Mechanical grading cementing device, well cementation and completion pipe string and well cementation and completion method

Abstract

The invention belongs to the technical field of oil and gas development, and particularly relates to a mechanical grading cementing device, a well cementation and completion pipe string and a well cementation and completion method. The mechanical type grading cementing device comprises a body, wherein a circulating hole is formed in the side wall of the body; the closing sleeve is coaxially arranged in the body, and a communicating hole is formed in the side wall of the closing sleeve; the opening plug seat is coaxially arranged in the closing sleeve; the sliding sleeve mechanism is coaxially arranged in the body through a second shear pin, and the upper end of the sliding sleeve mechanism abuts against the lower end of the opening plug seat in the axial direction.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas development technology, specifically relating to a mechanical staged cementing device, a cementing completion string, and a cementing completion method. Background Technology

[0002] The current cementing process at the top of the screen pipe employs a string structure consisting of a guide shoe, screen pipe, blind flange, open-hole packer, differential pressure staged cement injector, and casing. During the lowering of the string, the differential pressure staged cement injector, with its open sliding sleeve, is continuously subjected to internal excitation pressure. The shear pins, under repeated impacts, are at risk of fatigue and may fracture, leading to premature hole opening. The presence of the bottom blind flange creates a dead space in the upper casing volume, generating greater excitation pressure during casing lifting or lowering deceleration compared to conventional cementing completion strings, further exacerbating the risk of premature shear pin fracture.

[0003] Due to the aforementioned risks associated with lowering the screen, strictly controlling the lowering speed has become a routine risk management measure in the cementing operation procedure at the top of the screen, which is not conducive to improving the efficiency of cementing and completion operations.

[0004] Therefore, there is an urgent need to invent a device that can solve the above-mentioned technical problems. Summary of the Invention

[0005] In view of the technical problems described above, the present invention aims to provide a mechanical graded cement injector that can solve at least one of the above technical problems.

[0006] The present invention also proposes a cemented well completion string that can solve at least one of the above-mentioned technical problems.

[0007] The present invention also proposes a cementing completion method that can solve at least one of the above-mentioned technical problems.

[0008] According to the present invention, a mechanical graded cement injector is provided, comprising:

[0009] The body has circulation holes on its side wall;

[0010] A closing sleeve is coaxially disposed within the body, and a connecting hole is provided on the side wall of the closing sleeve;

[0011] An opening plug seat is coaxially disposed within the closing sleeve;

[0012] A sliding sleeve mechanism is coaxially arranged within the body via a second shear pin, the upper end of which axially abuts against the lower end of the opening plug.

[0013] In one specific embodiment, the sliding sleeve mechanism is coaxially disposed within the body via a second shear pin. The lower pressure surface of the sliding sleeve mechanism is greater than the upper pressure surface, and the pressure surfaces at both ends of the sliding sleeve mechanism are opposite in direction and equal in direction to the pressure surfaces at both ends of the opening plug.

[0014] In one specific embodiment, a second ball seat is coaxially arranged within the sliding sleeve mechanism, and mutually compatible steps are provided on the outer wall of the sliding sleeve mechanism and the inner wall of the body.

[0015] In one specific embodiment, in the first state, the circulation hole is connected to the communication hole, and the opening plug seals the communication hole;

[0016] In the second state, the opening plug moves downward relative to the closing sleeve to release the closure of the communication hole;

[0017] In the third state, the closing sleeve moves downward relative to the body, thereby closing the gap between the circulation hole and the communication hole.

[0018] In one specific embodiment, in the first state, the opening plug is fixedly connected to the closing sleeve by a first shear pin, and the upper pressure surface of the opening plug is greater than the lower pressure surface.

[0019] In one specific embodiment, a closing plug seat is provided inside the closing sleeve via a third shear pin.

[0020] In one specific embodiment, a third step is provided on the inner wall of the closing sleeve for fitting with the closing plug seat.

[0021] In one specific embodiment, an upper connector is provided at the upper end of the body, and a stop is provided between the upper connector and the closing sleeve, the stop being located between the body and the closing plug seat.

[0022] In one specific embodiment, a guide groove is provided along the axial direction on the outer wall of the closing sleeve, and a guide pin is provided on the body for fitting the guide groove.

[0023] According to the present invention, a cementing completion string is also provided, comprising a mechanical staged cementing device, a packer, a shear ball seat, a screen pipe, and a guide shoe, which are coaxially connected from top to bottom.

[0024] In one specific embodiment, the shear ball seat includes:

[0025] shell;

[0026] An intermediate sleeve is coaxially disposed within the outer casing;

[0027] The first ball seat is set inside the intermediate sleeve by a fourth shear pin.

[0028] According to the present invention, a cementing completion method is also proposed, using a cementing completion string proposed according to the present invention, comprising the following steps:

[0029] Enter the well to the designated location;

[0030] A ball is thrown into the shear ball seat to compress it, causing the packer to expand and seal.

[0031] Increase the pressure until the shear ball seat returns to its original diameter;

[0032] Balls are thrown into the mechanical graded cement injector to pressurize it, thereby opening the circulation hole of the mechanical graded cement injector and performing the cement injection process.

[0033] The circulation port of the mechanical graded cement injector is closed by closing the plug.

[0034] Compared with the prior art, the advantages of this application are as follows.

[0035] This invention features a specially structured mechanical staged cement injector and a shear-type ball seat, which can effectively solve the problem of slow casing running speed in cemented well completion processes, and effectively reduce the safety risks of the casing string during the running process, improve the safety and efficiency of cemented well completion, and reduce well construction costs. Attached Figure Description

[0036] The invention will now be described with reference to the accompanying drawings.

[0037] Figure 1 A schematic diagram of an embodiment of a cemented well completion string according to the present invention is shown;

[0038] Figure 2 A schematic diagram of one embodiment of a mechanical graded cement injector according to the present invention is shown;

[0039] Figure 3 A partially enlarged schematic diagram of the mechanical graded cement injector according to the present invention is shown;

[0040] Figure 4 A schematic diagram of a shear ball seat according to the present invention is shown.

[0041] The meanings of the reference numerals in the figure are as follows:

[0042] 1. Mechanical graded cement injector; 2. Connecting tubing; 3. Packer; 4. Shear ball seat; 5. Screen tube; 6. Guide shoe;

[0043] 101. Upper connector; 102. First sealing ring; 103. Stop block; 104. Closing plug seat; 105. Third shear pin; 106. Second sealing ring; 107. Third sealing ring; 108. Closing sleeve; 109. Opening plug seat; 110. Fourth sealing ring; 111. Fifth sealing ring; 112. Circulation hole; 113. Sixth sealing ring; 114. Seventh sealing ring; 115. Eighth sealing ring; 116. First shear pin; 117. Ninth sealing ring; 118. Body; 119. Second ball seat; 120. Tenth sealing ring; 121. Second shear pin; 122. Sliding sleeve mechanism; 123. Connecting hole; 124. First step; 125. Second step; 126. Third step; 127. Guide groove; 128. Guide pin;

[0044] 41. Outer shell; 42. Compression ball; 43. Fourth shear pin; 44. First ball seat; 45. Intermediate sleeve;

[0045] 100. Complete well tubing.

[0046] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0047] The invention will now be described with reference to the accompanying drawings.

[0048] It should be noted that in this application, the direction near the wellhead after the cementing and completion string according to the present invention is described as "upper", "front" or similar terms. For example, the end of the mechanical staged cementing machine with the upper connector is the upper end of the mechanical staged cementing machine; while the direction away from the wellhead after the cementing and completion string is described as "lower", "back" or similar terms.

[0049] Figure 1 The structure of the cementing completion string 100 according to the present invention is shown. Figure 1 As shown, the cementing completion string 100 mainly includes a mechanical staged cement injector 1, a packer 3, a shear ball seat 4, a screen pipe 5, and a guide shoe 6, which are coaxially and fixedly connected from top to bottom. The mechanical staged cement injector 1, the packer 3, the shear ball seat 4, the screen pipe 5, and the guide shoe 6 are interconnected through the connecting string 2.

[0050] In this embodiment, the packer 3 is an open-hole packer, which is expanded and sealed by liquid inflation or compression of the rubber sleeve. It is lowered to the designed position, pressurized to the designed value, and then filled with liquid or compressed to expand its outer diameter, sealing the annular space between the cemented wellbore string 100 and the wellbore. The shear ball seat 4 is located below the packer 3, and the position of the packer 3 is determined according to the cementing design. The mechanical staged cement injector 1 is located above the packer 3, and its specific position is determined according to the cementing design. The shear ball seat 4 uses a ball-dropping method to achieve internal sealing of the tubing string. After the packer 3 is expanded and sealed by pressure, a new circulation channel can be established within the cemented wellbore string 100. The guide shoe 6 is located at the bottom of the cemented wellbore string 100, guiding the cemented wellbore string 100 into the well and preventing the cemented wellbore string 100 from severely scraping or inserting into the wellbore.

[0051] In this embodiment, as Figure 2 As shown, the mechanical graded cement injector 1 mainly includes a body 118, a closing sleeve 108, and an opening plug seat 109.

[0052] The main body 118 has a cylindrical shape. A circulation hole 112 is provided on the side wall of the main body 118, connecting the inner cavity of the main body 118 to the outside. The closing sleeve 108 has a cylindrical shape and is coaxially disposed inside the main body 118. A connecting hole 123 is provided on the side wall of the closing sleeve 108, connecting the inner cavity of the closing sleeve 108 to the outside. The opening plug seat 109 has a cylindrical shape and is coaxially disposed inside the closing sleeve 108.

[0053] A third sealing ring 107, a fourth sealing ring 110, and a sixth sealing ring 113 are arranged sequentially from top to bottom between the main body 118 and the closing sleeve 108. A fifth sealing ring 111 and a seventh sealing ring 114 are arranged sequentially from top to bottom between the closing sleeve 108 and the opening plug seat 109.

[0054] In the first state, the circulation hole 112 is located between the fourth sealing ring 110 and the sixth sealing ring 113, and the circulation hole 112 communicates with the connecting hole 123. The connecting hole 123 is located between the fifth sealing ring 111 and the seventh sealing ring 114. Opening the plug seat 109 closes the connecting hole 123, thereby preventing the fluid in the inner cavity of the mechanical graded cement injector 1 from flowing to the outside of the body 118 through the circulation hole 112. In the second state, opening the plug seat 109 moves downward relative to the closing sleeve 108 to release the closure of the connecting hole 123, thereby allowing the fluid in the inner cavity of the mechanical graded cement injector 1 to flow to the outside of the body 118 through the circulation hole 112, facilitating the cement injection process. In the third state, the closing sleeve 108 moves downward relative to the body 118, causing the circulation hole 112 and the connecting hole 123 to be misaligned, ultimately sealing the circulation hole 112 and the connecting hole 123, thereby preventing the fluid in the inner cavity of the mechanical graded cement injector 1 from flowing to the outside of the body 118 through the circulation hole 112.

[0055] In one specific embodiment, in the first state, the opening stopper 109 is fixedly connected to the closing sleeve 108 via the first shear pin 116, and the upper pressure surface of the opening stopper 109 is greater than the lower pressure surface. In this configuration, when the pressure difference between the upper and lower pressure surfaces of the opening stopper 109 caused by the internal pressure of the mechanical graded cement injector 1 is less than the strength of the first shear pin 116, the opening stopper 109 will not move relative to the closing sleeve 108. When the pressure difference between the upper and lower pressure surfaces of the opening stopper 109 caused by the internal pressure of the mechanical graded cement injector 1 is greater than the strength of the first shear pin 116, the first shear pin 116 is sheared, and the opening stopper 109 moves downward relative to the closing sleeve 108 until the fifth sealing ring 111 of the opening stopper 109 moves below the connecting hole 123, thereby opening the circulation hole 112 and the connecting hole 123, enabling the cement injection process.

[0056] In this embodiment, a sliding sleeve mechanism 122 is coaxially arranged within the main body 118 via a second shear pin 121. The sliding sleeve mechanism 122 has a circular shape, and its upper end axially abuts against the lower end of the opening plug seat 109. The lower pressure surface of the sliding sleeve mechanism 122 is larger than its upper pressure surface, and the pressure difference between the upper and lower ends of the sliding sleeve mechanism 122 is equal to the pressure difference between the upper and lower ends of the opening plug seat 109. Under this arrangement, the pressure difference force exerted by the internal pressure of the mechanical graded cement injector 1 on the pressure surfaces of the upper and lower ends of the opening plug seat 109 is equal in value but opposite in direction to the pressure difference force exerted on the upper and lower ends of the sliding sleeve mechanism 122. Therefore, by providing the sliding sleeve mechanism 122, premature opening of the opening plug seat 109 can be prevented.

[0057] A ninth sealing ring 117 is provided between the sliding sleeve mechanism 122 and the closing sleeve 108, and a tenth sealing ring 120 is provided between the sliding sleeve mechanism 122 and the body 118.

[0058] In this embodiment, as Figure 2 and Figure 3 As shown, a second ball seat 119 is coaxially arranged inside the sliding sleeve mechanism 122. Matching steps are provided on the outer wall of the sliding sleeve mechanism 122 and the inner wall of the body 118. Specifically, a first step 124 is provided on the outer wall of the sliding sleeve mechanism 122, and a second step 125 is provided on the inner wall of the body 118. The first step 124 is located above the second step 125. The first step 124 and the second step 125 limit the axial movement distance of the sliding sleeve mechanism 122 relative to the body 118. By pressing a ball into the second ball seat 119, the sliding sleeve mechanism 122 can be pushed downwards relative to the body 118, thus no longer axially abutting against the opening plug seat 109. This allows the opening plug seat 109 to move downwards in response to the internal pressure of the mechanical graded cement injector 1, thereby opening the circulation hole 112 and the connecting hole 123.

[0059] In this embodiment, a closing plug seat 104 is provided inside the closing sleeve 108 via a third shear pin 105. A third step 126, adapted to the closing plug seat 104, is provided on the inner wall of the closing sleeve 108, located below the closing sleeve 108. When the cementing process is completed and the circulation hole 112 needs to be closed, a closing plug is inserted into the well. This displaces the cement slurry inside the tubing. Furthermore, when the closing plug moves to axial contact with the closing plug seat 104, it pushes the closing plug seat 104 to shear the third shear pin 105, allowing the closing plug seat 104 to move downwards relative to the closing sleeve 108 until it axially contacts the third step 126. At this point, the closing plug seat 104 pushes the closing sleeve 108 downwards relative to the body 118 via the third step 126, ultimately positioning the circulation hole 112 between the third sealing ring 107 and the fourth sealing ring 110, thus closing the circulation hole 112.

[0060] In this embodiment, an upper connector 101 is provided at the upper end of the body 118, an external thread is provided at the lower end of the upper connector 101, and an internal thread is provided at the upper end of the body 118. The upper connector 101 and the body 118 are fixedly connected by a threaded connection. A first sealing ring 102 is provided between the body 118 and the upper connector 101. A stop 103 is provided between the upper connector 101 and the closing sleeve 108. When the third shearing pin 105 has not been sheared, the stop 103 is located between the body 118 and the closing plug seat 104.

[0061] In this embodiment, a guide groove 127 is provided along the axial direction on the outer wall of the closing sleeve 108, and a guide pin 128 is provided on the body 118 to be adapted to the guide groove 127. On the one hand, this prevents the closing sleeve 108 from rotating circumferentially relative to the body 118, and on the other hand, it limits the axial movement of the closing sleeve 108 relative to the body 118.

[0062] According to the present invention, the shear ball seat 4 mainly includes a shell 41, an intermediate sleeve 45 and a first ball seat 44.

[0063] like Figure 4 As shown, the outer casing 41, intermediate sleeve 45, and first ball seat 44 are all cylindrical in shape. The intermediate sleeve 45 is coaxially mounted inside the outer casing 41 via a threaded connection, and the first ball seat 44 is coaxially mounted inside the intermediate sleeve 45 via a fourth shear pin 43. By injecting a ball into the first ball seat 44 to pressurize the well casing 100, power is supplied to the packer 3. After the packer 3 completes its expansion and sealing, continued pressurization pushes the first ball seat 44 to shear the fourth shear pin 43, causing the first ball seat 44 to disengage downwards from the intermediate sleeve 45, completing the borehole clearance.

[0064] By setting the intermediate sleeve 45, the fourth shear pin 43 can be prevented from being directly installed on the outer casing 41, thereby improving the strength of the outer casing 41.

[0065] According to the present invention, a cementing completion method is also provided, using the cementing completion tubing 100 proposed according to the present invention, comprising the following steps: injecting a ball into a shear ball seat 4 to pressurize and expand the packer 3; increasing the pressure until the shear ball seat 4 restores its bore; injecting a ball into a mechanical staged cement injector 1 to pressurize and open the circulation port of the mechanical staged cement injector 1 to perform the cementing process; and closing the circulation port of the mechanical staged cement injector 1 by using a closing plug.

[0066] Specifically, a ball is injected into the first ball seat 44 of the shear ball seat 4 to pressurize and expand the packer 3. Pressure is increased until the fourth shear pin 43 of the shear ball seat 4 is sheared, the first ball seat 44 disengages from the intermediate sleeve 45, and the shear ball seat 4 returns to its normal diameter. A ball is injected into the second ball seat 119 of the mechanical graded cement injector 1 to pressurize and expand until the second shear pin 121 of the sliding sleeve mechanism 122 is sheared, causing the sliding sleeve mechanism 122 to descend. Pressurization is applied again to create a pressure difference across the axial ends of the plug seat 109, shearing the first shear pin 116, opening the plug seat 109 and causing it to move downwards relative to the closing sleeve 108, opening the circulation hole 112 and the connecting hole 123, and then the cement injection process begins. During cementing and slurry replacement, a shut-off plug is inserted. When the shut-off plug reaches the shut-off plug seat 104, the pressure inside the pipe shears off the third shear pin 105. The shut-off plug then pushes the shut-off sleeve 108 downward relative to the main body 118 through the shut-off plug seat 104, ultimately positioning the circulation hole 112 between the third sealing ring 107 and the fourth sealing ring 110, thus closing the circulation hole 112. After the cement slurry solidifies, the shut-off plug and any remaining aluminum alloy are removed from the pipe before well completion.

[0067] The expansion sealing pressure of packer 3 and the shearing pressure of the fourth shear pin 43 of shear ball seat 4 are not limited and can be adjusted according to well conditions. The opening and closing pressure of circulation hole 112 of mechanical staged cementing machine 1 is determined according to cementing design.

[0068] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mechanical graded cement injector, characterized in that, include: The body (118) has a circulation hole (112) on its side wall; A closing sleeve (108) is coaxially disposed within the body (118), and a connecting hole (123) is provided on the side wall of the closing sleeve (108); An opening plug (109) is coaxially disposed within the closing sleeve (108); A sliding sleeve mechanism (122) is coaxially arranged in the body (118) via a second shear pin (121), the upper end of the sliding sleeve mechanism (122) axially abutting the lower end of the opening plug seat (109).

2. The mechanical graded cement injector according to claim 1, characterized in that, The sliding sleeve mechanism (122) is coaxially arranged in the body (118) via the second shear pin (121). The lower pressure surface of the sliding sleeve mechanism (122) is greater than the upper pressure surface, and the pressure surfaces at both ends of the sliding sleeve mechanism (122) are opposite to and equal to the pressure surfaces at both ends of the opening plug seat (109).

3. The mechanical graded cement injector according to claim 2, characterized in that, A second ball seat (119) is coaxially arranged inside the sliding sleeve mechanism (122), and mutually compatible steps are provided on the outer wall of the sliding sleeve mechanism (122) and the inner wall of the body (118).

4. The mechanical graded cement injector according to any one of claims 1 to 3, characterized in that, In the first state, the circulation hole (112) is connected to the communication hole (123), and the opening plug (109) closes the communication hole (123); In the second state, the opening plug (109) moves downward relative to the closing sleeve (108) to release the closure of the communication hole (123); In the third state, the closing sleeve (108) moves downward relative to the body (118), thereby closing the connection between the circulation hole (112) and the communication hole (123).

5. The mechanical graded cement injector according to claim 4, characterized in that, In the first state, the opening plug seat (109) is fixedly connected to the closing sleeve (108) by the first shear pin (116), and the upper pressure surface of the opening plug seat (109) is greater than the lower pressure surface.

6. The mechanical graded cement injector according to any one of claims 1 to 3, characterized in that, A closing plug seat (104) is provided inside the closing sleeve (108) via a third shear pin (105).

7. The mechanical graded cement injector according to claim 6, characterized in that, The inner wall of the closing sleeve (108) is provided with a third step (126) for fitting with the closing plug seat (104).

8. The mechanical graded cement injector according to claim 7, characterized in that, An upper connector (101) is provided at the upper end of the body (118), and a stop (103) is provided between the upper connector (101) and the closing sleeve (108). The stop (13) is located between the body (118) and the closing plug seat (104).

9. The mechanical graded cement injector according to any one of claims 1 to 3, characterized in that, A guide groove (127) is provided along the axial direction on the outer wall of the closing sleeve (108), and a guide pin (128) is provided on the body (118) for fitting the guide groove (127).

10. A cemented well completion tubing string, characterized in that, It includes a mechanical graded cement injector (1), a packer (3), a shear ball seat (4), a screen tube (5), and a guide shoe (6) that are coaxially connected from top to bottom according to any one of claims 1 to 9.

11. The cemented well completion string according to claim 10, characterized in that, The shear ball seat (4) includes: Outer shell (41); An intermediate sleeve (45) is coaxially disposed within the outer casing (41); The first ball seat (44) is set inside the intermediate sleeve (45) by a fourth shear pin (43).

12. A cementing completion method, characterized in that, Using the cementing completion string according to claim 10 or 11 includes the following steps: Enter the well to the designated location; A ball is thrown into the shear ball seat (4) to press and compress it, so that the packer (3) completes the expansion seal; Increase the pressure until the shear ball seat (4) restores the flow path; Balls are thrown into the mechanical graded cement injector (1) to pressurize it, thereby opening the circulation hole of the mechanical graded cement injector (1) and performing the cement injection process. The circulation hole of the mechanical graded cement injector (1) is closed by closing the plug.

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