Position feedback hydraulic servo system driven by drilling fluid

Abstract

The invention relates to a position feedback hydraulic servo system driven by drilling fluid, relates to the technical field of rotary steering drilling equipment, and is used for solving the problems that a piston is difficult to machine and the sealing performance is poor. Comprising a flow distribution mechanism which is arranged in a shaft, a plurality of cylindrical piston cavities are formed in the flow distribution mechanism at intervals, and the flow distribution mechanism communicates with an upper center high-pressure channel and an outer annular low-pressure channel at the same time; the servo piston mechanism comprises a plurality of piston rod assemblies, one ends of the piston rod assemblies are connected with a plurality of transmission blocks of the inward-pushing type rotary steering drilling tool in a one-to-one correspondence mode, and the other ends of the piston rod assemblies are connected with a plurality of adjusting wedge blocks of the inward-pushing type rotary steering drilling tool in a one-to-one correspondence mode. A flow distribution mechanism is arranged to distribute flow of high-pressure drilling fluid in a high-pressure channel in the center of the upper portion of the drill column, the space of the high-pressure drilling fluid is reasonably utilized, and a plurality of cylindrical piston cavities are formed so that a plurality of cylindrical pistons can be correspondingly arranged. The cylindrical piston is convenient to machine and good in sealing effect, and the risk of internal leakage of the servo piston mechanism is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of rotary steering drilling equipment, and in particular to a drilling fluid driven position feedback hydraulic servo system. Background Art

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

[0003] Chinese patent CN113073939A discloses an inner push type rotary directional drilling tool, which includes a shell body, an adjustment mechanism, a hydraulic drive mechanism and a drill seat adjustment mechanism. The drill seat adjustment mechanism includes an adjustment wedge, an adjustment rod, an adjustment ball seat and a drill seat. The adjustment ball seat is sleeved on the upper end of the adjustment rod and is located in the central space of the three adjustment wedges. A rotation fulcrum is set between the adjustment rod and the shell body, and a drill seat is set at the lower part of the adjustment rod. The adjustment mechanism includes 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 control their speed and direction. The transmission block is threadedly connected with the transmission screw to form a screw nut mechanism, and the transmission block is connected to the control valve. Three groups of adjustment mechanisms and hydraulic drive mechanisms are arranged on the inner circumference of the outer shell body. When working, the adjustment mechanism changes the speed of the speed regulating motor and the axial displacement of the steering control transmission block. The transmission block drives the control valve to control the hydraulic drive mechanism of the corresponding group to produce axial displacement. The hydraulic drive mechanism is connected to the corresponding adjustment wedge block through the pull rod, driving the adjustment wedge block to move periodically and regularly, thereby changing the azimuth angle of the drill bit seat relative to the ground and the structural angle relative to the outer shell body, realizing rotary guided drilling.

[0004] However, the hydraulic drive mechanism in the above technical solution is limited by its own structure and must use a fan-shaped piston. However, the fan-shaped cross-section is a non-standard cross-section, and general sealing methods are based on circular cross-sections and are not completely applicable to fans. At the same time, because the fan-shaped shape is relatively complex and it is difficult to ensure processing accuracy, the processing is difficult, and the processing accuracy and shape and position tolerances of the piston and piston cylinder are the main factors affecting the sealing performance. Therefore, the fan-shaped piston has poor sealing performance, which seriously affects the performance of the hydraulic drive mechanism.

[0005] That is to say, the prior art has the problems of difficult piston processing and poor sealing performance. Summary of the invention

[0006] The invention provides a drilling fluid driven position feedback hydraulic servo system, which is used to solve the problems of difficult piston machining and poor sealing performance.

[0007] The present invention provides a drilling fluid driven position feedback hydraulic servo system, an inner push type rotary steerable drilling tool, which comprises: a flow distribution mechanism, which is arranged in a wellbore, and has a plurality of cylindrical piston chambers arranged at intervals therein, the flow distribution mechanism being connected to an upper central high-pressure channel and an external annular low-pressure channel at the same time; and a servo piston mechanism, which comprises a plurality of piston rod assemblies, one end of which is 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 which is connected to a plurality of adjustment wedge blocks of the inner push type rotary steerable drilling tool in a one-to-one correspondence; wherein the piston rod assembly comprises a cylindrical piston, and a plurality of cylindrical pistons are arranged in a one-to-one correspondence in a plurality of cylindrical piston chambers, and sliding a plurality of transmission blocks can adjust the conduction mode between the high-pressure channel and the low-pressure channel and the plurality of cylindrical piston chambers to control the action of the servo piston mechanism, thereby adjusting the spatial position of the enclosure center defined by the plurality of adjustment wedge blocks.

[0008] In one embodiment, the flow distribution mechanism includes: an outer shell, arranged in the wellbore; and a collecting plate, arranged at the bottom of the outer shell; and a diverter cylinder sleeve, arranged on the collecting plate; and a separation plate, arranged on the diverter cylinder sleeve; and an isolation sleeve assembly, arranged on the separation plate; wherein, a plurality of piston rod assemblies are sequentially passed through the isolation sleeve assembly, the separation plate, the diverter cylinder sleeve and the collecting plate, the diverter cylinder sleeve, the separation plate and the collecting plate define a plurality of cylindrical piston cavities arranged at intervals 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 that is not connected to the high-pressure chamber, the high-pressure chamber is simultaneously connected to the high-pressure channel, the high-pressure flow channel and a plurality of cylindrical piston cavities, the low-pressure chamber is simultaneously connected to the low-pressure channel and a plurality of cylindrical piston cavities, and the connection points between the cylindrical piston cavity and the high-pressure chamber and the low-pressure chamber are respectively located on both sides of the corresponding cylindrical piston.

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

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

[0011] A servo valve sleeve is inserted into the isolation sleeve assembly, one end of which is provided with an overflow port, and the servo valve sleeve is connected to the transmission block; and a servo valve core push rod is inserted into the collecting plate, the diverter cylinder sleeve and the separation plate, one end of which extends from the other end of the servo valve sleeve and is slidably arranged in the servo valve sleeve, and the other end of which passes through the collecting plate and is connected to the adjusting wedge block, and a cylindrical piston sleeve is arranged on the outer periphery of the servo valve core push rod; wherein, a first chamber and a second chamber are arranged in the servo valve core push rod, and the relative sliding position of the servo valve sleeve and the servo valve core push rod is adjusted, the first chamber can connect the high-pressure chamber with the upper isolation chamber, and the second chamber can connect the low-pressure chamber with the lower isolation chamber, or the first chamber can connect the low-pressure chamber with the upper isolation chamber, and the second chamber can connect the high-pressure chamber with the lower isolation chamber.

[0012] In one embodiment, an annular step is provided on the servo valve core push rod, and a cylindrical piston is sleeved on the outer circumference of the annular step.

[0013] In one embodiment, six openings are arranged in sequence on the outer circumference of the servo valve core push rod in the first direction, wherein the first opening a1, the second opening a2 and the third opening a3 are communicated with the first chamber, and 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 arranged in sequence along the first direction, and the third opening a3 and the sixth opening a6 are respectively arranged on both sides of the cylindrical piston; four communication ports are arranged in sequence on the outer circumference of the servo valve sleeve 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 arranged in sequence along 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, and 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 at intervals on the outer periphery of the servo valve core push rod, 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 a 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 third opening a3 is aligned with the lower side of the third annular groove c3, and the lower side of the fourth opening a4 is aligned with the upper side of the fourth annular groove c4.

[0015] In one embodiment, the annular step is eccentrically disposed to the servo valve core push rod.

[0016] In one embodiment, a first collecting channel and a plurality of first diverter channels connected to the first collecting channel are provided in the collecting plate, a plurality of second diverter channels connected to the plurality of first diverter channels in one-to-one correspondence are provided in the diverter cylinder sleeve, a second collecting channel and a plurality of third diverter channels connected to the second collecting channel are provided in the separation plate, the plurality of third diverter channels are connected to the plurality of second diverter channels in one-to-one correspondence, and the first collecting channel, the plurality of first diverter channels, the plurality of second diverter channels, the plurality of third diverter channels and the second collecting channel constitute a high-pressure channel.

[0017] In one embodiment, a plurality of first radial connecting channels are further provided in the collecting disk, one end of the plurality of first radial connecting channels is connected to the first collecting channel, and the other end thereof is connected to the plurality of first diversion channels in a one-to-one correspondence, and / or a plurality of second radial connecting channels are further provided in the separation disk, one end of the plurality of second radial connecting channels is connected to the second collecting channel, and the other end thereof is connected to the plurality of third diversion channels in a one-to-one correspondence.

[0018] Compared with the prior art, the advantages of the present invention are that the high-pressure drilling fluid in the central high-pressure channel at the upper part of the drill string is diverted by setting a flow distribution mechanism, and its space is reasonably utilized to arrange multiple cylindrical piston chambers so as to correspond to the setting of multiple cylindrical pistons. The cylindrical piston with a circular cross-section is easy to process and has a good sealing effect, which reduces the risk of internal leakage of the servo piston mechanism, thereby avoiding the problems of difficult processing and poor sealing performance caused by the use of fan-shaped pistons in the prior art. In addition, 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 THE DRAWINGS

[0019] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0020] Figure 1 is a main cross-sectional view of a drilling fluid driven position feedback hydraulic servo system according to an embodiment of the present invention;

[0021] Figure 2 yes Figure 1 A cross-sectional view of the drilling fluid driven position feedback hydraulic servo system at AA;

[0022] Figure 3 yes Figure 1 A cross-sectional view of the drilling fluid driven position feedback hydraulic servo system at BB;

[0023] Figure 4 yes Figure 1 A cross-sectional view of the position feedback hydraulic servo system driven by drilling fluid at CC;

[0024] Figure 5 yes Figure 1 Assembly diagram of the middle and outer shell, collecting plate, flow distribution cylinder sleeve and separation plate;

[0025] Figure 6 yes Figure 1 A schematic diagram of the three-dimensional structure of the piston rod assembly;

[0026] Figure 7 yes Figure 6 Schematic diagram of the three-dimensional structure of the middle servo valve core push rod;

[0027] Figure 8 yes Figure 6 A schematic diagram of the three-dimensional structure of the middle servo valve core push rod from another angle;

[0028] Fig. 9 yes Figure 6 Schematic diagram of the half-section structure of the middle servo valve core push rod;

[0029] Fig.10 yes Figure 6 A schematic diagram of the half-section structure of the middle servo valve sleeve;

[0030] Fig.11 yes Figure 1 Schematic diagram of the three-dimensional structure of the middle separation disc;

[0031] Fig.12 yes Figure 1 A schematic diagram of the three-dimensional structure of the middle separation disc from another angle;

[0032] Fig.13 yes Figure 1 Schematic diagram of the three-dimensional structure of the middle split cylinder sleeve;

[0033] Fig.14 yes Figure 1 Schematic diagram of the three-dimensional structure of the middle collecting plate;

[0034] Fig.15 yes Figure 1 A schematic diagram of the three-dimensional structure of the central current collecting plate from another angle;

[0035] Fig.16 yes Figure 1 A schematic diagram of the three-dimensional structure of the high-voltage isolation sleeve;

[0036] Fig.17 yes Figure 1 Schematic diagram of the three-dimensional structure of the low-pressure isolation sleeve.

[0037] Reference numerals:

[0038] 10. flow distribution mechanism; 11. outer shell; 12. collecting plate; 121. first collecting flow channel; 122. first flow dividing flow channel; 123. first radial communication channel; 13. flow dividing cylinder sleeve; 131. second flow dividing flow channel; 14. separation plate; 141. second collecting flow channel; 142. third flow dividing flow channel; 143. second radial communication channel; 15. isolation sleeve assembly; 151. high pressure isolation sleeve; 1511. high pressure chamber; 15 2. 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 chamber; 31. Upper isolation chamber; 32. Lower isolation chamber; 40. High-pressure flow channel. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with 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 inner push type rotary steerable drilling tool, the upper part of the inner push type rotary steerable drilling tool is connected to the drill string, the lower part is connected to the drill bit, the internal part is passed through high pressure drilling fluid, and the external part is passed through low pressure drilling fluid. The drilling fluid driven position feedback hydraulic servo system is a functional unit of the inner push type rotary steerable drilling tool, and its upper end is connected to multiple transmission blocks of the inner push type rotary steerable drilling tool, and its lower end is connected to multiple adjustment wedges of the inner push type rotary steerable drilling tool. The drilling fluid driven position feedback hydraulic servo system is driven by the transmission block to work to accurately control and adjust the spatial position of the center of the enclosure defined by multiple adjustment wedges, thereby changing the azimuth angle of the drill bit seat relative to the ground and the structural angle relative to the shell body, thereby realizing rotary steerable drilling. The specific structure and connection relationship of other components of the inner push type rotary steerable drilling tool are prior art, and specific reference can be made to Chinese patent CN113073939A, which will not be described in detail here.

[0041] like Figures 1 to 4As shown, the present invention provides a drilling fluid driven position feedback hydraulic servo system, which includes 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 chambers 30 are arranged therein at intervals. The flow distribution mechanism 10 is connected to the central high-pressure channel at the top and the external annular low-pressure channel at the same time; the servo piston mechanism 20 includes a plurality of piston rod assemblies 21, one end of which is connected to a plurality of transmission blocks of the inner push type rotary steering drilling tool in a one-to-one correspondence, and the other end of which is connected to a plurality of adjustment wedges of the inner push type rotary steering drilling tool in a one-to-one correspondence; the piston rod assembly 21 includes a cylindrical piston 212, and a plurality of cylindrical pistons 212 are arranged in a plurality of cylindrical piston chambers 30 in a one-to-one correspondence. Sliding a plurality of transmission blocks can adjust the conduction mode between the high-pressure channel and the low-pressure channel and the plurality of cylindrical piston chambers 30 to control the action of the servo piston mechanism 20, thereby adjusting the spatial position of the center of the enclosure defined by the plurality of adjustment wedges.

[0042] In the above arrangement, the high-pressure drilling fluid in the central high-pressure channel at the upper part of the drill string is diverted by setting a flow distribution mechanism 10, and its space is reasonably utilized to arrange multiple cylindrical piston chambers 30 so as to correspond to the arrangement of multiple cylindrical pistons 212. The use of multiple cylindrical pistons 212 not only satisfies the requirement of a large piston cross-sectional area, but also simplifies the design and processing of the cylindrical piston 212 compared with the fan-shaped piston, improves the precision, and increases the sealing reliability. In this way, the cylindrical piston 212 with a circular cross-section is easy to process and has a good sealing effect, reducing the risk of internal leakage of the servo piston mechanism 20, thereby avoiding the problems of difficult processing and poor sealing performance caused by the use of fan-shaped pistons in the prior art. In addition, 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.

[0043] Specifically, Figure 5 As shown, in one embodiment, the flow distribution mechanism 10 includes an outer shell 11, a collecting plate 12, a flow distribution cylinder sleeve 13, a separation plate 14 and an isolation sleeve assembly 15.

[0044] The outer shell 11 is arranged in the wellbore; the collecting plate 12 is arranged at the bottom of the outer shell 11; the flow dividing cylinder sleeve 13 is arranged on the collecting plate 12, the separation plate 14 is arranged on the flow dividing cylinder sleeve 13, and the isolation sleeve assembly 15 is arranged on the separation plate 14. A plurality of piston rod assemblies 21 are sequentially arranged on the isolation sleeve assembly 15, the separation plate 14, the flow dividing cylinder sleeve 13 and the collecting plate 12. The flow dividing cylinder sleeve 13, the separation plate 14 and the collecting plate 12 define a plurality of cylindrical piston chambers 30 arranged at intervals along the circumference of 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 a plurality of piston rod assemblies 21, and the low-pressure chamber 1521 is connected to the low-pressure channel. The connecting points between the cylindrical piston cavity 30 and the high-pressure chamber 1511 and the low-pressure chamber 1521 are respectively located on both sides of the corresponding cylindrical piston 212 .

[0045] In the above arrangement, the high-pressure chamber 1511 is used to introduce part of the high-pressure drilling fluid in the central high-pressure channel of the upper part of the drill string into the high-pressure flow channel 40, so as to facilitate the high-pressure flow channel 40 to introduce it into the next connecting component. At the same time, the high-pressure chamber 1511 can introduce another part of the high-pressure drilling fluid into the piston rod assembly 21, providing hydraulic power for the piston rod assembly 21, that is, providing hydraulic power for the position feedback hydraulic servo system driven by the drilling fluid. This ensures that the position feedback hydraulic servo system driven by the drilling fluid can work normally to achieve the spatial position adjustment of the center of the enclosure.

[0046] It should be noted that, since the connection points between the cylindrical piston chamber 30 and the high-pressure chamber 1511 and the low-pressure chamber 1521 are respectively located on both sides of the corresponding cylindrical piston 212, the liquid on both sides of the cylindrical piston 212 in the cylindrical piston chamber 30 can flow normally, and the cylindrical piston 212 can expand and contract normally in the cylindrical piston chamber 30, thereby ensuring that the position feedback hydraulic servo system driven by the drilling fluid can work normally.

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

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

[0049] It should be noted that in the present application, the spatial position of the center of the enclosure defined by the three adjustment wedges is adjusted by precise control through hydraulic servo to change the azimuth angle of the drill seat relative to the ground and the structural angle relative to the outer shell body, thereby realizing rotary guided drilling.

[0050] Specifically, Figure 5 , Fig.16 and Fig.17 As shown, 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, Figure 1 and Figure 5 As shown, in one embodiment, the cylindrical piston divides the cylindrical piston chamber 30 into an upper isolation chamber 31 and a lower isolation chamber 32 .

[0052] Specifically, Figures 1 to 4 As shown, 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 inserted into the isolation sleeve assembly 15, and an overflow port 2111 is provided at one end thereof. The servo valve sleeve 211 is connected to the transmission block; the servo valve core push rod 213 is inserted into the collecting plate 12, the flow dividing cylinder sleeve 13 and the separation plate 14, and one end thereof extends into the servo valve sleeve 211 from the other end thereof and is slidably arranged in the servo valve sleeve 211, and the other end thereof extends out from the collecting plate 12 and is connected to the adjusting wedge block, and the cylindrical piston 212 is sleeved on the outer periphery of the servo valve core push rod 213. A first chamber 2131 and a second chamber 2132 are provided in the servo valve core push rod 213. By adjusting the relative sliding position of the servo valve sleeve 211 and the servo valve core push rod 213, the first chamber 2131 can connect the high-pressure chamber 1511 with the upper isolation chamber 31, and the second chamber 2132 can connect the low-pressure chamber 1521 with the lower isolation chamber 32, or the first chamber 2131 can connect the low-pressure chamber 1521 with the upper isolation chamber 31, and the second chamber 2132 can connect the high-pressure chamber 1511 with the lower isolation chamber 32.

[0053] It should be noted that when the first chamber 2131 can connect the high-pressure chamber 1511 with the upper isolation chamber 31 and the second chamber 2132 can connect the low-pressure chamber 1521 with the lower isolation chamber 32, the cylindrical piston 212 slides downward. When the first chamber 2131 connects the low-pressure chamber 1521 with the upper isolation chamber 31 and the second chamber 2132 connects the high-pressure chamber 1511 with the lower isolation chamber 32, the cylindrical piston 212 slides upward. A sealing end cap 2133 is provided at the upper end of the servo valve core push rod 213, and the sealing end cap 2133 is used to seal the openings of the first chamber 2131 and the second chamber 2132.

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

[0055] Specifically, Figures 6 to 10 As shown, in one embodiment, six openings are sequentially arranged on the outer circumference of the servo valve core push rod 213 in the first direction, wherein the first opening a1, the second opening a2 and the third opening a3 are communicated with the first chamber 2131, the fourth opening a4, the fifth opening a5 and the sixth opening a6 are communicated 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 arranged along 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 on the outer circumference 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 arranged along 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, and 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.

[0056] Specifically, Figures 6 to 9 As shown, in one embodiment, four annular grooves are arranged at intervals on the outer periphery of the servo valve core push rod 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 in a 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 third opening a3 is aligned with the lower side of the third annular groove c3, and the lower side of the fourth opening a4 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 to the high and low pressure flow channels (high pressure chamber 1511 and low pressure chamber 1521) of the distribution mechanism 10, and there is no fluid entering or exiting the two sides of the cylindrical piston 212, 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 fluid flows into the high-pressure isolation sleeve 151 through the center pipe of the inner push rotary directional drilling tool, and a high-pressure isolation chamber (high-pressure chamber 1511) is formed between the high-pressure isolation sleeve 151 and the low-pressure isolation sleeve 152. Part of the high-pressure drilling fluid in the high-pressure isolation chamber flows into the central flow channel of the diverter plate from the high-pressure center pipe in the low-pressure isolation sleeve 152, and then flows out through the diverter flow channels (the second diverter flow channel 131 and the third diverter flow channel 142) of the separation plate 14 and the diverter cylinder sleeve 13, enters the diverter flow channel (the first diverter flow channel 122) on the collecting plate 12, merges in the collecting flow channel (the first collecting flow channel 121), and flows into the high-pressure flow channel of the center pipe of the lower tool. In addition, the remaining part of 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 connected to 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 it can 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 connected to 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 central tube of the low-pressure isolation sleeve 152 and its outer side wall 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 connecting port b2 of the servo valve sleeve 211, and the low-pressure drilling fluid in the low-pressure isolation chamber is discharged into the external annulus of the drill string through the radial openings 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 connecting port b4 of the servo valve sleeve 211, and the low-pressure drilling fluid in the low-pressure isolation chamber is discharged into the external annulus of the drill string through the radial openings on the low-pressure isolation sleeve 152 and the outer shell 11.

[0063] From the above, it can be seen that there are two complete drilling fluid paths in the drilling fluid driven position feedback hydraulic servo system, as follows:

[0064] Path 1 of the high-pressure drilling fluid: the first connecting port b1, the first annular groove c1, the first opening a1, the third opening a3 and the upper isolation chamber 31;

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

[0066] Path 1 of the low-pressure drilling fluid: the sixth opening a6, the second chamber 2132, the fifth opening a5, the fourth annular groove c4, the fourth connecting port b4, and the low-pressure isolation chamber.

[0067] Path 2 of the high-pressure drilling fluid: the third connecting port b3, the third annular groove c3, the fourth opening a4, the second chamber 2132, the sixth opening a6 to the piston lower chamber.

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

[0069] Path 2 of the low-pressure drilling fluid: the third opening a3, the first chamber 2131, the second opening a2, the second annular groove c2, the second connecting port b2 to the low-pressure isolation chamber.

[0070] The working principle of the drilling fluid driven position feedback hydraulic servo system in this application is explained below:

[0071] The servo piston mechanism is initially in a balanced position. When the transmission screw in the internal push rotary steerable drilling tool drives the transmission block to move downward, the transmission block drives the servo valve sleeve fixed thereto to move downward as well. The servo valve sleeve moves downward relative to the servo valve core push rod. The first connecting port b1 of the servo valve sleeve is connected to the first annular groove c1 of the servo valve core push rod, and the fourth connecting port b4 of the servo valve sleeve is connected to the fourth annular groove c4 of the servo valve core push rod. The first chamber is connected to high pressure, and the second chamber is connected to low pressure. The upper isolation chamber is a high pressure chamber, and the lower isolation chamber is a low pressure chamber. The piston (cylindrical piston 212) also moves downward under the action of the pressure differential force, and stops when the servo piston mechanism is in a balanced position again. At this time, the piston drives the servo valve core push rod to move to a displacement equal to that of the servo valve sleeve.

[0072] The servo piston mechanism is initially in a balanced position. When the transmission screw drives the transmission block to move upward, the transmission block also drives the servo valve sleeve fixed to it to move upward, and the servo valve sleeve moves upward relative to the servo valve core push rod. The second connecting port b2 of the servo valve sleeve is connected to the second annular groove c2 of the servo valve core push rod, and the third opening b3 of the servo valve sleeve is connected to the third annular groove c3 of the servo valve core push rod. The first chamber is connected to low pressure, and the second chamber is connected to high pressure. The lower isolation chamber is a high-pressure chamber, and the upper isolation chamber is a low-pressure chamber. The piston also moves upward under the action of the pressure difference force, and stops when the servo piston mechanism is in a balanced position again. At this time, the piston drives the servo valve core push rod to move to a displacement equal to that of the servo valve sleeve.

[0073] It should be noted that the movement of the servo valve sleeve 211 is controlled by adjusting the sliding block driven by the motor. The cylindrical piston 212 and the servo valve core push rod 213 maintain dynamic stability in relative position with the servo valve sleeve 211 under the action of the drilling hydraulic differential force inside and outside the drill string, thereby realizing the position feedback servo control function. While accurately transmitting the motion parameters, it can provide greater guiding force for the internal push rotary steerable drilling tool.

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

[0075] Specifically, Figure 4 As shown, in one embodiment, the annular step 214 is eccentrically disposed with respect to the servo valve core push rod 213 .

[0076] Specifically, Figures 11 to 15As shown, in one embodiment, a first collecting channel 121 and a plurality of first diverter channels 122 connected to the first collecting channel 121 are provided in the collecting plate 12, a plurality of second diverter channels 131 connected one-to-one with the plurality of first diverter channels 122 are provided in the diverter cylinder sleeve 13, a second collecting channel 141 and a plurality of third diverter channels 142 connected to the second collecting channel 141 are provided in the separation plate 14, the plurality of third diverter channels 142 are connected one-to-one with the plurality of second diverter channels 131, the first collecting channel 121, the plurality of first diverter channels 122, the plurality of second diverter channels 131, the plurality of third diverter channels 142 and the second collecting channel 141 constitute a high-pressure channel 40.

[0077] Specifically, Figures 11 to 15 As shown, in one embodiment, a plurality of first radial connecting channels 123 are further provided in the collecting plate 12, one end of the plurality of first radial connecting channels 123 is connected to the first collecting channel 121, and the other end thereof is connected to the plurality of first diverter channels 122 in a one-to-one correspondence, and a plurality of second radial connecting channels 143 are further provided in the separation plate 14, one end of the plurality of second radial connecting channels 143 is connected to the second collecting channel 141, and the other end thereof is connected to the plurality of third diverter channels 142 in a one-to-one correspondence.

[0078] In the above arrangement, a plurality of first diverter channels 122, a plurality of second diverter channels 131, a third diverter channel 142, a plurality of first radial connecting channels 123 and a plurality of second radial connecting channels 143 are arranged around the central axis of the distribution mechanism 10. In this way, there is no need to set a central through hole through the separation plate 14, the collecting plate 12 and the diverter cylinder sleeve 13 to transport the high-pressure drilling fluid to the next part. This provides a larger space for the arrangement of the piston chamber, so that a plurality of cylindrical piston chambers 30 can be arranged to set a plurality of cylindrical pistons 212. In this way, the cylindrical piston 212 with a circular cross-section is easy to process and has a good sealing effect, thereby reducing the risk of internal leakage of the servo piston mechanism 20. This improves the energy conversion efficiency of the high-pressure drilling fluid, so as to ensure that the position feedback hydraulic servo system driven by the drilling fluid can work efficiently and stably.

[0079] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention 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 in that: 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) is arranged in the wellbore, wherein a plurality of cylindrical piston chambers (30) are arranged at intervals, and the flow distribution mechanism (10) is simultaneously connected to the upper central high-pressure channel and the external annular low-pressure channel; and A servo piston mechanism (20) comprising a plurality of piston rod assemblies (21), one end of which is connected one-to-one with a plurality of transmission blocks of the inner-push rotary steerable drilling tool, and the other end of which is connected one-to-one with a plurality of adjustment wedge blocks of the inner-push rotary steerable drilling tool; Wherein, the piston rod assembly (21) includes a cylindrical piston (212), and a plurality of the cylindrical pistons (212) are arranged one by one in a plurality of the cylindrical piston chambers (30), and sliding the plurality of the transmission blocks can adjust the conduction mode between the high-pressure channel and the low-pressure channel and the plurality of the cylindrical piston chambers (30) to control the action of the servo piston mechanism (20), thereby adjusting the spatial position of the center of the enclosure defined by the plurality of the adjustment wedge blocks.

2. The drilling fluid driven position feedback hydraulic servo system according to claim 1, characterized in that: The flow distribution mechanism (10) comprises: an outer shell (11), arranged in the wellbore; and A current collecting plate (12) is arranged at the bottom of the outer shell (11); and A flow-dividing cylinder sleeve (13) is arranged on the collecting plate (12); and A separation plate (14) is arranged on the flow-dividing cylinder sleeve (13); and An isolation sleeve assembly (15) is 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 plate (14), the flow dividing cylinder sleeve (13) and the collecting plate (12); the flow dividing cylinder sleeve (13), the separation plate (14) and the collecting plate (12) define a plurality of cylindrical piston chambers (30) arranged at intervals along the circumference of the distribution mechanism (10) and a high-pressure flow channel (40); the isolation sleeve assembly (15) has a high-pressure chamber (1511) and a high-pressure flow channel (40) connected to the high-pressure chamber (1511). The low-pressure chamber (1512) is not connected, the high-pressure chamber (1511) is connected to the high-pressure channel, the high-pressure flow channel (40) and the multiple cylindrical piston chambers (30) at the same time, the low-pressure chamber (1512) is connected to the low-pressure channel and the multiple cylindrical piston chambers (30) at the same time, and the connection points between the cylindrical piston chamber (30) and the high-pressure chamber (1511) and the low-pressure chamber (1512) are respectively located on both sides of the corresponding cylindrical piston (212).

3. The drilling fluid driven position feedback hydraulic servo system according to claim 2, characterized in that: The isolation sleeve assembly (15) comprises: A low-pressure isolation sleeve (152) is arranged on the separation disc (14); A high-pressure isolation sleeve (151) is provided with the 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 the low-pressure chamber (1512).

4. The drilling fluid driven position feedback hydraulic servo system according to claim 2, characterized in that: The cylindrical piston (212) divides the cylindrical piston chamber (30) into an upper isolation chamber (31) and a lower isolation chamber (32), and the piston rod assembly (21) further comprises: A servo valve sleeve (211) is inserted into the isolation sleeve assembly (15), one end of which is provided with an overflow port (2111), and the servo valve sleeve (211) is connected to the transmission block; and A servo valve core push rod (213) is inserted through the collecting plate (12), the flow dividing cylinder sleeve (13) and the separation plate (14), one end of which extends into the other end of the servo valve sleeve (211) and is slidably arranged in the servo valve sleeve (211), and the other end of which extends out from the collecting plate (12) and is connected to the adjusting wedge block, and the cylindrical piston (212) is sleeved on the outer periphery of the servo valve core push rod (213); In which, 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, and the first chamber (2131) can connect the high-pressure chamber (1511) with the upper isolation chamber (31), and the second chamber (2132) can connect the low-pressure chamber (1512) with the lower isolation chamber (32), or the first chamber (2131) can connect the low-pressure chamber (1512) with the upper isolation chamber (31), and the second chamber (2132) can connect the high-pressure chamber (1511) with the lower isolation chamber (32).

5. The drilling fluid driven position feedback hydraulic servo system according to claim 4, characterized in that: The servo valve core push rod (213) is provided with an annular step, and the cylindrical piston (212) is sleeved on the outer circumference of the annular step.

6. The drilling fluid driven position feedback hydraulic servo system according to claim 4, characterized in that: Six openings are arranged in sequence on the outer circumference of the servo valve core push rod (213) in the first direction, wherein the first opening a1, the second opening a2 and the third opening a3 are communicated with the first chamber (2131), and the fourth opening a4, the fifth opening a5 and the sixth opening a6 are communicated 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 arranged in sequence along 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 arranged in sequence on the outer circumference 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 arranged in sequence along 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, and 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.

7. The drilling fluid driven position feedback hydraulic servo system according to claim 6, characterized in that: Four annular grooves are arranged at intervals on the outer periphery of the servo valve core push rod (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 in a 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 third opening a3 is aligned with the lower side of the third annular groove c3, and the lower side of the fourth opening a4 is aligned with the upper side of the fourth annular groove c4.

8. The drilling fluid driven position feedback hydraulic servo system according to claim 5, characterized in that: The annular step (214) and the servo valve core push rod (213) are eccentrically arranged.

9. The drilling fluid driven position feedback hydraulic servo system according to claim 2, characterized in that: The collecting plate (12) is provided with a first collecting channel (121) and a plurality of first diverting channels (122) connected to the first collecting channel (121); the diverting cylinder sleeve (13) is provided with a plurality of second diverting channels (131) connected to the plurality of first diverting channels (122) in a one-to-one correspondence; the separation plate (14) is provided with a second collecting channel (141) and a plurality of third diverting channels (142) connected to the second collecting channel (141); the plurality of third diverting channels (142) are connected to the plurality of second diverting channels (131) in a one-to-one correspondence; the first collecting channel (121), the plurality of first diverting channels (122), the plurality of second diverting channels (131), the plurality of third diverting channels (142) and the second collecting channel (141) constitute the high-pressure channel (40).

10. The drilling fluid driven position feedback hydraulic servo system according to claim 9, characterized in that: The collecting plate (12) is further provided with a plurality of first radial connecting channels (123), one end of each of the plurality of first radial connecting channels (123) is connected to the first collecting channel (121), and the other end thereof is connected to the plurality of first branching channels (122) in a one-to-one correspondence, and / or the separation plate (14) is further provided with a plurality of second radial connecting channels (143), one end of each of the plurality of second radial connecting channels (143) is connected to the second collecting channel (141), and the other end thereof is connected to the plurality of third branching channels (142) in a one-to-one correspondence.

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