Drilling fluid flow control device for improving reliability of MWD signal

Abstract

The invention provides a drilling fluid flow control device for improving the reliability of an MWD signal. The method is used for solving the problem of poor MWD signal transmission stability during annulus return loss in the drilling process. Comprising an outer shell assembly and a sliding flow control assembly which are arranged in a sliding and sleeving mode, and a reset spring is arranged between the sliding flow control assembly and the outer shell assembly; the outer shell assembly comprises an upper connector assembly, the sliding flow control assembly comprises a flow control upper sleeve, a plurality of first liquid inlet holes communicated with an inner hole of the flow control upper sleeve are formed in the outer wall of the flow control upper sleeve, and when the reset spring is in a free state, the first liquid inlet holes are all communicated with the liquid inlet end of the upper connector assembly. An air bag is arranged in the upper connector assembly, and when the air bag is inflated, the sliding flow control assembly slides along the inner wall of the outer shell assembly, so that part or all of the first liquid inlet holes are blocked from the liquid inlet end of the upper connector assembly. By increasing the flow resistance in the drill string, the pressure of the drilling fluid in the drill string is reduced, and the reliability of MWD signal transmission is improved.

Description

Technical Field

[0001] The invention relates to the field of oil and gas well engineering, and in particular to a drilling fluid flow control device for improving the reliability of MWD signals. Background Art

[0002] Measurement While Drilling (MWD) refers to the technology of measuring drilling parameters and formation information near the drill bit during drilling, and transmitting this information to the ground in the form of mud pulses without interrupting normal drilling operations.

[0003] Through MWD technology, drilling personnel can timely understand the actual situation of the well, so as to adjust the drilling strategy and ensure the smooth progress of drilling operations. At present, there are two main methods for information transmission of measurement while drilling: wired transmission and wireless transmission. MWD commonly uses wireless transmission for information transmission. There are usually three types of wireless transmission: drilling fluid pulse method, acoustic wave method and electromagnetic wave method. Each method has its scope of application and limitations. Compared with the above three wireless transmission methods, mud pulse wireless transmission method is the most widely used. It uses circulating drilling fluid as the transmission medium, and the signal of the detected quantity is converted into a pulse wave generated by the flow control device to transmit the signal. Its technology is relatively mature and the process is relatively simple. It is simple and easy to operate in actual working conditions, and its performance is relatively reliable. It is currently the most widely used downhole information transmission method. However, there are many factors affecting the measurement of MWD instruments. The noise caused by instrument connection, drilling fluid circulation system and drill bit, well depth, drilling fluid performance adjustment, etc. affect the transmission of instrument signals.

[0004] When a wellbore leaks, the drilling fluid in the annulus leaks into the formation cracks. When the drilling fluid loss rate downhole is greater than the mud pumping rate of the drilling pump, the drilling fluid in the annulus cannot be replenished in time, which will cause the drilling fluid level in the annulus in the wellbore to drop, which directly causes the static column pressure of the drilling fluid to drop. The drilling fluid cannot pass through the MWD stably and continuously, affecting the reception and transmission of the MWD signal. Therefore, equipment is needed to ensure the reliability of the MWD signal when the annulus is lost due to leaks or other reasons.

[0005] At present, there are related studies on stabilizing MWD signals and eliminating signal influencing factors at home and abroad. The main research work on mud pulse signal extraction and identification is as follows: a detailed analysis of mud pulse signals and existing noise interference sources in wireless measurement while drilling systems is conducted, and the method of using wavelet neural network threshold denoising processing technology to detect effective signals from multi-frequency strong noise backgrounds with unfixed frequencies is discussed. Existing studies have established transfer function models of various components in the mud channel (flexible or rigid drill pipes, air bags, sudden contraction and expansion pipes, throttle holes, etc.), and modularized them so that they can be assembled arbitrarily to simulate different drill string structures. The focus is on studying the influence of ground pipelines such as risers and air bags on signal quality. Existing studies have conducted in-depth and detailed studies on the transmission speed of pressure wave signals, and studied the influence of drilling fluid density, gas content, solid concentration, drilling fluid type and diameter-thickness ratio on signal transmission speed; Wang Xiang proposed the frequency domain transmission speed of pressure wave signals and analyzed its influencing factors. However, the above methods have the problems of complex models and large computational complexity. Summary of the invention

[0006] The purpose of the present invention is to provide a drilling fluid flow control device that improves the reliability of MWD signals. It is used to solve the technical problem that when the annular fluid level drops to a certain level due to excessive leakage speed and the annular drilling fluid cannot be replenished in time after the existing drill string has lost circulation during drilling, the liquid in the drill string is sucked, resulting in negative pressure in the circulating drilling fluid in the drill main, which leads to poor stability of MWD signal transmission.

[0007] A drilling fluid flow control device for improving the reliability of an MWD signal, comprising an outer shell assembly, a sliding flow control assembly being slidably arranged in the outer shell assembly, and a return spring being arranged between the sliding flow control assembly and the outer shell assembly;

[0008] The outer shell assembly includes an upper joint assembly, the sliding flow control assembly includes a flow control upper sleeve, a plurality of first liquid inlet holes connected to the inner hole of the flow control upper sleeve are formed on the outer wall of the flow control upper sleeve, and when the reset spring is in a free state, the plurality of first liquid inlet holes are all connected to the liquid inlet end of the upper joint assembly;

[0009] An airbag is arranged in the upper joint assembly. When the airbag is inflated, the sliding flow control component slides along the inner wall of the outer shell component to block part or all of the first liquid inlet holes from the liquid inlet end of the upper joint assembly.

[0010] Optionally, a first sliding hole along the axial direction is formed at the lower end of the upper joint assembly, and a second liquid inlet hole along the axial direction is formed at the upper end of the upper joint assembly;

[0011] The first sliding hole is connected to the second liquid inlet hole, the diameter of the second liquid inlet hole is larger than the diameter of the first sliding hole, the flow control upper sleeve is slidably arranged in the first sliding hole, and when the reset spring is in a free state, several of the first liquid inlet holes are connected to the second liquid inlet holes.

[0012] Optionally, the upper end of the flow control upper sleeve is connected to a limiting sleeve;

[0013] The outer diameter of the limiting sleeve is larger than the outer diameter of the flow control upper sleeve, and the inner diameter of the limiting sleeve is smaller than the inner diameter of the flow control upper sleeve.

[0014] Optionally, a plurality of annular arrays of the first liquid inlet holes are arranged on a plurality of annular planes in the axial direction of the flow control upper sleeve.

[0015] Optionally, the outer shell assembly further includes an intermediate joint sleeve and a lower joint assembly;

[0016] One end of the middle joint sleeve is connected to the outer wall of the middle part of the upper joint assembly, and the other end of the middle joint sleeve is connected to one end of the lower joint assembly. A second sliding hole along the axial direction is provided in the lower joint assembly.

[0017] Optionally, the lower end of the flow control upper sleeve is connected to a flow control lower sleeve, and the flow control lower sleeve is slidably disposed in the second sliding hole;

[0018] A limit flange is arranged at the upper end of the flow control lower sleeve, and the limit flange is located in the piston cavity between the upper joint assembly and the lower joint assembly. The outer wall of the limit flange slides along the inner wall of the middle joint sleeve, and the reset spring is arranged between the limit flange and the lower joint assembly.

[0019] Optionally, a placement groove is provided on the outer wall of the upper joint assembly, and the placement groove and the inner wall of the intermediate joint sleeve form a placement cavity for placing the airbag;

[0020] The upper joint assembly is provided with an air inlet passage connecting the outer wall of the upper joint assembly with the airbag in the placement chamber, a first flow passage connecting the placement chamber with the piston chamber, a second flow passage connecting the piston chamber with the outer wall of the upper joint assembly, and a third flow passage connecting the placement chamber with the second flow passage.

[0021] Optionally, a one-way pressure balancing valve is provided in the second flow channel, and a one-way inflation valve is provided in the air inlet channel.

[0022] Optionally, a third liquid inlet connected to the piston cavity is provided on the outer wall of the intermediate joint sleeve, and the third liquid inlet is located at the lower part of the piston cavity.

[0023] Optionally, O-rings are provided between the upper joint assembly and the flow control upper sleeve, and between the lower joint assembly and the flow control lower sleeve.

[0024] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0025] 1. The flow control device of the present application reduces the pressure of the drilling fluid in the drill string by increasing the flow resistance in the drill string, reduces the probability of negative pressure in the drill string, and improves the reliability of MWD signal transmission.

[0026] 2. The present application controls the up and down movement of the sliding flow control assembly by the volume expansion of the inflated airbag, and changes the cross-sectional area of ​​the flow channel by controlling the number of first liquid inlet holes connected to the second liquid inlet holes. When a well leak occurs, the flow control device works faster and consumes less energy. It has a simple structure and can adapt to high temperature and high pressure conditions underground without failure.

[0027] 3. The working principle of the flow control device of the present application is based on the Bernoulli principle and the continuity equation. When the fluid passes through the flow control device, the reduction in the cross-sectional area of ​​the pipe leads to an increase in the flow rate. At this time, the kinetic energy of the liquid increases, and the total energy remains unchanged. Therefore, the energy conversion that occurs when the liquid passes through the flow control device is manifested as a pressure drop.

[0028] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings of the present invention are as follows.

[0030] Figure 1 It is a cross-sectional view of the drilling fluid flow control device of the present invention.

[0031] Figure 2 It is a three-dimensional structural view of the drilling fluid flow control device of the present invention.

[0032] Figure 3 It is a cross-sectional view of the upper joint assembly of the present invention.

[0033] Figure 4 For the present invention Figure 3 Cross-sectional view at AA in the middle.

[0034] Figure 5 It is a three-dimensional structural view of the upper joint assembly of the present invention.

[0035] Figure 6It is a schematic structural diagram of the sliding flow control component of the present invention.

[0036] Figure 7 It is a cross-sectional view of the lower joint assembly of the present invention.

[0037] Figure 8 It is a structural schematic diagram of the flow control device of the present invention when the drilling operation is normal.

[0038] Fig. 9 It is a schematic structural diagram of the present invention in which part of the first liquid inlet hole is blocked when annular space loss occurs.

[0039] Fig.10 It is a schematic diagram of the structure in which all first liquid inlet holes are blocked when annular space loss occurs in the present invention.

[0040] Fig.11 The figure is a schematic diagram of the installation position of the drilling fluid flow control device of the present invention on the drill string.

[0041] In the figure: 1-reset spring; 2-upper joint assembly; 201-first sliding hole; 202-second liquid inlet hole; 203-placement groove; 204-inlet channel; 205-first flow channel; 206-second flow channel; 207-third flow channel; 3-flow control upper sleeve; 301-first liquid inlet hole; 4-air bag; 5-limit sleeve; 6-middle joint sleeve; 601-piston chamber; 602-third liquid inlet; 7-lower joint assembly; 701-second sliding hole; 8-flow control lower sleeve; 801-limit flange; 9-one-way pressure balance valve; 10-one-way inflation valve; 11-O-ring. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] Example:

[0044] like Figure 1 and Figure 2 A drilling fluid flow control device for improving the reliability of MWD signals is shown, characterized in that it comprises an outer shell assembly, a sliding flow control assembly is slidably arranged in the outer shell assembly, and a return spring 1 is arranged between the sliding flow control assembly and the outer shell assembly;

[0045] The outer shell assembly includes an upper joint assembly 2, and the sliding flow control assembly includes a flow control upper sleeve 3. The outer wall of the flow control upper sleeve 3 is provided with a plurality of first liquid inlet holes 301 connected with the inner hole thereof. When the reset spring 1 is in a free state, the plurality of first liquid inlet holes 301 are all connected with the liquid inlet end of the upper joint assembly 2.

[0046] An airbag 4 is provided in the upper joint assembly 2 . When the airbag 4 is inflated, the sliding flow control component slides along the inner wall of the outer shell component to block part or all of the first liquid inlet hole 301 from the liquid inlet end of the upper joint assembly 2 .

[0047] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the lower end of the upper joint assembly 2 is provided with a first sliding hole 201 along the axial direction, and the upper end of the upper joint assembly 2 is provided with a second liquid inlet hole 202 along the axial direction;

[0048] The first sliding hole 201 is connected to the second liquid inlet hole 202, the diameter of the second liquid inlet hole 202 is larger than the diameter of the first sliding hole 201, the flow control upper sleeve 3 is slidably set in the first sliding hole 201, and when the reset spring 1 is in a free state, several of the first liquid inlet holes 301 are connected to the second liquid inlet hole 202.

[0049] In this embodiment, if Fig.11 The figure shows a schematic diagram of the installation of the flow control device. When annular space loss occurs, the number of the first liquid inlet holes 301 connected to the second liquid inlet hole 202 is controlled, thereby changing the cross-sectional area of ​​the flow channel so that the fluid is subjected to a certain resistance when passing through, thereby reducing the flow velocity and flow rate of the fluid and achieving flow control. Specifically, when annular space loss occurs, the airbag 4 is inflated to drive the sliding flow control assembly to move, thereby controlling the flow rate and speed of the fluid. At this time, the kinetic energy of the liquid increases and the static energy decreases. According to Bernoulli's theorem, when the kinetic energy increases and the static energy decreases, the total energy remains unchanged. Therefore, the energy conversion that occurs when the drilling fluid inside the drill string passes through the flow control device is manifested as a pressure drop, thereby reducing the possibility of negative pressure generation and increasing the reliability of the MWD signal.

[0050] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the upper end of the flow control upper sleeve 3 is connected to the limiting sleeve 5;

[0051] The outer diameter of the limiting sleeve 5 is larger than the outer diameter of the flow control upper sleeve 3 , and the inner diameter of the limiting sleeve 5 is smaller than the inner diameter of the flow control upper sleeve 3 .

[0052] In this embodiment, by setting the outer diameter of the limiting sleeve 5 to be larger than the outer diameter of the flow control upper sleeve 3, when the sliding flow control assembly moves to the bottom of its stroke, the lower end of the limiting sleeve 5 abuts against the upper end surface of the first sliding hole 201, thereby limiting the sliding flow control assembly. In this embodiment, by setting the inner diameter of the limiting sleeve 5 to be smaller than the inner diameter of the flow control upper sleeve 3, when part of the first liquid inlet hole 301 is blocked from the second liquid inlet hole 202, the flow rate of drilling fluid flowing through the inner hole of the flow control upper sleeve 3 is reduced.

[0053] like Figure 1 , Figure 2 and Figure 6 As shown, a plurality of the first liquid inlet holes 301 are arranged in an annular array on a plurality of annular planes in the axial direction of the flow control upper sleeve 3 .

[0054] In this embodiment, the number of the first liquid inlet holes 301 is 8, and they are arranged in an array in two annular planes.

[0055] like Figure 1 , Figure 2 and Figure 7 As shown, the outer shell assembly also includes an intermediate joint sleeve 6 and a lower joint assembly 7;

[0056] One end of the middle joint sleeve 6 is connected to the outer wall of the middle part of the upper joint assembly 2, and the other end of the middle joint sleeve 6 is connected to one end of the lower joint assembly 7. A second sliding hole 701 along the axial direction is provided in the lower joint assembly 7.

[0057] In this embodiment, internal threads are provided at both the upper and lower ends of the middle joint sleeve 6, the diameter of the middle part of the upper joint assembly 2 is reduced, and external threads are provided on the outer wall of the middle part, and external threads are also provided on the outer wall of the upper end of the lower joint assembly 7. The middle joint sleeve 6 is threadedly connected to the upper joint assembly 2 and the lower joint assembly 7.

[0058] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the lower end of the flow control upper sleeve 3 is connected to the flow control lower sleeve 8, and the flow control lower sleeve 8 is slidably disposed in the second sliding hole 701;

[0059] A limit flange 801 is provided at the upper end of the flow control lower sleeve 8, and the limit flange 801 is located in the piston chamber 601 between the upper joint assembly 2 and the lower joint assembly 7. The outer wall of the limit flange 801 slides along the inner wall of the middle joint sleeve 6, and the reset spring 1 is provided between the limit flange 801 and the lower joint assembly 7.

[0060] In this embodiment, the outer wall of the limiting flange 801 and the inner wall of the middle joint sleeve 6 are slidably sealed.

[0061] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, a placement groove 203 is provided on the outer wall of the upper joint assembly 2, and the placement groove 203 and the inner wall of the middle joint sleeve 6 form a placement cavity for placing the airbag 4;

[0062] The upper joint assembly 2 is provided with an air inlet channel 204 connecting the outer wall of the upper joint assembly 2 with the airbag 4 in the placement chamber, a first flow channel 205 for connecting the placement chamber with the piston chamber 601, a second flow channel 206 for connecting the piston chamber 601 with the outer wall of the upper joint assembly 2, and a third flow channel 207 for connecting the placement chamber with the second flow channel 206.

[0063] like Figure 1 and Figure 3 As shown, a one-way pressure balancing valve 9 is disposed in the second flow channel 206 , and a one-way charging valve 10 is disposed in the air inlet channel 204 .

[0064] In this embodiment, the drilling fluid can only be transmitted from the outer wall of the upper joint assembly 2 to the inside by setting the one-way pressure balance valve 9, and the gas can only be transmitted to the airbag 4 by setting the one-way inflation valve 10. As an embodiment of the present application, the one-way pressure balance valve 9 and the one-way inflation valve 10 both include a limit screw and a spring, a sliding hole is set on the pipe wall at the corner position of the second flow channel 206 and the air inlet channel 204, the limit screw is slidably set in the sliding hole, and a spring is set between the limit screw and the upper end of the sliding hole, and when the spring is in a free state, the nut of the limit screw blocks the flow channel or the air channel.

[0065] like Figure 1 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, a third liquid inlet 602 communicating with the piston cavity 601 is provided on the outer wall of the intermediate joint sleeve 6 , and the third liquid inlet 602 is located at the lower part of the piston cavity 601 .

[0066] In this embodiment, the number of the third liquid inlets 602 is four, and the four third liquid inlets 602 are distributed in a circular array on the outer wall of the middle joint sleeve 6 at the lower part of the piston cavity 601 . The drilling fluid can enter or discharge the piston cavity 601 through the third liquid inlets 602 .

[0067] like Figure 1 , Figure 3 and Figure 7As shown, O-rings 11 are provided between the upper joint assembly 2 and the flow control upper sleeve 3 and between the lower joint assembly 7 and the flow control lower sleeve 8 .

[0068] In this embodiment, annular grooves are processed on the inner rings of the upper joint assembly 2 and the lower joint assembly 7 for installing O-rings.

[0069] like Figure 8 , Fig. 9 and Fig.10 Shown are the three working processes of the flow control device when well leakage occurs.

[0070] like Figure 8 As shown, when the drilling work is carried out normally, the entire drilling fluid circulation is equivalent to a closed system. Under the pressure of the static liquid column in the annulus, the one-way pressure balance valve 9 is opened, and the drilling fluid enters the flow control device from the valve port of the one-way pressure balance valve (the outer wall position of the upper joint assembly 2), and enters the placement cavity where the airbag 4 is located through the second flow channel 206 and the third flow channel 207 in turn. Similarly, the drilling fluid enters the piston cavity 601 from the third hole 602 in the four directions of the side of the middle joint assembly 2. Under the pressure of the drilling fluid and the elastic force of the return spring 1, the limit flange 801 always maintains the top state, so that the 8 first liquid inlet holes 301 at the top of the flow control upper sleeve 3 all leak out.

[0071] like Fig. 9 As shown, when a leak occurs in the wellbore, the drilling fluid seeps into the formation, the pressure of the static liquid column in the annulus decreases, thereby generating negative pressure, causing the drilling fluid in the drill string to be sucked downward, affecting the operation of the MWD. ​​At this time, the one-way inflation valve 10 is opened, and the gas enters the airbag 4 to expand it. Due to the action of the one-way pressure balance valve 9, the drilling fluid at the airbag cannot be discharged from the incoming channel, and the drilling fluid is squeezed and discharged downward along the first flow channel 205. The return spring 1 in the flow control device is compressed, and the drilling fluid in the piston chamber is discharged from the third liquid hole 602, driving the flow control upper sleeve 3 and the flow control lower sleeve 8 to move downward, closing the upper 4 of the 8 first liquid inlet holes 301, and changing the size of the drilling fluid flow area.

[0072] like Fig.10 As shown, the airbag 4 is continuously inflated and only expands to the maximum until the flow control upper sleeve 3 and the flow control lower sleeve 8 move to the bottom, and the eight first liquid inlet holes 301 of the flow control upper sleeve 3 are all closed. At this time, the drilling fluid pressure passing through the flow control device in the drill tool becomes smaller and is balanced with the annular pressure, so that the possibility of negative pressure generation is reduced, and the drilling fluid passes through the MWD continuously and stably, thereby achieving the stability of MWD signal transmission.

[0073] The present application controls the up and down movement of the sliding flow control component in the flow control device by the volume expansion of the airbag inflation, and changes the cross-sectional area of ​​the flow channel by controlling the number of the first liquid inlet holes 301 connected to the second liquid inlet hole 202. When a leak occurs, the flow control device works faster and consumes less energy. It has a simple structure and can adapt to high temperature and high pressure conditions underground without failure. The working principle of the flow control device of the present application is based on the Bernoulli principle and the continuity equation. When the fluid passes through the flow control device, the reduction in the cross-sectional area of ​​the pipeline causes the flow rate to increase. At this time, the kinetic energy of the liquid increases, and the total energy remains unchanged. Therefore, the energy conversion that occurs when the liquid passes through the flow control device is manifested as a pressure drop.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A drilling fluid flow control device for improving the reliability of MWD signals, characterized in that: It comprises an outer shell component, a sliding flow control component is slidably arranged inside the outer shell component, and a return spring (1) is arranged between the sliding flow control component and the outer shell component; The outer shell assembly comprises an upper joint assembly (2), the sliding flow control assembly comprises an upper flow control sleeve (3), a plurality of first liquid inlet holes (301) connected to the inner hole of the upper flow control sleeve (3) are provided on the outer wall of the upper flow control sleeve (3), and when the return spring (1) is in a free state, the plurality of first liquid inlet holes (301) are all connected to the liquid inlet end of the upper joint assembly (2); An airbag (4) is arranged in the upper joint assembly (2). When the airbag (4) is inflated, the sliding flow control component slides along the inner wall of the outer shell component, so that part or all of the first liquid inlet hole (301) is blocked from the liquid inlet end of the upper joint assembly (2).

2. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 1, characterized in that: The lower end of the upper joint assembly (2) is provided with a first sliding hole (201) along the axial direction, and the upper end of the upper joint assembly (2) is provided with a second liquid inlet hole (202) along the axial direction; The first sliding hole (201) is connected to the second liquid inlet hole (202); the diameter of the second liquid inlet hole (202) is larger than the diameter of the first sliding hole (201); the flow control upper sleeve (3) is slidably arranged in the first sliding hole (201); when the reset spring (1) is in a free state, a plurality of the first liquid inlet holes (301) are connected to the second liquid inlet hole (202).

3. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 1, characterized in that: The upper end of the flow control upper sleeve (3) is connected to a limiting sleeve (5); The outer diameter of the limiting sleeve (5) is greater than the outer diameter of the flow control upper sleeve (3), and the inner diameter of the limiting sleeve (5) is smaller than the inner diameter of the flow control upper sleeve (3).

4. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 1, characterized in that: A plurality of the first liquid inlet holes (301) are arranged in an annular array on a plurality of annular planes in the axial direction of the flow control upper sleeve (3).

5. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 1, characterized in that: The outer shell assembly also includes an intermediate joint sleeve (6) and a lower joint assembly (7); One end of the middle joint sleeve (6) is connected to the outer wall of the middle part of the upper joint assembly (2), and the other end of the middle joint sleeve (6) is connected to one end of the lower joint assembly (7), and a second sliding hole (701) along the axial direction is provided in the lower joint assembly (7).

6. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 5, characterized in that: The lower end of the flow control upper sleeve (3) is connected to a flow control lower sleeve (8), and the flow control lower sleeve (8) is slidably disposed in the second sliding hole (701); A limit flange (801) is provided at the upper end of the flow control lower sleeve (8), and the limit flange (801) is located in the piston chamber (601) between the upper joint assembly (2) and the lower joint assembly (7). The outer wall of the limit flange (801) slides along the inner wall of the middle joint sleeve (6), and the return spring (1) is provided between the limit flange (801) and the lower joint assembly (7).

7. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 6, characterized in that: A placement groove (203) is provided on the outer wall of the upper joint assembly (2), and the placement groove (203) and the inner wall of the middle joint sleeve (6) form a placement cavity for placing the airbag (4); The upper joint assembly (2) is provided with an air inlet passage (204) connecting the outer wall of the upper joint assembly (2) and the airbag (4) in the placement chamber, a first flow passage (205) for connecting the placement chamber and the piston chamber (601), a second flow passage (206) for connecting the piston chamber (601) and the outer wall of the upper joint assembly (2), and a third flow passage (207) for connecting the placement chamber and the second flow passage (206).

8. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 7, characterized in that: A one-way pressure balancing valve (9) is arranged in the second flow channel (206), and a one-way inflation valve (10) is arranged in the air inlet channel (204).

9. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 6, characterized in that: A third liquid inlet (602) communicating with the piston chamber (601) is provided on the outer wall of the intermediate joint sleeve (6), and the third liquid inlet (602) is located at the lower part of the piston chamber (601).

10. A drilling fluid flow control device for improving the reliability of MWD signals according to claim 5, characterized in that: O-type sealing rings (11) are provided between the upper joint assembly (2) and the flow control upper sleeve (3), and between the lower joint assembly (7) and the flow control lower sleeve (8).

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