Geothermal exploitation and irrigation well and geothermal exploitation and irrigation system

Abstract

The utility model provides a terrestrial heat exploitation and irrigation well and a terrestrial heat exploitation and irrigation system, and relates to the technical field of terrestrial heat wells, the terrestrial heat exploitation and irrigation well comprises a first well opening section and a second well opening section, a first well opening casing pipe and a second well opening casing pipe are respectively arranged in the first well opening section and the second well opening section, the first well opening casing pipe is connected with the second well opening casing pipe, and a first through hole is formed in the pipe wall of the second well opening casing pipe in a water exploitation layer. A second through hole is formed in the pipe wall, located on the recharge layer, of the second-section casing pipe; the central pipe is arranged in the first-opening casing pipe and the second-opening casing pipe in a penetrating mode, a packer and a water stop device are arranged between the central pipe and the second-opening casing pipe, the packer is arranged between the recharge layer and the water collection layer, and the water stop device is arranged below the packer in a spaced mode; the problems that in the prior art, a water production well and a recharge well are adopted for completing water production and recharge of geothermal water respectively, the operation process and later maintenance are relatively complex, and deployment is inconvenient are solved.

Description

Technical Field

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

[0002] In the process of developing hydrothermal geothermal resources, it is necessary to exchange heat on the ground with the high-temperature groundwater after mining, and then re-inject it into the underground reservoir through the re-injection well. The current geothermal development plan mainly deploys water production wells and re-injection wells separately to realize the development and utilization of geothermal energy. However, due to the differences in the physical properties and temperature of the target thermal reservoir, the general development model causes the strata with better physical properties in the upper part of the thermal reservoir to affect the water production temperature, so that the high-temperature strata in the lower part of the thermal reservoir cannot be effectively developed, and the better physical properties of the upper thermal reservoir are not effectively utilized. Secondly, in the process of geothermal development, due to the space limitations of the area of ​​the community and the horizontal direction of the adjacent wells, the conventional mining and injection well deployment methods will result in the situation where the wells cannot be deployed, which seriously restricts the formulation of geothermal development plans. Utility Model Content

[0003] The purpose of the utility model is to provide a geothermal extraction and injection well and a geothermal extraction and injection system in view of the deficiencies in the prior art, so as to solve the problems that the prior art uses extraction wells and injection wells to respectively complete the extraction and injection of geothermal water, and the operation process and subsequent maintenance are relatively complicated and the deployment is inconvenient.

[0004] In order to achieve the above-mentioned purpose, the utility model provides a geothermal well, 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, a first through hole is opened on the pipe wall of the second casing in the water production layer, and a second through hole is opened on the pipe wall of the second casing in the recharging layer;

[0006] A center pipe, wherein the center pipe is passed through the first open casing and the second open casing, a packer and a water stopper are arranged between the center pipe and the second open casing, the packer is arranged between the reinjection layer and the water production layer, and the water stopper is arranged below the packer.

[0007] Optionally, the diameter of the first open casing is greater than the diameter of the second open casing, and the first open casing is connected to the second open casing via a tail pipe suspension structure.

[0008] Optionally, the central pipe includes a first pipe and a second pipe, the diameter of the first pipe is larger than that of the second pipe, the lower end of the first pipe is located above the lower end of the open casing, and the interior of the first pipe is used to install a submersible pump.

[0009] Optionally, the second pipe is connected to the first pipe via a reducing flange.

[0010] Optionally, the submersible pump is arranged in a first pipe and a pump pipe of the submersible pump is connected to the first pipe via an elastic stabilizer.

[0011] Optionally, the packer and the water stopper are arranged close to the recharge layer and the water production layer respectively.

[0012] Optionally, a telescopic compensator is provided above the packer, and the telescopic compensator is connected to the central pipe.

[0013] Optionally, the lower end of the central pipe is located in the water production layer.

[0014] Optionally, the packer is a pressure seal, a ball seal or an electric control seal, and the water stopper is expansion rubber.

[0015] The present invention also provides a geothermal extraction and irrigation system, comprising the above-mentioned geothermal extraction and irrigation well.

[0016] The utility model provides a geothermal production and injection well and a geothermal production and injection system, which has the beneficial effects that: the geothermal production and injection well has an open casing and a double open casing connected to each other, the first through hole and the second through hole on the double open casing are respectively used for geothermal water production in the water production layer and geothermal water reinjection in the reinjection layer, the interior of the central pipe is used for water production, and the peripheral annulus of the central pipe is used for reinjection, the arrangement of the packer can seal the reinjection water above the water production layer, and the water stopper is arranged at intervals below the packer, which can reduce the cooling effect of the low temperature of the reinjection water on the lower water production layer, thereby improving the utilization rate and utilization effect of geothermal energy; the geothermal production and injection well can not only realize the production and reinjection of geothermal water on a single well, simplify the operation process and later maintenance, but also improve the utilization of geothermal energy and fully tap the development potential of heat storage.

[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 schematic structural diagram of a geothermal well according to an embodiment of the utility model is shown.

[0020] Description of reference numerals:

[0021] 1. First pipe; 2. First open casing; 3. Variable diameter flange; 4. Second open casing; 5. Second pipe; 6. Recharge layer; 7. Packer; 8. Water stop; 9. Water production layer; 10. Pump pipe; 11. Elastic centralizer; 12. Submersible pump. DETAILED DESCRIPTION

[0022] 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.

[0023] The utility model provides a geothermal well, comprising:

[0024] A first well section and a second well section, wherein a first casing and a second casing are respectively arranged in the first well section and the second well section, and the first casing is connected to the second casing, a first through hole is opened on the pipe wall of the second casing in the water production layer, and a second through hole is opened on the pipe wall of the second casing in the recharging layer;

[0025] The center pipe is passed through the first-open casing and the second-open casing. A packer and a water stopper are arranged between the center pipe and the second-open casing. The packer is arranged between the reinjection layer and the water production layer, and the water stopper is arranged below the packer.

[0026] Specifically, in order to solve the problem that the prior art uses water production wells and reinjection wells to respectively complete geothermal water production and reinjection, the operation process and subsequent maintenance are relatively complicated, and the deployment is inconvenient; the geothermal production and injection well provided by the utility model has an open casing and a two-open casing that are connected to each other, the first through hole and the second through hole on the two-open casing are respectively used for geothermal water production in the water production layer and geothermal water reinjection in the reinjection layer, the interior of the central tube is used for water production, and the peripheral annulus of the central tube is used for reinjection, the setting of the packer can seal the reinjection water above the water production layer, and the water stopper is arranged at intervals below the packer, which can reduce the cooling effect of the low temperature of the reinjection water on the lower water production layer, thereby improving the utilization rate and utilization effect of geothermal energy; the geothermal production and injection well can not only realize the production and reinjection of geothermal water on a single well, simplify the operation process and subsequent maintenance, but also improve the utilization of geothermal energy and fully tap the development potential of heat storage.

[0027] Furthermore, the geothermal well is a vertical well or a directional well, wherein one of the well sections is a vertical well section.

[0028] Optionally, the diameter of the first open casing is greater than the diameter of the second open casing, and the first open casing is connected to the second open casing via a tail pipe suspension structure.

[0029] Specifically, the first open casing is connected to the second open casing by a tail pipe suspension method through a hanger.

[0030] Furthermore, it may also include a three-open casing, wherein the first-open casing, the second-open casing and the third-open casing are connected in sequence.

[0031] Optionally, the central tube includes a first tube and a second tube, the diameter of the first tube is larger than that of the second tube, the lower end of the first tube is located above the lower end of the open casing, and the interior of the first tube is used to install a submersible pump.

[0032] Specifically, the central pipe adopts a reducer, and the diameter of the first pipe is larger than that of the second pipe, which is used to accommodate a submersible pump. The depth of the pump is less than the depth of an open casing, and an annulus is formed between the first pipe and the open casing so that the reinjection water flows downward into the reinjection channel between the second pipe and the two open casings.

[0033] Optionally, the second pipe is connected to the first pipe via a reducing flange.

[0034] Specifically, the reducing flange is located above the double-open casing, connecting the second pipe to the bottom of the first pipe.

[0035] Optionally, the submersible pump is arranged in the first pipe and the pump pipe of the submersible pump is connected to the first pipe through an elastic stabilizer.

[0036] Specifically, the submersible pump is arranged in the first pipe, connected to the wellhead through a pump pipe, and geothermal water is transported upward through the pump pipe. The elastic centralizer is arranged to ensure the centering degree of the submersible pump in the central pipe.

[0037] In one example, the pump tube is made of steel.

[0038] Optionally, the packer and the water stopper are respectively arranged close to the reinjection layer and the water production layer.

[0039] Specifically, the installation position of the packer and the water stopper, the second casing is a solid pipe, the packer is set close to the reinjection layer, and the water stopper is set close to the water production layer, to ensure that the interval between the two is as large as possible, so as to reduce the impact of the reinjected low-temperature water on the lower production layer and increase the heat transfer distance.

[0040] Optionally, a telescopic compensator is provided above the packer, and the telescopic compensator is connected to the central pipe.

[0041] Specifically, the telescopic compensator is connected to the center tube through threads, and has a certain axial movement space when used to lift the center tube.

[0042] Optionally, the lower end of the central tube is located in the water production layer.

[0043] Specifically, the lower end of the central pipe extends into the water-collecting layer, that is, the lowering depth of the second pipe is lower than the upper end of the water-collecting layer, thereby ensuring water collection efficiency.

[0044] Optionally, the packer is a pressure seal, a ball seal or an electric control seal, and the water stopper is an expansion rubber.

[0045] Specifically, the packer can use a pressure seat seal, a ball seat seal or an electric control seat seal to achieve the isolation of the annulus between the center pipe and the secondary casing. A rubber water stopper has little effect on the raising and lowering of the center pipe.

[0046] In one example, the center tube and the reducer flange are both made of steel.

[0047] In one example, the diameter of the second tubular is smaller than the diameter of the last secondary casing of the well completion.

[0048] Taking an example as an example, during the construction of geothermal wells provided by the utility model, a Ф444.5mm drill bit is used to drill to a well depth of 350m, and a Ф339.7mm first-opening casing is lowered to 350m to meet the requirements of sealing the loose surface strata and lowering the water pump. The cement returns to the ground, and the cement plug in the casing string is 10m. After the first-opening cementing is completed, a 241.3mm drill bit is used to sweep the plug and clear the well, and then the second opening operation is carried out; the second opening is drilled to the completed well depth with a Ф241.3mm drill bit, and well logging operations are carried out to determine the main water production layer section (S2-S3), the recharging layer section (S4-S5) and the separation position of the two layers; the second opening casing is connected by a tail pipe suspension method, and the overlapping section 50 m, casing diameter Φ177.8mm, cement is used to seal the annulus outside the pipe, and the selected layer is perforated and completed; then, the central pipe is lowered, from top to bottom, there are 244.5mm first pipe, reducer flange, 114.3mm second pipe, packer, 114.3mm second pipe, water stopper, and second pipe; in one example, the length of the first pipe is S1-10m, and the depth of the second pipe is S4+20m; the position of the packer is between S3-S4, the position of the water stopper is 10m below the packer, and there are two groups of water stops, one group of three, and the spacing between the two groups of packers is 5m; then the submersible pump is lowered, the upper part of the submersible pump is connected by a pump pipe, and the bottom depth of the submersible pump is 100m. When in use, turn on the submersible pump, and the geothermal water is produced through the water-producing layer through the center pipe. After heat exchange on the ground, it is recharged to the recharge layer through the annulus.

[0049] The present invention also provides a geothermal extraction and irrigation system, comprising the above-mentioned geothermal extraction and irrigation well.

[0050] Specifically, the geothermal extraction and injection system is different from the traditional method of using extraction wells and injection wells to complete the extraction and injection of geothermal water respectively. Instead, it uses the above-mentioned geothermal extraction and injection wells, which can not only realize the extraction and injection of geothermal water in a single well, simplify the operation process and subsequent maintenance, but also improve the utilization of geothermal energy and fully tap the development potential of heat storage.

[0051] Embodiment 1

[0052] like Figure 1 As shown, the utility model provides a geothermal well, comprising:

[0053] A first well section and a second well section, wherein a first casing 2 and a second casing 4 are respectively arranged in the first well section and the second well section, and the first casing 2 is connected to the second casing 4, a first through hole is opened on the pipe wall of the second casing 4 in the water production layer 9, and a second through hole is opened on the pipe wall of the second casing 4 in the recharging layer 6;

[0054] The center pipe is passed through the first open casing 2 and the second open casing 4. A packer 7 and a water stopper 8 are arranged between the center pipe and the second open casing 4. The packer 7 is arranged between the reinjection layer 6 and the water production layer 9. The water stopper 8 is arranged below the packer 7 at intervals.

[0055] Specifically, in order to solve the problem that the prior art uses water production wells and reinjection wells to respectively complete geothermal water production and reinjection, the operation process and subsequent maintenance are relatively complicated, and the deployment is inconvenient; the geothermal production and injection well provided by the utility model has an open casing 2 and a second open casing 4 that are connected to each other, the first through hole and the second through hole on the second open casing 4 are respectively used for geothermal water production in the water production layer 9 and geothermal water reinjection in the reinjection layer 6, the interior of the central tube is used for water production, and the peripheral annulus of the central tube is used for reinjection, the setting of the packer 7 can isolate the reinjection water above the water production layer 9, and the water stopper 8 is arranged at intervals below the packer 7, which can reduce the cooling effect of the low temperature of the reinjection water on the lower water production layer 9, thereby improving the utilization rate and utilization effect of geothermal energy; the geothermal production and injection well can not only realize the production and reinjection of geothermal water on a single well, simplify the operation process and subsequent maintenance, but also improve the utilization of geothermal energy and fully tap the development potential of heat storage.

[0056] Furthermore, the geothermal well is a vertical well or a directional well, wherein one of the well sections is a vertical well section.

[0057] In this embodiment, the diameter of the first open casing 2 is greater than the diameter of the second open casing 4, and the first open casing 2 is connected to the second open casing 4 through a tail pipe suspension structure.

[0058] Specifically, the first open casing 2 is connected to the second open casing 4 by a tail pipe suspension method through a hanger.

[0059] Furthermore, a three-open casing may be included, wherein the first-open casing 2, the second-open casing 4 and the third-open casing are connected in sequence.

[0060] In this embodiment, the central pipe includes a first pipe 1 and a second pipe 5. The diameter of the first pipe 1 is larger than that of the second pipe 5. The lower end of the first pipe 1 is above the lower end of an open casing 2. The interior of the first pipe 1 is used to install a submersible pump 12.

[0061] Specifically, the central pipe adopts a reducer, and the diameter of the first pipe 1 is larger than that of the second pipe 5, which is used to accommodate a submersible pump 12, and its lowering depth is less than that of an open casing 2. An annulus is formed between the first pipe 1 and the open casing 2, so that the reinjection water flows downward into the reinjection channel between the second pipe 5 and the second open casing 4.

[0062] In this embodiment, the second pipe 5 is connected to the first pipe 1 via the reducing flange 3 .

[0063] Specifically, the reducing flange 3 is located above the double-open sleeve 4 , and connects the second pipe 5 to the bottom of the first pipe 1 .

[0064] In this embodiment, the submersible pump 12 is disposed in the first pipe 1 and the pump pipe 10 of the submersible pump 12 is connected to the first pipe 1 via an elastic centralizer 11 .

[0065] Specifically, the submersible pump 12 is disposed in the first pipe 1, connected to the wellhead through the pump pipe 10, and geothermal water is transported upward through the pump pipe 10. The elastic centralizer 11 is provided to ensure the centering degree of the submersible pump 12 in the central pipe.

[0066] In this embodiment, the pump tube 10 is made of steel.

[0067] In this embodiment, the packer 7 and the water stopper 8 are respectively arranged close to the recharging layer 6 and the water production layer 9.

[0068] Specifically, the installation positions of the packer 7 and the water stopper 8 are such that the second casing is a solid pipe, the packer 7 is arranged close to the reinjection layer 6, and the water stopper 8 is arranged close to the water production layer 9, to ensure that the interval between the two is as large as possible, so as to reduce the impact of the reinjected low-temperature water on the lower production layer and increase the heat transfer distance.

[0069] In this embodiment, a telescopic compensator is arranged above the packer 7, and the telescopic compensator is connected to the central pipe.

[0070] Specifically, the telescopic compensator is connected to the center tube through threads, and has a certain axial movement space when used to lift the center tube.

[0071] In this embodiment, the lower end of the central tube is located in the water production layer 9 .

[0072] Specifically, the lower end of the central tube extends into the water extraction layer 9, that is, the lowering depth of the second tube 5 is lower than the upper end of the water extraction layer 9, thereby ensuring water extraction efficiency.

[0073] In this embodiment, the packer 7 is a pressure seal, a ball seal or an electric control seal, and the water stopper 8 is an expansion rubber.

[0074] Specifically, the packer 7 can use a pressure seal, a ball seal or an electric control seal to seal the annulus between the central pipe and the secondary casing. The rubber water stopper 8 has little effect on the raising and lowering of the central pipe 5.

[0075] In this embodiment, the center tube and the reducing flange 3 are both made of steel.

[0076] In this embodiment, the diameter of the second pipe 5 is smaller than the diameter of the last secondary casing in the well completion.

[0077] In summary, during the construction of geothermal wells provided by the utility model, a Ф444.5mm drill bit is used to drill to a well depth of 350m, and a Ф339.7mm first-opening casing is lowered from 2 to 350m to meet the requirements of sealing the loose surface formation and lowering the water pump, and the cement is returned to the ground. The cement plug in the casing string is 10m. After the first-opening cementing is completed, a 241.3mm drill bit is used to sweep the plug and clear the well, and then the second opening operation is carried out; the second opening is drilled to the completed well depth with a Ф241.3mm drill bit, and well logging operations are carried out to determine the main water production layer section (S2-S3), the recharging layer 6 sections (S4-S5) and the separation position of the two layers; the second opening casing 4 is connected by tail pipe suspension, the overlapping section is 50m, and the casing diameter is Φ177.8 mm, cement is used to seal the annulus outside the pipe, and the selected layer is perforated and completed; then, the central pipe is lowered, from top to bottom, there are 244.5mm first pipe 1, reducer flange 3, 114.3mm second pipe 5, packer 7, 114.3mm second pipe 5, water stopper 8, second pipe 5; in this embodiment, the length of the first pipe 1 is S1-10m, and the depth of the second pipe 5 is S4+20m; the position of the packer 7 is between S3-S4, the position of the water stopper 8 is 10m below the packer 7, and the water stopper 8 is two groups, one group has three, and the distance between the two groups of packers 7 is 5m; then the submersible pump 12 is lowered, the upper part of the submersible pump 12 is connected by the pump pipe 10, and the bottom depth of the submersible pump 12 is 100m. When in use, turn on the submersible pump 12, and the geothermal water is produced through the water production layer 9 through the center pipe, and recharged to the recharge layer 6 through the annulus after heat exchange on the ground.

[0078] Embodiment 2

[0079] The present invention also provides a geothermal extraction and irrigation system, comprising the above-mentioned geothermal extraction and irrigation well.

[0080] Specifically, the geothermal extraction and injection system is different from the traditional method of using extraction wells and injection wells to complete the extraction and injection of geothermal water respectively. Instead, it uses the above-mentioned geothermal extraction and injection wells, which can not only realize the extraction and injection of geothermal water in a single well, simplify the operation process and subsequent maintenance, but also improve the utilization of geothermal energy and fully tap the development potential of heat storage.

[0081] 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 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, a first through hole is opened on the pipe wall of the second casing in the water production layer, and a second through hole is opened on the pipe wall of the second casing in the recharging layer; A center pipe, wherein the center pipe is passed through the first open casing and the second open casing, a packer and a water stopper are arranged between the center pipe and the second open casing, the packer is arranged between the reinjection layer and the water production layer, and the water stopper is arranged below the packer.

2. The geothermal well according to claim 1, characterized in that: The diameter of the first open casing is greater than that of the second open casing, and the first open casing is connected to the second open casing via a tail pipe suspension structure.

3. The geothermal well according to claim 1, characterized in that: The central pipe includes a first pipe and a second pipe, the diameter of the first pipe is larger than that of the second pipe, the lower end of the first pipe is located above the lower end of the open casing, and the interior of the first pipe is used for installing a submersible pump.

4. The geothermal well according to claim 3, characterized in that: The second pipe is connected to the first pipe through a reducing flange.

5. The geothermal well according to claim 3, characterized in that: The submersible pump is arranged in the first pipe and the pump pipe of the submersible pump is connected to the first pipe through an elastic centralizer.

6. The geothermal well according to claim 1, characterized in that: The packer and the water stopper are respectively arranged close to the recharging layer and the water production layer.

7. The geothermal well according to claim 1, characterized in that: A telescopic compensator is arranged above the packer, and the telescopic compensator is connected to the central pipe.

8. The geothermal well according to claim 1, characterized in that: The lower end of the central pipe is located in the water production layer.

9. The geothermal well according to claim 1, characterized in that: The packer is a pressure seal, a ball seal or an electric control seal, and the water stopper is expansion rubber.

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.

Images