling and circulating at large displacement at different depths and directions in the wellbore to remove the mud packing. However, this method is very ineffective, and it is unknown when and whether the mud packing will be removed, so the entire process of dealing with the mud packing is very long.

[0005] Based on his own experience, the inventor has previously designed an auxiliary device for flushing mud bags on drill bits. When the auxiliary device was used in actual drilling, customers gave feedback that the mud bag removal effect was good, but the reliability might not be ideal. For example, in terms of service life, the flushing head needed to be replaced after every period of drilling.

[0006] Therefore, based on the customer's requirements - "simple structure, high reliability, and excellent mud removal effect", the inventor adopted a new design idea. Summary of the invention

[0007] The object of the present invention is to overcome the shortcomings of the prior art, provide a flushing mechanism for bit balling, solve the problems of difficult balling cleaning and low reliability during cleaning, and achieve improved reliability on the basis of a simplified structure, and can achieve an excellent bit balling removal effect by a pressure less than that during drilling.

[0008] The object of the present invention is achieved by the following technical solutions: A flushing mechanism for bit balling, including a flushing head, which is arranged between the drill pipe and the bit of the oil and gas well, and has a central cavity that communicates the drill pipe and the bit;

[0009] A flushing channel is opened on the wall of the central cavity, the outlet of the flushing channel corresponds to the chip removal groove of the bit, and the inlet of the flushing channel is located at the inner wall of the central cavity;

[0010] It further includes:

[0011] A fixing member, which is fixed in the central cavity;

[0012] The fixing member truncates the central cavity, and a through first main hole is opened on the fixing member;

[0013] A slot is formed between the fixing member and the inner wall of the central cavity, and a first side hole is opened on the fixing member at the slot, and the first side hole is opposite to the inlet position of the flushing channel;

[0014] A movable member, which is axially telescopically arranged in the central cavity through an elastic component, and truncates the central cavity;

[0015] The movable member has an insertion portion, and a second side hole is opened on the insertion portion, and the insertion portion extends into the slot; when the movable member moves axially, the first side hole, the second side hole, and the inlet of the flushing channel can be connected, and when the movable member moves axially, the insertion portion can truncate the first side hole and the inlet of the flushing channel;

[0016] The movable member has a plugging head, and a through second main hole is also opened on the movable member; when the movable member moves axially, the plugging head can block the first main hole, and when the movable member moves axially, the plugging head and the first main hole can be in an unblocked state, and at this time the central cavity is penetrated through the first main hole and the second main hole.

[0017] As a preferred technical solution of the present application, in the central cavity, a movable member is arranged below the fixing member; drilling fluid is introduced into the upper inlet of the central cavity. When the drilling fluid reaches the set pressure value, the plug is pushed away from the first main hole, and the drilling fluid flows through the first main hole and the second main hole into the inner hole of the bit. When the drilling fluid decreases to the set pressure value, the plug abuts against the first main hole for blocking. At this time, the first side hole, the second side hole, and the inlet of the flushing channel are aligned with each other, and the drilling fluid flushes the chip removal groove of the bit through the outlet of the flushing channel.

[0018] Further, the fixing member is a downwardly concave barrel shape; the outer cylindrical surface of the upper part of the fixing member has an annular protrusion, and the annular protrusion is fitted with the inner wall of the central cavity through threads; the lower part of the fixing member and the central cavity form an annular slot. A first main hole is opened at the bottom of the concave position of the fixing member, and a first side hole is opened at the side wall of the concave position of the fixing member.

[0019] Further, the movable member is also in a downwardly concave barrel shape; the upper part of the movable member is an annular insertion part; a plug protruding upward is provided at the center of the bottom of the concave part of the movable member, and a plurality of second main holes are also opened at the bottom of the concave part of the movable member, and a plurality of second side holes are opened at the side wall of the concave part of the movable member; when the liquid flows through the plurality of second main holes and the plurality of second side holes respectively, the flow rate of the liquid flowing through the plurality of second main holes is greater than the flow rate flowing through the plurality of second side holes.

[0020] As a preferred technical solution of the present application, the elastic component includes a spring and a force-receiving member, the force-receiving member is fixed on the inner wall of the central cavity, and both ends of the spring abut against the force-receiving member and the movable member respectively.

[0021] As a preferred technical solution of the present application, the first main hole is in a conical hole shape with a smaller upper part and a larger lower part, and the plug head is correspondingly in a conical head shape or a spherical shape.

[0022] As a preferred technical solution of the present application, the drill bit is installed at the lower end surface of the flushing head, and the drill bit is communicated with the central cavity; when the drill bit is installed at the lower end of the flushing head, the outlets of some flushing channels are not aligned with the chip discharge groove of the drill bit, and the outlets of the flushing channels not aligned with the chip discharge groove are blocked by threaded posts, and nozzles are threadedly installed at the outlets of the flushing channels aligned with the chip discharge groove.

[0023] As a preferred technical solution of the present application, the first side holes and the second side holes are inclined from top to bottom and from inside to outside, and the upper section of the flushing channel has a corresponding inclined section; the diameters of the first side holes, the second side holes, and the flushing channel decrease in sequence.

[0024] Further, the movable part has an extending part, the extending part is in contact with the force-receiving member and a lower sealing ring is arranged between the two; an annular column-shaped closed cavity is formed between the extending part, the force-receiving member and the central cavity, and the spring is located in this closed cavity.

[0025] For the convenience of understanding, the working principle of this solution is described:

[0026] During normal drilling, a relatively large pressure of the bit pressure drop (e.g., 4 MPa) is introduced into the upper part of the central cavity. At this time, the drilling fluid acts on the plug head, causing the plug head to open the blocked first main hole. Then, the drilling fluid in the upper part of the central cavity flows through the first main hole, the second main control, and finally into the inner hole of the bit, and the flushing channel is closed, so normal drilling is carried out. (It should be noted that the cross-sectional area of the first main hole should be larger than the sum of the areas of all the second main holes. When the drilling fluid acts on the movable part, a downward force will be generated. When this downward force is greater than the elastic force of the spring, the plug head and the first main hole will always be in an open state);

[0027] When a mud ball appears on the bit, the displacement of the drilling fluid introduced is reduced to decrease the bit pressure drop (e.g., reduced to 2 MPa). Then, the downward pressure generated by the drilling fluid on the movable part is less than the elastic force of the spring, so the movable part moves upward, and finally the plug head abuts against the first main hole to seal the first main hole. At this time, when the movable part moves upward, the first side hole is connected to the inlet of the flushing channel through the second side hole. Then, the drilling fluid in the upper part of the central cavity flows through the first side hole, the second side hole, and the flushing channel, and the drilling fluid jets and cleans the mud ball in the chip groove of the bit through the nozzle - the mud ball is removed;

[0028] It should be noted that in this solution, it is found that when flushing the mud ball at the chip groove of the bit, the drilling fluid does not require too much pressure to achieve good cleaning (not requiring too much pressure means reducing the drilling fluid for the normal operation of the original bit - for example, reducing from 4 MPa to 2 MPa can also achieve cleaning).

[0029] The present invention has the following advantages:

[0030] (1) Simple structure, high service life, and high reliability;

[0031] (2) It is found that the mud ball can be removed by reducing the pressure of the drilling fluid, and the cleaning effect is very good. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of the plug head blocking the first main hole in the present invention;

[0033] Figure 2 is Figure 1 a partial structural schematic diagram in;

[0034] Figure 3 is a schematic structural diagram of the plug head separated from the first main hole in the present invention;

[0035] Figure 4 is Figure 3 a partial structural schematic diagram in;

[0036] In the figure: 10 - flushing head, 11 - central cavity, 12 - flushing channel, 13 - nozzle;

[0037] 20 - fixing member, 21 - first main hole, 22 - first side hole, 23 - annular protrusion;

[0038] 30 - slot;

[0039] 40 - movable member, 41 - insertion part, 42 - second side hole, 43 - plugging head, 44 - second main hole, 45 - protruding part;

[0040] 50 - elastic component, 51 - spring, 52 - force - receiving member. Detailed implementation manners

[0041] The present invention will be further described below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0042] It should be noted that the orientation or positional relationship indicated by "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0043] It should be noted that, without conflict, the embodiments in the present invention and the features and technical solutions in the embodiments can be combined with each other.

[0044] As Figures 1 to 4 shown, a flushing mechanism for a bit balling includes a flushing head 10 and a drill bit. The drill bit is installed at the lower end of the flushing head. An axial central cavity 11 is formed in the flushing head 10, and the central cavity 11 communicates with the inner hole of the drill bit; the drilling fluid introduced from the central cavity 11 can be discharged from the inner hole of the drill bit;

[0045] Wherein, a flushing channel 12 is formed on the wall of the central cavity 11. The outlet of the flushing channel 12 corresponds to the chip - discharging groove of the drill bit, and the inlet of the flushing channel 12 is located at the inner wall of the central cavity 11;

[0046] It further includes a fixing member 20 and a movable member 40. The fixing member 20 is fixedly installed in the central cavity 11, and the movable member 40 is arranged in the central cavity 11 through an elastic component 50 so as to be able to axially expand and contract; both the fixing member 20 and the movable member 40 cut off the central cavity 11;

[0047] Among them, a first main hole 21 penetrating axially is formed in the fixing member 20, and a first side hole 22 is formed in the fixing member 20. The inlet and outlet of the first side hole are located at the upper surface and the outer side surface of the fixing member 20 respectively.

[0048] Moreover, a slot 30 is formed between the outer side surface of the fixing member 20 and the inner wall of the central cavity 11. An insertion portion 41 is provided at the upper part of the movable member 40, and the insertion portion 41 is inserted into the slot 30. A second side hole 42 is formed in the insertion portion 41. When the movable member 41 moves axially, the insertion portion 41 moves up and down in the slot 30, and when it moves to a certain position, the second side hole 42 can be opposite to the position of the first side hole 22 and the inlet of the flushing channel 11, that is, the first side hole 22, the second side hole 42, and the inlet of the flushing channel 11 are communicated with each other.

[0049] In addition, a plug portion 43 is further provided on the movable member 40. The plug portion 43 is opposite to the position of the first main hole 21. When the movable member 40 moves axially, the plug portion 43 can abut against the first main hole 21 to block it, or the plug portion 43 is separated from the first main hole 21 to open the first main hole 21. In addition, a plurality of second main holes 44 penetrating axially are formed in the movable member 40.

[0050] Moreover, a movable member 40 is arranged below the fixing member 20 in the central cavity 11.

[0051] When the drill bit is performing normal drilling work, drilling fluid with a set value (this set pressure value is required for normal drilling, for example, 4 MPa) is introduced at the upper inlet of the central cavity 11. The drilling fluid pushes the plug 43 away from the first main hole 21. The drilling fluid acts on the movable member 40 (making the cross-sectional area of the first main hole 21 larger than the sum of the cross-sectional areas of all the second main holes 44) to generate a downward pressure. This downward pressure overcomes the elastic force of the elastic component 50. Then, the drilling fluid flows downward through the first main hole 21 and the second main holes 44 into the inner control of the drill bit.

[0052] When there is mud cake on the drill bit and it needs to be cleaned, the drilling fluid pressure value at the upper part of the central cavity 11 is adjusted to be smaller (it can be adjusted on the ground, and adjusting the drilling fluid pressure is an existing technology. Here, for example, it can be adjusted to 2 MPa). Then, the downward pressure generated by the drilling fluid on the movable part 40 is not enough to overcome the elastic force of the elastic component 50. So, the movable part 40 moves upward, and then the plug head 43 blocks the first main hole 21. At this time, the second side hole 42 on the movable part 40 aligns with the first side hole 22 and the flushing channel 12 - the three are connected. Then, the drilling fluid in the upper part of the central cavity 11 flows into the flushing channel 12, and the drilling fluid at the outlet of the flushing channel 12 cleans the chip removal groove of the drill bit, and can clean the mud cake at the chip removal groove. After cleaning for a period of time, then rotate the drill bit, and part of the mud cake on the drill teeth of the drill bit can be removed. After cleaning like this for a period of time and then rotating the drill bit, even under the action of a relatively small amount of drilling fluid, the mud cake on the drill bit can still be cleaned well, and the cleaning effect is good.

[0053] Next, the structure of the cementing part 20 will be further described.

[0054] As Figures 1 to 4 shown, the fixing part 20 is in the shape of a downward - concave barrel, and there is an annular protrusion 23 on the outer cylindrical surface of the upper part of the fixing part 20. During installation, the annular protrusion 23 is fitted with the inner wall of the central cavity 11 through threads, and the lower part of the fixing part 20 and the central cavity 11 form an annular slot 30.

[0055] In addition, a first main hole is opened at the bottom of the concave position of the fixing part 20, and a first side hole 22 is opened at the side wall of the concave position of the fixing part 20.

[0056] Next, the structure of the movable part 40 will be further described.

[0057] Referring to Figures 1 to 4 , the movable part 40 is also in the shape of a downward - concave barrel. The upper part of the movable part 40 is an annular insertion part 45, and a second side hole 42 is opened on the side wall of the insertion part.

[0058] In addition, there is an upward - protruding plug head 43 at the center of the bottom of the concave part of the movable part 40. And, there are also a plurality of second main holes 44 opened at the bottom of the concave part of the movable part 40.

[0059] During operation, when the liquid flows through the plurality of second main holes 44 and the plurality of second side holes 42 respectively, the flow rate of the liquid flowing through the plurality of second main holes 44 is greater than the flow rate of the liquid flowing through the plurality of second side holes 42.

[0060] Next, the elastic component 50 will be further described.

[0061] The elastic component 50 includes a spring 51 and a force-receiving member 52. The force-receiving member 52 is fixed to the inner wall of the central cavity 11, and the two ends of the spring 51 respectively abut against the force-receiving member 52 and the movable member 40.

[0062] Furthermore, the movable part 40 has an extending part 45. The extending part 45 is in contact with the force-receiving member 52, and a lower sealing ring is arranged between them. An annular cylindrical closed cavity is formed among the extending part 45, the force-receiving member 52 and the central cavity, and the spring 51 is located in this closed cavity.

[0063] Optionally, in this embodiment, the first main hole 21 is in the shape of a tapered hole that is smaller at the top and larger at the bottom, and the plug head 43 is correspondingly in the shape of a tapered head or a spherical shape.

[0064] Optionally, in this embodiment, the drill bit is installed at the lower end face of the flushing head, and the drill bit communicates with the central cavity 11. When the drill bit is installed at the lower end of the flushing head, the outlets of some of the flushing channels 12 are not aligned with the chip removal grooves of the drill bit. The outlets of the flushing channels 12 that are not aligned with the chip removal grooves are blocked by threaded posts, and nozzles 13 are threadedly installed at the outlets of the flushing channels 12 that are aligned with the chip removal grooves.

[0065] Optionally, in this embodiment, the first side hole 22 and the second side hole 42 are inclined from top to bottom and from inside to outside, and the upper section of the flushing channel 12 has a corresponding inclined section. The diameters of the first side hole 22, the second side hole 42, and the flushing channel 12 decrease in sequence.

[0066] The above embodiments only represent relatively preferred implementation manners, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. Flushing mechanism for drill bit mud packing, characterized by: include: A flushing head (10) is arranged between a drill pipe and a drill bit of an oil and gas well, and has a central cavity (11) for connecting the drill pipe and the drill bit; A flushing channel (12) is opened on the wall of the central cavity (11), the outlet of the flushing channel (12) corresponds to the chip removal groove of the drill bit, and the inlet of the flushing channel (12) is located at the inner wall of the central cavity (11); A fixing member (20) fixed in the central cavity (11); The fixing member (20) cuts off the central cavity (11), and a first main hole (21) is formed on the fixing member (20) to penetrate through the fixing member (20); a slot (30) is formed between the fixing member (20) and the inner wall of the central cavity (11), and a first side hole (22) is formed on the fixing member (20) at the slot (30), and the first side hole (22) is opposite to the inlet position of the flushing channel (12); A movable member (40) is axially telescopically arranged in the central cavity (11) via an elastic component (50), and cuts off the central cavity (11); The movable member (40) has an insertion portion (41) on which a second side hole (42) is formed, and the insertion portion (41) extends into the slot (30); when the movable member (40) moves in the axial direction, the first side hole (22), the second side hole (42), and the inlet of the flushing channel (12) are connected; when the movable member (40) moves in the axial direction, the insertion portion (41) can cut off the inlet of the first side hole (22) and the flushing channel (12); The movable member (40) has a plugging portion (43), and the movable member (40) is also provided with a penetrating second main hole (44); when the movable member (40) moves in the axial direction, the plugging portion (43) can block the first main hole (21); when the movable member (40) moves in the axial direction, the plugging portion (43) and the first main hole (21) are in an unblocked state, and at this time, the central cavity (11) penetrates through the first main hole (21) and the second main hole (44).

2. The flushing mechanism for drill bit mud balls according to claim 1, characterized in that: A movable part (40) is arranged below the fixed part (20) in the central cavity (11); The upper inlet of the central cavity (11) is filled with drilling fluid; When the drilling fluid reaches a set pressure value, the plug (43) is pushed away from the first main hole (21), allowing the drilling fluid to flow through the first main hole (21) and the second main hole (44) to the inner hole of the drill bit; When the drilling fluid is reduced to a set pressure value, the plug (43) abuts against the first main hole (21) to seal it. At this time, the first side hole (22), the second side hole (42) and the inlet of the flushing channel (12) are aligned with each other, and the drilling fluid flushes the chip removal groove of the drill bit through the outlet of the flushing channel (12).

3. The flushing mechanism for drill bit mud balls according to claim 2, characterized in that: The fixing member (20) is in the shape of a barrel which is concave downwards; The upper outer cylindrical surface of the fixing member (20) has an annular protrusion (23), and the annular protrusion (23) is engaged with the inner wall of the central cavity (11) through a thread; the lower part of the fixing member (20) and the central cavity (11) form an annular slot (30); A first main hole is opened at the bottom of the recessed position of the fixing piece (20), and a first side hole (22) is opened at the side wall of the recessed position of the fixing piece (20).

4. The flushing mechanism for drill bit mud balls according to claim 3, characterized in that: The movable member (40) is also in the shape of a barrel that is concave downwards; The upper portion of the movable member (40) is an annular insertion portion (41); The bottom center of the recess of the movable part (40) is provided with a plug (43) protruding upward, the bottom of the recess of the movable part (40) is also provided with a plurality of second main holes (44), and the side wall of the recess of the movable part (40) is provided with a plurality of second side holes (42); when liquid flows through the plurality of second main holes (44) and the plurality of second side holes (42) respectively, the flow rate of liquid flowing through the plurality of second main holes (44) is greater than the flow rate of liquid flowing through the plurality of second side holes (42).

5. The flushing mechanism for drill bit mud balls according to any one of claims 1 to 4, characterized in that: The elastic component (50) comprises a spring (51) and a force-bearing member (52). The force-bearing member (52) is fixed to the inner wall of the central cavity (11). Two ends of the spring (51) respectively abut against the force-bearing member (52) and the movable member (40).

6. The flushing mechanism for drill bit mud balls according to claim 5, characterized in that: The movable part (40) has a protruding part (45), the protruding part (45) is in contact with the force-bearing member (52), and a lower sealing ring is arranged between the two. A cylindrical closed cavity is formed between the protruding portion (45), the force-bearing member (52) and the central cavity, and the spring (51) is located in the closed cavity.

7. The flushing mechanism for drill bit mud balls according to claim 1, characterized in that: The first main hole (21) is a tapered hole that is smaller at the top and larger at the bottom, and the plugging portion (43) is correspondingly tapered or spherical.

8. The flushing mechanism for drill bit mud balls according to claim 1, characterized in that: The drill bit is installed at the lower end surface of the flushing head, and the drill bit is connected to the central cavity (11); When the drill bit is installed at the lower end of the flushing head, the outlets of some flushing channels (12) are not aligned with the chip groove of the drill bit. The outlets of the flushing channels (12) that are not aligned with the chip groove are blocked by threaded columns, and the outlets of the flushing channels (12) that are aligned with the chip groove are threadedly installed with nozzles (13).

9. The flushing mechanism for drill bit mud balls according to claim 1, characterized in that: The first side hole (22) and the second side hole (42) are arranged obliquely from top to bottom and from inside to outside, and the upper section of the flushing channel (12) has a corresponding oblique section; The diameters of the first side hole (22), the second side hole (42), and the flushing channel (12) decrease in sequence.

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