Drilling-free grading cementing device and pipe string

Abstract

The invention relates to the technical field of drilling, well completion and well cementation of petroleum and natural gas wells, in particular to a drilling-free graded cementing device and a pipe string, and aims to solve the problems of sealing loss and drill jamming during drilling. The drilling-free graded cementing device comprises a body, a closing sleeve, an opening sleeve, a hollow rubber plug, a flexible plug, a gravity plug and a closing plug, the flexible plug can be inserted into the hollow rubber plug to block the first-stage cementing circulation channel, and the flexible plug and the hollow rubber plug move downwards at the same time; the gravity plug can be inserted into the opening sleeve to open the second-stage cementing circulating channel; the closing plug can be inserted into the opening sleeve to block the second-stage cementing circulation channel, and the closing plug, the opening sleeve and the gravity plug move downwards at the same time. Separation is completed in a falling mode, the full bore can be achieved without drilling, it is avoided that a cement sheath cracks due to vibration of a pipe string in the drilling process, sealing loss is caused, and accidents are caused by drill jamming, the integrity of a shaft is protected, the construction process is simplified, and the construction time is saved.

Description

Technical Field

[0001] This invention relates to the field of drilling, completion and cementing technology for oil and gas wells, and particularly to a drilling-free staged cementing device and tubing string. Background Technology

[0002] Every year, nearly a thousand wells in China's onshore oilfields use staged cementing. Traditional mechanical staged cementing tools require a small drilling rig to remove the tool's accessories after staged cementing to achieve full borehole ducting and facilitate subsequent operations. However, the vibration of the tubing string during drilling can cause micro-cracks in the cement sheath at the tool location, and the sealing sleeve can easily deform, leading to seal failure and affecting wellbore integrity and service life. Furthermore, stuck pipe can easily occur during drilling, causing accidents, extending the operation cycle, and resulting in economic losses. Summary of the Invention

[0003] The purpose of this invention is to provide a drill-free graded cement injector and pipe string to solve the problems of loss of seal and stuck drill during drilling.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0005] A drill-free graded cement injector includes a body, a closing sleeve, an opening sleeve, a hollow rubber plug, and a flexible plug, a gravity plug, and a closing plug that are sequentially inserted.

[0006] The flexible plug can be inserted into the hollow rubber plug to block the first-stage cement injection circulation channel, and moves downwards simultaneously with the hollow rubber plug;

[0007] The gravity plug can be inserted into the opening sleeve to open the second-stage cement injection circulation channel;

[0008] The closing plug can be inserted into the opening sleeve to block the second-stage cement injection circulation channel, and moves downwards simultaneously with the opening sleeve and the gravity plug.

[0009] Furthermore, the drill-free graded cement injector also includes an opening sleeve pin, the closing sleeve is inserted into the body, the opening sleeve is inserted into the closing sleeve, and the opening sleeve pin is inserted into both the opening sleeve and the closing sleeve;

[0010] A first circulation hole is provided on the side wall of the main body, a second circulation hole is provided on the side wall of the closing sleeve, and a third circulation hole is provided on the side wall of the opening sleeve.

[0011] In the initial state, the first circulation hole is connected to the second circulation hole;

[0012] After the gravity plug is inserted and pressurized, the gravity plug is inserted into the opening sleeve. The opening sleeve cuts off the opening sleeve pin and moves downward to connect the first circulation hole, the second circulation hole and the third circulation hole, thus opening the second-stage cement injection circulation channel.

[0013] Furthermore, the drill-free graded cement injector also includes a closing sleeve pin, which is simultaneously inserted into the body and the closing sleeve, and the shear strength of the closing sleeve pin is greater than that of the opening sleeve pin.

[0014] After the closing plug is inserted and pressurized, the closing plug is inserted into the opening sleeve, and drives the closing sleeve to cut the closing sleeve pin;

[0015] The closing sleeve and the opening sleeve move downwards to disconnect the first circulation hole from the second circulation hole, thereby blocking the second-stage cement injection circulation channel.

[0016] Furthermore, the drill-free graded cement injector also includes a stop block, which is inserted into the side wall of the closing sleeve;

[0017] The outer side of the opening sleeve is provided with a guide groove extending along the axis. In the initial state, one end of the stop block abuts against the inner wall of the body, and the other end is inserted into the guide groove.

[0018] After the gravity plug is inserted and pressurized, the opening sleeve cuts off the opening sleeve pin and moves down to the guide groove to abut against the upper end face of the stop block.

[0019] Furthermore, the drill-free graded cement injector also includes a lower connector, which is connected to the lower end of the main body;

[0020] The contact surface between the guide groove and the stop block is an inclined surface, and a clearance groove is provided on the inner wall of the body.

[0021] After the closing plug is inserted, the closing sleeve cuts off the closing sleeve pin and moves downward to abut against the lower connector. At this time, the opening sleeve continues to move downward and pushes the stop block to move radially so that the stop block is inserted into the relief groove and disengaged from the guide groove. Subsequently, the closing plug, the opening sleeve and the gravity plug continue to move downward.

[0022] Furthermore, the drill-free graded cement injector also includes a hollow rubber plug pin and a lower connector. The lower connector is connected to the body, the hollow rubber plug is inserted into the lower connector, and the hollow rubber plug pin is inserted into both the hollow rubber plug and the lower connector.

[0023] After being pressurized, the hollow rubber stopper cuts off the hollow rubber stopper pin and causes the flexible stopper to fall simultaneously.

[0024] Furthermore, the flexible plug includes a flexible plug body and a flexible plug retaining ring, the flexible plug retaining ring being engaged with the flexible plug body;

[0025] After the flexible plug is inserted into the hollow rubber plug, the flexible plug retainer snaps simultaneously engage with both the hollow rubber plug and the flexible plug body.

[0026] Furthermore, the flexible plug also includes a flexible plug sealing ring, which is snapped onto the outside of the flexible plug body and positioned above the flexible plug retaining ring.

[0027] Furthermore, the closing plug includes a closing plug body and a closing plug retaining spring, the closing plug retaining spring being engaged with the closing plug body;

[0028] After the closing plug is inserted into the opening sleeve, the closing plug retaining spring simultaneously engages with both the closing plug body and the opening sleeve.

[0029] In another aspect of the present invention, a pipe string is proposed, comprising a float shoe, a first sleeve, a float hoop, a second sleeve, a pressure seat, a first pipe string, the aforementioned drill-free graded cement injector, and a second pipe string connected in sequence.

[0030] In summary, the technical effects achieved by this invention are as follows:

[0031] The drilling-free grading cement injector provided by this invention includes a body, a closing sleeve, an opening sleeve, a hollow rubber plug, and a flexible plug, a gravity plug, and a closing plug inserted sequentially. The flexible plug can be inserted into the hollow rubber plug to block the first-stage cement injection circulation channel and moves downwards simultaneously with the hollow rubber plug. The gravity plug can be inserted into the opening sleeve to open the second-stage cement injection circulation channel. The closing plug can be inserted into the opening sleeve to block the second-stage cement injection circulation channel and moves downwards simultaneously with the opening sleeve and the gravity plug.

[0032] The drilling-free staged cementing device provided by this invention uses a flexible plug and a hollow rubber plug to seal the first-stage cementing circulation channel under pressure. Then, a gravity plug drives an opening sleeve to open the second-stage cementing circulation channel. Finally, a closing plug drives the opening sleeve and gravity plug downward to close the second-stage cementing circulation channel and achieve full borehole clearance. This method of disengagement via a downward movement eliminates the need for drilling, preventing cracks in the cement sheath caused by pipe string vibration during drilling, which could lead to seal failure and stuck pipe accidents. It protects wellbore integrity, simplifies the construction process, and saves construction time. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of the drill-free graded cement injector provided in an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the flexible plug structure;

[0036] Figure 3 This is a schematic diagram of the gravity plug structure;

[0037] Figure 4 This is a schematic diagram of the closed plug structure;

[0038] Figure 5 A schematic diagram for closing the first-stage cement injection circulation channel;

[0039] Figure 6 A schematic diagram for opening the second-stage cement circulation channel;

[0040] Figure 7 A schematic diagram for closing the second-stage cement injection circulation channel;

[0041] Figure 8 This is a schematic diagram of the full bore structure.

[0042] Icons: 100-Body; 200-Closed sleeve; 300-Opening sleeve; 400-Hollow rubber plug; 500-Opening sleeve pin; 600-Closed sleeve pin; 700-Stop block; 800-Lower connector; 900-Hollow rubber plug pin; 1000-Upper connector; 110-First circulation hole; 120-Relief groove; 210-Second circulation hole; 310-Third circulation hole; 320-Guide groove; 10-Flexible plug; 101-Flexible plug body; 102-Flexible plug retaining ring; 103-Flexible plug sealing ring; 20-Gravity plug; 30-Closed plug; 301-Closed plug body; 302-Closed plug retaining ring. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0045] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0046] Traditional mechanical staged cementing machines require a small drill string run to remove the tool's accessories after staged cementing completion to achieve full borehole ducting and facilitate subsequent operations. However, the vibration of the tubing string during drilling can cause micro-cracks in the cement sheath at the tool location, and the sealing sleeve is prone to deformation, leading to seal failure and affecting wellbore integrity and service life. Furthermore, stuck pipe can easily occur during drilling, causing accidents, extending the work cycle, and resulting in economic losses.

[0047] In view of this, the present invention provides a drill-free tiered cement injector, comprising a body 100, a closing sleeve 200, an opening sleeve 300, a hollow rubber plug 400, and a flexible plug 10, a gravity plug 20, and a closing plug 30 inserted sequentially; the flexible plug 10 can be inserted into the hollow rubber plug 400 to block the first-stage cement injection circulation channel, and moves downwards simultaneously with the hollow rubber plug 400; the gravity plug 20 can be inserted into the opening sleeve 300 to open the second-stage cement injection circulation channel; the closing plug 30 can be inserted into the opening sleeve 300 to block the second-stage cement injection circulation channel, and moves downwards simultaneously with the opening sleeve 300 and the gravity plug 20.

[0048] The drilling-free staged cementing device provided by this invention uses the cooperation of a flexible plug 10 and a hollow rubber plug 400 to seal the first-stage cementing circulation channel under pressure. Then, a gravity plug 20 drives an opening sleeve 300 to open the second-stage cementing circulation channel. Finally, a closing plug 30 drives the opening sleeve 300 and the gravity plug 20 downward to close the second-stage cementing circulation channel and achieve full borehole clearance. This method of disengagement via a downward movement eliminates the need for drilling to achieve full borehole clearance, avoiding the risk of cement sheath cracking and seal failure caused by pipe string vibration during drilling, as well as stuck pipe accidents. It protects wellbore integrity, simplifies the construction process, and saves construction time.

[0049] The following combination Figures 1-8 The structure and shape of the drill-free graded cementing device provided in this embodiment are described in detail below:

[0050] In this embodiment, the drill-free graded cement injector includes a body 100, a closing sleeve 200, an opening sleeve 300, a hollow rubber plug 400, an opening sleeve pin 500, a closing sleeve pin 600, a stop block 700, a lower connector 800, a hollow rubber plug pin 900, and an upper connector 1000. It also includes a flexible plug 10, a gravity plug 20, and a closing plug 30 that are inserted sequentially.

[0051] In this embodiment, as Figure 1 As shown, the upper and lower ends of the body 100 are connected to the upper connector 1000 and the lower connector 800 respectively via threaded connections. The upper connector 1000 and the lower connector 800 are used to connect to the upper and lower sleeve strings, respectively. Specifically, the upper connector 1000 and the lower connector 800 are inserted into the body 100. To prevent the threaded connection from loosening, a set screw is provided. The set screw is inserted into the side wall of the body 100 and connected to the body 100. The end of the set screw abuts against the upper connector 1000 and the lower connector 800 to prevent relative rotation between the upper connector 1000 and the lower connector 800 and the body 100, which would cause the threaded connection to loosen. In addition, sealing rings are installed on the outer walls of the upper connector 1000 and the lower connector 800 to enhance the sealing performance between them and the body 100.

[0052] In this embodiment, the closing sleeve 200 is inserted into the body 100, and the closing sleeve pin 600 is inserted into both the body 100 and the closing sleeve 200; the opening sleeve 300 is inserted into the closing sleeve 200, and the opening sleeve pin 500 is inserted into both the opening sleeve 300 and the closing sleeve 200. The shear strength of the closing sleeve pin 600 is greater than that of the opening sleeve pin 500 to ensure that the opening sleeve pin 500 is sheared off first.

[0053] In this embodiment, the hollow rubber plug 400 is inserted into the lower connector 800, and the hollow rubber plug pin 900 is inserted into both the hollow rubber plug 400 and the lower connector 800. The hollow rubber plug 400 includes a rigid cylinder and a rubber sleeve fitted onto the rigid cylinder. The rubber sleeve is used to achieve a seal. The inner wall of the rigid cylinder has an annular groove for connecting with the flexible plug 10, such as... Figure 1 As shown. Meanwhile, the outer wall of the rigid cylinder is equipped with a sealing ring and a retaining spring, which are used to ensure reliable connection and sealing when closing the first-stage cement injection circulation channel.

[0054] Accordingly, in this embodiment, the flexible plug 10 includes a flexible plug body 101, a flexible plug retaining ring 102, and a flexible plug sealing ring 103, such as... Figure 2As shown. The flexible plug retainer 102 is engaged with the flexible plug body 101. After the flexible plug 10 is inserted into the hollow rubber plug 400, the flexible plug retainer 102 simultaneously engages with the annular groove on the inner wall of the hollow rubber plug 400 and the flexible plug body 101 to ensure a reliable connection and prevent them from detaching. The flexible plug sealing ring 103 is engaged with the outside of the flexible plug body 101 and positioned above the flexible plug retainer 102 to improve the sealing performance between the hollow rubber plug 400 and the flexible plug 10.

[0055] Similarly, the flexible plug body 101 includes a rigid shaft and a rubber sleeve fitted onto the rigid shaft. The rubber sleeve of the flexible plug body 101 is inserted into and abuts against the rigid cylinder of the hollow rubber plug 400 to form a reliable seal. When the flexible plug 10 and the hollow rubber plug 400 are engaged, the step on the rigid shaft of the flexible plug body 101 abuts against the step on the rigid cylinder of the hollow rubber plug 400, thereby ensuring that the flexible plug retaining ring 102 can be accurately engaged in the annular groove of the hollow rubber plug 400.

[0056] In this embodiment, the rubber sleeves of both the flexible plug 10 and the hollow rubber plug 400 are configured as bowl-shaped structures with the opening facing upwards, in order to withstand downward pressure and ensure sealing performance.

[0057] In this embodiment, after the gravity plug 20 is inserted, it is inserted into the opening sleeve 300 and abuts against the step at the lower end of the opening sleeve 300, thereby closing the opening sleeve 300.

[0058] In this embodiment, the closing plug 30 includes a closing plug body 301 and a closing plug retaining spring 302, with the retaining spring 302 engaging with the closing plug body 301. After the closing plug 30 is inserted into the opening sleeve 300, the retaining spring 302 simultaneously engages with both the closing plug body 301 and the opening sleeve 300. Figure 4 , Figure 7 As shown, the closing plug retainer 302 is engaged with the rigid spindle. The closing plug body 301 includes a rigid spindle and a rubber sleeve fitted onto the rigid spindle. Similar to the flexible plug 10, the rubber sleeve of the closing plug body 301 is configured as an upward-opening bowl-shaped structure to withstand downward pressure. After the opening head is inserted, the rubber plug is inserted into the opening sleeve 300 and forms a seal with the opening sleeve 300. At the same time, the closing plug retainer 302 engages with the annular groove on the inner wall of the opening sleeve 300 to achieve a reliable connection between the closing plug 30 and the opening sleeve 300.

[0059] Similarly, the rigid mandrel abuts against the step on the upper part of the opening sleeve 300 so that the closing plug circlip 302 is accurately engaged in the annular groove of the opening sleeve 300.

[0060] In this embodiment, a first circulation hole 110 is provided on the side wall of the main body 100, a second circulation hole 210 is provided on the side wall of the closing sleeve 200, and a third circulation hole 310 is provided on the side wall of the opening sleeve 300. Initially, the first circulation hole 110 and the second circulation hole 210 are connected. After the gravity plug 20 is inserted and pressurized, the gravity plug 20 is inserted into the opening sleeve 300. The opening sleeve 300 shears the opening sleeve pin 500 and moves downward to connect the first circulation hole 110, the second circulation hole 210, and the third circulation hole 310, thus opening the second-stage cement injection circulation channel. After the closing plug 30 is inserted and pressurized, the closing plug 30 is inserted into the opening sleeve 300 and drives the closing sleeve 200 to shear the closing sleeve pin 600. The closing sleeve 200 and the opening sleeve 300 move downward to disconnect the first circulation hole 110 from the second circulation hole 210, thereby sealing the second-stage cement injection circulation channel.

[0061] In this embodiment, the stop block 700 is inserted into the side wall of the closing sleeve 200; the outer side of the opening sleeve 300 is provided with a guide groove 320 extending axially, and the inner wall of the body 100 is provided with a clearance groove 120. In the initial state, one end of the stop block 700 abuts against the inner wall of the body 100, and the other end is inserted into the guide groove 320; after the gravity plug 20 is inserted and pressure is applied, the opening sleeve 300 shears the opening sleeve pin 500 and moves downward, and the guide groove 320 abuts against the upper end face of the stop block 700, and the abutment surface between the guide groove 320 and the stop block 700 is an inclined surface. After the closing plug 30 is engaged, the closing sleeve 200 cuts the closing sleeve pin 600 and moves downward to abut against the lower connector 800. At this time, the opening sleeve 300 continues to move downward and pushes the stop block 700 to move radially so that the stop block 700 is inserted into the relief groove 120 and disengaged from the guide groove 320. Then the closing plug 30, the opening sleeve 300 and the gravity plug 20 continue to move downward.

[0062] In this embodiment, the opening sleeve 300 and the closing sleeve 200 are clearance fit, thereby reducing the frictional resistance during the downward movement of the opening sleeve 300. A sealing ring is provided between the two to ensure sealing performance.

[0063] In this embodiment, the upper end of the closing sleeve 200 is inserted into the upper connector 1000. The inner diameter of the upper connector 1000 and the closing sleeve 200 are the same. The inner diameter of the connection between the inner wall of the upper connector 1000 and the closing sleeve 200 is 3mm larger than the inner diameter of the opening sleeve 300. That is, the wall thickness of the upper end of the opening sleeve 300 is 1.5mm. This ensures that after the closing sleeve 200 moves down a certain distance, the closing sleeve 200 and the upper connector 1000 form an annular groove with a thickness of 1.5mm. This prevents a large annular space from forming between the two, which could lead to an empty glue area and reduces the risk of jamming in subsequent operations.

[0064] In this embodiment, sealing rings are provided at each connection point as needed to ensure sealing performance. For example... Figure 1As shown, multiple sealing rings are provided on both the inner and outer walls of the closing sleeve 200 to ensure the sealing of each circulation hole in all states. Specifically, four sealing rings are provided on the outer wall of the closing sleeve 200 along the axial direction, and two sealing rings are provided on the inner wall. The hollow rubber plug 400 is also provided with sealing rings to ensure the sealing performance between it and the lower connector 800.

[0065] Based on the drilling-free graded cement injector provided in this embodiment, a pipe string is proposed, including a float shoe, a first casing, a float collar, a second casing, a pressure seat, a first pipe string, the aforementioned drilling-free graded cement injector, and a second pipe string connected in sequence. The upper connector 1000 is connected to the second pipe string, the second pipe string is connected to the wellhead, and the lower connector 800 is connected to the first pipe string.

[0066] The working process of the drill-free graded cement injection device provided in this embodiment is as follows:

[0067] After the tubing string is assembled, it is lowered to the designed position. At this time, the first-stage cementing circulation channel is open, circulating drilling fluid and injecting the first-stage cement slurry. When grouting is completed, the flexible plug 10 is inserted into the well. When the flexible plug 10 reaches the annular groove inside the hollow rubber plug 400, the flexible plug retainer 102 engages with the annular groove inside the hollow rubber plug 400 to connect with the hollow rubber plug 400 and form an integral seal. Figure 5 As shown. The circulating drilling fluid pushes the hollow rubber plug 400 to shear the hollow rubber plug pin 900, causing the hollow rubber plug 400 to disengage from the lower connector 800. The hollow rubber plug 400 and the flexible plug 10 move downward as a whole to the pressure seat. At this time, the pressure suddenly increases, which completes the pressure injection. The first-stage cementing circulation channel is blocked, and the first-stage cementing operation ends.

[0068] After the first stage of cementing is completed, a gravity plug 20 is inserted from the wellhead. The gravity plug 20 enters the well and descends to the stepped surface of the opening sleeve 300, thus forming a seal with the opening sleeve 300. Under the pressure of the drilling fluid, the opening sleeve 300 shears the opening sleeve pin 500 and descends together with the gravity plug 20 until it stops at the upper end of the guide groove 320, where it abuts against the stop block 700. At this time, the first circulation hole 110, the second circulation hole 210, and the third circulation hole 310 are aligned, connecting the inner cavity of the tubing string with the annulus outside the tubing string, establishing circulation, i.e., the second stage cementing circulation channel is opened. Figure 6 As shown.

[0069] After the first-stage cement slurry solidifies, the second-stage cement injection operation can proceed. After the second-stage cement slurry is injected, the closing plug 30 is released at the wellhead. The closing plug 30 is inserted into the well, and upon entering the opening sleeve 300, the closing plug retainer 302 engages with the annular groove inside the opening sleeve 300, connecting the closing plug 30 to the opening sleeve 300 and forming a locked seal. Under drilling fluid pressure, the closing sleeve 200 shears the closing sleeve pin 600, causing the opening sleeve 300, closing plug 30, and gravity plug 20 to move downwards together. When the lower end of the closing sleeve 200 contacts the lower connector 800, the closing sleeve 200 stops moving, the stop block 700 aligns with the relief groove 120, and the closing plug 30, opening sleeve 300, and gravity plug 20 continue to descend, causing relative movement between the inclined surface of the guide groove 320 and the inclined surface of the stop block 700. This pushes the stop block 700 radially into the relief groove 120, causing the opening sleeve 300 to disengage from the closing sleeve 200. Figure 7 As shown.

[0070] Then, by opening sleeve 300, closing plug 30, and gravity plug 20 as a whole, they can continue to descend to achieve full bore, thus achieving a drill-free removal effect. Figure 8 As shown. At this time, the stop block 700 and the lower connector 800 restrict the movement of the closing sleeve 200 in the axial direction, thereby permanently locking the closing sleeve 200 and preventing the first circulation hole 110 and the second circulation hole 210 from connecting. After the wellhead is depressurized, the cement slurry in the annulus will not flow back into the tubing string through the first circulation hole 110 and the second circulation hole 210, and the second-stage cementing operation is completed.

[0071] The drilling-free staged cementing device provided in this embodiment solves the problem of insufficient wellbore integrity caused by the need for drilling small drill strings to remove the inner core in existing staged cementing systems. Simultaneously, the flexible plug 10 is fully inserted into the hollow rubber plug 400 and self-locks to form a single unit, preventing the flexible plug 10 and the hollow rubber plug 400 from separating and becoming leaky during the slurry replacement process, thus avoiding cementing accidents. Furthermore, the closing plug 30 is integrated with the opening sleeve 300 via a snap ring, preventing the closing plug 30 from detaching and getting stuck in the tubing string during descent, thus improving reliability.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drillless staged cementer, characterized by, The device comprises a body (100), a closing sleeve (200), an opening sleeve (300), a hollow rubber plug (400), and a flexible plug (10), a gravity plug (20) and a closing plug (30) sequentially inserted; The flexible plug (10) is inserted into the hollow rubber plug (400) to block the first-stage cementing circulation channel and is lowered together with the hollow rubber plug (400); The gravity plug (20) is inserted into the opening sleeve (300) to open the second-stage cementing circulation channel; The closing plug (30) is inserted into the opening sleeve (300) to block the second-stage cementing circulation channel and is lowered together with the opening sleeve (300) and the gravity plug (20).

2. The drillless staged cementing apparatus of claim 1, wherein, The device further comprises an opening sleeve pin (500), the closing sleeve (200) is inserted into the body (100), the opening sleeve (300) is inserted into the closing sleeve (200), and the opening sleeve pin (500) is inserted into the opening sleeve (300) and the closing sleeve (200) simultaneously; The body (100) is provided with a first circulation hole (110) on the side wall, the closing sleeve (200) is provided with a second circulation hole (210) on the side wall, and the opening sleeve (300) is provided with a third circulation hole (310) on the side wall; In the initial state, the first circulation hole (110) is in communication with the second circulation hole (210); After the gravity plug (20) is inserted and pressurized, the gravity plug (20) is inserted into the opening sleeve (300), the opening sleeve (300) is cut off the opening sleeve pin (500) and is lowered to make the first circulation hole (110), the second circulation hole (210) and the third circulation hole (310) in communication, and the second-stage cementing circulation channel is opened.

3. The drillless staged cementing apparatus of claim 2, wherein, The device further comprises a closing sleeve pin (600), the closing sleeve pin (600) is inserted into the body (100) and the closing sleeve (200) simultaneously, and the shearing strength of the closing sleeve pin (600) is greater than that of the opening sleeve pin (500); After the closing plug (30) is inserted and pressurized, the closing plug (30) is inserted into the opening sleeve (300) and drives the closing sleeve (200) to cut off the closing sleeve pin (600); The closing sleeve (200) and the opening sleeve (300) are lowered to disconnect the first circulation hole (110) from the second circulation hole (210), thereby blocking the second-stage cementing circulation channel.

4. The drillless staged cementing apparatus of claim 3, wherein, The device further comprises a stop block (700), the stop block (700) is inserted into the side wall of the closing sleeve (200); The opening sleeve (300) is provided with a guide groove (320) extending in the axial direction on the outside, in the initial state, one end of the stop block (700) abuts against the inner wall of the body (100) and the other end is inserted into the guide groove (320); After the gravity plug (20) is inserted and pressurized, the opening sleeve (300) cuts off the opening sleeve pin (500) and is lowered to the guide groove (320) to abut against the upper end surface of the stop block (700).

5. The drillless staged cementing apparatus of claim 4, wherein, The lower joint (800) is connected to the lower end of the body (100); The abutting surface of the guide groove (320) and the stop block (700) is a bevel, and the inner wall of the body (100) is provided with a clearance groove (120); After the closing plug (30) is put in, the closing sleeve (200) cuts the closing sleeve pin (600) and goes down to abut against the lower joint (800), at this time, the opening sleeve (300) continues to go down and pushes the stop block (700) to move radially so that the stop block (700) is inserted into the clearance groove (120) and is separated from the guide groove (320), and then the closing plug (30), the opening sleeve (300) and the gravity plug (20) continue to go down.

6. The drillless staged cementing apparatus of claim 1, wherein, The hollow rubber plug pin (900) and the lower joint (800) are further included, the lower joint (800) is connected to the body (100), the hollow rubber plug (400) is inserted into the lower joint (800), and the hollow rubber plug pin (900) is simultaneously inserted into the hollow rubber plug (400) and the lower joint (800); After being pressurized, the hollow rubber plug (400) cuts the hollow rubber plug pin (900) and drives the flexible plug (10) to fall down at the same time.

7. The drillless staged cementing apparatus of claim 1, wherein, The flexible plug (10) includes a flexible plug body (101) and a flexible plug snap spring (102), and the flexible plug snap spring (102) is snap-connected to the flexible plug body (101). After the flexible plug (10) is inserted into the hollow rubber plug (400), the flexible plug snap spring (102) is simultaneously snap-connected to the hollow rubber plug (400) and the flexible plug body (101).

8. The drillless staged cementing apparatus of claim 7, wherein, The flexible plug (10) further includes a flexible plug sealing ring (103), which is snap-connected to the outside of the flexible plug body (101) and is arranged above the flexible plug snap spring (102).

9. The drillless staged cementing apparatus of claim 1, wherein, The closing plug (30) includes a closing plug body (301) and a closing plug snap spring (302), and the closing plug snap spring (302) is snap-connected to the closing plug body (301). After the closing plug (30) is inserted into the opening sleeve (300), the closing plug snap spring (302) is simultaneously snap-connected to the closing plug body (301) and the opening sleeve (300).

10. A tube string, characterized in that The floating shoe, the first casing, the floating collar, the second casing, the pressure seat, the first casing string, the drill-free staged cementing device according to any one of claims 1-9 and the second casing string are sequentially connected.

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