A sub for a downhole perforating tool and method of retrieving the same

Abstract

The application provides a short section for a downhole perforating tool and a recovery method thereof. The short section comprises a first hydraulic cylinder, an output end of a second hydraulic cylinder, and a pushing element, the drill bit is connected to the first hydraulic cylinder, the pushing element is connected to the second hydraulic cylinder, the drill bit is connected to the first hydraulic cylinder through an extension oil passage, a reset oil passage is connected to the first hydraulic cylinder, the reset oil passage is connected to a pressure storage cavity of a pressure storage assembly through a first pipeline, the reset oil passage is connected to a first port of a shunt pipe through a second pipeline, a second port and a third port of the shunt pipe are connected to a reset cavity of the second hydraulic cylinder and the reset oil passage respectively, a one-way valve assembly is arranged in the shunt pipe, and a pushing extension oil passage is connected to a hydraulic cavity of the second hydraulic cylinder. According to the shunt pipe and the one-way valve assembly, the hydraulic oil and the hydraulic potential energy are temporarily stored in the normal operation process through the pressure storage assembly, on the basis of the hydraulic oil supply in the same reset oil passage, the first hydraulic cylinder is subjected to double pressurization of the reset oil passage and the pressure storage assembly, and the problem that the pushing element is recovered earlier than the drill bit is avoided.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, and specifically relates to a short section for downhole drilling tools and its recovery method. Background Technology

[0002] In oil well logging operations, small-diameter electro-hydraulic perforating tools have technical advantages such as small diameter, high perforation efficiency, and multiple perforations in a single well run when used for perforation operations inside pipes. However, considering the complex downhole environment and perforation reliability, it is necessary to fully consider the need for rapid retrieval of perforating tools in order to avoid causing secondary complex accidents.

[0003] However, in the current process of retrieving the entire drilling device, the conventional retrieval sequence is: first, the support components used to support the drilling device are retrieved, and then the drill bit is retrieved, or the support components and the drill bit are retrieved simultaneously. However, this will cause the drill bit to lose its vertical support before the retrieval is completed, which can easily cause the drill bit to shift in position in the vertical direction, leading to the problem of the drill bit getting stuck. This is especially true in emergency situations such as power outages, where it is even more difficult to ensure safety.

[0004] Therefore, overcoming the shortcomings of the existing technology is an urgent problem to be solved in this technical field. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a short section for a downhole drilling tool, comprising: a body and a first hydraulic cylinder, a second hydraulic cylinder, and a pressure accumulator embedded in the body;

[0006] The body is equipped with a push-out oil circuit, a drill bit extension oil circuit, and a reset oil circuit that connect to the external oil supply equipment. The output ends of the first hydraulic cylinder and the second hydraulic cylinder are respectively connected to the drill bit and the push-out component.

[0007] The drill bit extends out of the oil passage and connects to the hydraulic chamber of the first hydraulic cylinder through the pipeline. The reset chamber of the first hydraulic cylinder is connected to the reset oil passage. The reset oil passage connects to the accumulator chamber of the accumulator assembly through the first pipeline. The reset oil passage connects to the first port of the shunt pipe through the second pipeline. The second port and the third port of the shunt pipe are respectively connected to the reset chamber and the reset oil passage of the second hydraulic cylinder through pipelines.

[0008] The shunt pipe is equipped with a one-way valve assembly to prevent hydraulic oil from entering the inner cavity of the shunt pipe from the first port;

[0009] The hydraulic passage extends outwards and is connected to the hydraulic chamber of the second hydraulic cylinder via a pipeline.

[0010] Furthermore, the body includes a short section body and a push-fit body. One end of the short section body has an installation port, and one end of the push-fit body is inserted into the installation port to form a sleeve with the short section body. The other end of the push-fit body can be detachably installed with a pressure accumulator assembly.

[0011] The first hydraulic cylinder is mounted on the short section body, and the second hydraulic cylinder is mounted on the push-assist body and extends in the opposite direction to the first hydraulic cylinder.

[0012] Furthermore, the diverter includes a coaxially sleeved and hollow valve body and valve seat, with the free end ports of the valve body and valve seat being the first port and the second port, respectively;

[0013] The one-way valve assembly includes a valve core and a steel ball built into the valve body cavity. One end of the valve core faces the first port, and the other end of the valve core abuts against one side of the steel ball. A spring is sleeved on the outer wall of the valve core to connect the outer wall of the valve core and the side wall of the valve body cavity, so as to push the valve core to squeeze the steel ball to block the valve seat cavity port.

[0014] The valve seat is provided with a vertical port that connects to the inner cavity, and the vertical port is the third port.

[0015] Furthermore, the compressive force of the spring on the steel ball is less than the force of the hydraulic oil in the reset line, and the diameters of both the valve core and the steel ball are smaller than the diameter of the valve body cavity.

[0016] Furthermore, the outer walls of the free ends of the valve body and valve seat are fitted with sealing rings, which are respectively embedded in the short section body and the push body.

[0017] Furthermore, the accumulator assembly includes: a valve seat, a resilient component, and a bottom cone;

[0018] The end of the push-abutment body away from the short section body has an installation slot. The port of the installation slot is detachably sleeved with a bottom cone. The side of the bottom cone facing the installation slot is connected to one end of the valve seat through an elastic component. The other end of the valve seat is slidably sleeved with the inner wall of the installation slot. The valve seat and the bottom surface of the installation slot maintain a predetermined distance to form the accumulator chamber of the accumulator assembly.

[0019] Furthermore, the valve seat is embedded with an overflow valve that connects to the accumulator chamber, and the output end of the overflow valve is connected to an external oil tank through a pipeline.

[0020] Furthermore, the elastic component includes a disc spring and a disc spring seat fitted inside the disc spring.

[0021] Furthermore, one end of the bottom cone is inserted into the mounting slot, and the side wall of the bottom cone inserted into the mounting slot is provided with a first threaded ring that forms a threaded ring connection with the inner wall of the mounting slot;

[0022] The side wall of the push-fit body inserted into the installation port is provided with a second threaded ring that forms a threaded connection with the inner wall of the installation port.

[0023] Furthermore, it also includes an oil circuit connector, with sealing rings fitted on the outer walls of both ends of the oil circuit connector, and respectively embedded in the short section body and the push-fit body to connect the first pipeline inside the short section body and the push-fit body.

[0024] The present invention also proposes a method for recovering the aforementioned short section used in downhole drilling tools, the recovery method comprising:

[0025] When drilling is completed, the injection of hydraulic oil into the push-out oil passage and the drill bit extension oil passage is cancelled. Hydraulic oil is injected into the reset oil passage to the third port of the shunt pipe. The hydraulic oil flows out from the first port, passes through the second pipeline and the reset oil passage to the reset chamber of the first hydraulic cylinder, drives the first hydraulic cylinder to reset and drives the drill bit to reset. The hydraulic oil flows out from the second port to the reset chamber of the second hydraulic cylinder, drives the second hydraulic cylinder to reset and drives the push-out component to reset.

[0026] At the same time, the hydraulic oil in the accumulator chamber of the accumulator assembly reaches the reset chamber of the first hydraulic cylinder through the first pipeline and the reset oil passage, driving the first hydraulic cylinder to reset and increasing the drill bit reset rate.

[0027] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0028] The short section for downhole drilling tools of this application integrates the drill bit and the pusher by incorporating a first hydraulic cylinder and a second hydraulic cylinder on the main body, improving the overall compactness of the tool structure and shortening its overall length. With the configuration of the shunt pipe and one-way valve assembly, and by using a accumulator assembly, hydraulic oil and its hydraulic potential energy are temporarily stored during normal operation. Based on the hydraulic oil supply from the same reset oil circuit, during normal reset operations, the reset chamber of the first hydraulic cylinder receives hydraulic oil from both the reset oil circuit and the accumulator assembly. This achieves a dual pressurization effect within the reset chamber of the first hydraulic cylinder, ensuring that drill bit retrieval takes precedence over pusher retrieval, thus preventing tool instability and stuck drill damage caused by the pusher retrieving before the drill bit.

[0029] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic diagram of a short section for a downhole drilling tool in an embodiment of the present invention is shown. Figure 1 ;

[0032] Figure 2 A schematic diagram of a short section for a downhole drilling tool in an embodiment of the present invention is shown. Figure 2 ;

[0033] Figure 3 A schematic diagram of the shunt tube in an embodiment of the present invention is shown;

[0034] Figure 4 A schematic diagram of the structure of the accumulator assembly in an embodiment of the present invention is shown;

[0035] Figure 5 A schematic diagram of the oil passage distribution of a short section used for a downhole perforation tool in an embodiment of the present invention is shown;

[0036] Figure 6 A schematic diagram of a short section for a downhole drilling tool in an embodiment of the present invention is shown. Figure 3 .

[0037] In the figure, the components are: body 1, short body 101, push-fit body 102, diverter pipe 2, valve body 201, valve seat 202, valve core 203, steel ball 204, spring 205, first hydraulic cylinder 3, second hydraulic cylinder 4, accumulator assembly 5, valve seat 501, disc spring 502, disc spring seat 503, bottom cone 504, overflow valve 505, drill bit 6, push-fit component 7, reset oil passage 8, first pipeline 9, second pipeline 10, third pipeline 11, mounting port 12, mounting slot 13, first threaded ring 14, second threaded ring 15, oil circuit connector 16, push-fit extension oil passage 17, drill bit extension oil passage 18, and reset oil passage 19. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention provides a short section for downhole drilling tools. Figure 1 A schematic diagram of a short section for a downhole drilling tool according to an embodiment of the present invention is shown. Figure 1 , Figure 1 The short section used for downhole drilling tools includes: a body 1 and a first hydraulic cylinder 3, a second hydraulic cylinder 4, and a pressure accumulator 5 embedded in the body 1;

[0040] The main body 1 is equipped with a push-out oil passage 17, a drill bit extension oil passage 18, and a reset oil passage 19 that are connected to an external oil supply device. The output ends of the first hydraulic cylinder 3 and the second hydraulic cylinder 4 are respectively connected to the drill bit 6 and the push-out component 7.

[0041] The drill bit extends out of the oil passage 18 and is connected to the hydraulic chamber of the first hydraulic cylinder 3 through a pipeline. The reset chamber of the first hydraulic cylinder 3 is connected to the reset oil passage 8. The reset oil passage 8 is connected to the accumulator chamber of the accumulator assembly 5 through the first pipeline 9. The reset oil passage 8 is connected to the first port of the shunt pipe 2 through the second pipeline 10. The second port and the third port of the shunt pipe 2 are connected to the reset chamber and reset oil passage 19 of the second hydraulic cylinder 4 through pipelines, respectively.

[0042] The diverter pipe 2 is equipped with a one-way valve assembly to prevent hydraulic oil from entering the inner cavity of the diverter pipe 2 from the first port;

[0043] The hydraulic chamber of the second hydraulic cylinder 4 is connected to the extended oil passage 17 through the pipeline.

[0044] The short section for the downhole drilling tool of this application integrates the drill bit 6 and the pusher 7 by setting a first hydraulic cylinder 3 and a second hydraulic cylinder 4 on the body 1, which improves the compactness of the overall tool structure and shortens the overall length of the tool. By using the accumulator 5, the hydraulic oil and its hydraulic potential energy are temporarily stored during normal operation. With the setting of the shunt pipe 2, the high pressure oil generated in the accumulator chamber of the accumulator 5 can only reach the reset chamber of the first hydraulic cylinder 3, which ensures that the downhole drilling tool meets the operational requirements of automatic retraction of the drill bit 6 in the event of power failure and avoids secondary accidents caused by stuck drill.

[0045] Furthermore, based on the same reset oil circuit 19, during the normal reset process, the reset chamber of the first hydraulic cylinder 3 can not only obtain hydraulic oil supply from the reset oil circuit 19, but also obtain hydraulic oil supply from the accumulator component 5. This enables the reset chamber of the first hydraulic cylinder 3 to achieve a dual pressurization effect from the reset oil circuit 19 and the accumulator component 5, ensuring that the drill bit 6 is retracted before the pusher 7, thus avoiding the problem of tool instability and drill jamming caused by the pusher 7 retracting before the drill bit 6.

[0046] Specifically, in order to further improve the convenience of the production process of the device of this application, the whole is decomposed into a short section body 101 and a push-fit body 102. One end of the short section body 101 is provided with an installation port 12, and one end of the push-fit body 102 is inserted into the installation port 12 to form a sleeve with the short section body 101. The other end of the push-fit body 102 can be detachably installed with a pressure accumulator 5. This is equivalent to dividing the whole device into three components, realizing a modular design and meeting the needs of rapid assembly and disassembly.

[0047] Correspondingly, the first hydraulic cylinder 3 is installed on the short section body 101, and the second hydraulic cylinder 4 is installed on the push-fit body 102. Based on the fact that the output ends of the first hydraulic cylinder 3 and the second hydraulic cylinder 4 are respectively connected to the drill bit 6 and the push-fit component 7, the modular design requirements of the drill bit 6 and the push-fit component 7 are met. Moreover, the working ends of the second hydraulic cylinder 4 and the first hydraulic cylinder 3 are in opposite extension and retraction directions, so as to ensure that the force generated by the push-fit component 7 driven by the second hydraulic cylinder 4 to form abutment against the inner wall of the oil pipe is opposite to the thrust force when the drill bit 6 is driven by the first hydraulic cylinder 3 to perform drilling operations, thus ensuring the stability of the drilling operation.

[0048] exist Figure 3 In the example shown, the diversion pipe 2 includes a valve body 201 and a valve seat 202 that are coaxially connected. Both the valve body 201 and the valve seat 202 are hollow. The inner cavity of the valve body 201 and the inner cavity of the valve seat 202 are connected and together form a flow channel.

[0049] Correspondingly, the free end ports of valve body 201 and valve seat 202 are the first port and the second port, respectively.

[0050] The one-way valve assembly includes a valve core 203 and a steel ball 204 built into the inner cavity of the valve body 201. One end of the valve core 203 faces the first port, and the other end of the valve core 203 abuts against one side of the steel ball 204. A spring 205 is sleeved on the outer wall of the valve core 203 to connect the outer wall of the valve core 203 and the side wall of the inner cavity of the valve body 201, so as to push the valve core 203 to squeeze the steel ball 204 to block the inner cavity port of the valve seat 202.

[0051] The valve seat 202 is provided with a vertical port that connects to the inner cavity, and the vertical port is the third port.

[0052] refer to Figure 1 , Figure 3 , Figure 5 and Figure 6 During the outward extension of the drive drill bit 6 and the pusher 7, hydraulic oil is injected into the hydraulic chamber of the first hydraulic cylinder 3 through the pusher extension oil passage 17 until the hydraulic chamber is connected to one end of the reset oil passage 8, thereby causing the hydraulic oil in the hydraulic chamber of the first hydraulic cylinder 3 to flow into the reset oil passage 8. Figure 1In the example shown, the first pipeline 9 and the second pipeline 10 are respectively arranged on one side of the reset oil passage 8 and are distributed in parallel.

[0053] Among them, the first port of the diversion pipe 2 connected to the second pipeline 10, the hydraulic oil flowing to the first port pushes the valve core 203 and the steel ball 204 to the right, further improving the sealing performance of the steel ball 204 on the inner port of the valve seat 202, and preventing the hydraulic oil from flowing to the second port and the third port;

[0054] The first pipeline 9 is connected to the accumulator chamber of the accumulator assembly 5. The hydraulic oil entering the accumulator chamber of the accumulator assembly 5 will be temporarily stored in the accumulator chamber to form high-pressure oil.

[0055] During the process of the drive drill bit 6 and the pusher 7 retracting inward;

[0056] During normal recovery operations, the push-adhesion oil passage 17 and drill bit extension oil passage 18 stop the operation, and the reset oil passage 19 delivers the oil to the third port of the diversion pipe 2.

[0057] After the reset hydraulic oil is injected into the third port through the reset oil circuit 19, it is split into left and right sides. Figure 1 The left-hand flow channel flows to the first port until the reset chamber of the first hydraulic cylinder 3, and the right-hand flow channel flows to the second port until the reset chamber of the second hydraulic cylinder 4.

[0058] During the process of the reset hydraulic oil flowing from the third port to the first port, the reset hydraulic oil impacts the steel ball 204, pushing the steel ball 204 to the left, while causing the spring 205 to undergo compression deformation, thereby unsealing the inner cavity port of the valve seat 202 and realizing the reset operation of the first hydraulic cylinder 3 and the second hydraulic cylinder 4.

[0059] At this time, the hydraulic oil in the accumulator chamber of the accumulator component 5 will also output hydraulic oil to the reset chamber of the first hydraulic cylinder 3, increasing the input amount and input pressure of the hydraulic oil in the reset chamber of the first hydraulic cylinder 3, so as to achieve the effect of preferential retraction of the drill bit 6 and protect the drill bit 6.

[0060] It should be further explained that the squeezing force of the spring 205 on the steel ball 204 is less than the force of the hydraulic oil in the reset line. At the same time, the diameters of the valve core 203 and the steel ball 204 are both smaller than the inner diameter of the valve body 201, so as to ensure that the reset hydraulic oil input from the reset hydraulic oil can break through the blockage of the steel ball 204 on the inner port of the valve seat 202.

[0061] Furthermore, in this embodiment, the cross-section of the valve core 203 adopts a T-shaped structure so that the protruding part of the valve core 203 can be adapted to abut against the spring 205.

[0062] Combination Figure 1The outer walls of the free ends of the valve body 201 and valve seat 202 are fitted with sealing rings, which are respectively embedded in the short section body 101 and the push body 102, thereby ensuring the continuity and sealing of the internal pipeline of the body 1.

[0063] refer to Figure 4 The pressure accumulator assembly 5 includes: valve seat 501, elastic component, and bottom cone 504;

[0064] The end of the push-abutment body 102 away from the short section body 101 is provided with a mounting slot 13. The port of the mounting slot 13 is detachably sleeved with a bottom cone 504. The side of the bottom cone 504 facing the mounting slot 13 is connected to one end of the valve seat 501 through an elastic component. The other end of the valve seat 501 is slidably sleeved with the inner wall of the mounting slot 13. The valve seat 501 and the inner bottom surface of the mounting slot 13 maintain a predetermined distance to form the pressure accumulator chamber of the pressure accumulator assembly 5.

[0065] After the hydraulic oil in the reset chamber of the first hydraulic cylinder 3 enters the accumulator chamber of the accumulator assembly 5 through the reset oil passage 8 and the first pipeline 9, Figure 4 In the example shown, the hydraulic oil pushes the valve seat 501 to the right, which in turn compresses the elastic component, converting the hydraulic potential energy into the elastic potential energy of the elastic component.

[0066] When both the push-out extension oil passage 17 and the drill bit extension oil passage 18 stop operating, the elastic component that has lost its compression undergoes reset deformation, thereby converting elastic potential energy into hydraulic potential energy. The hydraulic oil in the accumulator chamber of the compression accumulator 5 enters the reset chamber of the first hydraulic cylinder 3 through the first pipeline 9 and the reset oil passage 8, driving the first hydraulic cylinder 3 to reset so as to drive the drill bit 6 to retract.

[0067] It should be noted that during the assembly of the accumulator component 5, the valve seat 501, the elastic component, and the bottom cone 504 are installed sequentially in the mounting slot 13. The pressure of the accumulator can be adjusted by selecting the specifications of the elastic component and the compression amount of the elastic component by the bottom cone 504, based on the pressure requirements of the accumulator chamber. The bottom cone 504 can also be used to pre-tighten the elastic component to facilitate debugging and testing.

[0068] In addition, the valve seat 501 is embedded with an overflow valve 505 that connects to the accumulator chamber of the accumulator assembly 5. The output end of the overflow valve 505 is connected to an external oil tank through a pipeline, so that the accumulator chamber of the accumulator assembly 5 has the function of automatic pressure protection to ensure the controllability of the accumulator pressure. After the hydraulic oil enters the accumulator chamber, according to the predetermined pressure value of the overflow valve 505, when the pressure of the hydraulic oil input reaches the pressure value of the overflow valve 505, the overflow valve 505 is opened, and the pressure of the accumulator chamber will be maintained at that pressure value. The excess hydraulic oil will be transported to the external oil tank through the output end of the overflow valve 505 and the corresponding pipeline, thereby making the hydraulic pressure in the accumulator chamber continuously maintain a stable hydraulic pressure and improving the sealing reliability of the accumulator assembly 5.

[0069] Specifically, the elastic components include a disc spring 502 and a disc spring seat 503 fitted inside the disc spring 502.

[0070] The modular disc spring assembly design allows for adjustment of the combination of disc spring 502 and disc spring seat 503 according to actual needs, in order to adapt to different reset force requirements. The reset force can be changed simply by adjusting the combination of the disc spring assembly.

[0071] At the same time, there is no rotational friction between the disc springs, which helps to keep the hydraulic oil inside the tool clean.

[0072] It should be noted that the specific preset pressure value of the accumulator chamber in this application is determined by the pressure value of the relief valve 505, and the hydraulic oil volume of the accumulator chamber is determined by the deformation of the elastic component.

[0073] When it is necessary to adjust the performance of the accumulator component 5, the specific maximum hydraulic oil volume and the maximum pressure value of the accumulator chamber are crucial. The former determines the retrieval stroke of the drill bit 6, while the latter determines the retrieval speed and retrieval effect of the drill bit 6. When the pressure is low, the drill bit 6 will not be retrieved due to the resistance of stuck drill bit, and when the oil volume is low, the drill bit 6 can only be retrieved a certain distance.

[0074] exist Figure 2 In the example shown, one end of the bottom cone 504 is inserted into the mounting slot 13, and the side wall of the bottom cone 504 inserted into the mounting slot 13 is provided with a first threaded ring 14 that forms a threaded connection with the inner wall of the mounting slot 13.

[0075] The push-back body 102 is inserted into the side wall of the mounting port 12 and is provided with a second threaded ring 15 that forms a threaded connection with the inner wall of the mounting port 12.

[0076] The first helical ring 14 prevents the disc spring 502 from rotating during disassembly, reducing frictional motion and minimizing impurities generated by friction within the tool.

[0077] Similarly, the second helical ring 15 ensures that the push-body 102 only undergoes axial movement during disassembly, which helps to keep the hydraulic oil inside the tool clean and reduce wear between structures.

[0078] Specifically, it also includes an oil line connector 16, with sealing rings fitted on the outer walls of both ends of the oil line connector 16, and respectively embedded in the short section body 101 and the push body 102 to connect the first pipeline 9 inside the short section body 101 and the push body 102, thereby improving the tightness of the connection between the first pipeline 9 inside the short section body 101 and the push body 102.

[0079] Correspondingly, in order to ensure the reliability of the adjustable device in this embodiment, O-ring sealing structures are provided at the corresponding positions of the connection ends of each component.

[0080] To better illustrate the oil circuit of the device in this application, refer to... Figure 5 , Figure 5 A schematic diagram of the oil passage distribution of a short section used for a downhole perforation tool in an embodiment of the present invention is shown.

[0081] During normal use, hydraulic oil is input from the drill bit extension oil passage 18 into the hydraulic chamber of the first hydraulic cylinder 3, driving the drill bit 6 to extend until the hydraulic oil is connected to the reset oil passage 8. At this time, the hydraulic oil flows through the reset oil passage 8 and the first pipeline 9 to the accumulator chamber of the accumulator assembly 5. Meanwhile, excess hydraulic oil will be transported to the oil tank through the overflow valve 505 of the accumulator assembly 5.

[0082] Hydraulic oil is input into the hydraulic chamber of the second hydraulic cylinder 4 through the push-out extension oil passage 17, driving the push-out member 7 to extend outward;

[0083] It should be noted that, in consideration of the detection of the internal oil circuit of the device in this application, a third pipeline 11 is added to connect to the reset oil passage 8, and a manual pressure relief valve is provided on the third pipeline 11. The output end of the third pipeline 11 is connected to the oil tank.

[0084] During normal recovery operations, the push-adhesion extension oil passage 17 and drill bit extension oil passage 18 stop the operation. The reset oil passage 19 delivers oil to the third port of the diversion pipe 2, and simultaneously diverts it to the first port and the second port to achieve the reset operation of the first hydraulic cylinder 3 and the second hydraulic cylinder 4. However, under the action of the accumulator component 5, the hydraulic oil in the accumulator chamber will increase the input amount and input pressure of the hydraulic oil in the reset chamber of the first hydraulic cylinder 3, still achieving the effect of preferential retraction of the drill bit 6, thus protecting the drill bit 6.

[0085] It should be noted that in the event of a power outage or other abnormality, pushing and pulling the extension oil passage 17, the drill bit extension oil passage 18, and the reset oil passage 19 will all stop the operation.

[0086] The accumulator component 5 of this application will still reset due to the loss of compression, thereby converting elastic potential energy into hydraulic potential energy, and compressing the hydraulic oil in the accumulator chamber of the accumulator component 5. At this time, under the action of the steel ball 204 inside the diverter pipe 2, after the hydraulic oil enters the first port, the steel ball 204 will still maintain the blockage of the valve seat 202 inner port. The hydraulic oil in the accumulator chamber of the accumulator component 5 will only enter the reset chamber of the first hydraulic cylinder 3 through the first pipeline 9 and the reset oil passage 8, driving the first hydraulic cylinder 3 to reset. The automatic retraction operation of the drill bit 6 ensures that the drill bit 6 is still protected under abnormal conditions. Therefore, the short circuit of this application has the effect of prioritizing the recovery of the drill bit 6 under both normal and abnormal conditions.

[0087] This invention also discloses a method for recovering the aforementioned short section used in downhole drilling tools, the method comprising:

[0088] When the drilling operation is completed, the injection of hydraulic oil into the push-out oil passage 17 and the drill bit extension oil passage 18 is cancelled. Hydraulic oil is injected into the reset oil passage 19 to the third port of the shunt pipe 2. The hydraulic oil flows out from the first port, passes through the second pipeline 10 and the reset oil passage 8 to reach the reset chamber of the first hydraulic cylinder 3, drives the first hydraulic cylinder 3 to reset and drives the drill bit 6 to reset. The hydraulic oil flows out from the second port to reach the reset chamber of the second hydraulic cylinder 4, drives the second hydraulic cylinder 4 to reset and drives the push-out component 7 to reset.

[0089] At the same time, the hydraulic oil in the accumulator chamber of the accumulator component 5 reaches the reset chamber of the first hydraulic cylinder 3 through the first pipeline 9 and the reset oil passage 8, driving the first hydraulic cylinder 3 to reset and increasing the reset rate of the drill bit 6.

[0090] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of multiple components or the interaction between multiple components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0091] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A short section for a downhole drilling tool, characterized in that, include: The main body (1) and the first hydraulic cylinder (3), the second hydraulic cylinder (4), and the accumulator assembly (5) embedded in the main body (1); The main body (1) is provided with a push-out oil passage (17), a drill bit extension oil passage (18), and a reset oil passage (19) that are connected to an external oil supply device. The output ends of the first hydraulic cylinder (3) and the second hydraulic cylinder (4) are respectively connected to the drill bit (6) and the push-out component (7). The drill bit extends out of the oil passage (18) and is connected to the hydraulic chamber of the first hydraulic cylinder (3) through a pipeline. The reset chamber of the first hydraulic cylinder (3) is connected to the reset oil passage (8). The reset oil passage (8) is connected to the accumulator chamber of the accumulator assembly (5) through the first pipeline (9). The reset oil passage (8) is connected to the first port of the shunt pipe (2) through the second pipeline (10). The second port and the third port of the shunt pipe (2) are connected to the reset chamber and the reset oil passage (19) of the second hydraulic cylinder (4) through pipelines, respectively. The diversion pipe (2) is equipped with a one-way valve assembly to prevent hydraulic oil from entering the inner cavity of the diversion pipe (2) from the first port; The push-out oil passage (17) is connected to the hydraulic chamber of the second hydraulic cylinder (4) through a pipeline.

2. The short section for downhole drilling tools according to claim 1, characterized in that, The main body (1) includes a short section body (101) and a push-in body (102). One end of the short section body (101) is provided with an installation port (12). One end of the push-in body (102) is inserted into the installation port (12) and forms a sleeve with the short section body (101). The other end of the push-in body (102) can be detachably installed with a pressure accumulator (5). The first hydraulic cylinder (3) is mounted on the short section body (101), and the second hydraulic cylinder (4) is mounted on the push body (102) and has an extension and retraction direction opposite to that of the working end of the first hydraulic cylinder (3).

3. The short section for downhole drilling tools according to claim 2, characterized in that, The diversion pipe (2) includes a coaxially sleeved and hollow valve body (201) and valve seat (202), with the free end ports of the valve body (201) and valve seat (202) being the first port and the second port, respectively; The one-way valve assembly includes a valve core (203) and a steel ball (204) built into the inner cavity of the valve body (201). One end of the valve core (203) faces the first port, and the other end of the valve core (203) abuts against one side of the steel ball (204). A spring (205) is sleeved on the outer wall of the valve core (203) to connect the outer wall of the valve core (203) and the side wall of the inner cavity of the valve body (201) so as to push the valve core (203) to squeeze the steel ball (204) to block the inner cavity port of the valve seat (202). The valve seat (202) is provided with a vertical port that communicates with the inner cavity, and the vertical port is the third port.

4. The short section for downhole drilling tools according to claim 3, characterized in that, The squeezing force of the spring (205) on the steel ball (204) is less than the force of the hydraulic oil in the reset pipe (19), and the diameters of the valve core (203) and the steel ball (204) are both smaller than the inner diameter of the valve body (201).

5. The short section for downhole drilling tools according to claim 4, characterized in that, The valve body (201) and valve seat (202) are both fitted with sealing rings on the outer walls of their free ends and are respectively embedded in the short section body (101) and the push body (102).

6. The short section for downhole drilling tools according to claim 2, characterized in that, The pressure accumulator assembly (5) includes: a valve seat (501), an elastic component, and a bottom cone (504); The push-in body (102) has an installation slot (13) at one end away from the short section body (101). The port of the installation slot (13) is detachably sleeved with a bottom cone (504). The side of the bottom cone (504) facing the installation slot (13) is connected to one end of the valve seat (501) through an elastic component. The other end of the valve seat (501) is slidably sleeved with the inner wall of the installation slot (13). The valve seat (501) and the bottom surface of the installation slot (13) maintain a predetermined distance to form the pressure accumulator chamber of the pressure accumulator assembly (5).

7. The short section for a downhole drilling tool according to claim 6, characterized in that, The valve seat (501) is embedded with an overflow valve (505) that connects to the accumulator chamber of the accumulator assembly (5). The output end of the overflow valve (505) is connected to an external oil tank through a pipeline.

8. The short section for a downhole drilling tool according to claim 6, characterized in that, The elastic component includes a disc spring (502) and a disc spring seat (503) sleeved on the inner ring of the disc spring (502).

9. The short section for a downhole drilling tool according to claim 8, characterized in that, One end of the bottom cone (504) is inserted into the mounting slot (13), and the side wall of the bottom cone (504) inserted into the mounting slot (13) is provided with a first threaded ring (14) that forms a threaded ring connection with the inner wall of the mounting slot (13); The push body (102) is inserted into the side wall of the mounting port (12) and is provided with a second threaded ring (15) that forms a threaded connection with the inner wall of the mounting port (12).

10. The short section for a downhole drilling tool according to claim 2, characterized in that, It also includes an oil line connector (16), with sealing rings fitted on the outer walls of both ends of the oil line connector (16), and respectively embedded in the short section body (101) and the push body (102) to connect the first pipeline (9) inside the short section body (101) and the push body (102).

11. A method for recovering a sub-section of a downhole drilling tool according to any one of claims 1-10, characterized in that, The recycling method includes: When the drilling operation is completed, the injection of hydraulic oil into the push-out oil passage (17) and the drill bit extension oil passage (18) is cancelled. Hydraulic oil is injected into the reset oil passage (19) to the third port of the shunt pipe (2). The hydraulic oil flows out from the first port, passes through the second pipeline (10) and the reset oil passage (8) to reach the reset chamber of the first hydraulic cylinder (3), drives the first hydraulic cylinder (3) to reset and drives the drill bit (6) to reset. The hydraulic oil flows out from the second port to reach the reset chamber of the second hydraulic cylinder (4), drives the second hydraulic cylinder (4) to reset and drives the push-out part (7) to reset. At the same time, the hydraulic oil in the accumulator chamber of the accumulator assembly (5) passes through the first pipeline (9) and the reset oil passage (8) to reach the reset chamber of the first hydraulic cylinder (3), driving the first hydraulic cylinder (3) to reset and increasing the reset rate of the drill bit (6).

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