A soluble downhole choke

Abstract

The present application provides a soluble downhole choke, including a core tube assembly, a delivery assembly, a locking assembly, a soluble assembly, a sealing assembly and a throttling assembly, wherein the core tube assembly includes an upper core tube and a lower core tube, wherein the lower core tube is coaxially threadedly connected to the lower end of the upper core tube, the delivery assembly is coaxially sleeved on the upper end of the upper core tube, the locking assembly is coaxially sleeved on the upper core tube, the locking assembly has a first locking state and a second locking state, the soluble assembly is coaxially sleeved between the upper core tube and the locking assembly, the soluble assembly is provided with a soluble part, the sealing assembly is coaxially sleeved on the lower core tube and located below the locking assembly, and the throttling assembly is coaxially sleeved on the lower end of the lower core tube. When the present application needs to be removed, it only needs to add a preset solution to dissolve the soluble part, release the locking of the locking assembly and the wellbore, and the whole device falls due to its own weight, so as to realize the removal of the downhole throttling device, and there is no need to salvage, which is convenient for the next step of production, and is convenient and fast, and has strong practicality.

Description

Technical Field

[0001] The present application relates to the technical field of downhole chokes, and in particular to a soluble downhole choke. Background Art

[0002] In the process of natural gas extraction, downhole chokes are often installed in the wellbore of the gas well. The downhole choke can throttle through the downhole gas nozzle, reduce the natural gas pressure above the gas nozzle, realize throttling and pressure reduction in the wellbore, and convert pressure energy into kinetic energy, increase the fluid flow rate, so that the throttled fluid always maintains a critical flow state, reduce the impact of wellhead pressure fluctuations on the bottom of the well, and make full use of geothermal energy to prevent the formation of hydrates. After the throttling period, the staff needs to salvage the downhole choke from the wellbore for the next production.

[0003] In the actual throttling process, the downhole choke works for a long time in the underground and is in the complex environment of the underground for a long time. The choke slips often fall off, the rubber tube sticks to the well wall, and the fishing neck slips or breaks, which makes the choke difficult to salvage or even impossible to salvage, resulting in the inability to drain the gas well in time and the reduction of production. Based on this, the present application proposes a soluble downhole choke. Summary of the invention

[0004] The present application provides a soluble downhole throttle that can normally realize the throttling function. When it needs to be removed, it only needs to add a preset solution to dissolve the soluble part, so that the locking component changes from the second locking state to the first locking state, releases the locking of the locking component and the wellbore, and simultaneously releases the seal of the sealing component, so that the entire device falls due to its own weight, thereby realizing the removal of the downhole throttle without the need for salvage, which is convenient for the next step of production. It is fast and practical.

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

[0006] A soluble downhole throttle comprises a core tube assembly, a delivery assembly, a locking assembly, a soluble assembly, a sealing assembly and a throttling assembly, wherein the core tube assembly comprises an upper core tube and a lower core tube, wherein the lower core tube is coaxially threadedly connected to the lower end of the upper core tube, the delivery assembly is coaxially sleeved on the upper end of the upper core tube for delivery into a wellbore, the locking assembly is coaxially sleeved on the upper core tube, the locking assembly has a first locking state and a second locking state, and when the locking assembly changes from the first locking state to the second locking state, the locking assembly is locked with the wellbore, and the wellbore is locked. The soluble component is coaxially sleeved between the upper core tube and the locking component. The soluble component is provided with a soluble part, which can be dissolved in a preset solution. When the soluble part dissolves, the locking component can be changed from the second locking state to the first locking state. The sealing component is coaxially sleeved on the lower core tube and is located below the locking component. The sealing component can fit with the inner wall of the wellbore to achieve sealing or separate from the inner wall of the wellbore to achieve unsealing. The throttling component is coaxially sleeved on the lower end of the lower core tube and is used for throttling and reducing the pressure of the fluid in the gas well production tubing.

[0007] When in use, the staff connects the tool string formed by the wire rope, wire rope cap, weighted rod and mechanical vibrator to the delivery assembly, and can deliver the entire device into the wellbore, so that the locking assembly changes from the first locking state to the second locking state, so that the entire device is locked to the wellbore, the sealing assembly is sealed with the wellbore, and the throttling assembly can achieve throttling and pressure reduction. When removal is required, a preset solution is added to dissolve the soluble parts, so that the locking assembly changes from the second locking state to the first locking state, the locking of the locking assembly with the wellbore is released, and the sealing of the sealing assembly is released at the same time, so that the entire device falls due to its own weight, and the downhole throttle is removed.

[0008] Compared with the prior art, the soluble downhole throttle can normally realize the throttling function. When it needs to be removed, it only needs to add a preset solution to dissolve the soluble part, so that the locking component changes from the second locking state to the first locking state, releases the locking of the locking component and the wellbore, and releases the seal of the sealing component at the same time, so that the entire device falls due to its own weight, and the downhole throttle is removed without salvage, which is convenient for the next step of production. It is fast and practical.

[0009] In one embodiment of the present application, the delivery assembly includes a delivery head, a delivery pin and an upper joint, wherein the upper joint and the delivery head are coaxially arranged and connected via the delivery pin extending radially.

[0010] In one embodiment of the present application, the locking assembly includes a locking cylinder and a plurality of locking blocks, the locking cylinder is coaxially fixedly connected to the upper joint, the lower end of the locking cylinder is connected to the lower core tube by a first shear nail, the cylinder wall of the locking cylinder is evenly provided with a plurality of locking holes along the circumferential direction, and the plurality of the locking blocks are slidably connected in the locking holes in a one-to-one correspondence;

[0011] The clamping block is provided with a flange, and the flange is located in the clamping cylinder;

[0012] The first locking state is that there is a first gap between the flange and the inner wall of the locking tube and the locking block is not in contact with the inner wall of the wellbore, and the second locking state is that the locking block is in contact with the inner wall of the wellbore.

[0013] In one embodiment of the present application, the soluble component includes a retaining tube, an upper sliding sleeve, the soluble part, a lower sliding sleeve and a spring;

[0014] The retaining tube is coaxially sleeved between the upper core tube and the upper joint, and a liquid injection gap is provided between the retaining tube and the lower end of the upper joint. The retaining tube and the upper joint are connected by a second shear nail, and a pushing step is provided inwardly on the inner wall of the upper end of the retaining tube. When the second shear nail is cut off, the pushing step can push the upper core tube downward and cut off the first shear nail, and the retaining tube moves to the liquid injection gap, and the liquid injection gap is opened;

[0015] The upper sliding sleeve is coaxially sleeved on the upper core tube, the lower end of the upper sliding sleeve is provided with a first external thread, the soluble part is a sleeve structure, the upper end of the soluble part is provided with a first internal thread, the lower end of the soluble part is provided with a second internal thread, the upper end of the lower sliding sleeve is provided with a second external thread, the first internal thread cooperates with the first external thread, the second internal thread cooperates with the second external thread, the upper sliding sleeve is provided with an axial liquid injection through hole, the liquid injection through hole is opposite to the end face of the soluble part, the lower sliding sleeve is provided with a push slope, and the push slope abuts against the inner edge of the flange;

[0016] A support step is provided inwardly on the inner wall of the lower end of the locking cylinder, and the support step is located below the locking hole. The upper end of the spring abuts against the lower end of the lower sleeve, and the lower end of the spring abuts against the support step.

[0017] In one embodiment of the present application, the inner wall of the locking cylinder is provided with a first locking groove and a second locking groove, the lower end of the first locking groove forms a first slope, and the second locking groove is consistent in size with the first locking groove and is located below the first locking groove;

[0018] A plurality of first elastic arms are provided at the upper end of the upper sliding sleeve, and a first clamping protrusion is provided on the outer side of the first elastic arm, and the first clamping protrusion matches the size of the first clamping groove;

[0019] When the first locking protrusion cooperates with the first locking groove, the locking assembly is in a first locking state, and when the first locking protrusion cooperates with the second locking groove, the locking assembly is in a second locking state.

[0020] In one embodiment of the present application, the soluble part is made of aluminum-magnesium alloy, and the preset solution is a dilute hydrochloric acid solution.

[0021] In one embodiment of the present application, the inner circumferential wall and the outer circumferential wall of the soluble part are spray-painted.

[0022] In one embodiment of the present application, the sealing assembly includes an upper connecting sleeve, a retaining ring, a locking ring, a rubber sleeve, a central tube and a lower connecting sleeve;

[0023] The lower end of the lower connecting sleeve is provided with a connecting step inwardly, and the connecting step is threadedly screwed on the lower end of the lower core tube;

[0024] The central tube is coaxially sleeved on the lower core tube and located in the lower connecting sleeve, and the upper end of the central tube is provided with inverted teeth inclined downward;

[0025] The rubber sleeve is coaxially sleeved on the central tube, and the lower end of the rubber sleeve abuts against the lower connecting sleeve;

[0026] The retaining ring is coaxially sleeved on the central tube, the lower end of the retaining ring abuts against the rubber tube, and the upper connecting sleeve is fixed on the retaining ring;

[0027] The locking ring is coaxially threadedly connected to the retaining ring. An upwardly inclined stop thread is provided in the locking ring, and the stop thread cooperates with the inverted teeth.

[0028] In one embodiment of the present application, a third slot and a fourth slot are provided in the lower connecting sleeve, the upper end of the third slot forms a second slope, and the fourth slot has the same size as the third slot and is located below the third slot;

[0029] A plurality of second elastic arms are provided at the lower end of the central tube, and a second clamping protrusion is provided on the outer side of the second elastic arm, and the size of the second clamping protrusion matches that of the third clamping groove;

[0030] When the second clamping protrusion is matched with the fourth clamping groove, the lower connecting sleeve is in contact with the rubber sleeve, and the rubber sleeve is in a sealed state;

[0031] When the second clamping protrusion is engaged with the third clamping groove, the lower connecting sleeve is separated from the rubber cylinder, and the rubber cylinder is in an unsealed state.

[0032] In one embodiment of the present application, the throttling assembly includes a valve seat, a valve, a pressure cap and a sand control tube. The valve seat is coaxially connected to the lower core tube. The valve is coaxially arranged in the valve seat and fixedly connected by the pressure cap. The sand control tube is coaxially connected to the valve seat. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 A schematic diagram of the three-dimensional structure of a soluble downhole choke provided in one embodiment of the present application;

[0035] Figure 2 A schematic diagram of the cross-sectional structure of a soluble downhole choke provided in one embodiment of the present application before deployment;

[0036] Figure 3 for Figure 2 A partial enlarged view of the area above the dividing line A in the middle;

[0037] Figure 4 for Figure 2 A partial enlarged view of the area below the dividing line A in the middle;

[0038] Figure 5 A schematic cross-sectional structure diagram of a soluble downhole choke provided in an embodiment of the present application and achieving locking and sealing with a wellbore;

[0039] Figure 6 for Figure 5 A partial enlarged view of the area above the dividing line B in the middle;

[0040] Figure 7 for Figure 5 A partial enlarged view of the area below the dividing line B in the middle;

[0041] Figure 8 A schematic cross-sectional view of the structure of a soluble downhole choke and a wellbore unsealing device provided in one embodiment of the present application;

[0042] Fig. 9 for Figure 8 A partial enlarged view of the area above the middle C dividing line;

[0043] Fig.10 for Figure 8 A partial enlarged view of the area below the middle C dividing line;

[0044] Fig.11A schematic cross-sectional view of a soluble downhole choke and a wellbore released from locking provided by an embodiment of the present application;

[0045] Fig.12 for Fig.11 A partial enlarged view of the area above the middle D dividing line;

[0046] Fig.13 for Fig.11 A partial enlarged view of the area below the middle D dividing line;

[0047] Fig.14 A schematic cross-sectional view of a retaining tube used in a soluble downhole choke provided in one embodiment of the present application;

[0048] Fig.15 A schematic cross-sectional view of an upper sliding sleeve, a soluble part and a lower sliding sleeve used in a soluble downhole choke provided in one embodiment of the present application;

[0049] Fig.16 A schematic cross-sectional view of a fixing tube used in a soluble downhole choke provided in one embodiment of the present application;

[0050] Fig.17 A schematic diagram of the three-dimensional structure of a block used in a soluble downhole choke provided in one embodiment of the present application;

[0051] Fig.18 A schematic diagram of the three-dimensional structure of a central tube used in a soluble downhole choke provided in one embodiment of the present application;

[0052] Fig.19 A schematic cross-sectional structural diagram of a lower connecting sleeve used in a soluble downhole choke provided in one embodiment of the present application.

[0053] Reference numerals:

[0054] 100, core tube assembly; 110, upper core tube; 120, lower core tube; 200, delivery assembly; 210, delivery head; 220, delivery pin; 230, upper joint; 300, locking assembly; 310, locking cylinder; 311, locking hole; 312, supporting step; 313, first clamping groove; 314, second clamping groove; 320, clamping block; 321, flange; 330, first shear pin; 400, soluble assembly; 410, stop tube; 411, push step; 420, upper sliding sleeve; 421, injection through hole; 422, first elastic arm; 423, first clamping protrusion; 430, soluble Dissolving part; 440, lower sliding sleeve; 441, push ramp; 450, spring; 460, injection gap; 470, second shear nail; 500, sealing assembly; 510, upper connecting sleeve; 520, retaining ring; 530, locking ring; 540, rubber cylinder; 550, center tube; 551, inverted tooth; 552, second elastic arm; 553, second clamping protrusion; 560, lower connecting sleeve; 561, connecting step; 562, third clamping groove; 563, fourth clamping groove; 600, throttling assembly; 610, air nozzle seat; 620, air nozzle; 630, pressure cap; 640, sand control pipe; 700, soluble ball. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are 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 this field without creative work also fall within the scope of protection of the present application.

[0056] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are 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 device or element referred to 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.

[0057] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0058] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0059] The embodiment of the present application provides a soluble downhole choke, such as Figure 1 , Figure 2 , Figure 5 , Figure 8 and Fig.11 As shown, it includes a core tube assembly 100, a delivery assembly 200, a fixing assembly 300, a soluble assembly 400, a sealing assembly 500 and a throttling assembly 600, wherein the core tube assembly 100 includes an upper core tube 110 and a lower core tube 120, and the lower core tube 120 is coaxially threadedly connected to the lower end of the upper core tube 110 to form a long tube-shaped installation structure, which can be used to install and support other components.

[0060] like Figure 3 As shown, the delivery assembly 200 is coaxially sleeved on the upper end of the upper core tube 110 and is used to connect with the tool string, so as to deliver the entire soluble downhole choke into the wellbore, thereby achieving the delivery of the soluble downhole choke.

[0061] like Figure 3 As shown, the locking assembly 300 is coaxially sleeved on the upper core tube 110, and the locking assembly 300 has a first locking state and a second locking state. When the locking assembly 300 changes from the first locking state to the second locking state, the locking assembly 300 is locked with the wellbore, and the entire soluble downhole throttle can be locked on the wall of the wellbore, thereby realizing the locking installation of the soluble downhole throttle.

[0062] like Figure 3 As shown, the soluble component 400 is coaxially sleeved between the upper core tube 110 and the locking component 300, and the soluble component 400 is provided with a soluble part 430, which can be dissolved in a preset solution. Dissolution here means that the soluble part 430 can react chemically with the preset solution, so that the soluble part 430 gradually disappears. When it is necessary to remove, the soluble part 430 is dissolved by the preset solution, so that the locking component 300 changes from the second locking state to the first locking state, thereby releasing the locking of the locking component 300 and the wellbore.

[0063] like Figure 4 As shown, the sealing assembly 500 is coaxially sleeved on the lower core tube 120 and is located below the locking assembly 300. The sealing assembly 500 can be attached to or separated from the inner wall of the wellbore to achieve unsealing, thereby achieving sealing and unsealing.

[0064] like Figure 4As shown, the throttling assembly 600 is coaxially sleeved on the lower end of the lower core pipe 120, which can achieve throttling and pressure reduction of the fluid in the gas well production string.

[0065] When in use, the staff connects the tool string formed by the wire rope, wire rope cap, weighted rod and mechanical vibrator to the delivery assembly 200, and the entire device can be delivered into the wellbore. Then, the locking assembly 300 is changed from the first locking state to the second locking state, so that the entire device is locked to the wellbore, the sealing assembly 500 is sealed with the wellbore, and the throttling assembly 600 can achieve throttling and pressure reduction. When it is necessary to remove, a preset solution is added to dissolve the soluble part 430, so that the locking assembly 300 is changed from the second locking state to the first locking state, the locking of the locking assembly 300 with the wellbore is released, and the sealing of the sealing assembly 500 is released at the same time, so that the entire device falls due to its own weight, and the soluble downhole throttle is removed.

[0066] Compared with the prior art, the soluble downhole throttle can normally realize the throttling function. When it needs to be removed, it only needs to add a preset solution to dissolve the soluble part 430, so that the locking component 300 changes from the second locking state to the first locking state, releases the locking of the locking component 300 and the wellbore, and at the same time releases the seal of the sealing component 500, so that the entire device falls due to its own weight, thereby realizing the removal of the soluble downhole throttle without salvage, which is convenient for the next step of production, fast and practical.

[0067] In some embodiments, Figure 3 As shown, the delivery assembly 200 includes a delivery head 210, a delivery pin 220 and an upper joint 230. The delivery head 210 and the upper joint 230 are both rotatable structures. The upper joint 230 and the delivery head 210 are coaxially arranged and connected by the delivery pin 220 extending radially, so as to achieve the connection between the two. When the delivery pin 220 is cut off, the soluble downhole choke is released.

[0068] In some embodiments, Figure 3 As shown, the locking assembly 300 includes a locking cylinder 310 and a plurality of locking blocks 320. The locking cylinder 310 is coaxially fixedly connected to the upper joint 230. When fixed, the two can be fixedly connected by radial bolts.

[0069] like Figure 3 and Fig.16As shown, the lower end of the locking cylinder 310 is connected to the lower core tube 120 through a first shear nail 330, and the first shear nail 330 realizes the connection between the two in the radial direction. The cylinder wall of the locking cylinder 310 is evenly provided with a plurality of locking holes 311 along the circumferential direction, and a plurality of clamping blocks 320 are slidably connected in the locking holes 311 in a one-to-one correspondence, and the clamping blocks 320 can be radially close to or away from the center of the locking cylinder 310. In practice, the number of the clamping blocks 320 and the number of the locking holes 311 are equal, and generally can be set to four.

[0070] like Figure 3 and Fig.17 As shown, the block 320 is provided with a flange 321, and the flange 321 is located in the locking cylinder 310. The flange 321 is beyond the block 320, so as to prevent the block 320 from moving out of the locking hole 311 and avoid the block 320 from falling off.

[0071] The first locking state is that there is a first gap between the flange 321 and the inner wall of the locking tube 310 and the clamping block 320 does not abut against the inner wall of the wellbore, that is, the entire soluble downhole choke is not locked, and the soluble downhole choke can move up and down. The second locking state is that the clamping block 320 abuts against the inner wall of the wellbore, that is, the soluble downhole choke is locked with the inner wall of the wellbore, and the soluble downhole choke is fixed.

[0072] In some embodiments, Figure 3 As shown, the soluble component 400 includes a retaining tube 410, an upper sliding sleeve 420, a soluble part 430, a lower sliding sleeve 440 and a spring 450. The retaining tube 410 is coaxially sleeved between the upper core tube 110 and the upper joint 230. The retaining tube 410 is in contact with the upper part of the upper joint 230 and is connected by a second shear pin 470.

[0073] like Figure 5 , Fig. 9 and Fig.14 As shown, there is a liquid injection gap 460 between the retaining tube 410 and the lower end of the upper joint 230, and the inner wall of the upper end of the retaining tube 410 is provided with a pushing step 411 inwardly. When the second shear nail 470 is cut off, the retaining tube 410 can move downward, and the pushing step 411 can push the upper core tube 110 downward and cut the first shear nail 330. The upper end of the retaining tube 410 moves to the liquid injection gap 460, and the liquid injection gap 460 is opened, and liquid can be injected from the upper position of the retaining tube 410, thereby realizing the injection of the preset solution.

[0074] like Figure 3 and Fig.15As shown, the soluble part 430 is a sleeve structure, and the upper sleeve 420, the soluble part 430 and the lower sleeve 440 are all coaxially sleeved on the upper core tube 110. The lower end of the upper sleeve 420 is provided with a first external thread, the upper end of the soluble part 430 is provided with a first internal thread, the lower end of the soluble part 430 is provided with a second internal thread, and the upper end of the lower sleeve 440 is provided with a second external thread. The first internal thread cooperates with the first external thread, and the second internal thread cooperates with the second external thread, so as to realize the threaded connection of the upper sleeve 420, the soluble part 430 and the lower sleeve 440.

[0075] like Fig.15 As shown, the upper sleeve 420 is provided with an axial liquid injection hole 421, which is opposite to the end face of the soluble part 430, and the liquid injection hole 421 is connected to the liquid injection gap 460. When the liquid injection gap 460 is opened, the preset solution can reach the end face of the soluble part 430 through the liquid injection hole 421, thereby realizing the dissolution of the soluble part 430.

[0076] like Figure 3 , Figure 6 and Fig.15 As shown, the lower sleeve 440 is provided with a push slope 441, which abuts against the inner edge of the flange 321. When the lower sleeve 440 moves downward, the push slope 441 can push the flange 321, so that the blocking block 320 moves away from the center of the fixing tube 310 until it abuts against the wall of the wellbore.

[0077] like Figure 3 and Fig.16 As shown, the inner wall of the lower end of the locking cylinder 310 is provided with a supporting step 312 inwardly, and the supporting step 312 is located below the locking hole 311. The upper end of the spring 450 abuts against the lower end of the lower sleeve 440, and the lower end of the spring 450 abuts against the supporting step 312. The lower sleeve 440 is forced to move downward to squeeze the spring 450. When the external force of the lower sleeve 440 disappears, the spring 450 can rebound, and the lower sleeve 440 no longer supports the blocking block 320.

[0078] In some embodiments, Fig.16 As shown, the inner wall of the locking cylinder 310 is provided with a first locking groove 313 and a second locking groove 314, both of which are annular grooves, a first slope is formed at the lower end of the first locking groove 313, and the second locking groove 314 is consistent in size with the first locking groove 313 and is located below the first locking groove 313. In other words, the cross-sectional shapes of the first locking groove 313 and the second locking groove 314 are both substantially right-angled trapezoidal, and the sizes are the same.

[0079] like Fig.15As shown, a plurality of first elastic arms 422 are provided at the upper end of the upper sleeve 420. The first elastic arms 422 can be deformed to a certain extent. A first snap-in protrusion 423 is provided on the outer side of the first elastic arm 422. The first snap-in protrusion 423 matches the size of the first snap-in groove 313. The first snap-in protrusion 423 is also generally in a right-angled trapezoid and can be snap-fitted with the first snap-in groove 313 and the second snap-in groove 314.

[0080] like Figure 3 , Figure 6 , Fig.15 and Fig.16 As shown, when the first engaging protrusion 423 and the first engaging groove 313 cooperate, the engaging assembly 300 is in the first engaging state. When the upper sliding sleeve 420 moves downward, the first elastic arm 422 deforms inward, and the first engaging protrusion 423 can slide out of the first engaging groove 313 until the first engaging protrusion 423 reaches the second engaging groove 314, and the first engaging protrusion 423 and the second engaging groove 314 cooperate, and the engaging assembly 300 is in the second engaging state.

[0081] In some embodiments, the soluble part 430 is made of aluminum-magnesium alloy, and the preset solution is a dilute hydrochloric acid solution. The aluminum-magnesium alloy can react chemically with the dilute hydrochloric acid solution, thereby turning the solid soluble part 430 into a liquid solution, so that the soluble part 430 is dissolved.

[0082] In some embodiments, the inner circumferential wall and the outer circumferential wall of the soluble part 430 are sprayed with paint, and the spraying of paint can protect the soluble part 430, prevent the complex environment in the wellbore from corroding the soluble part 430, and ensure that the soluble part 430 does not fail for a long time. During implementation, the thickness of the sprayed paint can be controlled within 100 microns.

[0083] In some embodiments, Figure 4 and Fig.19 As shown, the sealing assembly 500 includes an upper connecting sleeve 510, a retaining ring 520, a locking ring 530, a rubber sleeve 540, a center tube 550 and a lower connecting sleeve 560. The lower end of the lower connecting sleeve 560 is provided with a connecting step 561 inwardly, the inner wall of the connecting step 561 is provided with an internal thread, the outer wall of the lower core tube 120 is provided with an external thread, and the connecting step 561 is threadedly screwed into the lower end of the lower core tube 120 to achieve a fixed connection between the two. At the same time, there is a gap between the upper part of the lower connecting sleeve 560 and the lower core tube 120.

[0084] like Figure 4 and Fig.18 As shown, the center tube 550 is coaxially sleeved on the lower core tube 120 and located in the lower connecting sleeve 560, that is, the center tube 550 is located in the gap between the lower connecting sleeve 560 and the lower core tube 120, and the upper end of the center tube 550 is provided with an inverted tooth 551 obliquely downward.

[0085] like Figure 4 As shown, the rubber cylinder 540 is coaxially sleeved on the central tube 550, and the lower end of the rubber cylinder 540 abuts against the lower connecting sleeve 560. There can be two rubber cylinders 540, which are arranged side by side along the axial direction. The rubber cylinder 540 can be deformed by being squeezed to change its radial size.

[0086] like Figure 4 As shown, the retaining ring 520 is coaxially sleeved on the central tube 550, the lower end of the retaining ring 520 abuts against the rubber tube 540, the upper connecting sleeve 510 is coaxially fixed on the retaining ring 520, the locking ring 530 is coaxially threadedly connected to the retaining ring 520, and the locking ring 530 is provided with an upward inclined stop thread, which cooperates with the inverted tooth 551.

[0087] like Figure 4 and Figure 7 As shown, when the upper connecting sleeve 510 moves downward, the rubber cylinder 540 can be squeezed by the retaining ring 520, and the rubber cylinder 540 is deformed, the radial dimension increases, and abuts against the wall of the wellbore to achieve sealing. At the same time, the locking ring 530 moves downward with the retaining ring 520 and the upper connecting sleeve 510, and the stop thread cooperates with the inverted teeth 551 to prevent the locking ring 530, the retaining ring 520 and the upper connecting sleeve 510 from moving upward, so that the rubber cylinder 540 can be squeezed and maintained in a sealed state.

[0088] In some embodiments, Fig.19 As shown, the lower connecting sleeve 560 is provided with a third clamping groove 562 and a fourth clamping groove 563, both of which are annular grooves, and the upper end of the third clamping groove 562 forms a second slope, and the fourth clamping groove 563 is consistent in size with the third clamping groove 562 and is located below the third clamping groove 562. In other words, the cross-sectional shapes of the third clamping groove 562 and the fourth clamping groove 563 are both substantially right-angled trapezoidal, and the sizes are the same.

[0089] like Fig.18 As shown, a plurality of second elastic arms 552 are provided at the lower end of the central tube 550. The second elastic arms 552 can be deformed to a certain extent. A second snap-in protrusion 553 is provided on the outer side of the second elastic arm 552. The second snap-in protrusion 553 matches the size of the third snap-in groove 562. The second snap-in protrusion 553 is also generally in a right-angled trapezoid and can cooperate with the third snap-in groove 562 and the fourth snap-in groove 563.

[0090] like Figure 7 and Fig.10As shown, when the second clamping protrusion 553 cooperates with the fourth clamping groove 563, the lower connecting sleeve 560 abuts against the rubber cylinder 540, and the rubber cylinder 540 is in a sealed state. When the lower connecting sleeve 560 moves downward, the second elastic arm 552 is deformed, and the second clamping protrusion 553 can slide out of the fourth clamping groove 563 until the second clamping protrusion 553 reaches the third clamping groove 562, and the second clamping protrusion 553 cooperates with the third clamping groove 562, the lower connecting sleeve 560 is separated from the rubber cylinder 540, and the rubber cylinder 540 is in an unsealed state.

[0091] In some embodiments, Figure 4 As shown, the throttling assembly 600 includes a nozzle seat 610, a nozzle 620, a pressure cap 630 and a sand control tube 640. The nozzle seat 610 is coaxially connected to the lower core tube 120, the nozzle 620 is coaxially arranged in the nozzle seat 610 and fixedly connected through the pressure cap 630, and the sand control tube 640 is coaxially connected to the nozzle seat 610. The sand control tube 640 can filter the well fluid, prevent impurities such as sand and gravel from entering the nozzle 620, prevent the nozzle 620 from being blocked, and ensure the normal use of the soluble downhole throttle.

[0092] The working principle of the soluble downhole choke is as follows:

[0093] like Figure 3 and Figure 6 As shown, the soluble downhole throttle is lowered into the oil pipe at a suitable position through the tool string, and a drilling stop effect is produced by rapidly lowering and then stopping suddenly. The upper sleeve 420, the soluble part 430 and the lower sleeve 440, which are composed of a whole, will continue to move downward relative to the upper core pipe 110 due to inertia, so that the first engaging protrusion 423 of the upper sleeve 420 moves from the first engaging groove 313 to the second engaging groove 314, and at the same time, the spring 450 is squeezed, so that the lower sleeve 440 can push the block 320, so that the block 320 is away from the center of the fixing tube 310, until the block 320 abuts against the inner wall of the wellbore to achieve fixing.

[0094] At the same time, Figure 4 and Figure 7 As shown, the whole composed of the upper connecting sleeve 510, the retaining ring 520 and the locking ring 530 will also move downward relative to the lower core pipe 120 due to inertia, and the retaining ring 520 will squeeze the rubber tube 540, causing the rubber tube 540 to deform, and the rubber tube 540 will abut against the inner wall of the wellbore to achieve sealing. The stop thread of the locking ring 530 and the inverted teeth 551 on the central tube 550 can maintain the deformation of the rubber tube 540, so that the rubber tube 540 remains in a sealed state. Continue to shock and lift the tool string, the delivery head 210 is forced to cut off the delivery pin 220, and the delivery head 210 is separated from the upper joint 230, and the entire soluble downhole throttle is released. The delivery head 210 can be taken out of the wellbore with the tool string, and the entire soluble downhole throttle enters a working state.

[0095] When it is necessary to remove the soluble downhole choke, Fig. 9 and Fig.10 As shown, a soluble ball 700 (made of the same material as the soluble part 430, i.e., also made of aluminum-magnesium alloy) is forcefully dropped downwardly onto the upper end of the retaining tube 410. The downward impact force of the soluble ball 700 can cause the retaining tube 410 to cut off the second shear pin 470 and move downward, and the upper end of the retaining tube 410 moves to the liquid injection gap 460, so that the liquid injection gap 460 is connected to the space at the upper end of the retaining tube 410. The pushing step 411 abuts against the upper core tube 110 and presses down the upper core tube 110 and the lower core tube 120. The lower core tube 120 cuts off the first shear nail 330 and drives the lower connecting sleeve 560 to move downward, so that the second clamping protrusion 553 of the center tube 550 moves from the third clamping groove 562 to the fourth clamping groove 563. The lower connecting sleeve 560 is separated from the rubber tube 540, the rubber tube 540 rebounds, the deformation disappears, the rubber tube 540 is separated from the wall of the wellbore, and the rubber tube 540 is unsealed.

[0096] like Fig. 9 As shown, about 5 cubic meters of 5% dilute hydrochloric acid solution is injected into the wellbore, and the dilute hydrochloric acid solution contacts the soluble ball 700 and reaches the soluble part 430 (i.e. Fig. 9 The path indicated by the arrow in the figure) reacts chemically with the aluminum-magnesium alloy.

[0097] like Fig.12 and Fig.13 As shown, after about 30 minutes, the soluble ball 700 and the soluble part 430 can be dissolved and disappear, and a gap will appear between the upper sliding sleeve 420 and the lower sliding sleeve 440. The lower sliding sleeve 440 moves upward due to the rebound effect of the spring 450, and the lower sliding sleeve 440 no longer pushes the block 320. The block 320 loses support and separates from the wall of the wellbore, and the fixation is released. The soluble downhole throttle falls to the bottom of the well under the action of its own weight, and the soluble downhole throttle is removed.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A soluble downhole choke, characterized in that: include: A core tube assembly, the core tube assembly comprising an upper core tube and a lower core tube, the lower core tube being coaxially threadedly connected to the lower end of the upper core tube; A delivery assembly, which is coaxially sleeved on the upper end of the upper core pipe and is used for delivery into the wellbore. The delivery assembly comprises a delivery head, a delivery pin and an upper joint. The upper joint and the delivery head are coaxially arranged and connected by the delivery pin extending in the radial direction. The locking assembly comprises a locking cylinder and a plurality of locking blocks, the locking cylinder being coaxially fixedly connected to the upper joint, the lower end of the locking cylinder being connected to the lower core tube by a first shear nail, the cylinder wall of the locking cylinder being evenly provided with a plurality of locking holes along the circumferential direction, the plurality of locking blocks being slidably connected in the locking holes in a one-to-one correspondence, the locking block being provided with a flange, the flange being located in the locking cylinder, the locking assembly having a first locking state and a second locking state, the first locking state being that the flange and the inner wall of the locking cylinder have a first gap and the locking block does not abut against the inner wall of the wellbore, the second locking state being that the locking block abuts against the inner wall of the wellbore, and when the locking assembly changes from the first locking state to the second locking state, the locking assembly is locked with the wellbore; A soluble component, the soluble component is coaxially sleeved between the upper core tube and the locking component, the soluble component is provided with a soluble part, the soluble part can be dissolved in a preset solution, when the soluble part is dissolved, the locking component can be changed from the second locking state to the first locking state; A sealing assembly, wherein the sealing assembly is coaxially sleeved on the lower core tube and is located below the locking assembly, and the sealing assembly can be attached to the inner wall of the wellbore to achieve sealing or separated from the inner wall of the wellbore to achieve unsealing; A throttling component is coaxially sleeved on the lower end of the lower core pipe and is used for throttling and reducing the pressure of the fluid in the gas well production pipe column.

2. The soluble downhole choke according to claim 1, characterized in that: The soluble component includes a retaining tube, an upper sliding sleeve, the soluble part, a lower sliding sleeve and a spring; The retaining tube is coaxially sleeved between the upper core tube and the upper joint, and a liquid injection gap is provided between the retaining tube and the lower end of the upper joint. The retaining tube and the upper joint are connected by a second shear nail, and a pushing step is provided inwardly on the inner wall of the upper end of the retaining tube. When the second shear nail is cut off, the pushing step can push the upper core tube downward and cut off the first shear nail, and the retaining tube moves to the liquid injection gap, and the liquid injection gap is opened; The upper sliding sleeve is coaxially sleeved on the upper core tube, the lower end of the upper sliding sleeve is provided with a first external thread, the soluble part is a sleeve structure, the upper end of the soluble part is provided with a first internal thread, the lower end of the soluble part is provided with a second internal thread, the upper end of the lower sliding sleeve is provided with a second external thread, the first internal thread cooperates with the first external thread, the second internal thread cooperates with the second external thread, the upper sliding sleeve is provided with an axial liquid injection through hole, the liquid injection through hole is opposite to the end face of the soluble part, the lower sliding sleeve is provided with a push slope, and the push slope abuts against the inner edge of the flange; A support step is provided inwardly on the inner wall of the lower end of the locking cylinder, and the support step is located below the locking hole. The upper end of the spring abuts against the lower end of the lower sleeve, and the lower end of the spring abuts against the support step.

3. The soluble downhole choke according to claim 2, characterized in that: The inner wall of the locking cylinder is provided with a first locking groove and a second locking groove, the lower end of the first locking groove forms a first slope, and the second locking groove is consistent in size with the first locking groove and is located below the first locking groove; A plurality of first elastic arms are disposed at the upper end of the upper sliding sleeve, and a first clamping protrusion is disposed on the outer side of the first elastic arm, and the first clamping protrusion matches the size of the first clamping groove; When the first locking protrusion cooperates with the first locking groove, the locking assembly is in a first locking state, and when the first locking protrusion cooperates with the second locking groove, the locking assembly is in a second locking state.

4. The soluble downhole choke according to claim 3, characterized in that: The soluble part is made of aluminum-magnesium alloy, and the preset solution is a dilute hydrochloric acid solution.

5. The soluble downhole choke according to claim 4, characterized in that: The inner circumferential wall and the outer circumferential wall of the soluble part are spray-painted.

6. The soluble downhole choke according to any one of claims 1 to 5, characterized in that: The sealing assembly comprises an upper connecting sleeve, a retaining ring, a locking ring, a rubber sleeve, a central tube and a lower connecting sleeve; The lower end of the lower connecting sleeve is provided with a connecting step inwardly, and the connecting step is threadedly screwed on the lower end of the lower core tube; The central tube is coaxially sleeved on the lower core tube and located in the lower connecting sleeve, and the upper end of the central tube is provided with inverted teeth inclined downward; The rubber sleeve is coaxially sleeved on the central tube, and the lower end of the rubber sleeve abuts against the lower connecting sleeve; The retaining ring is coaxially sleeved on the central tube, the lower end of the retaining ring abuts against the rubber tube, and the upper connecting sleeve is fixed on the retaining ring; The locking ring is coaxially threadedly connected to the retaining ring. An upwardly inclined stop thread is provided in the locking ring, and the stop thread cooperates with the inverted teeth.

7. The soluble downhole choke according to claim 6, characterized in that: The lower connecting sleeve is provided with a third slot and a fourth slot, the upper end of the third slot forms a second slope, and the fourth slot is consistent in size with the third slot and is located below the third slot; A plurality of second elastic arms are provided at the lower end of the central tube, and a second clamping protrusion is provided on the outer side of the second elastic arm, and the size of the second clamping protrusion matches that of the third clamping groove; When the second clamping protrusion is matched with the fourth clamping groove, the lower connecting sleeve is in contact with the rubber sleeve, and the rubber sleeve is in a sealed state; When the second clamping protrusion is engaged with the third clamping groove, the lower connecting sleeve is separated from the rubber cylinder, and the rubber cylinder is in an unsealed state.

8. The soluble downhole choke according to any one of claims 1 to 5, characterized in that: The throttling assembly includes a gas nozzle seat, a gas nozzle, a pressure cap and a sand control tube. The gas nozzle seat is coaxially connected to the lower core tube. The gas nozzle is coaxially arranged in the gas nozzle seat and fixedly connected through the pressure cap. The sand control tube is coaxially connected to the gas nozzle seat.

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