MWD naked eye salvage tool and use method

Abstract

The present invention discloses an MWD open-hole salvage tool and a method of using the tool, which belongs to the technical field of horizontal well drilling, and is characterized in that it comprises a guide tube, an extension tube and a joint tube, one end of the guide tube is connected to one end of the extension tube, the other end of the extension tube is connected to the joint tube, and a joint device for connecting to a salvage head of an MWD instrument is arranged in the joint tube. The present invention can ensure that the entire MWD instrument is not easily squeezed by other external forces during salvage, thereby reducing the probability of the MWD instrument being broken and improving the safety and success rate of salvage.

Description

Technical Field

[0001] The present invention relates to the technical field of horizontal well drilling, and in particular to an MWD open hole fishing tool and a use method thereof. Background Art

[0002] There are many horizontal wells with an inclination of more than 90°. The target layer thickness is only 3-5m, and the horizontal section exceeds 2500m. However, this also increases the frequency of drill bit sticking during drilling, and the drill bit sticking treatment takes a long time and is difficult. Downhole tools in many wells are buried, including MWD instruments, that is, measurement while drilling instruments.

[0003] Since the MWD instrument is expensive and has a small outer diameter, it is easy to tip over on the well wall. It is also a precision instrument made of low-strength materials with low pressure resistance, making it difficult to salvage. Conventional salvage tools use buckles or other forms of salvage, which can easily break the MWD instrument, resulting in poor salvage safety.

[0004] A Chinese patent document with publication number CN212079252U and publication date December 4, 2020 discloses a key-type MWD open-hole salvage device, characterized in that it includes a clamping tube assembly connected to a drill pipe for clamping fallen fish, and the free end of the clamping tube assembly is detachably connected to a guide tube through an extension tube; the clamping tube assembly includes a cylinder body connected to the extension tube, and one end of the cylinder body away from the extension tube is connected to a catching cava through a positioning bearing tray, and the positioning bearing tray is connected to the inner wall of the cylinder by a key; the extension tube is threadedly connected to the clamping tube assembly through an internal thread, and the extension tube is threadedly connected to the guide tube through an external thread, and the thickness of both ends of the extension tube gradually increases toward the middle.

[0005] The key-type MWD open-hole salvage device disclosed in the patent document uses extension tubes of different lengths to detachably connect the clamping tube assembly and the guide tube, which is convenient for adapting to different depths of drilling for fish salvage work, and has a wide range of applications; and after the fish is clamped and fixed by the clamping tube assembly, the extension tube is disconnected from the clamping tube assembly, which is convenient for taking the fish out of the clamping tube assembly; the guide tube not only lengthens the length of this device, but also can guide the fish in the drilling well into the clamping tube assembly for clamping and fixing. However, the entire MWD instrument is easily squeezed by other external forces, thereby increasing the probability of the MWD instrument being broken, affecting the safety and success rate of salvage. Summary of the invention

[0006] In order to overcome the defects of the above-mentioned prior art, the present invention provides an MWD naked-hole salvage tool and a method of use. The present invention can ensure that the entire MWD instrument is not easily squeezed by other external forces during salvage, thereby reducing the probability of the MWD instrument being broken and improving the safety and success rate of salvage.

[0007] The present invention is achieved through the following technical solutions:

[0008] A MWD naked hole salvage tool, characterized in that it comprises a guide tube, an extension tube and a joint tube, one end of the guide tube is connected to one end of the extension tube, the other end of the extension tube is connected to the joint tube, and a joint device for connecting to a salvage head of an MWD instrument is arranged in the joint tube.

[0009] The connector device comprises a main body and a clamping device, wherein the clamping device is connected to one end of the main body and is used for connecting with a fishing head of an MWD instrument.

[0010] The clamping device comprises two symmetrically arranged slips, through grooves adapted to the slips are symmetrically provided on both sides of the main body, the slips slide in the through grooves, and the main body is also provided with a limiting device for limiting the movement of the slips.

[0011] The limiting device is a first spring, the top of the slip and the top of the through groove are both inclined, a first groove is opened in the middle of the main body around the main body, a second groove is opened in the middle of the slip, and a first spring is arranged in both the first groove and the second groove.

[0012] It also includes a buffer mechanism, which includes a guide rod and a second spring. The guide rod is arranged in the joint tube through a connecting base. A sliding groove is opened on the top of the guide rod. The main body slides on the guide rod through the sliding groove. The second spring is arranged between the bottom of the guide rod and the main body.

[0013] The joint device also includes a snap-in mechanism, which includes a connecting ring and a plurality of steel bars arranged on the connecting ring. The steel bars are arranged around the connecting ring and are bent inward to form a grabbing cavity for locking the fishing head of the MWD instrument.

[0014] It also includes a supporting cavity and a clamp head. The clamp head is arranged inside the supporting cavity, and the spring clamp mechanism is arranged at the bottom of the clamp head.

[0015] A clamp is arranged at one end of the clamp head away from the spring clamp mechanism, and a plurality of protrusions are arranged on the inner surface of the clamp.

[0016] The tails of the guide tube and the extension tube are both provided with a straightening seat.

[0017] A method for using an MWD naked hole salvage tool, characterized in that it comprises the following steps:

[0018] S01. Lower the MWD open hole salvage tool to 7-13m before the location of the MWD instrument;

[0019] S02, start the mud pump to circulate and discharge oil and gas, and record the drilling parameters related to hanging weight, lifting friction resistance, lowering friction resistance, rotation resistance, pump stroke and pump pressure;

[0020] S03, then start rotating the drilling tool and lower the MWD open hole fishing tool;

[0021] S04. When the pump pressure rises, continue to rotate and lower the MWD open hole salvage tool by 10-15 cm and observe the change of pump pressure;

[0022] S05. If the pump pressure continues to increase, pull out the MWD open-hole salvage tool;

[0023] S06. If the pump pressure does not change or decreases, repeat steps S03, S04 and S05 in sequence.

[0024] The beneficial effects of the present invention are mainly manifested in the following aspects:

[0025] 1. In the present invention, one end of the guide tube is connected to one end of the extension tube, and the other end of the extension tube is connected to the joint tube. A joint device for connecting to the salvage head of the MWD instrument is arranged in the joint tube. Compared with the prior art, the entire MWD instrument can be protected from being squeezed by other external forces during salvage, thereby reducing the probability of the MWD instrument being broken and improving the safety and success rate of salvage.

[0026] 2. In the present invention, the guide tube, the extension tube and the joint tube can all allow the salvage head of the MWD instrument to enter the interior thereof. The guide tube is arranged at the front end, the extension tube is arranged in the middle, and the joint tube is arranged at the rear end. Threaded connections can be used between adjacent components. A joint device connected to the salvage head of the MWD instrument is installed inside the joint tube. Since the guide tube, the extension tube and the joint tube support the MWD instrument, the MWD instrument is fixed in the joint tube through the salvage head of the MWD instrument, thereby being able to well protect the safety of the entire MWD instrument during the salvage process and avoid damage to the instrument.

[0027] 3. The overall structure of the salvaging tool of the present invention is reasonably designed, simple in structure, and convenient for salvaging.

[0028] 4. The present invention makes the whole salvaging process simple and easy to operate, which greatly improves the salvaging efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementations, wherein:

[0030] Figure 1 It is a structural schematic diagram of the present invention;

[0031] Figure 2 It is a structural schematic diagram of the main body of the present invention;

[0032] Figure 3 It is a structural schematic diagram of the righting seat of the present invention;

[0033] Figure 4 It is a schematic diagram of the installation of the body and slips of the present invention;

[0034] Figure 5 For the present invention Figure 4 A top view of

[0035] Figure 6 This is a schematic diagram of the structure of the slip of the present invention;

[0036] Figure 7 It is a structural schematic diagram of the fishing head of the present invention;

[0037] Figure 8 This is a schematic diagram of the structure of Embodiment 3 of the present invention;

[0038] Fig. 9 It is a structural schematic diagram of the ejection mechanism of the present invention;

[0039] Fig.10 is another structural schematic diagram of Embodiment 3 of the present invention;

[0040] Fig.11 It is a structural schematic diagram of the clamp of the present invention;

[0041] Fig.12 It is a structural schematic diagram of the clamp head of the present invention;

[0042] Markings in the figure: 1. guide tube, 2. straightening seat, 3. extension tube, 4. main body, 5. guide rod, 6. second spring, 7. first groove, 8. through groove, 9. joint tube, 10. slip, 11. first spring, 12. second groove, 13. fishing head, 14. connecting ring, 15. spring-clip mechanism, 16. clamp, 17. clamp head, 18. support cavity. DETAILED DESCRIPTION

[0043] Example 1

[0044] See also Figure 1-Figure 12 A MWD naked hole salvage tool comprises a guide tube 1, an extension tube 3 and a joint tube 9. The guide tube 1 is arranged at the head of the entire salvage tool, the extension tube 3 is arranged in the middle, and the joint tube 9 is arranged at the tail. The three are detachably connected by threads.

[0045] Among them, the guide tube 1, the extension tube 3 and the joint tube 9 are all hollow cylindrical structures. The diameter of the end of the guide tube 1 away from the extension tube 3 is larger than the diameter of the end connected to the extension tube 3, and a cross-section hook-shaped structure is adopted, which can better touch and guide the MWD instrument salvage head 13 to enter the guide tube 1.

[0046] The length of the extension tube 3 is selected according to the length of the MWD instrument to be salvaged, and can support a longer MWD instrument. The joint tube 9 is used to connect with the drill tool, and the drill tool provides power to move the entire salvage tool to the location of the MWD instrument. A joint device is installed in the joint tube 9, so that after the MWD instrument salvage head 13 enters the guide tube 1, the MWD instrument salvage head 13 is fixed by the joint device, thereby fixing the MWD instrument. When the entire salvage device is pulled out, the entire MWD instrument is taken out.

[0047] The above structure of the present invention mainly includes a guide tube 1, an extension tube 3 and a joint tube 9. The three parts can allow the MWD instrument salvage head 13 to enter the interior thereof. The guide tube 1 is arranged at the front end, the extension tube 3 is arranged in the middle, and the joint tube 9 is arranged at the tail end. Adjacent parts are connected by threads. A joint device connected to the MWD instrument salvage head 13 is installed inside the joint tube 9. When in use, the entire equipment is drilled down to a specified place for salvage. During the salvage process, the MWD instrument salvage head 13 enters the guide tube 1 as a guide, and then the MWD instrument gradually enters the guide tube 1, the extension tube 3 and the joint tube 9 through the MWD instrument salvage head 13. After the MWD instrument salvage head 13 is connected to the joint device, the entire device can be pulled out. Since the guide tube 1, the extension tube 3 and the joint tube 9 support the MWD instrument, the MWD instrument is fixed in the joint tube 9 through the MWD instrument salvage head 13, so that the entire MWD instrument is not easily squeezed by other external forces, thereby reducing the probability of the MWD instrument being broken.

[0048] In this embodiment, a stabilizing seat 2 is provided at the tail of the guide tube 1 and the extension tube 3. Since the size of the MWD instrument may be inconsistent with the diameters of the guide tube 1, the extension tube 3 and the joint tube 9, the extension tube 3 will repeatedly collide and shake in the guide tube 1 when the MWD instrument and the salvage head 13 enter, and it is not easy to align with the joint device inside the joint tube 9, which makes the connection work more time-consuming. The stabilizing seat 2 mainly includes an annular structure, on which a plurality of baffles are installed. The plurality of baffles form a circle at one end away from the annular structure, which is used for the MWD instrument and the salvage head 13 to pass through, and the direction in which the MWD instrument and the salvage head 13 enter is aligned with the joint device.

[0049] This embodiment is the most basic implementation method. Compared with the prior art, it can ensure that the entire MWD instrument is not easily squeezed by other external forces during salvage, thereby reducing the probability of the MWD instrument being broken and improving the safety and success rate of salvage.

[0050] Example 2

[0051] See also Figure 1-Figure 12A MWD naked hole salvage tool includes a guide tube 1, an extension tube 3 and a joint tube 9. The guide tube 1 is provided at the head of the entire salvage tool, the extension tube 3 is provided at the middle, and the joint tube 9 is provided at the tail. The three are detachably connected by threads. The guide tube 1, the extension tube 3 and the joint tube 9 are all hollow cylindrical structures. The diameter of the end of the guide tube 1 away from the extension tube 3 is larger than the diameter of the end connected to the extension tube 3. The cross-section hook-shaped structure is adopted, which can better touch and guide the MWD instrument salvage head 13 to enter the guide tube 1. The length of the extension tube 3 is selected according to the length of the MWD instrument to be salvaged, and can support a longer MWD instrument. The joint tube 9 is used to connect with the drill tool, and the drill tool provides power to move the entire salvage tool to the location of the MWD instrument. A joint device is installed in the joint tube 9, so that after the MWD instrument salvage head 13 enters the guide tube 1, the MWD instrument salvage head 13 is fixed by the joint device, thereby fixing the MWD instrument. When the entire salvage device is pulled out, the entire MWD instrument is taken out. A straightening seat 2 is provided at the tail end of the guide tube 1 and the extension tube 3. Since the size of the MWD instrument may be inconsistent with the diameters of the guide tube 1, the extension tube 3 and the joint tube 9, the extension tube 3 will repeatedly collide and shake in the guide tube 1 when the MWD instrument and the salvage head 13 enter, and it is not easy to align with the joint device inside the joint tube 9, which makes the connection work more time-consuming. The straightening seat 2 mainly includes an annular structure, on which a plurality of baffles are installed. The baffles form a circle at one end away from the annular structure for the MWD instrument and the salvage head 13 to pass through, so that the direction in which the MWD instrument and the salvage head 13 enter is aligned with the joint device.

[0052] The connector device includes a main body 4 and a clamping device. The main body 4 adopts a cylindrical structure with a hollow interior, which is convenient for connecting with the fishing head 13 of the MWD instrument. The clamping device is connected to one end of the main body 4 and is used to connect with the fishing head 13 of the MWD instrument.

[0053] More specifically, the clamping device includes two symmetrically arranged slips 10. Through grooves 8 corresponding to the slips 10 are also provided on both sides of the main body 4, so that the slips 10 can move in the through grooves 8. A protrusion is provided on the top of the slip 10, so that the distance between the initial positions of the two slips 10 is smaller than the diameter of the main body 4. The main body 4 is also provided with a limit device for limiting the movement of the slips 10. The limit device enables the slips 10 to return to their original position after being pushed by the salvaging head 13 of the MWD instrument, so as to achieve the purpose of locking the salvaging head 13 of the MWD instrument.

[0054] Among them, the limiting device includes a first spring 11, and a first groove 7 is opened in the middle of the main body 4 around the main body 4 to form an inwardly concave space for placing the first spring 11. At the same time, a second groove 12 is opened in the middle of the two slips 10, and the length of the second groove 12 is the same as that of the first spring 11. The first spring 11 is located in the first groove 7 and the second groove 12 at the same time, and the top of the slip 10 and the top of the through groove 8 are both inclined.

[0055] When in use, the salvaging head 13 of the MWD instrument will push the slips 10 on both sides to move away from the main body 4. Since the top of the slip 10 and the top of the through groove 8 are both inclined, the slip 10 starts to move downward as a whole, and the top of the second groove 12 starts to press the first spring 11 downward. Since the other end of the second spring 6 is restricted in the first groove 7, the first spring 11 starts to be compressed due to the squeezing of the second groove 12. After the salvaging head 13 of the MWD instrument is separated from the top of the slip 10, the first spring 11 releases its elastic force to restore the slip 10 to its original position.

[0056] In addition, in order to prevent it from being broken due to excessive bearing pressure, a buffer mechanism is also included. The buffer mechanism includes a guide rod 5 and a second spring 6. The guide rod 5 is arranged in the joint tube 9 through a connecting base. The connecting base is provided with a through hole for connecting air pressure. A sliding groove is opened at the bottom of the main body 4. The main body 4 slides on the guide rod 5 through the sliding groove. A second spring 6 is arranged between the bottom of the guide rod 5 and the main body 4.

[0057] This embodiment is another preferred implementation mode. The guide tube, the extension tube and the joint tube can all allow the fishing head of the MWD instrument to enter the interior thereof. The guide tube is arranged at the front end, the extension tube is arranged in the middle, and the joint tube is arranged at the rear end. Threaded connections can be used between adjacent components. A joint device connected to the fishing head of the MWD instrument is installed inside the joint tube. Since the guide tube, the extension tube and the joint tube support the MWD instrument, the MWD instrument is fixed in the joint tube through the fishing head of the MWD instrument, so that the safety of the entire MWD instrument can be well protected during the salvage process to avoid damage to the instrument.

[0058] Example 3

[0059] See also Figure 1-Figure 12A MWD naked hole salvage tool includes a guide tube 1, an extension tube 3 and a joint tube 9. The guide tube 1 is provided at the head of the entire salvage tool, the extension tube 3 is provided at the middle, and the joint tube 9 is provided at the tail. The three are detachably connected by threads. The guide tube 1, the extension tube 3 and the joint tube 9 are all hollow cylindrical structures. The diameter of the end of the guide tube 1 away from the extension tube 3 is larger than the diameter of the end connected to the extension tube 3. The cross-section hook-shaped structure is adopted, which can better touch and guide the MWD instrument salvage head 13 to enter the guide tube 1. The length of the extension tube 3 is selected according to the length of the MWD instrument to be salvaged, and can support a longer MWD instrument. The joint tube 9 is used to connect with the drill tool, and the drill tool provides power to move the entire salvage tool to the location of the MWD instrument. A joint device is installed in the joint tube 9, so that after the MWD instrument salvage head 13 enters the guide tube 1, the MWD instrument salvage head 13 is fixed by the joint device, thereby fixing the MWD instrument. When the entire salvage device is pulled out, the entire MWD instrument is taken out. A straightening seat 2 is provided at the tail end of the guide tube 1 and the extension tube 3. Since the size of the MWD instrument may be inconsistent with the diameters of the guide tube 1, the extension tube 3 and the joint tube 9, the extension tube 3 will repeatedly collide and shake in the guide tube 1 when the MWD instrument and the salvage head 13 enter, and it is not easy to align with the joint device inside the joint tube 9, which makes the connection work more time-consuming. The straightening seat 2 mainly includes an annular structure, on which a plurality of baffles are installed. The baffles form a circle at one end away from the annular structure for the MWD instrument and the salvage head 13 to pass through, so that the direction in which the MWD instrument and the salvage head 13 enter is aligned with the joint device.

[0060] Furthermore, the joint device includes a spring-cage mechanism 15, which includes a connecting ring 14 and a plurality of steel bars arranged on the connecting ring 14. The steel bars are arranged around the connecting ring 14 in a circle, and the steel bars are all bent inward to form a grabbing cavity for locking the MWD instrument salvaging head 13. The spring-cage mechanism 15 can fix the MWD instrument salvaging head 13 more firmly.

[0061] In order to achieve a better clamping effect, it also includes a supporting cavity 18 and a clamp head 17. The clamp head 17 is arranged inside the supporting cavity 18, and the movement of the clamp head 17 is limited by a limit baffle. The spring clamp mechanism 15 is arranged at the bottom of the clamp head 17.

[0062] In addition, a clamp 16 is provided at one end of the clamp head 17 away from the spring clamp mechanism 15, and a plurality of protrusions are provided inside the clamp 16, with certain gaps between the protrusions. When the MWD instrument salvage head 13 enters the inside of the clamp head 17, these gaps will be covered, so that the clamp 16 has a certain adsorption force.

[0063] The MWD instrument fishing head 13 is locked with a plurality of steel bars. Under the gravity of the MWD instrument, the plurality of steel bars continuously reduce in diameter and firmly lock the MWD instrument body. The change in the flow channel area of ​​the connecting body can then accurately determine whether the fishing instrument enters the clamp 16.

[0064] This embodiment is another preferred implementation method. The overall structural design of the salvaging tool is reasonable, the structure is simple, and the salvaging is convenient.

[0065] Example 4

[0066] See also Figure 1-Figure 12 , based on embodiment 1, 2 or 3, a method for using a MWD naked hole salvage tool is also provided, comprising the above-mentioned MWD naked hole salvage tool;

[0067] S01. Lower the MWD open hole salvage tool to 7-13m before the location of the MWD instrument;

[0068] S02, start the mud pump to circulate and discharge oil and gas, and record the drilling parameters related to hanging weight, lifting friction resistance, lowering friction resistance, rotation resistance, pump stroke and pump pressure;

[0069] S03, then start rotating the drilling tool and lower the MWD open hole fishing tool;

[0070] S04. When the pump pressure rises, continue to rotate and lower the MWD open hole salvage tool by 10-15 cm and observe the change of pump pressure;

[0071] S05. If the pump pressure continues to increase, pull out the MWD open-hole salvage tool;

[0072] S06. If the pump pressure does not change or decreases, repeat steps S03, S04 and S05 in sequence.

[0073] Specifically, the joint tube 9 is connected to the drill bit, and the drill is lowered to 10m before the possible location of the MWD instrument where the object may exist. The mud pump is turned on to circulate and discharge the oil and gas, and the relevant drilling parameters such as the hanging weight, the upward friction resistance, the downward friction resistance, the rotation resistance, the pump stroke, and the pump pressure are recorded at the same time; then the drill bit is rotated at a low speed to lower the salvage tool; when the MWD instrument enters the extension tube 3 through the guide tube, the circulating pump pressure rises significantly, indicating that the object has entered the salvage tool. At this time, the drill bit is continued to be rotated and lowered. If there is no resistance, the lowering depth of the salvage tool is calculated according to the size of the object to be salvaged. When the calculated lowering depth reaches the required After that, continue to lower the drill tool for 10-15cm and observe the change of pump pressure. If the pump pressure continues to increase, it means that the instrument salvage head 13 has completely entered the salvage tool and is locked; slowly lift the drill tool and observe the change of pump pressure. If the pump pressure does not drop, it means that the MWD instrument salvage head 13 is firmly grasped and the drill tool can be continued to be lifted; if the pump pressure drops, it is necessary to repeat the above actions to salvage the MWD instrument again; after the MWD instrument is firmly grasped, continue to lift the drill tool to the wellhead, remove it from the connection between the upper joint of the salvage tool and the drill pipe joint, use the lifting ring and pneumatic winch to take the MWD instrument out of the upper joint, and complete the MWD instrument salvage work.

[0074] This embodiment is the best implementation method. The entire salvage process is simple to operate and easy to perform, which greatly improves the salvage efficiency.

Claims

1. A MWD open-hole salvage tool, characterized by: The invention comprises a guide tube (1), an extension tube (3) and a joint tube (9), wherein one end of the guide tube (1) is connected to one end of the extension tube (3), and the other end of the extension tube (3) is connected to the joint tube (9), wherein a joint device for connecting to a fishing head (13) of an MWD instrument is arranged in the joint tube (9); The connector device comprises a main body (4) and a clamping device, wherein the clamping device is connected to one end of the main body (4) and is used to connect to a fishing head (13) of an MWD instrument; The clamping device comprises two symmetrically arranged slips (10), through grooves (8) adapted to the slips (10) are symmetrically provided on both sides of the main body (4), the slips (10) are located in the through grooves (8) for sliding, and the main body (4) is also provided with a limiting device for limiting the movement of the slips (10); The limiting device is a first spring (11), the top of the slip (10) and the top of the through groove (8) are both arranged in an inclined surface, a first groove (7) is provided in the middle of the main body (4) around the main body (4), a second groove (12) is provided in the middle of the slip (10), and the first spring (11) is arranged in both the first groove (7) and the second groove (12).

2. The MWD open hole salvage tool according to claim 1, characterized in that: The invention also comprises a buffer mechanism, the buffer mechanism comprising a guide rod (5) and a second spring (6), the guide rod (5) being arranged in the joint tube (9) through a connection base, a sliding groove being arranged at the top of the guide rod (5), the main body (4) sliding on the guide rod (5) through the sliding groove, and a second spring (6) being arranged between the bottom of the guide rod (5) and the main body (4).

3. The MWD open hole salvage tool according to claim 1, characterized in that: The joint device also includes a snap-in mechanism (15), which includes a connecting ring (14) and a plurality of steel bars arranged on the connecting ring (14), the steel bars being arranged around the connecting ring (14), and the steel bars being bent inwards to form a grabbing cavity for locking the fishing head (13) of the MWD instrument.

4. The MWD open hole salvage tool according to claim 3, characterized in that: It also comprises a supporting cavity (18) and a clamp head (17), wherein the clamp head (17) is arranged inside the supporting cavity (18), and the spring-clamp mechanism (15) is arranged at the bottom of the clamp head (17).

5. A MWD open hole salvage tool according to claim 4, characterized in that: A clamp (16) is arranged at one end of the clamp head (17) away from the spring clamp mechanism (15), and a plurality of protrusions are arranged on the inner surface of the clamp (16).

6. The MWD open hole salvage tool according to claim 1, characterized in that: The tails of the guide tube (1) and the extension tube (3) are both provided with a straightening seat (2).

7. A method for using an MWD naked-hole salvage tool, characterized in that: Using the MWD open hole salvage tool as claimed in claim 1, comprising the following steps: S01. Lower the MWD open hole salvage tool to 7-13m before the location of the MWD instrument; S02, start the mud pump to circulate and discharge oil and gas, and record the drilling parameters related to hanging weight, lifting friction resistance, lowering friction resistance, rotation resistance, pump stroke and pump pressure; S03, then start rotating the drilling tool and lower the MWD open hole fishing tool; S04. When the pump pressure rises, continue to rotate and lower the MWD open hole salvage tool by 10-15 cm and observe the change of pump pressure; S05. If the pump pressure continues to increase, pull out the MWD open-hole salvage tool; S06. If the pump pressure does not change or decreases, repeat steps S03, S04 and S05 in sequence.

Images