Infinite-stage sliding sleeve and using method

Abstract

The invention provides an infinite-stage sliding sleeve and a using method, the sliding sleeve comprises a sliding sleeve main body with an abutting part, an inner sleeve, a guide sleeve connected with the inner sleeve and a ball seat, the ball seat can be connected with the inner sleeve and drive the inner sleeve and the guide sleeve to move together in the moving process in the sliding sleeve, so that the end part of the guide sleeve is in contact with the abutting part, and the inner sleeve is in contact with the abutting part. The abutting part can further extrude the end of the guide sleeve so that the end of the guide sleeve can be shrunk inwards till the inner diameter of the end of the guide sleeve is smaller than the outer diameter of the portion, close to the end of the guide sleeve, of the ball seat, and the ball seat is made of soluble alloy materials. The ball seat can overcome the defects that an existing insoluble ball seat is not in place in pumping, clamps a pipe column and the like, meanwhile, the bearing capacity of the ball seat is greatly improved, and the ball seat has higher reliability and adaptability.

Description

Technical Field

[0001] The present invention relates to the technical field of oil drilling, and specifically, to an infinitely variable sliding sleeve and a usage method thereof. Background Art

[0002] With the continuous deepening of oil and gas resource production and exploitation, the number of unconventional oil and gas wells with low porosity and low permeability is increasing, which also makes the difficulty of oilfield production and exploitation gradually increase. Tight oil and gas have become increasingly prominent in the energy strategic deployment. However, affected by many adverse factors such as dense reservoir spaces, strong heterogeneity, and poor oil and gas saturation, the exploitation is difficult and more stages are required to recover reserves and release production capacity. In the actual oilfield exploitation process, the full use of the horizontal well staged fracturing technology has effectively increased the oilfield production, which is a very widely used production enhancement means in the current oilfield. In recent years, the multi-stage fracturing of horizontal wells has developed into a major means for the effective development of unconventional oil and gas reservoirs.

[0003] The fracturing sliding sleeve is one of the core components of the horizontal well staged fracturing tool and is the key to affecting the number of fracturing stages in horizontal wells. The Chinese invention patent with the publication number CN115075793A relates to an oil and gas fracturing tool, especially an infinitely variable intelligent sliding sleeve. The specific technical solution is as follows: The infinitely variable intelligent sliding sleeve includes a sliding sleeve part, a dart part, and a control part; the sliding sleeve part includes an upper casing, a lower casing, and a piston; the dart part includes an inner tube, an upper buckle, a lower buckle, a fracturing ball, a ball seat bushing, a ball seat chuck, a rubber cup, a positioning pin, a transmission shaft, a support shaft, a transmission gear, and a bearing; the control circuit includes a strain sensor, a collection circuit, a control circuit, a power supply, and a drive motor. The dart has two states: activated and unactivated. The initial state of the dart is the unactivated state, and it can freely pass through any sliding sleeve during the placement process. The dart is counted once when passing through a sliding sleeve. When passing through the sliding sleeve before the target position, the dart switches from the unactivated state to the activated state. When reaching the specified sliding sleeve, the piston is opened to form a pressure build-up to open the fracturing piston on the casing, achieving the fracturing effect. This kind of sliding sleeve dart has the problem of mis-opening when the counting is inaccurate, and at the same time, the cost of the intelligent sliding sleeve is relatively high, making it difficult to promote and apply at the present stage.

[0004] Again, the Chinese invention patent with the publication number CN113846994A relates to a ball-drop type infinitely variable full-bore fracturing sliding sleeve. It mainly consists of an upper joint, an outer cylinder, a lower joint, elastic claws, grooves, a switch, a liquid outlet, a spring, and a resetable ball seat. Its characteristics are as follows: The upper joint, the outer cylinder, and the lower joint are sequentially connected by threads; through holes are opened on the outer cylinder, and elastic claws are installed inside the outer cylinder. Shearing pins pass through the outer cylinder and the switch to prevent relative movement between the two; the elastic claws are divided into upper elastic claws and lower elastic claws; a liquid outlet is opened on the switch, and its lower end acts on the resetable ball seat. However, when the number of stages is too large, there is a problem with the inappropriate structure of the sliding sleeve.

[0005] The infinite-stage sleeve used in the existing similar technology can achieve infinite-stage fracturing under the condition of equal diameter. Its main technical principle is to deploy the infinite-stage sleeve in the completion string in advance. During the fracturing construction process, the ball seat with the fracturing ball is pumped through the wellhead to match and open the corresponding fracturing sleeve. In the actual field application process of the fracturing sleeve disclosed in the prior art, the ball seat is made of steel material. For wells with sleeve changes, the ball seat made of steel material may not be pumped into place due to the stuck pipe string, and continuous oil pipe needs to be used for salvage, resulting in great risks in the wellbore construction. In addition, the ball seat left in the wellbore also reduces the internal diameter of the pipe string, which also has a certain impact on the repeated transformation of the oil and gas well in the later stage.

[0006] Therefore, there is an urgent need for an infinite-stage sliding sleeve with a fully pumpable ball seat, which can overcome the technical disadvantages of the ball seat being stuck in the pipe column, resulting in inadequate pumping and affecting the internal diameter of the pipe column. Summary of the invention

[0007] One purpose of the present invention is to propose an infinite-stage sliding sleeve and a method of using the same, so as to solve the problems of the existing insoluble ball seat, such as the stuck pipe column causing the pumping to fail and affecting the inner diameter of the pipe column, by adopting the ball seat made of soluble alloy material. At the same time, by changing the main force contact mode of the ball seat made of soluble alloy material, the bearing capacity of the ball seat is greatly improved, and the ball seat made of soluble alloy material is prevented from being easily sheared and damaged at the connection part with the inner sleeve due to insufficient strength, thereby preventing the ball seat from detaching from the inner sleeve and causing construction accidents.

[0008] According to the present invention, an infinite-stage sliding sleeve is provided, comprising a sliding sleeve body having an abutment portion, an inner sleeve, a guide sleeve connected to the inner sleeve, and a ball seat. During the movement of the ball seat in the sliding sleeve, the ball seat can be connected to the inner sleeve and drive the inner sleeve and the guide sleeve to move together, so that the end of the guide sleeve contacts the abutment portion, and the abutment portion can then squeeze the end of the guide sleeve so that it shrinks inwardly until the inner diameter of the end of the guide sleeve is smaller than the outer diameter of the end of the ball seat near the guide sleeve, and the ball seat is made of a soluble alloy material.

[0009] In a preferred embodiment, the abutting portion is configured as a chamfered structure having an inclined surface.

[0010] In a preferred embodiment, the inner walls of the inner sleeve and the guide sleeve are provided with grooves, the ball seat moves inside the inner sleeve and the guide sleeve and a boss is provided on the outer surface of the ball seat, and when the boss passes through the groove, the boss can pop out and snap into the matching groove.

[0011] In a preferred embodiment, the boss has a first inner chamfer and the groove has a second inner chamfer, and the first inner chamfer meshes with the second inner chamfer.

[0012] In a preferred embodiment, the infinitely variable slip sleeve further includes a fixing portion for fixing the inner sleeve to the slip sleeve body. After the boss is snapped into the groove and the first inner chamfer meshes with the second inner chamfer, the ball seat can drive the inner sleeve to cut off the fixing portion.

[0013] In a preferred embodiment, the guide sleeve has a first shoulder portion, and the slip sleeve body has a second shoulder portion. After the end of the guide sleeve contacts the abutting portion, the first shoulder portion can cooperate with the second shoulder portion.

[0014] In a preferred embodiment, the infinitely variable slip sleeve further includes an anti-retreat ring provided on the outer surface of the guide sleeve. The slip sleeve body is provided with a first recess and a second recess that cooperate with the anti-retreat ring in the moving direction of the inner sleeve. During the movement of the inner sleeve, the anti-retreat ring can move from the first recess and snap into the second recess.

[0015] In a preferred embodiment, the ball seat is provided with a plurality of grooves in the axial direction thereof.

[0016] In a preferred embodiment, the guide sleeve is uniformly provided with a plurality of grooves on its end face.

[0017] In a preferred embodiment, if the boss does not match the groove, during the process of the ball seat passing through the infinitely variable slip sleeve, the boss is always in a retracted state and thus cannot pop out until it completely passes through the infinitely variable slip sleeve and is pumped to the next infinitely variable slip sleeve.

[0018] The present invention also provides a method for using an infinitely variable slip sleeve. Using the above-mentioned infinitely variable slip sleeve, it includes the following steps:

[0019] S1. By pumping, the ball seat made of a soluble alloy material together with the fracturing ball enters the infinitely variable slip sleeve and moves therein;

[0020] S2. During the movement of the ball seat inside the infinitely variable slip sleeve, it is connected to the inner sleeve and drives the inner sleeve and the guide sleeve to move together so that the end of the guide sleeve contacts the abutting portion of the slip sleeve body;

[0021] S3. As the well pressure gradually increases, the abutting portion of the slip sleeve body further squeezes the end of the guide sleeve so that it contracts inward until the inner diameter of the end of the guide sleeve is smaller than the outer diameter of the ball seat near the end of the guide sleeve.

[0022] In a preferred embodiment, step S2 specifically includes: during the movement of the ball seat inside the inner sleeve and the guide sleeve, when the boss provided on the outer surface of the ball seat passes through the groove provided on the inner walls of the inner sleeve and the guide sleeve, it can pop out and snap into the matching groove, and the boss has a first inner chamfer, and the groove has a second inner chamfer. When the boss of the ball seat snaps into the matching groove, the first inner chamfer and the second inner chamfer engage with each other.

[0023] On the one hand, since the ball seat of the present invention is made of a soluble alloy material, it can solve the drawbacks of the existing insoluble ball seat such as causing the pumping to be in place due to stuck pipe string and affecting the internal diameter of the pipe string. It realizes that both the fracturing ball and the ball seat are completely dissolved after fracturing. In case of an abnormal situation, KCl solution or acid can be pumped to accelerate the dissolution of the fracturing ball and the ball seat without fishing for the fracturing ball and the ball seat. On the other hand, during the movement of the ball seat of the present invention inside the infinite-stage sliding sleeve, it can be connected to the inner sleeve and drive the inner sleeve and the guide sleeve to move, so that the end of the guide sleeve contacts the abutting portion. As the well pressure gradually increases, the abutting portion can further squeeze the end of the guide sleeve to make it shrink inward until the inner diameter of the end of the guide sleeve is smaller than the outer diameter of the end of the ball seat near this end, thereby greatly reducing the shear force borne by the connection part of the ball seat and the inner sleeve, increasing the extrusion force at the part where the end face of the ball seat contacts the end of the guide sleeve, and greatly improving the bearing capacity of the ball seat by changing the main force contact mode of the ball seat, avoiding the shear failure of the ball seat at the connection part with the inner sleeve due to insufficient strength and excessive shear force, and thus avoiding the separation of the ball seat from the inner sleeve.

[0024] The abutting portion of the sliding sleeve body of the present invention is configured to have a chamfer with an inclined surface. During the process that the ball seat drives the inner sleeve and the guide sleeve to move together and the end of the guide sleeve near the second interface abuts against the abutting portion, as the well pressure gradually increases, the abutting pressure between the end of the guide sleeve and the inclined surface of the abutting portion increases. The abutting portion with the inclined surface can further squeeze the end of the guide sleeve to make it shrink inward until the inner diameter of the end of the guide sleeve is smaller than the outer diameter of the end of the ball seat near this end, thereby greatly reducing the shear force borne by the connection part of the ball seat and the inner sleeve, increasing the extrusion force at the part where the end face of the ball seat contacts the end of the guide sleeve, and greatly improving the bearing capacity of the ball seat.

[0025] The present invention can improve the connection stability between the boss and the groove by having the first inner chamfer on the boss and the second inner chamfer on the groove, and the first inner chamfer and the second inner chamfer engaging with each other, and avoid the separation of the ball seat from the inner sleeve and the guide sleeve.

[0026] The present invention includes a fixing portion for fixing the inner sleeve to the sliding sleeve body. After the boss is inserted into the groove and the first inner chamfer and the second inner chamfer are engaged with each other, the ball seat can drive the inner sleeve so that the inner sleeve has a tendency to move in the direction from the first joint to the second joint for cutting the fixing portion. The fixing portion can fix the inner sleeve and the guide sleeve before the boss is inserted into the groove and the first inner chamfer and the second inner chamfer are engaged with each other, preventing the inner sleeve and the guide sleeve from slipping off in the infinitely variable sliding sleeve. In addition, the fixing portion is easily cut under a certain shearing force, preventing the infinitely variable sliding sleeve from being unable to be opened by the displacement of the inner sleeve and the guide sleeve.

[0027] The guide sleeve of the present invention has a first shoulder portion and the sliding sleeve body has a second shoulder portion. After the end of the guide sleeve contacts the abutting portion, the first shoulder portion can cooperate with the second shoulder portion to prevent the guide sleeve from continuing to move in the direction from the first joint to the second joint, thereby ensuring that the contracted diameter of the end of the guide sleeve is within the designed range and preventing the end of the guide sleeve from being overly contracted under the pressing action of the abutting portion.

[0028] The present invention is provided with an anti-retreat ring on the outer surface of the guide sleeve. The sliding sleeve body is provided with a first recess and a second recess for cooperating with the anti-retreat ring in the moving direction of the inner sleeve. During the movement of the inner sleeve in the direction from the first joint to the second joint, the anti-retreat ring can move from the first recess and be inserted into the second recess, thereby preventing the inner sleeve from closing the fracturing hole due to accidental retreat during the later construction process.

[0029] The present invention includes the following steps: "Pumping to make the ball seat made of soluble alloy material enter the infinitely variable sliding sleeve together with the fracturing ball and move therein; during the movement of the ball seat inside the infinitely variable sliding sleeve, it is connected to the inner sleeve and drives the inner sleeve and the guide sleeve to move together so that the end of the guide sleeve contacts the abutting portion of the sliding sleeve body; as the well pressure gradually increases, the abutting portion of the sliding sleeve body further presses the end of the guide sleeve to make it contract inward until the inner diameter of the end of the guide sleeve is smaller than the outer diameter of the ball seat near the end of the guide sleeve", greatly reducing the shearing force borne by the connecting portion of the ball seat and the inner sleeve, increasing the pressing force at the contact portion between the end face of the ball seat and the end of the guide sleeve. By changing the main force-bearing contact mode of the ball seat, the bearing capacity of the ball seat can be greatly improved, avoiding the shear failure of the connecting portion between the ball seat and the inner sleeve due to insufficient strength and excessive shear force of the ball seat made of soluble alloy material, thereby preventing the ball seat from detaching from the inner sleeve.

[0030] The present invention includes the following steps: "During the movement of the ball seat inside the inner sleeve and the guide sleeve, when the boss provided on the outer surface of the ball seat passes through the groove provided on the inner wall of the inner sleeve and the guide sleeve, it can pop out and snap into the matching groove, and the boss has a first inner chamfer, and the groove has a second inner chamfer. When the boss of the ball seat snaps into the matching groove, the first inner chamfer and the second inner chamfer mesh with each other", which can enable the ball seat to be connected to the inner sleeve during the movement in the infinite - stage sliding sleeve and drive the inner sleeve and the guide sleeve to move together, improving the connection stability between the boss of the ball seat and the grooves of the inner sleeve and the guide sleeve, and preventing the ball seat from detaching from the inner sleeve and the guide sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematically shows an overall structural diagram of an infinite - stage sliding sleeve according to the present invention, wherein the end of the guide sleeve has not yet abutted against the abutting portion;

[0032] Figure 2 Schematically shows another overall structural view of an infinite - stage sliding sleeve according to the present invention, wherein the end of the guide sleeve abuts against the abutting portion and contracts inward.

[0033] Illustration: 100 - infinite - stage sliding sleeve; 1 - first joint; 2 - sliding sleeve body; 3 - inner sleeve; 4 - guide sleeve; 5 - anti - withdrawal ring; 6 - ball seat; 7 - fracturing ball; 61 - first inner chamfer; 23 - second inner chamfer; 24 - first recess; 25 - second recess; 41 - first shoulder; 26 - second shoulder; 42 - end of the guide sleeve; 27 - abutting portion; 62 - end of the ball seat.

[0034] In this application, all the drawings are schematic drawings, only used to illustrate the principle of the present invention and not drawn to actual scale. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of this application can be combined with each other arbitrarily.

[0036] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "inner", "outer", "axial", "radial", etc. is based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 construed as a limitation to the present invention.

[0037] It should be noted that the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0038] In the description of the present invention, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0039] In the present invention, unless otherwise clearly specified and defined, terms such as "connection" and "fixation" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] As Figure 1 shown, the infinite-stage sliding sleeve 100 described in the present invention includes: a sleeve body 2 having an abutting portion, a first joint 1 and a second joint (not shown in the figure) respectively provided at two ends of the sleeve body 2, an inner sleeve 3 and a guide sleeve 4 connected to the inner sleeve 3 respectively provided inside the sleeve body 2, and a ball seat 6 with a fracturing ball 7. The guide sleeve 4 and the inner sleeve 3 are both configured in a cylindrical shape. The ball seat 6 is provided inside the inner sleeve 3 and the guide sleeve 4. Partial inner walls of the guide sleeve 4 and the inner sleeve 3 abut against the outer wall of the ball seat 6. The first joint 1 is closer to the wellhead than the second joint. A plurality of fracturing holes 21 are formed in the sleeve body 2. The outer wall of the inner sleeve 3 abuts against the inner wall of the sleeve body 2. When the infinite-stage sliding sleeve 100 is in the closed state, the inner sleeve 3 and the guide sleeve 4 are fixed and immovable, and the outer wall of the inner sleeve 3 closes the plurality of fracturing holes 21. When the infinite-stage sliding sleeve 100 is in the open state, due to the displacement of the inner sleeve 3 from the first joint 1 towards the second joint 2, a part of the outer wall of the inner sleeve 3 is disengaged from the inner wall of the sleeve body 2 at the plurality of fracturing holes 21, so that the plurality of fracturing holes 21 are exposed.

[0041] The abutment portion 27 on the sleeve body 2 is arranged near the second joint. When the ball seat 6 enters the infinite-stage sleeve 100 and moves inside the sleeve from the first joint 1 to the second joint, it can be connected with the inner sleeve 3 and drive the inner sleeve 3 and the guide sleeve 4 to move together, so that the end 42 of the guide sleeve 4 near the second interface is pressed against the abutment portion 27. As the pressure in the well gradually increases, the abutment portion 27 can squeeze the end 42 of the guide sleeve 4 so that it shrinks inward until the inner diameter of the end 42 of the guide sleeve 4 is smaller than the outer diameter of the end 62 of the ball seat 6 near the end 42. In the present invention, the ball seat 6 and the fracturing ball 7 are both made of soluble alloy material.

[0042] During the process of the ball seat 6 entering the infinite-stage sliding sleeve 100 and moving inside the infinite-stage sliding sleeve 100 from the first joint 1 to the second joint, the ball seat 6 can be connected with the inner sleeve 3 and drive the inner sleeve 3 and the guide sleeve 4 to move together. The connection between the ball seat 6 and the inner sleeve 3 will be subjected to a great shear force during the movement of the ball seat 6 and is easily damaged by shear. If the ball seat 6 is made of only soluble alloy material, the connection between the ball seat 6 and the inner sleeve 3 is very likely to be damaged by shear, causing the ball seat 6 to separate from the inner sleeve 3, which will cause greater safety risks and adverse effects on the construction in the well.

[0043] On the one hand, since the ball seat 6 described in the present invention is made of a soluble alloy material, it can solve the disadvantages of the existing insoluble ball seat that the pumping cannot be carried out properly due to the pipe string being stuck and affecting the diameter of the pipe string, and the fracturing ball 7 and the ball seat 6 are completely dissolved after fracturing. When an abnormal situation occurs, KCl solution or acid can be pumped to accelerate the dissolution of the fracturing ball 7 and the ball seat 6 without having to salvage the fracturing ball 7 and the ball seat 6. On the other hand, the ball seat 6 described in the present invention can be connected with the inner sleeve 3 and drive the inner sleeve 3 and the guide sleeve 4 to move during the movement in the infinite-stage sliding sleeve 100, so that the end of the guide sleeve 4 contacts the abutment 27. As the pressure in the well gradually increases, the abutment 27 can squeeze the end 42 of the guide sleeve 4 so that it shrinks inward until the inner diameter of the end 42 of the guide sleeve 4 is smaller than the outer diameter of the end 62 of the ball seat 6 near the end 42, thereby greatly reducing the shear force on the connection part of the ball seat 6 with the inner sleeve 3, so that the squeezing force of the ball seat 6 at the contact part of the end face 62 with the end 42 of the guide sleeve 4 is increased, and by changing the main force contact mode of the ball seat 6, the bearing capacity of the ball seat 6 is greatly improved, so that it has higher reliability and adaptability, and avoids the ball seat 6 made of soluble alloy having insufficient strength and excessive shear, which causes the ball seat 6 to be easily sheared and damaged at the connection part with the inner sleeve 3, thereby avoiding the ball seat 6 from being separated from the inner sleeve 3.

[0044] In one or more embodiments, the abutment portion 27 of the sleeve body 2 is configured to have a chamfered angle.

[0045] The abutting portion 27 of the sliding sleeve body 2 according to the present invention is configured as a chamfer with an inclined surface. During the process that the ball seat 6 drives the inner sleeve 3 and the guiding sleeve 4 to move together and the end portion 42 of the guiding sleeve 4 near the second interface abuts against the abutting portion 27, as the well pressure gradually increases, the abutting pressure between the end portion 42 of the guiding sleeve 4 and the inclined surface of the abutting portion 27 increases. The abutting portion 27 with an inclined surface can further squeeze the end portion 42 of the guiding sleeve 4 so that it shrinks inward until the inner diameter of the end portion 42 of the guiding sleeve 4 is smaller than the outer diameter of the end portion 62 of the ball seat 6 near this end portion 42, thereby greatly reducing the shear force borne by the connecting portion of the ball seat 6 and the inner sleeve 3, increasing the extrusion pressure at the contact portion between the end surface 62 of the ball seat 6 and the end portion 42 of the guiding sleeve 4, and greatly improving the bearing capacity of the ball seat 6.

[0046] In one or more embodiments, grooves (not shown in the figure) are arranged on the inner walls of the inner sleeve 3 and the guiding sleeve 4. The ball seat 6 moves inside the inner sleeve 3 and the guiding sleeve 4, and a boss (not shown in the figure) is provided on the outer surface of the ball seat 6. The diameter of the ball seat 6 with a boss is larger than the inner diameters of the inner sleeve 3 and the guiding sleeve 4. During the movement of the ball seat 6 inside the infinite-stage sliding sleeve 100, the boss can contract radially and its top surface slides in contact with the inner walls of the inner sleeve 3 and the guiding sleeve 4. When the boss passes through the groove, if the boss matches the groove, the boss can pop out and snap into the groove that matches it to realize the connection between the ball seat 6 and the inner sleeve 3 and the guiding sleeve 4, so as to drive the inner sleeve 3 and the guiding sleeve 4 to move together.

[0047] The inner walls of the inner sleeve 3 and the guiding sleeve 4 according to the present invention are provided with grooves. The ball seat 6 moves inside the inner sleeve 3 and the guiding sleeve 4, and a boss is provided on the outer surface of the ball seat 6. The boss can pop out and snap into the groove that matches it, so as to realize that during the movement of the ball seat 6 inside the infinite-stage sliding sleeve 100, it can be connected to the inner sleeve 3 and drive the inner sleeve 3 and the guiding sleeve 4 to move together.

[0048] In one or more embodiments, the boss has a first inner chamfer 61 and the groove has a second inner chamfer 23, and the first inner chamfer 61 and the second inner chamfer 23 mesh with each other.

[0049] The present invention has the boss with a first inner chamfer 61 and the groove with a second inner chamfer 23, and the first inner chamfer 61 and the second inner chamfer 23 mesh with each other, which can improve the connection stability between the boss and the groove and prevent the ball seat 3 from detaching from the inner sleeve 3 and the guiding sleeve 4.

[0050] In one or more embodiments, the infinitely variable slip sleeve 100 according to the present invention further includes a fixing portion 8 for fixing the inner sleeve 3 to the slip sleeve body 2. The fixing portion 8 can be a shear pin. Under a certain shearing force, the shear pin can be cut off. After the boss is inserted into the groove and the first inner chamfer 61 meshes with the second inner chamfer 23, the ball seat 6 can drive the inner sleeve 3 so that the inner sleeve 3 has a tendency to move in the direction from the first joint 1 to the second joint, thereby applying a shearing force to the fixing portion 8 to cut off the fixing portion 8 and enable the inner sleeve 3 to move.

[0051] The present invention includes a fixing portion 8 for fixing the inner sleeve 3 to the slip sleeve body 2. After the boss is inserted into the groove and the first inner chamfer 61 meshes with the second inner chamfer 23, the ball seat 6 can drive the inner sleeve 3 so that the inner sleeve 3 has a tendency to move in the direction from the first joint 1 to the second joint for cutting off the fixing portion 8. The fixing portion 8 can fix the inner sleeve 3 and the guide sleeve 4 before the boss is inserted into the groove and the first inner chamfer 61 meshes with the second inner chamfer 23, preventing the inner sleeve 3 and the guide sleeve 4 from slipping off within the infinitely variable slip sleeve 100. In addition, the fixing portion 8 is easily cut off under a certain shearing force, preventing the infinitely variable slip sleeve 100 from being unable to be opened by the displacement of the inner sleeve 3 and the guide sleeve 4.

[0052] In one or more embodiments, the guide sleeve 4 has a first shoulder portion 41, and the slip sleeve body 2 has a second shoulder portion 26. After the end portion 42 of the guide sleeve 4 contacts the abutting portion 27, the first shoulder portion 41 can cooperate with the second shoulder portion 26.

[0053] The guide sleeve 4 according to the present invention has a first shoulder portion 41 and the slip sleeve body 2 has a second shoulder portion 26. After the end portion 42 of the guide sleeve 4 contacts the abutting portion 27, the first shoulder portion 41 can cooperate with the second shoulder portion 26 to prevent the guide sleeve 4 from continuing to move in the direction from the first joint 2 to the second joint, thereby ensuring that the contraction diameter of the end portion of the guide sleeve 4 is within the designed range and preventing the end portion of the guide sleeve 4 from being overly contracted under the pressing action of the abutting portion 27.

[0054] In one or more embodiments, the infinitely variable slip sleeve 100 according to the present invention further includes an anti-retreat ring 5 provided on the outer surface of the guide sleeve 4. The anti-retreat ring 5 protrudes outward from the outer wall of the inner sleeve 3. The slip sleeve body 2 is provided with a first recess 24 and a second recess 25 that cooperate with the anti-retreat ring 5 in the moving direction of the inner sleeve 3. During the movement of the inner sleeve 3 in the direction from the first joint 1 to the second joint, the anti-retreat ring 5 can move from the first recess 24 and be caught in the second recess 25.

[0055] In the present invention, an anti-retreat ring 5 is provided on the outer surface of the guiding sleeve 4, and the sliding sleeve body 2 is provided with a first recess 24 and a second recess 25 that cooperate with the anti-retreat ring 5 in the moving direction along the inner sleeve 3. During the movement of the inner sleeve 3 in the direction from the first joint 1 to the second joint, the anti-retreat ring 5 can move from the first recess 24 and snap into the second recess 25, thereby preventing the inner sleeve 3 from closing the fracturing hole 21 due to accidental retreat during the later construction process.

[0056] In one or more embodiments, the ball seat 6 is provided with a plurality of grooves along its axial direction, and the outer diameter of the ball seat 6 is slightly larger than the inner diameters of the inner sleeve 3 and the guiding sleeve 4. By providing a plurality of grooves along the axial direction of the ball seat 6, during the process of the ball seat 6 entering the inner sleeve 3 and the guiding sleeve 4, it is convenient for the ball seat 6 to contract into the inner walls of the inner sleeve 3 and the guiding sleeve 4, so that it can smoothly enter and move in the inner sleeve 3 and the guiding sleeve 4.

[0057] In one or more embodiments, the guiding sleeve 4 is evenly provided with a plurality of grooves at the end portion 42, so as to facilitate its contraction under the extrusion of the abutting portion 72.

[0058] In one or more embodiments, if the boss on the ball seat 6 does not match the groove on the inner sleeve 3 and the guiding sleeve 4, during the process of the ball seat 6 passing through the infinite-stage sliding sleeve 100, the radially compressed boss of the ball seat 6 will always be in a retracted state and thus cannot pop out until it completely passes through the infinite-stage sliding sleeve 100 and is pumped to the next infinite-stage sliding sleeve.

[0059] Based on the above-mentioned infinite-stage sliding sleeve 100, the present invention further provides a method for using the infinite-stage sliding sleeve 100, including the following steps:

[0060] S1. By pumping, the ball seat 6 made of a soluble alloy material together with the fracturing ball 7 enters the infinite-stage sliding sleeve 100 and moves therein;

[0061] S2. During the movement of the ball seat 6 inside the infinite-stage sliding sleeve 100, it is connected to the inner sleeve 3 and drives the inner sleeve 3 and the guiding sleeve 4 to move together, so that the end portion of the guiding sleeve 4 contacts the abutting portion 27 of the sliding sleeve body 2;

[0062] S3. As the well pressure gradually increases, the abutting portion 27 of the sliding sleeve body 2 further squeezes the end portion of the guiding sleeve 4 to make it contract inward until the inner diameter of the end portion of the guiding sleeve 4 is smaller than the outer diameter of the ball seat 6 near the end portion of the guiding sleeve 4.

[0063] In the present invention, through "S1. Pumping enables the ball seat 6 made of a soluble alloy material and the fracturing ball 7 to enter the infinite-stage sliding sleeve 100 and move therein; S2. During the movement of the ball seat 6 inside the infinite-stage sliding sleeve 100, it is connected to the inner sleeve 3 and drives the inner sleeve 3 and the guide sleeve 4 to move together, so that the end of the guide sleeve 4 contacts the abutting portion 27 of the sliding sleeve body 2; S3. As the pressure in the well gradually increases, the abutting portion 27 of the sliding sleeve body 2 further squeezes the end of the guide sleeve 4 to cause it to contract inward until the inner diameter of the end of the guide sleeve 4 is smaller than the outer diameter of the ball seat 6 near the end of the guide sleeve 4", the shear force borne by the connecting portion of the ball seat 6 and the inner sleeve 3 is greatly reduced, the extrusion force at the contact portion between the end face 62 of the ball seat 6 and the end 42 of the guide sleeve 4 is increased, and by changing the main force-bearing contact mode of the ball seat 6, the bearing capacity of the ball seat 6 is greatly improved, avoiding the shear failure of the ball seat 6 at the connecting portion with the inner sleeve 3 due to insufficient strength of the ball seat 6 made of soluble alloy material and excessive shear force, and thus avoiding the separation of the ball seat 6 from the inner sleeve 3.

[0064] Among them, step S2 specifically includes: during the movement of the ball seat 6 inside the inner sleeve 3 and the guide sleeve 4, when the boss provided on the outer surface of the ball seat 6 passes through the groove provided on the inner walls of the inner sleeve and the guide sleeve, it can pop out and snap into the groove matching therewith, and the boss has a first inner chamfer, the groove has a second inner chamfer, and when the boss of the ball seat 6 snaps into the groove matching therewith, the first inner chamfer and the second inner chamfer are engaged with each other.

[0065] In the present invention, through "during the movement of the ball seat 6 inside the inner sleeve 3 and the guide sleeve 4, when the boss provided on the outer surface of the ball seat 6 passes through the groove provided on the inner walls of the inner sleeve and the guide sleeve, it can pop out and snap into the groove matching therewith, and the boss has a first inner chamfer, the groove has a second inner chamfer, and when the boss of the ball seat 6 snaps into the groove matching therewith, the first inner chamfer and the second inner chamfer are engaged with each other", it can be realized that during the movement of the ball seat 6 inside the infinite-stage sliding sleeve 100, it can be connected to the inner sleeve 3 and drive the inner sleeve 3 and the guide sleeve 4 to move together, improving the connection stability between the boss of the ball seat 3 and the grooves of the inner sleeve 3 and the guide sleeve 4, and avoiding the separation of the ball seat 3 from the inner sleeve 3 and the guide sleeve 4.

[0066] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. An infinitely staged sliding sleeve, comprising a sliding sleeve body having an abutting portion, an inner sleeve, a guiding sleeve connected to the inner sleeve, and a ball seat. During the movement of the ball seat within the sliding sleeve, it can be connected to the inner sleeve and drive the inner sleeve and the guiding sleeve to move together, so that the end of the guiding sleeve contacts the abutting portion, and the abutting portion can further squeeze the end of the guiding sleeve to cause it to contract inward until the inner diameter of the end of the guiding sleeve is smaller than the outer diameter of the ball seat near the end of the guiding sleeve. The ball seat is made of a soluble alloy material.

2. The infinitely variable slip sleeve according to claim 1, characterized in that, The abutting portion is configured to have a chamfer structure with an inclined surface.

3. The infinitely variable slip sleeve according to claim 1, characterized in that, Grooves are provided on the inner walls of the inner sleeve and the guiding sleeve. The ball seat moves inside the inner sleeve and the guiding sleeve, and a boss is provided on the outer surface of the ball seat. When the boss passes through the groove, the boss can pop out and snap into the groove that matches it.

4. The infinitely variable slip sleeve according to claim 3, characterized in that, The boss has a first inner chamfer and the groove has a second inner chamfer, and the first inner chamfer and the second inner chamfer are engaged with each other.

5. The infinitely variable slip sleeve according to claim 4, wherein, It further includes a fixing portion for fixing the inner sleeve to the sliding sleeve body. After the boss snaps into the groove and the first inner chamfer and the second inner chamfer are engaged with each other, the ball seat can drive the inner sleeve to cut off the fixing portion.

6. The infinitely variable slip sleeve according to claim 1, wherein The guiding sleeve has a first shoulder portion, and the sliding sleeve body has a second shoulder portion. After the end of the guiding sleeve contacts the abutting portion, the first shoulder portion can cooperate with the second shoulder portion.

7. The infinitely variable slip sleeve according to claim 1, characterized in that, It further includes an anti-retreat ring provided on the outer surface of the guiding sleeve. The sliding sleeve body is provided with a first recess and a second recess that cooperate with the anti-retreat ring in the moving direction along the inner sleeve. During the movement of the inner sleeve, the anti-retreat ring can move from the first recess and snap into the second recess.

8. The infinitely variable slip sleeve according to claim 1, wherein The ball seat is provided with a plurality of grooves in the axial direction thereof.

9. The infinitely variable slip sleeve according to claim 1, characterized in that, The guiding sleeve is evenly provided with a plurality of grooves on its end face.

10. The infinitely variable slip sleeve according to claim 3, characterized in that, If the boss and the groove do not match, during the process of the ball seat passing through the infinitely staged sliding sleeve, the boss is always in a retracted state and thus cannot pop out until it completely passes through the infinitely staged sliding sleeve and is pumped to the next infinitely staged sliding sleeve.

11. A method for using an infinitely staged sliding sleeve, using the infinitely staged sliding sleeve according to any one of claims 1 to 10, comprising the following steps: S1. Pumping causes the ball seat made of a soluble alloy material and the fracturing ball to enter the infinitely staged sliding sleeve and move therein; S2. During the movement of the ball seat inside the infinitely staged sliding sleeve, it is connected to the inner sleeve and drives the inner sleeve and the guiding sleeve to move together, so that the end of the guiding sleeve contacts the abutting portion of the sliding sleeve body; S3. As the pressure in the well gradually increases, the abutting portion of the sliding sleeve body further squeezes the end of the guiding sleeve to cause it to contract inward until the inner diameter of the end of the guiding sleeve is smaller than the outer diameter of the ball seat near the end of the guiding sleeve.

12. The method for using an infinitely variable slip sleeve according to claim 11, wherein Step S2 specifically includes: during the movement of the ball seat inside the inner sleeve and the guide sleeve, when the boss provided on the outer surface of the ball seat passes through the groove provided on the inner wall of the inner sleeve and the guide sleeve, it can pop out and snap into the groove matching therewith, and the boss has a first inner chamfer, the groove has a second inner chamfer, and when the boss of the ball seat snaps into the groove matching therewith, the first inner chamfer and the second inner chamfer are engaged with each other.

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