Water filter pipe upper well section well cementation device

Abstract

The utility model relates to the technical field of geothermal well engineering, in particular to a water filter pipe upper well section well cementation device which comprises a sleeve, the sleeve is installed at the top of a water filter pipe, and a second plugging structure is installed between the sleeve and the water filter pipe and used for separating the interior of the sleeve and the interior of the water filter pipe and preventing slurry from sinking into the water filter pipe from the interior of the sleeve. A connector is installed at the top of the sleeve and used for being connected with a drill bit to conduct device grouting. An anti-backflow structure, a graded cementing device and a first plugging structure are sequentially arranged on the portion, close to the bottom, of the sleeve from top to bottom, the anti-backflow structure is installed in the sleeve, and the graded cementing device and the first plugging structure are connected with the sleeve through screw threads. The device is used for preventing slurry from sinking to the water filter pipe from a gap between the sleeve and the well wall of the geothermal well. According to the utility model, well cementation can be conveniently carried out on the upper well section of the water filter pipe, cement is prevented from solidifying a drill rod, and cement paste is prevented from sinking to the water filter pipe.

Description

Technical Field

[0001] The utility model relates to the technical field of geothermal well engineering, in particular to a well cementing device for an upper well section of a water filter pipe. Background Art

[0002] In recent years, with the development of geothermal resource development and utilization industry, the well construction structure of geothermal wells has been constantly updated, which has put forward more requirements for geothermal well construction technology.

[0003] When there is an oil and gas layer on the upper part of the water-intake section of the geothermal well, an abnormal pressure layer on the upper part of the water-intake section, or a drinking water aquifer on the upper part of the water-intake section, it is necessary to cement the upper part of the filter pipe. The water-intake section of the geothermal well is deep, generally 1500-3000m deep. It is difficult and risky to cement the upper part of the filter pipe. The density of cement slurry is generally 1.80g / cm 3 , which is 1.8 times that of water. A large liquid column pressure will be formed during the cementing process. If you are not careful, the aquifer in the water intake section will be squeezed out, causing the cement to sink and block the filter pipe, or the cement slurry will return to the drill pipe, causing the drill pipe to be unable to be opened and solidified.

[0004] Therefore, it is necessary to design a cementing device that improves the above problems. Utility Model Content

[0005] The utility model aims to overcome the defects of the prior art and provide a well cementing device for the upper well section of a water filter pipe.

[0006] The utility model provides a cementing device for the upper well section of a water filter pipe, comprising a casing, the casing being installed on the top of the water filter pipe, a second plugging structure being installed between the casing and the water filter pipe, for separating the casing and the inside of the water filter pipe, and preventing mud from sinking from the casing into the water filter pipe;

[0007] A joint is installed on the top of the casing for connecting with the drill bit to perform grouting of the device;

[0008] The casing is provided with an anti-backflow structure, a graded cementing device and a first plugging structure in sequence from top to bottom near the bottom. The anti-backflow structure is installed in the casing. The graded cementing device and the first plugging structure are connected to the casing through threads to prevent mud from sinking to the water filter pipe from the gap between the casing and the wall of the geothermal well.

[0009] Furthermore, the anti-backflow structure is a floating hoop.

[0010] Furthermore, an undercut is arranged on the outer side of one end of the joint, and a piston is arranged on the other end of the joint, and the outer side of the piston is sealedly connected to the inner side of the sleeve.

[0011] Furthermore, the first blocking structure includes an outer tube separator.

[0012] Furthermore, an airbag rubber bridge plug is arranged outside the outer tube separator.

[0013] Furthermore, the first blocking structure also includes a water stopper, which is installed below the outer pipe separator.

[0014] Furthermore, the second blocking structure is a blind plate joint, and the blind plate joint is located below the water stop.

[0015] Further, the water stopper is an inverted umbrella-shaped elastic structural member;

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] The utility model discloses a cementing device in which a drill pipe divides a casing into two spaces via a joint. During cementing, cement slurry injected from the drill pipe is pressed into a gap between the casing above the water filter pipe and the well wall of the geothermal well to be sealed and solidified. A second plugging structure is provided to separate the inside of the casing and the water filter pipe to prevent mud from sinking from the casing into the water filter pipe. A backflow prevention structure, a graded cementing device and a first plugging structure are provided to prevent mud from sinking from the gap between the casing and the well wall of the geothermal well to the water filter pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following drawings are only used to illustrate and explain the present invention, and are not intended to limit the scope of the present invention, wherein:

[0019] Figure 1 : A schematic diagram of the structure of the cementing device for the upper well section of the water filter pipe of the utility model;

[0020] In the figure: 1-geothermal well; 2-casing; 3-water filter pipe; 4-cementing section on the upper part of the water filter pipe; 5-joint; 6-anti-backflow structure; 7-stage cementing device; 8-external separator; 9-water stopper; 10-blind plate joint; 11-drill pipe; 12-cementing cement slurry inlet. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution, design method and advantages of the utility model clearer, the utility model is further described in detail through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0022] like Figure 1 As shown, the utility model provides a cementing device for the upper well section of a water filter pipe, comprising a casing 2, the casing 2 being installed on the top of a water filter pipe 3, a second plugging structure being installed between the casing 2 and the water filter pipe 3, for separating the casing 2 and the inside of the water filter pipe 3, and preventing mud from sinking from the casing 2 into the water filter pipe 3;

[0023] A joint 5 is installed on the top of the casing 2 for connecting with a drill bit 11 to perform grouting of the device;

[0024] The casing 2 is provided with a backflow prevention structure 6, a graded cementing device 7 and a first plugging structure in sequence from top to bottom near the bottom. The backflow prevention structure 6 is installed in the casing 2. The graded cementing device 7 and the first plugging structure are connected to the casing 2 through threads to prevent mud from sinking from the gap between the casing 2 and the wall of the geothermal well 1 to the water filter pipe 3;

[0025] The first plugging structure includes an outer tube separator 8, and an airbag rubber bridge plug is arranged outside the outer tube separator 8; the first plugging structure also includes a water stopper 9, and the water stopper 9 is installed below the outer tube separator 8;

[0026] The second blocking structure is a blind plate joint 10, and the blind plate joint 10 is located below the water stop 9, and the blind plate joint 10 is a prior art structure;

[0027] The anti-backflow structure 6 is a floating hoop; the water stopper 9 is an inverted umbrella-shaped elastic structural member; the staged cementing device 7 is provided with a bypass hole;

[0028] Among them, the outer side of one end of the joint 5 is provided with an undercut, and the other end of the joint 5 is provided with a piston, and the outer side of the piston is sealed and connected with the inner side of the casing 2; the undercut of the joint 5 is used to facilitate the installation of the casing 2 into the cementing section 4 at the upper part of the water filter pipe, and the piston is used to safely complete the cementing operation;

[0029] It should be noted that the anti-backflow structure 6 is provided with a back-pressure valve structure to prevent cement slurry from flowing back into the casing 2; the back-pressure valve structure is equivalent to a check valve, in which a spring presses against a sealing ball, so that the fluid in the casing 2 passes from top to bottom but not from bottom to top, thereby preventing cement slurry from flowing back into the casing 2 after cementing is completed;

[0030] The water stopper 9 of the present application is an inverted umbrella-shaped soft rubber structure; a bypass hole is provided on the graded cementing device 7, and the bypass hole on the graded cementing device 7 is in a closed state in the initial state, so that the inside and outside of the casing 2 are not connected. When a set pressure is applied to the casing 2, the bypass hole of the graded cementing device 7 is opened, and a circulation channel is established inside and outside the casing 2; an airbag rubber bridge plug is provided on the outside of the outer tube separator 8, and the airbag rubber bridge plug is in a closed state in the initial state, and the gap between the casing 2 and the wall of the geothermal well is unobstructed up and down. When a set fluid pressure is applied to the casing 2, the outer tube separator 8 is opened, and the airbag rubber bridge plug fits with the wall of the well to achieve the purpose of separation and water stopping; the gap between the casing 2 and the wall of the geothermal well is blocked to prevent the cement slurry from sinking to the filter pipe 3, and the opening pressure of the outer tube separator 8 is less than the opening pressure of the graded cementing device 7;

[0031] It is worth noting that the drill pipe of the cementing device of the present application divides the casing into two spaces through the joint. During cementing, the cement slurry injected from the drill pipe is pressed into the gap between the casing above the filter pipe and the wall of the geothermal well to be sealed and solidified. A second plugging structure is provided to separate the inside of the casing and the filter pipe to prevent the mud from sinking from the casing into the filter pipe. A backflow prevention structure 6, a graded cementing device 7 and a first plugging structure are provided to prevent the mud from sinking from the gap between the casing 2 and the wall of the geothermal well 1 to the filter pipe 3.

[0032] The cementing device includes a joint 5, which is installed on the top of the casing 2. An undercut is provided on the outside of one end of the joint 5, and a piston is provided on the other end of the joint 5. The undercut is used to smoothly install the casing 2 to the designed well section, and the piston is used to safely complete the cementing operation; the anti-backflow structure 6, the graded cementing device 7, the outer pipe separator 8, the water stop 9, and the blind plate joint 10 are installed in sequence from top to bottom at the bottom of the production casing 2 and are located above the water filter pipe 3. The anti-backflow structure 6 allows the fluid in the casing to pass from top to bottom but not from bottom to top, and prevents the cement slurry from flowing back into the casing after the cementing is completed; the cementing process of the cementing device:

[0033] First, when installing the casing 2, install the cementing accessories onto the casing 2 according to the above instructions;

[0034] Second, installing casing 2 into the designed well section;

[0035] Third, before cementing, connect the ground circulation pipeline and start to slowly pressurize the geothermal well 1. During the pressure rise process, open the outer pipe separator 8 and the staged cementing device 7 in sequence;

[0036] Fourth, the joint 5 is reversed to complete the release operation of the casing 2, and the casing 2 is smoothly installed in the designed well section, and the piston of the joint 5 cannot pull out the casing 2;

[0037] Fifth, cement slurry is injected from the cementing slurry inlet 12 according to the cementing design to complete the cementing;

[0038] Sixth, pull the piston and the drilling tool of the joint 5 out of the geothermal well 1;

[0039] Seventh, after the cementing cement has solidified, the cement plug and cementing accessories in the drilling and sweeping casing 2 are removed;

[0040] By adopting the above-mentioned cementing process, the cementing operation of the upper well section of the water filter pipe 3 can be safely and effectively achieved.

[0041] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A cementing device for the upper well section of a water filter pipe, characterized in that: The invention comprises a casing (2), wherein the casing (2) is installed at the top of a water filter pipe (3), and a second plugging structure is installed between the casing (2) and the water filter pipe (3) to separate the casing (2) and the inside of the water filter pipe (3) to prevent mud from sinking from the casing (2) into the water filter pipe (3); A joint (5) is installed on the top of the casing (2) for connecting with a drill bit (11) to perform grouting of the device; The casing (2) is provided with a backflow prevention structure (6), a graded cementing device (7) and a first plugging structure in sequence from top to bottom near the bottom; the backflow prevention structure (6) is installed in the casing (2); the graded cementing device (7) and the first plugging structure are connected to the casing (2) via threads, and are used to prevent mud from sinking from the gap between the casing (2) and the wall of the geothermal well (1) to the water filter pipe (3).

2. A cementing device for the upper well section of a water filter pipe according to claim 1, characterized in that: The anti-backflow structure (6) is a floating hoop.

3. A cementing device for the upper well section of a water filter pipe according to claim 1, characterized in that: An undercut is arranged on the outside of one end of the joint (5), and a piston is arranged on the other end of the joint (5), and the outside of the piston is sealedly connected to the inside of the sleeve (2).

4. A cementing device for the upper well section of a water filter pipe according to claim 1, characterized in that: The first blocking structure comprises an outer tube separator (8).

5. A cementing device for the upper well section of a water filter pipe according to claim 4, characterized in that: An airbag rubber bridge plug is arranged outside the outer tube separator (8).

6. A cementing device for the upper well section of a water filter pipe according to claim 4, characterized in that: The first blocking structure further comprises a water stopper (9), and the water stopper (9) is installed below the outer-pipe separator (8).

7. A cementing device for the upper well section of a water filter pipe according to claim 6, characterized in that: The second blocking structure is a blind plate joint (10), and the blind plate joint (10) is located below the water stop (9).

8. A cementing device for the upper well section of a water filter pipe according to claim 6, characterized in that: The water stopper (9) is an inverted umbrella-shaped elastic structural member.

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