Downhole fallen object fishing device
By combining the magnetic salvage device with a sand sinking cylinder, the problem of low salvage success rate of small and medium-sized iron drops is solved in the prior art, efficient and safe recovery of iron drops is achieved, and construction efficiency and safety are improved.
Patent Information
- Application Number
- CN202422046249.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-22
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-08-22
AI Technical Summary
The existing underground salvage device has a low success rate when dealing with small iron items, which can easily cause salvage failure or increase construction risks.
A well falling object salvage device is designed, combining a magnetic salvager and a sand sinking cylinder, and recovering the fall object through magnetic adsorption and annular space. The fall object is suspended and entered the inner cavity of the sand sinking cylinder with flushing liquid. It is combined with the magnetic separator and chamfer design to avoid accumulation and improve the salvage success rate.
The salvage success rate of small iron drops has been improved from 70% to more than 96%, reducing construction risks and costs, and ensuring the safety and efficiency of construction.
Smart Images
Figure CN223062407U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a downhole fallen object salvaging device, belonging to the technical field of downhole operation tools for oil field development. Background Art
[0002] During the underground operation overhaul construction, the unstuck salvage, grinding, and milling processes will produce irregular iron debris in the form of wire strips and blocks. The iron debris sinks to the top of the fish. If it is not handled cleanly and salvaged blindly, it will cause salvage failure, or after the fish is salvaged, it will cause a drill jam, which will bring difficulties to the next step of construction and increase construction risks.
[0003] At present, there are two main processing methods for salvaging small iron objects at home and abroad:
[0004] 1. Use a strong magnetic salvage device for salvage: 1) As the depth of treatment increases, the magnetic field strength is significantly weakened by the temperature downhole, and only some small iron filings can be adsorbed. 2) There is a hard cover layer formed by rock particles or sediments on the top of the iron fish. The water eye of the magnetic salvage device has weak sprinting ability and cannot disperse the cover layer. It cannot contact the iron objects and cause salvage failure. 3) During the drilling process, the magnetic lines of the magnetic salvage device contact the inner wall of the casing with the iron objects, the magnetic field weakens, and the shaking of the pipe string or unstable operation will cause the iron objects to fall into the well again, which will result in a low salvage success rate.
[0005] 2. Use a pen tip with a sand settling tube to flush the fish top. The impact force can flush the debris on the surface of the fish top into a suspended state, and return to the drill pipe body on the upper part of the sand settling tube with the upward movement of the liquid. The annular space becomes larger and the flow rate decreases. The iron debris automatically sinks and is recovered by the sand settling tube cavity and brought out to the ground. The disadvantage is that due to the large flushing area of the pen tip, the effect of flushing the surface of the fish top is good, but the impact forces in the central area offset each other, affecting the flushing of iron debris deep in the tool cavity. Practice has proved that the success rate of debris recovery by the sedimentation cup is about 60-70%, and the remaining 30-40% of the debris falls back into the fish top or annulus, causing hidden dangers for the next construction and increasing construction costs and procedures. Utility Model Content
[0006] The utility model aims to provide a downhole fallen object salvaging device, which is used to solve the problem that the existing salvaging device has a low success rate in salvaging small iron fallen objects.
[0007] To achieve the above purpose, the solution of the utility model includes:
[0008] A downhole fish salvage device of the utility model includes a drill pipe short joint. One end of the drill pipe short joint is used for detachably connecting a wash pipe, a mill shoe or a milling barrel, and the other end is used for detachably connecting a drill tool. A sand settling cylinder is sleeved on the outer side wall of the drill pipe short joint. One end of the sand settling cylinder close to the drill pipe short joint is connected to the drill pipe short joint so as to form an annular space communicating with the outside of the sand settling cylinder between the sand settling cylinder and the drill pipe short joint. The opening of the annular space communicating with the outside of the sand settling cylinder faces the other end of the drill pipe short joint. A magnetic fish finder is sleeved on the drill pipe short joint on the opening side. Water filtering holes are formed in the barrel body of the sand settling cylinder far away from the opening.
[0009] The downhole fish salvage device of the utility model adsorbs iron fish by the magnetic fish finder, and also recovers fish through the annular space between the sand settling cylinder and the drill pipe short joint. The use of the two in cooperation improves the salvage success rate of the salvage device. When salvaging with the utility model, the washing fluid passes through the inner cavity of the drill pipe short joint from the other end of the drill pipe short joint used for detachably connecting the drill tool, and then flushes the fish to be salvaged through one end of the drill pipe short joint used for detachably connecting the wash pipe or the wash pipe. The impact force during flushing disperses the fish into a suspended state and makes it approach the other end of the drill pipe short joint, so that the fish enters the inner cavity of the sand settling cylinder from the opening of the annular space, the liquid flows out through the water filtering holes, and the fish automatically falls back into the inner cavity of the sand settling cylinder. The fish that can be magnetically adsorbed (such as iron fish) is adsorbed by the magnetic fish finder, which improves the success rate of fish salvage. The utility model is used with a mill shoe, a milling barrel or a wash pipe according to different processes, and uses the characteristics of the combination of tools for flushing, cleaning and collecting to ensure the maximum recovery of small ferromagnetic fish.
[0010] Further, magnetic isolation sleeves are arranged at both ends of the magnetic fish finder, and the outer end faces of the two magnetic isolation sleeves are chamfered to prevent fish from accumulating at both ends of the magnetic fish finder.
[0011] The utility model arranges magnetic isolation sleeves at both ends of the magnetic fish finder to prevent the small iron fish adsorbed by it from accumulating at both ends of the magnetic fish finder and blocking the opening of the annular space communicating with the outside of the sand settling cylinder. The utility model chamfers the outer end faces of the magnetic isolation sleeves outwards to prevent fish from accumulating at both ends of the magnetic fish finder, neither being adsorbed nor falling into the annular space (the inner cavity of the sand settling cylinder). When taking out the salvage device, the fish accumulated at both ends of the magnetic fish finder are extremely easy to fall off, reducing the salvage success rate.
[0012] Further, the magnetic fish finder includes magnets with like poles facing each other, and a magnetic isolation pad is arranged between adjacent two magnets to keep the magnetic lines of force radially distributed around the magnets.
[0013] The magnetic fish finder of the utility model is composed of magnets with like poles facing each other, and a magnetic isolation pad is arranged between adjacent two magnets to keep the magnetic lines of force of the magnetic fish finder radially distributed around the magnetic fish finder. The magnetic isolation pad is used to eliminate the repulsive force between like poles of the magnets.
[0014] Furthermore, the end face of the sand settling cylinder at the opening position is chamfered both inside and outside.
[0015] The end face of the sand settling cylinder at the opening position of the present utility model is chamfered both inside and outside. The inner chamfer can be a 30° chamfer, which is used to guide iron objects to smoothly slide into the cup-shaped barrel of the opening; the outer chamfer can be a 45° chamfer, which is used to prevent small iron objects from bridging between the drill pipe body and the cup mouth of the barrel, prevent object accumulation from causing stuck drilling, and improve the success rate of fishing for dropped objects.
[0016] Furthermore, a centralizer is provided between the end of the sand settling cylinder close to the opening and the short drill pipe section.
[0017] The sand settling cylinder of the present utility model is supported and fixed by a centralizer between the short drill pipe section to prevent the sand settling cylinder from swinging during rotation, resulting in unstable opening size of the annular space and reducing the success rate of fishing for dropped objects.
[0018] Furthermore, one end of the short drill pipe section is provided with an internal thread for screwing with the wash pipe and an external thread for screwing with the mill shoe or the milling barrel.
[0019] The short drill pipe section of the present utility model is detachably screwed with the wash pipe, the mill shoe, and the milling barrel respectively, which is convenient for replacement, installation, and disassembly.
[0020] Furthermore, the diameter of the water filtering holes is 10 mm.
[0021] The size of the water filtering holes opened on the barrel body of the sand settling cylinder of the present utility model is determined according to the size of the fishing object, which can ensure that the dropped object will not leave through the water filtering holes while not blocking the water filtering holes, and ensure the success rate of the fishing device.
[0022] Furthermore, the connection between the end of the sand settling cylinder close to the short drill pipe section and the short drill pipe section is detachable.
[0023] One end of the sand settling cylinder of the present utility model is detachably sleeved on the outer side wall of the short drill pipe section. One end of the sand settling cylinder is the end close to the short drill pipe section used for detachably connecting the wash pipe or the mill shoe or the milling barrel, which is convenient for disassembling the sand settling cylinder and cleaning the inner cavity of the sand settling cylinder.
[0024] Furthermore, the end of the sand settling cylinder close to the short drill pipe section is screwed with the outer side wall of the short drill pipe section, and the thread direction of the sand settling cylinder is opposite to the working direction of the drill tool to avoid the sand settling cylinder from disengaging from the short drill pipe section.
[0025] One end of the sand settling cylinder of the present utility model is screwed and sleeved on the outer side wall of the short drill pipe section, and the thread direction of the sand settling cylinder is opposite to the working direction of the drill tool to avoid the sand settling cylinder from disengaging from the short drill pipe section, causing construction accidents, and improving the safety performance of the fishing device.
[0026] Furthermore, the end of the wash pipe far from the connection with the short drill pipe section is a bevel cut.
[0027] One end of the flushing pipe of the present utility model, which is far from the end connected to the drill pipe short joint, is an inclined cut, that is, the front end of the flushing pipe is an inclined cut, and the shape of the inclined cut is a nib shape, which can pierce the hard cover layer of the fish top, avoiding the failure of fishing due to the hard cover layer formed by rock particles or sediment on the upper part of the iron fish top, resulting in the inability to contact the iron dropped object. Description of the Drawings
[0028] Figure 1 is a schematic structural diagram of the fishing device of the present utility model;
[0029] Figure 2 is a schematic dimension diagram of the fishing device of the present utility model.
[0030] Description of the Reference Numerals in the Drawings:
[0031] 1. Flushing pipe; 101. Inclined cut; 102. Liquid flow channel; 103. First thread; 2. Under-reaming cup; 201. Second thread; 202. Third thread; 203. Water filtering eye; 204. Sand settling cylinder; 205. Centralizer; 206. Drill pipe short joint; 207. Upper sub; 3. Magnetic fishing tool; 301. Magnetic isolation pad; 302. Magnet; 303. Magnetic isolation sleeve. Detailed Embodiment
[0032] To make the purpose, technical solution and advantages of the present utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the drawings and embodiments.
[0033] An embodiment of a downhole dropped object fishing device:
[0034] To solve the problem that the success rate of the existing fishing device for fishing small iron dropped objects is low, that is, the recovery efficiency of small iron dropped objects is low, a special tool integrating flushing, recovery and magnetization adsorption functions is designed to maximize the recovery of small iron dropped objects.
[0035] A downhole dropped object fishing device, as Figure 1 shown, the present utility model mainly consists of a flushing pipe 1, an under-reaming cup (under-reaming fishing cup) 2 and a magnetic fishing tool 3.
[0036] The front end of the flushing pipe 1 is an inclined cut 101 in the shape of a nib, which can be used to pierce the hard cover layer of the fish top; the inside of the flushing pipe 1 is hollow to form a liquid flow channel 102; the end of the flushing pipe, that is, the first thread 103 (external thread) at the tail of the flushing pipe, is screwed to one end of the drill pipe short joint 206, that is, the first thread 103 is screwed to the internal thread at one end of the drill pipe short joint 206, and the flushing pipe 1 is used in combination with the internal thread connection of the under-reaming cup 2.
[0037] The front end of the fishing cup while drilling 2 (the front end of the fishing cup while drilling is one end of the drill pipe nipple) is the second thread 201 (external thread) of the lower sub, which is connected (screwed) to the mill shoe or the overshot. The mill shoe is used for milling iron debris, and the overshot is used for overmilling iron debris in the annular space. The internal thread at the front end of the fishing cup while drilling 2 can also be connected to the first thread 103 on the swivel pipe to directly wash the fish top that does not require milling and overmilling.
[0038] The body of the sand settling cylinder 204 is provided with water filtering holes 203, and the water filtering holes 203 are round holes with a diameter of φ10mm. The sand settling cylinder 204 is connected to the lower sub of the drill pipe nipple 206 by the third thread 202. The thread direction of the third thread 202 is opposite to the working direction of the downhole drill string to prevent the sand settling cylinder from loosening and disconnecting from the drill pipe nipple, causing construction accidents. An annular space communicating with the outside of the sand settling cylinder is formed between the sand settling cylinder and the drill pipe nipple. The opening of the annular space communicating with the outside of the sand settling cylinder faces the drill string. The sand settling cylinder 204 and the drill pipe nipple 206 are supported and fixed by a centralizer 205 to prevent the sand settling cylinder from swinging during rotation. The upper end face of the sand settling cylinder 204 is chamfered both inside and outside, that is, the end face of the sand settling cylinder 204 at the opening position is chamfered both inside and outside. The internal chamfer is a 30° chamfer, which is used to guide iron objects to smoothly slide into the cup body. The external chamfer is a 45° chamfer, which is used to prevent small iron objects from bridging between the drill pipe body and the cup body of the cylinder, preventing object accumulation and causing sticking of the drill string. A magnetic fishing tool is sleeved on the drill pipe nipple on the opening side, that is, the drill pipe nipple body is sleeved into the magnetic fishing tool 3 and fixed. The upper sub 207 of the drill pipe nipple 206 connects the present utility model to the downhole drill string.
[0039] For the magnetic fishing tool 3, a circular neodymium iron boron magnet 302 with good stability, high temperature resistance, and not easily demagnetized is selected as the material. A circular stainless steel is sleeved between the magnets 302 as a magnetic isolation pad 301. The magnetic isolation pad is used to eliminate the repulsive force between the same magnetic poles of the magnets, keeping the magnetic lines of force radially distributed around the annular magnet. The two ends of the magnetic fishing tool are magnetic isolation sleeves 303, and the upper and lower end faces are both chamfered at 45°, that is, the outer end faces of the two magnetic isolation sleeves 303 are both chamfered at 45° to prevent debris accumulation.
[0040] The washing fluid flushes the fish through the swivel pipe 1. The impact force flushes the small iron fish into a suspended state and makes them move upward. The iron debris enters the inner cavity of the sand settling cylinder from the opening position, and the liquid flows out through the water filtering holes 203. The small iron objects automatically fall back, are magnetically adsorbed, and fall into the inner cavity of the sand settling cylinder, improving the fishing success rate.
[0041] See Figure 1, when using the present utility model for construction, after optimization, the inner diameter and wall thickness of the flushing pipe 1 are increased, the flow velocity resistance is reduced, and the reliability and safety of the tool are improved; after optimization, the outer shape of the sand settling cylinder 204 is φ114mm×φ100mm×0.65m, the length of the sand settling cylinder is shortened, the annular space of the short joint distance is increased, the high-speed liquid flow enters the annular space of the drill pipe body and descends slowly, and small iron objects automatically fall back, pass through magnetic adsorption and fall into the inner cavity of the sand settling cylinder, improving the fishing success rate; the magnetic fishing tool 3 selects annular neodymium iron boron magnets, which have the advantages of high temperature resistance, the highest working temperature reaching 200°C, and strong magnetism; rare elements are added, and the texture is hard; the surface is treated with nickel, zinc, and tin electroplating for anti-corrosion, and the performance is stable; an austenitic stainless steel is sleeved between every two magnets as a magnetic isolation sleeve or magnetic isolation pad to eliminate the repulsive force between the magnets, and a ring-shaped low-alloy steel material with a chamfer is installed on the outer side of the spacer ring at both ends of the magnet, and the magnet is fixed on the drill pipe body by welding; the controlled magnetic lines are radially concentrated and gathered in the side direction of the magnet to adsorb the small ferromagnetic falling objects that fall back, improving the fishing success rate. Figure 2 is a dimensional schematic diagram of the fishing device of the present utility model, with the unit of millimeters.
[0042] Considering the comprehensive application characteristics, a strong magnetic fishing device is installed below the coupling at the body part of the upper drill pipe (drill pipe short joint) of the fishing cup while drilling. According to different processes, it is used with a mill bit, a milling barrel or a flushing pipe, and the characteristics of the combination of tools are used for flushing, cleaning and collecting to ensure the maximum fishing of small ferromagnetic falling objects. Through one-year on-site application, it shows that a downhole falling object (small iron) fishing device is convenient to process, reliable in performance, simple in fishing operation, and meets the process and safety requirements; it effectively solves the difficulty of low fishing success rate of small iron falling objects, improves the original fishing efficiency from 70% to over 96%, has good popularization and application value, and lays a solid foundation for finally forming a product.
Claims
1. A downhole fishing device, characterized in that, It includes a drill pipe sub. One end of the drill pipe sub is used for detachably connecting a wash pipe, a mill shoe or a junk mill, and the other end is used for detachably connecting a drill string. A sand settling cylinder is sleeved on the outer side wall of the drill pipe sub. One end of the sand settling cylinder close to the drill pipe sub is connected to the drill pipe sub so as to form an annular space communicating with the outside of the sand settling cylinder between the sand settling cylinder and the drill pipe sub. The opening of the annular space communicating with the outside of the sand settling cylinder faces the other end of the drill pipe sub. A magnetic fishing tool is sleeved on the drill pipe sub on the opening side. Filter water holes are formed in the cylinder body of the sand settling cylinder far away from the opening.
2. The downhole fish fishing device according to claim 1, wherein, Magnetic isolation sleeves are arranged at both ends of the magnetic fishing tool. The outer end faces of the two magnetic isolation sleeves are chamfered to prevent debris from accumulating at both ends of the magnetic fishing tool.
3. The downhole fishing tool according to claim 1 or 2, characterized in that, The magnetic fishing tool includes magnets with like poles facing each other. A magnetic isolation pad is arranged between adjacent two magnets to keep the magnetic lines of force radially distributed around the magnets.
4. The downhole fishing tool according to claim 1, wherein The end face of the sand settling cylinder at the opening position is chamfered both inside and outside.
5. The downhole fishing device according to claim 1, characterized in that, A centralizer is arranged between one end of the sand settling cylinder close to the opening and the drill pipe sub.
6. The downhole fishing tool according to claim 1, wherein, One end of the drill pipe sub is provided with an internal thread for screwing with a wash pipe and an external thread for screwing with a mill shoe or a junk mill.
7. The downhole fish fishing device according to claim 1, characterized in that, The diameter of the filter water holes is 10 millimeters.
8. The downhole fishing device according to claim 1, characterized in that, The connection between one end of the sand settling cylinder close to the drill pipe sub and the drill pipe sub is detachable.
9. The downhole fishing device according to claim 8, wherein, One end of the sand settling cylinder close to the drill pipe sub is screwed to the outer side wall of the drill pipe sub. The thread direction of the sand settling cylinder is opposite to the working direction of the drill string to avoid the sand settling cylinder coming off from the drill pipe sub.
10. The downhole fishing device according to claim 1, characterized in that, One end of the wash pipe far away from the connection with the drill pipe sub is an inclined cut.