Coiled tubing sticking point underground cutting tool and application method thereof

Abstract

The invention provides a coiled tubing sticking point underground cutting device and an application method thereof. The coiled tubing sticking point underground cutting device comprises a sectioning outer sleeve body, an anchoring and cutting mechanism, a recycling and fixing mechanism and a sectioning type cylindrical weighting and exciting mechanism. The recovery fixing mechanism is connected with the anchoring and cutting mechanism through the sectioning outer sleeve body, the sectioning outer sleeve body is used for bearing all parts of the recovery fixing mechanism and the anchoring and cutting mechanism, and after cutting is completed, all mechanism assemblies are recovered and brought out. Irreversible damage such as plastic deformation, buckling deformation and the like of the coiled tubing oil pipe caused by large-force drawing movable unfreezing is avoided, and the maximum advantage is that it is guaranteed that the coiled tubing on the upper portion of a cutting point is complete and can be continuously used.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to a downhole cutting tool for a stuck coiled tubing and an application method thereof, and specifically relates to a downhole cutting tool for unblocking a coiled tubing string when the coiled tubing string itself is stuck during coiled tubing construction and an application method thereof. Background Art

[0002] Coiled tubing operation technology is widely used in the field of oil and gas field exploration and development. It is inevitable that the coiled tubing string will get stuck. However, in the process of handling the coiled tubing string when it gets stuck, it is difficult to use conventional methods to unblock and salvage it due to its small diameter, strong elasticity, high toughness and inability to rotate. The usual unblocking method can only be to pull it vigorously, and then salvage it in sections after breaking it off, causing the coiled tubing to be scrapped. Its construction procedure is complicated and the cycle is long. Although chemical cutting and shaped charge bombs can also be used at present, they require wellhead cutting and well killing, and are prone to corrosion damage to the oil casing, resulting in a high construction risk, which limits their use.

[0003] Internationally, a cable-transmitted small-diameter hot-melt internal cutting tool is used to release stuck pipes for salvage. However, this is because it requires the use of high-energy fuel to produce ion beam cutting, requires secondary hole opening balance, requires well pressure, has irregular fish tops after cutting, requires cutting of continuous tubing at the wellhead, and requires the use of high-load lifting equipment. There are many restrictions on its use, so a continuous tubing string downhole cutting tool has been developed for this purpose. Summary of the invention

[0004] The purpose of the present invention is to make up for the shortcomings of the prior art and provide a downhole cutting tool for a coiled tubing stuck point and an application method thereof. The coiled tubing can be cut from the downhole stuck point by inserting a set of tools without cutting at the wellhead, so as to overcome the shortcomings of the prior art such as strong pulling, segmented fishing after breaking off, wellhead cutting, and the need for well pressure.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] In a first aspect, a downhole cutting tool for a coiled tubing stuck point includes a petal outer sleeve, an anchoring and cutting mechanism, a recovery and fixing mechanism, and a petal-type cylinder-type weighted excitation mechanism;

[0007] The recovery and fixing mechanism is connected to the anchoring and cutting mechanism through the petal outer sleeve body, and the petal outer sleeve body is used to receive all the components of the recovery and fixing mechanism and the anchoring and cutting mechanism;

[0008] The recovery and fixing mechanism comprises a split-type recovery slip group and a split-type cylindrical cone slip sleeve, wherein the split-type recovery slip group and the split-type cylindrical cone slip sleeve form a self-locking anchor to fix the cutting tool device on the coiled tubing;

[0009] The anchoring and cutting mechanism comprises a split cutter key plate group and a split anchoring slip group. The split anchoring slip petal body is engaged and anchored with the production pipe string to form a cutting force point, and the split cutter key plate group is tightened inward to cut the coiled tubing.

[0010] The weighted activation mechanism is a split-petal cylindrical weighted body, which is used to impact the shear pin and activate the cutting and salvaging tool when the coiled tubing string is stuck;

[0011] Wherein, the split outer sleeve body is anchored and connected to the split cylindrical cone slip sleeve, and the split cylindrical cone slip sleeve is connected to the split recovery slip group through a first shear pin;

[0012] The split-type anchoring slip group is assembled in the split-type outer sleeve body, the split-type anchoring slip group is connected to the split-type cutter key plate group through a second shear pin, and the split-type cutter key plate group is formed into an enclosed body through a U-shaped cutter key plate recovery hanging spring and is movably connected to the split-type outer sleeve body through the U-shaped cutter key plate recovery hanging spring;

[0013] The cutting tool device is connected with a split cutter key plate group, a split anchoring cava group, a split outer sleeve body, a split recovery cava group, and a split cylindrical cone cava sleeve in sequence from bottom to top. When in the excited state, a split cylindrical weighted excitation mechanism is provided on the split outer sleeve body.

[0014] Preferably, the petal outer sleeve body is an inverted L-shaped structure surrounded by six petals, including a petal sleeve fixing pin hole groove, a sleeve window and a spring pin hole groove, and the top of the petal outer sleeve body is provided with two petal sleeve fixing pin hole grooves, the upper part is provided with a sleeve window, and the lower part is provided with two spring pin hole grooves; wherein, the sleeve window is rectangular, used to accommodate a fixed cava, and the length of the sleeve window is greater than the cava tooth block body.

[0015] Preferably, one side of the U-shaped cutter key plate recovery spring is fixed to the petal outer sleeve through a recovery spring cylinder fixing pin, and the other side is passed through the petal body of the petal cutter key plate group through a recovery spring cutter key plate fixing hook; wherein the spring cylinder fixing pin is connected to the spring pin hole groove.

[0016] Preferably, the split-petal recovery slip group is a six-petal combination structure, each petal body comprises a recovery slip, a recovery slip self-locking inclined surface, a recovery slip shear pin hole and a recovery slip tooth, and each petal body of the split-petal recovery slip group is provided with a recovery slip tooth inside, and each petal body is provided with a recovery slip self-locking inclined surface outside;

[0017] The split-petal cylindrical cone slip sleeve is a cylindrical combination structure surrounded by two petals, each petal body includes a recovery slip cone sleeve, a recovery slip cone sleeve self-locking inclined surface and a recovery slip cone sleeve shear pin hole, the split-petal cylindrical cone slip sleeve is provided with a mortise and tenon structure insertion key and keyway running through the upper and lower parts, a pin is provided near the upper part for fixing, a recovery slip cone sleeve shear pin hole is provided at the lower part, and the interior is a hexagonal inclined surface cavity, and the recovery slip cone sleeve self-locking inclined surface is formed in the inclined cavity;

[0018] The self-locking inclined surface of the recovery slip cone sleeve cooperates with the self-locking inclined surface of the recovery slip to form self-locking, and the shear pin hole of the slip cone sleeve is connected with the corresponding recovery slip pin hole through the first shear pin.

[0019] Preferably, the split-petal anchoring slip group is a six-petal combination structure, each petal body comprises an anchoring slip, an anchoring slip inclined surface, an anchoring slip hoop spring groove, an anchoring slip shear pin hole and an anchoring slip tooth, the outer side surface of each petal body is provided with an anchoring slip tooth, the inner side is provided with an anchoring slip inclined surface, and the lower end is provided with an anchoring slip shear pin hole, the split-petal anchoring slip group is assembled in the split-petal outer sleeve body, the anchoring slip tooth is exposed on the sleeve window, and the anchoring slip tooth is used to engage and anchor with the production pipe string;

[0020] The split cutter key plate group is a six-petal combination structure, each petal body includes an anchoring slip spring, a cutter key plate inclined surface, a cutter key plate shear pin hole and a cutter, one side of each petal body is provided with a cutting knife, and the upper end of the other side is provided with a cutter key plate inclined surface, the cutter key plate inclined surface is provided with a cutter key plate shear pin hole, the bottom end is a flat end, and the edge is cut at an angle to guide the insertion;

[0021] Among them, the inclined surface of the anchoring slip cooperates with the inclined surface of the cutter key plate; the shear pin hole of the anchoring slip is connected with the shear pin hole of the cutter key plate through the second shear pin; the anchoring slip hoop spring is clamped with the anchoring slip hoop spring groove, so as to enable the petals of the split-petal anchoring slip group to be enclosed on the blocked continuous oil pipe string.

[0022] Preferably, the petal-type cylindrical weighted excitation mechanism is a cylindrical combination structure surrounded by two petals, each petal including a petal-type cylindrical weighted excitation cylinder, a dovetail-shaped anchor block, and a fixing pin. The two petals of the petal-type cylindrical weighted excitation cylinder are inserted into each other's square arc grooves and are positioned and locked by the dovetail-shaped anchor block and the fixing pin.

[0023] In a second aspect, a method for applying a downhole cutting tool for a stuck coiled tubing includes the following contents:

[0024] Step 1: Select the appropriate size of coiled tubing string cutting and salvage tool, close the semi-closed gate and slip gate, release the injection head after the slip is loaded, and then open the blowout preventer.

[0025] Step 2: Install the anchoring and cutting mechanism and the recovery and fixing mechanism, install the tool string, check it, and then lift the tool into the blowout preventer;

[0026] Step 3: Apply a certain upward load tension through the injection head to make the coiled tubing basically in a straight state, and open the semi-closed gate and the slip gate;

[0027] Step 4: Release the installed cutting tool string and let it fall along the stuck coiled tubing by itself;

[0028] Step 5: Close the semi-closed gate and the slip gate, release the injection head after the slip is loaded, and then open the blowout preventer;

[0029] Step 6: Install the tool string of the split-type cylindrical weighted excitation device, check it, and then lift the tool into the blowout preventer;

[0030] Step 7: Apply a certain upward load tension through the injection head to make the coiled tubing basically in a straight state, open the semi-closed gate and the slip gate, and put the petal-type cylindrical weighted excitation mechanism into use to make it fall along the stuck coiled tubing by itself;

[0031] Step 8: Lift up the stuck coiled tubing string, tighten the cutter and cut the coiled tubing body.

[0032] Step 9: After the stuck coiled tubing string is pulled off, the cutter becomes free and the split-type anchoring slip group is released from anchoring.

[0033] Step 10: Take out the stuck coiled tubing string and cutting tool to complete the unblocking and salvaging work.

[0034] Preferably, the downhole cutting device for the stuck point of the continuous oil tubing is of a petal-type design. It is lowered into the well without cutting the continuous oil tubing, and the continuous oil tubing is effectively stress-cut under the external force of the excitation device. The continuous oil tubing is then lifted up to ensure that the continuous oil tubing breaks at the stuck point without plastic deformation. At the same time, the downhole cutting device for the stuck point of the continuous oil tubing can be lifted out of the wellhead along with the broken continuous oil tubing.

[0035] The embodiments of the present invention bring the following beneficial effects:

[0036] The present invention avoids irreversible damage to the coiled tubing caused by vigorous pulling and active jamming, such as plastic deformation and buckling deformation, and has the greatest advantage of ensuring that the coiled tubing above the cutting point is intact and can continue to be used.

[0037] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of a running state of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of the structure of a split outer sleeve body of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the structure of a split-type recovery slip group of a downhole cutting tool for a stuck coiled tubing provided by an embodiment of the present invention;

[0043] Figure 5 A schematic diagram of a split cone slip sleeve structure of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0044] Figure 6 A schematic diagram of the structure of a split-type anchoring slip group of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0045] Figure 7 A schematic diagram of the structure of a split cutter key plate assembly of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0046] Figure 8 A schematic diagram of a retrieving hanging spring and a connecting structure of a split cutter key plate of a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention;

[0047] Fig. 9 A schematic diagram of a split-petal cylindrical weighted excitation device for a downhole cutting tool for a coiled tubing stuck point provided by an embodiment of the present invention.

[0048] In the figure, 1-stuck coiled tubing string, 2-split outer sleeve, 3-recovery slip cone sleeve, 4-split recovery slip group, 5-split anchoring slip group, 6-anchoring slip hoop spring, 7-split cutter key plate group, 8-cutter key plate recovery hanging spring, 9-production string (original string in the well);

[0049] 10-pin hole slot for fixing the split cylinder, 11-cylinder window, 12-pin hole slot for hanging spring;

[0050] 13-recovery slip cone sleeve self-locking inclined surface, 14-recovery slip self-locking inclined surface, 15-recovery slip cone sleeve shear pin hole; 16-recovery slip shear pin hole, 17-first shear pin, 18-recovery slip teeth;

[0051] 19-anchoring slip inclined surface, 20-cutter key plate inclined surface, 21-anchoring slip hoop spring groove, 22-anchoring slip shear pin hole, 23-cutter key plate shear pin hole, 24-second shear pin, 25-anchoring slip tooth, 26-cutting knife, 27-recovery hanging spring cylinder fixing pin, 28-recovery hanging spring cutter key plate fixing hook;

[0052] 29-petaled cylindrical weighted excitation cylinder, 30-dovetail anchor block, 31-fixing pin. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Embodiment 1, as Figure 1-Figure 2 As shown, a downhole cutting tool for a coiled tubing stuck point is provided, including a petal outer sleeve, an anchoring and cutting mechanism, a recovery and fixing mechanism, and a petal-type cylindrical weighted excitation mechanism. All mechanisms and devices adopt a petal body enclosing device to facilitate the installation of the tool without cutting the coiled tubing at the wellhead.

[0055] The petal outer sleeve body 2 is used to receive all components such as the recovery and fixing mechanism, the anchoring and cutting mechanism, etc. The recovery and fixing mechanism is connected to the anchoring and cutting mechanism through the petal outer sleeve body device. After the cutting is completed, all the mechanism components are recovered and taken out;

[0056] like Figure 3 As shown, the structure of the split outer sleeve body 2 is a six-petal "inverted L-shape", which is used to support all tools and recover the anchoring and cutting mechanism components after cutting. Each petal body includes a split cylinder fixing pin hole slot 10, a cylinder window 11 and a spring pin hole slot 12. The top of the split outer sleeve body 2 is provided with two split cylinder fixing pin hole slots 10, which are fixed by pins and the recovery slip cone sleeve 3; the upper part is provided with a cylinder window 11 for accommodating the fixed slip, and the length is greater than the slip tooth block to form the up and down movement range of the shear pin; the lower part is provided with two spring pin hole slots;

[0057] In this embodiment, the recovery and fixing mechanism includes a split-type recovery slip group 4 and a split-type cylindrical cone slip sleeve 3. The self-locking anchoring is achieved through the self-locking surface, so that the entire set of tools is always fixed on the continuous oil pipe. After the cutting is completed, all the mechanism components are recovered and taken out by relying on its fixation.

[0058] like Figure 4 As shown, the split-petal recovery slip group 4 is a combination of six petals, which is used to engage with the blocked coiled tubing string 1 during cutting and salvaging and anchor by self-locking through the self-locking surface. Each petal body includes a recovery slip self-locking inclined surface 14, a recovery slip shear pin hole 16 and a recovery slip tooth 18.

[0059] Furthermore, each petal body is provided with recovery slip teeth 18 on its inner surface, and a recovery slip self-locking inclined surface 14 with a taper of 7°19′ is provided on its outer surface, and the corresponding petals are connected with first shear pins 17 respectively.

[0060] like Figure 5 As shown, the split cylindrical cone slip sleeve 3 is a cylindrical assembly surrounded by two petals, which is used to form a fixing mechanism with the inwardly contracted split recovery slip 4 and fix it on the blocked coiled tubing string 1. Each petal body includes a recovery slip cone sleeve self-locking inclined surface 13 and a recovery slip cone sleeve shear pin hole 15.

[0061] Furthermore, the split cylindrical cone cava sleeve 3 is provided with a mortise and tenon structure key and keyway running through the upper and lower parts, a pin fixation is provided near the upper part, a recovery cava cone sleeve shear pin hole 15 is provided at the lower part, and the interior is a hexagonal inclined cavity, and a recovery cava cone sleeve self-locking inclined surface 13 with a taper of 7°19′ is formed in the inclined cavity.

[0062] The self-locking inclined surface 13 of the recovery slip cone sleeve cooperates with the self-locking inclined surface 14 of the recovery slip to form self-locking, and the shear pin hole 15 of the recovery slip cone sleeve is connected with the corresponding recovery slip shear pin hole 16 through the first shear pin 17.

[0063] In this embodiment, the anchoring and cutting mechanism includes a split cutter key plate group 7, a split anchoring cava group 5, and a split cutter key plate recovery spring 8. The split anchoring cava group 5 is engaged and anchored with the production tubing 9 to form a cutting force point, and the split cutter key plate group 7 is tightened inward to cut the continuous oil tubing.

[0064] like Figure 6As shown, the split-flap anchoring slip group 5 is a six-flap combination, which is assembled in the split-flap outer sleeve body 2, and each flap body includes an anchoring slip inclined surface 19, an anchoring slip hoop spring groove 21, an anchoring slip shear pin hole 22, and an anchoring slip tooth 25. The outer side of each flap body is provided with an anchoring slip tooth 25, the inner side is provided with an anchoring slip inclined surface 19, and the lower end is provided with an anchoring slip shear pin hole 22. The split-flap anchoring slip group 5 is assembled in the split-flap outer sleeve body, and the anchoring slip tooth 25 is exposed on the sleeve window 11. The anchoring slip tooth 25 is used to engage and anchor with the production pipe string 9 and can tighten the split-flap cutter key plate group 7 inward to cut (cut) the blocked continuous oil pipe string 1.

[0065] like Figure 7 As shown, the split cutter key plate group 7 is a combination of six petals, each petal body includes an anchoring cava hoop spring 6, a cutter key plate inclined surface 20, a cutter key plate shear pin hole 23, and a cutting knife 26, wherein each petal body is provided with a cutting knife 26 on one side, and a cutter key plate inclined surface 20 with a taper of 7°19′ is provided on the upper end of the other side, which is used to cooperate with the corresponding anchoring cava inclined surface 19, and a cutter key plate shear pin hole 23 is opened on the cutter key plate inclined surface 20, the bottom end is a flat end, and the edge is cut at an angle to guide the entry.

[0066] Among them, the anchoring slip tooth 25 has a 90° structural angle and is bidirectionally anchored. A cutter cone seat with an anchoring slip bevel 19 and a self-locking angle of 7°19′ is provided on the inner side. The anchoring slip bevel 19 cooperates with the corresponding cutter key plate bevel 20. The anchoring slip shear pin hole 22 is connected with the corresponding cutter key plate shear pin hole 23 through a second shear pin 24. The anchoring slip hoop spring 6 is clamped with the anchoring slip hoop spring groove 21 to enable the petals of the split-petal anchoring slip group to be enclosed on the blocked continuous oil pipe string 1.

[0067] Furthermore, each petal of each split cutter key plate group 7 is provided with a recovery spring cutter key plate fixing hook 28, and the recovery spring cutter key plate fixing hook 28 is welded to each petal of the split cutter key plate.

[0068] In this embodiment, the split outer sleeve body 2 further includes a U-shaped cutter key plate recovery spring 8. Figure 8 As shown, one side of the U-shaped cutter key plate recovery spring 8 is fixed to the split outer sleeve 2 through the recovery spring cylinder fixing pin 27, and the other side is passed through the leaf spring groove of the split cutter key plate group 7 through the recovery spring cutter key plate fixing hook 28, and can move up and down in the fixing hook; wherein, the spring cylinder fixing pin 27 is connected to the spring pin hole groove 12.

[0069] Furthermore, the function of the U-shaped cutter key plate recovery hanging spring 8 is to make the cutter of the split cutter key plate group 7 close to the stuck continuous oil pipe string 1; secondly, when the cutting is completed, the continuous oil pipe string is lifted up, and the split anchoring cava group 5 is driven upward along the lower edge of the upper cylinder window 11 of the outer sleeve body 2, so that the self-locking of the anchoring cava slope 19 and the cutter key plate slope 20 is eliminated, and after the split anchoring cava 5 is released and anchored, the continuous oil pipe attached to the inner circle of the split cutter key plate group 7 is removed and falls apart. At this time, the U-shaped cutter key plate recovery hanging spring 8 hooks the split cutter key plate group 7 and is taken out with the outer sleeve body 2; thirdly, the U-shaped cutter key plate recovery hanging spring 8 can move up and down in the handle to form an up and down moving range of the shear pin.

[0070] In this embodiment, the weighted activation mechanism is a split-petal cylindrical weighted body, which is used to strike the shear pin and activate the cutting and salvaging tool when the coiled tubing string is stuck;

[0071] like Fig. 9 As shown, the petal-type cylindrical weighted excitation mechanism includes a petal-type cylindrical weighted excitation cylinder body 29 , a dovetail anchor block 30 , and a fixing pin 31 .

[0072] Furthermore, the petal-type cylinder-type weighted excitation cylinder 29 is made of tungsten-nickel-iron with a relatively high density (18.75 g / cm 3 ), the left and right shells of the two halves are inserted into each other's square arc grooves, and are positioned and locked with a dovetail anchor block 30 and a fixing pin 31 to form a complete circular shell.

[0073] In this embodiment, the cutting tool device is connected in sequence from bottom to top with a split cutter key plate group 7, a split anchoring cava group 5, a split outer sleeve body 2, a split recovery cava group 4, a split cylindrical cone cava sleeve 3 and a split cylindrical weighted excitation mechanism 9 for activating the cutter.

[0074] Embodiment 2 provides an application method of a downhole cutting tool for a stuck coiled tubing, comprising the following contents:

[0075] Step 1: Select the appropriate size of coiled tubing string cutting and salvage tool, close the semi-closed gate and slip gate, release the injection head after the slip is loaded, and then open the blowout preventer.

[0076] Step 2: Install the anchoring and cutting mechanism, the recovery fixing mechanism and the split outer sleeve body, and after inspection, lift the tool string into the blowout preventer;

[0077] Specifically, the split recovery slip group 4 in the recovery fixing mechanism is matched with the corresponding first shear pin 17 to enclose the stuck coiled tubing string 1;

[0078] After the split cone cutter key plate set 7 in the anchoring and cutting mechanism is matched with the corresponding second shear pin 24, it is enclosed on the blocked coiled tubing string 1 through the anchoring slip hoop spring 6;

[0079] Insert the split outer sleeve body 2, connect and cooperate with the corresponding split anchoring cava group 5, split cutter key plate group 7, and U-shaped cutter key plate recovery hanging spring 8, and then use screws to pass through the split sleeve body fixing pin hole groove 10 and fix it with the corresponding pin hole on the top of the split recovery cava cone sleeve 3.

[0080] Step 3: Apply a certain upward load tension through the injection head to keep the coiled tubing basically in a straight state, and open the semi-closed gate and slip gate.

[0081] Step 4: Release the installed cutting tool string and let it fall along the stuck coiled tubing. During this period, the coiled tubing can be moved slightly (relax the tension and lift the tension - it must not exceed the original lifting tension);

[0082] Specifically, the entire cutting tool string is dropped into the well along the stuck coiled tubing string 1, and the cutting tool is allowed to fall along the stuck coiled tubing by itself. During this period, the coiled tubing can be slightly moved to creep and straighten it, helping the cutting tool string to descend to the stuck position.

[0083] Step 5: Close the semi-closed gate and the slip gate, release the injection head after the slip is loaded, and then open the blowout preventer;

[0084] Step 6: Install the split-type cylindrical weighted excitation mechanism, and after inspection, lift the tool string into the blowout preventer;

[0085] Specifically, the split-type cylindrical weighted excitation mechanism is put into use, and the tool string is impacted under the action of gravity, thereby shearing the two pins of "split-type recovery cava group 4 and corresponding split-type cylindrical cone cava sleeve 3" and "split-type cutter key plate group 7 and corresponding split-type anchoring cava group 5", namely the first shear pin 17 and the second shear pin 24.

[0086] The split recovery slip group 4 is tightened and clamped to the coiled tubing 1 during the downward movement of the split cylindrical cone slip sleeve 3, and is fixed under the effect of the self-locking angle. At the same time, the cutter key plate inclined surface 20 of the split cutter key plate group 7 cooperates with the anchoring slip inclined surface 19 of the split anchoring slip group 5, and the cutting knife 26 is tightened and cuts into the coiled tubing 1 body, and the split anchoring slip group 5 is clamped to the inner wall of the production string 9 to form a fulcrum.

[0087] Step 7: Apply a certain lifting load tension through the injection head to make the coiled tubing basically in a straight state, open the semi-closed gate and the slip gate, and put into the split-petal cylindrical weighted excitation mechanism to make it fall along the stuck coiled tubing by itself. During this period, the coiled tubing can be moved slightly (relaxation tension, lifting tension-not exceeding the original lifting tension);

[0088] Step 8, lift the stuck coiled tubing string 1, the cutter 26 is tightened under the action of the anchor slip inclined surface 19 and the cutter key plate inclined surface 20, and cuts the coiled tubing body; continue to move the coiled tubing up and down, the cutter 26 gradually cuts into the stuck coiled tubing string 1 body, forming a stress concentration point, and the stuck coiled tubing string 1 is pulled off under a certain lifting load.

[0089] Step 9: After the stuck coiled tubing string 1 is pulled off, the cutting knife 26 becomes free and the split-type anchoring slip group 5 is released from anchoring.

[0090] Step 10: Pull out the coiled tubing and tool string to complete the unblocking and salvaging work;

[0091] Specifically, the stuck coiled tubing string 1 is lifted up, and the recovery and fixing mechanism device fixed on the coiled tubing string is driven by the split outer sleeve body 2 to lift the "recovery and fixing mechanism device" that is released from the fixed state and move together with the coiled tubing to the ground.

[0092] In this embodiment, the downhole cutting device for the stuck point of the continuous oil tubing is of a split-petal design. It is lowered into the well without cutting the continuous oil tubing, and the continuous oil tubing is effectively stress-cut under the external force of the excitation device. Then, the continuous oil tubing is lifted up to ensure that the continuous oil tubing breaks at the stuck point without plastic deformation. At the same time, the downhole cutting device for the stuck point of the continuous oil tubing can be lifted out of the wellhead along with the broken continuous oil tubing.

[0093] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0094] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A downhole cutting tool device for coiled tubing stuck point, characterized in that: It includes a split outer sleeve body, an anchoring and cutting mechanism, a recovery and fixing mechanism, and a split-type cylinder-type weighted excitation mechanism; The recovery and fixing mechanism and the anchoring and cutting mechanism are connected through the petal outer sleeve body, and the petal outer sleeve body is used to receive all the components of the recovery and fixing mechanism and the anchoring and cutting mechanism; The petal outer sleeve body is an inverted L-shaped structure surrounded by six petals, each petal body includes a petal sleeve fixing pin hole groove, a sleeve window body and a hanging spring pin hole groove, the top of the petal outer sleeve body is provided with two petal sleeve fixing pin hole grooves, the upper part is provided with a sleeve window body, and the lower part is provided with two hanging spring pin hole grooves; The recovery fixing mechanism comprises a petal recovery slip group and a petal cylindrical cone slip sleeve. The petal recovery slip group is a six-petal combination structure, and the petal cylindrical cone slip sleeve is a two-petal combination. The petal recovery slip group and the petal cylindrical cone slip sleeve form a self-locking anchor to fix the cutting tool device on the coiled tubing. The anchoring and cutting mechanism comprises a split cutter key plate group and a split anchoring slip group, both of which are a six-petal combination structure, the split anchoring slip group is engaged and anchored with the production string to form a cutting force point, and the split cutter key plate group is tightened inward to cut the coiled tubing; The split-petal cylindrical weighted activation mechanism is a combined structure of two petals, used to impact the shear pin and activate the cutting and salvaging tool when the coiled tubing string is stuck; Wherein, the split outer sleeve body is anchored and connected to the split cylindrical cone slip sleeve, and the split cylindrical cone slip sleeve is connected to the split recovery slip group through a first shear pin; The split-type anchoring slip group is assembled in the split-type outer sleeve body, the split-type anchoring slip group is connected to the split-type cutter key plate group through a second shear pin, and the split-type cutter key plate group is formed into an enclosed body through a U-shaped cutter key plate recovery hanging spring and is movably connected to the split-type outer sleeve body through the U-shaped cutter key plate recovery hanging spring; The cutting tool device is connected with a split cutter key plate group, a split anchoring cava group, a split outer sleeve body, a split recovery cava group, and a split cylindrical cone cava sleeve in sequence from bottom to top. When in the excited state, a split cylindrical weighted excitation mechanism is provided on the split outer sleeve body.

2. The downhole cutting device for coiled tubing stuck point according to claim 1 is characterized in that: The barrel window on the split outer barrel body is rectangular and is used to accommodate the fixed slips, and the length of the barrel window is greater than the slip tooth block body.

3. The coiled tubing stuck downhole cutting device according to claim 2, characterized in that: One side of the U-shaped cutter key plate recovery spring is fixed to the split-petal outer sleeve body through the recovery spring sleeve body fixing pin, and the other side is passed through the split-petal cutter key plate petal body through the recovery spring cutter key plate fixing hook; Wherein, the hanging spring cylinder fixing pin is connected with the hanging spring pin hole groove.

4. The coiled tubing stuck downhole cutting device according to claim 1, wherein the recovery and fixing mechanism comprises a split-type recovery slip group and a split-type cylindrical cone slip sleeve, characterized in that: Each petal of the split-petal recovery slip group includes a recovery slip, a recovery slip self-locking inclined surface, a recovery slip shear pin hole, and a recovery slip tooth. The inner surface of each petal of the split-petal recovery slip group is provided with a recovery slip tooth, and the outer surface of each petal is provided with a recovery slip self-locking inclined surface. Each petal of the split-petal cylindrical cone slip sleeve includes a recovery slip cone sleeve, a recovery slip cone sleeve self-locking inclined surface and a recovery slip cone sleeve shear pin hole. The split-petal cylindrical cone slip sleeve is provided with a mortise and tenon structure insertion key and a keyway running through the upper and lower parts, a pin is provided near the upper part for fixing, a recovery slip cone sleeve shear pin hole is provided at the lower part, and the interior is a hexagonal inclined surface cavity, and a recovery slip cone sleeve self-locking inclined surface is formed in the inclined cavity; The self-locking inclined surface of the recovery slip cone sleeve cooperates with the self-locking inclined surface of the recovery slip to form self-locking, and the shear pin hole of the slip cone sleeve is connected with the corresponding recovery slip pin hole through the first shear pin.

5. According to the downhole cutting device for coiled tubing stuck points in claim 1, the anchoring and cutting mechanism comprises a split cutter key plate group and a split anchoring slip group, characterized in that: Each petal of the split-type anchoring slip group includes an anchoring slip, an anchoring slip inclined surface, an anchoring slip hoop spring groove, an anchoring slip shear pin hole and an anchoring slip tooth. An anchoring slip tooth is provided on the outer side surface of each petal, an anchoring slip inclined surface is provided on the inner side, and an anchoring slip shear pin hole is provided at the lower end. The split-type anchoring slip group is assembled in the split-type outer sleeve body, and the anchoring slip tooth is exposed on the sleeve window. The anchoring slip tooth is used to engage and anchor with the production pipe string; Each petal of the split cutter key plate group includes an anchoring slip spring, a cutter key plate inclined surface, a cutter key plate shear pin hole and a cutter. Each petal is provided with a cutting knife on one side and a cutter key plate inclined surface on the other upper side. The cutter key plate inclined surface is provided with a cutter key plate shear pin hole, the bottom end is a flat end, and the edge is cut at an angle to guide the insertion. Among them, the inclined surface of the anchoring slip cooperates with the inclined surface of the cutter key plate; the shear pin hole of the anchoring slip is connected with the shear pin hole of the cutter key plate through the second shear pin; the anchoring slip hoop spring is clamped with the anchoring slip hoop spring groove, so as to enable the petals of the split-petal anchoring slip group to be enclosed on the blocked continuous oil pipe string.

6. The downhole cutting device for coiled tubing stuck point according to claim 1, characterized in that: Each petal of the petal-type cylindrical weighted excitation mechanism includes a petal-type cylindrical weighted excitation cylinder, a dovetail anchor block, and a fixing pin. The two petals of the petal-type cylindrical weighted excitation cylinder are inserted into each other's square arc grooves and are positioned and locked by the dovetail anchor block and the fixing pin.

7. An application method of the coiled tubing stuck downhole cutting device according to claims 1-6, characterized in that: Step 1: Select a suitable size of coiled tubing string cutting and salvage tool, close the semi-closed gate and slip gate, release the injection head after the slip is loaded, and open the blowout preventer; Step 2: Install the anchoring and cutting mechanism, the recovery fixing mechanism and the split outer sleeve body, and after inspection, lift the cutting tool string into the blowout preventer; Step 3: Apply a certain upward load tension through the injection head to make the coiled tubing basically in a straight state, and open the semi-closed gate and the slip gate; Step 4: Release the installed cutting tool string and let it fall along the stuck coiled tubing by itself; Step 5: Close the semi-closed gate and the slip gate, release the injection head after the slip is loaded, and then open the blowout preventer; Step 6: Install the split-type cylindrical weighted excitation mechanism, and after inspection, lift the cutting tool string into the blowout preventer; Step 7: Apply a certain upward load tension through the injection head to make the coiled tubing basically in a straight state, open the semi-closed gate and the slip gate, and put the petal-type cylindrical weighted excitation mechanism into use to make it fall along the stuck coiled tubing by itself; Step 8: lift up the stuck coiled tubing string, tighten the cutting knife and cut the coiled tubing body; Step 9, pull off the stuck coiled tubing string, the cutter becomes free, and the split-type anchoring slip group is released; Step 10: lift out the stuck coiled tubing string and cutting tool string to complete the unblocking and salvaging work.

8. An application method of the coiled tubing stuck downhole cutting device according to claim 7, characterized in that: The downhole cutting device for the stuck point of the coiled tubing is of a split-petal design. It is lowered into the well without cutting the coiled tubing, and effectively stress cuts the coiled tubing under the external force of the excitation device. The coiled tubing is then lifted up to ensure that the coiled tubing breaks at the stuck point without plastic deformation. At the same time, the downhole cutting device for the stuck point of the coiled tubing can be lifted out of the wellhead along with the broken coiled tubing.

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