Automatic closing grouting device and its working process

Abstract

The present invention relates to an automatic closing grouting device and its working process. The grouting device comprises a grouting device body (14), a bypass hole (5) is arranged on the lower side of the side of the grouting device body (14), and a center tube (7) is arranged inside the grouting device body (14); the center tube (7) is connected to the inner wall of the grouting device body (14) through a center tube connector (10), and the center tube connector (10) can be disconnected to separate the center tube (7) and the grouting device body (14), and when the center tube (7) and the grouting device body (14) are separated, the center tube (7) can move to the position of the bypass hole (5) to close the bypass hole (5). The present invention provides an automatic closing grouting device and its working process that change the conventional wellhead grouting method in the drilling industry, reduce the labor intensity of workers, increase the casing lowering speed, save energy, and improve the cementing quality and construction safety.

Description

Technical Field

[0001] The invention relates to an automatic closing grouting device and a working process thereof, belonging to the technical field of prospecting. Background Art

[0002] During the completion and casing operation of oil exploration and development drilling, it is necessary to inject mud into the casing at the wellhead to ensure that the casing content is as full as possible. Generally, 3 tubes are filled at a time and 15 tubes are full. This is to solve the large pressure difference caused by the density difference between cement and mud. Before the cement solidifies, the cement returns to the casing under the action of the pressure difference to maintain the U-shaped tube effect of pressure balance. Therefore, a back pressure valve is inserted at the bottom of the casing. Therefore, during the casing lowering process, the mud in the wellbore cannot enter the casing, and grouting is required at the wellhead to maintain the pressure balance of the liquid column inside and outside the casing.

[0003] During the casing lowering process, the pump needs to be turned on for grouting every 15 minutes or so, which increases the labor intensity of the workers, affects the work time, and consumes a lot of energy. Since there is air in the casing, the wellhead will spray back mud during grouting, and the grouting pipeline is prone to freezing in cold areas or seasons. This seriously affects the casing lowering speed. If the grouting is not timely, the back pressure valve will be overturned. In severe cases, the casing may be deformed due to the large pressure difference.

[0004] Based on this, it is necessary to make necessary improvements. Summary of the invention

[0005] In view of the above-mentioned defects, the present invention aims to provide an automatic shut-off grouting device and its working process which can change the conventional wellhead grouting method in the drilling industry, reduce the labor intensity of workers, increase the casing lowering speed, save energy, and improve the cementing quality and construction safety.

[0006] To this end, the technical solution adopted by the present invention is: an automatically closed grouting device, comprising a grouting device body (14), a bypass hole (5) being arranged on the lower side of the side portion of the grouting device body (14), and a central tube (7) being arranged inside the grouting device body (14);

[0007] The central tube (7) is connected to the inner wall of the grouting device body (14) via a central tube connector (10); the central tube connector (10) can be disconnected to separate the central tube (7) and the grouting device body (14); when the central tube (7) and the grouting device body (14) are separated, the central tube (7) can move to the position of the bypass hole (5) to close the bypass hole (5).

[0008] Furthermore, corresponding ratchets (9) are provided on the inner wall of the grouting device body (14) and the outer wall of the central tube (7), and the central tube (7) can move downward in one direction through the cooperation of the ratchets (9).

[0009] Furthermore, a rubber plug (13) is provided on the upper side of the central tube (7), the lower part of the rubber plug (13) extends into the central tube (7), and the lower part of the rubber plug (13) is provided with a rubber plug locking pin (11) connected thereto, and the rubber plug locking pin (11) is located in the central tube (7) to form a blocking effect on the central tube (7) when it moves upward.

[0010] Furthermore, a ball (16) can be dropped into the central tube (7), the ball (16) being arranged on a ball seat (15), the ball seat (15) being connected to the central tube (7) via a ball seat connector (6), the ball seat connector (6) being disconnectable so that the ball (16), the ball seat (15) and the central tube (7) are separated, so that the ball (16) and the ball seat (15) fall and move into a backboard (4) located on the lower side of the grouting device body (14).

[0011] Furthermore, the bypass hole (5) forms an angle of 30-45° with the central axis of the grouting device body (14).

[0012] Furthermore, a one-way valve ball (3) is provided at the bottom of the grouting device body (14), and the one-way valve ball (3) is pressed against the one-way valve ball cap (1) via a spring (2).

[0013] Furthermore, a plurality of sealing members (8) are provided between the inner wall of the grouting device body (14) and the outer wall of the central tube (7).

[0014] The working process of the automatic closing grouting device is carried out according to the following steps:

[0015] 1) Using the pressure difference of the liquid column, a bypass hole (5) is opened to establish a liquid flow channel, so that the "U"-shaped pipe effect of the annular space outside the casing and the inner volume of the casing are in a balanced state, thereby achieving the purpose of automatic grouting;

[0016] 2) Throw the ball (16) to start the pump to hold the pressure, and then cut off the central pipe connector (10). The central pipe (7) moves downward, and the bypass hole (5) is closed. The pressure is continued to be held, and the ball seat connector (6) is cut off. The ball (16) and the ball seat (15) fall into the blue plate (4), and the conventional cementing method is returned.

[0017] The 2) step can be replaced by the following steps:

[0018] Direct cementing: the rubber plug (13) enters the central tube (7) to push the central tube (7) downward, closing the bypass hole (5) to complete cementing.

[0019] The advantages of the present invention are: 1) protecting the casing from being squeezed and damaged by the pressure difference of the liquid column; 2) reducing the labor intensity of the workers, and no grouting is required at the wellhead; 3) increasing the speed of lowering the casing; 4) no need to start the pump for grouting, saving energy and reducing the cost of drilling projects; 5) maintaining the hygiene of the drilling platform and preventing the phenomenon of mud back-spraying caused by air in the casing; 6) preventing the freezing of the low-pressure grouting pipeline in winter; 7) avoiding the occurrence of the back pressure valve being overturned due to untimely grouting during the casing lowering process.

[0020] 8) It is helpful for flushing wells when casing encounters resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention.

[0022] Figure 2 It is a structural schematic diagram of the anti-retraction mechanism of the present invention.

[0023] Figure 3 It is a structural schematic diagram of the automatic grouting state of the present invention.

[0024] Figure 4 This is a schematic diagram of the structure of the automatic closing grouting device in the closed state of the present invention.

[0025] In the figure, 1 is a one-way valve cover cap, 2 is a spring, 3 is a one-way valve ball, 4 is a blue plate, 5 is a bypass hole, 6 is a ball seat pin, 7 is a center tube, 8 is a seal, 9 is a ratchet, 10 is a center tube pin, 11 is a rubber plug locking pin, 12 is a rubber plug body, 13 is a rubber plug, 14 is a grouting device body, 15 is a ball seat, and 16 is a ball. DETAILED DESCRIPTION

[0026] The automatic closing grouting device comprises a grouting device body 14, a bypass hole 5 is arranged at the lower side of the side of the grouting device body 14, and a central tube 7 is arranged inside the grouting device body 14;

[0027] The center tube 7 is connected to the inner wall of the grouting device body 14 via a center tube connector 10. The center tube connector 10 can be disconnected to separate the center tube 7 from the grouting device body 14. When the center tube 7 is separated from the grouting device body 14, it can move to the position of the bypass hole 5 to close the bypass hole 5.

[0028] Furthermore, corresponding ratchet wheels 9 are provided on the inner wall of the grouting device body 14 and the outer wall of the central tube 7 , and the central tube 7 can move downward in one direction through the cooperation of the ratchet wheels 9 .

[0029] Furthermore, a rubber plug 13 is provided on the upper side of the central tube 7, and the lower part of the rubber plug 13 extends into the central tube 7. The lower part of the rubber plug 13 is provided with a rubber plug locking pin 11, and the rubber plug locking pin 11 is located in the central tube 7 to form a blockage when the central tube 7 moves upward.

[0030] Furthermore, a ball 16 can be put into the central tube 7, and the ball 16 is set on a ball seat 15. The ball seat 15 is connected to the central tube 7 through a ball seat connector 6. The ball seat connector 6 can be disconnected to separate the ball 16, the ball seat 15 and the central tube 7, so that the ball 16 and the ball seat 15 fall and move into the backboard 4 on the lower side of the grouting device body 14.

[0031] Furthermore, the bypass hole 5 forms an angle of 30-45° with the central axis of the grouting device body 14 .

[0032] Furthermore, a one-way valve ball 3 is provided at the bottom of the grouting device body 14 , and the one-way valve ball 3 is pressed against the one-way valve ball cap 1 through a spring 2 .

[0033] Furthermore, a plurality of sealing members 8 are provided between the inner wall of the grouting device body 14 and the outer wall of the central tube 7 .

[0034] The working process of the automatic closing grouting device is carried out according to the following steps:

[0035] 1) By using the pressure difference of the liquid column, the bypass hole 5 is opened to establish a liquid flow channel, so that the "U"-shaped pipe effect of the annular space outside the casing and the inner volume of the casing is in a balanced state, thereby achieving the purpose of automatic grouting;

[0036] 2) Throw the ball 16 and start the pump to hold the pressure, cut off the central pipe connector 10, move the central pipe 7 downward, close the bypass hole 5, continue to hold the pressure, cut off the ball seat connector 6, and the ball 16 and the ball seat 15 fall into the blue plate 4, returning to the conventional cementing method.

[0037] The 2) step can be replaced by the following steps:

[0038] Direct cementing, the rubber plug 13 enters the central pipe 7 to push the central pipe 7 downward, closes the bypass hole 5, and completes the cementing.

[0039] The present invention is further described below for a better understanding of the present invention: the present invention is designed with a bypass hole 5. During the casing lowering process, the wellbore mud automatically enters the casing through the bypass hole 5 to achieve the purpose of grouting and maintain the pressure difference balance between the inside and outside of the casing. The bypass hole 5 can be closed by throwing a ball 16 or the rubber plug 13 can be pressed to the central tube 7 of the automatic grouting device at the end of cement injection. Under the action of the casing pressure, the central tube 7 closes the bypass hole 5 to achieve the purpose of automatic grouting; at the same time, three anti-backflow structures are designed, namely 1) the central tube 7 closes the bypass hole 5 and the one-way valve ball 3 as the first anti-backflow structure; 2) the ratchet 9 stop mechanism of the central tube 7 and the grouting device body 14 is the second anti-backflow structure; 3) the reverse stop mechanism of the central tube 7 and the rubber plug 13 is the third anti-backflow structure.

[0040] The automatic closing grouting device of the present invention utilizes the pressure difference of the liquid column to open the bypass hole 5 to establish a liquid flow channel, so that the "U"-shaped tube effect of the outer annulus of the casing and the inner volume of the casing is in a balanced state, thereby achieving the purpose of automatic grouting. After the casing is lowered, the ball 16 can be thrown in to start the pump to hold the pressure to 6MPa, the center pipe connector 10 can be cut off, the center pipe 7 is moved downward, the bypass hole 5 can be closed, and the pressure can continue to be held to 10MPa, the ball seat connector 6 can be cut off, the ball 16 and the ball seat 15 can fall into the blue plate, and the conventional cementing method can be returned. The present invention can also cement directly without throwing the ball 16, the rubber plug 13 enters the center pipe 7 to push the center pipe 7 downward, close the bypass hole 5, and complete the cementing.

Claims

1. Automatically shut down the grouting device, characterized in that, It comprises a grouting device body (14), a bypass hole (5) is provided on the lower side of the side of the grouting device body (14), and a central tube (7) is provided inside the grouting device body (14); The central tube (7) is connected to the inner wall of the grouting device body (14) via a central tube connector (10); the central tube connector (10) can be disconnected to separate the central tube (7) from the grouting device body (14); when the central tube (7) and the grouting device body (14) are separated, the central tube (7) can move to the position of the bypass hole (5) to close the bypass hole (5); The inner wall of the grouting device body (14) and the outer wall of the central tube (7) are provided with corresponding ratchets (9), and the central tube (7) is caused to move downward in a unidirectional manner by the cooperation of the ratchets (9); A rubber plug (13) is arranged on the upper side of the central tube (7), the lower part of the rubber plug (13) extends into the central tube (7), and a rubber plug locking pin (11) is arranged and connected to the lower part of the rubber plug (13), and the rubber plug locking pin (11) is located in the central tube (7) to form a blocking force on the central tube (7) when it moves upward; A ball (16) can be dropped into the central tube (7), the ball (16) being arranged on a ball seat (15), the ball seat (15) being connected to the central tube (7) via a ball seat connector (6), the ball seat connector (6) being disconnectable to separate the ball (16), the ball seat (15) and the central tube (7), so that the ball (16) and the ball seat (15) fall and move into a backboard (4) located on the lower side of the grouting device body (14); A one-way valve ball (3) is provided at the bottom of the inner side of the grouting device body (14), and the one-way valve ball (3) is pressed against the one-way valve ball cap (1) via a spring (2).

2. The automatic closing grouting device according to claim 1, characterized in that: The bypass hole (5) forms an angle of 30-45° with the central axis of the grouting device body (14).

3. The automatic closing grouting device according to claim 1, characterized in that: A plurality of sealing members (8) are provided between the inner wall of the grouting device body (14) and the outer wall of the central tube (7).

4. A working process of the automatic closing grouting device according to claim 1, characterized in that: Follow these steps: 1) Using the pressure difference of the liquid column, a bypass hole (5) is opened to establish a liquid flow channel, so that the "U"-shaped pipe effect of the annular space outside the casing and the inner volume of the casing are in a balanced state, thereby achieving the purpose of automatic grouting; 2) Throw the ball (16) to start the pump to hold the pressure, and then cut off the central pipe connector (10). The central pipe (7) moves downward, and the bypass hole (5) is closed. The pressure is continued to hold, and the ball seat connector (6) is cut off. The ball (16) and the ball seat (15) fall into the backboard (4), and the conventional cementing method is returned.

5. The working process of the automatic closing grouting device according to claim 4 is characterized in that: The step 2) is replaced by the following steps: Direct cementing: the rubber plug (13) enters the central tube (7) to push the central tube (7) downward, closing the bypass hole (5) to complete cementing.

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