Multi-stage reinforcement type graded cementing device

Abstract

The invention discloses a multi-stage reinforcement type staged cementing device, which relates to the technical field of oil and gas well production, and comprises an upper joint, an outer sleeve, a pressure spring, a closing mechanism, a supporting sleeve, a balancing sleeve, a circulating hole, an opening mechanism, a connecting sleeve, a lower joint and a closing plug, and the upper joint and the lower joint are conventionally designed, so that the upper joint and the lower joint can be conveniently connected with casing strings corresponding to the upper joint and the lower joint; the pressure spring is matched with the balance sleeve to isolate the internal pressure from the external pressure of the graded cementing device; the closing plug and the closing mechanism are matched to close the circulating hole after the cementing construction technology, and cement is prevented from returning; the supporting sleeve is used for supporting the closing structure, and the opening mechanism is used for opening a shield of the circulating hole to form a circulating channel between the inside and the outside of the graded cementing device; the device is provided with a special closing mechanism and a special opening mechanism, so that the opening and closing performance of the device in a high-pressure environment is improved, and the technical bottleneck of low switching success rate of a grading cementing device in well cementation construction of a deep well and an ultra-deep well is solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well production, and in particular to a multi-stage force-enhancing graded cementing device. Background Art

[0002] With the continuous deepening of oilfield development, oil and gas exploration and development has gradually turned to deep wells and ultra-deep wells with a depth of more than 5,000 meters. The geological conditions are more complex, and the pressure, temperature and other conditions are more stringent. Cementing operations are required when deep wells and ultra-deep wells are completed. The graded cementing device is a key tool for cementing deep wells and ultra-deep wells. When used on site, due to the influence of the high pressure of the wellbore, the circulation channel of the graded cementing device is difficult to open and cannot form an effective channel for cementing. After the cementing is completed, it is difficult to close the cementing channel due to the influence of the annular pressure outside the pipe and the cement slurry pressure, which can easily cause the cement slurry outside the pipe to return and form a cement plug in a long well section. The subsequent treatment is difficult and the cycle is long.

[0003] Chinese patent CN101929318A discloses a graded cementing device, comprising an upper joint, a working cylinder, a lower joint, a plug seat, a piston, and a closing piston. The upper joint, the working cylinder, and the lower joint are fixedly connected in sequence from top to bottom, the piston is installed at the lower part of the working cylinder, the closing piston is installed at the upper part of the working cylinder, the upper end of the piston overlaps the lower end of the piston, the radial cementing hole in the middle of the working cylinder is located at the upper end of the piston, the piston and the closing piston are connected to the working cylinder through radially installed shear nails, the plug seat is fixedly installed in the inner hole of the upper end of the closing piston, the outer circle of the piston is a stepped shaft with a large upper part and a small lower part, and the outer circle of the piston, the inner hole of the working cylinder and the upper end face of the lower joint form an annulus; the working cylinder has a radial drainage hole located at the lower end of the annulus, and a conical valve is installed at the lower end of the working cylinder; the technical solution has a conventional structure and cannot solve the above problems.

[0004] Therefore, a new type of staged cementing device is urgently needed to be designed. Summary of the invention

[0005] In order to solve the problem of construction failure caused by difficulty in opening and closing a staged cementing device during cementing operations in deep wells and ultra-deep wells, the present invention provides a multi-stage force-enhancing staged cementing device.

[0006] The technical solution of the present invention is: a multi-stage force-enhancing graded cementing device, comprising an upper joint, an outer sleeve, a closing mechanism, a support sleeve, an opening mechanism, a connecting sleeve and a closing plug, wherein the outer sleeve is arranged on the outside of the support sleeve, and the upper and lower ends of the two are respectively connected to the upper joint and the connecting sleeve, and a balancing sleeve is slidably arranged in the annulus of the two; a compression spring is arranged on the upper side of the balancing sleeve, and a circulation hole is opened at the lower part of the outer sleeve and the support sleeve, and when the compression spring is in a normal state, the balancing sleeve closes the circulation hole; The closing mechanism comprises a supporting sleeve and a closing sleeve located in the inner cavity of the supporting sleeve, the lower end of the supporting sleeve is fixedly connected to the upper end of the closing sleeve, and the upper end of the outer wall of the supporting sleeve and the outer wall of the closing sleeve are both slidably and sealedly connected to the inner wall of the supporting sleeve; a locking ring is sleeved on the outer wall of the closing sleeve, and a through hole connected to the circulation hole is provided on the closing sleeve; at least one piston is fixedly provided on the outer wall of the supporting sleeve, and the outer wall of the piston is slidably and sealedly connected to the inner wall of the supporting sleeve, the upper part of the supporting sleeve is provided with a liquid inlet channel connecting the upper cavity of the supporting sleeve and the annulus of the outer sleeve supporting sleeve, and the middle part is provided with a liquid inlet hole connecting the annulus of the outer sleeve supporting sleeve and the upper end face of the piston; the closing plug is adapted to the supporting sleeve; The opening mechanism includes an opening sleeve and a fixed sleeve. The fixed sleeve is fixedly installed at the lower end of the inner cavity of the closing sleeve. The opening sleeve is located in the inner cavity of the closing sleeve. Its lower part is connected to the fixed sleeve through shear nails. Its upper part covers the through hole, and its inner diameter is smaller than the inner diameter of the supporting sleeve.

[0007] Preferably, two upper and lower pistons are fixed on the outer wall of the supporting sleeve, which are the primary piston and the secondary piston respectively; a fixing plug is provided between the primary piston and the secondary piston, and the fixing plug is fixed on the inner wall of the supporting sleeve, and its inner wall is slidingly and sealingly connected with the outer wall of the supporting sleeve.

[0008] Preferably, a locking ring groove adapted to the locking ring is provided on the inner wall of the connecting sleeve, and when the locking ring cooperates with the locking ring groove, the closing sleeve closes the circulation hole.

[0009] Preferably, a groove is provided at the lower portion of the inner wall of the balancing sleeve.

[0010] Preferably, the upper end of the supporting sleeve is provided with an inner conical surface, and the closing plug cooperates with the inner conical surface.

[0011] Preferably, a plurality of lip-shaped sealing rings arranged side by side up and down are provided on the outer wall of the closing plug.

[0012] Preferably, the lower end of the connecting sleeve is connected to a lower joint.

[0013] Preferably, the upper joint and the lower joint are used to connect the upper casing and the lower casing respectively.

[0014] Compared with the prior art, the present invention has the following advantages: The device has a special closing mechanism and an opening mechanism, which improves its opening and closing performance under high pressure environment, and solves the technical bottleneck of low opening and closing success rate of the graded cementing device in deep well and ultra-deep well cementing construction; This device designs a multi-stage force-enhancing graded cementing device closing mechanism, which uses hydraulic pressure to push the closing plug to drive the closing sleeve to close the circulation hole. An innovative multi-stage force-enhancing auxiliary closing mechanism is added, which uses a piston to convert the hydraulic pressure into a mechanical thrust, and uses a multi-stage piston for multi-stage force enhancement. The circulation hole is closed by two methods: the closing plug drives and the multi-stage force-enhancing auxiliary push, which solves the problem of large closing resistance caused by the high pressure difference between the external formation pressure of the closing sleeve and the cement slurry pressure. The device is designed with a pressure balance mechanism, which uses a compression spring and a balance sleeve to isolate the internal and external pressures of the graded cementing device before it is opened. The external higher formation pressure has no pressure effect on the opening mechanism, which helps the opening mechanism to work smoothly. When the graded cementing device is closed, the balance sleeve automatically closes the circulation hole under the action of the compression spring, isolates the internal and external pressures of the graded cementing device, and enables the closing structure to work smoothly. The device designs a closing sleeve locking mechanism, which realizes the locking of the closing sleeve by cooperating with a locking ring and a locking ring groove, thereby solving the problem that the closing sleeve often gets stuck when descending and is not locked tightly due to the existing locking mechanism using a tooth-shaped locking method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is a schematic diagram of the closing mechanism; Figure 3 A schematic diagram of the opening mechanism; Figure 4 It is a structural diagram of the balancing sleeve.

[0016] In the figure: 1, upper joint, 2, outer sleeve, 3, compression spring, 4, closing mechanism, 401, supporting sleeve, 402, first-stage piston, 403, fixing plug, 404, second-stage piston, 405, liquid inlet channel, 406, liquid inlet hole, 5, supporting sleeve, 6, closing sleeve, 601, through hole, 7, balancing sleeve, 701, groove, 8, circulation hole, 9, opening mechanism, 901, opening sleeve, 902, fixing sleeve, 903, locking ring, 904, shear pin, 905, locking ring groove, 10, connecting sleeve, 11, lower joint, 12, closing plug. DETAILED DESCRIPTION

[0017] The present invention is further described below with reference to the accompanying drawings and embodiments. Embodiment 1

[0018] Reference Figure 1-4As shown, a multi-stage force-enhancing graded cementing device includes an upper joint 1, an outer sleeve 2, a closing mechanism 4, a support sleeve 5, an opening mechanism 9, a connecting sleeve 10 and a closing plug 12. The outer sleeve 2 is arranged on the outside of the support sleeve 5, and the upper and lower ends of the two are respectively connected to the upper joint 1 and the connecting sleeve 10, and a balancing sleeve 7 is slidably arranged in the annulus of the two; a compression spring 3 is provided on the upper side of the balancing sleeve 7, and a circulation hole 8 is opened at the lower part of the outer sleeve 2 and the support sleeve 5. When the compression spring 3 is in a normal state, the balancing sleeve 7 closes the circulation hole 8.

[0019] The closing mechanism 4 includes a supporting sleeve 401 and a closing sleeve 6 located in the inner cavity of the supporting sleeve 5, the lower end of the supporting sleeve 401 is fixedly connected to the upper end of the closing sleeve 6, and the upper end of the outer wall of the supporting sleeve 401 and the outer wall of the closing sleeve 6 are both slidingly and sealingly connected to the inner wall of the supporting sleeve 5; a locking ring 903 is sleeved on the outer wall of the closing sleeve 6, and a through hole 601 connected to the circulation hole 8 is provided on the closing sleeve 6; a piston is fixedly provided on the outer wall of the supporting sleeve 401, and the outer wall of the piston is slidingly and sealingly connected to the inner wall of the supporting sleeve 5, and the upper part of the supporting sleeve 5 is provided with a liquid inlet channel 405 connecting the upper cavity of the supporting sleeve 401 and the annulus of the outer sleeve 2 and the support sleeve 5, and the middle part is provided with a liquid inlet hole 406 connecting the annulus of the outer sleeve 2 and the support sleeve 5 and the upper end face of the piston; the closing plug 12 is adapted to the supporting sleeve 401.

[0020] The opening mechanism 9 includes an opening sleeve 901 and a fixed sleeve 902. The fixed sleeve 902 is fixedly installed at the lower end of the inner cavity of the closing sleeve 6. The opening sleeve 901 is located in the inner cavity of the closing sleeve 6. Its lower part is connected to the fixed sleeve 902 through shear nails 904. Its upper part covers the through hole 601, and its inner diameter is smaller than the inner diameter of the supporting sleeve 401.

[0021] In more detail, a groove 701 is provided at the lower portion of the inner wall of the balancing sleeve 7 , and a lower joint 11 is connected to the lower end of the connecting sleeve 10 .

[0022] When in use, first connect the graded cementing device to the casing on the ground, connect the upper joint 1 to the upper casing male buckle, and connect the lower joint 11 to the lower casing female buckle. Use the casing or drill pipe to lower the graded cementing device to the predetermined position in the well. The ground pump truck pressurizes. Since the inner diameter of the opening sleeve 901 is the smallest, the pressure pushes the opening sleeve 901 to cut off the shear pin 904, exposing the circulation hole 8. Then the internal pressure of the graded cementing device acts on the groove 701 to push the balance sleeve 7 upward to compress the compression spring 3, open the circulation hole 8, and form a channel for drilling fluid and cement slurry. Carry out cementing construction, and the cement slurry flows from the inside of the graded cementing device into the external annulus through the circulation hole 8 for cementing. After cementing is completed, the closing plug 12 is dropped from the ground. When the closing plug 12 reaches the upper part of the supporting sleeve 401, it blocks the channel for the liquid to flow into the lower part of the closing plug 12. At this time, the compression spring 3 pushes the balance sleeve 7 downward to close the circulation hole 8. Then, the closing plug 12 and the supporting sleeve 401 push the closing sleeve 6 downward to close the circulation hole 8, thereby isolating the inside and outside of the graded cementing device to prevent the cement slurry in the annulus from flowing back.

[0023] When the closing plug 12 reaches the upper part of the supporting sleeve 401 , the liquid also enters the annular space where the compression spring 3 is located through the liquid inlet channel 405 , and then enters from the liquid inlet hole 406 , pushing the piston downward, and driving the closing sleeve 6 downward together, closing the circulation hole 8 .

[0024] The device has a special closing mechanism 4 and an opening mechanism 9, which improve its opening and closing performance under high-pressure environment, and solve the technical bottleneck of low success rate of opening and closing of the graded cementing device in deep well and ultra-deep well cementing construction; the device is designed with a pressure balancing mechanism, which uses the compression spring 3 and the balance sleeve 7 to isolate the internal and external pressures of the graded cementing device before the graded cementing device is opened, and the external higher formation pressure has no pressure effect on the opening mechanism 9, which helps the opening mechanism 9 to work smoothly; when the graded cementing device is closed, the balance sleeve 7 automatically closes the circulation hole 8 under the action of the compression spring 3, isolates the internal and external pressures of the graded cementing device, and enables the closing structure to work smoothly. Embodiment 2

[0025] As a preferred embodiment of the present invention, this embodiment optimizes the structure of the closing mechanism 4 on the basis of the first embodiment, specifically: In this embodiment, two upper and lower pistons are fixed on the outer wall of the supporting sleeve 401, namely the primary piston 402 and the secondary piston 404; a fixed plug 403 is provided between the primary piston 402 and the secondary piston 404, and the fixed plug 403 is fixed on the inner wall of the supporting sleeve 5, and its inner wall is slidably and sealedly connected with the outer wall of the supporting sleeve 401.

[0026] When the closing plug 12 reaches the upper part of the supporting sleeve 401, the closing plug 12 blocks the channel for the liquid to flow into the lower part of the closing plug 12. The liquid enters the annular space where the compression spring 3 is located from the liquid inlet channel 405, and then enters from the two liquid inlet holes 406 respectively, pushing the first-stage piston 402 and the second-stage piston 404 downward respectively, driving the closing sleeve 6 downward together, and closing the circulation hole 8.

[0027] The device is designed with a multi-stage force-enhancing graded cementing device closing mechanism 4, which adopts hydraulic pressure to push the closing plug 12 to drive the closing sleeve 6 to close the circulation hole 8, and innovatively adds a multi-stage force-enhancing auxiliary closing mechanism 4, which adopts a piston to convert the hydraulic pressure into mechanical thrust, and adopts a multi-stage piston for multi-stage force enhancement, and uses the closing plug 12 to drive and multi-stage force-enhancing auxiliary push to close the circulation hole 8 in two ways, thereby solving the problem of large closing resistance caused by the high pressure difference between the external formation pressure of the closing sleeve 6 and the cement slurry pressure. Embodiment 3

[0028] As a preferred embodiment of the present invention, this embodiment optimizes the structure of the connecting sleeve 10 on the basis of the first embodiment, specifically: In this embodiment, a locking ring groove 905 adapted to the locking ring 903 is provided on the inner wall of the connecting sleeve 10 . When the locking ring 903 cooperates with the locking ring groove 905 , the closing sleeve 6 closes the circulation hole 8 .

[0029] The device designs a locking mechanism for the closing sleeve 6, which realizes the locking of the closing sleeve 6 by cooperating with the locking ring 903 and the locking ring groove 905, thereby solving the problem that the closing sleeve 6 often gets stuck when descending and is not locked tightly due to the existing locking mechanism using the horse tooth locking method. Embodiment 4

[0030] As a preferred embodiment of the present invention, this embodiment further optimizes the structure of the closing mechanism 4 on the basis of the second embodiment, specifically: In this embodiment, an inner conical surface is provided at the upper end of the supporting sleeve 401, and the closing plug 12 cooperates with the inner conical surface; this arrangement facilitates the closing plug 12 and the supporting sleeve 401 to be combined into one, which is conducive to the smooth operation of the closing mechanism 4. Embodiment 5

[0031] As a preferred embodiment of the present invention, this embodiment further optimizes the structure of the closing plug 12 on the basis of the fourth embodiment, specifically: In this embodiment, a plurality of lip-shaped sealing rings arranged side by side up and down are provided on the outer wall of the closing plug 12 ; the lip-shaped sealing rings can effectively improve the sealing performance of the closing plug 12 .

[0032] The present invention is not limited to the above-mentioned embodiments. Various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention. The changed contents still fall within the protection scope of the present invention.

Claims

1. A multi-stage force-enhancing graded cementing device, characterized in that: It includes an upper joint, an outer sleeve, a closing mechanism, a supporting sleeve, an opening mechanism, a connecting sleeve and a closing plug. The outer sleeve is arranged on the outside of the supporting sleeve. The upper and lower ends of the two are respectively connected to the upper joint and the connecting sleeve. A balancing sleeve is slidably arranged in the annulus of the two. A compression spring is arranged on the upper side of the balancing sleeve. The lower parts of the outer sleeve and the supporting sleeve are provided with circulation holes. When the compression spring is in a normal state, the balancing sleeve closes the circulation hole. The closing mechanism comprises a supporting sleeve and a closing sleeve located in the inner cavity of the supporting sleeve, the lower end of the supporting sleeve is fixedly connected to the upper end of the closing sleeve, and the upper end of the outer wall of the supporting sleeve and the outer wall of the closing sleeve are both slidably and sealedly connected to the inner wall of the supporting sleeve; a locking ring is sleeved on the outer wall of the closing sleeve, and a through hole connected to the circulation hole is provided on the closing sleeve; at least one piston is fixedly provided on the outer wall of the supporting sleeve, and the outer wall of the piston is slidably and sealedly connected to the inner wall of the supporting sleeve, the upper part of the supporting sleeve is provided with a liquid inlet channel connecting the upper cavity of the supporting sleeve and the annulus of the outer sleeve supporting sleeve, and the middle part is provided with a liquid inlet hole connecting the annulus of the outer sleeve supporting sleeve and the upper end face of the piston; the closing plug is adapted to the supporting sleeve; The opening mechanism includes an opening sleeve and a fixed sleeve. The fixed sleeve is fixedly installed at the lower end of the inner cavity of the closing sleeve. The opening sleeve is located in the inner cavity of the closing sleeve. Its lower part is connected to the fixed sleeve through shear nails. Its upper part covers the through hole, and its inner diameter is smaller than the inner diameter of the supporting sleeve.

2. A multi-stage force-enhancing graded cementing device according to claim 1, characterized in that: The outer wall of the support sleeve is fixed with two upper and lower pistons, which are a primary piston and a secondary piston respectively; a fixed plug is provided between the primary piston and the secondary piston, and the fixed plug is fixed on the inner wall of the support sleeve, and its inner wall is slidably and sealingly connected with the outer wall of the support sleeve.

3. The multi-stage force-enhancing graded cementing device according to claim 1, characterized in that: A locking ring groove matched with the locking ring is provided on the inner wall of the connecting sleeve. When the locking ring is matched with the locking ring groove, the closing sleeve closes the circulation hole.

4. The multi-stage force-enhancing graded cementing device according to claim 1, characterized in that: A groove is provided at the lower part of the inner wall of the balancing sleeve.

5. The multi-stage force-enhancing graded cementing device according to claim 1, characterized in that: The upper end of the support sleeve is provided with an inner conical surface, and the closing plug cooperates with the inner conical surface.

6. The multi-stage force-enhancing graded cementing device according to claim 5, characterized in that: A plurality of lip-shaped sealing rings arranged side by side up and down are arranged on the outer wall of the closing plug.

7. The multi-stage force-enhancing graded cementing device according to claim 1, characterized in that: The lower end of the connecting sleeve is connected with a lower joint.

8. The multi-stage force-enhancing graded cementing device according to claim 7, characterized in that: The upper joint and the lower joint are used to connect the upper casing and the lower casing respectively.

Images