A four-wing threshold valve-controlled hydraulic system for a vertical drilling tool

Abstract

This invention relates to a four-wing threshold valve-controlled hydraulic system for vertical drilling tools, comprising: a high-pressure oil circuit and a low-pressure oil circuit disposed within the vertical drilling tool; a first control system; at least one two-position three-way solenoid valve; and a cylinder and piston assembly corresponding to the two-position three-way solenoid valve. Each two-position three-way solenoid valve includes a first passage, a second passage, and a third passage, wherein the first passage is connected to the high-pressure oil circuit, and the second passage is connected to the low-pressure oil circuit; the cylinder and piston assembly is connected to the third passage of the corresponding two-position three-way solenoid valve; and the first control system is configured to switch the connection between the cylinder and piston assembly and the high-pressure or low-pressure oil circuit by controlling the conduction of the first, second, and / or third passages according to the wellbore inclination of the vertical drilling tool, thereby performing a corresponding deviation correction operation. The system of this invention saves space and can maximize the reasonable balance between deviation correction and friction prevention / speed increase.

Description

Technical Field

[0001] This invention relates to the field of vertical drilling technology, and more specifically to a four-wing threshold valve controlled hydraulic system for vertical drilling tools. Background Technology

[0002] With the increasing demand for drilling deep and ultra-deep wells, vertical drilling tools have become the best solution to ensure wellbore quality. Currently, there is a lack of mature domestically produced small-sized vertical drilling tools for use in the lower well sections. The main challenges for these tools are how to design an efficient hydraulic actuator system under space constraints and how to adapt them to easily necked formations such as soft mudstone or salt gypsum layers in the lower well sections.

[0003] Therefore, existing technologies still need improvement. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention designs an integrated hydraulic system with a single pump, single motor, and four-wing valve control, which differs from the most popular modular hydraulic systems on the market. This system offers advantages such as space saving, high combined thrust, and high deviation correction efficiency. Furthermore, to improve tool adaptability in formations such as soft mudstone or salt-gypsum layers, and to address both deviation correction and friction prevention for increased speed, the downhole closed-loop automatic adjustment of thrust is implemented based on the well deviation. When the well deviation is high, deviation correction is prioritized, with a large deviation correction force pushing the tool forward; when the well deviation is low, friction prevention is prioritized, with a small deviation correction force used to maintain the tool's anti-rotation function, minimizing tool friction. In other words, this invention addresses two key issues: First, it solves the problem of limited space and high-efficiency deviation correction in miniaturized instrument hydraulic systems by adopting a single-pump, single-motor, four-wing valve-controlled hydraulic system design, saving space and achieving a large combined thrust at 90° for effective deviation correction. Second, it employs a threshold control strategy to balance deviation correction and friction prevention, reducing hydraulic system energy consumption and extending tool life.

[0005] Specifically, the present invention provides a four-wing threshold valve controlled hydraulic system for a vertical drilling tool, comprising: a high-pressure oil circuit and a low-pressure oil circuit disposed within the vertical drilling tool, a first control system, at least one two-position three-way solenoid valve, and a cylinder and piston assembly corresponding to the two-position three-way solenoid valve, wherein: each two-position three-way solenoid valve includes a first passage, a second passage, and a third passage, wherein the first passage is connected to the high-pressure oil circuit, and the second passage is connected to the low-pressure oil circuit; the cylinder and piston assembly is connected to the third passage of the corresponding two-position three-way solenoid valve; and the first control system is configured to switch the connection between the cylinder and piston assembly and the high-pressure oil circuit or the low-pressure oil circuit by controlling the conduction of the first passage, the second passage, and / or the third passage according to the well inclination of the vertical drilling tool, so as to perform a corresponding inclination correction operation.

[0006] In an embodiment of the present invention, the first control system is configured to: determine whether to enable the deviation correction threshold function; determine whether the well deviation is less than a stop threshold in response to enabling the deviation correction threshold function; and perform a corresponding deviation correction operation based on the determination result of whether the well deviation is less than the stop threshold.

[0007] In an embodiment of the present invention, the first control system is configured to: perform a low-pressure push-out correction operation in response to the well inclination being less than the stop threshold; and perform a high-thrust push-out correction operation in response to the well inclination being greater than or equal to the stop threshold.

[0008] In an embodiment of the present invention, the first control system is configured to: after performing the low-pressure push-out correction operation, further determine whether the well inclination is greater than a start-up threshold; perform the high-thrust push-out correction operation in response to the well inclination being greater than or equal to the start-up threshold; and continue to perform the low-pressure push-out correction operation in response to the well inclination being less than the start-up threshold.

[0009] In an embodiment of the present invention, the first control system is configured to: determine whether to set a stop high-thrust correction flag before determining whether the well inclination is less than a stop threshold in response to enabling the correction threshold function; continue to determine whether the well inclination is less than the stop threshold in response to not setting the stop high-thrust correction flag; and set the stop high-thrust correction flag and perform a low-pressure push-out correction operation in response to the well inclination being less than the stop threshold.

[0010] In an embodiment of the present invention, the first control system is configured to: determine whether the well inclination is greater than or equal to a start threshold in response to the setting of the stop high thrust correction flag; and clear the stop high thrust correction flag in response to the well inclination being greater than or equal to the start threshold.

[0011] In an embodiment of the present invention, the first control system is configured to perform a high-thrust push-out correction operation in response to the skew threshold function not being enabled.

[0012] In an embodiment of the present invention, a four-wing threshold valve controlled hydraulic system for a vertical drilling tool includes: an oil pump, a pressure bladder assembly, and a high-pressure relief valve disposed within the high-pressure oil circuit, wherein the pressure bladder assembly and the high-pressure relief valve are respectively connected to the oil pump, the high-pressure relief valve is configured to maintain a stable guide pressure within the high-pressure oil circuit, the pressure bladder assembly is configured to store and release energy, and the oil pump is connected to the first passage; a low-pressure relief valve disposed within the low-pressure oil circuit, the low-pressure relief valve being connected to the second passage; and an oil bladder assembly disposed between the oil pump and the low-pressure relief valve.

[0013] In an embodiment of the present invention, the first control system is configured to: perform a high-thrust push-out correction operation by opening one or two adjacent two-position three-way solenoid valves on the high side of the vertical drilling tool when the well is deviated, thereby connecting the corresponding hydraulic cylinder and piston assembly to the high-pressure oil circuit; and perform a low-pressure push-out correction operation by closing the two-position three-way solenoid valves, thereby connecting the corresponding hydraulic cylinder and piston assembly to the low-pressure oil circuit.

[0014] In an embodiment of the present invention, the hydraulic cylinder and piston assembly are configured to extend the piston and the pusher blade connected to the piston with a first thrust when connected to the high-pressure oil circuit, so as to perform the high-thrust extension and tilt correction operation; and the hydraulic cylinder and piston assembly are configured to extend the piston and the pusher blade connected to the piston with a second thrust when connected to the low-pressure oil circuit, so as to perform the low-pressure extension and tilt correction operation, wherein the first thrust is greater than the second thrust.

[0015] In an embodiment of the invention, the four-wing threshold valve controlled hydraulic system for vertical drilling tools further includes a return spring disposed at the end of the piston of the cylinder and piston assembly.

[0016] In an embodiment of the present invention, the four-wing threshold valve controlled hydraulic system for a vertical drilling tool further includes a motor for driving the oil pump, and the number of the two-position three-way solenoid valve and the number of the cylinder and piston assembly are four. The four cylinders and piston assemblies are evenly distributed in the radial direction of the vertical drilling tool and share the oil pump and the motor.

[0017] In an embodiment of the present invention, the four-wing threshold valve controlled hydraulic system for vertical drilling tools further includes: a high-pressure pressure sensor connected to the oil pump, the high-pressure pressure sensor being configured to measure the actual guide pressure in the high-pressure oil circuit during actual downhole operation; a low-pressure pressure sensor disposed between the oil bladder assembly and the low-pressure relief valve, the low-pressure pressure sensor being configured to measure the internal pressure of the oil bladder assembly; and a throttle valve connected to the oil bladder assembly.

[0018] In an embodiment of the present invention, the vertical drilling tool includes a tool body and a pressure compensation component disposed within the tool body. The closed outer cavity formed by the pressure compensation component and the tool body is in communication with the drilling fluid in the wellbore, and the closed inner cavity formed by the pressure compensation component and the drive shaft of the vertical drilling tool is in communication with the outside of the oil bladder and pressure bladder in the oil bladder assembly.

[0019] In an embodiment of the present invention, the closed outer cavity formed by the pressure compensation component and the tool body is connected to the wellbore drilling fluid through a fluid passage provided on the tool body.

[0020] In an embodiment of the present invention, the oil bladder assembly, the pressure bladder assembly, and the periphery of the two-position three-way solenoid valve are all connected to the outside of the wellbore through the pressure compensation assembly.

[0021] In an embodiment of the present invention, the four-wing threshold valve controlled hydraulic system for a vertical drilling tool further includes a second control system disposed within the vertical drilling tool. The second control system is communicatively connected to the first control system and configured to set the stop threshold and the start threshold and send the stop threshold and the start threshold to the first control system, wherein the start threshold is greater than the stop threshold.

[0022] This invention addresses the challenges of limited space and difficulty in achieving efficient tilt correction in miniaturized instrument hydraulic systems by employing a single-pump, single-motor, four-wing valve-controlled hydraulic system design. This design saves space and provides a large 90° combined thrust for effective tilt correction. Furthermore, to balance tilt correction and friction prevention, a threshold control strategy is used, which reduces hydraulic system energy consumption and extends tool life. Attached Figure Description

[0023] Figure 1 A schematic diagram of a four-wing threshold valve controlled hydraulic system for a vertical drilling tool according to an embodiment of the present invention is shown;

[0024] Figure 2 A control strategy flowchart according to an embodiment of the present invention is shown;

[0025] Figure 3 A control strategy flowchart according to another embodiment of the present invention is shown; and

[0026] Figure 4 A sector diagram of a cross-section of a vertical drilling tool according to an embodiment of the present invention is shown. Detailed Implementation

[0027] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0028] According to the present invention, a four-wing threshold valve controlled hydraulic system 100 for vertical drilling tools is provided, such as... Figure 1As shown, it includes: a high-pressure oil passage 110 and a low-pressure oil passage 120 disposed within the vertical drilling tool; a first control system (not shown in the figure); at least one two-position three-way solenoid valve (e.g., two-position three-way solenoid valve 12-15); and a hydraulic cylinder and piston assembly (e.g., hydraulic cylinder and piston assembly 16-18) corresponding to the two-position three-way solenoid valve. Each two-position three-way solenoid valve includes a first passage, a second passage, and a third passage. The first passage is connected to the high-pressure oil passage 110, and the second passage is connected to the low-pressure oil passage 120. The hydraulic cylinder and piston assembly is connected to the third passage of the corresponding two-position three-way solenoid valve. The first control system is configured to switch the connection between the hydraulic cylinder and piston assembly and the high-pressure oil passage or the low-pressure oil passage by controlling the conduction of the first passage, the second passage, and / or the third passage according to the well inclination of the vertical drilling tool, so as to perform a corresponding inclination correction operation. Under the concept of this invention, when the first and third passages are connected, the hydraulic cylinder and piston assembly are connected to the high-pressure oil circuit 110, at which time a high-thrust push-out correction operation can be performed; when the second and third passages are connected, the hydraulic cylinder and piston assembly are connected to the low-pressure oil circuit 120, at which time a low-pressure push-out correction operation can be performed. This invention performs different correction operations according to different well deviation conditions, and can reasonably balance correction and friction prevention and speed improvement to the greatest extent, as described in other parts of this invention.

[0029] exist Figure 1 In the illustrated embodiment, the four-wing threshold valve controlled hydraulic system 100 for a vertical drilling tool may include an oil bladder assembly 1, filters (e.g., filters 2, filters 8-11), a motor-driven micro oil pump 3, a pressure bladder assembly 4, a high-pressure relief valve 5, a low-pressure relief valve 6, pressure sensors (e.g., high-pressure pressure sensor 7 and low-pressure pressure sensor 25), two-position three-way solenoid valves 12-15, cylinder and piston assemblies 16-19, return springs 20-23, a throttle valve 24, a tool body 26, a drive shaft 27, a pressure compensation assembly 28, and a fluid passage 29, etc. These components can all be housed inside the vertical drilling tool, or some components can be housed outside the vertical drilling tool as needed. Figure 1 In this embodiment, the number of two-position three-way solenoid valves and their corresponding hydraulic cylinders and piston assemblies is four. These four hydraulic cylinders and piston assemblies can be evenly distributed within the vertical drilling tool, for example, they can be evenly distributed radially along the same cross-section of the vertical drilling tool. Correspondingly, the four hydraulic cylinders and piston assemblies corresponding to these four hydraulic cylinders and piston assemblies can also be evenly distributed radially along the same cross-section of the vertical drilling tool, such as... Figure 4 As shown, the hydraulic cylinders and piston assemblies, labeled 1, 2, 3, and 4 respectively, are evenly distributed in... Figure 4On the interface of a vertical drilling tool, shown in a circle, the circle is divided into eight sectors, each sector corresponding to one piston or two adjacent pistons. When one piston or two adjacent pistons (e.g.) Figure 4 When the 1+2, 2+3, 3+4, or 1+4 components extend, the guiding force during deviation correction is large, and the pushing direction is more precise. Alternatively, the four hydraulic cylinders and piston assemblies can be randomly distributed within the vertical drilling tool. These four hydraulic cylinders and piston assemblies can share a single oil pump 3 and the motor driving the oil pump 3. Compared with the multi-pump, multi-motor design in the prior art, this design of the present invention has high integration and saves costs. On the other hand, it is more suitable for small-sized vertical drilling tools and is beneficial for mechanical design and implementation in confined downhole spaces. In other embodiments, the number of two-position three-way solenoid valves and their corresponding hydraulic cylinders and piston assemblies can be one or other numbers besides four. The piston periphery of the hydraulic cylinder and piston assembly can also be provided with a pusher wing, which can extend outward to different degrees under different thrusts, thereby pushing against the well wall to correct deviation and prevent friction and increase speed, as described in other parts of the present invention.

[0030] Continue to refer to Figure 1In the illustrated embodiment, in the four-wing threshold valve controlled hydraulic system 100 for vertical drilling tools described in this invention, the hydraulic oil inside the bladder assembly 1 is connected to the inlet of the oil pump 3 via a filter 2. The oil pump 3 is driven by a DC brushless motor. The outlet of the oil pump 3 is simultaneously connected to the interior of the pressure bladder assembly 4, the high-pressure relief valve 5, the high-pressure sensor 7, and the first passage (i.e., the high-pressure inlet or high-pressure passage) of four two-position three-way solenoid valves 12-15. The oil pump 3, the pressure bladder assembly 4, and the high-pressure relief valve 5 can be located within the high-pressure oil circuit 110. The function of the high-pressure relief valve 5 is to maintain the high-pressure flow path of the entire system at a set pressure (called the guide pressure, for example, it can be set to 80 bar, or other values ​​of guide pressure can be set as needed). The pressure sensor 7 is used to monitor the actual guide pressure for storage of actual guide pressure data and surface monitoring (data upload is not mentioned here). The pressure bladder assembly 4 can be configured to store and release energy. The pressure bladder assembly 4 may include an internal cavity filled with oil and equipped with a piston and a disc spring assembly connected to the piston. When the vertical drilling tool changes height, at least one two-position three-way solenoid valve opens, allowing energy to be quickly released through the compressed disc spring assembly. This facilitates the rapid extension of the piston in the hydraulic cylinder and piston assembly, supporting the wellbore. The two-position three-way solenoid valves 12-15 have two operating states and three pathways. The first pathway connects to the outlet of the oil pump 3; the second pathway (i.e., the low-pressure pathway) connects to both the low-pressure relief valve 6 and the throttle valve 24; and the third pathway connects to the hydraulic cylinder and piston assembly 16-19. Each of the hydraulic cylinders and piston assemblies 16-19 can be equipped with a return spring 20-23. When the oil pump 3 stops working, the system pressure in the piston cavity of the hydraulic cylinder and piston assembly can be released through the throttle valve 24. At this time, under the action of the return spring, the piston and the outer pusher blades can be completely retracted, which is beneficial for drilling and tripping operations. A low-pressure relief valve 6 can be installed within the low-pressure oil circuit 120. The inlet of the low-pressure relief valve 6 is connected to the second passage, and the outlet of the low-pressure relief valve 6 is connected to the oil bladder assembly 1. A low-pressure pressure sensor 25 is installed between the oil bladder assembly 1 and the low-pressure relief valve 6. The low-pressure pressure sensor 25 is used to monitor the internal pressure (oil bladder pressure) of the oil bladder assembly 1. The pressure between the high-pressure relief valve 5 and the low-pressure relief valve 6 is called the system pressure (for example, it can be set to 20 bar, or other values ​​can be set as needed). A throttle valve 24 is connected between the system pressure and the oil bladder pressure, and the outlet of the throttle valve 24 is connected to the oil bladder assembly 1. It is very advantageous to have both the high-pressure relief valve 5 and the low-pressure relief valve 6 installed in the entire oil circuit. This combination creates stable guide pressure and system pressure, and the pressure setting is adjustable according to different formation lithology and other requirements.

[0031] The following further combines Figure 1This describes the operation of a four-wing threshold valve controlled hydraulic system 100 used in vertical drilling tools. After the vertical drilling tool begins operation, a DC brushless motor drives a micro-pump 3 to pump hydraulic oil from the oil bladder assembly 1 into the pressure bladder assembly 4, high-pressure relief valve 5, high-pressure sensor 7, and the first passage of four two-position three-way solenoid valves 12-15, forming a set guide pressure (e.g., 80 bar). The pressure bladder assembly 4 stores energy by compressing its internal disc spring assembly. The high-pressure relief valve 5 maintains the guide pressure at a stable set pressure (80 bar). The high-pressure sensor 7 measures the actual guide pressure during downhole operation, facilitating subsequent data storage and real-time uploading (displayed here).

[0032] When all four two-position three-way solenoid valves 12-15 are closed, the four hydraulic cylinders and piston assemblies 16-19 are disconnected from the high-pressure oil circuit 110 (guide pressure P1), and the low-pressure oil circuit (system pressure P2) between the high-pressure relief valve 5 and the low-pressure relief valve 6 is always connected. As the oil pump 3 continuously pressurizes, the high-pressure relief valve 5 overflows to maintain the stability of the high-pressure oil circuit (guide pressure P1). As the high-pressure relief valve 5 continues to overflow, the low-pressure relief valve 6 begins to overflow, thereby maintaining the low-pressure oil circuit 120 (system pressure P2) constant. The hydraulic oil overflowing from the low-pressure relief valve 6 returns to the oil bladder inside the oil bladder assembly 1, thus forming a stable circuit.

[0033] When one or two adjacent two-position three-way solenoid valves are opened (e.g., two-position three-way solenoid valves 12 and 13 are opened), the hydraulic cylinders and piston assemblies 16 and 17 are connected to the high-pressure oil circuit 110 (guide pressure P1), thereby pushing the hydraulic cylinders and piston assemblies 16 and 17 to overcome the restoring force of their corresponding return springs 20 and 21 and extend them. For example, a first thrust is used to push the corresponding pusher blades outward to push against the well wall, that is, to perform the high-thrust push-out correction operation described in this invention, thereby giving the drill bit a lateral force so that the vertical drilling tool returns to the vertical direction. The other two hydraulic cylinders and piston assemblies 18 and 19 are still connected to the low-pressure oil circuit 120 (system pressure P2). Under this pressure, the hydraulic cylinders and piston assemblies 18 and 19 support the well wall with a second thrust (system pressure P2) that is less than the first thrust, which plays a role in stabilizing the attitude and resisting downhole vibration.

[0034] When the height of the vertical drilling tool changes, the control of the two-position three-way solenoid valve also changes (for example, the two-position three-way solenoid valves 13 and 14 are opened). At this time, the control system (e.g., the second control system) first closes the two-position three-way solenoid valve 12, and the hydraulic cylinder and piston assembly 16 is connected to the low-pressure oil circuit 120 (system pressure P2). The original high pressure (guide pressure P1) of the hydraulic cylinder and piston assembly 16 is released to the low pressure (system pressure P2) through the low-pressure relief valve 6. The two-position three-way solenoid valve 14 is opened, and the hydraulic cylinder and piston assembly 18 is connected to the high-pressure oil circuit 110 (guide pressure P1). As the oil pump 3 pressurizes and the energy stored in the pressure bladder assembly 4 is released rapidly, the hydraulic cylinder and piston assembly 18 and its surrounding pusher wings extend, thereby pushing against the well wall with a large thrust (guide pressure P1). In this way, the change of the height of the vertical drilling tool and the control of the two-position three-way solenoid valve is completed, and the cycle repeats.

[0035] In embodiments of the present invention, a vertical drilling tool may include a tool body 26 and a pressure compensation component 28 disposed within the tool body 26. The pressure compensation component 28 may be located between the drive shaft 27 and the tool body 26. The tool body 26 may be a metal casing that protects the components disposed therein. The pressure compensation component 28 may be a rubber diaphragm, and may communicate with the outside of the vertical drilling tool through a fluid passage 29 disposed on the tool body 26. The closed outer cavity formed by the pressure compensation component 28 and the tool body 26 is in communication with the drilling fluid in the wellbore, and the closed inner cavity formed by the pressure compensation component 28 and the drive shaft 27 of the vertical drilling tool is in communication with the outside of the oil bladder and pressure bladder in the oil bladder assembly 1. Specifically, the closed outer cavity formed by the pressure compensation component 28 and the tool body 26 is in communication with the drilling fluid in the wellbore through the fluid passage 29. In addition, the periphery of the oil bladder assembly 1, the pressure bladder assembly 4, and the two-position three-way solenoid valves 12-15 may also be in communication with the outside of the wellbore through the pressure compensation component 28, thereby achieving pressure compensation and improving the reliability of the seal.

[0036] The following further combines Figure 1Describes the pressure compensation status of a four-wing threshold valve controlled hydraulic system 100 used for vertical drilling tools. After the vertical drilling tool enters the well, the bottom hole pressure P3 is compensated by the pressure compensation component 28 and its fluid passage 29 to the hydraulic oil between the vertical drilling tool and its tool body 26 (called the tool annulus pressure P4). At this time, P3 = P4. The hydraulic oil in the tool annulus is connected to the outside of the oil bladder in the oil bladder assembly 1. By squeezing the oil bladder assembly 1, the oil bladder pressure P5 = P4 = P3. Since the oil bladder assembly 1 has been compensated by the bottom hole pressure, both the high pressure (guide pressure P1) and the low pressure (system pressure P2) in the entire hydraulic system are compensated. Therefore, the pressure difference between the two ends of the cylinder and piston assembly is not affected by the well depth and is always maintained at P1. On the other hand, the hydraulic oil in the tool annulus is also connected to the pressure bladder assembly 4 and the periphery of the two-position three-way solenoid valves 12-15. Therefore, the pressure difference borne by its sealing assembly is not affected by the well depth and bottom hole pressure and is always maintained at high pressure (guide pressure P1) or low pressure (system pressure P2).

[0037] In embodiments of the present invention, the four-wing threshold valve controlled hydraulic system 100 for vertical drilling tools may further include a second control system (not shown in the figures). The second control system may cooperate with the first control system. The second control system may be configured to set deviation correction thresholds (e.g., the stop threshold and start threshold described in this invention), while the first control system may be configured to perform closed-loop control to achieve the effect of full-force pushing and lifting of the side deviation correction under large well inclination and small pushing and supporting the well wall under small well inclination. The first control system may be located inside the vertical drilling tool, while the second control system may be located outside the vertical drilling tool, for example, at the drilling site or other remote control location. In one embodiment of the present invention, the second control system may include a host computer, while the first control system may include a slave computer.

[0038] To achieve deviation correction and friction-prevention speed increase of vertical drilling tools using the four-wing threshold valve controlled hydraulic system 100 described in this invention, the invention can set a deviation correction threshold through a second control system. The first control system uses closed-loop control to achieve the effect of performing high-thrust deviation correction operation under high well inclination and low-pressure deviation correction operation under low well inclination. Specifically, the second control system can set a stop threshold and a start threshold and transmit these settings to the first control system, where the start threshold is greater than the stop threshold. Setting the deviation correction threshold can maximize the reasonable balance between deviation correction and friction-prevention speed increase, and also reduce erroneous operations caused by frequent switching of thrust magnitude due to measurement errors or other reasons when approaching the threshold. The first control system can be configured to perform the following steps after the vertical drilling tool is powered on, when the deviation correction threshold function is required:

[0039] The first step is to determine whether the tilt correction threshold function should be activated.

[0040] In embodiments of the present invention, the downhole software can automatically identify whether the deviation correction threshold function is activated. When the deviation correction threshold function is not activated, the high-side piston high-pressure extension, i.e., high-thrust push-out deviation correction operation, is always executed. If the deviation correction threshold function is activated, the next step - well deviation threshold closed-loop control mode - is entered.

[0041] The second step is to determine whether the well inclination is less than the stopping threshold.

[0042] When the well deviation is determined to be greater than or equal to the stop threshold, the high-pressure piston extension is executed, i.e., a high-thrust push-out correction operation is performed; when the deviation is determined to be less than the stop threshold, a low-pressure push-out correction operation is performed. When the deviation is less than the stop threshold, a low-pressure push-out correction operation can be performed, which helps to prevent deviation and reduce friction during drilling, while also reducing power consumption and extending tool life.

[0043] The third step is to determine whether the well inclination exceeds the start-up threshold.

[0044] When the well inclination is determined to be less than the start threshold, the operation of all four pistons being pushed out at low pressure continues, i.e., the low-pressure push-out correction operation is performed; when the well inclination is determined to be greater than or equal to the start threshold, the high-pressure extension of the high-side piston is performed, i.e., the high-thrust push-out correction operation is performed.

[0045] Step 4: Repeat steps 2 and 3 until the tool is powered off.

[0046] The following is for reference. Figure 1 Further reference based on the basics Figure 2 This describes one embodiment of the method steps executed by the first control system. Since the well inclination is typically large, exceeding 0.1°, during well entry, the stop threshold can be set to 0.1°, while the start threshold can be 0.5°. However, it should be understood that the specific values ​​described above are merely illustrative, and other stop and start threshold values ​​can be set according to actual conditions.

[0047] After the vertical drilling tool is powered on, it determines whether to activate the deviation correction threshold function when required. The vertical drilling tool can have two states, such as 0 and 1, where 0 represents the state where the deviation correction threshold function is not used and 1 represents the state where the deviation correction threshold function is used. This state setting can be set on the surface or transmitted to the well via a surface notification command to change the state. If the deviation correction threshold function is not activated, a high-thrust push-out deviation correction operation is performed. If the deviation correction threshold function is activated, it is determined whether the well deviation is less than 0.1°. When the well deviation is large and greater than or equal to 0.1°, the first control system can control one or two adjacent two-position three-way solenoid valves in the high-side position to open (e.g., two-position three-way solenoid valves 12 and 13), and the corresponding hydraulic cylinders and piston assemblies 16 and 17 are connected to the high-pressure oil circuit 110 (guide pressure P1), performing a high-thrust push-out deviation correction operation to extend and push against the well wall with a large thrust to fully correct the deviation. In this mode, the well deviation will continuously decrease when the vertical drilling tool is working normally. Once the well inclination drops to less than 0.1°, a low-pressure push-out correction operation is initiated. This involves using a low-pressure, small-push force to reduce friction between the vertical drilling tool and the wellbore during drilling. At this time, all four two-position three-way solenoid valves 12-15 are closed, and the hydraulic cylinders and piston assemblies 16-19 are connected to the low-pressure oil circuit 120 (system pressure P2), extending and supporting the wellbore with a small push force. When the formation build-up force is less than the small push force, the well inclination will not rise, and the tool maintains a small push force output. When the formation build-up force exceeds the push force, the well inclination will slowly rise. When the well inclination reaches 0.5° or greater, a high-push-out correction operation is initiated, and the vertical drilling tool is corrected again with a large push force. The well inclination then decreases. When it drops back to 0.1°, the low-pressure push-out correction operation is repeated, using a small push force. This process is repeated until the vertical drilling tool is de-energized.

[0048] The following is for reference. Figure 1 Further reference based on the basics Figure 3 Another embodiment of the method steps executed by the first control system is described. After the vertical drilling tool is powered on, the well inclination is measured. When the inclination correction threshold function is required, it is first determined whether the inclination correction threshold function is enabled. If it is not enabled, a high-thrust push-out inclination correction operation is performed until power is cut off. If the inclination correction threshold control function is enabled, it is first determined whether a stop high-thrust inclination correction flag is set. If there is no flag (no flag during initial operation), it is determined whether the initial well inclination is less than the stop threshold (e.g., 0.1°). If it is greater than or equal to the stop threshold, a high-thrust push-out inclination correction operation is performed. If the initial well inclination is less than the stop threshold or the high-thrust push-out inclination correction operation causes the well inclination to be less than the stop threshold, the high-thrust push-out inclination correction flag is set first, and then a low-pressure push-out inclination correction operation is performed.

[0049] If a stop high-thrust deviation correction flag is detected, check if the well deviation is greater than the activation threshold (e.g., 0.5°). If it is less than the activation threshold, maintain the current low-pressure push-out deviation correction operation. If it is greater than the activation threshold, first clear the stop high-thrust deviation correction flag, then execute the high-thrust push-out deviation correction operation. Then start the cycle again, repeating this process.

[0050] This invention at least solves the problem of limited space in miniaturized instrument hydraulic systems. Furthermore, the high-thrust push-out correction operation described in this invention utilizes the combined thrust of two adjacent hydraulic cylinders and piston assemblies, resulting in high wellbore inclination control. In addition, threshold control is applicable in soft mudstone or salt-gypsum formations, balancing wellbore correction and speed increase. When wellbore inclination is low, wellbore correction is no longer the primary concern; reducing the push force reduces friction during drilling, releases drilling pressure, and increases mechanical drilling rate. Moreover, operating with low push force helps reduce power consumption and extend tool life.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications or equivalent substitutions made to the present invention without departing from the spirit and scope thereof should be covered within the protection scope of the claims of the present invention.

Claims

1. A four-wing threshold valve controlled hydraulic system for vertical drilling tools, characterized in that, include: The vertical drilling tool is equipped with high-pressure and low-pressure oil circuits, a first control system, a two-position three-way solenoid valve, and a hydraulic cylinder and piston assembly corresponding to the two-position three-way solenoid valve. The number of the two-position three-way solenoid valve and the hydraulic cylinder and piston assembly are both four. Each of the two-position three-way solenoid valves includes a first passage, a second passage, and a third passage, wherein the first passage is connected to the high-pressure oil circuit, and the second passage is connected to the low-pressure oil circuit; The hydraulic cylinder and piston assembly are connected to the third passage of the corresponding two-position three-way solenoid valve; and The first control system is configured to switch the connection between the hydraulic cylinder and piston assembly and the high-pressure oil circuit or the low-pressure oil circuit by controlling the conduction of the first passage and the third passage, or by controlling the conduction of the second passage and the third passage, according to the well inclination of the vertical drilling tool, so as to perform the corresponding inclination correction operation. The four-wing threshold valve controlled hydraulic system for vertical drilling tools further includes: an oil pump, a pressure bladder assembly, and a high-pressure relief valve disposed within the high-pressure oil circuit, wherein the pressure bladder assembly and the high-pressure relief valve are respectively connected to the oil pump, the high-pressure relief valve is configured to maintain a stable guide pressure within the high-pressure oil circuit, the pressure bladder assembly is configured to store and release energy, and the oil pump is connected to the first passage; a low-pressure relief valve disposed within the low-pressure oil circuit, the low-pressure relief valve being connected to the second passage; and an oil bladder assembly disposed between the oil pump and the low-pressure relief valve. The vertical drilling tool includes a tool body and a pressure compensation assembly disposed within the tool body. The closed outer cavity formed by the pressure compensation assembly and the tool body is in communication with the drilling fluid in the wellbore, and the closed inner cavity formed by the pressure compensation assembly and the drive shaft of the vertical drilling tool is in communication with the oil bladder and pressure bladder of the oil bladder assembly.

2. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 1, characterized in that, The first control system is configured as follows: Determine whether the tilt correction threshold function is enabled; In response to enabling the deviation correction threshold function, it is determined whether the well deviation is less than the stop threshold; and Based on the determination result of whether the well inclination is less than the stop threshold, the corresponding inclination correction operation is performed.

3. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 2, characterized in that, The first control system is configured as follows: A low-pressure pull-out correction operation is performed in response to the well deviation being less than the stop threshold; and A high-thrust push-out deviation correction operation is performed in response to the well inclination being greater than or equal to the stop threshold.

4. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 3, characterized in that, The first control system is configured as follows: After performing the low-pressure push-out correction operation, it is further determined whether the well deviation is greater than the activation threshold; The high-thrust push-out correction operation is performed in response to the well inclination being greater than or equal to the initiation threshold; and The low-pressure push-out correction operation continues in response to the well inclination being less than the activation threshold.

5. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 2, characterized in that, The first control system is configured as follows: In response to enabling the deviation correction threshold function, determine whether to set a stop high-thrust deviation correction flag before determining whether the well deviation is less than the stop threshold; In response to the absence of the stop high-thrust correction flag, the system continues to determine whether the well inclination is less than the stop threshold; and In response to the well inclination being less than the stop threshold, the stop high-thrust correction flag is set and a low-pressure push-out correction operation is performed.

6. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 5, characterized in that, The first control system is configured as follows: In response to the setting of the stop high-thrust deviation correction flag, it is determined whether the well deviation is greater than or equal to the start threshold; and The stop high-thrust correction flag is cleared in response to the well inclination being greater than or equal to the start threshold.

7. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 2, characterized in that, The first control system is configured as follows: A high-thrust push-out tilt correction operation is performed in response to the tilt correction threshold function not being enabled.

8. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 1, characterized in that, The first control system is configured as follows: By opening one or two adjacent two-position three-way solenoid valves on the high side of the vertical drilling tool when the well is tilted, the corresponding hydraulic cylinder and piston assembly are connected to the high-pressure oil circuit to perform a high-thrust push-out correction operation; and The low-pressure push-out correction operation is performed by closing the two-position three-way solenoid valve to connect the corresponding hydraulic cylinder and piston assembly to the low-pressure oil circuit.

9. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 8, characterized in that, The hydraulic cylinder and piston assembly are configured to extend the piston and the pusher blade connected to the piston with a first thrust when connected to the high-pressure oil circuit, so as to perform the high-thrust extension and tilt correction operation; and the hydraulic cylinder and piston assembly are configured to extend the piston and the pusher blade connected to the piston with a second thrust when connected to the low-pressure oil circuit, so as to perform the low-pressure extension and tilt correction operation, wherein the first thrust is greater than the second thrust.

10. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 9, characterized in that, It further includes a return spring disposed at the end of the piston of the cylinder and piston assembly.

11. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 8, characterized in that, The tool further includes a motor that drives the oil pump, and four hydraulic cylinders and piston assemblies are evenly distributed radially on the vertical drilling tool and share the oil pump and the motor.

12. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 1, characterized in that, Further includes: A high-pressure sensor connected to the oil pump is configured to measure the actual guiding pressure in the high-pressure oil circuit during actual downhole operation. A low-pressure sensor is disposed between the oil bladder assembly and the low-pressure relief valve, the low-pressure sensor being configured to measure the internal pressure of the oil bladder assembly; and A throttle valve connected to the oil bladder assembly.

13. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 1, characterized in that, The closed outer cavity formed by the pressure compensation component and the tool body is connected to the wellbore drilling fluid through a fluid passage hole provided on the tool body.

14. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 1, characterized in that, The oil bladder assembly, the pressure bladder assembly, and the two-position three-way solenoid valve are all connected to the outside of the wellbore through the pressure compensation assembly.

15. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 4, characterized in that, The system further includes a second control system disposed within the vertical drilling tool. The second control system is communicatively connected to the first control system and configured to set the stop threshold and the start threshold and send the stop threshold and the start threshold to the first control system, wherein the start threshold is greater than the stop threshold.

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