Drill Bit Mud Bag Flushing Aid

Abstract

The present invention relates to a mud bag flushing aid for a drill bit while drilling, comprising an upper joint and a lower joint, wherein the lower joint is telescopically sleeved on the lower part of the upper joint, wherein the upper end of the upper joint is connected to the drill string by a thread, and the lower end of the lower joint is connected to the drill bit by a thread; the upper joint is provided with a central pipe along the axis, the central pipe is communicated with the central hole of the drill tool and the inner hole of the drill bit respectively, and a diversion hole is provided on the side wall of the central pipe; a replaceable gland is installed at the lower end of the lower joint, and the gland can be provided with the same number of nozzles as the number of the chip grooves of the drill bit, when the diversion hole of the upper joint is communicated with the drainage hole of the lower joint, the drill bit is cleaned from the outside, and when drilling is normal, the drainage hole and the diversion hole are closed, and the drilling fluid completely passes through the drill bit. The beneficial effects achieved by the present invention are: when the drill bit is not subjected to drilling pressure, the chip groove of the drill bit is flushed from top to bottom, the flushing effect is good, the mud bag is easily removed, the pure mechanical structure design has high reliability, and the filter screen plug is installed to prevent the water eye of the drill bit from being blocked.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole drilling equipment, in particular to downhole tools for drilling oil, natural gas, coalbed methane and geological exploration and development, and is particularly suitable for solving the problems of drill bit mud packing and drill bit water hole blockage in oil and gas exploration geological drilling. Background Art

[0002] In the process of oil and gas or natural gas extraction, mud packing and water hole blockage will occur in the process of drilling and tripping, which is unavoidable. Taking the actual situation as an example, in 2019, a well in the southwest oil and gas field in Sichuan, which was drilled by a drilling company in Xinjiang, used 5-6 blade drill bits at 500-1000m, with a drilling pressure of 8-14 tons and a density of 1.2-1.45g / cm 3 , potassium chloride polymer drilling fluid with a funnel viscosity of 50S, was used for drilling sandstone intercalated with mudstone; during the wellbore drilling process, drill bit mud packing occurred as many as 5 times; specifically, the drilling speed was basically 3 to 10 minutes per meter, and suddenly it slowed down to 30 to 60 minutes per meter, and later it became even slower until it could not be drilled and was forced to pull out. The drill bit was severely packed with mud, which seriously affected the speed of oil and gas exploration and development.

[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.

[0004] 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.

[0005] 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.

[0006] Some companies install water holes at the chip flutes of the drill bit to flush the mud bags at the chip flutes, but these methods are theoretical and lack practical experience, and are ineffective in actual use. This is because when a water hole at a chip flute is blocked by mud bags, the drilling fluid used for flushing can flow out from other chip flutes that are not blocked by mud bags, so the water hole at the blocked chip flute will not flush with much force.

[0007] To this end, the applicant has designed a drill bit mud bag flushing aid based on his own practical work experience and technical accumulation over the years, striving to be practical and to solve the above-mentioned problems. Summary of the invention

[0008] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a drilling bit mud bag flushing aid which can flush the chip groove of the drill bit from top to bottom, easily remove mud bags, have good flushing effects, prevent drill bit mud bags, have a purely mechanical structure design, and have high reliability.

[0009] The object of the present invention is achieved by the following technical scheme: a drilling bit mud bag flushing auxiliary device comprises an upper joint and a lower joint, the lower joint is telescopically sleeved on the lower part of the upper joint, the upper end of the upper joint is connected to the drill string, and the lower end of the lower joint is connected to the drill bit; the upper joint is provided with a central pipe along the axis, the central pipe is respectively connected to the central hole of the drill string and the flushing hole of the drill bit, and the side wall of the central pipe is provided with a diversion hole;

[0010] The lower joint is provided with drainage holes on its circumference which are opposite to the chip grooves of the drill bit. When the drill bit is not pressurized (i.e. when the drill bit leaves the bottom of the well), the upper joint and the lower joint are in an extended state, and the diversion holes are connected with the drainage holes to realize flushing of the chip grooves of the drill bit. When the upper joint and the lower joint are in a compressed state during pressurized drilling, the diversion holes are closed, and all the drilling fluid flows out from the water holes of the drill bit without affecting drilling.

[0011] Furthermore, the lower joint is sleeved on the upper joint with a spline structure, and a spring A is arranged between the two to achieve upward and downward expansion and contraction.

[0012] Preferably, the outer side surface of the upper joint has an upper shoulder and a lower shoulder, and a filter plug is also provided at the inlet of the central pipe of the upper joint; when the lower joint retracts, it abuts against the lower shoulder, and a spring A is provided between the lower shoulder and the upper end surface of the lower joint.

[0013] Furthermore, the lower joint is in the shape of a tube shell, and its inner hole is divided into three parts: an upper part, a middle part and a lower part, and the inner diameters of the three parts increase successively, the connection between the upper part and the middle part is a stepped hole, and the connection between the middle part and the lower part is a tapered hole;

[0014] The inner hole has a spline structure at the upper part and slides up and down with the upper joint to transmit torque for installation, and the lower part is installed in cooperation with the drill bit through an internal thread.

[0015] Furthermore, a telescopic slide rod is provided on the side wall of the lower part of the central pipe, and the telescopic slide rod is pressed against the stepped platform with the conical surface of the inner hole through a spring B. When the drill tool is lifted, the central tube of the upper joint drives the telescopic slide rod to move inward, reducing the flow rate of the central pipe to the water eye of the drill bit.

[0016] Furthermore, a telescopic slide rod is also provided at the side wall of the lower part of the central pipe, and a tenon-shaped slide groove is opened at the tapered hole of the inner hole. The outer end of the telescopic slide rod is tenon-shaped and is installed in cooperation with the slide groove. The telescopic slide rod is telescoped by means of a sleeve spring B. When the upper joint moves upward, the telescopic slide rod moves inward to reduce the flow rate of the central pipe to the drill bit water eye.

[0017] A nozzle is also provided at the outlet of the drainage hole of the lower joint, and the nozzle is opposite to the chip removal groove of the drill bit.

[0018] Furthermore, a pressure cap is screwed onto the outside of the lower end of the lower joint, and a plurality of water holes corresponding to the drill bit chip grooves are opened on the lower wall of the pressure cap; the pressure cap is a commonly used replacement part, and 4-8 holes for installing nozzles can be provided, which can be selected on site according to the number of drill bit chip grooves, and the outlet of the drainage hole is a large-diameter installation hole, and the nozzle is installed therein and extends from the water hole.

[0019] Preferably, a pressure plate is provided on the upper sleeve of the nozzle, and a spring C is provided on the outer cylindrical sleeve of the nozzle. The spring C is respectively pressed between the pressure cover and the pressure plate. When there is flushing liquid in the drainage hole, the pressure plate presses the nozzle downward so that the nozzle is closer to the chip removal groove of the drill bit.

[0020] Preferably, the inlet of the drainage hole is wide-mouthed.

[0021] The present invention has the following advantages:

[0022] (1) The flushing structure facing the chip groove of the drill bit can effectively flush and deal with the drill bit mud bag in time to restore normal drilling even if mud bag is formed during drilling; when connecting a single root, it can effectively prevent the drill bit from mud bagging, and it has good practicality and flushing effect;

[0023] (2) The telescopic design of the upper and lower joints is ingenious. No flushing is required when drilling. Each time the drill is lifted, the diversion hole is automatically connected to the drainage hole to achieve flushing of the chip groove of the drill bit. This can not only flush the mud bag but also avoid the formation of mud bag. All of this is achieved through a purely mechanical mechanism. For deep wellbores, it is more reliable.

[0024] (3) The upper joint and the lower joint are directly arranged between the drilling tool and the drill bit, and are respectively connected to the center hole of the drill string and the center hole of the drill bit. This solution is applicable to various drilling tools currently on the market, and there is no need to improve the drilling tools, and it has high versatility;

[0025] (4) The setting of the conical step on the telescopic slide rod and the lower joint can reduce the flow into the drill bit and increase the flushing pressure at the nozzle to avoid mud packing of the drill bit when flushing the chip groove when lifting the drill.

[0026] (5) The nozzle structure is designed to be retractable so that it is closer to the chip groove of the drill bit during flushing, thereby increasing the flushing force and further ensuring the flushing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the upper and lower joints in a compressed state;

[0028] Figure 2 It is a structural schematic diagram of the lower part of the lower joint;

[0029] Figure 3 It is a schematic diagram of the installation structure at the nozzle;

[0030] Figure 4 is a structural schematic diagram of the upper joint;

[0031] Figure 5 is a schematic diagram of the structure of the lower joint;

[0032] In the figure: 1-upper joint, 101-center pipe, 102-diverter hole, 2-lower joint, 201-drainage hole, 3-spring A, 4-buffer limit block, 5-telescopic slide rod, 6-spring B, 7-reverse buckle locking nut, 8-nozzle, 9-pressure cover, 10-pressure plate, 11-spring C, 12-filter plug. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following description.

[0034] like Figures 1 to 5 As shown in the figure, the drill bit mud bag flushing auxiliary device is arranged between the drill tool and the drill bit, and flushes the chip groove of the drill bit above the drill bit. The flushing auxiliary device can be retracted, and the water outlet is closer to the drill bit chip groove during flushing; and the telescopic slide bar 5 arranged between the upper joint 1 and the lower joint 2 of the flushing auxiliary device can be retracted to reduce the water channel of the upper joint center pipe. During flushing, the flow rate through the drill bit water eye can be reduced, and the flow rate flowing into the diversion hole 102 of the lower joint 2 can be increased, thereby increasing the flushing force on the drill bit chip groove from top to bottom.

[0035] This solution uses a telescopic upper joint 1 and a lower joint 2. The lower joint 2 is telescopically sleeved on the lower part of the upper joint 1. The upper end of the upper joint 1 is connected to the drill tool through a thread, and the lower end of the lower joint 2 is connected to the drill bit through a thread. The lower joint 2 is provided with a plurality of drainage holes 201 in the circumference. The outlet of the drainage hole 201 is aligned with the chip groove of the drill bit. When there is mud in the chip groove, it can be flushed. Figure 1 shown.

[0036] Since the drill tool itself has a center hole and the drill bit also has a center hole, the water hole of the drill bit is connected to the center hole of the drill bit. Therefore, in this solution, the upper joint 1 has a center pipe 101 along the axis, and the center pipe 101 is connected to the center hole of the drill string; the cavity formed by the lower joint 2 and the upper joint 1 is connected to the center hole of the lower joint 2. That is, the liquid flows from the center hole of the drill string into the center pipe 101, then into the cavity of the upper joint 1 and the lower joint 2, then into the center hole of the drill bit, and finally flows out from the water hole of the drill bit, as shown in FIG. Figure 1 shown.

[0037] In order to flush the drainage holes 201, the side wall of the central pipe 101 is provided with diversion holes 102, and each diversion hole 102 corresponds to a drainage hole 201. Figure 2 When the upper joint 1 and the lower joint 2 are in the extended state, the diverter hole 102 is connected with the drainage hole 201 to achieve flushing of the drill chip groove; when the upper joint 1 and the lower joint 2 are in the compressed state, the diverter hole 102 is closed by the inner wall of the lower joint 2. In order to facilitate water inlet, the inlet of the drainage hole 201 is wide-mouthed, and sealing members (not shown in the figure) can be provided on the side walls of the upper joint 1 and the lower joint 2 at the upper and lower positions of the inlet of the drainage hole 201.

[0038] In this solution, the lower joint 2 is in the shape of a tube shell, and its inner hole is divided into three parts: upper, middle and lower parts, and the inner diameters of the three parts increase successively. The connection between the upper and middle parts is a stepped hole, and the connection between the middle and lower parts is a tapered hole.

[0039] Specifically, the inner hole has a spline structure at the upper part and slides up and down with the upper joint 1, and these spline structures are also used to transmit torque, and the lower part is installed in cooperation with the drill bit through an internal thread.

[0040] A telescopic slide rod 5 is also provided on the side wall of the lower part of the central pipe 101, and a tenon-shaped slide groove is opened at the tapered hole of the inner hole. The outer end of the telescopic slide rod 5 is tenon-shaped and is installed in cooperation with the slide groove. The telescopic slide rod 5 is telescoped by means of a sleeve spring B6. When the upper joint 1 moves upward, the telescopic slide rod 5 moves inward to reduce the flow rate of the central pipe 101 to the drill bit water eye.

[0041] In this scheme, if Figure 1 and Figure 2 As shown, the lower part of the upper joint 1 is in the shape of a central tube, and the lower part is covered with a buffer limit block 4 to prevent the lower joint 2 from falling. The buffer limit block 4 is screwed on the reverse lock nut 7 at the lower part of the upper joint and locked. A spring D is also provided between the buffer limit block 4 and the lower joint 2 (as shown in FIG. Figure 1 and Figure 2 shown).

[0042] A retractable nozzle 8 is also provided at the outlet of the drainage hole 201. When the nozzle 8 is extended, it is closer to the chip removal groove of the drill bit.

[0043] Preferably, a gland 9 is screwed onto the outside of the lower end of the lower joint 2, and a plurality of water holes are opened on the lower wall of the gland 9 (the glands 9 with different numbers of water holes can be replaced at any time according to the number of drill chip grooves, 4 holes to 9 holes, and fixed to the lower joint 2), the outlet of the drainage hole 201 is a large-diameter mounting hole, and the nozzle 8 is installed in the large-diameter mounting hole of the drainage hole 201 and extends out of the water hole; a pressure plate 10 is provided on the upper outer sleeve of the nozzle 8, and a spring C11 is provided on the outer cylindrical sleeve of the nozzle 8, and the spring C11 is respectively pressed between the gland 9 and the pressure plate 10. When there is flushing liquid in the drainage hole 201, the nozzle 8 is pressed downward so that the nozzle 8 is closer to the drill chip groove.

[0044] In this embodiment, the outer side of the upper joint 1 has an upper shoulder and a lower shoulder, and a filter plug 12 is also provided at the inlet of the central pipe 101 of the upper joint 1; when the lower joint 2 is retracted, it abuts against the lower shoulder, and the spring A3 is provided between the lower shoulder and the upper end surface of the lower joint 2. The surface of the lower shoulder of the upper joint 1 and the upper end surface of the lower joint 2 are both provided with slots for accommodating the spring A3, and the spring A3 can be as shown in FIG. Figure 1 As shown, a spring sleeve is arranged, and multiple springs A3 with small diameters can also be arranged circumferentially along the axis of the auxiliary device.

[0045] At the same time, the bottom surface of the lower shoulder of the upper joint 1 and the upper end surface of the lower joint 2 are in contact with each other using concave and convex step surfaces to ensure position accuracy.

[0046] The above embodiments only express several preferred modes of the present invention, but they cannot be understood as limiting the scope of the present invention. For those skilled in the art, several modifications and improvements made without departing from the concept of the present utility model are all within the protection scope of the present utility model.

Claims

1. Drill bit mud bag flushing aid, characterized by: The flushing auxiliary device is telescopic and comprises an upper joint (1) and a lower joint (2), wherein the lower joint (2) is telescopically sleeved on the lower part of the upper joint (1), wherein the upper end of the upper joint (1) is connected to the drill string, and the lower end of the lower joint (2) is connected to the drill bit; the upper joint (1) is provided with a central pipe along the axis, wherein the central pipe is respectively connected to the central hole of the drill string and the flushing hole of the drill bit, and a diversion hole (102) is provided on the side wall of the central pipe (101); the lower joint (2) is provided with a drainage hole (201) in the circumferential direction thereof which is opposite to the position of the drill bit chip groove; when the upper joint (1) and the lower joint (2) are in an extended state, the diversion hole (102) is connected to the drainage hole (201) so as to realize flushing of the drill bit chip groove; when the upper joint (1) and the lower joint (2) are in a compressed state during pressurized drilling of the drill bit, the diversion hole (102) is closed, and the drilling fluid flows out of the drill bit water hole completely without affecting the drilling; A telescopic slide rod (5) is also provided at the side wall of the lower part of the central pipe (101), and a tenon-shaped slide groove is opened at the tapered hole of the inner hole. The outer end of the telescopic slide rod (5) is tenon-shaped and is installed in cooperation with the slide groove. The telescopic slide rod (5) is telescoped by a sleeve spring B (6). When the upper joint (1) moves upward, the telescopic slide rod (5) moves inward to reduce the flow of the central pipe (101) to the drill bit water hole; The lower joint (2) is in the shape of a tube shell, and its inner hole is divided into three parts: an upper part, a middle part and a lower part, and the inner diameters of the three parts increase successively. The connection between the upper part and the middle part is a stepped hole, and the connection between the middle part and the lower part is a tapered hole. The upper part of the inner hole is a spline structure and can slide up and down with the upper joint (1) and can transmit torque. The lower part is installed with a drill bit through an internal thread. A pressure cap (9) is screwed onto the outside of the lower end of the lower joint (2), and a plurality of water holes corresponding to the drill bit chip groove are opened on the lower wall of the pressure cap (9); the outlet of the drainage hole (201) is a large-diameter mounting hole, and the nozzle (8) is mounted therein and extends out of the water hole; a pressure plate (10) is provided on the upper outer sleeve of the nozzle (8), and a spring C (11) is provided on the outer cylindrical sleeve of the nozzle, and the spring C (11) is respectively pressed between the pressure cap (9) and the pressure plate (10), and when there is flushing liquid in the drainage hole (201), the pressure plate (10) presses the nozzle downward so that the nozzle is closer to the drill bit chip groove.

2. The drilling bit mud bag flushing auxiliary device according to claim 1 is characterized in that: The lower joint (2) is sleeved on the upper joint (1) with a spline structure, and a spring A (3) is provided between the two to achieve upward and downward expansion and contraction.

3. The drilling bit mud bag flushing auxiliary device according to claim 2 is characterized in that: The outer side surface of the upper joint (1) has an upper shoulder and a lower shoulder, and a filter plug (12) is also provided at the inlet of the central pipe (101) of the upper joint (1); When the lower joint (2) is retracted, it abuts against the lower shoulder, and the spring A (3) is arranged between the lower shoulder and the upper end surface of the lower joint (2).

4. The drilling bit mud bag flushing aid according to claim 3, characterized in that: The lower part of the upper joint (1) is in the shape of a central tube, and is covered with a buffer stopper (4) for preventing the lower joint (2) from falling. The buffer stopper (4) is screwed onto a reverse locking nut (7) at the lower part of the upper joint and locked. A spring D is also provided between the buffer stopper (4) and the lower joint (2).

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