Geothermal reservoir recharge system

Abstract

The geothermal reservoir recharge system comprises a geothermal well used for discharging geothermal water; the recharge well is connected with the geothermal well through a geothermal pipeline, the distance between the recharge well and the geothermal well is larger than or equal to 100 m, and the recharge flow of geothermal water, leading to the recharge well, of the geothermal pipeline is smaller than or equal to 100 m < 3 > / h; the filtering device comprises a sand remover, a first filter and a second filter, the filtering diameter of the second filter is smaller than that of the first filter, the sand remover, the first filter and the second filter are sequentially arranged on the geothermal pipeline in the direction away from the geothermal well, the sand remover is adjacent to the geothermal well, and the first filter and the second filter are adjacent to the recharge well; and the heat exchanger is connected with the geothermal pipeline and the heated pipeline, so that geothermal water in the geothermal pipeline can heat the working medium in the heated pipeline through the heat exchanger. Therefore, according to the geothermal reservoir recharge system, blockage of the recharge well during recharge can be reduced conveniently, and the influence on the geothermal reservoir is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geothermal energy, in particular to a geothermal reservoir recharge system. BACKGROUND

[0002] Geothermal energy is a green and clean renewable energy. In the face of the increasing scarcity of water, wind and fossil fuels and the deteriorating environment, it has become the consensus of the international community to vigorously develop geothermal energy. Geothermal resources are divided into two categories: hydrothermal type and hot dry rock type. Compared with hot dry rock type geothermal resources, hydrothermal type geothermal resources have the characteristics of low temperature, easy exploitation and high density, and are more suitable for large-scale power generation, and have become the main type of geothermal resource development. At present, the development and utilization of hydrothermal type geothermal resources worldwide is still low, and it is urgent to increase the development efforts. However, the hydrothermal type geothermal reservoir needs to be restored to the temperature. And with the large-scale exploitation of underground hot water, the "exploitation without recharge" exploitation method has led to a significant decline in the water level of underground hot water, and the direct discharge of geothermal tail water into rivers or lakes has caused pollution to surface water, soil and even shallow underground water. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art. To this end, an embodiment of the present application proposes a geothermal reservoir recharge system.

[0004] The geothermal reservoir recharge system according to an embodiment of the present application comprises:

[0005] a geothermal well, the geothermal well being configured to discharge geothermal water;

[0006] a recharge well, the recharge well being connected to the geothermal well via a geothermal pipeline, the distance between the recharge well and the geothermal well being greater than or equal to 100 meters, and the recharge flow rate of geothermal water into the recharge well via the geothermal pipeline being less than or equal to 100 m 3 / h;

[0007] a filtering device, the filtering device comprising a sand remover, a first filter and a second filter, the filter diameter of the second filter being smaller than the filter diameter of the first filter, the sand remover, the first filter and the second filter being sequentially arranged on the geothermal pipeline in a direction away from the geothermal well, the sand remover being adjacent to the geothermal well, and the first filter and the second filter being adjacent to the recharge well;

[0008] a heat exchanger, the heat exchanger being connected to the geothermal pipeline and a heated pipeline, so that the geothermal water in the geothermal pipeline can heat the working medium in the heated pipeline via the heat exchanger.

[0009] Therefore, the geothermal reservoir recharge system according to an embodiment of the present application can facilitate reducing the plugging of the recharge well during recharge and reducing the impact on the geothermal reservoir.

[0010] In some embodiments, the filtering device includes an exhaust tank, which is arranged on the geothermal pipeline and can discharge gas from the geothermal water in the geothermal pipeline.

[0011] In some embodiments, the filtering device includes a desludging device and a first pump body, and the desander, the desludging device, the exhaust tank, the first pump body, the heat exchanger, the first filter and the second filter are arranged in sequence on the geothermal pipeline in a direction away from the geothermal well.

[0012] In some embodiments, the filter diameter of the second filter is greater than or equal to 2 μm and less than or equal to 5 μm;

[0013] An automatic exhaust valve is provided on the top of the exhaust tank, and an outlet of the automatic exhaust valve is communicated with an exhaust pipe.

[0014] In some embodiments, the geothermal reservoir reinjection system includes an aeration device, which can inject inert gas into a position above the liquid level in the reinjection well.

[0015] In some embodiments, the geothermal water recharge rate from the geothermal pipeline to the recharge well is greater than or equal to 50m 3 / h and less than or equal to 100m 3 / h;

[0016] The distance between the reinjection well and the geothermal well is greater than or equal to 200 meters.

[0017] In some embodiments, the recharge flow rate of the recharge well is 50m 3 / h, the distance between the reinjection well and the geothermal well is 600 meters.

[0018] In some embodiments, there are multiple heat exchangers, and the geothermal pipeline is connected to the heated pipeline through multiple heat exchangers.

[0019] In some embodiments, the plurality of heat exchangers include a first heat exchanger and a second heat exchanger, wherein the first heat exchanger is located on the geothermal pipeline between the inlet of the geothermal pipeline and the second heat exchanger, and the second heat exchanger is located on the heated pipeline between the inlet of the heated pipeline and the first heat exchanger.

[0020] In some embodiments, the plurality of heat exchangers include a first heat exchanger and a second heat exchanger, wherein the first heat exchanger is located on the geothermal pipeline between an inlet of the geothermal pipeline and the second heat exchanger;

[0021] The heated pipeline includes a first heated pipeline, a second heated pipeline and a heat pump unit. The geothermal water in the geothermal pipeline heats the first heated pipeline through the first heat exchanger, and the geothermal water in the geothermal pipeline heats the second heated pipeline through the second heat exchanger and the heat pump unit in turn. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of a geothermal reservoir reinjection system according to an embodiment of the present invention.

[0023] Figure 2 Schematic diagram of a geothermal reservoir reinjection system according to another embodiment of the present invention.

[0024] Figure numerals: 1. geothermal well, 2. reinjection well, 3. geothermal pipeline, 4. desander, 5. decontaminator, 6. exhaust tank, 7. first pump body, 8. first heat exchanger, 9. second heat exchanger, 10. first filter, 11. second filter, 12. heated pipeline, 13. first heated pipeline, 14. second heated pipeline, 15. heat pump unit. DETAILED DESCRIPTION

[0025] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0026] The following describes the geothermal reservoir recharge system according to an embodiment of the present invention with reference to the accompanying drawings. Figure 1 and Figure 2 As shown, the geothermal reservoir reinjection system according to an embodiment of the present invention includes a geothermal well 1, a reinjection well 2, a filtering device and a heat exchanger.

[0027] Geothermal well 1 is used to discharge geothermal water, and recharge well 2 is connected to recharge well 2 via geothermal pipeline 3. A heat exchanger is connected to geothermal pipeline 3 and heated pipeline 12, allowing the geothermal water in geothermal pipeline 3 to heat the working fluid in heated pipeline 12 through the heat exchanger. This allows geothermal water discharged from geothermal well 1 to flow into geothermal pipeline 3. As the geothermal water flows through geothermal pipeline 3, the heat exchanger absorbs the heat energy from the geothermal water, heating the working fluid in heated pipeline 12. This allows the heat energy of the geothermal water to be utilized through the heat exchanger. For example, heated pipeline 12 can be a heating pipeline.

[0028] like Figure 1 and Figure 2 As shown, the filtering device includes a desander 4, a first filter 10 and a second filter 11. The filter diameter of the second filter 11 is smaller than that of the first filter 10. The first filter 10 is a coarse filter and the second filter 11 is a fine filter.

[0029] Desander 4, first filter 10, and second filter 11 are sequentially arranged on geothermal pipeline 3, moving away from geothermal well 1. Desander 4 is adjacent to geothermal well 1, while first filter 10 and second filter 11 are adjacent to recharge well 2. This allows geothermal water to enter geothermal pipeline 3 and then pass through desander 4 to remove solid particles, thereby reducing the burden on the filters.

[0030] Before the geothermal water in the geothermal pipeline 3 is recharged to the recharge well 2, it can pass through the first filter 10 and the second filter 11 in sequence to remove impurities in the geothermal water. The filtered impurities in the geothermal water can be discharged from the sewage outlets of the first filter 10 and the second filter 11. Specifically, the filter diameter of the second filter 11 is greater than or equal to 2μm and less than or equal to 5μm, thereby filtering out most suspended particles and some microorganisms, effectively reducing physical blockage caused by entering the recharge well 2, and greatly improving the recharge efficiency. For example, the geothermal pipeline 3 is made of non-metallic pipes (glass fiber reinforced plastic pipes), which reduces iron bacteria and reduces system corrosion.

[0031] like Figure 1 and Figure 2 As shown, in some embodiments, the filtration device includes an exhaust tank 6, a desander 5, and a first pump body 7. The desander 4, desander 5, exhaust tank 6, first pump body 7, heat exchanger, first filter 10, and second filter 11 are sequentially arranged on the geothermal pipeline 3 in a direction away from the geothermal well 1. The desander 5 is used to remove solid particulate impurities from the fluid. The desander 4 and desander 5 work together to further remove solid particles, thereby reducing the burden on the filters. The first pump body 7 facilitates the flow of geothermal water.

[0032] An exhaust tank 6 is installed on the geothermal pipeline 3 to exhaust gases from the geothermal water within the pipeline 3. Specifically, an automatic exhaust valve is installed on the top of the exhaust tank 6, and the outlet of the automatic exhaust valve is connected to the exhaust pipe. Installing the exhaust tank 6 allows for the removal of gases from the water, thereby removing excess gas from the recharged water. When gas accumulates to a certain level, the automatic exhaust valve promptly releases the gas into the exhaust pipe outside the tank to ensure safety.

[0033] In some embodiments, the geothermal reservoir reinjection system includes an aeration device that can inject an inert gas into the reinjection well 2 above the liquid level. This allows the well pipe above the liquid level in the reinjection well 2 to be filled with the inert gas, thereby preventing both well pipe corrosion and oxide precipitation. For example, the inert gas can be nitrogen.

[0034] In some embodiments, there are multiple heat exchangers, and the geothermal pipeline 3 is connected to the heated pipeline 12 through multiple heat exchangers. As a result, the geothermal water in the geothermal pipeline 3 can be sequentially absorbed by multiple heat exchangers, thereby improving the utilization rate of the thermal energy of the geothermal water.

[0035] like Figure 1 As shown, in some embodiments, the multiple heat exchangers include a first heat exchanger 8 and a second heat exchanger 9. The first heat exchanger 8 is located on the geothermal pipeline 3 between the inlet of the geothermal pipeline 3 and the second heat exchanger 9. This allows the geothermal water in the geothermal pipeline 3 to sequentially enter the first heat exchanger 8 and the second heat exchanger 9 as a heat source. Furthermore, since the geothermal water in the geothermal pipeline 3 serves as a heat source, the temperature of the geothermal water entering the first heat exchanger 8 is higher than the temperature of the geothermal water entering the second heat exchanger 9. The second heat exchanger 9 is located on the heated pipeline 12 between the inlet of the heated pipeline 12 and the first heat exchanger 8. This allows the geothermal water in the heated pipeline 12 to be heated sequentially by the second heat exchanger 9 and the first heat exchanger 8. The heated working fluid first enters the second heat exchanger 9 for waste heat recovery before entering the first heat exchanger 8 to be heated to a predetermined temperature, thereby reducing the waste of geothermal energy.

[0036] like Figure 2 As shown, in some embodiments, the multiple heat exchangers include a first heat exchanger 8 and a second heat exchanger 9. The first heat exchanger 8 is located between the inlet of the geothermal pipeline 3 and the second heat exchanger 9 on the geothermal pipeline 3, so that the geothermal water in the geothermal pipeline 3 can enter the first heat exchanger 8 and the second heat exchanger 9 in sequence as a heat source.

[0037] The heated pipeline 12 includes a first heated pipeline 13, a second heated pipeline 14, and a heat pump unit 15. The geothermal water in the geothermal pipeline 3 heats the first heated pipeline 13 through the first heat exchanger 8. The geothermal water in the geothermal pipeline 3 then passes through the second heat exchanger 9 and the heat pump unit 15 to heat the second heated pipeline 14. Specifically, the heat source outlet of the heat pump unit 15 is connected to the cold source inlet of the second heat exchanger 9, allowing the working fluid discharged from the heat source outlet of the heat pump unit 15 to be heated in the second heat exchanger 9. The heat source inlet of the heat pump unit 15 is connected to the cold source outlet of the second heat exchanger 9, allowing the heated working fluid discharged from the second heat exchanger 9 to be passed into the heat pump unit 15 as a heat source. The heat pump unit is used to heat the working fluid in the second heated pipeline 14 using low-grade heat (thermal energy from the geothermal water).

[0038] The suspended solids, microorganisms, chemical precipitates and gases in the geothermal water can cause blockage in the recharge well 2 during the recharge process of the recharge well 2. The filtering device of the geothermal reservoir recharge system according to the embodiment of the present application comprises a sand remover 4, an exhaust tank 6, a dirt remover 5, a first filter 10 and a second filter 11, so that most of the suspended particles and part of the microorganisms entering the recharge well 2 can be reduced, the physical blockage can be effectively reduced, and the recharge capacity can be improved.

[0039] When the recharge well 2 is close to the geothermal well 1 and the recharge flow of the geothermal water of the recharge well 2 is large, the temperature of the geothermal water produced by the geothermal well 1 can be reduced. When the distance between the recharge well 2 and the geothermal well 1 is greater than or equal to 100 meters, it can be ensured that the recharge and extraction process has no significant influence on the geothermal reservoir, so that the influence of the recharge water on the geothermal water produced by the geothermal well 1 can be reduced.

[0040] The recharge flow of the geothermal water of the geothermal pipeline 3 to the recharge well 2 is less than or equal to 100 m 3 / h. Specifically, the recharge flow of the geothermal water of the geothermal pipeline 3 to the recharge well 2 is greater than or equal to 50 m 3 / h and less than or equal to 100 m 3 / h, so that the blockage of the recharge well 2 can be reduced, the recharge efficiency can be ensured, and the influence of the recharge water on the geothermal water produced by the geothermal well 1 can be reduced. For example, the recharge flow of the recharge well 2 is 50 m 3 / h.

[0041] In some embodiments, the distance between the recharge well 2 and the geothermal well 1 is greater than or equal to 200 meters. Thus, it can be ensured that the recharge and extraction process has no significant influence on the geothermal reservoir, and it can also be ensured that the geothermal heating project can be operated stably for a long time. For example, the distance between the recharge well 2 and the geothermal well 1 is 600 meters.

[0042] In a specific embodiment, one geothermal well 1 and one recharge well 2 are drilled, the well depth of the geothermal well 1 is 1425 meters, and the well depth of the recharge well 2 is 1446 meters. The wellhead water temperature of the geothermal well 1 is 53℃, the maximum water yield is 98 m 3 / h, and the heating area supported is 71,000 square meters. The geothermal well 1 can be operated stably for 168 hours, the stable water yield of the geothermal well 1 is 50 m 3 / h to 60 m 3 / h, the recharge water yield of the recharge well 2 is 50 m 3 / h to 60 m 3 / h, 100% recharge is achieved, and the average recharge rate is increased by more than 30% compared with the current average recharge rate.

[0043] Therefore, the geothermal reservoir recharge system according to the embodiment of the present application can have the advantages of reducing the blockage of the recharge well 2 during the recharge process and reducing the influence on the geothermal reservoir.

[0044] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated thereby must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0045] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated thereby. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0046] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication or interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0048] In this disclosure, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" mean that a particular feature, structure, material, or characteristic is included in at least one embodiment or example of the present disclosure. The illustrative appearances of the above-mentioned terms in various places in the specification are not necessarily referred to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, the terminology "comprising" is used in the disclosure as comprising but not limited to, that is, it is open-ended and does not exclude the presence of additional features, structures, materials, or characteristics.

[0049] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above-described embodiments are exemplary, and are not to be interpreted as limiting the present disclosure, and the ordinary skilled in the art can make changes, modifications, replacements, and variations to the above-described embodiments within the scope of the present disclosure.

Claims

1. A geothermal reservoir recharge system, characterized in that: include: A geothermal well, wherein the geothermal well is used to discharge geothermal water; The recharge well is connected to the recharge well by a geothermal pipeline, the distance between the recharge well and the geothermal well is greater than or equal to 100 meters, and the recharge flow rate of geothermal water from the geothermal pipeline to the recharge well is less than or equal to 100m 3 / h; a filtering device, the filtering device comprising a desander, a first filter, and a second filter, wherein the filter diameter of the second filter is smaller than the filter diameter of the first filter, the desander, the first filter, and the second filter are sequentially arranged on the geothermal pipeline in a direction away from the geothermal well, the desander is adjacent to the geothermal well, and the first filter and the second filter are adjacent to the recharge well; A heat exchanger is connected to the geothermal pipeline and the heated pipeline so that the geothermal water in the geothermal pipeline can heat the working medium in the heated pipeline through the heat exchanger.

2. The geothermal reservoir recharge system according to claim 1, characterized in that: The filtering device includes an exhaust tank, which is arranged on the geothermal pipeline and can exhaust gas in the geothermal water in the geothermal pipeline.

3. The geothermal reservoir recharge system according to claim 2, characterized in that: The filtering device includes a desander and a first pump body. The desander, the desander, the exhaust tank, the first pump body, the heat exchanger, the first filter and the second filter are arranged in sequence on the geothermal pipeline in a direction away from the geothermal well.

4. The geothermal reservoir recharge system according to claim 2, characterized in that: The filter diameter of the second filter is greater than or equal to 2 μm and less than or equal to 5 μm; An automatic exhaust valve is provided on the top of the exhaust tank, and an outlet of the automatic exhaust valve is communicated with an exhaust pipe.

5. The geothermal reservoir reinjection system according to claim 1, characterized in that: The geothermal reservoir reinjection system includes an aeration device, which can inject inert gas into a position above the liquid level in the reinjection well.

6. The geothermal reservoir reinjection system according to claim 1, characterized in that: The geothermal water recharge flow rate from the geothermal pipeline to the recharge well is greater than or equal to 50m 3 / h and less than or equal to 100m 3 / h; The distance between the reinjection well and the geothermal well is greater than or equal to 200 meters.

7. The geothermal reservoir reinjection system according to claim 6, characterized in that: The recharge flow rate of the recharge well is 50m 3 / h, the distance between the reinjection well and the geothermal well is 600 meters.

8. The geothermal reservoir recharge system according to any one of claims 1 to 7, characterized in that: There are multiple heat exchangers, and the geothermal pipeline is connected to the heated pipeline through the multiple heat exchangers.

9. The geothermal reservoir reinjection system according to claim 8, characterized in that: The plurality of heat exchangers include a first heat exchanger and a second heat exchanger. The first heat exchanger is located between the inlet of the geothermal pipeline and the second heat exchanger on the geothermal pipeline. The second heat exchanger is located between the inlet of the heated pipeline and the first heat exchanger on the heated pipeline.

10. The geothermal reservoir reinjection system according to claim 8, characterized in that: The plurality of heat exchangers include a first heat exchanger and a second heat exchanger, wherein the first heat exchanger is located on the geothermal pipeline between an inlet of the geothermal pipeline and the second heat exchanger; The heated pipeline includes a first heated pipeline, a second heated pipeline and a heat pump unit. The geothermal water in the geothermal pipeline heats the first heated pipeline through the first heat exchanger, and the geothermal water in the geothermal pipeline heats the second heated pipeline through the second heat exchanger and the heat pump unit in turn.

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