Internal and external double-slip composite fishing tool and downhole fish fishing method

Abstract

The invention provides an inner and outer double-slip composite fishing tool and a downhole fish fishing method, the fishing tool comprises a back-off fishing spear, a fishing barrel and an anti-expansion sleeve, the fishing barrel is arranged outside the back-off fishing spear, the anti-expansion sleeve and the lower end of the fishing barrel are connected and have the same diameter, the inner wall of the fishing barrel is provided with slip inserts, and the lower part of the fishing barrel is provided with a limiting structure; the lower end of the back-off fishing spear is connected with a returnable fishing spear, and a round slip is arranged on the returnable fishing spear. Through the combination of the back-off fishing spear, the fishing barrel and the returnable fishing spear, triple internal and external fishing is carried out on a fish, the fishing area is increased, and the situation that the fish is broken and falls off due to the stress concentration phenomenon on a fishing point after the fish with the corrosion strength reduced is grabbed is avoided; and meanwhile, the anti-expansion sleeve can limit the fallen fish to prevent the fallen fish from being broken due to strength reduction, so that successful fishing is further ensured. According to the internal and external double-slip combined fishing tool, full-size fishing of an oil pipe body, an enlarged part and a coupling of a fish head can be achieved, and the one-time fishing success rate can be increased by using the internal and external double-slip combined fishing tool.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas well production, and in particular relates to an inner and outer double slip composite fishing tool and a method for fishing fish in a well. Background Art

[0002] At present, there are only separate 73mm diameter tubing bodies, enlarged parts, and coupling salvage spears (tubes) at home and abroad. Each tool can only salvage fish of a single size, or fish with relatively standardized fish tops and unchanged diameters. In fact, most water wells, coalbed methane wells, and gas wells have broken tubing due to long production time, corrosion from hydrogen sulfide gas, sewage, chemicals (acids) and additives entering the well, and most tubing can no longer withstand the tensile stress and torsional stress caused by rotation when clamped and caught by separate kava teeth. Conventional separate internal and external salvage tools can no longer be used. When using a mother cone for salvage, the tubing has low strength and can only salvage a small section, making salvage more complicated. The salvage of 73mm diameter tubing in horizontal wells has the problem of difficulty in entering the fish with salvage tools and difficulty in catching with kava teeth.

[0003] The patent number is CN113431516A, and the patent name is "A downhole fish salvage assembly and salvage method". The disclosed salvage assembly includes a jar and a salvage piece. The jar includes a connecting cavity arranged at one end and a connecting head arranged at the other end; a slider that can slide in the connecting cavity is arranged in the connecting cavity; the connecting head is used to connect with a lifting device to realize the lifting and lowering of the jar; a detector, the detector includes a detection head arranged at one end and a first connecting part arranged at the other end; the salvage piece includes a salvage head arranged at one end and a second connecting part arranged at the other end; one end of the slider is located in the connecting cavity, and the other end of the slider can be detachably connected to the first connecting part or the second connecting part respectively. Through improvement, the purpose of improving the success rate of downhole fish salvage can be achieved, and the on-site construction work can be carried out smoothly. However, the size of the fish salvaged by the salvage device is single, and the salvage piece needs to be replaced to realize the salvage of fish of different specifications. Moreover, when the strength of the fish decreases due to corrosion, the fish will be broken during the salvage process, thereby failing to salvage. Summary of the invention

[0004] The purpose of the present invention is to provide an inner and outer double slip composite fishing tool to overcome the above-mentioned technical problems existing in the prior art.

[0005] Another object of the present invention is to provide a method for salvaging fish in a well, which realizes the full-size salvage of the tubing joint and the tubing body, and has a wider range of applications.

[0006] To this end, the technical solution provided by the present invention is as follows: A composite salvaging tool with inner and outer double slips comprises an inverted salvaging spear, a salvaging tube and an anti-expansion sleeve, wherein the salvaging tube is arranged outside the inverted salvaging spear, the anti-expansion sleeve is connected to the lower end of the salvaging tube and the two have the same diameter, the inner wall of the salvaging tube is provided with slip teeth, the lower part of the salvaging tube is provided with a limiting structure, the lower end of the inverted salvaging spear is connected to a retractable salvaging spear, and the retractable salvaging spear is provided with a round slip.

[0007] The inverted bailing spear comprises an upper joint, an expansion sleeve and an expansion core shaft which are sequentially connected from top to bottom, and the upper joint is threadedly connected to the bailing tube.

[0008] The retractable spear comprises a spear core shaft, a round slip and a guide cone. The spear core shaft is fixedly connected to the expansion core shaft. The spear core shaft is provided with a sawtooth thread. The round slip is arranged on the spear core shaft and the round slip teeth match the sawtooth thread. The guide cone is arranged at the bottom end of the spear core shaft.

[0009] The diameter of the circular slip is larger than the diameter of the lance core shaft.

[0010] A method for salvaging fish in a well uses a salvage pipe string, which comprises an inner and outer double-slip composite salvage tool, a salvage cup, a drill collar 5 column, a salvage cup and a drill pipe connected in sequence from bottom to top. During salvage, the fish in the well first enters the salvage tool under the guidance of an anti-expansion sleeve, and then a guide cone enters the fish. The fish compresses the round slip, and the salvage pipe string is lifted up. The round slip teeth match the serrated threads on the spear core shaft to generate radial force, thereby biting the inner diameter of the fish to achieve salvage.

[0011] When the strength of the fallen fish decreases due to corrosion, during the salvage process, the anti-expansion sleeve restricts the circumference of the fallen fish to prevent the fallen fish from being burst, thereby achieving salvage.

[0012] When the fish is an oil pipe with a segmented hoop, the fish compresses the round slip and continues to move upward but is restricted by the limit structure at the bottom of the bailing tube. At this time, the tool is lifted, and the round slip teeth on the retractable bailing spear match the serrated threads on the bailing spear core shaft to generate radial force, thereby biting the inner diameter of the fish and achieving salvage.

[0013] When the fallen fish is the oil pipe body, the fallen fish compresses the round slip and moves up to pass through the slip teeth of the salvage tube until it is blocked by the limit at the upper joint. At this time, the salvage tool is lifted up, and the expansion sleeve moves down along the expansion core shaft to increase its outer diameter. The expansion sleeve bites the inner diameter of the oil pipe under the action of the radial force, and at the same time, the slip teeth of the salvage tube bite the outer diameter of the oil pipe under the action of the radial force of the inclined surface of the inner wall of the salvage tube. The round slip of the retractable salvaging spear at the lowest part of the tool also grabs the oil pipe from the inner wall of the fish falling oil pipe, and the three groups of slip teeth work together to grab the oil pipe inside and outside to achieve salvage.

[0014] The beneficial effects of the present invention are: The composite salvaging tool with internal and external double slips provided by the present invention performs triple internal and external catching of fallen fish by combining an inverted catching spear, a catching tube and a retractable catching spear, thereby increasing the salvaging area and preventing the fallen fish from being caught due to corrosion and reduced strength and causing stress concentration at the catching point and breaking off; at the same time, the anti-expansion sleeve can limit the fallen fish to prevent it from being burst due to reduced strength, thereby further ensuring successful salvage.

[0015] The invention is suitable for salvaging various fish heads under severe corrosion, and can also solve the problem of full-size salvaging of the fish head, which is the oil pipe body, the enlarged part, and the coupling. The use of the internal and external double slip combined salvage tool can improve the success rate of salvaging once. It also reduces the printing process for judging the fish head, speeds up the construction efficiency, and reduces the labor intensity of employees in the frequent operation process.

[0016] In field applications, the tool has a high salvage success rate, especially in the salvage of severely corroded oil pipes. One salvage can complete the work of several previous times, and the salvage success rate is high. This shows that the construction efficiency is improved by 200%, the success rate is increased by 100%, and the economic benefits are increased several times. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of an implementation method of the present invention.

[0018] In the figure: 1. Inverted spear; 2. Lifting tube; 3. Retractable spear; 4. Anti-expansion sleeve; 5. Upper joint; 6. Expansion sleeve; 7. Expansion mandrel; 8. Slip teeth; 9. Spear mandrel; 10. Round slip; 11. Guide cone. Implementation

[0019] The following describes the implementation of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0020] The exemplary embodiments of the present invention are now described with reference to the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely and to fully convey the scope of the present invention to those skilled in the art. The terms used in the exemplary embodiments shown in the accompanying drawings are not intended to limit the present invention. In the accompanying drawings, the same units / elements are marked with the same reference numerals.

[0021] Unless otherwise specified, the terms (including technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is understood that the terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings. Example

[0022] This embodiment provides a composite fishing tool with inner and outer double slips, such as Figure 1 As shown, it includes an inverted bailing spear 1, a bailing tube 2 and an anti-expansion sleeve 4, the bailing tube 2 is arranged outside the inverted bailing spear 1, the anti-expansion sleeve 4 is connected to the lower end of the bailing tube 2 and the two have the same diameter, the inner wall of the bailing tube 2 is provided with a slip tooth 8, the lower part of the bailing tube 2 is provided with a limiting structure, the lower end of the inverted bailing spear 1 is connected with a retractable bailing spear 3, and the retractable bailing spear 3 is provided with a round slip 10.

[0023] Working principle of the present invention: During salvage, the fish in the well first enters the salvage tool under the guidance of the anti-expansion sleeve 4, and then the guide cone 11 enters the fish, and the fish moves up along the retractable salvage spear 3. When salvaging the oil pipe with a joint hoop, due to the large diameter of the joint hoop, a limit will be formed when entering the bottom of the salvage tube 2, and only the retractable salvage spear 3 can be used for initial salvage; when the oil pipe body without a joint hoop enters the tool, the oil pipe can pass through the salvage tube 2 and directly enter the inverted joint position to form a secondary salvage. At the same time, the slip teeth 8 will also form a grip, so that the tool can grip the oil pipe more firmly, thus forming an internal and external double slip combined salvage.

[0024] The composite salvaging tool with inner and outer double slips provided by the present invention performs triple inner and outer catching of fallen fish by combining the inverted catching spear 1, the catching tube 2 and the retractable catching spear 3, thereby increasing the salvaging area and preventing the fallen fish with reduced strength due to corrosion from being broken off due to stress concentration at the catching point after being caught; at the same time, the anti-expansion sleeve 4 can limit the fallen fish to prevent it from being burst due to reduced strength, thereby further ensuring successful salvage. Example

[0025] Based on Example 1, this embodiment provides an inner and outer double slip composite salvage tool, wherein the inverted salvage spear 1 comprises an upper joint 5, an expansion sleeve 6 and an expansion core shaft 7 connected in sequence from top to bottom, and the upper joint 5 is threadedly connected to the salvage tube 2.

[0026] During salvaging, after the fish is introduced into the tool, it will continue to pass through the cava teeth 8 of the salvage tube 2 and be introduced into the inverted salvage spear 1. The fish head passes through the expansion core shaft 7, squeezes the expansion sleeve 6 and enters the inner diameter of the fish until it reaches the upper joint 5 and is blocked by the limit. At this time, the salvage tool is lifted up, and the expansion sleeve 6 moves down along the expansion core shaft 7 to increase its outer diameter. The expansion sleeve 6 bites the inner diameter of the fish under the action of radial force. Example

[0027] On the basis of Example 2, this embodiment provides an inner and outer double slip composite salvage tool, the retractable spear 3 includes a spear core shaft 9, a round slip 10 and a guide cone 11, the spear core shaft 9 is fixedly connected to the expansion core shaft 7, the spear core shaft 9 is provided with a serrated thread, the round slip 10 is arranged on the spear core shaft 9 and the round slip 10 teeth match the serrated thread, and the guide cone 11 is arranged at the bottom end of the spear core shaft 9.

[0028] The diameter of the round slip 10 is greater than the diameter of the lance core shaft 9 .

[0029] During salvage, the fish in the well first enters the salvage tool under the guidance of the anti-expansion sleeve 4, and then the guide cone 11 enters the fish. The fish moves up along the retractable spear 3, compressing the round slip 10. The teeth of the round slip 10 coincide with the serrated threads on the spear core shaft 9 to generate radial force, thereby biting the inner diameter of the fish to achieve salvage. Example

[0030] On the basis of Example 1, this example provides an inner and outer double slip composite salvage tool, specifically, an inner and outer double slip composite salvage tool for a 73 mm oil pipe.

[0031] like Figure 1 As shown, a core shaft is extended on the expansion core shaft 7 of the inverted spear 1 to form an extension rod, and then the extension rod is processed into a spear core shaft 9 of the retractable spear 3, a round slip 10, a release ring, and a guide cone 11 are installed on the spear core shaft 9 to form the retractable spear 3, a thread is processed on the upper joint 5 of the inverted spear 1, a bailing tube 2 is assembled on the upper joint 5 of the inverted spear 1, and then a guide shoe with the same outer diameter is installed on the bailing tube 2 to form an anti-expansion sleeve 4; a limiting structure is provided at the lower part of the bailing tube 2.

[0032] In this way, when salvaging a 73mm oil pipe with a joint hoop, due to the larger diameter of the joint hoop, a limit will be formed when entering the bottom of the bail 2, and only the retractable bail spear 3 can be used for initial salvage; when the 73mm oil pipe body without a joint hoop enters the tool, the oil pipe can pass through the bail 22 and directly enter the inverted joint position to form a secondary salvage. At the same time, the bail 2 Bluetooth will also form a grabbing function, so that the tool can grab the 73mm oil pipe more firmly, thus forming an internal and external double slip combined salvage. Example

[0033] The present embodiment provides a method for salvaging fish in a well, using a salvage pipe string, which includes an inner and outer double slip composite salvage tool, a salvage cup, a drill collar 5 column, a salvage cup and a drill pipe connected in sequence from bottom to top. During salvage, the fish in the well first enters the salvage tool under the guidance of the anti-expansion sleeve 4, and then the guide cone 11 enters the fish. The fish compresses the round slip 10, and the salvage pipe string is lifted. The teeth of the round slip 10 match the serrated threads on the spear core shaft 9 to generate radial force, thereby biting the inner diameter of the fish to achieve salvage.

[0034] The method of the present invention can at least realize the initial catching of fallen fish by using the retractable catching spear 3. Example

[0035] On the basis of Example 5, this embodiment provides a method for salvaging fish in a well. When the strength of the fish decreases due to corrosion, during the salvaging process, the anti-expansion sleeve 4 restricts the circumference of the fish to prevent the fish from being burst, thereby achieving salvage.

[0036] When the fish is an oil pipe with a segmented hoop, the fish compresses the round slip 10 and continues to move upward, but is restricted by the limit structure at the bottom of the bailing tube 2. At this time, the tool is lifted, and the round slip 10 teeth on the retractable bailing spear 3 coincide with the serrated threads on the bailing spear core shaft 9 to generate radial force, thereby biting the inner diameter of the fish to achieve salvage.

[0037] When the fallen fish is the oil pipe body, the round slip 10 is compressed by the fallen fish and moves up to pass through the slip teeth 8 of the salvage tube 2 until it is blocked by the limit position at the upper joint 5. At this time, the salvage tool is lifted up, and the expansion sleeve 6 moves down along the expansion core shaft 7 to increase its outer diameter. The expansion sleeve 6 bites the inner diameter of the oil pipe under the action of the radial force. At the same time, the slip teeth 8 of the salvage tube 2 bite the outer diameter of the oil pipe under the action of the radial force of the inclined surface of the inner wall of the salvage tube 2. The round slip 10 of the retractable salvaging spear 3 at the lowest part of the tool also grabs the oil pipe from the inner wall of the oil pipe where the fish is fallen. The three groups of slip teeth 8 work together to grab the oil pipe inside and outside to achieve salvage.

[0038] This embodiment takes the salvaging of a 73 mm oil pipe body and an oil pipe joint as an example to further illustrate the present invention.

[0039] The outer diameter of the round slips 10 teeth in the free state is slightly larger than the inner diameter of the 73mm oil pipe. During salvage, the anti-expansion sleeve 4 is first introduced into the tool, and then the guide cone 11 is introduced into the tool. At this time, the round slips 10 are compressed and enter the inner diameter of the 73mm oil pipe. If the oil pipe with objects in the well is equipped with a section hoop, the section hoop is blocked by the lower limit of the blue type bucket 2 and cannot enter the blue type bucket 2. The salvage pipe string is lifted up, and the round slips 10 teeth on the retractable fishing spear 3 are matched with the serrated threads on the fishing spear core shaft 9 to generate radial force, so that ... The inner diameter of the 115mm anti-expansion sleeve 4 is 97mm, the outer diameter of the 73mm oil pipe joint is 90mm, and the salvage range of the round slip 10 is above 77mm. In this way, it can be ensured that when the oil pipe decreases due to corrosion strength, it will not be burst under the protection of the anti-expansion sleeve 4 and can be successfully salvaged.

[0040] If the fish top of the fish falling downhole is a 73mm tubing body, after the falling object is introduced into the tool, it will continue to pass through the slip teeth 8 of the fishing tube 2 and be introduced into the inverted fishing spear 1. The fish head of the 73mm tubing body passes through the expansion core shaft 7, squeezes the expansion sleeve 6 and enters the inner diameter of the 73mm tubing, and reaches the upper joint 5 and is blocked by the limit. At this time, the fishing string is lifted up, and the expansion sleeve 6 moves down along the expansion core shaft 7 to increase its outer diameter. The expansion sleeve 6 bites the inner diameter of the 73mm tubing under the action of the radial force, and at the same time, the slip teeth 8 of the fishing tube 2 bite the outer diameter of the 73mm tubing under the action of the radial force of the inner wall inclined surface of the fishing tube 2; the round slips 10 of the retractable fishing spear 3 at the lowest part of the tool also grab the tubing from the inner wall of the fish falling tubing, so that the three groups of slip teeth 8 work together to grab the tubing inside and outside, no matter how corroded the tubing is, it can be captured firmly to ensure the salvage effect.

[0041] In summary, since the strength of the corroded oil pipe is low, if you want to fish out the oil pipe every time, you must increase the fishing area. Only when the fishing area is increased and the oil pipe with reduced corrosion strength is fished out, stress concentration will not form at the fishing point and break off. In addition, while the inverted fishing spear 1 and the fishing tube 2 are double fishing inside and outside, the retractable fishing spear 3 also fishes the 73mm oil pipe inner diameter, so that the three-fold inside and outside fishing of the inverted fishing spear 1, the fishing tube 2 and the retractable fishing spear 3 are simultaneously realized within the range of 1.5m of the tool: inside fishing, outside fishing, and outside fishing. This solves the fishing problem of the corroded oil pipe with irregular top, difficulty in fishing, and low strength and easy to break.

[0042] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. All designs that are the same or similar to the present invention fall within the protection scope of the present invention.

Claims

1. A composite fishing tool with inner and outer double slips. Features: The utility model comprises an inverted bailing spear, a bailing tube and an anti-expansion sleeve, wherein the bailing tube is arranged outside the inverted bailing spear, the anti-expansion sleeve is connected to the lower end of the bailing tube and the two have the same diameter, a slip tooth is arranged on the inner wall of the bailing tube, a limiting structure is arranged at the lower part of the bailing tube, a retractable bailing spear is connected to the lower end of the inverted bailing spear, and a round slip is arranged on the retractable bailing spear.

2. The composite fishing tool with inner and outer double slips according to claim 1, Features: The inverted bailing spear comprises an upper joint, an expansion sleeve and an expansion core shaft which are sequentially connected from top to bottom, and the upper joint is threadedly connected to the bailing tube.

3. The composite fishing tool with inner and outer double slips according to claim 2, Features: The retractable spear comprises a spear core shaft, a round slip and a guide cone. The spear core shaft is fixedly connected to the expansion core shaft. The spear core shaft is provided with a sawtooth thread. The round slip is arranged on the spear core shaft and the round slip teeth match the sawtooth thread. The guide cone is arranged at the bottom end of the spear core shaft.

4. The composite fishing tool with inner and outer double slips according to claim 3, Features: The diameter of the circular slip is greater than the diameter of the lance core shaft.

5. A method for fishing fish in a well, using a fishing string, wherein the fishing string comprises the inner and outer double slip composite fishing tool of claim 4, a fishing cup, a drill collar 5 column, a fishing cup and a drill pipe connected in sequence from bottom to top, Features: During salvage, the fish in the well first enters the salvage tool under the guidance of the anti-expansion sleeve, and then the guide cone enters the fish. The fish compresses the round slip and lifts the salvage pipe. The round slip teeth match the serrated threads on the spear core shaft to generate radial force, thereby biting the inner diameter of the fish to achieve salvage.

6. A method for recovering fish from a well according to claim 5, Features: When the strength of the fallen fish decreases due to corrosion, during the salvage process, the anti-expansion sleeve restricts the circumference of the fallen fish to prevent the fallen fish from being burst, thereby achieving salvage.

7. A method for recovering fish from a well according to claim 5, Features: When the fish is an oil pipe with a segmented hoop, the fish compresses the round slip and continues to move upward but is restricted by the limit structure at the bottom of the bailing tube. At this time, the tool is lifted, and the round slip teeth on the retractable bailing spear match the serrated threads on the bailing spear core shaft to generate radial force, thereby biting the inner diameter of the fish and achieving salvage.

8. A method for salvaging fish in a well according to claim 5, Features: When the fallen fish is the oil pipe body, the fallen fish compresses the round slip and moves up to pass through the slip teeth of the salvage tube until it is blocked by the limit at the upper joint. At this time, the salvage tool is lifted up, and the expansion sleeve moves down along the expansion core shaft to increase its outer diameter. The expansion sleeve bites the inner diameter of the oil pipe under the action of the radial force, and at the same time, the slip teeth of the salvage tube bite the outer diameter of the oil pipe under the action of the radial force of the inclined surface of the inner wall of the salvage tube. The round slip of the retractable salvaging spear at the lowest part of the tool also grabs the oil pipe from the inner wall of the fish falling oil pipe, and the three groups of slip teeth work together to grab the oil pipe inside and outside to achieve salvage.

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