Opening plug for graded cementing device, graded cementing device and construction method

Abstract

The invention provides an opening plug for a graded cementing device, which comprises a shell, a first accommodating cavity formed in the shell, a top cover used for blocking the first accommodating cavity and a driving mechanism, and the driving mechanism comprises a driving motor arranged in the first accommodating cavity and a driving piece arranged outside the first accommodating cavity, the driving motor is arranged on the driving part, the driving rod is arranged between the driving motor and the driving part, a switch group is arranged on the driving part, and the switch group is configured to start the driving part after entering drilling fluid and encountering water.

Description

Technical Field

[0001] The invention relates to the field of staged cementing technology, and in particular to an opening plug for a staged cementing device, a staged cementing device, and a construction method. Background Art

[0002] In cementing operations, when the formation to be sealed cannot withstand the pressure of the liquid column returned by the one-time cement slurry, a staged cementing device is required to change one-time cementing into two or more cementing operations. After completing the first-level cementing, a gravity-type opening plug is required to be inserted, which falls on the opening plug seat inside the staged cementing device by free fall, and the circulation hole of the staged cementing device is opened by holding the pressure in the pipe, thereby realizing the second-level cementing.

[0003] However, the speed of the free fall of the opening plug depends on external conditions such as the density and viscosity of the drilling fluid and the gap between the opening plug and the inner wall of the casing. According to statistics, the free fall speed of the gravity-type opening plug in the drilling fluid ranges from 20m / min to 60m / min, while the depth of the staged cementing device ranges from 2000m to 5500m. With the advancement of drilling technology, the staged cementing device may be lowered deeper. This results in that when the free fall speed of the gravity-type opening plug is slow and the staged cementing device is lowered to a deeper depth, the waiting time for the staged cementing device to open the hole may be as long as more than 120min. This poses a great challenge to the performance of the cement slurry that returns to the circulation hole above the staged cementing device in the first-level cementing. Or, in some wells, the first-level cement slurry is designed not to return through the staged cementing device. Although the safety of the opening is ensured, it will result in some well sections below the staged cementing device not being cemented, leaving a safety hazard for the integrity of the wellbore.

[0004] Therefore, it is desired in the art to provide an opening plug for a staged cementing device to solve the above technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide an opening plug for a staged cementing device, which can obtain a certain external thrust through a driving member while in free fall, thereby effectively shortening the time for the opening plug for the staged cementing device to fall to the opening plug seat inside the staged cementing device.

[0006] According to a first aspect of the present invention, there is provided an opening plug for a staged cementing device, comprising a housing, a first accommodating cavity being formed in the housing,

[0007] a top cover for sealing the first accommodating cavity, and

[0008] A driving mechanism, the driving mechanism comprising a driving motor disposed in the first accommodating chamber, a driving member disposed outside the first accommodating chamber, and a driving rod disposed between the driving motor and the driving member,

[0009] Wherein, a switch group is provided on the driving member, and the switch group is configured to start the driving member after entering into the drilling fluid and encountering water.

[0010] In one embodiment, a battery pack connected to the driving motor is disposed in the first accommodating cavity, and the switch group is connected to the battery pack via a cable.

[0011] In one embodiment, the top cover includes a first end cover connected to the outer shell and configured in a conical form, and a second end cover configured in a columnar form and arranged at an end of the first end cover away from the outer shell, wherein the size of the second end cover is not smaller than the size of the driving member.

[0012] In one embodiment, a sealing ring is provided at the junction of the housing and the first end cover.

[0013] In one embodiment, the driving member includes an impeller shaft, and a plurality of blades arranged circumferentially outside the impeller shaft, wherein each of the blades is arranged obliquely on the impeller shaft.

[0014] In one embodiment, a second accommodating chamber is provided in the housing, and the opening plug for the staged cementing device further comprises a weighting material concentrically arranged in the second accommodating chamber.

[0015] The housing is configured in a hollow cone-like form, and the weighting material has a corresponding shape capable of abutting against an inner wall of the housing.

[0016] In one embodiment, the opening plug for the staged cementing device is made of a drillable material.

[0017] According to a second aspect of the present invention, a staged cementing device is provided, comprising a staged cementing machine, an opening plug seat disposed in the staged cementing machine, and an opening plug for the staged cementing device as described above and adapted to the opening plug seat.

[0018] According to a third aspect of the present invention, there is provided a construction method, which utilizes the staged cementing device as described above, comprising the following steps:

[0019] S1. After the first-stage cementing operation of the staged cementing is completed, the staged cementing device is put into operation from the wellhead to open the plug;

[0020] S2. After the switch group enters the drilling fluid and encounters water, the battery group is activated, thereby the drive motor is used to rotate the drive member and move downward until it abuts against the opening plug seat.

[0021] In one embodiment, in step S2, the travel speed of the opening plug of the staged cementing device is 60-80 m / min.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] First, the present invention can obtain a certain external thrust through the driving member while in free fall, thereby effectively shortening the time for the opening plug of the graded cementing device to fall to the opening plug seat inside the graded cementing device. In this way, not only can the strict control of the cement slurry performance that exceeds the graded cementing device in the first-level cementing be reduced, the cost of related material use can be reduced, and the waiting time for opening holes can be reduced, bringing direct economic benefits, but also the backward construction process in which the first-level cement slurry does not return through the graded cementing device, resulting in no cement sealing of the part of the well section below the graded cementing device, resulting in safety hazards to the integrity of the wellbore can be abandoned.

[0024] Secondly, the device can increase its own downward speed by using the thrust of the driving part, thereby reducing the waiting time for opening the hole after the first-stage cementing, and also saving the cost of using additional additives to control the performance of the first-stage cementing super-return cement slurry. In addition, the materials used in this device are all drillable materials, so there is no risk of drilling out the internal accessories of the later stage cementing device. In addition, this device can be used directly without additional training when used on site. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described in detail below in conjunction with the accompanying drawings, in which:

[0026] Figure 1 The structure of the opening plug for the staged cementing device according to the present invention is schematically shown;

[0027] Figure 2 for Figure 1 Right view of;

[0028] Figure 3 The structure of the staged cementer according to the present invention is schematically shown.

[0029] In the drawings, the same reference numerals are used for the same components. The drawings are not drawn to scale. DETAILED DESCRIPTION

[0030] In order to make the technical solutions and advantages of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0031] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0032] In the present invention, unless otherwise clearly stipulated and limited, terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two elements.

[0033] For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The present invention will be further described below in conjunction with the accompanying drawings.

[0035] Figure 1 The structure of an opening plug 100 for a staged cementing device according to the present invention is schematically shown.

[0036] Figure 2 for Figure 1 Right view of .

[0037] like Figure 1 As shown, according to the first aspect of the present invention, there is provided an opening plug 100 for a staged cementing device, which mainly comprises a housing 10, a top cover for sealing the housing 10, and a driving mechanism. Preferably, a first accommodating chamber 101 is formed in the housing 10, and the driving mechanism comprises a driving motor 12 disposed in the first accommodating chamber 101, a driving member disposed outside the first driving chamber 101, and a driving rod 13 connecting the driving motor 12 and the driving member.

[0038] In one embodiment, Figure 1 and 2 As shown, a switch group 14 is provided on the driving member, and the switch group 14 has good sensitivity, so the switch group 14 can automatically start the driving member after entering the drilling fluid and encountering water, that is, the driving motor 12 is used to drive the driving member to rotate, thereby providing additional downward power for the opening plug 100 of the staged cementing device to accelerate the downward speed of the device, thereby reducing the opening waiting time of the staged water injector 201.

[0039] In one embodiment of the present invention, Figure 1As shown, a battery pack 15 is also provided in the first accommodating cavity 101. Preferably, the battery pack 15 is connected to the driving motor 12, and the driving motor 12 can be powered by the battery pack 15. In addition, the switch group 14 is also connected to the battery pack 15 through a cable, and when the switch group 14 sends a start signal to the battery pack 15, the battery pack 15 can power the driving motor 12 to provide power, further causing the driving member to rotate.

[0040] Compared with the prior art, the present invention can obtain a certain external thrust through the driving member while in free fall, thereby effectively shortening the time for the opening plug 100 of the graded cementing device to fall to the opening plug seat 202 inside the graded cementing device 201. In this way, not only can the strict control of the cement slurry performance that exceeds the graded cementing device 201 in the first-level cementing be reduced, the cost of related material use can be reduced, and the waiting time for opening holes can be reduced, bringing direct economic benefits, but also the backward construction process in which the first-level cement slurry does not return through the graded cementing device 201, resulting in a part of the well section below the graded cementing device without cement sealing, resulting in a safety hazard to the integrity of the wellbore, can be abandoned.

[0041] In one embodiment, the top cover is composed of a two-part structure, wherein the part connected to the housing 10 is the first end cover 111, and the part away from the housing 10 is the second end cover 112. Preferably, the first end cover 111 is configured as a conical structure, and the outer diameter of the first end cover 111 gradually decreases along the travel direction, while the second end cover 112 is configured as a columnar structure, and the outer diameter of the second end cover 112 is consistent with the maximum outer diameter of the first end cover 111. In addition, the outer diameter of the second end cover 112 is not less than the size of the driving member (i.e., the outer diameter of the circular surface formed by the blades 22 after rotation).

[0042] Therefore, during the diving process of the device, the fluid can diffuse outward under the action of the outer shell 10 and the top cover, thereby avoiding aggravating the impact of the drilling fluid on the driving component, providing a favorable working environment for the driving component as much as possible, further improving the power provided by the driving component, and thereby shortening the time for the device to reach the opening plug seat 202 of the graded water injector 201, thereby reducing the waiting time for the graded cement injector 201 to open the hole.

[0043] In one embodiment, Figure 1 As shown, a sealing ring 16 is provided at the joint of the housing 10 and the first end cover 111 of the end cover. In this way, the housing 10 and the end cover can have good sealing performance, and the safety of the battery pack 15 and the drive motor 12 in the first accommodating cavity 101 can be guaranteed after diving, so as to further ensure that the device can smoothly reach the opening plug seat 202 of the graded water injector 201.

[0044] In addition, when the cement opening plug 100 reaches the opening plug seat 202 of the graded water injector 201, a seal can be formed therewith through the sealing ring 16, which is beneficial to subsequent construction operations.

[0045] In one embodiment of the present invention, Figure 1 and 2 As shown, the driving member includes an impeller shaft 21 and blades 22. The impeller shaft 21 is fixedly connected to the driving rod 13, and is used to receive power transmission from the driving motor 12; a plurality of blades 22 are provided and are arranged at intervals along the circumferential direction on the outer side of the impeller shaft 21.

[0046] Preferably, there is only a small gap between the blade 22 and the end cover, so during the diving process, part of the fluid can be pushed outward through the end cover, thereby providing a relatively stable working environment for the blade 22 to ensure that the driving member can have sufficient drive to reach the open plug seat 202 of the graded water injector 201.

[0047] Preferably, each blade 22 is arranged obliquely on the impeller shaft 21, in other words, each blade 22 is arranged obliquely in the direction of rotation. Therefore, in the process of descending, the use of the obliquely arranged blades 22 can effectively reduce the resistance caused by the fluid to the blades 22, so that the device can achieve the effect of accelerating the downward movement, so as to ensure that the device can quickly reach the opening plug seat 202 of the graded water injector 201, thereby reducing the waiting time for the graded cement injector 201 to open the hole.

[0048] In one embodiment of the present invention, a second accommodating chamber 102 is provided in the housing 10, and the second accommodating chamber 102 is located below the first accommodating chamber 101. Preferably, the opening plug 100 for the staged cementing device further includes a weighting material 17 concentrically arranged in the second accommodating chamber 102, and the weighting material 17 can not only ensure that the center of gravity of the device is always downward, but also provide a certain power for the device to dive.

[0049] Preferably, the weight material 17 is usually a lead block.

[0050] In one embodiment, the housing 10 is configured in a hollow cone shape, and the weighting material 17 has a corresponding shape capable of abutting against the inner wall of the housing 10. Preferably, the outer diameter of the housing 10 gradually decreases along the advancing direction, thereby being able to effectively reduce the resistance caused by the drilling fluid thereto, so as to further increase the downward speed of the device, and under the guidance of the weighting material 17, the housing 10 can accurately reach the open plug seat 202 of the staged water injector 201.

[0051] In one embodiment of the present invention, the materials used for the opening plug 100 for the staged cementing device are all drillable materials, so there is no risk of drilling out the internal accessories of the later staged cementing device 201. Drillable materials are, for example, A12 aluminum alloy, heat-resistant polymer and lead.

[0052] Figure 3 The structure of a staged cementer 201 according to the present invention is schematically shown.

[0053] According to a second aspect of the present invention, a staged cementing device is provided, comprising a staged cementing device 201, an opening plug seat 202 disposed in the staged cementing device 201, and an opening plug 100 for the staged cementing device as described above and adapted to the opening plug seat 202.

[0054] According to a third aspect of the present invention, there is provided a construction method, which utilizes the staged cementing device as described above, comprising the following steps:

[0055] First, after the first-stage cementing operation of the staged cementing is completed, the opening plug 100 for the staged cementing device is put into the wellhead.

[0056] Then, the device is lowered normally until the switch group 14 enters the drilling fluid and encounters water to automatically activate the battery group 15, and the battery group 15 supplies power to the drive motor 121 to provide power, thereby rotating the blades 22 of the drive member and causing the device to move downward until the opening plug 100 of the staged cementing device abuts against the opening plug seat 202 in the staged cementing device 201.

[0057] Preferably, the opening plug seat 202 forms a sealing connection with the opening plug 100 for the staged cementing device through a sealing ring 16 .

[0058] Finally, pressure is applied to the pipe to open the circulation holes of the staged cementer 201 .

[0059] Preferably, the travel speed of the opening plug of the staged cementing device is 60-80 m / min.

[0060] At present, for 5-1 / 2” casing two-stage cementing, the position of the staged cementing device can usually reach 4500.00m. According to actual use statistics, using a conventional gravity-type open plug with internal lead weighting, it takes at least 120 minutes (average 37.5m / min) and up to 220 minutes (average 20.4m / min) to actually fall to the position of the staged cementing device based on the free fall speed. However, there was a well where the cement slurry was stationary for too long before the open plug reached the position of the staged cementing device. The cement slurry returned to the position of the staged cementing device due to water loss or contamination could not flow, causing the staged cementing device to be unable to complete the pressure-holding hole opening, resulting in the failure of the second-stage cementing. Later, the back-squeeze cement method could only be used to seal the second-stage annulus, but there was a leaking seal section, resulting in unqualified cementing quality.

[0061] Compared with the prior art, the advantages of the present invention are:

[0062] First, the present invention can obtain a certain external thrust through the driving member while the free fall occurs, thereby effectively shortening the time for the opening plug 100 of the graded cementing device to fall to the opening plug seat 202 inside the graded cementing device 201. In this way, not only can the strict control of the cement slurry performance that exceeds the graded cementing device 201 in the first-level cementing be reduced, the cost of using related materials can be reduced, and the waiting time for opening holes can be reduced, bringing direct economic benefits, but also the backward construction process in which the first-level cement slurry does not return to the graded cementing device 201, resulting in a part of the well section below the graded cementing device without cement sealing, leading to safety hazards to the integrity of the wellbore can be abandoned.

[0063] Secondly, the device can increase its own downward speed by using the thrust of the driving member, thereby reducing the waiting time for opening a hole after the first-level cementing, and can also save the cost of using additional additives to control the performance of the first-level cementing super-return cement slurry. In addition, the materials used in the device are all drillable materials, so there is no risk of drilling out the internal accessories of the later stage cementing device 201. In addition, the device can be used directly without additional training when used on site.

[0064] The above are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or modifications within the disclosure scope of the present invention, and such changes or modifications should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An opening plug for a staged cementing device, comprising: A housing (10), wherein a first accommodating cavity (101) is formed in the housing (10), a top cover for sealing the first accommodating cavity (101), and a driving mechanism, the driving mechanism comprising a driving motor (12) arranged in the first accommodating chamber (101), a driving member arranged outside the first accommodating chamber (101), and a driving rod (13) arranged between the driving motor (12) and the driving member, Wherein, a switch group (14) is provided on the driving member, and the switch group (14) is configured to start the driving member after entering into the drilling fluid and encountering water.

2. The opening plug for a staged cementing device according to claim 1, characterized in that: A battery pack (15) connected to the drive motor (12) is arranged in the first accommodating chamber (101), and the switch group (14) is connected to the battery pack (15) via a cable.

3. The opening plug for a staged cementing device according to claim 2, characterized in that: The top cover comprises a first end cover (111) connected to the outer shell (10) and configured in a conical form, and a second end cover (112) configured in a columnar form and arranged at an end of the first end cover (111) away from the outer shell (10), wherein the size of the second end cover (112) is not less than the size of the driving member.

4. The opening plug for a staged cementing device according to claim 3, characterized in that: A sealing ring (16) is provided at the joint between the housing (10) and the first end cover (111).

5. The opening plug for a staged cementing device according to claim 1, characterized in that: The driving member comprises an impeller shaft (21), and a plurality of blades (22) arranged outside the impeller shaft (21) in a circumferential direction, wherein each of the blades (22) is arranged obliquely on the impeller shaft (21).

6. The opening plug for a staged cementing device according to claim 5, characterized in that: A second accommodating chamber (102) is provided in the housing (10), and the opening plug for the staged cementing device further comprises a weighting material (17) arranged concentrically in the second accommodating chamber (102). The housing (10) is configured in a hollow cone-like form, and the weighting material (17) has a corresponding shape capable of abutting against an inner wall of the housing (10).

7. The opening plug for a staged cementing device according to claim 1, characterized in that: The opening plug for the staged cementing device is made of a drillable material.

8. A staged cementing device, comprising a staged cementing machine (201), an opening plug seat (202) arranged in the staged cementing machine (201), and an opening plug for the staged cementing device according to any one of claims 1 to 9 adapted to the opening plug seat (202).

9. A construction method, which utilizes the staged cementing device according to claim 9, comprising the following steps: S1. After the first-stage cementing operation of the staged cementing is completed, the staged cementing device is put into operation from the wellhead to open the plug; S2, the switch group (14) enters the drilling fluid and encounters water, activating the battery group (15), thereby causing the drive motor (12) to rotate and move downward until it abuts against the opening plug seat (202).

10. The construction method according to claim 9, characterized in that: In step S2, the travel speed of the opening plug of the staged cementing device is 60-80 m / min.

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