A multi-stage force-boosting staged cementer

Abstract

The application discloses a multistage force increasing type staged cementing device and relates to the technical field of oil and gas well production. The device comprises an upper joint, an outer sleeve, a compression 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. The upper joint and the lower joint are designed conventionally and are convenient for connecting with the casing string corresponding to the upper joint and the lower joint. The compression spring is matched with the balancing sleeve to realize the isolation of the internal pressure of the staged cementing device from the external pressure. The closing plug and the closing mechanism are matched to close the circulating hole after the cementing construction technology, so that the cement is prevented from returning. The supporting sleeve is used for supporting the closing structure, and the opening mechanism is used for opening the shielding of the circulating hole to form the circulating channel between the internal part of the staged cementing device and the external part. The device has special closing mechanism and opening mechanism, improves the opening and closing performance of the device in the high-pressure environment, and solves the technical bottleneck of the low success rate of the opening and closing of the staged cementing device in the cementing construction of the deep well and the ultra-deep well.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas well production, in particular to a multi-stage force-increasing type staged cementing device. BACKGROUND

[0002] With the continuous deepening of oilfield development, oil and gas exploration and development gradually turn to deep wells and ultra-deep wells with a depth of more than 5000m, the geological conditions are more complex, and the conditions such as pressure and temperature are more harsh. When the deep well and ultra-deep well is completed, cementing operation is needed, and the staged cementing device is the key tool for cementing in deep wells and ultra-deep wells. In the field application, due to the influence of high pressure in the wellbore, the circulation channel of the staged cementing device is difficult to open, and the effective channel for cementing cannot be formed. After the cementing is completed, due to the influence of the annular pressure outside the pipe and the cement slurry pressure, the cementing channel is difficult to close, and the cement slurry outside the pipe is prone to return, forming a long well section cement plug, which is difficult to process and has a long cycle.

[0003] Chinese patent CN101929318A discloses a staged cementing device, which comprises an upper joint, a working barrel, a lower joint, a rubber plug seat, a piston, a closing piston, the upper joint, the working barrel and the lower joint are sequentially fixedly connected from top to bottom, the piston is installed at the lower part of the working barrel, the closing piston is installed at the upper part of the working barrel, the upper end of the piston is overlapped with the lower end of the piston, the radial cementing hole in the middle part of the working barrel is located at the upper end of the piston, the piston and the closing piston are connected with the working barrel through the radially installed shear pin, the rubber plug seat is fixedly installed in the inner hole of the upper end part 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 barrel and the upper end surface of the lower joint form an annular space; the working barrel has a radial liquid discharge hole located at the lower end of the annular space, and the lower end of the working barrel is provided with a conical valve; the technical scheme has a conventional structure and cannot solve the above problems.

[0004] Therefore, there is an urgent need to design a new type of staged cementing device. SUMMARY

[0005] The present application provides a multi-stage force-increasing type staged cementing device to solve the problem of difficult opening and closing of the staged cementing device during cementing operation in deep wells and ultra-deep wells, which leads to construction failure.

[0006] The technical scheme of the present application is as follows: a multi-stage force-increasing type staged cementing device, which comprises 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 sleeved on the outer side of the supporting sleeve, the upper and lower ends of the two are connected with the upper joint and the connecting sleeve respectively, and a balance sleeve is slidably arranged in the annular space of the two; a compression spring is arranged on the upper side of the balance sleeve, and a circulation hole is formed in the lower part of the outer sleeve and the supporting sleeve; when the compression spring is in a normal state, the balance sleeve closes the circulation hole.

[0007] The closing mechanism comprises a supporting sleeve, a supporting sleeve and a closing sleeve, the lower end of the supporting sleeve is fixedly connected with the upper end of the closing sleeve, and the outer wall upper end of the supporting sleeve and the outer wall of the closing sleeve are both in sliding sealing connection with the inner wall of the supporting sleeve; a locking ring is sleeved on the outer wall of the closing sleeve, and a through hole is arranged on the closing sleeve and communicated with the circulating hole; at least one piston is fixedly arranged on the outer wall of the supporting sleeve, the outer wall of the piston is in sliding sealing connection with the inner wall of the supporting sleeve, the upper part of the supporting sleeve is provided with a liquid inlet channel communicated with the cavity above the supporting sleeve and the annular space of the outer sleeve supporting sleeve, and the middle part is provided with a liquid inlet hole communicated with the annular space of the outer sleeve supporting sleeve and the upper end face of the piston; the closing plug is matched with the supporting sleeve.

[0008] The opening mechanism comprises 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, and the opening sleeve is located in the inner cavity of the closing sleeve, the lower part of the opening sleeve is connected with the fixed sleeve through a shear pin, the upper part of the opening sleeve covers the through hole, and the inner diameter of the opening sleeve is smaller than the inner diameter of the supporting sleeve.

[0009] Preferably, two pistons are fixedly arranged on the outer wall of the supporting sleeve, which are a first piston and a second piston; a fixed plug is arranged between the first piston and the second piston, and the inner wall of the fixed plug is in sliding sealing connection with the outer wall of the supporting sleeve.

[0010] Preferably, a lock ring groove is arranged on the inner wall of the connecting sleeve and matched with the locking ring, when the locking ring is matched with the lock ring groove, the closing sleeve closes the circulating hole.

[0011] Preferably, a groove is arranged on the lower part of the inner wall of the balancing sleeve.

[0012] Preferably, an inner tapered surface is arranged on the upper end of the supporting sleeve, and the closing plug is matched with the inner tapered surface.

[0013] Preferably, a plurality of upper and lower lip-shaped sealing rings are arranged on the outer wall of the closing plug.

[0014] Preferably, a lower connector is connected with the lower end of the connecting sleeve.

[0015] Preferably, the upper connector and the lower connector are respectively used for connecting the upper sleeve and the lower sleeve.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] The device has special closing mechanism and opening mechanism, which improves the opening and closing performance in high pressure environment, and solves the technical bottleneck of low success rate of opening and closing of the staged cementing device in deep well and ultra-deep well cementing construction;

[0018] The device designs a multi-stage force increasing type staged cementing device closing mechanism, adopts hydraulic pressure to drive the closing sleeve to close the circulation hole, creates a multi-stage force increasing type auxiliary closing mechanism, adopts a piston to convert hydraulic pressure into mechanical thrust, and adopts multi-stage pistons to increase force in multiple stages, uses the closing plug to drive the multi-stage force increasing auxiliary to close the circulation hole in two ways, solves the problem of large closing resistance caused by the high pressure difference of the superposition of the external formation pressure and the cement slurry pressure of the closing sleeve;

[0019] The device designs a pressure balance mechanism, which uses a compression spring and a balance sleeve to isolate the internal and external pressures of the staged cementing device before the staged cementing device is opened, so that the external higher formation pressure has no pressure effect on the opening mechanism, which helps the opening mechanism to work smoothly; when the staged cementing device is closed, the balance sleeve automatically closes the circulation hole under the action of the compression spring, isolating the internal and external pressures of the staged cementing device, so that the closing mechanism works smoothly;

[0020] The device designs a closing sleeve locking mechanism, which adopts a locking ring and a locking ring groove to lock the closing sleeve, solving the problem of frequent closing sleeve downward jamming and locking failure of the existing locking mechanism. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of the present application;

[0022] Figure 2 is a schematic diagram of the closing mechanism;

[0023] Figure 3 is a schematic diagram of the opening mechanism;

[0024] Figure 4 is a structural schematic diagram of the balance sleeve.

[0025] In the figure: 1, upper connector, 2, outer sleeve, 3, compression spring, 4, closing mechanism, 401, bearing sleeve, 402, first-stage piston, 403, fixed plug, 404, second-stage piston, 405, liquid inlet channel, 406, liquid inlet hole, 5, support sleeve, 6, closing sleeve, 601, through hole, 7, balance sleeve, 701, groove, 8, circulation hole, 9, opening mechanism, 901, opening sleeve, 902, fixed sleeve, 903, locking ring, 904, shear pin, 905, locking ring groove, 10, connecting sleeve, 11, lower connector, 12, closing plug. DETAILED DESCRIPTION

[0026] The following is a further description of the present application in conjunction with the drawings and examples. Example 1

[0027] Reference Figures 1-4As shown, a multi-stage force-increasing graded cement injector includes an upper connector 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 fitted over the outside of the support sleeve 5, and the upper and lower ends of the two are respectively connected to the upper connector 1 and the connecting sleeve 10. A balance sleeve 7 is slidably arranged in the annular space between the two. A compression spring 3 is provided on the upper side of the balance 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 the normal state, the balance sleeve 7 closes the circulation hole 8.

[0028] The closing mechanism 4 includes a support sleeve 401 and a closing sleeve 6 located in the inner cavity of the support sleeve 5. The lower end of the support sleeve 401 is fixedly connected to the upper end of the closing sleeve 6, and the upper end of the outer wall of the support sleeve 401 and the outer wall of the closing sleeve 6 are slidably sealed to the inner wall of the support sleeve 5. A locking ring 903 is fitted on the outer wall of the closing sleeve 6, and a through hole 601 communicating with the circulation hole 8 is provided on the closing sleeve 6. A piston is fixed on the outer wall of the support sleeve 401, and the outer wall of the piston is slidably sealed to the inner wall of the support sleeve 5. The upper part of the support sleeve 5 is provided with a liquid inlet channel 405 that connects the upper cavity of the support sleeve 401 with the annular space of the outer sleeve 2 support sleeve 5, and the middle part is provided with a liquid inlet hole 406 that connects the annular space of the outer sleeve 2 support sleeve 5 with the upper end face of the piston. The closing plug 12 is adapted to the support sleeve 401.

[0029] The opening mechanism 9 includes an opening sleeve 901 and a fixing sleeve 902. The fixing 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 fixing sleeve 902 through a shear pin 904. Its upper part covers the through hole 601, and its inner diameter is smaller than the inner diameter of the supporting sleeve 401.

[0030] More specifically, the lower part of the inner wall of the balance sleeve 7 is provided with a groove 701, and the lower end of the connecting sleeve 10 is connected to a lower connector 11.

[0031] In use, first connect the staged cement injector to the casing on the ground. Connect the upper connector 1 to the male thread of the upper casing and the lower connector 11 to the female thread of the lower casing. Use the casing or drill pipe to lower the staged cement injector to the predetermined position in the well. Pressurize the well with a surface pump truck. Since the inner diameter of the opening sleeve 901 is the smallest, the pressure pushes the opening sleeve 901 to shear the shear pin 904, exposing the circulation hole 8. Then, the internal pressure of the staged cement injector acts on the groove 701 to push the balance sleeve 7 upward to compress the spring 3, opening the circulation hole 8 and forming a channel for drilling fluid and cement slurry. Cementing is then carried out. The cement slurry flows from the inside of the staged cement injector into the external annulus through the circulation hole 8 for cementing. After cementing is completed, the shut-off plug 12 is dropped from the ground. When the shut-off plug 12 reaches the upper part of the support sleeve 401, it blocks the channel for liquid to flow into the lower part of the shut-off plug 12. At this time, the pressure spring 3 pushes the balance sleeve 7 downward to close the circulation hole 8. Then, the shut-off plug 12 and the support sleeve 401 together push the shut-off sleeve 6 downward to close the circulation hole 8, isolating the inside and outside of this stage cement injector and preventing the cement slurry in the annulus from flowing back.

[0032] When the closing plug 12 reaches the upper part of the support sleeve 401, the liquid also enters the annulus where the compression spring 3 is located through the liquid inlet channel 405, and then enters through the liquid inlet hole 406, pushing the piston down and driving the closing sleeve 6 down together to close the circulation hole 8.

[0033] This device features a special closing mechanism 4 and an opening mechanism 9, improving its opening and closing performance under high-pressure environments and solving the technical bottleneck of low success rate of staged cement injector opening and closing during cementing operations in deep and ultra-deep wells. The device also incorporates a pressure balancing mechanism that uses a compression spring 3 in conjunction with a balancing sleeve 7 to isolate the internal and external pressures of the staged cement injector before opening. The higher external formation pressure has no pressure impact on the opening mechanism 9, facilitating its smooth operation. When the staged cement injector closes, the balancing sleeve 7 automatically closes the circulation hole 8 under the action of the compression spring 3, isolating the internal and external pressures of the staged cement injector and ensuring the smooth operation of the closing structure. Example 2

[0034] As a preferred embodiment of the present invention, this embodiment optimizes the structure of the closing mechanism 4 based on Embodiment 1, specifically as follows:

[0035] In this embodiment, two pistons, a first-stage piston 402 and a second-stage piston 404, are fixed on the outer wall of the support sleeve 401. A fixing plug 403 is provided between the first-stage piston 402 and the second-stage piston 404. The fixing plug 403 is fixed on the inner wall of the support sleeve 5, and its inner wall is slidably sealed to the outer wall of the support sleeve 401.

[0036] When the closing plug 12 reaches the upper part of the support sleeve 401, the closing plug 12 closes the channel for liquid to flow into the lower part of the closing plug 12. The liquid enters the annulus where the compression spring 3 is located through 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, driving the closing sleeve 6 downward together, and closing the circulation hole 8.

[0037] This device is designed with a multi-stage force-increasing type graded cement injector closing mechanism 4. It uses hydraulic pressure to push the closing plug 12 to drive the closing sleeve 6 to close the circulation hole 8. It innovatively adds a multi-stage force-increasing auxiliary closing mechanism 4, which uses a piston to convert hydraulic pressure into mechanical thrust and uses multi-stage pistons to increase the force in multiple stages. It uses the closing plug 12 to drive the circulation hole 8 in two ways: driving it and using multi-stage force-increasing auxiliary push. This solves the problem of high closing resistance caused by the superposition of external formation pressure and cement slurry pressure on the closing sleeve 6. Example 3

[0038] As a preferred embodiment of the present invention, this embodiment optimizes the structure of the connecting sleeve 10 based on Embodiment 1, specifically as follows:

[0039] 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 and the locking ring groove 905 are engaged, the closing sleeve 6 closes the circulation hole 8.

[0040] This device is designed with a locking mechanism for the closing sleeve 6. The locking ring 903 and the locking ring groove 905 are used to lock the closing sleeve 6, which solves the problem that the existing locking mechanism using the toothed locking method often causes the closing sleeve 6 to jam when moving downward and not to lock tightly. Example 4

[0041] As a preferred embodiment of the present invention, this embodiment further optimizes the structure of the closing mechanism 4 based on Embodiment 2, specifically as follows:

[0042] In this embodiment, the upper end of the support sleeve 401 is provided with an inner conical surface, and the closing plug 12 is engaged with the inner conical surface; this arrangement facilitates the integration of the closing plug 12 and the support sleeve 401 into one unit, which is beneficial to the smooth operation of the closing mechanism 4. Example 5

[0043] As a preferred embodiment of the present invention, this embodiment further optimizes the structure of the closing plug 12 based on embodiment four, specifically as follows:

[0044] In this embodiment, the outer wall of the shut-off plug 12 is provided with a plurality of lip-shaped sealing rings arranged side by side; the lip-shaped sealing rings can effectively improve the sealing performance of the shut-off plug 12.

[0045] This invention is not limited to the embodiments described above. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this invention, and the changed content still falls within the protection scope of this invention.

Claims

1. A multi-stage, force-increasing, graded cement injector, characterized in that: It includes an upper connector, an outer sleeve, a closing mechanism, a support sleeve, an opening mechanism, a connecting sleeve, and a closing plug. The outer sleeve is fitted over the outside of the support sleeve, and the upper and lower ends of the two are respectively connected to the upper connector and the connecting sleeve. A balance sleeve is slidably arranged in the annular space between the two. A compression spring is provided on the upper side of the balance sleeve, and a circulation hole is opened at the lower part of the outer sleeve and the support sleeve. When the compression spring is in the normal state, the balance sleeve closes the circulation hole. The closing mechanism includes a support sleeve and a closing sleeve located in the inner cavity of the support sleeve. The lower end of the support sleeve is fixedly connected to the upper end of the closing sleeve, and the upper end of the outer wall of the support sleeve and the outer wall of the closing sleeve are slidably sealed to the inner wall of the support sleeve. A locking ring is fitted on the outer wall of the closing sleeve, and a through hole communicating with the circulation hole is provided on the closing sleeve. At least one piston is fixed on the outer wall of the support sleeve, and the outer wall of the piston is slidably sealed to the inner wall of the support sleeve. The upper part of the support sleeve is provided with a liquid inlet channel communicating with the upper cavity of the support sleeve and the annular space of the outer support sleeve, and the middle part is provided with a liquid inlet hole communicating with the annular space of the outer support sleeve and the upper end face of the piston. The closing plug is adapted to the support sleeve. The opening mechanism includes an opening sleeve and a fixing sleeve. The fixing 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 fixing sleeve by a shear pin. Its upper part covers the through hole, and its inner diameter is smaller than the inner diameter of the supporting sleeve.

2. The multi-stage booster cement injector according to claim 1, characterized in that: Two pistons, a primary piston and a secondary piston, are fixed on the outer wall of the support sleeve. A fixing plug is provided between the primary piston and the secondary piston. The fixing plug is fixed on the inner wall of the support sleeve, and its inner wall is slidably sealed to the outer wall of the support sleeve.

3. The multi-stage booster cement injector according to claim 1, characterized in that: The inner wall of the connecting sleeve is provided with a locking ring groove that is adapted to the locking ring. When the locking ring is engaged with the locking ring groove, the closing sleeve closes the circulation hole.

4. The multi-stage booster cement injector according to claim 1, characterized in that: The lower part of the inner wall of the balancing sleeve is provided with a groove.

5. A multi-stage booster cement injector 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 is engaged with the inner conical surface.

6. A multi-stage booster cement injector according to claim 5, characterized in that: The outer wall of the shut-off plug is provided with several lip-shaped sealing rings arranged side by side.

7. A multi-stage, force-increasing, graded cement injector according to claim 1, characterized in that: The lower end of the connecting sleeve is connected to a lower connector.

8. A multi-stage booster cement injector according to claim 7, characterized in that: The upper connector and the lower connector are used to connect the upper sleeve and the lower sleeve, respectively.

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