CN108590574A - A kind of stage cementing device with packing function - Google Patents

Abstract

The invention discloses a graded cementing device with a sealing function, comprising: a cementing device arranged between casing pipes, including an upper joint (1), a body (6) and a base pipe (10) connected in sequence The packer is sleeved outside the cementing device and includes a rubber sleeve (11). The rubber sleeve (11) is sleeved on the outside of the base pipe (10) and forms a movable wall with the outer wall of the base pipe (10). The sealed cavity (26) is filled with liquid, and the top of the sealed cavity (26) communicates with the inside of the cement injector through the liquid injection channel (23) in the base pipe (10). The liquid channel fills the sealed cavity with liquid to realize the sealing of the annulus. A graded cementing device with a sealing function of the present invention is suitable for graded well cementing. After the first stage cementing is completed, a hydraulic expansion packer is used to realize the separation and isolation of the upper and lower annular spaces of the graded cementing device.

Description

A graded cement injector with sealing function

technical field

The invention relates to a cementing device for downhole cementing, in particular to a pack-off type graded cementing device.

Background technique

After oil and gas wells are drilled, casings need to be lowered for cementing operations. The two-stage cementing technology can solve some technical problems in the cementing construction of deep and ultra-deep wells, such as large amount of cement injection at one time and long construction time. The stratum fracture pressure is low, the cement cannot return to the designed well depth, etc. The graded water injector with annular space isolation function can realize the isolation of the upper and lower annular open holes of the graded cementer after the completion of the primary cementing, and the blocking fluid The column pressure transmission can directly reduce the pressure on the formation at the bottom of the well, protect the formation and the wellbore, and can carry out the secondary cementing construction without waiting for the primary cement slurry to solidify, shortening the operation time and reducing the cementing cost.

The existing methods that can realize the isolation of the annulus during the staged cementing process are mainly divided into two forms: the first method uses the conventional staged cementing device and the packer to be used in series, and the packer is placed in the pipe string structure. Below the staged cementing device, its disadvantage is that two tools need to be operated separately, the operation is complicated, the structure is not compact, and the use is limited; the second type, the staged cementing device and the packer are designed as one, through the use of special accessories To trigger the action of the packer, some structural packers have the problem of premature expansion and sealing, and their safety and reliability are poor.

Contents of the invention

The object of the present invention is to provide a staged cementing device which is suitable for staged well cementing and can realize annular wellbore isolation during the cementing operation.

In order to achieve the above object, a concrete technical scheme of a graded cementing device with a sealing function of the present invention is as follows:

A graded cementing device with an isolation function, comprising: a cementing device, arranged between casings, including sequentially connected upper joints, a body and a base pipe; a packer, sleeved outside the cementing device, It includes a rubber sleeve, which is sleeved on the outside of the base pipe and forms a liquid-filled and inflatable sealed cavity with the outer wall of the base tube. The top of the sealed cavity passes through the liquid injection channel in the base tube and the cement injector. They are connected with each other, and the liquid injection channel is opened by pressing the cement injector to fill the sealed cavity with liquid to realize the sealing of the annulus.

The advantage of a kind of step cementing device with sealing function of the present invention is:

1) Simple and reasonable structure, easy operation and high reliability;

2) It is suitable for graded cementing. After the first grade cementing is completed, the hydraulic expansion packer is used to realize the separation and isolation of the upper and lower annular spaces of the graded cementing device;

3) After the packer expands, the pressure of the annular fluid column is cut off by the packer, reducing the influence of the fluid column on the formation pressure, effectively protecting the formation and wellbore, or avoiding the impact of formation leakage during primary cementing quality, and the secondary cementing construction can be carried out without waiting for the primary cement slurry to solidify, which effectively shortens the operation time;

4) The required accessories and the follow-up drilling operation of the accessories are consistent with the conventional graded cementing device, which improves the adaptability of the tool and does not generate additional special requirements.

Description of drawings

Fig. 1 is the structural diagram in the initial state of the graded cementing device of the present invention;

Fig. 2 is a schematic structural view of the graded cementing device of the present invention when the plug is opened and the plug seat is opened;

Fig. 3 is a schematic structural view of the staged cementing device of the present invention when the liquid injection channel of the packer is in an open state;

Fig. 4 is the schematic structural view of the stepped cementing device of the present invention when the circulation hole is in an open state;

Fig. 5 is a schematic structural view of the stepped cementing device of the present invention when the circulation hole is in a closed state;

Fig. 6 is the structural representation of opening plug among the present invention;

Fig. 7 is a schematic structural diagram of the closing plug in the present invention.

In the figure: 1. Upper joint; 2. Close plug seat; 3. First shear nail; 4. Stopper; 5. Close sleeve; 6. Body; 7. Open plug seat; 8. Second shear nail; 9. Retaining ring; 10. Base pipe; 11. Rubber cartridge; 12. Opening plug; 13. Closing plug; 21. Closing sleeve circulation hole; 22. Body circulation hole; 23. Liquid injection channel; 24. One-way valve; 25. Closing valve; 26. Cavity.

Detailed ways

In order to better understand the purpose, structure and function of the present invention, a step cementing device with isolation function of the present invention will be further described in detail in conjunction with the accompanying drawings.

As shown in Figures 1 to 7, it is a graded cementing device with a sealing function of the present invention, including a cementing device and a packer set outside the cementing device, and the cementing device is arranged on the casing Between the pipes, it includes the upper joint 1, the main body 6 and the base pipe 10 connected in sequence. The packer is sleeved on the outside of the base pipe 10 to seal off the annulus. The packer includes a rubber sleeve 11, and the rubber sleeve 11 A liquid-filled and inflatable sealed cavity 26 is formed between the outer wall of the base pipe 10 , and the top of the sealed cavity 26 communicates with the interior of the cement injector through the liquid injection channel 23 of the base pipe 10 . Wherein, the two ends of the upper joint 1 are threadedly connected with the casing and the body 6 respectively, and both ends of the body 6 are internal threads, and are respectively threaded with the upper upper joint 1 and the lower base pipe 10 through the internal threads, and the base pipe 10 The bottom of the tube communicates with the casing through external threads.

Further, a one-way valve 24 and a pressure-triggered closing valve 25 are arranged on the liquid injection channel 23 , and the one-way valve 24 is arranged upstream of the pressure-triggered closing valve 25 . That is, the pressure-triggered shut-off valve 25 is closer to the sealed cavity 26 than the one-way valve 24 . When the sealed cavity 26 is full and reaches the trigger pressure of the shut-off valve 25, the pressure triggers the shut-off valve 25 to close the liquid injection channel 23, thereby cutting off the liquid flow in the cement injector.

Further, the inner cover of the body 6 is provided with a closing sleeve 5, the side wall of the closing sleeve 5 is provided with a closing sleeve circulation hole 21, and the side wall of the body 6 is provided with a body circulation hole 22, through which the body 6 and the closing sleeve 5 are relatively The movement drives the circulation hole 22 of the body and the circulation hole 21 of the closing sleeve to move relative to each other to realize opening and closing. When the circulation hole 22 of the main body communicates with the circulation hole 21 of the closing sleeve in parallel, the inner and outer cavities of the cement injector are communicated, and then internal and external circulation can be performed. When the body circulation hole 22 is staggered from the closing sleeve circulation hole 21 and does not communicate with each other, the body circulation hole 22 on the body 6 is closed to complete the cementing operation.

Further, the bottom of the closing sleeve 5 is provided with an opening plug seat 7, and the opening plug seat 7 is fixedly connected with the closing sleeve 5 through the first scissors 8, and the side wall of the closing sleeve 5 is provided with an installation hole for installing the first scissors 8 , The liquid injection channel 23 communicates with the inner cavity of the cement injector through the installation hole. Therefore, when the opening plug 12 dropped into the cement injector freely falls to the opening plug seat 7 of the closing sleeve 5, and then pressurizes the inside of the sleeve, the opening plug seat 7 will shear off the first shear on the closing sleeve 5 under the action of pressure. The nail 8, the opening plug 12 and the opening plug seat 7 continue to move downward to drive the first shear nail 8 to leave the closing sleeve 5, and then leak out of the installation hole of the first shear nail 8 on the closing sleeve, and the liquid in the cement injector passes through the liquid injection The channel 23 enters the sealing cavity 26 between the base pipe 10 and the rubber sleeve 11 of the packer, and the sealing cavity 26 gradually expands through the injection of liquid, and the rubber sleeve 11 begins to expand and seal, and the annulus is sealed by the expansion of the rubber sleeve the goal of.

Further, the top of the closing sleeve 5 is provided with a closing plug seat 2, the closing plug seat 2 is fixedly connected with the closing sleeve 5 through the second scissors 3, and the side wall of the closing plug seat 2 is provided with an installation hole for installing the second scissors 3 .

Further, sealing rings are provided on the closing sleeve 5, the closing plug seat 2, the opening plug seat 7 and the base pipe 10 to meet various sealing requirements under different working conditions in the cement injector.

Further, a groove for accommodating the block 4 is provided on the inner wall of the body 6 . The bottom of the closing sleeve 5 is provided with a retaining ring 9, and the retaining ring 9 is connected with the internal thread of the inner wall of the closing sleeve 5 through the external thread of the outer wall.

Below in conjunction with accompanying drawing, the working process of a kind of step cementing device with sealing function of the present invention is described:

Firstly, put the staged cementing device of the present invention into the well, and use the flexible plug to replace the grout after the primary cementing is completed. After the grout is replaced in place, put the opening plug into the cementing device. After opening the plug seat 7 of the sleeve 5, continue to press the inside of the cement injector until the opening plug seat 7 is under pressure and cuts off the first shear nail 8 on the closing sleeve 5, and the opening plug and the opening plug seat 7 move downward to leak out Close the installation hole of the first shear nail 8 on the sleeve 5, so the liquid in the cement injector enters the sealing cavity 26 in the packer through the liquid injection channel 23, and the sealing cavity 26 gradually expands after the liquid is injected, and the glue The barrel 11 begins to bulge.

Then, continue to pressurize the inside of the cementing device. When the pressure of the sealing cavity 26 in the packer reaches a certain set value, trigger the pressure to trigger the closing valve 25 to close the liquid injection channel 23, and cut off the liquid in the cementing device. flow, the expansion of the packer is completed, and the sealing operation of the upper and lower annulus of the step cementing device is completed.

Then, continue to pressurize the inside of the cement injector. When the pressure reaches the set value of the opening, cut off the second shear nail 3 that controls the opening and closing of the circulation hole of the graded cement injector. At this time, the second shear nail 3 is partially sheared and the plug is closed. The seat 2 is still fixed on the body 6, and the closing sleeve 5 is separated from the body 6 and starts to move. When the closing sleeve circulation hole 21 on the closing sleeve 5 is flush with the body circulation hole 22 on the body 6, the cavity inside and outside the cementing device The body is connected, and the circulation is carried out through the opening; when the circulation is over, the secondary cementing operation is carried out according to the cementing requirements.

Use the closing plug 13 to replace the slurry until the closing plug 13 falls to the closing plug seat 2 of the cement injector, then the closing plug 13 pushes the closing plug seat 2 to move and cuts off the second shear nail 3 again, so that the closing plug seat 2 and the body 6 The stopper 4 falls into the corresponding groove of the closing plug seat 2. At this time, the closing sleeve 5 can move relative to the body 6. The circulation hole 21 of the closing sleeve and the circulation hole 22 of the body are no longer connected, and the body circulation on the body 6 is closed. Hole 22 has completed all cementing operations.

A graded cementing device with a sealing function of the present invention has a simple and reasonable structure, is easy to operate, and has high reliability; it is applicable to graded well cementing, and can realize annulus wellbore isolation in the cementing operation; and can realize a After the first-stage cementing is completed, the upper and lower annular spaces of the step-by-step cementing device are sealed; the influence of the liquid column on the formation pressure is reduced, the formation and the wellbore are effectively protected, and formation leakage during the first-stage cementing may be prevented from affecting the cementing quality, and there is no need to wait Once the primary cement slurry is solidified, the secondary cementing construction can be carried out, which effectively shortens the operation time; the required accessories and subsequent drilling operations of the accessories are consistent with the conventional graded cementing device, which improves the adaptability of the tool and does not generate additional special requirements.

The present invention has been further described above with the help of specific embodiments, but it should be understood that the specific description herein should not be construed as limiting the spirit and scope of the present invention. Various modifications made in the embodiments all belong to the protection scope of the present invention.

Claims (6)

1. A graded cementing device with a sealing function, characterized in that, comprising: The cement injector is arranged between the sleeves, including the upper joint (1), the body (6) and the base pipe (10) connected in sequence; The packer is sleeved outside the cementing device and includes a rubber sleeve (11). The rubber sleeve (11) is sleeved on the outside of the base pipe (10) and forms a filling space between the outer wall of the base pipe (10). Liquid expansion of the sealed cavity (26), the top of the sealed cavity (26) communicates with the cementing device through the liquid injection channel (23) in the base pipe (10), and the liquid injection is opened by pressing into the cementing device The channel fills the sealed cavity with liquid to seal off the annulus. 2. The graded cementing device according to claim 1, characterized in that, a one-way valve (24) and a pressure-triggered closing valve (25) are arranged in the liquid injection channel (23), and the one-way valve (24) is arranged at Pressure triggers upstream of the shutoff valve (25). 3. The graded cementing device according to claim 1, characterized in that, the inside of the body (6) is provided with a closing sleeve (5), and the side wall of the closing sleeve (5) is provided with a closing sleeve circulation hole (21 ); the side wall of the body (6) is provided with a body circulation hole (22), and the relative movement of the body (6) and the closing sleeve (5) drives the body circulation hole (22) to communicate with the closing sleeve circulation hole (21) or staggered. 4. The graded cementing device according to claim 1, characterized in that, the bottom of the closing sleeve (5) is provided with an opening plug seat (7), and the opening plug seat (7) is connected with the closing plug by the first shear nail (8). The sleeve (5) is fixedly connected, and the side wall of the closing sleeve (5) is provided with an installation hole for installing the first shear nail (8), and the liquid injection channel (23) communicates with the inner cavity of the cement injector through the installation hole. 5. The graded cementing device according to claim 4, characterized in that, the top of the closing sleeve (5) is provided with a closing plug seat (2), and the closing plug seat (2) is arranged inside the closing sleeve (5) , and the closing plug seat (2), the closing sleeve (5) and the body (6) are fixed together by the second shear nails (3), and the side wall of the closing plug seat (2) is provided with a Install the mounting holes for the second shear nail (3). 6. The graded cementing device according to claim 1, characterized in that a retaining ring (9) is arranged in the bottom of the closing sleeve (5), and the retaining ring (9) is threadedly connected with the closing sleeve (5).