Drilling fluid driven position feedback hydraulic servo system

Abstract

The present application relates to a kind of drilling fluid driven position feedback hydraulic servo system, it is related to rotary steerable drilling equipment technical field, for solving the problem that piston processing is difficult and sealing performance is not good.It includes: flow distribution mechanism, it is arranged in wellbore, multiple cylindrical piston cavities are arranged at intervals in it, flow distribution mechanism is simultaneously communicated with the center high-pressure passage of upper portion and the annular low-pressure passage outside;And servo piston mechanism, including multiple piston rod assemblies, one end is connected with the multiple transmission blocks of the push-in rotary steerable drilling tool one by one, the other end is connected with the multiple adjusting wedge blocks of the push-in rotary steerable drilling tool one by one.Set flow distribution mechanism to the high-pressure drilling fluid in the center high-pressure passage of upper portion of drill string is shunted, and its space is reasonably utilized, multiple cylindrical piston cavities are arranged to correspond to set multiple cylindrical pistons.Cylindrical piston is easy to process and sealing effect is good, reduce the risk of internal leakage of servo piston mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rotary steerable drilling equipment, in particular to a drilling fluid driven position feedback hydraulic servo system. BACKGROUND

[0002] Rotary steerable drilling technology is an advanced well trajectory control technology in the field of oil drilling at home and abroad. Among them, the pointing rotary steerable system can better control the inclination and azimuth, and the drilled wellbore is smooth, and the wellbore quality and safety are high.

[0003] Chinese patent CN113073939A discloses an inner pushing type rotary steerable drilling tool, which comprises a shell body, an adjusting mechanism, a hydraulic drive mechanism and a drill bit seat adjusting mechanism. The drill bit seat adjusting mechanism comprises adjusting wedges, an adjusting rod, an adjusting ball seat and a drill bit seat. The adjusting ball seat is sleeved on the upper end of the adjusting rod and located in the central space surrounded by the three adjusting wedges. A rotating fulcrum is arranged between the adjusting rod and the shell body. The lower part of the adjusting rod is provided with the drill bit seat. The adjusting mechanism comprises a speed regulating motor, a gear set, a transmission screw, a transmission block and a control valve. The motor drives the gear set and the transmission screw to rotate and controls the rotation speed and direction. The transmission block is threadedly connected with the transmission screw to form a screw nut mechanism. The transmission block is connected with the control valve. Three groups of adjusting mechanisms and hydraulic drive mechanisms are arranged in the inner ring circumference of the shell body. During operation, the adjusting mechanism changes the rotation speed and direction of the speed regulating motor to control the axial displacement of the transmission block. The transmission block drives the control valve to control the axial displacement of the corresponding hydraulic drive mechanism. The hydraulic drive mechanism is connected with the corresponding adjusting wedge through a pull rod to drive the adjusting wedge to move periodically, thereby changing the azimuth angle of the drill bit seat relative to the ground and the structural angle of the drill bit seat relative to the shell body, and realizing rotary steerable drilling.

[0004] However, the hydraulic drive mechanism in the above technical solution is limited by its own structure and must use a sector-shaped piston. However, the sector-shaped cross section is a non-standard cross section, and the general sealing method is also based on a circular cross section, which is not completely suitable for the sector shape. At the same time, it is difficult to ensure the machining precision of the sector shape due to the complex shape of the sector, and the machining precision and tolerance of the piston and the piston cylinder are the main factors affecting the sealing performance. Therefore, the sealing performance of the sector-shaped piston is not good, which seriously affects the performance of the hydraulic drive mechanism.

[0005] Therefore, there is a problem of difficult piston machining and poor sealing performance in the prior art. SUMMARY

[0006] The present application provides a drilling fluid driven position feedback hydraulic servo system to solve the problem of difficult piston machining and poor sealing performance.

[0007] The present application provides a drilling fluid driven position feedback hydraulic servo system, an inner push type rotary steerable drilling tool, which comprises: a flow distribution mechanism arranged in a wellbore, a plurality of cylindrical piston cavities are arranged in the flow distribution mechanism, the flow distribution mechanism is in communication with a central high-pressure passage at the upper part and an annular low-pressure passage at the outer part; and a servo piston mechanism comprising a plurality of piston rod assemblies, one end of each of the piston rod assemblies is connected to a plurality of transmission blocks of the inner push type rotary steerable drilling tool in one-to-one correspondence, and the other end of each of the piston rod assemblies is connected to a plurality of adjusting wedge blocks of the inner push type rotary steerable drilling tool in one-to-one correspondence; wherein the piston rod assembly comprises a cylindrical piston, a plurality of cylindrical pistons are arranged in the plurality of cylindrical piston cavities in one-to-one correspondence, and the plurality of transmission blocks can adjust the conduction mode of the high-pressure passage and the low-pressure passage with the plurality of cylindrical piston cavities to control the action of the servo piston mechanism, so as to adjust the spatial position of the surrounding structure center defined by the plurality of adjusting wedge blocks.

[0008] In one embodiment, the flow distribution mechanism comprises: an outer shell arranged in the wellbore; and a flow collecting disc arranged at the bottom of the outer shell; and a flow distribution cylinder sleeve arranged on the flow collecting disc; and a separation disc arranged on the flow distribution cylinder sleeve; and an isolation sleeve assembly arranged on the separation disc; wherein the plurality of piston rod assemblies are sequentially arranged on the isolation sleeve assembly, the separation disc, the flow distribution cylinder sleeve and the flow collecting disc, the flow distribution cylinder sleeve, the separation disc and the flow collecting disc define a plurality of cylindrical piston cavities arranged along the circumference of the flow distribution mechanism and a high-pressure flow channel, the isolation sleeve assembly has a high-pressure chamber and a low-pressure chamber which is not in communication with the high-pressure chamber, the high-pressure chamber is in communication with the high-pressure passage, the high-pressure flow channel and the plurality of cylindrical piston cavities, the low-pressure chamber is in communication with the low-pressure passage and the plurality of cylindrical piston cavities, and the communication positions of the cylindrical piston cavities with the high-pressure chamber and the low-pressure chamber are located on both sides of the corresponding cylindrical pistons.

[0009] In one embodiment, the isolation sleeve assembly comprises: a low-pressure isolation sleeve arranged on the separation disc; and a high-pressure isolation sleeve provided with a high-pressure chamber, the high-pressure isolation sleeve being arranged on the low-pressure isolation sleeve; wherein the low-pressure isolation sleeve and the high-pressure isolation sleeve define a low-pressure chamber.

[0010] In one embodiment, the cylindrical piston divides the cylindrical piston cavity into an upper isolation chamber and a lower isolation chamber, and the piston rod assembly further comprises:

[0011] The servo valve sleeve is arranged on the isolation sleeve assembly and is provided with an overflow port at one end, and the servo valve sleeve is connected with the transmission block; and the servo valve spool is arranged on the collecting disc, the distribution cylinder sleeve and the separation disc, one end of the servo valve spool extends into the servo valve sleeve from the other end of the servo valve sleeve and is arranged in the servo valve sleeve in a sliding mode, and the other end of the servo valve spool extends out of the collecting disc and is connected with the adjusting wedge, and the cylindrical piston sleeve is arranged on the outer periphery of the servo valve spool; wherein the servo valve spool is provided with a first chamber and a second chamber, the relative sliding position of the adjusting servo valve sleeve and the servo valve spool is adjusted, the first chamber can conduct the high-pressure chamber and the upper isolation chamber, the second chamber can conduct the low-pressure chamber and the lower isolation chamber, or the first chamber can conduct the low-pressure chamber and the upper isolation chamber, and the second chamber can conduct the high-pressure chamber and the lower isolation chamber.

[0012] In one embodiment, an annular step is arranged on the servo valve spool, and the outer periphery of the annular step is sleeved with the cylindrical piston.

[0013] In one embodiment, six openings are arranged on the outer periphery of the servo valve spool in the first direction in sequence and at intervals, wherein the first opening a1, the second opening a2 and the third opening a3 are communicated with the first chamber, the fourth opening a4, the fifth opening a5 and the sixth opening a6 are communicated with the second chamber, the fourth opening a4, the first opening a1, the second opening a2, the fifth opening a5, the third opening a3 and the sixth opening a6 are sequentially and interval arranged in the first direction, and the third opening a3 and the sixth opening a6 are arranged on the two sides of the cylindrical piston respectively; four communication ports are arranged on the outer periphery of the servo valve sleeve in the first direction at intervals, wherein the third communication port b3, the first communication port b1, the second communication port b2 and the fourth communication port b4 are sequentially and interval arranged in the first direction; when the first opening a1 is communicated with the first communication port b1, the fifth opening a5 is communicated with the fourth communication port b4, when the fourth opening a4 is communicated with the third communication port b3, the second opening a2 is communicated with the second communication port b2.

[0014] In one embodiment, four annular grooves are arranged on the outer periphery of the servo valve spool at intervals, and the first opening a1, the second opening a2, the fourth opening a4 and the fifth opening a5 are arranged on the annular grooves c1 to c4 in one-to-one correspondence; when the lower side of the first opening a1 is aligned with the upper side of the first annular groove c1, the upper side of the second opening a2 is aligned with the lower side of the second annular groove c2, the upper side of the fourth opening a4 is aligned with the lower side of the third annular groove c3, and the lower side of the fifth opening a5 is aligned with the upper side of the fourth annular groove c4.

[0015] In one embodiment, the annular step is arranged eccentrically with the servo valve spool.

[0016] In one embodiment, the first flow collection runner and the plurality of first flow distribution runners are arranged in the flow collection disc, the plurality of second flow distribution runners are arranged in the flow distribution cylinder in one-to-one correspondence with the plurality of first flow distribution runners, the second flow collection runner and the plurality of third flow distribution runners are arranged in the flow separation disc, the plurality of third flow distribution runners are connected to the plurality of second flow distribution runners in one-to-one correspondence, and the first flow collection runner, the plurality of first flow distribution runners, the plurality of second flow distribution runners, the plurality of third flow distribution runners and the second flow collection runner form a high-pressure flow channel.

[0017] In one embodiment, the plurality of first radial communication channels are arranged in the flow collection disc, one end of each of the plurality of first radial communication channels is in communication with the first flow collection runner, and the other end of each of the plurality of first radial communication channels is in communication with the plurality of first flow distribution runners in one-to-one correspondence, and / or the plurality of second radial communication channels are arranged in the flow separation disc, one end of each of the plurality of second radial communication channels is in communication with the second flow collection runner, and the other end of each of the plurality of second radial communication channels is in communication with the plurality of third flow distribution runners in one-to-one correspondence.

[0018] Compared with the prior art, the advantages of the present application are that the high-pressure drilling fluid in the upper center high-pressure channel of the drill string is distributed by the flow distribution mechanism, and the space is reasonably utilized, and a plurality of cylindrical piston cavities are arranged to correspond to a plurality of cylindrical pistons. The cylindrical piston with a circular cross-section is easy to process and has good sealing effect, which reduces the risk of internal leakage of the servo piston mechanism, thereby avoiding the problems of processing difficulty and poor sealing performance caused by the fan-shaped piston in the prior art. Furthermore, the energy conversion efficiency of the high-pressure drilling fluid is improved to ensure that the position feedback hydraulic servo system driven by the drilling fluid can work efficiently and stably. BRIEF DESCRIPTION OF DRAWINGS

[0019] In the following, the present application will be described in more detail on the basis of embodiments and with reference to the accompanying drawings.

[0020] Figure 1 is a main sectional view of the position feedback hydraulic servo system driven by the drilling fluid in the embodiment of the present application;

[0021] Figure 2 is Figure 1 is a sectional view of the position feedback hydraulic servo system driven by the drilling fluid in the embodiment of the present application at A-A;

[0022] Figure 3 is Figure 1 is a sectional view of the position feedback hydraulic servo system driven by the drilling fluid in the embodiment of the present application at B-B;

[0023] Figure 4 is Figure 1 is a sectional view of the position feedback hydraulic servo system driven by the drilling fluid in the embodiment of the present application at C-C;

[0024] Figure 5 isFigure 1 Assembly view of the middle housing, the manifold, the shunt cylinder sleeve and the separation disc;

[0025] Figure 6 Is Figure 1 Perspective view of the middle piston rod assembly;

[0026] Figure 7 Is Figure 6 Perspective view of the middle servo valve spool push rod;

[0027] Figure 8 Is Figure 6 Perspective view of the middle servo valve spool push rod from another angle;

[0028] Figure 9 Is Figure 6 Half cut view of the middle servo valve spool push rod;

[0029] Figure 10 Is Figure 6 Half cut view of the middle servo valve sleeve;

[0030] Figure 11 Is Figure 1 Perspective view of the middle separation disc;

[0031] Figure 12 Is Figure 1 Perspective view of the middle separation disc from another angle;

[0032] Figure 13 Is Figure 1 Perspective view of the middle shunt cylinder sleeve;

[0033] Figure 14 Is Figure 1 Perspective view of the middle manifold;

[0034] Figure 15 Is Figure 1 Perspective view of the middle manifold from another angle;

[0035] Figure 16 Is Figure 1 Perspective view of the high pressure isolation sleeve in the middle;

[0036] Figure 17 Is Figure 1 Perspective view of the low pressure isolation sleeve in the middle.

[0037] Reference signs:

[0038] 10, flow distribution mechanism; 11, outer housing; 12, manifold; 121, first manifold channel; 122, first sub-manifold channel; 123, first radial communication channel; 13, sub-manifold cylinder; 131, second sub-manifold channel; 14, separation disc; 141, second manifold channel; 142, third sub-manifold channel; 143, second radial communication channel; 15, isolation sleeve assembly; 151, high-pressure isolation sleeve; 1511, high-pressure chamber; 152, low-pressure isolation sleeve; 1521, low-pressure chamber; 20, servo piston mechanism; 21, piston rod assembly; 211, servo valve sleeve; 2111, overflow port; 212, cylindrical piston; 213, servo valve core push rod; 2131, first chamber; 2132, second chamber; 2133, sealing end cover; 214, annular step; 30, cylindrical piston cavity; 31, upper isolation cavity; 32, lower isolation cavity; 40, high-pressure flow channel. DETAILED DESCRIPTION

[0039] The application will be further described below with reference to the accompanying drawings.

[0040] It should be noted that the drilling fluid driven position feedback hydraulic servo system in the present application is mainly used for an internal push type rotary steerable drilling tool. The internal push type rotary steerable drilling tool is connected with a drill string at the upper part and connected with a drill bit at the lower part. High-pressure drilling fluid passes through the inside of the internal push type rotary steerable drilling tool, and low-pressure drilling fluid passes through the outside of the internal push type rotary steerable drilling tool. The drilling fluid driven position feedback hydraulic servo system is a functional unit of the internal push type rotary steerable drilling tool. The upper end of the drilling fluid driven position feedback hydraulic servo system is connected with a plurality of transmission blocks of the internal push type rotary steerable drilling tool, and the lower end of the drilling fluid driven position feedback hydraulic servo system is connected with a plurality of adjustment wedges of the internal push type rotary steerable drilling tool. The drilling fluid driven position feedback hydraulic servo system is driven by the transmission blocks to work to accurately control the spatial position of the surrounding structure center defined by the adjustment wedges, so as to change the azimuth angle of the drill bit seat relative to the ground and the structural angle of the drill bit seat relative to the outer housing body, and then realize rotary steering drilling. The specific structure and connection relationship of other parts of the internal push type rotary steerable drilling tool are the prior art, and can be specifically referred to Chinese patent CN113073939A, which will not be described here.

[0041] As Figures 1 to 4As shown, the present application provides a drilling fluid driven position feedback hydraulic servo system, which comprises a flow distribution mechanism 10 and a servo piston mechanism 20. The flow distribution mechanism 10 is arranged in the wellbore, and a plurality of cylindrical piston cavities 30 are arranged in it at intervals. The flow distribution mechanism 10 is in communication with the upper central high-pressure channel and the outer annular low-pressure channel at the same time. The servo piston mechanism 20 comprises a plurality of piston rod assemblies 21, one end of which is connected to a plurality of transmission blocks of the push-in rotary steerable drilling tool in one-to-one correspondence, and the other end is connected to a plurality of adjustment wedge blocks of the push-in rotary steerable drilling tool in one-to-one correspondence. The piston rod assembly 21 comprises a cylindrical piston 212, and a plurality of cylindrical pistons 212 are arranged in the plurality of cylindrical piston cavities 30 in one-to-one correspondence. The transmission blocks can adjust the conduction mode of the high-pressure channel and the low-pressure channel to the plurality of cylindrical piston cavities 30 to control the action of the servo piston mechanism 20, so as to adjust the spatial position of the surrounding structure center defined by the plurality of adjustment wedge blocks.

[0042] In the above arrangement, the flow distribution mechanism 10 is arranged to distribute the high-pressure drilling fluid in the upper central high-pressure channel of the drill string, and reasonably utilize the space to arrange a plurality of cylindrical piston cavities 30 to correspond to a plurality of cylindrical pistons 212. The plurality of cylindrical pistons 212 not only meet the requirement of large piston cross-sectional area, but also simplify the design and processing compared with the sector-shaped piston, improve the precision, and increase the sealing reliability. In this way, the cylindrical piston 212 with a circular cross-section is easy to process and has good sealing effect, which reduces the risk of internal leakage of the servo piston mechanism 20, thereby avoiding the problems of processing difficulty and poor sealing performance caused by the sector-shaped piston in the prior art. Furthermore, the energy conversion efficiency of the high-pressure drilling fluid is improved to ensure that the drilling fluid driven position feedback hydraulic servo system can work efficiently and stably.

[0043] Specifically, as shown in the drawings, Figure 5 In one embodiment, the flow distribution mechanism 10 comprises an outer housing 11, a flow collection disc 12, a flow distribution cylinder sleeve 13, a separation disc 14, and an isolation sleeve assembly 15.

[0044] The outer casing 11 is disposed inside the wellbore; the collector plate 12 is disposed at the bottom of the outer casing 11; the distributor cylinder liner 13 is disposed on the collector plate 12; the separator plate 14 is disposed on the distributor cylinder liner 13; and the isolation sleeve assembly 15 is disposed on the separator plate 14. Multiple piston rod assemblies 21 are sequentially disposed on the isolation sleeve assembly 15, the separator plate 14, the distributor cylinder liner 13, and the collector plate 12. The distributor cylinder liner 13, the separator plate 14, and the collector plate 12 define multiple cylindrical piston chambers 30 spaced circumferentially along the distribution mechanism 10 and a high-pressure flow channel 40. The isolation sleeve assembly 15 has a high-pressure chamber 1511 and a low-pressure chamber 1521 that is not connected to the high-pressure chamber 1511. The high-pressure chamber 1511 is connected to the high-pressure channel, the high-pressure flow channel 40 is connected to the multiple piston rod assemblies 21, and the low-pressure chamber 1521 is connected to the low-pressure channel. The connection points between the cylindrical piston cavity 30 and the high-pressure chamber 1511 and the low-pressure chamber 1521 are located on both sides of the corresponding cylindrical piston 212.

[0045] In the above configuration, the high-pressure chamber 1511 is used to guide a portion of the high-pressure drilling fluid from the high-pressure channel at the top center of the drill string into the high-pressure flow channel 40, facilitating its introduction into the next connecting component. Simultaneously, the high-pressure chamber 1511 can guide another portion of the high-pressure drilling fluid into the piston rod assembly 21, providing hydraulic power to the piston rod assembly 21, i.e., providing hydraulic power to the drilling fluid-driven position feedback hydraulic servo system. This ensures that the drilling fluid-driven position feedback hydraulic servo system can operate normally, enabling spatial position adjustment of the enclosure center.

[0046] It should be noted that the connections between the cylindrical piston cavity 30 and the high-pressure chamber 1511 and low-pressure chamber 1521 are located on both sides of the corresponding cylindrical piston 212. This allows the fluid on both sides of the cylindrical piston 212 within the cylindrical piston cavity 30 to flow normally, and the cylindrical piston 212 to extend and retract normally within the cylindrical piston cavity 30. This ensures the proper functioning of the drilling fluid-driven position feedback hydraulic servo system.

[0047] Specifically, such as Figures 2 to 4 As shown, in one embodiment, the flow distribution mechanism 10 is provided with three cylindrical piston chambers 30, which are evenly spaced along the circumference of the flow distribution mechanism 10. Correspondingly, the servo piston mechanism 20 includes three piston rod assemblies 21, which are arranged one-to-one in the three cylindrical piston chambers 30.

[0048] In alternative embodiments not shown in the accompanying drawings, two, four, or more cylindrical piston chambers 30 may also be provided.

[0049] It should be noted that the space position of the center of the surrounding structure defined by the three adjusting wedges is accurately controlled by hydraulic servo control to change the azimuth angle of the bit seat relative to the ground and the structural angle relative to the housing body, thereby realizing rotary steerable drilling.

[0050] Specifically, as shown in Figure 5 、 Figure 16 and Figure 17 , in one embodiment, the isolation sleeve assembly 15 includes a low-pressure isolation sleeve 152 and a high-pressure isolation sleeve 151. The low-pressure isolation sleeve 152 is arranged on the separation disc 14, the high-pressure isolation sleeve 151 is provided with a high-pressure chamber 1511, and the high-pressure isolation sleeve 151 is arranged on the low-pressure isolation sleeve 152; the low-pressure isolation sleeve 152 and the high-pressure isolation sleeve 151 define a low-pressure chamber 1521.

[0051] Specifically, as shown in Figure 1 and Figure 5 , in one embodiment, the cylindrical piston separates the cylindrical piston cavity 30 into an upper isolation cavity 31 and a lower isolation cavity 32.

[0052] Specifically, as shown in Figures 1 to 4 , in one embodiment, the piston rod assembly 21 further includes a servo valve sleeve 211 and a servo valve core push rod 213. The servo valve sleeve 211 is arranged on the isolation sleeve assembly 15, one end of which is provided with an overflow port 2111, and the servo valve sleeve 211 is connected with the transmission block; the servo valve core push rod 213 is arranged on the manifold disc 12, the shunt cylinder sleeve 13 and the separation disc 14, one end of which extends from the other end of the servo valve sleeve 211 and is slidably arranged in the servo valve sleeve 211, and the other end extends from the manifold disc 12 and is connected with the adjusting wedge, and the cylindrical piston 212 is arranged on the outer periphery of the servo valve core push rod 213. The servo valve core push rod 213 is provided with a first chamber 2131 and a second chamber 2132, and the relative sliding position of the servo valve sleeve 211 and the servo valve core push rod 213 is adjusted, the first chamber 2131 can communicate the high-pressure chamber 1511 with the upper isolation cavity 31, and the second chamber 2132 can communicate the low-pressure chamber 1521 with the lower isolation cavity 32, or the first chamber 2131 can communicate the low-pressure chamber 1521 with the upper isolation cavity 31, and the second chamber 2132 can communicate the high-pressure chamber 1511 with the lower isolation cavity 32.

[0053] It should be noted that when the first chamber 2131 can conduct the high-pressure chamber 1511 and the upper isolation chamber 31, and the second chamber 2132 can conduct the low-pressure chamber 1521 and the lower isolation chamber 32, the cylindrical piston 212 slides downward. When the first chamber 2131 conducts the low-pressure chamber 1521 and the upper isolation chamber 31, and the second chamber 2132 conducts the high-pressure chamber 1511 and the lower isolation chamber 32, the cylindrical piston 212 slides upward. The upper end of the servo valve spool 213 is provided with a sealing end cover 2133, which is used to seal the opening of the first chamber 2131 and the second chamber 2132.

[0054] In the above arrangement, sliding the plurality of transmission blocks can adjust the relative sliding position between the servo valve sleeve 211 and the servo valve spool 213, thereby adjusting the conduction mode of the high-pressure channel and the low-pressure channel to the plurality of cylindrical piston chambers 30 to control the action of the servo piston mechanism 20, thereby adjusting the spatial position of the surrounding structure center defined by the plurality of adjusting wedge blocks.

[0055] Specifically, as shown in the drawings, Figures 6 to 10 in one embodiment, six openings are sequentially and spaced apart on the outer periphery of the servo valve spool 213 in the first direction, wherein the first opening a1, the second opening a2 and the third opening a3 are in communication with the first chamber 2131, the fourth opening a4, the fifth opening a5 and the sixth opening a6 are in communication with the second chamber 2132, the fourth opening a4, the first opening a1, the second opening a2, the fifth opening a5, the third opening a3 and the sixth opening a6 are sequentially and spaced apart in the first direction, and the third opening a3 and the sixth opening a6 are respectively arranged on both sides of the cylindrical piston 212; four communication ports are spaced apart on the outer periphery of the servo valve sleeve 211 in the first direction, wherein the third communication port b3, the first communication port b1, the second communication port b2 and the fourth communication port b4 are sequentially and spaced apart in the first direction; when the first opening a1 is in communication with the first communication port b1, the fifth opening a5 is in communication with the fourth communication port b4, and when the fourth opening a4 is in communication with the third communication port b3, the second opening a2 is in communication with the second communication port b2.

[0056] Specifically, as shown in the drawings, Figures 6 to 9 in one embodiment, four annular grooves are spaced apart on the outer periphery of the servo valve spool 213, and the first opening a1, the second opening a2, the fourth opening a4 and the fifth opening a5 are arranged on the annular grooves c1 to c4 one by one; when the lower side of the first opening a1 is aligned with the upper side of the first annular groove c1, the upper side of the second opening a2 is aligned with the lower side of the second annular groove c2, the upper side of the fourth opening a4 is aligned with the lower side of the third annular groove c3, and the lower side of the fifth opening a5 is aligned with the upper side of the fourth annular groove c4.

[0057] It should be noted that at this time, the first chamber 2131 and the second chamber 2132 in the servo valve core push rod 213 cannot be connected with the high and low pressure flow channels (high pressure chamber 1511 and low pressure chamber 1521) of the flow distribution mechanism 10, and the cylindrical piston 212 has no fluid in and out on both sides, and the servo piston mechanism is in a balanced position.

[0058] Specifically, the flow path of the high-pressure drilling fluid in the drill string in the flow distribution mechanism 10 is as follows (refer to Figures 6 to 10 ) :

[0059] The high-pressure isolation chamber (high-pressure chamber 1511) is formed between the high-pressure isolation sleeve 151 and the low-pressure isolation sleeve 152 by the high-pressure center tube of the inner push type rotary steering drilling tool flowing into the high-pressure isolation sleeve 151. Part of the high-pressure drilling fluid in the high-pressure isolation chamber flows from the high-pressure center tube in the low-pressure isolation sleeve 152 into the center flow channel of the flow distribution disc, and then flows out through the flow distribution flow channel (second flow distribution flow channel 131 and third flow distribution flow channel 142) of the flow distribution sleeve 13 and the separation disc 14, and enters the flow distribution flow channel (first flow distribution flow channel 122) on the flow collection disc 12 to converge in the flow collection flow channel (first flow collection flow channel 121) and flow into the center tube high-pressure flow channel of the lower tool. In addition, the remaining part of the high-pressure drilling fluid in the high-pressure isolation chamber can flow into the first annular groove c1 of the servo valve core push rod 213 through the first communication port b1 on the servo valve sleeve 211, flow into the first chamber 2131 through the first opening a1 of the servo valve core push rod 213 in communication with the first annular groove c1, flow out through the third opening a3, and enter the upper chamber of the piston (upper isolation chamber 31). Or flow into the third annular groove c3 of the servo valve core push rod 213 through the third communication port b3 on the servo valve sleeve 211, flow into the second chamber 2132 through the fourth opening a4 of the servo valve core push rod 213 in communication with the third annular groove c3, flow out through the sixth opening a6, and enter the lower chamber of the piston (lower isolation chamber 32).

[0060] Specifically, the annular space between the high-pressure center tube of the low-pressure isolation sleeve 152 and the outer sidewall thereof is a low-pressure isolation chamber (low-pressure chamber 1521).

[0061] The flow path of the low-pressure drilling fluid outside the drill string in the flow distribution mechanism 10 is as follows (refer to Figures 6 to 10 ) :

[0062] The low-pressure drilling fluid in the upper chamber of the piston flows into the first chamber 2131 through the third opening a3 of the servo valve core push rod 213, and flows into the second annular groove c2 through the second opening a2 of the servo valve core push rod 213. The low-pressure fluid in the second annular groove c2 enters the low-pressure isolation chamber through the second communication port b2 of the servo valve sleeve 211. The low-pressure drilling fluid in the low-pressure isolation chamber is discharged into the annulus outside the drill string through the radial opening on the low-pressure isolation sleeve 152 and the outer shell 11; or the low-pressure drilling fluid in the lower chamber of the piston flows into the second chamber 2132 through the sixth opening a6 of the servo valve core push rod 213, and flows into the fourth annular groove c4 through the fifth opening a5 of the servo valve core push rod 213. The low-pressure fluid in the fourth annular groove c4 enters the low-pressure isolation chamber through the fourth communication port b4 of the servo valve sleeve 211. The low-pressure drilling fluid in the low-pressure isolation chamber is discharged into the annulus outside the drill string through the radial opening on the low-pressure isolation sleeve 152 and the outer shell 11.

[0063] As can be seen from the above, there are two complete paths of the drilling fluid in the position feedback hydraulic servo system driven by the drilling fluid, as follows:

[0064] Path one of the high-pressure drilling fluid: first communication port b1, first annular groove c1, first opening a1, third opening a3 and upper isolation chamber 31.

[0065] The cylindrical piston 212 moves downward to extrude the low-pressure drilling fluid in the lower isolation chamber 32, causing the low-pressure drilling fluid to flow, and the flow path is as follows:

[0066] Path one of the low-pressure drilling fluid: sixth opening a6, second chamber 2132, fifth opening a5, fourth annular groove c4, fourth communication port b4 and low-pressure isolation chamber.

[0067] Path two of the high-pressure drilling fluid: third communication port b3, third annular groove c3, fourth opening a4, second chamber 2132, sixth opening a6 to the lower chamber of the piston.

[0068] The cylindrical piston 212 moves upward to extrude the low-pressure drilling fluid in the upper isolation chamber 31, causing the low-pressure drilling fluid to flow,

[0069] Path two of the low-pressure drilling fluid: third opening a3, first chamber 2131, second opening a2, second annular groove c2, second communication port b2 to the low-pressure isolation chamber.

[0070] The working principle of the position feedback hydraulic servo system driven by the drilling fluid in the present application is described as follows:

[0071] The initial state of the servo piston mechanism is in the balanced position. When the transmission screw in the inner push rotary steering drilling tool drives the transmission block to move downward, the transmission block drives the servo valve sleeve fixedly connected thereto to also move downward, the servo valve sleeve moves downward relative to the servo valve core push rod, the first communication port b1 of the servo valve sleeve communicates with the first annular groove c1 of the servo valve core push rod, the fourth communication port b4 of the servo valve sleeve communicates with the fourth annular groove c4 of the servo valve core push rod, the first chamber communicates with high pressure, the second chamber communicates with low pressure, the upper isolation chamber is a high pressure chamber, the lower isolation chamber is a low pressure chamber, and the piston (cylindrical piston 212) also moves downward under the action of the pressure difference force, stops moving until the servo piston mechanism is in the balanced position again, at which time the piston drives the servo valve core push rod to displace by an equal amount as the servo valve sleeve.

[0072] The initial state of the servo piston mechanism is in the balanced position. When the transmission screw in the inner push rotary steering drilling tool drives the transmission block to move downward, the transmission block drives the servo valve sleeve fixedly connected thereto to also move downward, the servo valve sleeve moves downward relative to the servo valve core push rod, the first communication port b1 of the servo valve sleeve communicates with the first annular groove c1 of the servo valve core push rod, the fourth communication port b4 of the servo valve sleeve communicates with the fourth annular groove c4 of the servo valve core push rod, the first chamber communicates with high pressure, the second chamber communicates with low pressure, the upper isolation chamber is a high pressure chamber, the lower isolation chamber is a low pressure chamber, and the piston (cylindrical piston 212) also moves downward under the action of the pressure difference force, stops moving until the servo piston mechanism is in the balanced position again, at which time the piston drives the servo valve core push rod to displace by an equal amount as the servo valve sleeve.

[0073] It should be noted that the movement of the servo valve sleeve 211 is controlled by the sliding block driven by the adjusting motor, the cylindrical piston 212 and the servo valve core push rod 213 maintain dynamic stability of the relative position under the action of the pressure difference of the drilling fluid inside and outside the drill string, realize the position feedback servo control function, and accurately transmit the movement parameters while providing greater steering force for the inner push rotary steering drilling tool.

[0074] Specifically, as shown in Figures 1 to 4 , Figures 6 to 9 In one embodiment, an annular step is arranged on the servo valve core push rod 213, and the outer periphery of the annular step is sleeved with the cylindrical piston 212.

[0075] Specifically, as shown in Figure 4 In one embodiment, the annular step 214 is arranged eccentrically with the servo valve core push rod 213.

[0076] Specifically, as shown in Figures 11 to 15As shown, in one embodiment, the first flow channel 121 and a plurality of first sub-flow channels 122 connected with the first flow channel 121 are arranged in the flow collection disc 12, a plurality of second sub-flow channels 131 connected with the plurality of first sub-flow channels 122 one by one are arranged in the flow separation cylinder 13, the second flow channel 141 and a plurality of third sub-flow channels 142 connected with the second flow channel 141 are arranged in the flow separation disc 14, the plurality of third sub-flow channels 142 are connected with the plurality of second sub-flow channels 131 one by one, and the first flow channel 121, the plurality of first sub-flow channels 122, the plurality of second sub-flow channels 131, the plurality of third sub-flow channels 142 and the second flow channel 141 form the high-pressure flow channel 40.

[0077] Specifically, as shown in the drawings, Figures 11 to 15 As shown, in one embodiment, a plurality of first radial communication channels 123 are further arranged in the flow collection disc 12, one end of the plurality of first radial communication channels 123 is connected with the first flow channel 121, and the other end is connected with the plurality of first sub-flow channels 122 one by one, and a plurality of second radial communication channels 143 are further arranged in the flow separation disc 14, one end of the plurality of second radial communication channels 143 is connected with the second flow channel 141, and the other end is connected with the plurality of third sub-flow channels 142 one by one.

[0078] In the above arrangement, the plurality of first sub-flow channels 122, the plurality of second sub-flow channels 131, the third sub-flow channels 142, the plurality of first radial communication channels 123 and the plurality of second radial communication channels 143 are arranged around the central axis of the flow distribution mechanism 10. In this way, it is not necessary to pass through the central through hole arranged in the flow separation disc 14, the flow collection disc 12 and the flow separation cylinder 13 to transport the high-pressure drilling fluid to the next part. Thus, more space is provided for the arrangement of the piston cavity, and in turn, a plurality of cylindrical piston cavities 30 can be arranged to arrange a plurality of cylindrical pistons 212. In this way, the cylindrical piston 212 with a circular cross section is easy to process and has good sealing effect, thereby reducing the risk of internal leakage of the servo piston mechanism 20. In turn, the energy conversion efficiency of the high-pressure drilling fluid is improved to ensure that the position feedback hydraulic servo system driven by the drilling fluid can work efficiently and stably.

[0079] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the application, and equivalent components can be substituted therefor. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A drilling fluid driven position feedback hydraulic servo system, characterized by, The drilling fluid driven position feedback hydraulic servo system is used for an inner push type rotary steerable drilling tool, and comprises: a flow distribution mechanism (10) arranged in a wellbore and having a plurality of cylindrical piston cavities (30) arranged at intervals therein, the flow distribution mechanism (10) being in communication with a central high-pressure passage at an upper portion and an annular low-pressure passage at an outer portion at the same time; and a servo piston mechanism (20) comprising a plurality of piston rod assemblies (21), one end of each of the piston rod assemblies (21) being connected to a plurality of transmission blocks of the inner push type rotary steerable drilling tool in a one-to-one correspondence, and the other end of each of the piston rod assemblies (21) being connected to a plurality of adjusting wedge blocks of the inner push type rotary steerable drilling tool in a one-to-one correspondence; wherein the piston rod assembly (21) comprises a cylindrical piston (212), a plurality of the cylindrical pistons (212) being arranged in the plurality of cylindrical piston cavities (30) in a one-to-one correspondence, and sliding of the plurality of transmission blocks being capable of adjusting a conduction mode of the high-pressure passage and the low-pressure passage with the plurality of cylindrical piston cavities (30) to control the servo piston mechanism (20) to act, so as to adjust a spatial position of a surrounding structure center defined by the plurality of adjusting wedge blocks. The flow distribution mechanism (10) comprises: an outer housing (11) arranged in the wellbore; and a flow collecting disc (12) arranged at a bottom portion of the outer housing (11); and a flow distribution cylinder sleeve (13) arranged on the flow collecting disc (12); and a separation disc (14) arranged on the flow distribution cylinder sleeve (13); and an isolation sleeve assembly (15) arranged on the separation disc (14); wherein a plurality of piston rod assemblies (21) are sequentially arranged on the isolation sleeve assembly (15), the separation disc (14), the flow distribution cylinder sleeve (13) and the flow collecting disc (12), the flow distribution cylinder sleeve (13), the separation disc (14) and the flow collecting disc (12) defining a plurality of cylindrical piston cavities (30) arranged at intervals along a circumferential direction of the flow distribution mechanism (10) and a high-pressure flow channel (40), the isolation sleeve assembly (15) having a high-pressure chamber (1511) and a low-pressure chamber (1512) not in communication with the high-pressure chamber (1511), the high-pressure chamber (1511) being in communication with the high-pressure passage, the high-pressure flow channel (40) and the plurality of cylindrical piston cavities (30) at the same time, the low-pressure chamber (1512) being in communication with the low-pressure passage and the plurality of cylindrical piston cavities (30) at the same time, and the cylindrical piston cavities (30) being located at two sides of the corresponding cylindrical pistons (212) in communication with the high-pressure chamber (1511) and the low-pressure chamber (1512) respectively.

2. The drilling fluid driven position feedback hydraulic servo system of claim 1, wherein, The isolation sleeve assembly (15) comprises: a low-pressure isolation sleeve (152) arranged on the separation disc (14); a high-pressure isolation sleeve (151) provided with the high-pressure chamber (1511), the high-pressure isolation sleeve (151) being arranged on the low-pressure isolation sleeve (152); wherein the low-pressure isolation sleeve (152) and the high-pressure isolation sleeve (151) define the low-pressure chamber (1512).

3. The drilling fluid driven position feedback hydraulic servo system of claim 1 wherein, The cylindrical piston (212) separates the cylindrical piston cavity (30) into an upper isolation cavity (31) and a lower isolation cavity (32), and the piston rod assembly (21) further comprises: a servo valve sleeve (211) penetrating the isolation sleeve assembly (15) and provided with an overflow port (2111) at one end, the servo valve sleeve (211) being connected with the transmission block; and a servo valve spool rod (213) penetrating the manifold disc (12), the distribution sleeve (13) and the separation disc (14), one end of the servo valve spool rod (213) extending into the servo valve sleeve (211) from the other end of the servo valve sleeve (211) and being slidingly arranged in the servo valve sleeve (211), the other end of the servo valve spool rod (213) penetrating the manifold disc (12) and being connected with the adjusting wedge block, and the cylindrical piston (212) being sleeved on the outer periphery of the servo valve spool rod (213); wherein the servo valve spool rod (213) is provided with a first chamber (2131) and a second chamber (2132), the relative sliding position of the servo valve sleeve (211) and the servo valve spool rod (213) being adjusted, the first chamber (2131) being capable of conducting the high-pressure chamber (1511) and the upper isolation cavity (31), the second chamber (2132) being capable of conducting the low-pressure chamber (1512) and the lower isolation cavity (32), or the first chamber (2131) being capable of conducting the low-pressure chamber (1512) and the upper isolation cavity (31), and the second chamber (2132) being capable of conducting the high-pressure chamber (1511) and the lower isolation cavity (32).

4. The drilling fluid driven position feedback hydraulic servo system of claim 3, wherein, An annular step is arranged on the servo valve spool rod (213), and the outer periphery of the annular step is sleeved with the cylindrical piston (212).

5. The drilling fluid driven position feedback hydraulic servo system of claim 3 wherein, Six openings are arranged in sequence and at intervals on the outer periphery of the servo valve spool rod (213) in the first direction, wherein the first opening (a1), the second opening (a2) and the third opening (a3) are in communication with the first chamber (2131), the fourth opening (a4), the fifth opening (a5) and the sixth opening (a6) are in communication with the second chamber (2132), the fourth opening (a4), the first opening (a1), the second opening (a2), the fifth opening (a5), the third opening (a3) and the sixth opening (a6) are sequentially and interval arranged in the first direction, and the third opening (a3) and the sixth opening (a6) are arranged on the two sides of the cylindrical piston (212) respectively; four communication ports are arranged at intervals on the outer periphery of the servo valve sleeve (211) in the first direction, wherein the third communication port (b3), the first communication port (b1), the second communication port (b2) and the fourth communication port (b4) are sequentially and interval arranged in the first direction; when the first opening (a1) is in communication with the first communication port (b1), the fifth opening (a5) is in communication with the fourth communication port (b4), when the fourth opening (a4) is in communication with the third communication port (b3), the second opening (a2) is in communication with the second communication port (b2).

6. The drilling fluid driven position feedback hydraulic servo system of claim 5, wherein, The outer periphery of the servo valve spool push rod (213) is provided with four annular grooves, the first opening (a1), the second opening (a2), the fourth opening (a4) and the fifth opening (a5) are provided in the first annular groove (c1) to the fourth annular groove (c4) one by one, when the lower side of the first opening (a1) is aligned with the upper side of the first annular groove (c1), the upper side of the second opening (a2) is aligned with the lower side of the second annular groove (c2), the upper side of the fourth opening (a4) is aligned with the lower side of the third annular groove (c3), and the lower side of the fifth opening (a5) is aligned with the upper side of the fourth annular groove (c4).

7. The drilling fluid driven position feedback hydraulic servo system of claim 4 wherein, The annular step is eccentrically arranged with the servo valve spool push rod (213).

8. The drilling fluid driven position feedback hydraulic servo system of claim 1, wherein, The current collecting disc (12) is provided with a first current collecting flow channel (121) and a plurality of first branch flow channels (122) connected with the first current collecting flow channel (121), the branch cylinder sleeve (13) is provided with a plurality of second branch flow channels (131) connected with the plurality of first branch flow channels (122) one by one, the separation disc (14) is provided with a second current collecting flow channel (141) and a plurality of third branch flow channels (142) connected with the second current collecting flow channel (141), the plurality of third branch flow channels (142) are connected with the plurality of second branch flow channels (131) one by one, and the first current collecting flow channel (121), the plurality of first branch flow channels (122), the plurality of second branch flow channels (131), the plurality of third branch flow channels (142) and the second current collecting flow channel (141) constitute the high-pressure flow channel (40).

9. The drilling fluid driven position feedback hydraulic servo system of claim 8, wherein, The current collecting disc (12) is further provided with a plurality of first radial communication channels (123), one end of the plurality of first radial communication channels (123) is communicated with the first current collecting flow channel (121), and the other end is communicated with the plurality of first branch flow channels (122) one by one, and / or the separation disc (14) is further provided with a plurality of second radial communication channels (143), one end of the plurality of second radial communication channels (143) is communicated with the second current collecting flow channel (141), and the other end is communicated with the plurality of third branch flow channels (142) one by one.

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