Middle-deep layer geothermal buried central pipe fixing structure

Abstract

The utility model relates to the technical field of middle-deep layer geothermal buried central pipes, in particular to a fixing structure of a middle-deep layer geothermal buried central pipe. The structure comprises well cementation cement, a casing pipe, a centralizer and a central pipe which are arranged in a stratum from outside to inside, the casing pipe penetrates into the stratum, the well cementation cement is filled between the casing pipe and the well wall of the stratum, the casing pipe and the well wall are fixedly connected through the well cementation cement, stable support is provided for the casing pipe, meanwhile corrosive substances in the stratum can be isolated, and the well cementation effect is improved. The sleeve is protected from being corroded; the central pipe is installed in the casing pipe through the centralizer, the centralizer can guarantee that the central pipe and the casing pipe can be kept concentric and coaxial all the time under the action of large pressure of circulating water, and the inclination condition does not occur. The utility model can effectively solve the problems of low heat taking efficiency of the geothermal well and short service life of the central pipe caused by the fact that the central pipe and the sleeve of the geothermal well cannot be concentric and coaxial all the time.

Description

TECHNICAL FIELD

[0001] The utility model relates to middle deep layer geothermal ground -buried center tube technical field, concretely relates to a middle deep layer geothermal ground -buried center tube fixed structure. BACKGROUND

[0002] With the development and change of traditional energy industry structure, energy strategy layout has developed geothermal energy application technology as the future energy utilization key development direction. Geothermal energy is a kind of clean and stable, widely distributed renewable energy, and is considered to be able to meet the growing energy demand of future mankind. At present, geothermal energy utilization technology is developing, from the scale and popularity of geothermal development and utilization, shallow geothermal energy is limited by local geothermal resource conditions, and middle deep geothermal energy can break through this limitation and is more popular.

[0003] At present, the exploitation form of middle deep geothermal energy mainly includes multi-well exploitation form and single-well exploitation form. In single-well exploitation form, coaxial casing heat exchange is usually used. Low-temperature heat exchange medium flows into the annular cavity between the casing and the center tube. During the downward flow, the heat exchange medium continuously takes heat from the surrounding rock and soil, and the process continues until the bottom of the annular cavity between the casing and the center tube. Then the high-temperature medium after heat exchange is sent to the ground surface by the center tube. The heat exchange medium is mostly closed water circulation. The coaxial casing heat exchange can achieve "heat taking without water taking", realizing sustainable utilization of geothermal resources. However, in the coaxial casing heat exchange method, the movement state of the circulating water between the center tube and the casing of the geothermal well in the annular gap is uncontrollable. At the same time, due to the large depth of the geothermal well, the pressure of the circulating water is large, which leads to the fact that the center tube and the casing of the geothermal well cannot always be concentric and coaxial. This not only increases the movement resistance of the circulating water and increases the power loss of the circulating pump, affecting the heat taking efficiency of the geothermal well, but also affects the service life of the center tube of the geothermal well. UTILITY MODEL CONTENTS

[0004] To solve the problem of low heat taking efficiency and short service life of the center tube caused by the fact that the center tube and the casing of the geothermal well cannot always be concentric and coaxial, the utility model provides a middle deep layer geothermal ground -buried center tube fixed structure. This fixed structure is simple to construct, can save engineering cost and construction period, and can make the middle deep layer geothermal well achieve high heat taking efficiency.

[0005] To achieve the above object, the utility model discloses the following technical scheme: a middle-deep layer geothermal buried center pipe fixing structure, including the setting of cementing cement, casing, centralizer and center pipe from outside to inside in the stratum, the casing is in-depth stratum, the casing is filled with cementing cement between the well wall of stratum, and the center pipe is fixedly connected in the casing through the centralizer, the centralizer is spaced apart along the extension direction of center pipe, and the center pipe is kept concentric coaxial with the casing under the action of circulating water pressure.

[0006] The centralizer includes a centralizer casing and a centralizer fin, the inner hole of the centralizer casing is matched with the outer wall of the center pipe, and the center pipe is fixedly connected in the centralizer casing; the centralizer fin is long strip-shaped and includes a fixed end and a movable end, the fixed end is inclined upward by a predetermined angle and is uniformly distributed along the outer wall of the centralizer casing, and the fixed end is welded and connected with the centralizer casing; and the movable end is clamped and embedded on the casing.

[0007] The thickness of the centralizer casing is 3-10 mm, and the height is 150-300 mm.

[0008] The movable end of the centralizer fin is arc chamfer structure, and the thickness is 3-5 mm; and the centralizer fin of each group of centralizers is 4-6.

[0009] The predetermined angle of the centralizer fin inclined upward is 40-45° with the horizontal angle.

[0010] The casing is provided with a casing reserved groove at the connection position of the centralizer fin, the centralizer fin is clamped and embedded in the casing reserved groove, and the size of the casing reserved groove is matched with the movable end of the centralizer fin.

[0011] The centralizer is provided with multiple groups according to the site condition, and the vertical spacing of each group of centralizers is 150-400 m.

[0012] The centralizer casing is welded and connected with the outer wall of the center pipe.

[0013] Beneficial effects:

[0014] 1, the utility model effectively solves the problem that the geothermal well center pipe and casing cannot keep concentric and coaxial all the time, which causes low heat extraction efficiency of the geothermal well and short service life of the center pipe.

[0015] 2, the utility model has simple fixing structure construction, saves engineering cost and construction period, and makes the middle-deep layer geothermal well reach the purpose of high heat extraction efficiency.

[0016] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, and can be implemented according to the content of the specification, the following is the preferred embodiment of the present application and the detailed description of the drawings as follows. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0018] Figure 1 is a sectional view of the present application;

[0019] Figure 2 is a large view of the center pipe fixing structure of the present application;

[0020] Figure 3 is a sectional view of the center pipe centralizer of the present application;

[0021] Figure 4 is a plan view of the center pipe centralizer of the present application.

[0022] The meanings of the various marks in the above drawings are as follows: 1, formation; 2, well cementing cement; 3, casing; 31, casing reserved groove; 4, centralizer; 41, centralizer casing; 42, centralizer fin; 5, center pipe. DETAILED DESCRIPTION

[0023] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] Embodiment:

[0025] As Figures 1-4The application discloses a center pipe fixing structure for a middle-deep geothermal buried center pipe, which comprises, from outside to inside in a stratum 1, well cement 2, a casing 3, a centralizer 4 and a center pipe 5, wherein the casing 3 is deeply inserted into the stratum 1, the well cement 2 is filled between the casing 3 and the well wall of the stratum 1 to fix the casing 3, the well cement 2 fixes the casing 3 and the well wall to provide stable support for the casing 3 and to isolate corrosive substances in the stratum 1 to protect the casing 3 from corrosion, the center pipe 5 is fixedly connected to the casing 3 through the centralizer 4, the center pipe 5 is fixedly connected to the casing 3 through a plurality of centralizers 4, the vertical spacing of the centralizers 4 is 150m to 400m, the setting distance can be determined according to the well inclination of the geothermal well, the joint position of the center pipe 5 and other factors, the centralizers 4 are arranged at intervals along the extension direction of the center pipe 5, and the centralizers 4 can ensure that the center pipe 5 can always keep concentric and coaxial with the casing 3 under the action of a large circulating water pressure and does not tilt.

[0026] Further, as shown in Figure 3 and Figure 4 , the centralizer 4 comprises a centralizer casing 41 and a centralizer fin 42, the inner hole of the centralizer casing 41 is matched with the outer wall of the center pipe 5, and the center pipe 5 is fixedly connected in the centralizer casing 41; the centralizer fin 42 is in a strip shape and comprises a fixed end and a movable end, the fixed end is inclined upward by a predetermined angle and is uniformly distributed along the outer wall of the centralizer casing 41, the fixed end is welded to the centralizer casing 41, and the movable end is clamped and embedded on the casing 3.

[0027] The thickness of the centralizer casing 41 is 3mm to 10mm, and the height is 150mm to 300mm.

[0028] The movable end of the centralizer fin 42 is in an arc chamfer structure and has a thickness of 3mm to 5mm, each group of centralizer fins 42 of the centralizer 4 is 4 to 6, the direction is inclined upward, the predetermined angle is 40° to 45° with respect to the horizontal, the center pipe 5 can be smoothly lowered, and the centralizer 4 can ensure that the center pipe 5 is fixedly and firmly connected to the casing 3.

[0029] Further, as shown in Figure 2 , a casing reserved groove 31 is arranged on the casing 3 at the connection position of the centralizer fin 42, the movable end of the centralizer fin 42 is clamped and embedded in the casing reserved groove 31, and the size of the casing reserved groove 31 is matched with the movable end of the centralizer fin 42. The movable end of the centralizer fin 42 is in a chamfer arc structure, the centralizer fin 42 is clamped and embedded in the casing reserved groove 31 at an angle of 45° with respect to the horizontal, the centralizer fin 42 and the casing 3 can be effectively connected, and stress concentration at the connection position is avoided.

[0030] Further, the centralizer 4 is provided with multiple groups according to the field conditions, the central pipe 5 is connected and fixed with the casing 3 through the multiple groups of centralizers 4, the vertical spacing of each group of centralizers 4 is 150-400m, the setting distance can be determined according to the well inclination degree of the geothermal well, the joint position of the central pipe 5 and other factors, and the centralizer 4 can ensure that the central pipe 5 can always keep concentric and coaxial with the casing 3 under the action of the relatively large pressure of circulating water, and the inclination does not occur.

[0031] Further, the centralizer casing 41 is welded and connected with the outer wall of the central pipe 5.

[0032] The utility model can effectively solve the problem that the geothermal well central pipe 5 and the casing 3 cannot always keep concentric and coaxial, which leads to low heat extraction efficiency of the geothermal well and short service life of the central pipe 5. The central pipe centralizer 4 is arranged between the geothermal well central pipe 5 and the casing 3, which is beneficial to ensure that the central pipe 5 and the casing 3 always keep concentric and coaxial during the heat extraction process, the structure is safe and reliable, the construction is simple, the engineering cost and the construction period can be saved, and the purpose of achieving high heat extraction efficiency of the medium-deep geothermal well can be achieved.

[0033] In the case of no conflict, the person skilled in the art can combine the related technical features in the above examples according to the actual situation to achieve the corresponding technical effect, and the specific combinations are not described one by one.

[0034] The above is only a preferred embodiment of the utility model, and the utility model will not be limited to the embodiments shown in the text, but will conform to the widest range consistent with the principles and novel characteristics disclosed in the text. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the utility model still belong to the range of the technical scheme of the utility model.

Claims

1. A medium-depth geothermal buried central pipe fixing structure, characterized by: The application relates to a well cementing device, which comprises, from outside to inside, well cement (2), a casing (3), a centralizer (4) and a central pipe (5) arranged in a stratum (1), the casing (3) is deep into the stratum (1), the well cement (2) is filled between the casing (3) and the well wall of the stratum (1), the central pipe (5) is fixedly connected in the casing (3) through the centralizer (4), the centralizers (4) are arranged at intervals along the extension direction of the central pipe (5), and the central pipe (5) is ensured to keep concentric and coaxial with the casing (3) under the action of circulating water pressure; the centralizer (4) comprises a centralizer casing (41) and a centralizer fin (42), the inner hole of the centralizer casing (41) is matched with the outer wall of the central pipe (5), and the central pipe (5) is fixedly connected in the centralizer casing (41); the centralizer fin (42) is long-strip-shaped, comprises a fixed end and a movable end, the fixed end is inclined upward by a predetermined angle along the outer wall of the centralizer casing (41) in a circumferential direction, the fixed end is welded to the centralizer casing (41), and the movable end is clamped and connected on the casing (3); a casing reserved groove (31) is arranged on the casing (3) and connected with the centralizer fin (42), and the centralizer fin (42) is clamped in the casing reserved groove (31).

2. A medium-deep geothermal buried central pipe fixing structure according to claim 1, characterized in that: The thickness of the centralizer casing (41) is 3-10 mm, and the height is 150-300 mm.

3. A medium-deep geothermal buried central pipe fixing structure according to claim 1, characterized in that: The movable end of the centralizer fin (42) is arc chamfer structure, the thickness is 3-5 mm, and the centralizer fin (42) of each group of centralizers (4) is 4-6.

4. A medium-deep geothermal buried central pipe fixing structure according to claim 1, characterized in that: The predetermined angle of the centralizer fin (42) inclined upward is 40-45 degrees with the horizontal angle.

5. A medium-deep geothermal buried central pipe fixing structure according to claim 1, characterized in that: The size of the casing reserved groove (31) is matched with the movable end of the centralizer fin (42).

6. A medium-deep geothermal buried central pipe fixing structure according to claim 1, characterized in that: The centralizers (4) are arranged in multiple groups according to the field conditions, and the vertical spacing of the centralizers (4) is 150-400 m.

7. A medium-deep geothermal buried central pipe fixing structure according to any one of claims 1-6, characterized in that: The centralizer casing (41) is welded to the outer wall of the central pipe (5).

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