An infinitely graded full-bore fracturing sliding sleeve

Abstract

The present invention provides an infinitely graded full-bore fracturing sleeve. The fracturing sleeve includes an upper joint, a lower joint, an inner sleeve, a shear connecting member and a positioning groove. The positioning groove is formed on the inner peripheral wall of the upper joint and has a predetermined length in the up-down direction. The length of the positioning groove of the upper one of any two adjacent fracturing sleeves installed in an oil and gas well is less than that of the lower one. The length of the positioning elastic member of each opening mechanism corresponds to the length of the positioning groove of only one sub-fracturing sleeve. The advantages of the present invention include that after fracturing of all layers is completed, the entire pipe string is a full bore without the need for drilling operation, which is beneficial to later production management. Series connection of multiple sleeves can achieve infinite grading; the operation risk is low and the operation efficiency is high; the device structure is reasonably designed and is easy to process and assemble.

Description

Technical Field

[0001] The present invention relates to the technical field of downhole fracturing tools in the oil and gas industry. Specifically, it relates to an infinitely staged full-bore fracturing sleeve with a novel structure. Background Art

[0002] Generally speaking, according to the current situation, the exploration and development of unconventional tight gas reservoirs and shale gas will be key development areas in the future.

[0003] The inventor states that for the stimulation operations of such gas reservoirs, an infinitely staged casing completion method can be adopted. For example, a coiled tubing with tools is required to be used for opening. However, the inventor has found that the following deficiencies may exist during the process of using a coiled tubing with tools for opening: If the casing is deformed, it may cause the coiled tubing to get stuck, and it cannot be lowered to the designated position to open the sleeve. There are also problems such as high operation risks, low operation efficiency, and high costs for the coiled tubing in the well. Summary of the Invention

[0004] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies existing in the prior art. For example, one of the purposes of the present invention is to provide a fracturing sleeve with a novel structure. Another purpose of the present invention is to provide a fracturing sleeve that has a full bore inside the pipe string, does not require coiled tubing for opening operations, has no limit on the number of fracturing stages, and does not require drilling and milling operations.

[0005] To achieve the above purpose, the present invention provides an infinitely staged full-bore fracturing sleeve. The infinitely staged full-bore fracturing sleeve includes an upper joint, a lower joint, an inner sleeve, a shear connecting member, and a positioning groove. Among them, the upper joint and the lower joint are coaxially fixedly connected to form an outer cylinder body, and a fracturing hole is penetrated through the circumferential wall of the upper joint; the shear connecting member fixedly connects the inner sleeve sleeved inside the outer cylinder body to the upper joint, so that the inner sleeve is in a first position covering the fracturing hole of the upper joint; the positioning groove is a recess formed on the inner circumferential wall of the upper joint and having a predetermined length in the up and down direction, and the recess is located above the inner sleeve.

[0006] In an exemplary embodiment of the present invention, the infinitely staged full-bore fracturing sleeve may further include a first sealing member and a second sealing member disposed between the inner sleeve and the outer cylinder body. Among them, the first sealing member is disposed on the outer circumference of the lower end of the inner sleeve, and the second sealing member is disposed on the outer circumference of the upper end of the inner sleeve.

[0007] In an exemplary embodiment of the present invention, the number of the fracturing holes can be 6 to 10, and they can be evenly disposed on the circumferential wall of the upper joint.

[0008] In an exemplary embodiment of the present invention, the recess can be an annular recess.

[0009] In an exemplary embodiment of the present invention, the infinitely graded full-bore fracturing sliding sleeve may further include an opening mechanism. Further, the opening mechanism may have a cylinder and a positioning elastic member provided on the cylinder, and the diameter of the cylinder can enable itself to pass through the inner sleeve; the length of the positioning elastic member corresponds to the predetermined length of the positioning groove, so that when the opening mechanism reaches the positioning groove, the positioning elastic member can be opened, and thus the positioning elastic member of the opening mechanism can be embedded into the positioning groove. For example, the opening mechanism may be made of a soluble alloy.

[0010] Compared with the prior art, the beneficial effects of the present invention include one or more of the following:

[0011] (1) A new type of fracturing sliding sleeve for oil and gas wells is obtained;

[0012] (2) It is beneficial to realize the integrated operation of casing cementing completion and fracturing reconstruction;

[0013] (3) The device structure is reasonably designed and is easy to process and assemble. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The structural schematic diagram of an exemplary embodiment of the infinitely graded full-bore fracturing sliding sleeve of the present invention is shown;

[0015] Figure 2 The schematic diagram of the cooperation between an exemplary embodiment of the infinitely graded full-bore fracturing sliding sleeve of the present invention and the opening mechanism is shown;

[0016] Figure 3 The schematic diagram of an exemplary embodiment of the infinitely graded full-bore fracturing sliding sleeve of the present invention in the state where the sliding sleeve is opened;

[0017] Figure 4 Shown is Figure 2 the schematic diagram of the opening mechanism used in

[0018] The description of the reference numerals is as follows:

[0019] 1. Upper joint, 2. Sealing ring, 3. Fracturing hole, 4. Pin, 5. Inner sleeve, 6. Lower joint, 7. Positioning groove. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Hereinafter, the infinitely graded full-bore fracturing sliding sleeve of the present invention will be described in detail in conjunction with exemplary embodiments.

[0021] In the first exemplary embodiment of the present invention, the infinitely graded full-bore fracturing sliding sleeve (which may also be referred to as a sub-fracturing sliding sleeve) may include an upper joint, a lower joint, an inner sleeve, a shear connecting member, and a positioning groove.

[0022] Wherein, the upper joint and the lower joint are coaxially fixedly connected to form an outer cylinder body, and a fracturing hole is penetratingly provided on the circumferential wall of the upper joint. For example, the upper joint can be coaxially connected to the lower joint by threads. However, the present invention is not limited thereto. The fracturing openings can be a plurality of openings uniformly arranged on the circumferential wall of the upper joint and penetrating the circumferential wall in the radial direction. For example, the number thereof can be 4 to 10. However, the present invention is not limited thereto.

[0023] The inner sleeve (which can also be called an inner sliding sleeve) is sleeved inside the outer cylinder body and fixedly connected to the upper joint through a shear connecting member, so that the inner sleeve can cover the position of the fracturing hole covering the upper joint (denoted as the first position). For example, the first position of the inner sleeve can be located in the upper part, the upper middle part or the middle part of the outer cylinder body, so that the inner sleeve can move to the lower part of the outer cylinder body and expose the fracturing opening after detaching from the shear connecting member. At this time, the corresponding position of the inner sleeve can be denoted as the second position. The shear connecting member can be a pin. However, the present invention is not limited thereto.

[0024] The positioning groove is arranged to be recessed on the inner circumferential wall of the upper joint. The recess has a predetermined length in the up and down direction, and the recess is located above the inner sleeve. For example, the recess is located between the upper end of the inner sleeve and the upper joint. In addition, the positioning groove can be an annular recess, which is more conducive to cooperating with the positioning elastic member of the opening mechanism.

[0025] In another exemplary embodiment of the present invention, the infinitely staged full-bore fracturing sliding sleeve may further include a first seal and a second seal provided between the inner sleeve and the outer cylinder body. The first seal is provided on the outer circumference of the lower end portion of the inner sleeve, and the second seal is provided on the outer circumference of the upper end portion of the inner sleeve. For example, the first and second seals can be sealing rings.

[0026] Figure 1 The structural schematic diagram of an exemplary embodiment of the infinitely staged full-bore fracturing sliding sleeve of the present invention is shown.

[0027] As Figure 1 shown, in the second exemplary embodiment of the present invention, the infinitely staged full-bore fracturing sliding sleeve may include an outer cylinder body and an inner sliding sleeve provided inside the outer cylinder body. Wherein, the outer cylinder body is composed of an upper joint 1 and a lower joint 6, and the two can be coaxially connected by threads. 8 fracturing holes 3 are evenly distributed on the outer surface circumference of the upper joint 1, and the fracturing holes 3 penetrate through the inside and outside of the upper joint 1. The upper end of the upper joint can be connected to the upper pipe string, and the lower end of the lower joint can be connected to the lower pipe string.

[0028] The inner sliding sleeve is composed of an inner sleeve 5, and the inner sleeve 5 is slidably and sealingly fitted with the upper joint 1 and the lower joint 6 through a sealing ring 2. When the inner sleeve 5 is in the initial state (equivalent to the inner sleeve being in the first position), it is fitted and installed in the upper joint through a pin 4 and can cover the fracturing hole 3; when the inner sliding sleeve moves downward to the bottom of the lower joint 6 (equivalent to the inner sleeve being in the second position), the fracturing hole 3 on the upper joint penetrates through the inside and outside of the pipe.

[0029] When the inner sleeve 5 is installed in the upper joint 1, a ring-shaped positioning groove 7 is formed between the inner sleeve 5 and the upper joint 1. The positioning groove 7 is used to position the corresponding opening mechanism (which can also be called an opening tool). Specifically, the opening mechanism with different lengths can be corresponded by setting the positioning groove with different lengths in the up and down direction.

[0030] Several pins 4 can be provided between the outer cylinder (for example, the upper joint) and the inner sleeve.

[0031] In order to facilitate the better sliding fit between the inner sleeve 5 and the upper joint 1 and the lower joint 6, a sealing ring can be provided on the sealing surface between the upper joint and the inner sleeve; another sealing ring can be provided on the sealing surface between the lower joint and the inner sleeve.

[0032] Figure 2 The schematic diagram showing the cooperation between an exemplary embodiment of the infinitely staged full-bore fracturing sliding sleeve of the present invention and the opening mechanism is shown. Figure 3 The schematic diagram of an exemplary embodiment of the infinitely staged full-bore fracturing sliding sleeve of the present invention in the state where the sliding sleeve is opened. Figure 4 It shows Figure 2 the schematic diagram of the opening mechanism used in

[0033] As Figures 1 to 4 shown, for the infinitely staged full-bore fracturing sliding sleeve of this exemplary embodiment, its construction and use steps can be as follows:

[0034] Lower the infinitely staged full-bore fracturing sliding sleeve together with the casing to the designed position and complete the cementing operation construction. The lengths of the annular positioning grooves of each infinitely staged full-bore fracturing sliding sleeve are different, and the length of the positioning groove decreases step by step from bottom to top. That is to say, the lower the infinitely staged full-bore fracturing sliding sleeve is in the well, the longer the length of its positioning groove.

[0035] Prepare multiple opening mechanisms. As Figure 4As shown, each opening mechanism may have a cylinder and a positioning elastic member (e.g., a positioning elastic sheet) disposed on the cylinder. The diameter of the cylinder enables itself to pass through the inner sleeve. The length of the positioning elastic member of each opening mechanism among multiple opening mechanisms corresponds to the length of the positioning groove of a unique infinitely graded full-bore fracturing sliding sleeve, so that when this opening mechanism reaches the positioning groove corresponding to the length, it can open its positioning elastic member, thereby embedding the positioning elastic member of this opening mechanism into the positioning groove corresponding to the length.

[0036] A plurality of opening mechanisms are successively put into the wellhead, and the putting order of the opening mechanisms corresponds to the length of the positioning groove of the corresponding infinitely graded full-bore fracturing sliding sleeve according to the length of their positioning elastic members (e.g., positioning elastic sheets) from long to short.

[0037] Specifically, the wellhead pumps liquid to push the opening mechanism to move along the casing. When the opening mechanism passes through the positioning groove with a short length, the positioning elastic sheet will not open for positioning; when it continues to move downward to the positioning groove corresponding to the length, the positioning elastic sheet opens to be positioned in the annular positioning groove of the sliding sleeve, as Figure 2 shown; continue to pump liquid to build pressure in the pipe to shear the pin, and push the opening mechanism to drive the inner sleeve to move downward together, exposing the fracturing holes to realize communication between the inside and outside of the pipe, as Figure 3 shown, and then complete the opening of the sliding sleeve and carry out the fracturing operation. After the fracturing operation of this stage is completed, the next-stage opening mechanism is put into the wellhead, and in this way, each infinitely graded full-bore fracturing sliding sleeve is positioned and opened successively upward until the fracturing of the entire well section is completed.

[0038] In the third exemplary embodiment of the present invention, the infinitely graded full-bore fracturing sliding sleeve assembly system may include a plurality of opening mechanisms and a plurality of sub-fracturing sliding sleeves connected in series through pipes, and the recessed length of the upper sub-fracturing sliding sleeve among any two adjacent sub-fracturing sliding sleeves in the plurality of sub-fracturing sliding sleeves is less than the recessed length of the lower sub-fracturing sliding sleeve.

[0039] Each sub-fracturing sliding sleeve among the plurality of sub-fracturing sliding sleeves may have the structure of the infinitely graded full-bore fracturing sliding sleeve in the above first exemplary embodiment or second exemplary embodiment.

[0040] Specifically, each sub-fracturing sliding sleeve may include an upper joint, a lower joint, an inner sleeve, a shear connecting member, and a positioning groove. Among them, the upper joint and the lower joint are coaxially fixedly connected to form an outer cylinder body, and a fracturing hole is penetrated through the circumferential wall of the upper joint. For example, the upper joint may be coaxially connected to the lower joint by threads. However, the present invention is not limited thereto. The fracturing openings may be a plurality of openings uniformly arranged on the circumferential wall of the upper joint and penetrating through the circumferential wall in the radial direction. For example, the number thereof may be 4 to 10. However, the present invention is not limited thereto.

[0041] The inner sleeve assembly is disposed inside the outer cylinder body and fixedly connected to the upper joint through a shear connector, so that the inner sleeve can cover the fracturing hole position (denoted as the first position) covering the upper joint. For example, the first position of the inner sleeve can be located at the upper part, the upper middle part or the middle part of the outer cylinder body, so that after the inner sleeve is separated from the shear connector, it can move to the lower part of the outer cylinder body and expose the fracturing port, and the corresponding position of the inner sleeve at this time can be denoted as the second position. The shear connector can be a pin, however, the present invention is not limited thereto.

[0042] The positioning groove is arranged to be recessed on the inner peripheral wall of the upper joint, the recess has a predetermined length in the up and down direction, and the recess is located above the inner sleeve. For example, the recess is located between the upper end of the inner sleeve and the upper joint. In addition, the positioning groove can be an annular recess, which is more conducive to cooperating with the positioning elastic member of the opening mechanism.

[0043] Each of the plurality of opening mechanisms can have a cylinder body and a positioning elastic member (for example, a positioning spring piece) arranged on the cylinder body. The diameter of the cylinder body enables the opening mechanism to pass through the inner sleeve. The length of the positioning elastic member of each of the plurality of opening mechanisms corresponds to the length of the positioning groove of only one infinitely graded full-bore fracturing sliding sleeve, so that when this opening mechanism reaches the positioning groove corresponding to the length, it can open its positioning elastic member, so as to embed the positioning elastic member of this opening mechanism into the positioning groove corresponding to the length. For example, in the infinitely graded full-bore fracturing sliding sleeve assembly, the number of the plurality of opening mechanisms can be equal to the number of the plurality of sub-fracturing sliding sleeves. Here, the opening mechanism can be made of a soluble alloy (for example, soluble magnesium aluminum alloy), so that after all stages of fracturing are completed, the entire pipe string becomes a full bore after the opening mechanism dissolves.

[0044] In another exemplary embodiment of the present invention, each sub-fracturing sliding sleeve may further include a first seal and a second seal disposed between the inner sleeve and the outer cylinder body. The first seal is disposed on the outer circumference of the lower end portion of the inner sleeve, and the second seal is disposed on the outer circumference of the upper end portion of the inner sleeve. For example, the first and second seals can be sealing rings.

[0045] In the fourth exemplary embodiment of the present invention, the fracturing construction process can be realized by using the infinitely graded full-bore fracturing sliding sleeve assembly system as described in the above third exemplary embodiment through the following steps:

[0046] Install a plurality of sub-fracturing sliding sleeves connected in series through pipelines into the oil and gas well.

[0047] Lower the opening mechanism corresponding to the lowermost sub-fracturing sleeve among the multiple sub-fracturing sleeves into the well. The length of the positioning elastic member of the opening mechanism corresponds to the length of the positioning groove of the lowermost sub-fracturing sleeve. Therefore, the opening mechanism can sequentially pass through the remaining upper sub-fracturing sleeves until it reaches the positioning groove of the lowermost sub-fracturing sleeve, and the positioning elastic member of the opening mechanism expands and positions. As the pumped liquid builds up pressure to shear the shear connecting member of the lowermost sub-fracturing sleeve, the inner sleeve of the lowermost sub-fracturing sleeve moves downward together with the opening mechanism, exposing the fracturing port of the lowermost sub-fracturing sleeve, realizing the fracturing of this sub-fracturing sleeve (which can also be called the fracturing of this stage).

[0048] Then, according to the above steps for realizing fracturing, use the opening mechanism with a positioning elastic member of corresponding length to sequentially fracture the fracturing ports of the remaining sub-fracturing sleeves among the multiple sub-fracturing sleeves upward until the fracturing of the entire well section is completed.

[0049] In summary, the present invention is applicable to the integrated operation of casing cementing completion and fracturing reconstruction, and its advantages include at least one of the following:[[]]END]

[0050] After all layers are fractured, there is no need for drilling removal operation, and the entire pipe string is full-bore, which is beneficial to subsequent production management, and infinite levels can be achieved by series connection of multiple-stage sleeves;

[0051] By installing the inner sleeve in the upper joint and forming a positioning groove with adjustable length between the inner sleeve and the upper joint, which can cooperate with the opening mechanism, the device structure is more reasonable, the fracturing construction process is easy to operate, and the operation risk is low and the operation efficiency is high;

[0052] The device structure is reasonably designed and is easy to process and assemble.

[0053] Although the present invention has been described above in conjunction with exemplary embodiments and the accompanying drawings, those of ordinary skill in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. An infinitely graded full-bore fracturing sliding sleeve, characterized in that The infinite staged full-bore fracturing sliding sleeve includes an upper joint, a lower joint, an inner sleeve, a shear connecting member, and a positioning groove. Among them, the upper joint and the lower joint are coaxially fixedly connected to form an outer cylinder body, and a fracturing hole is penetratingly provided on the circumferential wall of the upper joint; the number of the fracturing holes is 6 to 10, and they are evenly arranged on the circumferential wall of the upper joint; the shear connecting member fixedly connects the inner sleeve sleeved in the outer cylinder body with the upper joint, so that the inner sleeve is in the first position covering the fracturing holes of the upper joint; the positioning groove is a recess formed on the inner circumferential wall of the upper joint and having a predetermined length in the up-down direction, and the recess is located above the inner sleeve; the infinite staged full-bore fracturing sliding sleeve further includes an opening mechanism; the opening mechanism has a cylinder body and a positioning elastic member arranged on the cylinder body, and the diameter of the cylinder body can enable itself to pass through the inner sleeve; the length of the positioning elastic member corresponds to the predetermined length of the positioning groove, so that the opening mechanism can open the positioning elastic member when reaching the positioning groove, thereby embedding the positioning elastic member of the opening mechanism into the positioning groove; the recess is an annular recess; When a plurality of the infinite staged full-bore fracturing sliding sleeves are connected in series, different infinite staged full-bore fracturing sliding sleeves have positioning grooves with different lengths, and the longer the positioning groove of the infinite staged full-bore fracturing sliding sleeve located lower in the well; one infinite staged full-bore fracturing sliding sleeve corresponds to one opening mechanism, and the length of the positioning elastic member of each opening mechanism corresponds to the length of the positioning groove of only one infinite staged full-bore fracturing sliding sleeve.

2. The infinitely staged full-bore fracturing sliding sleeve according to claim 1, wherein The infinite staged full-bore fracturing sliding sleeve further includes a first seal and a second seal provided between the inner sleeve and the outer cylinder body. Among them, the first seal is arranged on the outer circumference of the lower end of the inner sleeve, and the second seal is arranged on the outer circumference of the upper end of the inner sleeve.

3. The infinitely graded full-bore fracturing sliding sleeve according to claim 1, wherein The opening mechanism is made of soluble alloy.

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