Positive and negative circulation switch

Abstract

The utility model discloses a positive and negative circulation switch, and relates to the technical field of oil and gas well construction. The positive and negative circulation switch comprises an upper joint and a lower joint, the lower joint sleeves the outer side of the upper joint, and sliding sleeves are arranged on the inner sides of the upper joint and the lower joint; an annular two-layer first stepped structure is arranged on the inner side of one end, inserted into the lower joint, of the upper joint; an annular one-layer second stepped structure is arranged on the inner side of one end, sleeved with the upper joint, of the lower joint; an annular three-layer third step structure is arranged on the outer side of the sliding sleeve, the two-layer step structure of the thin end of the sliding sleeve is matched with the two-layer step structure of the upper connector, and the one-layer step structure of the thick end of the sliding sleeve is matched with the one-layer step structure of the lower connector; a first circulating hole is formed in the side wall of the lower joint; a second circulating hole is formed in the side wall of the sliding sleeve; the minimum end of the sliding sleeve is fixedly connected with the upper connector through a shear pin, a return spring is arranged in the lower connector, and the inner diameter of the position, corresponding to the first circulation hole, of the inner side wall of the sliding sleeve is gradually increased from the upper connector to one side of the lower connector.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas well construction, and particularly relates to a positive and negative circulation switch. Background Art

[0002] During the downhole construction of oil and gas fields, it is often necessary to connect the inner and outer channels of the pipe string for well flushing operations. Therefore, a positive or negative circulation switch is used. When connection is required, it is opened by directly applying pressure or inserting an opening tool. When pressure is applied from the inside of the tubing, it is positive circulation, and when pressure is applied from the annulus between the tubing and the casing, it is negative circulation. Currently, the tools used in general pipe strings are single-function tools, that is, either positive circulation or negative circulation, and the existing tools also have only one function. Therefore, it is impossible to achieve a tool with both positive and negative circulation functions. Content of the Utility Model

[0003] Therefore, the embodiment of the utility model provides a positive and negative circulation switch to solve the above technical problems.

[0004] In order to achieve the above purpose, the embodiment of the utility model provides the following technical solutions:

[0005] A positive and negative circulation switch includes an upper joint and a lower joint. The lower joint is sleeved outside the upper joint, and the upper joint and the lower joint are fixedly connected. A sliding sleeve is arranged inside the upper joint and the lower joint.

[0006] An annular two-layer first stepped structure is arranged inside one end of the upper joint inserted into the lower joint, and its inner diameter gradually becomes thinner from the upper joint to one end of the lower joint.

[0007] An annular one-layer second stepped structure is arranged inside one end of the lower joint sleeving the upper joint, and its inner diameter gradually becomes thicker from the upper joint to one end of the lower joint.

[0008] An annular three-layer third stepped structure is arranged on the outer side of the sliding sleeve, and its inner diameter gradually becomes thicker from the upper joint to one end of the lower joint.

[0009] The two-layer stepped structure at the thin end of the sliding sleeve is adapted to the two-layer stepped structure of the upper joint, and the one-layer stepped structure at the thick end of the sliding sleeve is adapted to the one-layer stepped structure of the lower joint.

[0010] A first circulation hole is opened at a position on the side wall of the lower joint corresponding to the end of the upper joint, and the first circulation hole is tangent to the end face of the upper joint. A second circulation hole is opened at the smallest end of the side wall of the sliding sleeve.

[0011] The smallest end of the sliding sleeve is fixedly connected to the upper joint through a shear pin. A return spring is arranged inside the lower joint. One end of the return spring is fixedly connected to the end of the sliding sleeve, and the other end of the return spring is fixedly connected to the inner wall of the lower joint.

[0012] At the position corresponding to the first circulation hole on the inner side wall of the sliding sleeve, the inner diameter gradually increases from the upper joint to one side of the lower joint, which is used to hold the soluble ball to form a seal inside the sliding sleeve.

[0013] Optionally, a first sealing ring and a sealing ring retainer are arranged between the sliding sleeve and the third stepped structure of the lower joint. An annular sealing groove is formed on the outer side wall of the sliding sleeve, and the first sealing ring and the sealing ring retainer are arranged in the sealing groove.

[0014] Optionally, a second sealing ring is arranged at the position between the first circulation hole and the second circulation hole on the side wall of the sliding sleeve. A tapered sealing groove is formed on the side wall of the sliding sleeve, and the second sealing ring is arranged in the tapered sealing groove.

[0015] Optionally, one or more shear pins are provided.

[0016] Optionally, a third sealing ring is arranged between the shear pin and the upper joint. A sealing groove is formed on the outer side wall of the shear pin, and the third sealing ring is arranged in the sealing groove.

[0017] The utility model has at least the following beneficial effects:

[0018] By arranging the third stepped structure of the sliding sleeve to cooperate with the first stepped structure of the upper joint and the second stepped structure of the lower joint, the sliding sleeve can slide inside the lower joint and the upper joint. When external pressure is applied to the switch, since the outside of the sliding sleeve is stepped, the pressure acts on the difference in the two annular areas, and the sliding sleeve can be pushed towards the end with a larger diameter until the pressure reaches the value to cut the shear pin. The sliding sleeve slides inside the lower joint, and at the same time drives the return spring to be compressed and deformed until the second circulation hole corresponds to the first circulation hole, and the sliding sleeve is completely opened, then the reverse circulation operation can be carried out. After the external pressure is removed, the return spring resets, drives the sliding sleeve to be sealed again, and closes the outlet. When positive circulation is required, a soluble ball is put into the sliding sleeve. The soluble ball is stuck on the slope inside the sliding sleeve, and the force-bearing surface is the side with a larger diameter, which pushes the sliding sleeve to slide, so that the first circulation hole and the second circulation hole are opened again, and then the positive circulation operation can be carried out. After the pressure is removed, the sliding sleeve returns under the action of the return spring, and the sliding sleeve closes the outlet. The soluble ball dissolves by itself after a certain time, which will not affect the subsequent construction. Thus, one switch can complete both the positive circulation and the reverse circulation operations, meeting the requirements of on-site construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the prior art and the present utility model, the drawings required for describing the prior art and the embodiments of the present utility model will be briefly introduced below. Obviously, the drawings described below are only exemplary. For those of ordinary skill in the art, other drawings can be obtained by extension based on the provided drawings without creative efforts.

[0020] The structures, proportions, sizes, etc. illustrated in this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present utility model. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present utility model can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present utility model.

[0021] Figure 1 It is a schematic structural diagram of the initial state of an embodiment of the present utility model;

[0022] Figure 2 It is a schematic structural diagram of the reverse circulation state of an embodiment of the present utility model;

[0023] Figure 3 It is a schematic structural diagram of the positive circulation state of an embodiment of the present utility model.

[0024] Explanation of the reference numerals in the drawings:

[0025] 1. Upper joint; 2. Lower joint; 3. Slip sleeve; 4. First stepped structure; 5. Second stepped structure; 6. Third stepped structure; 7. First circulation hole; 8. Second circulation hole; 9. Return spring; 10. Soluble ball; 11. First sealing ring; 12. Second sealing ring; 13. Third sealing ring; 14. Shearing pin. Specific embodiments

[0026] In order to make the purpose, technical solutions and advantages of this application clearer, the following further details this application in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0027] In the description of the present utility model, unless otherwise specified, "a plurality" means two or more. The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present utility model and the above-mentioned drawings are intended to distinguish the objects being referred to. For a solution with a time sequence process, such a term expression does not necessarily need to be understood as describing a specific order or sequence, and for a solution of a device structure, such a term expression also does not distinguish the importance level, positional relationship, etc.

[0028] In addition, the terms "comprising", "having", and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units need not be limited to those steps or units that are expressly listed, but may also include other steps or units that are inherent to these processes, methods, products, or devices although not expressly listed, or steps or units added based on further optimization solutions of the inventive concept of the present utility model.

[0029] As Figures 1-3 shown, a positive and negative circulation switch disclosed by the present utility model includes an upper joint 1 and a lower joint 2. The lower joint 2 is sleeved outside the upper joint 1, and the upper joint 1 and the lower joint 2 are fixedly connected. A sliding sleeve 3 is arranged inside the upper joint 1 and the lower joint 2;

[0030] An annular two-layer first stepped structure 4 is arranged inside one end of the upper joint 1 inserted into the lower joint 2, and its inner diameter gradually becomes thinner from the upper joint 1 to one end of the lower joint 2;

[0031] An annular single-layer second stepped structure 5 is arranged inside one end of the lower joint 2 sleeved on the upper joint 1, and its inner diameter gradually becomes thicker from the upper joint 1 to one end of the lower joint 2;

[0032] An annular three-layer third stepped structure 6 is arranged outside the sliding sleeve 3, and its inner diameter gradually becomes thicker from the upper joint 1 to one end of the lower joint 2;

[0033] The two-layer stepped structure at the thin end of the sliding sleeve 3 is adapted to the two-layer stepped structure of the upper joint 1, and the single-layer stepped structure at the thick end of the sliding sleeve 3 is adapted to the single-layer stepped structure of the lower joint 2;

[0034] A first circulation hole 7 is opened at a position on the side wall of the lower joint 2 corresponding to the end of the upper joint 1, and the first circulation hole 7 is tangent to the end face of the upper joint 1. A second circulation hole 8 is opened at the smallest end of the side wall of the sliding sleeve 3;

[0035] The smallest end of the sliding sleeve 3 is fixedly connected to the upper joint 1 through a shear pin 14. A return spring 9 is arranged inside the lower joint 2. One end of the return spring 9 is fixedly connected to the end of the sliding sleeve 3, and the other end of the return spring 9 is fixedly connected to the inner wall of the lower joint 2;

[0036] The inner diameter at the position of the inner side wall of the sliding sleeve 3 corresponding to the first circulation hole 7 gradually becomes larger from the upper joint 1 to one side of the lower joint 2, so as to clamp the soluble ball 10 to form a seal inside the sliding sleeve 3.

[0037] The above upper joint 1 and lower joint 2 are generally annular cylindrical structures. The right end part of the upper joint 1 is inserted into the interior of the lower joint 2. The specific connection between the two is that an inwardly concave annular groove is provided on the outer end face of the upper joint 1. The outer diameter of the annular groove is adapted to the inner diameter of the lower joint 2. External threads are provided in the annular groove, and corresponding internal threads are provided on the inner side surface of the lower joint 2. The lower joint 2 and the upper joint 1 are fixedly connected by screw threads;

[0038] A first stepped structure 4 is provided on the inner wall of the upper joint 1. The first stepped structure 4 starts from the end face where the upper joint 1 is inserted into the lower joint 2 and gradually rises, that is, the inner diameter gradually becomes smaller. The first stepped structure 4 is provided with two layers (starting from the horizontal part, a continuous horizontal part and vertical part are one layer);

[0039] A second stepped structure 5 is provided on the inner wall of the lower joint 2. The second stepped structure 5 starts from the end face where the lower joint 2 is sleeved on the upper joint 1 and gradually rises, that is, the inner diameter gradually becomes smaller. The second stepped structure 5 is provided with one layer (starting from the horizontal part, a continuous horizontal part and vertical part are one layer);

[0040] A third stepped structure 6 is provided on the outer wall of the sliding sleeve 3. The third stepped structure 6 rises gradually from one side of the upper joint 1 to the lower joint 2, that is, the outer diameter gradually becomes larger. The third stepped structure 6 is provided with three layers (starting from the vertical part, a continuous vertical part and horizontal part are one layer);

[0041] In the initial state, the fit between the upper joint 1, the lower joint 2 and the sliding sleeve 3 is as follows: After the first vertical part at the thin end of the sliding sleeve 3 is opposite to the last vertical part (starting from the thin end) at the thick end of the upper joint 1, then the two horizontal parts are connected in sequence. The last horizontal part of the sliding sleeve 3 is connected to the horizontal part of the lower joint 2. Then, a shear pin 14 is driven into the outer wall of the upper joint 1 to fix the smallest end of the sliding sleeve 3 to the upper joint 1;

[0042] The sliding sleeve 3 can slide along the horizontal parts of the upper joint 1 and the lower joint 2. After the sliding sleeve 3 slides to be limited by the vertical part of the third stepped structure 6, its displacement length is exactly the distance difference between the first circulation hole 7 and the second circulation hole 8 in the axial direction of the switch;

[0043] The return spring 9 is arranged inside the lower joint 2, with one end fixed on the sliding sleeve 3 and the other end fixed on the inner wall of the lower joint 2 far from the upper joint 1. The sliding of the sliding sleeve 3 can drive the return spring 9 to compress and deform.

[0044] Since a certain pressure requirement is needed for the initial opening of the switch, according to the pressure requirement, a corresponding number of shear pins 14 or shear pins 14 of corresponding size are set. After that, the pressure for the second opening can be adjusted according to the pre-compressed return spring 9.

[0045] In the operation of the positive cycle, it is necessary to put the soluble ball 10 inside the sliding sleeve 3, and the soluble ball 10 needs to be stuck inside the sliding sleeve 3 for sealing. A slope mechanism with an inner diameter gradually increasing (from the upper joint 1 to the lower joint 2 side) is arranged inside the sliding sleeve 3;

[0046] Moreover, the greater the slope, the more convenient it is to hold the soluble ball 10. Without changing the diameter of the sliding sleeve 3, the two ends inside the sliding sleeve 3 can be set as horizontal planes, and a slope section is arranged between the two horizontal planes, and the slope angle can be increased to make it more convenient to hold the soluble ball 10.

[0047] The soluble ball 10 put in during the positive cycle will dissolve after the cycle is completed, without affecting subsequent construction.

[0048] A first sealing ring 11 and a sealing ring retaining ring are arranged between the sliding sleeve 3 and the third stepped structure 6 of the lower joint 2. An annular sealing groove is formed on the outer side wall of the sliding sleeve 3, and the first sealing ring 11 and the sealing ring retaining ring are arranged in the sealing groove.

[0049] A second sealing ring 12 is arranged on the side wall of the sliding sleeve 3 at the position between the first circulation hole 7 and the second circulation hole 8. A tapered sealing groove is formed on the side wall of the sliding sleeve 3, and the second sealing ring 12 is arranged in the tapered sealing groove.

[0050] The left sealing groove of the sliding sleeve 3 adopts a tapered groove to prevent the second sealing ring 12 from coming out when the sliding sleeve 3 is opened.

[0051] A third sealing ring 13 is arranged between the shear pin 14 and the upper joint 1. A sealing groove is formed on the outer side wall of the shear pin 14, and the third sealing ring 13 is arranged in the sealing groove.

[0052] The shear pin 14 is equipped with its own sealing ring to prevent the internal and external pressures from communicating.

[0053] For some oil and gas wells, the construction process is generally one of the positive cycle and the reverse cycle. Therefore, only the corresponding circulation switch will be lowered according to the process requirements when lowering the pipe string; however, due to special reasons, when it is necessary to change the circulation process, it is necessary to lift the pipe string again and replace the circulation switch. If the positive and reverse circulation switches are connected in the previous pipe string, there is no need to lift the pipe string again to change the construction process, and the positive cycle and the reverse cycle can be selected at any time; therefore, this tool can improve the overall work efficiency and save costs in the case of changing the on-site circulation process.

[0054] The positive cycle and the reverse cycle functions are realized on the same tool. This circulation switch can perform circulation operations multiple times, and the positive cycle and the reverse cycle processes can be alternately implemented; whether it is a positive cycle or a reverse cycle operation, after the pressure is relieved, the circulation switch can automatically reset to separate the internal and external pressures.

[0055] Working principle

[0056] Reverse circulation operation:

[0057] Pressurize from the outside of the switch. Since d1 > d2, the pressure acts on the difference between the two annular areas, pushing the sliding sleeve 3 to the right. When the thrust reaches the shear force of the shear pin 14, the shear pin 14 is sheared, and the sliding sleeve 3 is released. When continuous pressure is applied, the sliding sleeve 3 compresses the return spring 9 to the right. As the pressure increases, the sliding sleeve 3 finally reaches the limit point, at which time the sliding sleeve 3 is fully opened, and the reverse circulation operation can be carried out. When the external pressure is removed, the sliding sleeve 3 moves to the left under the action of the spring, and the sealing ring enters the sealing position for stroke sealing, and then the sliding sleeve 3 closes the outlet.

[0058] Positive circulation operation:

[0059] Put the soluble ball 10 from the inside and pressurize from the inside of the switch. The current force-bearing area is the diameter d2, so the pressure acts on this area, pushing the sliding sleeve 3 to the right. When the thrust reaches the shear force of the shear pin 14, the shear pin 14 is sheared, and the sliding sleeve 3 is released. When continuous pressure is applied, the sliding sleeve 3 compresses the return spring 9 to the right. As the pressure increases, the sliding sleeve 3 finally reaches the limit point, at which time the sliding sleeve 3 is fully opened, and the positive circulation operation can be carried out. When the internal pressure is removed, the sliding sleeve 3 moves to the left under the action of the spring, and the sealing ring enters the sealing position for stroke sealing, and then the sliding sleeve 3 closes the outlet. When the soluble ball 10 dissolves itself after a certain time, the channel is completely unblocked, thus not affecting subsequent construction.

[0060] In the working principles of the above-mentioned reverse circulation operation and positive circulation operation, the shear pin 14 is sheared only in the initial operation, and the shear pin 14 is not sheared in subsequent multiple cyclic operations. The cyclic operation is completed through the return spring 9.

[0061] The above several specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in some embodiments.

[0062] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope described in this specification.

[0063] In the above text, the present invention has been described in a relatively specific and detailed manner through general descriptions and specific embodiments. It should be noted that, without departing from the concept of the present invention, it is obvious that several deformations and improvements can still be made to these specific embodiments, and these all belong to the protection scope of this application. Therefore, the protection scope of the patent of this application should be subject to the appended claims.

Claims

1. A forward and reverse cycle switch, characterized in that: It comprises an upper joint and a lower joint, wherein the lower joint is sleeved on the outer side of the upper joint, the upper joint and the lower joint are fixedly connected, and a sliding sleeve is arranged on the inner side of the upper joint and the lower joint; The inner side of one end of the upper joint inserted into the lower joint is provided with an annular two-layer first step structure, the inner diameter of which gradually tapers from the upper joint to one end of the lower joint; The inner side of one end of the lower joint sleeved with the upper joint is provided with a second step structure of an annular layer, the inner diameter of which gradually increases from the upper joint to one end of the lower joint; The outer side of the sliding sleeve is provided with an annular three-layer third step structure, the inner diameter of which gradually increases from the upper joint to one end of the lower joint; The two-layer step structure of the thin end of the sliding sleeve is adapted to the two-layer step structure of the upper joint, and the one-layer step structure of the thick end of the sliding sleeve is adapted to the one-layer step structure of the lower joint; A first circulation hole is provided at a position on the side wall of the lower joint corresponding to the end of the upper joint, and the first circulation hole is tangent to the end surface of the upper joint, and a second circulation hole is provided at the smallest end of the side wall of the sliding sleeve; The smallest end of the sliding sleeve is fixedly connected through the shear nail upper joint, and a return spring is arranged inside the lower joint, one end of the return spring is fixedly connected to the end of the sliding sleeve, and the other end of the return spring is fixedly connected to the inner wall of the lower joint; The inner diameter of the inner side wall of the sleeve at a position corresponding to the first circulation hole gradually increases from the upper joint to the lower joint, so as to clamp the soluble ball to form a seal inside the sleeve.

2. A forward and reverse cycle switch according to claim 1, characterized in that: A first sealing ring and a sealing ring retaining ring are arranged between the sliding sleeve and the third step structure of the lower joint, an annular sealing groove is opened on the outer side wall of the sliding sleeve, and the first sealing ring and the sealing ring retaining ring are arranged in the sealing groove.

3. A forward and reverse cycle switch according to claim 1, characterized in that: A second sealing ring is arranged on the side wall of the sliding sleeve at a position between the first circulation hole and the second circulation hole, a conical sealing groove is opened on the side wall of the sliding sleeve, and the second sealing ring is arranged in the conical sealing groove.

4. A forward and reverse cycle switch according to claim 1, characterized in that: The shear pins are provided with one or more.

5. A forward and reverse cycle switch according to claim 1, characterized in that: A third sealing ring is arranged between the shear pin and the upper joint, a sealing groove is opened on the outer side wall of the shear pin, and the third sealing ring is arranged in the sealing groove.

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