Sandstone layered geothermal exploitation and irrigation well and geothermal exploitation and irrigation system

Abstract

The utility model provides a sandstone stratified geothermal exploitation and irrigation well and a geothermal exploitation and irrigation system, and relates to the technical field of geothermal wells, the sandstone stratified geothermal exploitation and irrigation well comprises a first well opening section and a second well opening section, the first well opening section and the second well opening section are respectively provided with a first well opening sleeve and a second well opening sleeve, the second well opening sleeve penetrates through at least two sandstone water layers, and through holes are formed in the pipe walls, located on the sandstone water layers, of the second well opening sleeve; the central pipe comprises a first pipe section and a second pipe section which are sequentially arranged from top to bottom, the outer diameter of the second pipe section is smaller than that of the first pipe section, the first pipe section is connected with the second pipe section through a reducing flange, the reducing flange is located between the two sandstone water layers, and the periphery of the reducing flange is connected with the two-section casing pipe through a bearing part; the upper part of the first pipe section is positioned in the first open sleeve and is connected with a water collecting pump, the lower part of the first pipe section is provided with a first water passing part, and the second pipe section is provided with a second water passing part; the problems that in the prior art, due to the fact that a water layer is sealed and separated in the mode that a packer is put down, a central pipe is difficult to take out, and the maintenance cost is high are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of geothermal wells, and more specifically, relates to a sandstone layered geothermal production and irrigation well and a geothermal production and irrigation system. Background Art

[0002] In the process of developing hydrothermal geothermal resources, it is necessary to recharge the high-temperature groundwater after extraction through reinjection wells into the underground reservoir after heat exchange on the ground. The current geothermal development plan mainly deploys water extraction wells and reinjection wells separately to achieve the development and utilization of geothermal energy. This general development model of well heat reservoirs does not fully utilize the physical properties of heat reservoirs, resulting in ineffective utilization of geothermal resources. Secondly, in order to isolate the water layer, the method of inserting a packer was usually used in the past. In the later stage, it was easy to have problems with the difficulty of removing the pipe string, the maintenance cost was high, and it was difficult to selectively develop and utilize the heat reservoir according to needs. Utility Model Content

[0003] The purpose of the utility model is to provide a sandstone stratified geothermal production and injection well and a geothermal production and injection system to address the deficiencies in the prior art, so as to solve the problem that the prior art uses a method of lowering a packer to isolate the water layer, resulting in difficulty in removing the central pipe and high maintenance costs.

[0004] In order to achieve the above-mentioned purpose, the utility model provides a sandstone layered geothermal well injection, comprising:

[0005] A first well section and a second well section, wherein the first well section and the second well section are respectively provided with a first casing and a second casing, and the first casing is connected to the second casing, the second casing passes through at least two sandstone water layers, and a through hole is opened on the pipe wall of the second casing in the sandstone water layer;

[0006] A center pipe, the center pipe is passed through the single-open casing and the double-open casing, the center pipe comprises a first pipe section and a second pipe section which are sequentially arranged from top to bottom, the outer diameter of the second pipe section is smaller than the outer diameter of the first pipe section, and the first pipe section is connected to the second pipe section via a reducing flange, the reducing flange is located between the two sandstone water layers, and the outer periphery of the reducing flange is connected to the double-open casing via a bearing member, the upper portion of the first pipe section is located in the single-open casing and is connected to a water production pump, the lower portion of the first pipe section is provided with a first water-passing component, and the second pipe section is provided with a second water-passing component.

[0007] Optionally, the first water passing component and the second water passing component are respectively a first water eye casing and a second water eye casing, and the first water eye casing and the second water eye casing are respectively connected to the first pipe section and the second pipe section through threads.

[0008] Optionally, the first water eye casing and the second water eye casing are electrically controlled water eye casings or pneumatically controlled water eye casings.

[0009] Optionally, the bearing member is an annular short section.

[0010] Optionally, the double-opening casing passes through two sandstone water layers, and the two sandstone water layers are, from top to bottom, a first sandstone water layer and a second sandstone water layer.

[0011] Optionally, a water stopper is provided between the second pipe section and the double-open casing, and at least one such water stopper is provided on the upper part of the second sandstone water layer.

[0012] Optionally, at least one water stopper is provided at the lower part of the second sandstone water layer below the second water hole casing.

[0013] Optionally, the water stopper is expansion rubber.

[0014] Optionally, a sealing member is provided on the upper side of the carrier.

[0015] The utility model also includes a geothermal extraction and irrigation system, comprising the above-mentioned geothermal extraction and irrigation well.

[0016] The utility model provides a sandstone stratified geothermal production and injection well and a geothermal production and injection system, which have the following beneficial effects: the sandstone stratified geothermal production and injection well has an open casing and a double open casing that are connected to each other, the through holes on the double open casing can be used for geothermal water production and reinjection in the sandstone water layer, the interior of the central pipe is used for water production, and the peripheral annulus of the central pipe is used for reinjection, and the water production and reinjection functions of geothermal water can be realized in a single well; the central pipe adopts a first pipe section and a second pipe section to be connected through a reducer flange, a support is arranged between the reducer flange and the double open casing, the reducer flange and the central pipe are supported, and the isolation between the two sandstone water layers is realized by the central pipe sealing method, the central pipe is convenient to be raised and lowered in the later stage, and is easy to maintain, thereby reducing the maintenance cost.

[0017] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present invention.

[0019] Figure 1 A structural schematic diagram of a sandstone layered geothermal well injection and water production state according to an embodiment of the utility model is shown.

[0020] Figure 2 A structural schematic diagram of a sandstone layered geothermal production and injection well water production and re-injection state according to an embodiment of the utility model is shown.

[0021] Description of reference numerals:

[0022] 1. One-open casing; 2. Flange; 3. Pipeline pump; 4. Two-open casing; 5. Center pipe; 6. First water eye sliding sleeve; 7. Reducer flange; 8. Seal; 9. Bearing member; 10. Water stop; 11. First sandstone water layer; 12. Second sandstone water layer. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0024] The utility model provides a sandstone layered geothermal well, comprising:

[0025] A first well section and a second well section are provided with a first casing and a second casing respectively, and the first casing is connected with the second casing, the second casing passes through at least two sandstone water layers, and a through hole is provided on the pipe wall of the second casing in the sandstone water layer;

[0026] The central pipe is passed through an open casing and a double-open casing, and comprises a first pipe section and a second pipe section which are sequentially arranged from top to bottom. The outer diameter of the second pipe section is smaller than the outer diameter of the first pipe section, and the first pipe section is connected to the second pipe section through a reducing flange, the reducing flange is located between two sandstone water layers, and the outer periphery of the reducing flange is connected to the double-open casing through a bearing member, the upper part of the first pipe section is located in the open casing and is connected to a water production pump, the lower part of the first pipe section is provided with a first water passing component, and the second pipe section is provided with a second water passing component.

[0027] Specifically, in order to solve the problem that the water layer is isolated by inserting a packer in the prior art, which makes it difficult to remove the central pipe and has a high maintenance cost; the sandstone stratified geothermal production and injection well provided by the utility model has an open casing and a double-open casing that are connected to each other, the through holes on the double-open casing can be used for geothermal water production and reinjection in the sandstone water layer, the interior of the central pipe is used for water production, and the peripheral annulus of the central pipe is used for reinjection, which can realize the geothermal water production and reinjection functions in a single well; the central pipe adopts a first pipe section and a second pipe section to be connected by a reducer flange, and a support is provided between the reducer flange and the double-open casing to support the reducer flange and the central pipe, and the isolation between the two sandstone water layers is achieved by the central pipe seating method, and the central pipe is convenient to be raised and lowered in the later stage, which is convenient for maintenance and reduces the maintenance cost.

[0028] Optionally, the first water passing component and the second water passing component are respectively the first water eye casing and the second water eye casing, and the first water eye casing and the second water eye casing are respectively connected to the first pipe section and the second pipe section through threads.

[0029] Specifically, the first pipe section and the second pipe section respectively use the first water passing component and the second water passing component to pass water, so that the geothermal water can enter the central pipe and be collected by the water collection pump. The first water eye casing and the second water eye casing are coaxially connected to the central pipe in a threaded connection manner.

[0030] Optionally, the first water eye casing and the second water eye casing are electrically controlled water eye casings or pneumatically controlled water eye casings.

[0031] Specifically, the first water eye casing and the second water eye casing can both adopt electrically controlled water eye casings or pneumatically controlled water eye casings, and their opening and closing are controlled by electrically or pneumatically controlled methods, thereby realizing the switching of the state of passing water or not passing water, and they can be opened and closed by lowering cables or air pipes.

[0032] Furthermore, due to the arrangement of the first water hole casing and the second water hole casing, it is possible to control water extraction from any one of the two sandstone water layers or from both of them at the same time, and one of them can be opened and the other closed. While water is being extracted from one sandstone water layer, water is reinjected into the other sandstone water layer through the annulus outside the central pipe. The extraction and reinjection of geothermal water can be achieved in a single well, and can be controlled simply and flexibly.

[0033] Optionally, the bearing member is an annular short section.

[0034] Specifically, the bearing member is an annular short section, and the annular short section is fixedly connected to the inner wall of the double-open casing.

[0035] Optionally, the double-opening casing passes through two sandstone water layers, and the two sandstone water layers are, from top to bottom, a first sandstone water layer and a second sandstone water layer.

[0036] Specifically, the first sandstone water layer and the second sandstone water layer are arranged between each other, and the reducer flange connecting the first pipe segment and the second pipe segment and the bearing member are located between the first sandstone water layer and the second sandstone water layer.

[0037] Optionally, a water stopper is provided between the second pipe section and the second open casing, and at least one water stopper is provided on the upper part of the second sandstone water layer.

[0038] Specifically, the water stopper is used for the water-stopping connection between the second open casing and the central pipe to seal the annulus outside the central pipe. At least one water stopper is arranged on the upper part of the second sandstone water layer to seal the first sandstone water layer so that the first sandstone water layer can only be connected with the first pipe section through the setting of the first water hole casing.

[0039] Optionally, at least one water stopper is provided in the lower part of the second sandstone water layer below the second water hole casing.

[0040] Specifically, at least one water stopper is also provided at the lower part of the second sandstone water layer, and the water stopper is located below the second water hole casing, so that the second sandstone water layer can only be connected with the second pipe section through the second water hole casing.

[0041] Optionally, the water stop is expansion rubber.

[0042] Specifically, the water stopper may be made of expansion rubber and is used to seal the annulus between the central pipe and the secondary casing.

[0043] Optionally, a sealing element is provided on the upper side of the carrier.

[0044] Specifically, the sealing member is used to seal between the reducing flange and the double-open sleeve on the upper side of the bearing member, and the sealing member can be a rubber ring.

[0045] The utility model also includes a geothermal extraction and irrigation system, comprising the above-mentioned geothermal extraction and irrigation well.

[0046] Specifically, at least one of the above-mentioned geothermal production and injection wells is used in the geothermal production and injection system. The above-mentioned geothermal production and injection well is convenient for flexible control to produce water from the first sandstone water layer and / or the second sandstone water layer through the arrangement of the water stopper, the first water hole casing and the second water hole casing, and can also realize geothermal water production and injection of a single well by controlling the opening and closing of the first water hole casing and the second water hole casing as well as the water production and reinjection mode, adopting the operation mode of water production and reinjection, so as to adopt the operation mode of water production and reinjection, and can selectively and efficiently develop and utilize the heat reservoir as needed.

[0047] Embodiment 1

[0048] like Figure 1 and Figure 2 As shown, the utility model provides a sandstone layered geothermal well filling method, comprising:

[0049] A first well section and a second well section, wherein a first casing 1 and a second casing 4 are respectively arranged in the first well section and the second well section, and the first casing 1 is connected to the second casing 4, the second casing 4 passes through at least two sandstone water layers, and a through hole is opened on the pipe wall of the second casing 4 in the sandstone water layer;

[0050] The central pipe 5 is passed through the single-open casing 1 and the double-open casing 4. The central pipe 5 includes a first pipe section and a second pipe section which are sequentially arranged from top to bottom. The outer diameter of the second pipe section is smaller than the outer diameter of the first pipe section, and the first pipe section is connected to the second pipe section through a reducing flange 7. The reducing flange 7 is located between two sandstone water layers, and the outer periphery of the reducing flange 7 is connected to the double-open casing 4 through a bearing member 9. The upper part of the first pipe section is located in the single-open casing 1 and is connected to a water production pump. The lower part of the first pipe section is provided with a first water-passing component, and the second pipe section is provided with a second water-passing component.

[0051] In this embodiment, the sandstone stratified geothermal well is a vertical well or a directional well, and the first well section is a vertical well section, which serves as a pump chamber section; the second well casing 4 is connected to the first well casing 1 through a hanger, and after the second well casing 4 is lowered, cement is cemented, and the target layer section is perforated to form a through hole.

[0052] In this embodiment, the water production pump is a pipeline pump 3, both ends of which are connected to the first pipe section through flanges 2. Geothermal water can be output to the ground through the pipeline pump 3. The outer casing of the pipeline pump 3 has the same tensile strength as the central pipe 5, and the length of the first pipe section is less than the length of an open casing 1.

[0053] Optionally, the first water passing component and the second water passing component are respectively the first water eye casing and the second water eye casing, and the first water eye casing and the second water eye casing are respectively connected to the first pipe section and the second pipe section through threads.

[0054] Optionally, the first water eye casing and the second water eye casing are electrically controlled water eye casings or pneumatically controlled water eye casings.

[0055] Optionally, the bearing member 9 is an annular short section.

[0056] In this embodiment, the bearing member 9 is a metal member connected to the double-open sleeve 4 .

[0057] Optionally, the double-opening casing 4 passes through two sandstone water layers, and the two sandstone water layers are a first sandstone water layer 11 and a second sandstone water layer 12 from top to bottom.

[0058] Optionally, a water stopper 10 is provided between the second pipe section and the second open casing 4 , and at least one water stopper 10 is provided on the upper part of the second sandstone water layer 12 .

[0059] Optionally, at least one water stopper 10 is provided at the lower part of the second sandstone water layer 12 below the second water hole casing.

[0060] Optionally, the water stopper 10 is expansion rubber.

[0061] Optionally, a seal 8 is provided on the upper side of the carrier 9 .

[0062] In this embodiment, the sealing member 8 is a rubber ring. When the central tube 5 is lowered, the reducing flange 7 is seated on the bearing member 9 and the sealing member 8 to seal the space above and below the reducing flange 7 .

[0063] like Figure 1 As shown, by opening the first water eye sliding sleeve 6 and the second water eye sliding sleeve, the geothermal water of the two sandstone water layers can be exploited simultaneously; by opening either the first water eye sliding sleeve 6 or the second water eye sliding sleeve, the geothermal water of the two sandstone water layers can be exploited separately; Figure 2 As shown, the second water eye sliding sleeve is opened and the first water eye sliding sleeve 6 is closed, water can be produced from the second sandstone water layer 12, and the tail water after heat exchange is re-injected into the first sandstone water layer 11 through the annulus, realizing single-well production and injection.

[0064] The sandstone stratified geothermal production and injection well achieves the isolation of two sandstone water layers by sealing the central pipe 5. The central pipe 5 is easy to raise and lower later. The use of the pipeline pump 3 reduces the construction procedures, and the well completion operation can be completed in one operation. The sandstone stratified geothermal production and injection well adopts the central pipe 5 to connect the pipeline pump 3, which reduces the construction procedures and the well completion operation can be completed in one operation. The sandstone stratified geothermal production and injection well realizes the combined production, separate production and single-well production and injection of two sandstone water layers through the combined use of the water eye sliding sleeve and the water stop 10.

[0065] Embodiment 2

[0066] The utility model also includes a geothermal extraction and irrigation system, comprising the above-mentioned geothermal extraction and irrigation well.

[0067] In this embodiment, a plurality of the above-mentioned geothermal production and injection wells are used in the geothermal production and injection system. The above-mentioned geothermal production and injection wells are conveniently and flexibly controlled to produce water from the first sandstone water layer 11 and / or the second sandstone water layer 12 by means of the arrangement of the water stopper 10, the first water hole casing and the second water hole casing. In addition, the opening and closing of the first water hole casing and the second water hole casing as well as the water production and reinjection mode can be controlled, and the operation mode of producing and reinjecting at the same time can be adopted to realize geothermal water production and injection of a single well, so that the heat reservoir can be selectively and efficiently developed and utilized as needed.

[0068] The various embodiments of the utility model have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A sandstone layered geothermal well, characterized in that: include: A first well section and a second well section, wherein the first well section and the second well section are respectively provided with a first casing and a second casing, and the first casing is connected to the second casing, the second casing passes through at least two sandstone water layers, and a through hole is opened on the pipe wall of the second casing in the sandstone water layer; A center pipe, the center pipe is passed through the single-open casing and the double-open casing, the center pipe comprises a first pipe section and a second pipe section which are sequentially arranged from top to bottom, the outer diameter of the second pipe section is smaller than the outer diameter of the first pipe section, and the first pipe section is connected to the second pipe section via a reducing flange, the reducing flange is located between the two sandstone water layers, and the outer periphery of the reducing flange is connected to the double-open casing via a bearing member, the upper portion of the first pipe section is located in the single-open casing and is connected to a water production pump, the lower portion of the first pipe section is provided with a first water-passing component, and the second pipe section is provided with a second water-passing component.

2. The sandstone layered geothermal well filling method according to claim 1 is characterized in that: The first water-passing component and the second water-passing component are respectively a first water-eye casing and a second water-eye casing, and the first water-eye casing and the second water-eye casing are respectively connected to the first pipe section and the second pipe section through threads.

3. The sandstone layered geothermal well filling method according to claim 2 is characterized in that: The first water eye casing and the second water eye casing are electrically controlled water eye casings or pneumatically controlled water eye casings.

4. The sandstone layered geothermal well filling method according to claim 1 is characterized in that: The bearing member is an annular short section.

5. The sandstone layered geothermal well filling method according to claim 2 is characterized in that: The double-open casing passes through the two sandstone water layers, and the two sandstone water layers are the first sandstone water layer and the second sandstone water layer from top to bottom.

6. The sandstone layered geothermal well filling method according to claim 5 is characterized in that: A water stopper is arranged between the second pipe section and the double-open casing, and at least one water stopper is arranged on the upper part of the second sandstone water layer.

7. The sandstone layered geothermal well filling method according to claim 6 is characterized in that: At least one water stopper is arranged at the lower part of the second sandstone water layer below the second water hole casing.

8. The sandstone layered geothermal well filling method according to claim 7 is characterized in that: The water stopper is expansion rubber.

9. The sandstone layered geothermal well filling method according to claim 1, characterized in that: A sealing member is arranged on the upper side of the carrier.

10. A geothermal extraction and irrigation system, characterized in that: It comprises a geothermal production and injection well according to any one of claims 1-9.

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