Crossing type combined tool and salvage method

Abstract

The invention discloses a through type combined tool and a salvage method. A composite joint is connected with a female cone through a casing milling barrel; a circulating channel is arranged in the composite joint; the effective length of the casing milling barrel is not less than the length of the weak section of the fish at the upper part of the fishing position; the inner diameter of the milling cylinder is greater than the maximum outer diameter of the fish at the weak section of the fish at the fishing position; the maximum value of the inner diameter fishing range of the female tap is not smaller than the outer diameter of the fishing position of the fish target, and the minimum value of the inner diameter fishing range of the female tap is not larger than the outer diameter of the fishing position of the fish target. According to the invention, the combination of the composite joint, the casing milling barrel and the high-strength female tap is used as a carrier, so that accurate implementation of a through type complex fishing process is realized; the composite connector, the casing milling barrel and the female tap are connected through screw threads. The problems that a fish head which is damaged and seriously deformed and is reduced in tensile resistance and torsion resistance cannot effectively enter the fish and possibly cannot be effectively fished and a well is scrapped due to overhaul due to the fact that a conventional fishing process cannot effectively fish the fish head can be rapidly solved.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas development, and particularly relates to a through-type combined tool and a fishing method. Background Art

[0002] The history of complex fishing operations in high-temperature and high-pressure gas wells or workover wells in front of mountains in the Tarim Oilfield is nearly 20 years. During this period, traditional fishing techniques have been used to handle downhole complex situations. Due to the long time-consuming and low-efficiency of traditional fishing techniques in dealing with downhole complexities, it is extremely easy to cause the escalation of downhole complex situations. Especially when encountering situations where the fish head is damaged, deformed severely, and its tensile and torsional resistance is reduced due to external factors, it may be impossible to successfully fish the fallen fish even after a dozen fishing operations using conventional fishing techniques and conventional fishing tool combinations. It may even lead to the complete failure of the fishing operation and the escalation of the complexity of the fallen fish in the wellbore. More seriously, it may directly lead to the scrapping of major workover wells, ultimately resulting in the prominent contradictions of high downhole or workover operation costs, low efficiency, or the scrapping of gas production wells. In order to improve the efficiency of handling downhole or workover complexities, reduce workover operation costs, and lower downhole complex risks, it is extremely important to carry out research on downhole or workover complex treatment techniques and tool processing process flows. The present invention is an innovative through-type complex fishing technique and a supporting through-type combined tool developed based on the actual working conditions of on-site operation wells, aiming at the severely deformed fish head body and reduced tensile and torsional resistance, which cannot be fished using conventional fishing techniques.

[0003] The patent application with the publication number CN206016745U and the name of a through-type wide-area fishing barrel mainly includes three parts: a top joint, an upper barrel, and a lower barrel; a set of evenly distributed slip tooth blocks are respectively arranged on the upper barrel and the lower barrel, and the axial projections of the two sets of tooth blocks are also in an evenly distributed state; the roots of the tooth blocks are connected to the barrel by pins and are designed with springs. Each set of tooth blocks forms a complete closed surface in the natural state and can only be opened upward under external force. This patent application cannot effectively fish the fish head with severe damage, deformation, and reduced tensile and torsional resistance, and may result in the problems of ineffective fishing of the fallen fish and scrapping of major workover wells. Summary of the Invention

[0004] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a through-type combined tool and a fishing method, so as to quickly solve the problems that conventional fishing techniques cannot effectively fish the damaged, severely deformed fish head with reduced tensile and torsional resistance, and may lead to ineffective fishing of the fallen fish and scrapping of major workover wells.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A through-type combination tool, comprising: a composite joint, the composite joint is connected with a female taper through a milling barrel; a circulation channel is arranged inside the composite joint; the effective length of the milling barrel is not less than the length of the weak section of the fish body at the fishing position; the inner diameter of the milling barrel is greater than the maximum outer diameter of the fish body at the weak section of the fish body at the fishing position; the maximum value of the inner diameter fishing range of the female taper is not less than the outer diameter at the target fishing position of the fish body, and the minimum value of the inner diameter fishing range of the female taper is not greater than the outer diameter at the target fishing position of the fish body.

[0007] Optionally, the female taper is a high-strength female taper.

[0008] Optionally, when the outer diameter at the target fishing position is 88.9 mm, the inner diameter fishing range of the female taper is 85 mm to 100 mm.

[0009] Optionally, the length of the extended milling barrel exceeds the length of the weak section of the fish body at the fishing position by 0.5 m to 1 m.

[0010] Optionally, the female taper is provided with a hardened fishing tap inside.

[0011] Optionally, the composite joint is connected with the milling barrel by threads, and the milling barrel is connected with the female taper by threads.

[0012] A fishing method for a through-type combination tool, comprising the following steps:

[0013] S1: Lower the through-type combination tool above the fish top, start the pump and circulate smoothly before fishing, observe the changes of the pump pressure and the hook load. If the tool has entered the fish, set the high-pressure protection and stop the pump in time;

[0014] S2: Continue to lower the pipe string so that the fishing thread of the female taper passes through the weak point above the fish top to below the middle of the outer wall of the tubular fish, apply additional drilling pressure and rotate the drill string to force the fishing thread to squeeze into the outer wall of the fish for threading;

[0015] S3: After threading, if the hook load indicated by the weight indicator rises, lift the pipe string for threading. After lifting and threading, the threading ends;

[0016] S4: Lift or reverse the thread to fish out all or part of the fish body.

[0017] Optionally, before step S1, check the completion degree of the appearance of the composite joint, the milling barrel and the female taper.

[0018] Optionally, in step S1, lower the through-type combination tool to a range of 1 m to 2 m above the fish top, start the pump and circulate smoothly before fishing.

[0019] Optionally, in step S3, after threading 3 to 4 threads, if the hook load indicated by the weight indicator rises, lift the pipe string for threading; after lifting and threading 8 to 10 threads, when the hook load increases, the threading ends.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention uses a combination of a composite joint, a milling barrel, and a high-strength female taper as a carrier to accurately implement the through-type complex fishing process; the composite joint, the milling barrel, and the female taper are connected by screw threads. The effective length of the milling barrel is processed according to the determination of the length of the weak part of the fish head. The weak section of the fish is loaded into the milling barrel by lowering the pipe string and applying pressure. Then, appropriate drilling pressure is applied and the drill string is rotated to force the fishing screw threads of the female taper to squeeze and bite into the outer wall of the fish to make a thread. When the made thread can withstand a certain tensile force and torque, the fish is completely or partially fished out by lifting or unscrewing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to assist in understanding the present invention, rather than specifically limiting the shapes and proportional dimensions of the components of the present invention. In the drawings:

[0023] Figure 1 is a schematic cross-sectional view of the present invention;

[0024] Among them, 1, composite joint; 2, milling barrel; 3, female taper. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0026] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0028] The present invention will be described in detail below with reference to the accompanying drawings.

[0029] As Figure 1 shown, a through-type combination tool of the present invention includes: a composite joint 1, the composite joint 1 is connected to a female taper 3 through a milling barrel 2; a circulation channel is arranged inside the composite joint 1; the effective length of the milling barrel 2 is not less than the length of the weak section of the fish caught at the fishing position; the inner diameter of the milling barrel 2 is greater than the maximum outer diameter of the fish caught at the weak section of the fish caught at the fishing position; the maximum value of the inner diameter fishing range of the female taper 3 is not less than the outer diameter at the target fishing position of the fish dropped, and the minimum value of the inner diameter fishing range of the female taper 3 is not greater than the outer diameter at the target fishing position of the fish dropped.

[0030] The composite joint 1 can connect the drill string, has a circulation channel that meets the circulation requirements, and can transmit sufficient torque and tensile strength during the fishing process.

[0031] The inner diameter of the milling barrel 2 is greater than the maximum outer diameter of the fish caught at the weak section of the fish caught at the fishing position, and can transmit sufficient torque and tensile strength during the fishing process.

[0032] The outer diameter of the female taper 3 is smaller than the inner diameter of the wellbore. The inner diameter fishing range of the female taper 3 is not less than the outer diameter at the target fishing position of the fish dropped, and the minimum hole cleaning can meet the requirement of passing through the weak section of the fish caught at the fishing position. During the fishing process, it can meet the requirements of threading and related fishing techniques.

[0033] The inner diameter fishing range of the female taper 3 is determined according to the outer diameter at the target fishing position of the fish dropped. The outer diameter of the tool at the fishing position is within the fishing range of the female taper 3, and the minimum hole cleaning can meet the requirement of passing through the weak section of the fish caught at the fishing position. The female taper 3 has a fishing tap, the fishing tap and the female taper 3 are integrally formed, and the fishing tap is hardened.

[0034] Optionally, the outer diameter at the target fishing position is 88.9 mm, and the inner diameter fishing range of the female taper 3 is from 85 mm to 100 mm.

[0035] The effective length of the extended milling barrel 2 is not less than the length of the weak section of the fish caught at the fishing position.

[0036] Optionally, the length of the extended milling barrel 2 exceeds the length of the weak section of the fish caught at the fishing position by 0.5 m to 1 m.

[0037] Specifically, the length of the weak section of the upper part of the fishing position is 2 m, and the effective length of the extended milling barrel 2 is 2.5 m to 3 m.

[0038] After the weak section exists at the fish head due to its own material, corrosion, or milling, etc., when directly fishing the weak fish head with a female taper 3 or other tools, there may be a situation where it cannot be captured firmly. This device directly fishes the lower intact outer diameter fish by passing through the upper weak section of the fish, thereby increasing the fishing success rate and improving the fishing efficiency. Especially when the annular space of the casing is limited and the size of the lower fish is irregular, the effect is particularly obvious.

[0039] Under the action of the drilling pressure and torque, the fishing thread passes the vulnerable part of the fish head through the female taper 3 and introduces it into the milling barrel 2. Then, apply appropriate drilling pressure and rotate the drill string to introduce the lower part of the vulnerable fish head with a high tensile coefficient and anti-torque fish body into the through-type female taper 3, and at the same time make a thread on the outer wall of the dropped object for fishing; compared with the conventional fishing process, the success rate of fishing the dropped fish at one time is over 95%.

[0040] When using a through-type combined tool of the present invention, it includes the following steps:

[0041] Tool inspection: Check whether the appearance of the device of the present invention is complete and intact; check whether the tool size meets the requirements of wellbore well control and fishing tool size, including checking the outer diameter, inner diameter, length of the tool, the fishing range of the female taper 3, and the tensile and anti-torsion parameters of the tool; whether there is damage to the threaded connection thread of the tool, whether it meets the requirements of the pipe string and fishing technology requirements; whether the length and inner diameter of the extended milling barrel 2 meet the requirements for fishing the dropped fish to pass through.

[0042] S1: Lower to 1 - 2 m above the fish head, start the pump to circulate smoothly and then fish, observing the changes in pump pressure and hook load;

[0043] During the fishing process, observe the change in pump pressure. Record the normal circulating pump pressure before fishing. During the fishing process, if the tool enters the fish, there may be a phenomenon of pump pressure rising or pump jamming. It is necessary to pay attention that if it is judged that the tool has entered the fish, set high-pressure protection and stop the pump in time to prevent high pump pressure or pump jamming from causing high-pressure injury and fishing failure.

[0044] During the fishing process, observe the change in hook load. Record the initial hook load before fishing. During the process of making a thread with the female taper 3 for fishing, if the fishing is successful, when testing to lift the pipe string, the hook load will increase accordingly according to the situation of the lower fish. After ensuring that the dropped fish is caught, according to the actual situation, move the pipe string to release the stuck or back-off to fish the dropped fish.

[0045] S2: Continue to lower the pipe string to make the fishing thread of the female taper 3 pass through the upper weak point of the fish head to below the middle of the outer wall of the tubular dropped object, apply drilling pressure and rotate the drill string to force the fishing thread to squeeze and bite into the outer wall of the dropped object to make a thread.

[0046] S3: After screwing 3 - 4 threads, if the hook load on the weight indicator increases, lift the pipe string to screw. The load is 2 - 3 KN more than the original hook load. After lifting and screwing 8 - 10 threads, the hook load increases and the screwing ends.

[0047] S4: When the screwed part can withstand a certain pulling force and torque, lift or unscrew to fish out all or part of the fallen fish.

[0048] Embodiment

[0049] The present invention was first applied in Well DN21. The weak section at the upper part of the fallen fish was successfully avoided on site and the fallen fish was retrieved. It proves that the innovative design concept of the present invention has been successfully applied on site for the first time, achieving the improvement of the efficiency of downhole complex treatment, effectively reducing the workover cost, and efficiently preventing the escalation of downhole complex accidents.

[0050] When lowering the milling barrel 2 to a well depth of 4786.87 m, a resistance of 2 t was encountered. The milled section was from 4786.87 m to 4789.69 m, with a footage of 2.82 m. About 4.6 Kg of iron filings were returned at the outlet. The total milling time for this time was 18 h. After pulling out 2 stands of the milling barrel, upon pulling out the drill string for inspection, it was found that the milling and grinding integrated tool was severely worn. The alloy part of the milling shoe was worn by 12 mm, and the inner diameter was worn from 115 mm in diameter to 121 mm in diameter. There were multiple annular scratches on the body of the milling pipe, with the scratch width being 1 mm - 1.5 mm and the depth being 1.5 mm - 2 mm. There was a section of the perforating gun residue in the milling shoe, with a length of 480 mm, the thickest part of the residue being 6 mm, and the upper part being curled and wound into a conical shape. 2.5 Kg of iron filings and iron sheets were brought out by the fishing cup, among which the largest piece of the perforating gun residue skin was 490 * 120 * 3 mm; The situation of the fallen fish from top to bottom in the well: perforating gun residue + 73 perforating guns + delay detonator + gun tail. The expected fish top position: 4786.93 m, and the total length of the fallen fish was 321.39 m.

[0051] Using the through - type combination tool and fishing method of the present invention, lower the through - type fishing female taper 3 for fishing. One piece of perforating gun residue and 10 complete perforating guns were retrieved at one time, and the total length of the retrieved fallen fish was 41.83 m. The upper part of the perforating gun residue was in an incomplete split state, and the surface of the gun body was severely scaled; The example verifies that the innovative idea of the present invention is embodied.

[0052] In the above embodiments, the equipment components involved, if not otherwise specified, are all conventional equipment components. The structural setting methods, working methods, or control methods involved, if not otherwise specified, are all conventional setting methods, working methods, or control methods in the art.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should all be covered within the scope of the claims of the present invention.

Claims

1. A through - type combined tool, characterized in that, it includes: A composite joint (1), the composite joint (1) is connected with a female taper (3) through a milling barrel (2); a circulation channel is arranged inside the composite joint (1); the effective length of the milling barrel (2) is not less than the length of the weak section of the fish body at the fishing position; the inner diameter of the milling barrel (2) is greater than the maximum outer diameter of the fish body at the weak section at the fishing position; the maximum value of the inner diameter fishing range of the female taper (3) is not less than the outer diameter at the target fishing position of the fish body, and the minimum value of the inner diameter fishing range of the female taper (3) is not greater than the outer diameter at the target fishing position of the fish body.

2. The through - type combined tool according to claim 1, characterized in that, the female taper (3) is a high - strength female taper.

3. The through - type combined tool according to claim 1, characterized in that, when the outer diameter at the target fishing position is 88.9 mm, the inner diameter fishing range of the female taper (3) is from 85 mm to 100 mm.

4. The through - type combined tool according to claim 1, characterized in that, the length of the extended milling barrel (2) exceeds the length of the weak section of the fish body at the fishing position by 0.5 m to 1 m.

5. The through - type combined tool according to claim 1, characterized in that, the female taper (3) has hardened fishing taps inside.

6. The through - type combined tool according to claim 1, characterized in that, the composite joint (1) is connected with the milling barrel (2) by threads, and the milling barrel (2) is connected with the female taper (3) by threads.

7. A fishing method for a through - type combined tool, characterized in that, it includes the following steps: S1: Lower the through - type combined tool to above the fish top, start the pump and circulate until it is unobstructed, then fish, observe the changes in pump pressure and hook load. If the fish has been entered, set high - pressure protection and stop the pump in time; S2: Continue to lower the pipe string so that the fishing threads of the female taper (3) pass through the upper weak point of the fish top to below the middle of the outer wall of the tubular fish body, apply drilling pressure and rotate the drill string to force the fishing threads to squeeze and bite into the outer wall of the fish body to make a thread; S3: After making a thread, if the hook load indicated by the weight indicator rises, lift the pipe string to make a thread. After lifting and making a thread, the thread - making ends; S4: Lift or reverse - turn to fish out all or part of the fish body.

8. The fishing method for a through - type combined tool according to claim 7, characterized in that, before step S1, check the completion degree of the appearance of the composite joint (1), the milling barrel (2) and the female taper (3).

9. The fishing method for a through - type combined tool according to claim 7, characterized in that, in step S1, lower the through - type combined tool to the range of 1 m to 2 m above the fish top, start the pump and circulate until it is unobstructed, then fish.

10. The fishing method for a through - type combined tool according to claim 7, characterized in that, in step S3, after making 3 to 4 threads, if the hook load indicated by the weight indicator rises, lift the pipe string to make a thread; after lifting and making 8 to 10 threads, the hook load increases and the thread - making ends.

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