Circulating water sampling system for hot dry rock stratum geothermal well

Abstract

The utility model provides a circulating water sampling system for a dry and hot rock stratum geothermal well, which relates to the technical field of geothermal exploitation devices, and comprises a geothermal well, a well sealing plate, a water sampling pipe, a recharge sleeve and a recharge pump, wherein the water sampling pipe is supported on the well sealing sleeve of the well sealing plate, the recharge sleeve is connected to the well sealing sleeve, a recharge cavity communicated with the geothermal well is formed between the inner wall of the recharge sleeve and the outside of the water sampling pipe, and a well sealing device is arranged on the outer wall of the part, located in the geothermal well, of the water sampling pipe. The geothermal well recharging device has the advantages that the recharging cavity can inject water into the upper portion of a geothermal well through the recharging pump, the water collecting pipe can collect water on the lower portion of the geothermal well at the same time, the well plugging device can promote the recharged water in the geothermal well to permeate to the lower portion of the geothermal well from rock stratum gaps in the side wall of the geothermal well, and the water on the lower portion of the geothermal well is kept in a high-temperature state. According to the circulating water collecting system, the geothermal energy collecting process of the hot dry rock stratum geothermal well can be continuously carried out, and the heat energy collecting efficiency of the hot dry rock stratum geothermal well is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of geothermal exploitation devices, in particular to a circulating water extraction system for geothermal wells in dry hot rock formations. Background Art

[0002] Geothermal wells are wells drilled for the purpose of exploiting geothermal resources. Currently, most geothermal wells are water-extracting wells, which directly extract high-temperature groundwater for use. However, for some areas with rich geothermal resources but less groundwater, drilling can only produce hot dry rock geothermal wells. The rock temperature in hot dry rock geothermal wells is high, but the amount of water is small. When using hot dry rock geothermal wells to collect heat resources, it is necessary to first inject water into the well, then seal the wellhead, and wait until the water temperature rises before collecting geothermal water for use. Currently, hot dry rock geothermal wells cannot achieve water extraction and reinjection at the same time. Therefore, a single hot dry rock geothermal well cannot collect geothermal energy continuously, which greatly reduces the thermal energy collection efficiency of the geothermal well. Utility Model Content

[0003] In view of this, in order to enable the geothermal energy collection process of hot dry rock geothermal wells to proceed continuously and improve the thermal energy collection efficiency of hot dry rock geothermal wells, the utility model provides a circulating water collection system for hot dry rock geothermal wells, including a geothermal well, a sealing plate, a water collection pipe, a reinjection sleeve and a reinjection pump.

[0004] The sealing plate is located at the wellhead of the geothermal well, a sealing sleeve is provided on the sealing plate, the upper end of the water collection pipe is supported on the upper end of the sealing sleeve, the lower end of the water collection pipe extends into the geothermal well, and a water outlet is provided on the top of the water collection pipe.

[0005] The reinjection sleeve is sleeved outside the water production pipe, and the reinjection sleeve is connected to the upper end of the sealing sleeve. A reinjection cavity is formed between the inner wall of the sealing sleeve and the outer wall of the water production pipe, and the reinjection cavity is connected to the geothermal well; the sealing sleeve is connected to a water injection pipe, and a reinjection pump is provided on the water injection pipe.

[0006] The outer wall of the water extraction pipe is provided with at least one annular well sealer, the well sealer is located in the geothermal well, and the outer wall of the well sealer supports the inner wall of the geothermal well.

[0007] Furthermore, the wellhead of the geothermal well is provided with a cementing ring made of concrete, and the sealing plate is fixed on the cementing ring.

[0008] Furthermore, the cementing ring is embedded with a plurality of embedded screws, the upper ends of the embedded screws all pass through the well sealing plate, and the upper ends of the embedded screws are all connected with fastening nuts, which are threadedly connected to the embedded screws and press the well sealing plate.

[0009] Furthermore, the upper part of the reinjection sleeve is a truncated cone structure, the upper end of the reinjection sleeve is welded to the outer wall of the water production pipe, and the lower end of the reinjection sleeve is connected to the upper end of the well sealing sleeve through a flange.

[0010] Furthermore, a support ring is provided on the inner wall of the well sealing sleeve, a support sleeve is provided on the outer wall of the water production pipe, the water production pipe passes through the support ring, and the support sleeve is supported on the support ring, and the support ring is provided with a plurality of reinjection holes connecting the reinjection chamber and the geothermal well.

[0011] Furthermore, a water intake head is provided on the top of the water sampling pipe, and at least one water intake port is provided on the water intake head.

[0012] Furthermore, a water pressure gauge is connected to the water intake head.

[0013] Furthermore, there are two well sealers, which are arranged at an interval, and an isolation filler is filled between the two well sealers.

[0014] Furthermore, a water sampling filter is provided at the lower end of the water sampling pipe, and a plurality of filter holes are distributed on the water sampling filter.

[0015] Furthermore, a re-injection filter tank is also provided on the well sealing plate, a water inlet pipe is provided on the re-injection filter tank, the water injection pipe is connected to the re-injection filter tank, a filter assembly is provided in the re-injection filter tank, the filter assembly includes an upper pressure plate, a lower pressure plate and a filter layer arranged between the upper pressure plate and the lower pressure plate, the edges of the upper pressure plate and the lower pressure plate are fixed to the inner wall of the re-injection filter tank, the water inlet pipe and the water injection pipe are respectively located below and above the filter assembly.

[0016] The utility model provides a circulating water collection system for a hot dry rock formation geothermal well, and has the following beneficial effects: the circulating water collection system comprises a geothermal well, a well sealing plate, a water collection pipe, a reinjection sleeve and a reinjection pump; wherein the water collection pipe is supported on the well sealing sleeve of the well sealing plate, the reinjection sleeve is connected to the well sealing sleeve, and a reinjection chamber connected to the geothermal well is formed between the inner wall of the reinjection sleeve and the outside of the water collection pipe; the reinjection sleeve can inject water into the upper part of the geothermal well through the reinjection pump, and the water collection pipe can collect water from the lower part of the geothermal well, so as to realize simultaneous water collection and reinjection in the hot dry rock formation geothermal well; a well sealing device is provided on the outer wall of the water collection pipe located in the geothermal well, and the well sealing device can prevent the water in the upper part of the geothermal well from directly flowing into the lower part of the geothermal well, so as to promote the reinjected water in the geothermal well to penetrate into the lower part of the geothermal well from the rock stratum gap on the side wall of the geothermal well, and this process can ensure that the water in the lower part of the geothermal well is in a high temperature state. The geothermal well can realize the recycling of geothermal water and enable the geothermal energy collection process of the hot dry rock formation geothermal well to be carried out continuously, thereby improving the thermal energy collection efficiency of the geothermal well. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a schematic diagram of the overall structure of a circulating water extraction system for a hot dry rock geothermal well according to an embodiment of the utility model.

[0018] Figure 2 It is a cross-sectional view of the wellhead position of a geothermal well of a circulating water production system for a hot dry rock geothermal well according to an embodiment of the utility model.

[0019] Figure 3 yes Figure 2 Cross-section at AA in the middle.

[0020] Figure 4 yes Figure 2 Enlarged view of point B in the middle.

[0021] Figure 5 It is a structural stereoscopic diagram of a water collection pipe, a reinjection sleeve and a water intake head of a circulating water collection system for a hot dry rock geothermal well according to an embodiment of the utility model.

[0022] In the above figure: 1-geothermal well, 11-cementing ring, 2-well sealing plate, 21-well sealing sleeve, 22-support ring, 23-reinjection through hole, 3-water production pipe, 31-support sleeve, 32-well sealing device, 33-isolation filler, 34-water production filter, 4-water intake head, 41-water intake, 5-embedded screw, 6-reinjection filter tank, 61-pressure plate, 62-filter layer, 7-reinjection sleeve, 71-water injection pipe, 8-reinjection pump. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model clearer, the implementation mode of the utility model will be further described below in conjunction with the accompanying drawings.

[0024] Please refer to Figures 1 to 5 A circulating water production system for a geothermal well in a dry hot rock formation includes a geothermal well 1, a sealing plate 2, a water production pipe 3, a reinjection sleeve 7 and a reinjection pump 8.

[0025] The geothermal well 1 is a dry hot rock formation geothermal well, the lower part of which has exploitable geothermal water, and the side wall of the geothermal well 1 is a high-temperature rock formation with pores and cracks. The sealing plate 1 is fixed to the wellhead of the geothermal well 1, and a sealing sleeve 21 is provided on the sealing plate 2. The water collection pipe 3 is arranged in the geothermal well 1, and the lower end of the water collection pipe 3 extends to the lower part of the geothermal well 1. The upper end of the water collection pipe 3 is supported on the upper end of the sealing sleeve 21. The top of the water collection pipe 3 is open, and the top of the water collection pipe 3 is a water outlet. The water in the lower part of the geothermal well 1 can be discharged from the water outlet of the water collection pipe 3 to realize the collection of geothermal water.

[0026] The reinjection sleeve 7 is sleeved on the outside of the water collection pipe 3, and the reinjection sleeve 7 is connected to the upper end of the sealing sleeve 21. In this embodiment, the upper part of the reinjection sleeve 7 is a truncated cone structure, and the inner wall diameter of the lower end of the reinjection sleeve is larger than the inner wall diameter of the upper end of the reinjection sleeve 7. The upper end of the reinjection sleeve 7 is welded to the outer wall of the water collection pipe 3, and the lower end of the reinjection sleeve 7 is connected to the upper end of the sealing sleeve 21 through a flange. A reinjection cavity is formed between the inner wall of the reinjection sleeve 7 and the outer wall of the water collection pipe 3, and the reinjection cavity is connected to the geothermal well; the sealing sleeve 21 is connected to a water injection pipe 71, and a reinjection pump 8 is arranged on the water injection pipe 71. A stop valve is also arranged on the water injection pipe 71, and the stop valve is located between the reinjection pump 8 and the reinjection sleeve 7; the reinjection pump 8 can reinject the used geothermal water into the geothermal well 1 from the gap between the outer wall of the water collection pipe 3 and the inner wall of the geothermal well 1.

[0027] The outer wall of the water production pipe 3 is provided with at least one annular well sealer 32, and the well sealer 32 is located in the geothermal well. The outer wall of the well sealer 32 supports the inner wall of the geothermal well. The well sealer 32 is located in the middle of the geothermal well 1. The well sealer 32 divides the geothermal well into an upper part and a lower part. The well sealer 32 is used to prevent the reinjected water in the upper part of the geothermal well 1 from directly flowing into the lower part of the geothermal well 1, so that the reinjected water in the geothermal well can penetrate from the cracks in the rock formations on the side walls of the geothermal well to the lower part of the geothermal well. This process can enable the reinjected water to be fully heated by the rock formations on the side walls of the geothermal well, ensuring that the water in the lower part of the geothermal well is in a high temperature state.

[0028] In the above structure, the process of the reinjection pump 8 injecting water into the upper part of the geothermal well and the process of the water collection pipe 3 collecting geothermal water in the lower part of the geothermal well can be carried out simultaneously, and the well sealing device 1 can ensure that the water in the lower part of the geothermal well is always in a high temperature state, so that the dry hot rock formation geothermal well can simultaneously produce water and reinject, so that the geothermal energy collection process of the dry hot rock formation geothermal well can be carried out continuously, thereby improving the thermal energy collection efficiency of the geothermal well.

[0029] Preferably, the wellhead of the geothermal well 1 is provided with a cementing sleeve 11 made of concrete, which can prevent the wellhead of the geothermal well 1 from collapsing. The sealing plate is fixed on the cementing sleeve 11, and the cementing sleeve 11 is embedded with a plurality of embedded screws 5, the upper ends of the embedded screws 5 all pass through the sealing plate, and the upper ends of the embedded screws 5 are connected with fastening nuts, which are threadedly connected to the embedded screws 5 and press the sealing plate, and the embedded screws 5 and the fastening nuts can enable the sealing plate to be firmly fixed to the wellhead of the geothermal well 1.

[0030] Preferably, a support ring 22 is provided on the inner wall of the well sealing sleeve 21, a support sleeve 31 is provided on the outer wall of the water production pipe, the water production pipe 3 passes through the support ring 22, and the support sleeve 31 is supported on the support ring 22, and a plurality of reinjection holes 23 connecting the reinjection chamber and the geothermal well are provided on the support ring 22.

[0031] Preferably, a water intake head 4 is further provided at the top of the water collection pipe 3, and at least one water intake port 41 is provided on the water intake head 4, and a water pressure gauge is also connected to the water intake head 4. The water intake head 4 can facilitate the use of hot water, and the water pressure gauge can detect the water pressure in the water intake head 4. A water collection filter 4 is provided at the lower end of the water collection pipe 3, and a plurality of filter holes are distributed on the water collection filter 4, and the water collection filter 4 is used to prevent solid impurities at the bottom of the geothermal well from entering the water collection pipe.

[0032] Preferably, there are two well sealers 32, which are spaced apart, and an isolation filler is filled between the two well sealers 32. The distance between the two well sealers 32 is 5-10m, and the isolation filler 33 is made of concrete. The isolation filler can prevent the geothermal well from collapsing and ensure the stability of the installation of the two well sealers 32. The distance between the two well sealers 32 is 5-10m, which can ensure that the geothermal water injected back into the lower part of the geothermal well is fully heated during its penetration.

[0033] Preferably, a re-injection filter tank 6 is also provided on the well sealing plate 2, and a water inlet pipe is provided on the re-injection filter tank 6. The water injection pipe 71 is connected to the re-injection filter tank 6. A filter assembly is provided in the re-injection filter tank 6, and the filter assembly includes two pressure plates 61, which are an upper pressure plate, a lower pressure plate and a filter layer 62 arranged between the upper pressure plate and the lower pressure plate. Water-permeable holes are distributed on the upper pressure plate and the lower pressure plate. The filter layer 62 is a filter cloth. The edges of the upper pressure plate and the lower pressure plate are fixed to the inner wall of the re-injection filter tank 6 by screws. The water in the water inlet pipe needs to pass through the filter layer 62 when entering the water injection pipe 71. The filter layer 62 is used to filter impurities in the re-injection water.

[0034] In this document, the directional words such as front, back, top, and bottom are defined by the positions of the components in the drawings and the positions of the components relative to each other, and are only for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in this application.

[0035] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A circulating water extraction system for a hot dry rock geothermal well, characterized in that: Including geothermal well, well sealing plate, water production pipe, reinjection sleeve and reinjection pump; The sealing plate is located at the wellhead of the geothermal well, a sealing sleeve is provided on the sealing plate, the upper end of the water collection pipe is supported on the upper end of the sealing sleeve, the lower end of the water collection pipe extends into the geothermal well, and a water outlet is provided at the upper end of the water collection pipe; The reinjection sleeve is sleeved outside the water production pipe, and the reinjection sleeve is connected to the upper end of the sealing sleeve, and a reinjection cavity is formed between the inner wall of the sealing sleeve and the outer wall of the water production pipe, and the reinjection cavity is connected to the geothermal well; the sealing sleeve is connected to a water injection pipe, and a reinjection pump is provided on the water injection pipe; The outer wall of the water extraction pipe is provided with at least one annular well sealer, the well sealer is located in the geothermal well, and the outer wall of the well sealer supports the inner wall of the geothermal well.

2. A circulating water extraction system for hot dry rock geothermal wells according to claim 1, characterized in that: The wellhead of the geothermal well is provided with a cementing ring sleeve made of concrete, and the sealing plate is fixed on the cementing ring sleeve.

3. A circulating water extraction system for hot dry rock geothermal wells according to claim 2, characterized in that: The cementing ring is embedded with a plurality of embedded screws, the upper ends of all the embedded screws pass through the well sealing plate, and the upper ends of the embedded screws are connected with fastening nuts, which are threadedly connected to the embedded screws, and the fastening nuts press the well sealing plate.

4. A circulating water extraction system for hot dry rock geothermal wells according to claim 2, characterized in that: The upper part of the reinjection sleeve is a truncated cone structure, the upper end of the reinjection sleeve is welded to the outer wall of the water production pipe, and the lower end of the reinjection sleeve is connected to the upper end of the well sealing sleeve through a flange.

5. The circulating water extraction system for hot dry rock geothermal wells according to claim 1, characterized in that: A support ring is provided inside the well sealing sleeve, a support sleeve is provided on the outer wall of the water production pipe, the water production pipe passes through the support ring, and the support sleeve is supported on the support ring, and the support ring is provided with a plurality of reinjection through holes connecting the reinjection chamber and the geothermal well.

6. A circulating water extraction system for hot dry rock geothermal wells according to claim 1, characterized in that: The top of the water sampling pipe is also provided with a water intake head, and the water intake head is provided with at least one water intake port.

7. A circulating water extraction system for hot dry rock geothermal wells according to claim 6, characterized in that: The water intake head is also connected to a water pressure gauge.

8. The circulating water extraction system for hot dry rock geothermal wells according to claim 1, characterized in that: There are two well sealers, which are arranged at an interval, and an isolation filler is filled between the two well sealers.

9. A circulating water extraction system for hot dry rock geothermal wells according to claim 1, characterized in that: A water sampling filter is provided at the lower end of the water sampling pipe, and a plurality of filter holes are distributed on the water sampling filter.

10. A circulating water extraction system for hot dry rock geothermal wells according to claim 1, characterized in that: The well sealing plate is also provided with a re-injection filter tank, the re-injection filter tank is provided with a water inlet pipe, the water injection pipe is connected to the re-injection filter tank, a filter assembly is provided in the re-injection filter tank, the filter assembly includes an upper pressure plate, a lower pressure plate and a filter layer arranged between the upper pressure plate and the lower pressure plate, the edges of the upper pressure plate and the lower pressure plate are fixed to the inner wall of the re-injection filter tank, the water inlet pipe and the water injection pipe are respectively located below and above the filter assembly.

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