Four-wing threshold valve control hydraulic system for vertical drilling tool

Abstract

The invention relates to a four-wing threshold valve control hydraulic system for a vertical drilling tool, which comprises a high-pressure oil way and a low-pressure oil way which are arranged in the vertical drilling tool, a first control system, at least one two-position three-way electromagnetic valve, and a hydraulic cylinder and a piston assembly which are arranged corresponding to the two-position three-way electromagnetic valve, wherein each two-position three-way electromagnetic valve comprises a first passage, a second passage and a third passage, the first passage is communicated with the high-pressure oil way, and the second passage is communicated with the low-pressure oil way; the hydraulic cylinders and the piston assemblies are communicated with third passages of the corresponding two-position three-way electromagnetic valves; and the first control system is configured to switch the communication between the hydraulic cylinder and the piston assembly and the high-pressure oil way or the low-pressure oil way by controlling the conduction of the first passage, the second passage and / or the third passage according to the well deviation condition of the vertical drilling tool so as to execute corresponding deviation correction operation. According to the system, space is saved, and deviation correction and anti-friction acceleration can be reasonably considered to the maximum extent.

Description

Technical Field

[0001] The invention relates to the technical field of vertical drilling, and in particular to a four-wing threshold valve-controlled hydraulic system for a vertical drilling tool. Background Art

[0002] With the increasing demand for drilling deep and ultra-deep wells, vertical drilling tools have become the best solution to ensure the quality of the wellbore. At present, there is a lack of mature domestically produced small-sized vertical drilling tools for the lower well section. The main problems faced by this tool are how to design an efficient hydraulic execution system under limited size and space and how to solve the adaptability problem of the soft mudstone or salt-gypsum layer in the lower well section that is easy to shrink.

[0003] Based on this, the existing technology still needs to be improved. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention designs a modular hydraulic system that is different from the most popular multi-pump and multi-motor system on the market, and redesigns an integrated hydraulic system with a single pump, a single motor, and four-wing rib valve control. The system has the advantages of saving space, large synthetic thrust, and high deflection correction efficiency. In addition, in order to improve the adaptability of tools in soft mudstone or salt-gypsum formations, and take into account the problems of deflection correction and anti-friction and speed-up, the downhole closed loop automatically adjusts the thrust size according to the well inclination. When the well inclination is large, deflection correction is the main focus, and a large deflection correction force is fully pushed out; when the well inclination is small, anti-friction is the main focus, and a small deflection correction force can maintain the body anti-rotation, thereby minimizing the friction resistance of the tool. In other words, the present invention is to solve the problem of small design space and efficient deflection correction of the hydraulic system of miniaturized instruments, and adopts a single pump, a single motor, and a four-wing valve-controlled hydraulic system design, which saves space, has a large synthetic thrust of 90°, and has a good deflection correction effect. Second, in order to take into account deflection correction and anti-friction, a threshold control strategy is adopted, which can not only reduce the energy consumption of the hydraulic system, but also increase the life of the tool.

[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 arranged in the vertical drilling tool, a first control system, at least one two-position three-way solenoid valve, and a cylinder and piston assembly arranged corresponding to the two-position three-way solenoid valve, wherein: each of the two-position three-way solenoid valves comprises 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 corresponding correction operations.

[0006] In an embodiment of the present invention, the first control system is configured to: determine whether to turn on the deflection correction threshold function; in response to turning on the deflection correction threshold function, determine whether the well inclination is less than the stop threshold; and perform corresponding deflection correction operations based on the judgment result of whether the well inclination 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 as follows: after executing the low-pressure push-out correction operation, further determine whether the well inclination is greater than a starting threshold; in response to the well inclination being greater than or equal to the starting threshold, execute the high-thrust push-out correction operation; and in response to the well inclination being less than the starting threshold, continue to execute the low-pressure push-out correction operation.

[0009] In an embodiment of the present invention, the first control system is configured as follows: in response to starting the deflection correction threshold function, before judging whether the well inclination is less than the stop threshold, judging whether to set a stop high-thrust deflection correction flag; in response to not setting the stop high-thrust deflection correction flag, continuing to judge whether the well inclination is less than the stop threshold; and in response to the well inclination being less than the stop threshold, setting the stop high-thrust deflection correction flag and performing a low-pressure push-out deflection correction operation.

[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 deflection correction flag; and clear the stop high-thrust deflection 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: execute a high-thrust push-out deflection correction operation in response to the deflection correction 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 bag assembly and a high-pressure relief valve arranged in the high-pressure oil circuit, wherein the pressure bag assembly and the high-pressure relief valve are respectively connected to the oil pump, the high-pressure relief valve is configured to maintain the guide pressure in the high-pressure oil circuit stable, the pressure bag assembly is configured to store and release energy, and the oil pump is connected to the first passage; a low-pressure relief valve arranged in the low-pressure oil circuit, the low-pressure relief valve is connected to the second passage; and an oil bag assembly arranged between the oil pump and the low-pressure relief valve.

[0013] In an embodiment of the present invention, 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 inclination, 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 by closing the two-position three-way solenoid valve, the corresponding hydraulic cylinder and piston assembly are connected to the low-pressure oil circuit to perform a low-pressure push-out correction operation.

[0014] In an embodiment of the present invention, the cylinder and piston assembly is configured to push out the piston and the pushing wings connected to the piston with a first thrust when connected to the high-pressure oil circuit, so as to perform the high-thrust pushing and correcting operation; and the cylinder and piston assembly is configured to push out the piston and the pushing wings connected to the piston with a second thrust when connected to the low-pressure oil circuit, so as to perform the low-pressure pushing and correcting operation, wherein the first thrust is greater than the second thrust.

[0015] In an embodiment of the present invention, the four-wing threshold valve-controlled hydraulic system for a vertical drilling tool further comprises 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 cylinder and piston assembly are four, and the four cylinder 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 a vertical drilling tool 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 bag assembly and the low-pressure relief valve, the low-pressure pressure sensor being configured to measure the internal pressure of the oil bag assembly; and a throttle valve connected to the oil bag assembly.

[0018] In an embodiment of the present invention, the vertical drilling tool includes a tool body and a pressure compensation assembly arranged in the tool body, the closed outer cavity formed by the pressure compensation assembly and the tool body is connected to the wellbore drilling fluid, and the closed inner cavity formed by the pressure compensation assembly and the drive shaft of the vertical drilling tool is connected to the oil bag in the oil bag assembly and the outside of the pressure bag.

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

[0020] In an embodiment of the present invention, the oil bag assembly, the pressure bag 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 arranged in the vertical drilling tool, which is communicatively connected to the first control system and is 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] On the one hand, the present invention can solve the problem of small design space and difficulty in efficient deflection correction of miniaturized instrument hydraulic systems. It adopts a single-pump, single-motor, four-wing valve-controlled hydraulic system design, which saves space, has a large 90° synthetic thrust and a good deflection correction effect. On the other hand, in order to take into account both deflection correction and anti-friction resistance, a threshold control strategy is adopted, which can reduce the energy consumption of the hydraulic system and increase the tool life. BRIEF DESCRIPTION OF THE DRAWINGS

[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 flow chart according to an embodiment of the present invention is shown;

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

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

[0027] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present invention, it is easy for those skilled in the art to appreciate that multiple modifications are feasible without actually departing from the teaching of the subject matter of the present invention. Accordingly, all such modifications should be included within the scope of the present invention. Without departing from the gist of the present invention, other replacements, modifications, changes and deletions may be made to the design, operating conditions and parameters of the following exemplary embodiments.

[0028] According to the present invention, a four-wing threshold valve controlled hydraulic system 100 for a vertical drilling tool is provided. Figure 1As shown, it includes: a high-pressure oil circuit 110 and a low-pressure oil circuit 120 arranged in a vertical drilling tool, a first control system (not shown in the figure), at least one two-position three-way solenoid valve (for example, two-position three-way solenoid valves 12-15) and a cylinder and piston assembly (for example, cylinder and piston assembly 16-18) arranged 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 110, and the second passage is connected to the low-pressure oil circuit 120; 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 corresponding deflection correction operations. Under the conception of the present invention, when the first passage and the third passage are connected, the cylinder and the piston assembly are connected to the high-pressure oil circuit 110, and a high-thrust push-out correction operation can be performed at this time; when the second passage and the third passage are connected, the cylinder and the piston assembly are connected to the low-pressure oil circuit 120, and a low-pressure push-out correction operation can be performed at this time. The present invention performs different correction operations according to different well inclination conditions, and can reasonably balance correction and friction prevention and speed increase to the greatest extent, as described in other parts of the present 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 bag assembly 1, a filter (e.g., filter 2, filters 8-11), a micro oil pump 3 driven by a motor, a pressure bag assembly 4, a high-pressure relief valve 5, a low-pressure relief valve 6, a pressure sensor (e.g., a high-pressure pressure sensor 7 and a low-pressure pressure sensor 25), a two-position three-way solenoid valve 12-15, a cylinder and piston assembly 16-19, a return spring 20-23, a throttle valve 24, a tool body 26, a drive shaft 27, a pressure compensation assembly 28, a fluid hole 29 and other components. These components can be arranged inside the vertical drilling tool, and some components can also be arranged outside the vertical drilling tool as needed. Figure 1 In the embodiment of the present invention, the number of the two-position three-way solenoid valves and the corresponding cylinder and piston assemblies is four. The four cylinder and piston assemblies can be evenly distributed in the vertical drilling tool, for example, they can be evenly distributed in the radial direction of the same cross section of the vertical drilling tool. Correspondingly, the four cylinder and piston assemblies corresponding to the four cylinder and piston assemblies can also be evenly distributed in the radial direction of the same cross section of the vertical drilling tool, such as Figure 4 As shown, the cylinder and piston assemblies indicated by numbers 1, 2, 3, and 4 are evenly distributed in Figure 4In the vertical drilling tool interface shown by a circle, the circle is divided into eight sectors, each sector corresponds to a piston or two adjacent pistons, when a piston or two adjacent pistons (e.g. Figure 4 When the four hydraulic cylinders and piston assemblies (1+2, 2+3, 3+4 or 1+4) are extended, the guiding force during the correction is large and the pushing direction is more accurate. As an alternative, the four hydraulic cylinders and piston assemblies can also be irregularly distributed in the vertical drilling tool. These four hydraulic cylinders and piston assemblies can share an oil pump 3 and a motor that drives the oil pump 3. Compared with the multi-pump and multi-motor design in the prior art, the design of the present invention has high integration and saves costs on the one hand, and is more suitable for small-sized vertical drilling tools on the other hand, which is conducive to mechanical design and implementation in a small space underground. In other embodiments, the number of two-position three-way solenoid valves and the corresponding hydraulic cylinders and piston assemblies can be one or other numbers except four. The periphery of the piston of the hydraulic cylinder and piston assembly can also be provided with a pushing wing, which can extend outward to different degrees under different thrusts, so as to push against the well wall, so as to correct the deflection on the one hand and prevent friction and speed up on the other hand, as described in other parts of the present invention.

[0030] Continue to refer Figure 1In the embodiment shown, in the four-wing threshold valve-controlled hydraulic system 100 for vertical drilling tools described in the present invention, the hydraulic oil inside the oil bag assembly 1 is connected to the inlet of the oil pump 3 through the filter 2, and the oil pump 3 is driven by a DC brushless motor; the outlet of the oil pump 3 is simultaneously connected to the inside of the pressure bag assembly 4, the high-pressure relief valve 5, the high-pressure pressure sensor 7 and the first passage (i.e., the high-pressure inlet or high-pressure passage) of the four two-position three-way solenoid valves 12 to 15. The oil pump 3, the pressure bag assembly 4 and the high-pressure relief valve 5 can be arranged in the high-pressure oil circuit 110. The function of the high-pressure relief valve 5 is to maintain the high-pressure flow channel of the entire system at a set pressure (called the pilot pressure, for example, it can be set to 80 bar, and other numerical pilot pressures can also be set as needed). The pressure sensor 7 is used to monitor the actual pilot pressure, so as to facilitate the storage and ground monitoring of the actual pilot pressure data (data uploading is not mentioned here). The pressure bag assembly 4 can be configured to store and release energy, and the pressure bag assembly 4 can include a cavity located inside it, the cavity is filled with oil and is provided with a piston and a disc spring group connected to the piston. When the vertical drilling tool changes its high side, at least one two-position three-way solenoid valve is opened, and energy can be quickly released through the compressed disc spring group, which is conducive to the rapid extension of the piston in the cylinder and piston assembly to support the well wall; the two-position three-way solenoid valve 12-15 has two working states and three passages, wherein the first passage is connected to the outlet of the oil pump 3, the second passage (i.e., the low-pressure passage) is simultaneously connected to the low-pressure relief valve 6 and the throttle valve 24, and the third passage is connected to the cylinder and piston assembly 16-19, each of which can be provided with a return spring 20-23. When the oil pump 3 stops working, the system pressure in the piston cavity of the cylinder and piston assembly can be relieved through the throttle valve 24. At this time, under the action of the return spring, it is ensured that the piston and the outer push-and-leave wings can be completely retracted, which is conducive to the drilling and drilling construction. The low-pressure relief valve 6 can be arranged in 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 bag assembly 1, and a low-pressure pressure sensor 25 is installed between the oil bag assembly 1 and the low-pressure relief valve 6, and the low-pressure pressure sensor 25 is used to monitor the internal pressure (oil bag pressure) of the oil bag 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, and other values ​​can also be set as needed), and a throttle valve 24 is connected between the system pressure and the oil bag pressure, and the outlet of the throttle valve 24 is connected to the oil bag assembly 1. It is very advantageous to have a high-pressure relief valve 5 and a low-pressure relief valve 6 in the entire oil circuit. This combination application forms a stable guide pressure and system pressure, and according to different formation lithology and other requirements, its pressure setting is adjustable on the ground.

[0031] The following further combines Figure 1The operating state of the four-wing threshold valve-controlled hydraulic system 100 for vertical drilling tools is described. After the vertical drilling tool starts working, the DC brushless motor drives the micro oil pump 3 to work, pumping the hydraulic oil inside the oil bag assembly 1 into the pressure bag assembly 4 connected to the oil pump 3, the high-pressure relief valve 5, the high-pressure pressure sensor 7 and the first passage of the four two-position three-way solenoid valves 12-15, forming a set guide pressure (for example, set to 80 bar), the pressure bag assembly 4 stores energy by compressing the internal disc spring group, the high-pressure relief valve 5 maintains the guide pressure at a stable set pressure (80 bar), and the high-pressure pressure sensor 7 is used to measure the actual guide pressure during actual downhole work, which is convenient for subsequent data storage and real-time upload (here for display).

[0032] When all four two-position three-way solenoid valves 12-15 are closed, the four cylinders and piston assemblies 16-19 are disconnected from the high-pressure oil circuit 110 (pilot 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 continues to pressurize, the high-pressure relief valve 5 overflows to maintain the stability of the high-pressure oil circuit (pilot pressure P1). As the high-pressure relief valve 5 continues to overflow, the low-pressure relief valve 6 begins to overflow, thereby keeping 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 bag inside the oil bag assembly 1, thereby forming a stable circuit.

[0033] When one or two adjacent two-position three-way solenoid valves are opened (for example, two-position three-way solenoid valves 12 and 13 are opened), the cylinder and piston assemblies 16 and 17 are connected to the high-pressure oil circuit 110 (pilot pressure P1), thereby pushing the cylinder and piston assemblies 16 and 17 to overcome the restoring force of their corresponding return springs 20 and 21 and extend them, for example, with a first thrust to push the corresponding push wings to extend outward and push against the well wall, that is, to perform the large thrust push-out correction operation described in the present invention, thereby giving the drill bit a lateral force to return the vertical drilling tool to the vertical direction. The other two cylinders and piston assemblies 18 and 19 are still connected to the low-pressure oil circuit 120 (system pressure P2). Under this pressure, the cylinder and piston assemblies 18 and 19 respectively support the well wall with a second thrust (system pressure P2) that is smaller than the first thrust, for example, to stabilize the posture and resist earthquakes underground.

[0034] When the high side 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 (for example, the second control system) first closes the two-position three-way solenoid valve 12, the cylinder and piston assembly 16 is connected to the low-pressure oil circuit 120 (system pressure P2), and the original high pressure (pilot pressure P1) of the cylinder and piston assembly 16 is overflowed and 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 cylinder and piston assembly 18 is connected to the high-pressure oil circuit 110 (pilot pressure P1). With the continuous pressurization of the oil pump 3 and the rapid release of the stored energy of the pressure bag assembly 4, the cylinder and piston assembly 18 and its peripheral pushing wings extend, thereby pushing against the well wall with a larger thrust (pilot pressure P1), thus completing the change of the high side of the vertical drilling tool and the control of the two-position three-way solenoid valve, and the reciprocating cycle.

[0035] In an embodiment of the present invention, the vertical drilling tool may include a tool body 26 and a pressure compensation assembly 28 disposed in the tool body 26. The pressure compensation assembly 28 may be located between the drive shaft 27 and the tool body 26. The tool body 26 may be a metal shell that can protect the components disposed therein. The pressure compensation assembly 28 may be a rubber membrane that can be connected to the outside of the vertical drilling tool through a fluid hole 29 disposed on the tool body 26. The closed outer cavity formed by the pressure compensation assembly 28 and the tool body 26 is connected to the wellbore drilling fluid, and the closed inner cavity formed by the pressure compensation assembly 28 and the drive shaft 27 of the vertical drilling tool is connected to the oil bag and the outside of the pressure bag in the oil bag assembly 1. Specifically, the closed outer cavity formed by the pressure compensation assembly 28 and the tool body 26 is connected to the wellbore drilling fluid through the fluid hole 29. In addition, the outer periphery of the oil bag assembly 1, the pressure bag assembly 4 and the two-position three-way solenoid valve 12-15 can be connected to the outside of the wellbore through the pressure compensation assembly 28, thereby playing a role in pressure compensation and improving the reliability of the seal.

[0036] The following further combines Figure 1The pressure compensation states of the four-wing threshold valve controlled hydraulic system 100 for a vertical drilling tool are described. After the vertical drilling tool enters the well, the bottom hole pressure P3 is compensated to the hydraulic oil between the vertical drilling tool and its tool body 26 (called tool annulus pressure P4) through the pressure compensation component 28 and its fluid hole 29. At this time, P3=P4. The hydraulic oil in the tool annulus is connected to the outside of the oil bag in the oil bag component 1 on the one hand, and by squeezing the oil bag component 1, the oil bag pressure P5=P4=P3. Since the oil bag component 1 is compensated by the bottom hole pressure, the high pressure (pilot pressure P1) and low pressure (system pressure P2) in the entire hydraulic system are compensated. Therefore, the pressure difference at both ends of the cylinder and the 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 periphery of the pressure bag component 4 and the two-position three-way solenoid valves 12~15, so the pressure difference borne by its sealing component is not affected by the well depth and bottom hole pressure, and is always maintained at high pressure (pilot pressure P1) or low pressure (system pressure P2).

[0037] In an embodiment of the present invention, the four-wing threshold valve-controlled hydraulic system 100 for a vertical drilling tool may also include a second control system (not shown in the figure), the second control system may cooperate with the first control system, the second control system may be configured to set a correction threshold (for example, the stop threshold and the start threshold described in the present invention), and the first control system may be configured as a closed-loop control to achieve the effect of full push and correction of the side under large well inclination with large push and leaning force, and support of the well wall under small well inclination with small push and leaning force. The first control system may be arranged inside the vertical drilling tool, and the second control system may be arranged outside the vertical drilling tool, for example, at a drilling operation site or other remote control location. In one embodiment of the present invention, the second control system may include a host computer, and the first control system may include a slave computer.

[0038] In order to achieve the deflection correction and anti-friction speed-up of the vertical drilling tool through the four-wing threshold valve-controlled hydraulic system 100 for the vertical drilling tool described in the present invention, the present invention can set the deflection correction threshold through the second control system, and the first control system closed-loop control to achieve the effect of performing a large thrust push-out deflection correction operation under a large well inclination and a low-pressure push-out deflection correction operation under a small well inclination. Specifically, the second control system can set a stop threshold and a start threshold and transmit the setting to the first control system, wherein the start threshold is greater than the stop threshold. Setting the deflection correction threshold can reasonably take into account the deflection correction and anti-friction speed-up to the greatest extent, and also reduce the erroneous operation of frequently switching the push force size due to measurement errors or other reasons when approaching the threshold. The first control system can be configured to perform the following method steps after the vertical drilling tool is powered on when the deflection correction threshold function needs to be used:

[0039] The first step is to determine whether to start the skew correction threshold function.

[0040] In the embodiment of the present invention, the downhole software can automatically identify whether the deflection correction threshold function is activated. When it is identified that the deflection correction threshold function is not activated, the high-side piston high-pressure extension, that is, the high-thrust deflection correction operation is always performed. If the deflection correction threshold function is activated, the next step - the well deflection threshold closed-loop control mode is entered.

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

[0042] When the well inclination is determined to be greater than or equal to the stop threshold, the high-side piston is extended at high pressure, that is, a high-thrust push-out correction operation is performed; when it is determined to be less than the stop threshold, a low-pressure push-out correction operation is performed. When it is less than the stop threshold, a low-pressure push-out correction operation can be performed to prevent inclination and reduce friction during drilling, while reducing power consumption and extending tool life.

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

[0044] When the well inclination is judged to be less than the starting threshold, the low-pressure push-out operation of all four pistons is continued, that is, the low-pressure push-out correction operation is performed; when the well inclination is judged to be greater than or equal to the starting threshold, the high-side piston is extended at high pressure, that is, the high-thrust push-out correction operation is performed.

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

[0046] Below is the reference Figure 1 Further reference to the basis Figure 2 An embodiment of the method steps executed by the first control system is described. Since the well deviation is generally greater than 0.1° when entering the well, the stop threshold can be set to 0.1°, and the start threshold can be set to 0.5°. However, it should be understood that the above specific values ​​are only examples, and other stop thresholds and start thresholds can also be set according to actual conditions.

[0047] After the vertical drilling tool is powered on, it is determined whether the deflection correction threshold function is turned on when the deflection correction threshold function is needed. The vertical drilling tool can have two states, such as 0 and 1, where 0 represents the state where the deflection correction threshold function is not used, and 1 represents the state where the deflection correction threshold function is used. The setting of this state can be set on the ground, or transmitted to the well under the ground notification command to change the state. If the deflection correction threshold function is not turned on, a large thrust push-out deflection correction operation is performed. If the deflection correction threshold function is turned on, it is determined whether the well inclination is less than 0.1°. When the well inclination 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 (for example, two-position three-way solenoid valves 12, 13), and the corresponding cylinder and piston assemblies 16, 17 are connected to the high-pressure oil circuit 110 (pilot pressure P1), and a large thrust push-out deflection correction operation is performed to extend and push against the well wall with a large push force to correct the deflection with all strength. In this mode, the well inclination will continue to decrease when the vertical drilling tool works normally. When the well inclination is reduced to less than 0.1°, the low-pressure push-out correction operation is performed instead, that is, a low-pressure small push-back force is output to reduce the friction generated between the vertical drilling tool and the well wall during drilling. At this time, the four two-position three-way solenoid valves 12-15 are all closed, and the corresponding cylinder and piston assemblies 16-19 are all connected to the low-pressure oil circuit 120 (system pressure P2), extending and using a small push-back force to support the well wall. When the formation deflection force is less than the small push-back force, the well inclination will not rise, and the tool will always maintain a small push-back force output. When the formation deflection force exceeds the push-back force, the well inclination will slowly rise. When the well inclination is greater than or equal to 0.5, a large push-out correction operation will be performed, and the vertical drilling tool will be corrected by a large push-back force again. The well inclination also decreases accordingly. When it is reduced to 0.1° again, the low-pressure push-out correction operation is performed again, and a small push-back force is used instead. The above process is repeated until the vertical drilling tool is powered off.

[0048] Below is the reference Figure 1 Further reference to the basis 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 deflection correction threshold function needs to be used, it is first determined whether the deflection correction threshold function is turned on. If it is not turned on, a high-thrust push-out deflection correction operation is performed until the power is off. If the deflection correction threshold control function is turned on, first determine whether the stop high-thrust deflection correction flag is set. If there is no flag (no flag during initial operation), determine whether the initial well inclination is less than the stop threshold (for example, 0.1°). If it is greater than or equal to the stop threshold, a high-thrust push-out deflection correction operation is performed. If the initial well inclination is less than the stop threshold or the high-thrust push-out deflection correction operation makes the well inclination less than the stop threshold, first set the high-thrust push-out deflection correction flag, and then perform the low-pressure push-out deflection correction operation.

[0049] In the case of judging that there is a stop high-thrust deflection correction flag, it is judged whether the well inclination is greater than the start threshold (for example, 0.5°). If it is less than the start threshold, the low-pressure push-out deflection correction operation status is maintained. If it is greater than the start threshold, the stop high-thrust deflection correction flag is cleared first, and then the high-thrust push-out deflection correction operation is performed. Then the cycle starts from the beginning, and it is repeated.

[0050] The present invention can at least solve the problem of small size and space of the hydraulic system of miniaturized instruments. Moreover, the large thrust push-out and deflection correction operation described in the present invention uses two adjacent hydraulic cylinders and piston assemblies with large synthetic thrust, and good well inclination control. In addition, the threshold control is applied in soft mudstone formations or salt-gypsum layers to take into account both deflection correction and speed increase. When the well inclination is small, deflection correction is no longer the main contradiction, and the push force is reduced to reduce the friction during drilling, release the drilling pressure, and increase the mechanical drilling speed. Moreover, when working with a small push force output, it is beneficial to reduce power consumption and extend the tool life.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by equivalents without departing from the spirit and scope of the present invention, it should be included in 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: A high-pressure oil circuit and a low-pressure oil circuit, 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 are arranged in the vertical drilling tool, wherein: Each of the two-position three-way solenoid valves comprises a first passage, a second passage and a third passage, wherein the first passage is communicated with the high-pressure oil circuit, and the second passage is communicated with the low-pressure oil circuit; The 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 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 corresponding deflection correction operations.

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 to enable the skew correction threshold function; In response to starting the deflection correction threshold function, determining whether the well inclination is less than a stop threshold; and The corresponding inclination correction operation is performed according to the judgment result of whether the well inclination is less than the stop threshold.

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: In response to the well deviation being less than the stop threshold, performing a low-pressure push-out deflection correction operation; and In response to the well inclination being greater than or equal to the stop threshold, a high-thrust push-out deflection correction operation is performed.

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 deflection correction operation, further determining whether the well inclination is greater than a start threshold; In response to the well deviation being greater than or equal to the start threshold, performing the high-thrust push-out deflection correction operation; and In response to the well inclination being less than the start threshold, the low-pressure push-out deflection correction operation is continued.

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 starting the deflection correction threshold function, before determining whether the well inclination is less than the stop threshold, determining whether to set a stop high-thrust deflection correction flag; In response to the stop high-thrust deflection correction flag not being set, continuing to determine whether the well inclination is less than a stop threshold; and In response to the well inclination being less than the stop threshold, the stop high-thrust deflection correction flag is set and a low-pressure push-out deflection 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 deflection correction flag, determining whether the well inclination is greater than or equal to a start threshold; and In response to the well inclination being greater than or equal to a start threshold, the flag for stopping high-thrust deflection correction is cleared.

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: In response to the deflection correction threshold function not being turned on, a high-thrust push-out deflection correction operation is performed.

8. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 3, characterized in that: include: an oil pump, a pressure bag assembly and a high-pressure relief valve disposed in the high-pressure oil circuit, wherein the pressure bag assembly and the high-pressure relief valve are respectively communicated with the oil pump, the high-pressure relief valve is configured to maintain a stable pilot pressure in the high-pressure oil circuit, the pressure bag assembly is configured to store and release energy, and the oil pump is communicated with the first passage; a low-pressure relief valve disposed in the low-pressure oil circuit, the low-pressure relief valve being in communication with the second passage; An oil bag assembly is arranged between the oil pump and the low-pressure relief valve.

9. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 8, 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 deviated, the corresponding hydraulic cylinder and piston assembly are connected to the high-pressure oil circuit to perform a high-thrust push-out deflection correction operation; and The low-pressure push-out and deflection correction operation is performed by closing the two-position three-way solenoid valve so that the corresponding hydraulic cylinder and piston assembly are connected to the low-pressure oil circuit.

10. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 9, characterized in that: The cylinder and piston assembly is configured to push out the piston and the pushing wings connected to the piston with a first thrust when connected to the high-pressure oil circuit, so as to perform the high-thrust pushing and correcting operation; and the cylinder and piston assembly is configured to push out the piston and the pushing wings connected to the piston with a second thrust when connected to the low-pressure oil circuit, so as to perform the low-pressure pushing and correcting operation, wherein the first thrust is greater than the second thrust.

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

12. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 9, characterized in that: It further includes a motor for driving the oil pump, and the two-position three-way solenoid valve and the cylinder and piston assembly are each four in number. 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.

13. The four-wing threshold valve controlled hydraulic system for vertical drilling tools according to claim 8, characterized in that: Further including: a high-pressure pressure sensor connected to the oil pump, wherein the high-pressure pressure sensor is configured to measure the actual pilot 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 is connected to the oil bag assembly.

14. The four-wing threshold valve controlled hydraulic system for a vertical drilling tool according to claim 8, characterized in that: The vertical drilling tool includes a tool body and a pressure compensation assembly arranged in the tool body. The closed outer cavity formed by the pressure compensation assembly and the tool body is connected to the wellbore drilling fluid, and the closed inner cavity formed by the pressure compensation assembly and the drive shaft of the vertical drilling tool is connected to the oil bag in the oil bag assembly and the outside of the pressure bag.

15. The four-wing threshold valve controlled hydraulic system for a vertical drilling tool according to claim 14, characterized in that: The closed outer cavity formed by the pressure compensation assembly and the tool body is communicated with the wellbore drilling fluid through a fluid hole arranged on the tool body.

16. The four-wing threshold valve controlled hydraulic system for a vertical drilling tool according to claim 14, characterized in that: The oil bag assembly, the pressure bag 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.

17. The four-wing threshold valve controlled hydraulic system for a vertical drilling tool according to claim 4, characterized in that: It further includes a second control system arranged in the vertical drilling tool, which is communicatively connected to the first control system and is 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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