Milling device

Abstract

The invention belongs to the technical field of oil field downhole operation, and particularly relates to a casing milling device. The casing milling device comprises a first casing pipe, a second casing pipe, a barrel, a casing milling pipe, a casing milling shoe, a sealing unit, a packing unit and a liquid inlet unit, the casing milling device has a first state and a second state which can be switched, when the casing milling pipe is in the first state, the lower portion of the casing milling pipe is located in the barrel, and when the casing milling pipe is in the second state, the lower portion of the casing milling pipe is located in the barrel; the packing unit is used for packing a gap between the lower part of the milling pipe and the inner wall of the barrel body; the sealing unit, the packing unit, the milling pipe and the inner wall of the barrel body define a liquid inlet cavity; when the casing milling device is in the second state, the lower portion of the casing milling pipe is located in the cement cavity, the packing unit packs the gap between the lower portion of the casing milling pipe and the inner wall of the first casing pipe, and the sealing unit, the packing unit, the casing milling pipe, the inner wall of the barrel and the inner wall of the first casing pipe define a liquid inlet cavity; one end of the flow channel communicates with the liquid inlet cavity, and the other end communicates with the injection hole.

Description

Technical Field

[0001] The present application belongs to the technical field of oilfield downhole operations, and specifically relates to a sleeve milling device. Background Art Milling operation is one of the frequently used processes in oilfield downhole operations. It is a process method used to remove sand, cement, calcium carbonate crystals, etc. between the drill tool and the casing, and between the casings. Its main tools are milling shoes and milling pipes. The construction process of milling operation is to connect the milling shoe to the milling pipe by threading or welding, and then connect the milling pipe to the drill tool, and use the rotary table or power faucet to provide rotational power for construction. The casing replacement technology is a casing damage well repair process. In case of casing deformation, dislocation, rupture and leakage, the casing milling process is used to destroy the annular cement ring, then the damaged casing is removed, and then a new casing is lowered to complete the casing damage well repair. The indicators after repair are the same as those of the new well, and it can meet all the requirements of the later measures. It is the most thorough method for repairing casing damage wells. Before removing the casing, the cement ring in the annulus between the two layers of casing must be milled out by the casing milling operation, and then the next step of construction can be carried out. However, the conventional casing milling process is inefficient and takes a long time. Long-term casing milling operations may cause damage to the casing. Summary of the invention

[0002] In order to solve to a certain extent the technical problems that the current milling process has low efficiency, long milling time, and long-term milling operation may cause damage to the casing, the present application provides a milling device.

[0003] The present application provides a sleeve milling device, comprising:

[0004] A cylinder is arranged at the wellhead of the oil well, the cylinder is connected to the first casing, and the interior of the cylinder is communicated with the cement cavity; wherein the first casing is arranged in the oil well, the second casing is arranged in the first casing at intervals, and the cement ring is formed by the gap between the first casing and the second casing;

[0005] A sleeve milling pipe is movably arranged in the cylinder and can extend from the cylinder into the cement cavity;

[0006] A milling shoe is connected to the lower part of the milling tube, and a plurality of injection holes are arranged on the end surface of the milling shoe;

[0007] A sealing unit, used for sealing the gap between the upper portion of the sleeve milling tube and the inner wall of the cylinder;

[0008] A sealing unit is used to seal the gap between the lower part of the sleeve milling tube and the inner wall of the barrel or the inner wall of the first sleeve, wherein the sealing unit, the sealing unit, the sleeve milling tube and the inner wall of the barrel form a liquid inlet cavity, or the sealing unit, the sealing unit, the sleeve milling tube, the inner wall of the barrel and the inner wall of the first sleeve form the liquid inlet cavity, and the sealing unit has a flow channel, and the cross section of the flow channel becomes narrower from top to bottom;

[0009] The liquid inlet unit is arranged between the sealing unit and the isolation unit and is connected with the liquid inlet cavity to pass the circulating liquid into the flow channel and then spray it out from the spray hole to form a high-speed water flow to break the cement ring in the cement cavity.

[0010] In some embodiments, the milling shoe includes a milling shoe body and a plurality of alloy blocks, wherein the plurality of alloy blocks are arranged at circumferential intervals along the end surface of the milling shoe body, and the injection hole is arranged on the end surface of the milling shoe body and located between two adjacent alloy blocks.

[0011] In some embodiments, a liquid channel is provided inside the sleeve milling shoe body, one end of the liquid channel is connected to the flow channel, and the other end is connected to the injection hole, and the lower part of the liquid channel is conveniently inclined toward the edge of the sleeve milling shoe body.

[0012] In some embodiments, the sealing unit includes a rubber cylinder and an upper pressure cover, the rubber cylinder is arranged in the gap between the upper part of the sleeve milling tube and the inner wall of the cylinder, the upper pressure cover is arranged at the top of the main body and is sleeved in the main body, the sleeve milling tube is passed through the upper pressure cover, and the upper pressure cover is extruded with the rubber cylinder.

[0013] In some embodiments, the rubber cartridge includes a rubber cartridge body and a rubber cartridge seat, wherein the rubber cartridge seat is supported and arranged on the rubber cartridge body, the rubber cartridge seat is arranged close to the inner wall of the cylinder, and the rubber cartridge body is arranged between the sleeve milling tube and the rubber cartridge seat.

[0014] In some embodiments, the sealing unit further includes a sealing ring, and the sealing ring is disposed between the rubber cylinder and the inner wall of the cylinder.

[0015] In some embodiments, the device further comprises a bearing, and the bearing is disposed between the sleeve milling tube and the inner wall of the cylinder.

[0016] In some embodiments, the isolation unit is connected to the milling shoe, one side of the isolation unit forms the flow channel with the lower portion of the milling tube, and the other side is pressed against the inner wall of the cylinder or the inner wall of the surface oil pipe.

[0017] In some embodiments, the isolation unit is a leather cup packer, and the leather cup of the isolation unit is pressed tightly against the inner wall of the cylinder or the inner wall of the surface oil pipe.

[0018] In some embodiments, the cylinder includes an outer shell, a connecting sleeve, and a casing coupling that are sequentially connected from top to bottom, the sealing unit is disposed in the outer shell, and the casing coupling is connected to the first casing.

[0019] According to the sleeve milling device provided by one or more embodiments of the present application, since the sealing unit seals the gap between the upper part of the sleeve milling tube and the inner wall of the cylinder, that is, the liquid inlet chamber is not connected to the atmosphere, when the liquid inlet unit passes the circulating liquid into the liquid inlet chamber, the circulating liquid will enter the flow channel. Since the cross-section of the flow channel becomes narrower from top to bottom, the pressure of the liquid inlet chamber will increase in the process of the circulating liquid flowing through the flow channel. Under the action of pressure, the circulating liquid will be ejected at high speed through the injection hole to form a high-speed water flow, thereby destroying the cement ring. That is, the high-speed water flow and the sleeve milling shoe work together to break the cement ring, which can improve the crushing efficiency of the cement ring, change the traditional sleeve milling that only relies on the sleeve milling shoe grinding and has low efficiency, to a certain extent avoid the situation where long-term sleeve milling operation causes damage to the casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram is shown when the sleeve milling device is in the first state.

[0021] Figure 2 Shows Figure 1 A partial enlarged view of the .

[0022] Figure 3 A schematic structural diagram is shown when the sleeve milling device is in the second state.

[0023] Figure 4 Shows Figure 1 Schematic diagram of the structure of the middle set milling shoe end face.

[0024] Description of reference numerals:

[0025] 100-sleeve milling device, 110-first sleeve, 120-second sleeve, 130-cylinder, 131-liquid inlet chamber, 132-housing, 133-connecting sleeve, 134-sleeve coupling, 135-step structure, 140-sleeve milling tube, 150-sleeve milling shoe, 151-sleeve milling shoe body, 152-alloy block, 153-injection hole, 154-liquid channel, 160-sealing unit, 161-rubber cylinder, 1611-rubber cylinder body, 1612-rubber cylinder seat, 1613-rubber cylinder pressure cover, 162-upper pressure cover, 163-sealing ring, 170-sealing unit, 171-flow channel, 180-liquid inlet unit, 190-bearing, 191-first bearing, 192-second bearing. DETAILED DESCRIPTION

[0026] In order to make the technical personnel in the technical field to which the present application belongs to understand the present application more clearly, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0027] Combination Figure 1-Figure 3 A milling device 100 provided in an embodiment of the present application can form a high-speed water flow to work together with a milling shoe 150 to break the cement ring during the milling operation, thereby improving the crushing efficiency of the cement ring, reducing the milling time, and to a certain extent avoiding long-term milling operations and damage to the casing.

[0028] The sleeve milling device 100 provided in the embodiment of the present application includes a first casing 110, a second casing 120, a barrel 130, a sleeve milling tube 140, a sleeve milling shoe 150, a sealing unit 160, a sealing unit 170 and a liquid inlet unit 180. The first casing 110 is arranged in the oil well, the second casing 120 is arranged in the first casing 110 at intervals, and a cement cavity is formed between the first casing 110 and the second casing 120, and a cement ring is formed in the cement cavity; the barrel 130 is arranged at the wellhead of the oil well, the barrel 130 is connected to the first casing 110, and the interior of the barrel 130 is connected to the cement cavity; the sleeve milling tube 140 is movably inserted into the barrel 130 and can be extended into the cement cavity from the barrel 130; the sleeve milling shoe 150 is arranged in communication with the lower part of the sleeve milling tube 140, and a plurality of injection holes 153 are arranged on the end face of the sleeve milling shoe 150; the sealing unit 160 is used to seal the gap between the upper part of the sleeve milling tube 140 and the inner wall of the cylinder 130; the sealing unit 170 is used to seal the gap between the lower part of the sleeve milling tube 140 and the inner wall of the cylinder 130 or the inner wall of the first sleeve 110. The sealing unit 160, the sealing unit 170, the sleeve milling tube 140 and the inner wall of the cylinder 130 form a liquid inlet cavity 131, or the sealing unit 160, the sealing unit 170, the sleeve milling tube 140, the inner wall of the cylinder 130 and the inner wall of the first sleeve 110 form a liquid inlet cavity 131. The sealing unit 170 has a flow channel 171, and the cross-section of the flow channel 171 becomes narrower from top to bottom.

[0029] The sleeve milling device 100 has a switchable first state and a second state. When the sleeve milling tube 140 is in the first state, the lower part of the sleeve milling tube 140 is located in the cylinder 130, and the sealing unit 170 seals the gap between the lower part of the sleeve milling tube 140 and the inner wall of the cylinder 130. The sealing unit 160, the sealing unit 170, the sleeve milling tube 140 and the inner wall of the cylinder 130 form a liquid inlet cavity 131; when the sleeve milling device 100 is in the second state, the lower part of the sleeve milling tube 140 is located in the cement cavity, and the sealing unit 170 seals the lower part of the sleeve milling tube 140. The gap between the sealing unit 160 and the inner wall of the first casing 110, the sealing unit 160, the isolation unit 170, the casing milling tube 140, the inner wall of the cylinder 130 and the inner wall of the first casing 110 form a liquid inlet chamber 131; one end of the flow channel 171 is connected to the liquid inlet chamber 131, and the other end is connected to the injection hole 153; the liquid inlet unit 180 is arranged between the sealing unit 160 and the isolation unit 170, and is connected to the liquid inlet chamber 131, so as to pass the circulating liquid into the flow channel 171, and then spray it out from the injection hole 153 to form a high-speed water flow to break the cement ring.

[0030] During the drilling process, when the drill bit reaches a certain depth, a steel casing is placed in the well, and then cement is injected into the annular space between the casing and the wellbore. After the cement solidifies, it can prevent the well wall from collapsing. Then a smaller drill bit is replaced and inserted into the casing to continue drilling. When the well wall is unstable again after drilling to a certain depth, the drill string is lifted, and a smaller casing is placed in the original casing to extend downward, and then cement is injected between the casing and the wellbore, and so on. That is, almost all oil wells will have more than two layers of casing, and the number of casings can be determined according to the well depth and geological conditions. The casings are surface casing, technical casing, oil layer casing, tail pipe, etc. from large to small. The first casing 110 and the second casing 120 in the embodiment of the present application can be any two adjacent casings. Of course, the size of the second casing 120 is smaller than the first casing 110.

[0031] The barrel 130 is arranged on the ground and is arranged corresponding to the wellhead. One end of the milling tube 140 is arranged outside the barrel 130 (not shown in the figure) and connected to the drilling tool. The other end is inserted into the barrel 130 and can extend downward into the cement cavity. That is, when the milling tube 140 is located in the cement cavity, the milling tube 140 is arranged between the first casing 110 and the second casing 120. Of course, as the oil well is drilled deeper and deeper, the milling tube 140 can continue to extend downward to adapt to the depth of the oil well. The end surface of the milling shoe 150 is provided with milling teeth. The milling tube 140 can provide rotational power through a power faucet or a turntable to drive the milling shoe 150 to rotate, so that the milling teeth on the milling shoe 150 can break the cement ring by rotation.

[0032] The sealing unit 160 is used to seal the gap between the upper part of the milling tube 140 and the inner wall of the cylinder 130, and the sealing unit 170 is used to seal the gap between the lower part of the milling tube 140 and the inner wall of the cylinder 130 or the inner wall of the first casing 110. It should be noted that the "upper part of the milling tube 140" here refers to the upper part of the milling tube 140 located in the cylinder 130, and the "lower part of the milling tube 140" refers to the part of the milling tube 140 close to the milling shoe 150.

[0033] When the well with cement returned to the ground is milled, the milling pipe 140 is in the first state, the lower part of the milling pipe 140 is located in the cylinder 130, the isolation unit 170 isolates the gap between the lower part of the milling pipe 140 and the inner wall of the cylinder 130, the sealing unit 160, the isolation unit 170, the milling pipe 140 and the inner wall of the cylinder 130 form a liquid inlet chamber 131, and after the liquid inlet unit 180 passes the circulating fluid into the liquid inlet chamber 131, the circulating fluid will enter the flow channel 171. Since the cross-section of the flow channel 171 gradually narrows from top to bottom, the pressure of the liquid inlet chamber 131 will increase during the circulation of the circulating fluid through the flow channel 171. Under the action of the pressure, the circulating fluid will be ejected at high speed through the injection hole 153 to form a high-speed water flow, thereby destroying the cement ring returned to the ground. As the cement ring returned to the ground is destroyed, the lower part of the milling pipe 140 gradually extends from the cylinder 130 into the water In the mud cavity, the casing milling tube 140 is in the second state at this time, and the isolation unit 170 isolates the gap between the lower part of the casing milling tube 140 and the inner wall of the first casing 110. The sealing unit 160, the isolation unit 170, the casing milling tube 140, the inner wall of the cylinder 130 and the inner wall of the first casing 110 surround the liquid inlet cavity 131. Of course, the inner wall of the first casing 110 is connected and arranged below the inner wall of the cylinder 130. Similarly, after the liquid inlet unit 180 passes the circulating fluid into the liquid inlet cavity 131, the circulating fluid will enter the flow channel 171. Since the cross-section of the flow channel 171 becomes narrower from top to bottom, the pressure of the liquid inlet cavity 131 will increase during the circulation of the circulating fluid through the flow channel 171. Under the action of pressure, the circulating fluid will be ejected at high speed through the injection hole 153 to form a high-speed water flow, thereby breaking the cement ring in the well. As the casing milling depth deepens, the extension length of the casing milling tube 140 becomes longer and longer. That is, on the basis of the rotation of the milling shoe 150 to destroy the cement ring, a high-speed water flow is added to destroy the cement ring, so that the high-speed water flow and the milling shoe 150 work together to break the cement ring, thereby improving the crushing efficiency of the cement ring and avoiding long-term milling operations to a certain extent, which may cause damage to the casing.

[0034] In some embodiments, the liquid inlet unit 180 is used to provide circulating fluid. After the cement sheath is broken, it needs to flow back to the ground along with the circulating fluid. The liquid inlet unit 180 includes a bypass and a pumping device. The pumping device pumps the circulating fluid from the bypass into the liquid inlet chamber 131 .

[0035] It should be noted that the crushed cement is returned along with the circulating fluid through the inside of the casing milling pipe 140 .

[0036] It is worth mentioning that the setting of the sealing unit 160 can not only isolate the liquid inlet chamber 131 from the atmosphere, forming a high-pressure liquid inlet chamber 131, so that the circulating liquid can be sprayed out at high speed through the spray hole under the action of pressure when passing through the flow channel 171 whose cross-section changes from wide to narrow, but also can prevent the circulating liquid from flowing out from the upper channel between the casing milling tube 140 and the cylinder 130 to a certain extent, thereby ensuring that the circulating liquid and the crushed cement enter the casing milling tube 140 and flow back to the ground.

[0037] In some embodiments, in combination Figure 3-Figure 4 The milling shoe 150 includes a milling shoe 150 body and a plurality of alloy blocks 152 . The plurality of alloy blocks 152 are arranged at intervals along the circumferential direction of the end surface of the milling shoe 150 body. The injection hole 153 is arranged on the end surface of the milling shoe 150 body and is located between two adjacent alloy blocks 152 .

[0038] The alloy block 152 is a cemented carbide block 152 to enhance the wear resistance of the sleeve milling shoe 150. Specifically, the alloy block 152 can be cobalt-containing tungsten carbide. A groove is formed between two adjacent alloy blocks 152, and the injection hole 153 is set in the groove. Since the injection hole 153 is located between two adjacent alloy blocks 152, the setting of the injection hole 153 does not interfere with the alloy block 152. The number of injection holes 153 can be set according to actual needs. The injection hole 153 can be set in each groove, or the injection hole 153 can be set at intervals of one groove, and there is no limitation on this.

[0039] It is worth mentioning that a plurality of injection holes 153 can be arranged at equal intervals along the end surface of the main body of the milling shoe 150, so that the annular cement ring can be sprayed evenly, thereby improving the hydraulic mud breaking efficiency and the cleanliness of the milling surface.

[0040] In some embodiments, a liquid channel 154 is provided inside the main body of the milling shoe 150 , one end of the liquid channel 154 is connected to the flow channel 171 , and the other end is connected to the injection hole 153 , and the lower part of the liquid channel 154 is conveniently inclined toward the edge of the main body of the milling shoe 150 .

[0041] Since the liquid channel 154 is tilted, the water jetted from the jet hole 153 is also tilted. The tilted design of the liquid channel 154 can match the alloy arrangement of the milling shoe 150, improve the smoothness of the milling shoe 150's rotation and milling, and is more conducive to carrying cement chips and cooling the milling shoe 150.

[0042] In some embodiments, the sealing unit 160 includes a rubber cylinder 161 and an upper pressure cover 162. The rubber cylinder 161 is arranged in the gap between the upper part of the sleeve milling tube 140 and the inner wall of the cylinder body 130. The upper pressure cover 162 is arranged at the top of the main body and is sleeved in the main body. The sleeve milling tube 140 is passed through the upper pressure cover 162, and the upper pressure cover 162 and the rubber cylinder 161 are extruded.

[0043] The rubber cylinder 161 is made of a flexible material and is disposed in the gap between the upper portion of the sleeve milling tube 140 and the inner wall of the cylinder body 130 . The upper pressure cover 162 squeezes the rubber cylinder 161 , thereby deforming the rubber cylinder 161 and interferingly disposing it in the gap to achieve a better sealing effect.

[0044] The lower end of the upper pressure cover 162 is provided with a thread to be threadedly connected to the cylinder 130 . After the upper pressure cover 162 is fastened to the cylinder 130 by the thread, the rubber sleeve 161 is squeezed.

[0045] Specifically, the rubber cartridge 161 includes a rubber cartridge body 1611 and a rubber cartridge seat 1612 . The rubber cartridge seat 1612 is supported and disposed on the rubber cartridge body 1611 . The rubber cartridge seat 1612 is disposed close to the inner wall of the cylinder body 130 . The rubber cartridge body 1611 is disposed between the sleeve milling tube 140 and the rubber cartridge seat 1612 .

[0046] The function of the rubber cylinder seat 1612 is to support the rubber cylinder body 1611, so that the rubber cylinder body 1611 is not damaged under a certain pressure. The fitting surface of the rubber cylinder seat 1612 and the rubber cylinder body 1611 can be an inclined surface, which can make the rubber cylinder seat 1612 and the rubber cylinder body 1611 fit more closely to ensure a better sealing effect.

[0047] In some embodiments, the sealing unit 160 further includes a sealing ring 163 , which is disposed between the rubber sleeve 161 and the inner wall of the cylinder body 130 .

[0048] The sealing ring 163 is disposed between the rubber cylinder 161 and the inner wall of the cylinder 130, thereby further improving the sealing effect between the sleeve milling tube 140 and the inner wall of the cylinder 130. Specifically, the sealing ring 163 is disposed between the rubber cylinder seat 1612 and the inner wall of the cylinder 130.

[0049] In some embodiments, the device further includes a bearing 190 , which is disposed between the sleeve milling tube 140 and the inner wall of the cylinder 130 .

[0050] As mentioned above, the milling tube 140 will rotate under the action of the power faucet or the turntable to drive the milling shoe 150 to rotate. Therefore, in order to reduce the friction of the milling tube 140 during rotation and avoid damage to the milling tube 140 to a certain extent, a bearing 190 is set between the milling tube 140 and the inner wall of the cylinder 130.

[0051] Specifically, the bearing 190 can be a thrust ball bearing 190. Two bearings 190 can be provided, namely a first bearing 191 and a second bearing 192. The first bearing 191 is provided between the upper pressure cover 162 and the rubber cylinder 161, that is, the upper pressure cover 162 squeezes the rubber cylinder 161 through the bearing 190, and the second bearing 192 is provided below the rubber cylinder 161, that is, the rubber cylinder 161 is provided between the first bearing 191 and the second bearing 192, and a step structure 135 is provided on the inner wall of the cylinder 130, and the second bearing 192 is clamped on the step structure 135, that is, when the upper pressure cover 162 is in the process of passing through the threaded knob on the cylinder 130, pressure is applied to the first bearing 191, and under the support of the second bearing 192, the rubber cylinder 161 is squeezed, so that the rubber cylinder 161 is interference-set in the gap to achieve a better sealing effect.

[0052] Of course, multiple bearings 190 may be provided, and this is not limited.

[0053] In addition, a rubber cylinder pressure cover 1613 may be disposed between the bearing 190 and the rubber cylinder 161 , and its main function is to protect the rubber cylinder 161 and prevent the bearing 190 from rotating and the operation of tightening the upper pressure cover 162 from damaging the rubber cylinder 161 .

[0054] In some embodiments, the isolation unit 170 is connected to the milling shoe 150, a flow channel 171 is formed between one side of the isolation unit 170 and the lower part of the milling tube 140, and the other side is pressed against the inner wall of the cylinder 130 or the inner wall of the surface oil pipe.

[0055] Specifically, the packing unit 170 may be a cup packer, the cup of which is pressed against the inner wall of the barrel 130 or the inner wall of the surface oil pipe, and the cup packer and the milling shoe 150 may be connected together through a steel ball, and the cup packer remains stationary during the rotation of the milling shoe 150. When the circulating fluid enters the flow channel 171, the flow channel 171 becomes narrower, and the pressure in the liquid inlet cavity 131 increases. Under the action of the pressure, the cup of the cup packer will be pressed against the inner wall of the casing to achieve sealing.

[0056] In some embodiments, the cylinder 130 includes an outer shell 132, a connecting sleeve 133 and a casing coupling 134 connected in sequence from top to bottom, the sealing unit 160 is disposed in the outer shell 132, the connecting sleeve 133 is used to connect the outer shell 132 and the casing coupling 134, and the casing coupling 134 is connected to the first casing 110.

[0057] In some embodiments, sand can be added to the circulating fluid. When the sand content is 5%, the flow rate at the injection hole can reach 80-100 m / S, the crushing distance is greater than 20 mm, and the auxiliary crushing effect is obvious.

[0058] Next, the method of using the sleeve milling device 100 is described:

[0059] Assemble the barrel 130, the milling pipe 140 and the milling shoe 150 on the ground, weld the bottom of the barrel 130 to the first casing 110 of the outer layer of the cement ring of the construction well, and test the pressure to 15MPa; after the milling shoe 150 reaches the cement surface, prepare for milling construction, and the cement truck pumps circulating fluid into the bypass. Under the action of pressure, the leather cup packer is tightly attached to the inner wall of the first casing 110 to form a closed space. At this time, the circulating fluid enters the flow channel 171 from the closed space. Since the cross-section of the flow channel 171 changes from wide to narrow, when the circulating fluid flows through a narrower part, the pressure of the liquid inlet chamber 131 increases. Under the action of pressure, the circulating fluid entering the liquid channel 154 is ejected at high speed from the injection hole 153 on the end face of the milling shoe 150. Operate the power faucet to rotate and start milling the cement ring, so that the high-speed water flow and the milling shoe 150 can achieve double-action crushing of the cement ring. The rotation speed can be adjusted according to the actual situation on site, and the displacement of the circulating pump can be gradually adjusted to increase the pressure of the injection hole 153, and the maximum pressure is controlled within 15MPa. After the milling of one milling tube 140 is completed, another milling tube 140 is connected to continue milling, and the above actions are repeated until the milling depth is reached.

[0060] The sleeve milling device 100 provided in the embodiment of the present application has a sealing unit 160 that seals the gap between the upper part of the sleeve milling tube 140 and the inner wall of the cylinder 130, that is, the liquid inlet chamber 131 is not connected to the atmosphere. When the liquid inlet unit 180 passes the circulating liquid into the liquid inlet chamber 131, the circulating liquid will enter the flow channel 171. Since the cross-section of the flow channel 171 gradually narrows from top to bottom, the pressure of the liquid inlet chamber 131 will increase in the process of the circulating liquid flowing through the flow channel 171. Under the action of pressure, the circulating liquid will be ejected at high speed through the injection hole 153 to form a high-speed water flow, thereby destroying the cement ring. That is, the high-speed water flow and the sleeve milling shoe 150 work together to break the cement ring, which can improve the crushing efficiency of the cement ring and avoid damage to the casing due to long-term sleeve milling operation to a certain extent.

[0061] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0062] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise" and "counterclockwise" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0063] In this application, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0064] In addition, the descriptions of "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0065] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A sleeve milling device, characterized in that: include: A cylinder is arranged at the wellhead of the oil well, the cylinder is connected to the first casing, and the interior of the cylinder is communicated with the cement cavity; wherein the first casing is arranged in the oil well, the second casing is arranged in the first casing at intervals, and the cement ring is formed by the gap between the first casing and the second casing; A sleeve milling pipe is movably arranged in the cylinder and can extend from the cylinder into the cement cavity; A milling shoe is connected to the lower part of the milling tube, and a plurality of injection holes are arranged on the end surface of the milling shoe; A sealing unit, used for sealing the gap between the upper portion of the sleeve milling tube and the inner wall of the cylinder; A sealing unit is used to seal the gap between the lower part of the sleeve milling tube and the inner wall of the barrel or the inner wall of the first sleeve, wherein the sealing unit, the sealing unit, the sleeve milling tube and the inner wall of the barrel form a liquid inlet cavity, or the sealing unit, the sealing unit, the sleeve milling tube, the inner wall of the barrel and the inner wall of the first sleeve form the liquid inlet cavity, and the sealing unit has a flow channel, and the cross section of the flow channel becomes narrower from top to bottom; The liquid inlet unit is arranged between the sealing unit and the isolation unit and is connected with the liquid inlet cavity to pass the circulating liquid into the flow channel and then spray it out from the spray hole to form a high-speed water flow to break the cement ring in the cement cavity.

2. The sleeve milling device according to claim 1, characterized in that: The milling shoe comprises a milling shoe body and a plurality of alloy blocks, wherein the plurality of alloy blocks are arranged at intervals along the circumferential direction of the end surface of the milling shoe body, and the injection hole is arranged on the end surface of the milling shoe body and located between two adjacent alloy blocks.

3. The sleeve milling device according to claim 1, characterized in that: A liquid channel is provided inside the sleeve milling shoe body, one end of the liquid channel is communicated with the flow channel, and the other end is communicated with the injection hole, and the lower part of the liquid channel is conveniently inclined toward the edge of the sleeve milling shoe body.

4. The sleeve milling device according to any one of claims 1 to 3, characterized in that: The sealing unit includes a rubber cylinder and an upper pressure cover. The rubber cylinder is arranged in the gap between the upper part of the sleeve milling tube and the inner wall of the cylinder. The upper pressure cover is arranged on the top of the main body and is sleeved in the main body. The sleeve milling tube is passed through the upper pressure cover, and the upper pressure cover is extruded with the rubber cylinder.

5. The sleeve milling device according to claim 4, characterized in that: The rubber cartridge comprises a rubber cartridge body and a rubber cartridge seat, wherein the rubber cartridge seat is supported and arranged on the rubber cartridge body, the rubber cartridge seat is arranged close to the inner wall of the cylinder, and the rubber cartridge body is arranged between the sleeve milling tube and the rubber cartridge seat.

6. The sleeve milling device according to claim 4, characterized in that: The sealing unit further comprises a sealing ring, and the sealing ring is arranged between the rubber cylinder and the inner wall of the cylinder.

7. The sleeve milling device according to any one of claims 1 to 3, characterized in that: The device also includes a bearing, which is arranged between the sleeve milling tube and the inner wall of the cylinder.

8. The sleeve milling device according to any one of claims 1 to 3, characterized in that: The sealing unit is connected to the sleeve milling shoe, one side of the sealing unit forms the flow channel with the lower part of the sleeve milling tube, and the other side is pressed against the inner wall of the cylinder or the inner wall of the surface oil pipe.

9. The sleeve milling device according to claim 8, characterized in that: The sealing unit is a leather cup packer, and the leather cup of the sealing unit is pressed tightly against the inner wall of the cylinder or the inner wall of the surface oil pipe.

10. The sleeve milling device according to claim 1, characterized in that: The cylinder comprises an outer shell, a connecting sleeve and a sleeve coupling which are sequentially connected from top to bottom; the sealing unit is arranged in the outer shell, and the sleeve coupling is connected to the first sleeve.

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