Fracturing construction process for geothermal well and recharging well

Abstract

The application discloses a geothermal well and recharging well fracturing construction process, and determines the well position and well depth of the geothermal well according to engineering geology and hydrogeology conditions; drilling is conducted at the well position of the geothermal well, the construction of the geothermal well is conducted, and well cementation and well washing of the geothermal well are conducted; an initial value of the radius of the heat extraction influence range of the geothermal well during heat extraction is obtained; whether the initial value is smaller than a first threshold value is judged, if yes, fracturing holes are processed on the well wall of the heat extraction section in the geothermal well, and the heat extraction section is subjected to staged fracturing to form fracturing gaps; the well position and well depth of the recharging well are determined; drilling is conducted at the well position of the recharging well, the construction of the recharging well is conducted, and well cementation and well washing of the recharging well are conducted; fracturing holes are processed on the well wall of the recharging section in the recharging well, and the recharging section is subjected to staged fracturing to form fracturing gaps. The geothermal well and recharging well fracturing construction process of the embodiment of the application can improve geothermal energy flow and reduce disturbance to the stratum.

Description

Technical Field

[0001] This invention belongs to the field of geothermal energy technology, specifically relating to a fracturing construction process for geothermal wells and reinjection wells. Background Technology

[0002] Geothermal energy, as a new energy source with potential for both economic and environmental benefits, is receiving increasing attention and recognition. Currently, the development level of geothermal resources is low due to limited extraction output. Therefore, it is necessary to explore technological methods to increase geothermal production to meet the growing needs of daily life and production.

[0003] In related technologies, reinjection wells and extraction wells are arranged in pairs. Extraction wells are used to extract geothermal water and transport it to the surface for user heating or geothermal power generation. Reinjection wells are used to reinject the geothermal water after it has released heat energy back into the formation to reduce formation disturbance and achieve recycling. There is a certain distance between the reinjection wells and the extraction wells, and they are interconnected. The water flowing back through the reinjection well into the extraction range of the extraction well can easily affect the heat energy of the extracted geothermal water. Related technologies require that the reinjection wells and extraction wells maintain a sufficient distance, but this can lead to excessive injection pressure during the reinjection process, which can have a significant impact on the formation and affect its stability. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a fracturing construction process for geothermal wells and reinjection wells that can increase geothermal energy flow and reduce formation disturbance.

[0006] The fracturing construction process for geothermal wells and reinjection wells according to embodiments of the present invention includes:

[0007] Determine the location and depth of geothermal wells based on engineering geological and hydrogeological conditions;

[0008] Drilling is carried out at the location of the geothermal well to construct the geothermal well, and cementing and cleaning of the geothermal well are performed.

[0009] Obtain the initial value of the radius of the heat extraction influence range of the geothermal well during heat extraction;

[0010] If the initial value of the radius of the heat extraction influence range is less than the first threshold, then fracturing holes are processed on the well wall of the heat extraction section in the geothermal well, and the heat extraction section is segmented to form fracturing fractures, so that the radius of the heat extraction influence range of the geothermal well is greater than the first threshold when extracting heat.

[0011] Based on the radius of the heat extraction influence range of the geothermal well during heat extraction, the location and depth of the reinjection well are determined, wherein the reinjection well is located within the heat extraction influence range of the geothermal well during heat extraction.

[0012] Drilling is carried out at the location of the reinjection well to construct the reinjection well, and cementing and cleaning of the reinjection well are performed.

[0013] Obtain the initial value of the radius of the reinjection influence range of the reinjection well during reinjection;

[0014] If the initial value of the radius of the reinjection influence range is less than the second threshold, then fracturing holes are processed on the well wall of the reinjection section in the reinjection well, and the reinjection section is segmented to form fracturing fractures, so that the radius of the reinjection influence range of the reinjection well during reinjection is greater than the second threshold.

[0015] The fracturing construction process of geothermal wells and reinjection wells in the embodiments of the present invention can increase the flow rate of geothermal energy and reduce the disturbance to the formation. The distance between the geothermal well and the reinjection well is scientifically designed to achieve effective replenishment and circulation of geothermal energy, thereby improving the extraction efficiency of geothermal energy and realizing the effective circulation and replenishment of geothermal water and reinjection water within the range, thus improving the extraction efficiency of geothermal water and the reinjection efficiency of reinjection water.

[0016] In some embodiments, obtaining an initial value for the radius of the heat extraction influence range of the geothermal well during heat extraction includes the following steps:

[0017] The permeability of the heat extraction section of the geothermal well is determined based on engineering geological and hydrogeological conditions.

[0018] Multiple pumping tests were conducted on the geothermal well to obtain pumping flow rate parameters, water level change parameters in the geothermal well, and water level change parameters after pumping was stopped.

[0019] Determine the initial value of the radius of the heat extraction influence range of the geothermal well during heat extraction.

[0020] In some embodiments, obtaining an initial value for the radius of the reinjection influence range of the reinjection well during reinjection includes the following steps:

[0021] The permeability of the recharge section of the recharge well is determined based on engineering geological and hydrogeological conditions;

[0022] Multiple reinjection tests were conducted on the reinjection well to obtain reinjection pressure and flow rate parameters;

[0023] Determine the initial value of the radius of the reinjection influence range of the reinjection well during reinjection.

[0024] In some embodiments, after the step of segmented fracturing to form fracturing fractures in the reinjection section, the radius of the reinjection influence range of the reinjection well during reinjection is not less than 1 / 3 of the first threshold.

[0025] In some embodiments, the first threshold is 700m to 1000m.

[0026] In some embodiments, the distance between the reinjection well and the geothermal well is not less than 400m, and the second threshold is 250m to 400m.

[0027] In some embodiments, the projected area of ​​the reinjection influence range of the reinjection well on the horizontal plane during reinjection is S1, and the superimposed area of ​​the projected area of ​​the reinjection influence range of the reinjection section during reinjection and the projected area of ​​the heat extraction influence range of the geothermal well during heat extraction on the horizontal plane is S2, then the following condition is met: S2≥2 / 3S1.

[0028] In some embodiments, the reinjection section and the heat extraction section are located on the same geological stratum, and there are multiple reinjection wells distributed around the geothermal wells.

[0029] In some embodiments, the sum of the projected areas of the reinjection influence range of the plurality of reinjection wells on the horizontal plane during reinjection is not greater than 1 / 2 of the projected area of ​​the heat extraction influence range of the geothermal well on the horizontal plane during heat extraction.

[0030] In some embodiments, the fracturing holes and the fracturing fissures are filled with proppant;

[0031] Both the heat extraction section of the geothermal well and the reinjection section of the reinjection well have a vertical well section and a side well section. The fracturing holes are opened on the vertical well section and the side well section. During the fracturing process, the side well section is fracturing and proppant filling is carried out first, and then the vertical well section is fracturing and proppant filling is carried out. Attached Figure Description

[0032] Figure 1 This is a flowchart of the fracturing construction process for geothermal wells and reinjection wells according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram showing the locations of the geothermal well and the reinjection well in an embodiment of the present invention.

[0034] Figure label:

[0035] 1. Geothermal well; 2. Recharge well. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] like Figure 1 and Figure 2 As shown, the fracturing construction process for geothermal wells and reinjection wells according to an embodiment of the present invention includes:

[0038] S101. Determine the location and depth of the geothermal well based on engineering geological and hydrogeological conditions. Specifically, based on geological data, clarify the engineering geological conditions of the geothermal well, including the location, thickness, temperature, and production of the geothermal reservoir.

[0039] Based on geothermal geological conditions, engineering geological conditions, and environmental protection requirements, the most suitable well location should be selected to minimize the impact on the production of adjacent mines during drilling. The well depth is determined according to the geothermal reservoir conditions, and is usually 5-20m deeper than the lower end of the geothermal reservoir. Once the well depth is determined, drilling can be carried out.

[0040] S102. Drill at the location of geothermal well 1 to construct geothermal well 1, and perform cementing and well cleaning of geothermal well 1. During construction, multiple drilling operations can be performed, and casing can be run and cementing operations can be carried out separately.

[0041] S103. Obtain the initial value of the radius R of the heat extraction influence range of geothermal well 1 during heat extraction. During the construction of the geothermal well, the geological parameters of the corresponding heat-extracting strata can be obtained through sampling. After the construction of the geothermal well is completed, the corresponding test parameters are obtained through pumping tests, thereby evaluating the radius R of the heat extraction influence range of the geothermal well during heat extraction.

[0042] S104. Determine if the initial value is less than the first threshold. If so, process fracturing holes on the well wall of the heat extraction section in geothermal well 1, and perform segmented fracturing to form fracturing fractures in the heat extraction section, so that the radius of the heat extraction influence range of the geothermal well is greater than the first threshold. When the initial value of the radius of the heat extraction influence range is too small, the spacing between the reinjection well and the geothermal well is usually set too close, thereby reducing the reinjection pressure. This not only affects the heat extraction flow rate of the geothermal well and the subsequent user heating or geothermal power generation, but also causes a huge disturbance to the original flow of geothermal water in the formation, affecting the distribution of geothermal water and reinjection water in the formation.

[0043] In this embodiment, by fracturing the heat extraction section, the radius of the heat extraction influence range of the geothermal well can be increased, thereby increasing the heat extraction influence range of the geothermal well. Under the same geothermal water extraction rate, geothermal water from a larger area can converge towards the geothermal well, which in turn can reduce the disturbance to the local formation.

[0044] S105. Based on the radius of the heat extraction influence range of geothermal well 1, the location and depth of reinjection well 2 are determined. The reinjection section is located within the heat extraction influence range of the geothermal well, ensuring that although the reinjection water from the reinjection well can flow into the heat extraction influence range, it will not significantly impact the thermal energy of the extracted geothermal water. After the radius of the heat extraction influence range of the geothermal well reaches the first threshold, the location of the reinjection well can be better selected. After the reinjection water from the reinjection well flows into the formation within the heat extraction influence range, it replenishes the formation water lost due to the extraction of geothermal water, thereby reducing the impact on the thermal energy of the extracted geothermal water and achieving continuous and effective geothermal energy extraction.

[0045] S106. Drill at the location of reinjection well 2 to construct reinjection well 2, and perform cementing and well cleaning of reinjection well 2. Multiple drilling operations can be used, with casing running and cementing operations carried out separately.

[0046] S107. Obtain the initial value of the radius r of the reinjection influence range of reinjection well 2 during reinjection. During the construction of the reinjection well, the geological parameters of the corresponding reinjection strata can be obtained through sampling. After the construction of the reinjection well is completed, the corresponding test parameters are obtained through reinjection tests, and then the radius r of the reinjection influence range of the reinjection well during reinjection is evaluated.

[0047] S108. Determine whether the initial value of the radius of the reinjection influence range is less than the second threshold. If so, process fracturing holes on the well wall of the reinjection section in the reinjection well 2, and perform segmented fracturing on the reinjection section to form fracturing fractures, so that the radius of the reinjection influence range of the reinjection well during reinjection is greater than the second threshold.

[0048] This embodiment, by fracturing the reinjection section, can increase the flow direction of the reinjection water, making it easier for the reinjection water to be injected into the formation. This allows the reinjection well and the geothermal well to communicate and interact over a larger area, thereby improving reinjection efficiency, reducing reinjection pressure, and preventing excessive reinjection water pressure from disturbing the formation.

[0049] The geothermal well and reinjection well fracturing construction process of the embodiments of the present invention, through scientific and reasonable optimization design of the distance between the geothermal well and the reinjection well, can realize the effective replenishment and circulation of geothermal energy, improve the extraction efficiency of geothermal energy, realize the effective circulation and replenishment of geothermal water and reinjection water within the range, and improve the extraction efficiency of geothermal water and reinjection efficiency of reinjection water.

[0050] See Figure 1 and Figure 2 The following describes the fracturing construction process for geothermal wells and reinjection wells according to other embodiments of the present invention.

[0051] A fracturing construction process for geothermal wells and reinjection wells includes:

[0052] Based on engineering geological and hydrogeological conditions, the location and depth of geothermal wells are determined. Specifically, based on geological data, the engineering geological conditions of geothermal wells, such as the location, thickness, temperature, and production of the geothermal reservoir, are clarified.

[0053] Based on geothermal geological conditions, engineering geological conditions, and environmental protection requirements, the most suitable well location should be selected to minimize the impact on the production of adjacent mines during drilling. The well depth is determined according to the geothermal reservoir conditions, and is usually 5-20m deeper than the lower end of the geothermal reservoir. Once the well depth is determined, drilling can be carried out.

[0054] Drilling is carried out at the geothermal well site to construct the geothermal well, followed by cementing and well cleaning. Specifically, a multi-stage drilling method can be used, with casing installation and cementing operations performed separately.

[0055] Obtain the initial value of the radius of the heat extraction influence range of the geothermal well. Specifically, this includes the following steps:

[0056] The permeability of the heat extraction section of a geothermal well is determined based on engineering geological and hydrogeological conditions.

[0057] Pumping tests were conducted on the geothermal well to obtain parameters such as pumping flow rate, water level change in the geothermal well, and water level change after pumping was stopped.

[0058] Finally, based on the above parameters, or through similar simulation experiments and numerical simulation experiments, the initial value of the radius of the heat extraction influence range of the geothermal well is obtained.

[0059] During the construction of a geothermal well, geological parameters of the heat-extracting strata can be obtained through sampling. After the construction of the geothermal well is completed, relevant test parameters can be obtained through multiple pumping tests, thereby evaluating the radius of the heat extraction influence range of the geothermal well.

[0060] After obtaining the initial value of the radius of the heat extraction influence range, it is determined whether the initial value is less than the first threshold. If so, the heat extraction influence range is too small, and fracturing holes need to be processed on the well wall of the heat extraction section in the geothermal well. The heat extraction section needs to be segmented and fracturing to form fractures, so that the radius of the heat extraction influence range when the geothermal well extracts heat is greater than the first threshold. If the initial value of the radius of the heat extraction influence range is too small, the distance between the reinjection well and the geothermal well needs to be reduced to reduce excessive reinjection pressure. However, this will cause the reinjection water and geothermal water to interact and affect the thermal energy of the geothermal water. This not only affects the heat extraction flow rate of the geothermal well and the subsequent user heating or geothermal power generation, but also causes significant disturbance to the original flow of geothermal water within the formation.

[0061] Optionally, the first threshold is between 700m and 1000m. For example, the size of the first threshold is determined based on parameters such as the permeability of the formation, the thickness of the heat-extracting strata, and the expected extraction volume of geothermal water. The size of the first threshold can be 700m, 780m, 900m, 930m, or 1000m. Under normal circumstances, the radius of the heat-extracting influence range of a geothermal well will reach about 500m. Taking full account of the disturbance caused by fracturing to the formation, the embodiments of the present invention can increase the radius of the heat-extracting influence range of a geothermal well by nearly 100% through fracturing, and provide more options for the placement of reinjection wells, with greater flexibility and a wider range of choices.

[0062] In this embodiment, by fracturing the heat extraction section, the radius of the heat extraction influence range of the geothermal well can be increased, thereby increasing the heat extraction influence range of the geothermal well. Under the same geothermal water extraction rate, geothermal water from a larger area can converge towards the geothermal well, thereby reducing disturbance to the local formation.

[0063] Based on the radius of the heat extraction influence range of the geothermal well, the location and depth of the reinjection well are determined. The reinjection section is located within the heat extraction influence range of the geothermal well, so that although the reinjection water from the reinjection well can flow into the heat extraction influence range, it will not cause a significant impact on the thermal energy of the extracted geothermal water.

[0064] The distance between the reinjection well and the geothermal well should be no less than 400 meters. For example, the distance between the reinjection well and the geothermal well is 400m to 600m, and the reinjection section and the heat extraction section are located on the same geological stratum. Usually, one reinjection well is sufficient to meet the reinjection flow requirements and realize the circulation between the thermal energy well and the reinjection well.

[0065] Drilling is carried out at the location of the reinjection well to construct the reinjection well, followed by cementing and well cleaning. A multi-stage drilling method can be used, with casing installation and cementing operations performed separately.

[0066] The initial value of the radius of the reinjection influence range of the reinjection well during reinjection is obtained. During the construction of the reinjection well, geological parameters of the corresponding reinjection strata can be obtained through sampling, and the permeability of the reinjection section of the reinjection well is determined based on engineering geological and hydrogeological conditions. After the construction of the reinjection well is completed, relevant test parameters are obtained through reinjection tests, and then the radius of the reinjection influence range of the reinjection well during reinjection is evaluated. Reinjection tests are conducted on the reinjection well to obtain reinjection pressure and flow parameters, and the radius of the reinjection influence range of the reinjection well during reinjection is obtained through simulation analysis such as calculation, similar simulation tests, and numerical simulation tests.

[0067] After obtaining the initial value of the radius of the reinjection influence range, it is determined whether the initial value of the radius of the reinjection influence range is less than the second threshold. If so, fracturing holes are processed on the well wall of the reinjection section in the reinjection well, and the reinjection section is segmented to form fracturing fractures, so that the radius of the reinjection influence range of the reinjection well during reinjection is greater than the second threshold.

[0068] After the reinjection section is fracturing in stages, the reinjection influence radius of the reinjection well during reinjection shall not be less than 1 / 3 of the first threshold.

[0069] Preferably, the second threshold is between 250m and 400m, for example, the second threshold is 250m, 260m, 350m, or 400m. In this embodiment of the invention, fracturing can increase the radius of the reinjection influence range of the reinjection well, and allows for a more rational, flexible, and wider range of choices in the relative positional layout of the reinjection well and geothermal well.

[0070] The projected area of ​​the reinjection influence range of the reinjection diameter on the horizontal plane is S1. The superimposed area of ​​the projected area of ​​the reinjection influence range of the reinjection section and the heat extraction influence range of the geothermal well on the horizontal plane is S2. Then, the following condition is satisfied: S2≥2 / 3S1.

[0071] This embodiment, by fracturing the reinjection section, can increase the flow direction of the reinjection water, making it easier for the reinjection water to be injected into the formation. This allows the reinjection well and the geothermal well to communicate and interact over a larger area, thereby improving reinjection efficiency, reducing reinjection pressure, and preventing excessive reinjection water pressure from disturbing the formation.

[0072] In some embodiments of the present invention, the number of reinjection wells can also be multiple, distributed around the geothermal well. Reinjection through multiple reinjection wells can further reduce the reinjection flow rate and load of a single reinjection well. In this case, the sum of the projected areas of the reinjection influence range of multiple reinjection wells on the horizontal plane during reinjection is no greater than 1 / 2 of the projected area of ​​the heat extraction influence range of the geothermal well on the horizontal plane during heat extraction.

[0073] Multiple reinjection wells can be activated simultaneously or partially as needed, or the load of the reinjection wells can be selected according to the actual application conditions to ensure the stability of the fluid in the formation and the efficient extraction and stable thermal energy of geothermal water.

[0074] In this embodiment, proppant is filled into the fracturing holes and fractures in the heat extraction section of the geothermal well and the reinjection section of the reinjection well, thereby supporting the fractures, ensuring the stability of the formation structure, and improving the permeability of the formation.

[0075] Furthermore, both the heat extraction section of the geothermal well and the reinjection section of the reinjection well have vertical and sidewall sections. Fracturing holes are drilled in both the vertical and sidewall sections. During fracturing, the sidewall section is fracturing and proppant filling is performed first, followed by the vertical section fracturing and proppant filling. The sidewall sections are drilled at an angle to the vertical direction to extend horizontally and increase the impact range during heat extraction and reinjection.

[0076] This embodiment can increase the water output and heat output of a single well, achieve large-scale fracturing, increase the production of a single well and the final heating or power generation of users. There is sufficient distance between the reinjection well and the geothermal well, and there is a relatively large range of influence for heat extraction and reinjection. Under the premise of ensuring that the quality of the geothermal water for heat extraction remains unchanged, the heat extraction system and the reinjection system can operate more stably.

[0077] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0079] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0081] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A fracturing construction process for geothermal wells and reinjection wells, characterized in that, include: Determine the location and depth of geothermal wells based on engineering geological and hydrogeological conditions; Drilling is carried out at the location of the geothermal well to construct the geothermal well, and cementing and cleaning of the geothermal well are performed. Obtain the initial value of the radius of the heat extraction influence range of the geothermal well during heat extraction; If the initial value of the radius of the heat extraction influence range is less than the first threshold, then fracturing holes are processed on the well wall of the heat extraction section in the geothermal well, and the heat extraction section is segmented to form fracturing fractures, so that the radius of the heat extraction influence range of the geothermal well is greater than the first threshold when extracting heat. Based on the radius of the heat extraction influence range of the geothermal well during heat extraction, the location and depth of the reinjection well are determined, wherein the reinjection well is located within the heat extraction influence range of the geothermal well during heat extraction. Drilling is carried out at the location of the reinjection well to construct the reinjection well, and cementing and cleaning of the reinjection well are performed. Obtain the initial value of the radius of the reinjection influence range of the reinjection well during reinjection; If the initial value of the radius of the reinjection influence range is less than the second threshold, then fracturing holes are processed on the well wall of the reinjection section in the reinjection well, and the reinjection section is segmented to form fracturing fractures, so that the radius of the reinjection influence range of the reinjection well during reinjection is greater than the second threshold. After the reinjection section is segmented and hydraulically fractured to form hydraulic fractures, the radius of the reinjection influence range of the reinjection well during reinjection is not less than 1 / 3 of the first threshold. The projected area of ​​the reinjection influence range of the reinjection well on the horizontal plane during reinjection is S1, and the superimposed area of ​​the projected area of ​​the reinjection influence range of the reinjection section during reinjection and the projected area of ​​the heat extraction influence range of the geothermal well on the horizontal plane is S2. Then, the following condition is satisfied: S2≥2 / 3S1.

2. The fracturing construction technology for geothermal wells and reinjection wells according to claim 1, characterized in that, The process of obtaining the initial value of the radius of the heat extraction influence range of the geothermal well during heat extraction includes the following steps: The permeability of the heat extraction section of the geothermal well is determined based on engineering geological and hydrogeological conditions. Multiple pumping tests were conducted on the geothermal well to obtain pumping flow rate parameters, water level change parameters in the geothermal well, and water level change parameters after pumping was stopped. Determine the initial value of the radius of the heat extraction influence range of the geothermal well during heat extraction.

3. The fracturing construction technology for geothermal wells and reinjection wells according to claim 1, characterized in that, The steps to obtain the initial value of the radius of the reinjection influence range of the reinjection well during reinjection include the following steps: The permeability of the recharge section of the recharge well is determined based on engineering geological and hydrogeological conditions; Multiple reinjection tests were conducted on the reinjection well to obtain reinjection pressure and flow rate parameters; Determine the initial value of the radius of the reinjection influence range of the reinjection well during reinjection.

4. The fracturing construction technology for geothermal wells and reinjection wells according to any one of claims 1 to 3, characterized in that, The first threshold is 700m to 1000m.

5. The fracturing construction technology for geothermal wells and reinjection wells according to claim 4, characterized in that, The distance between the reinjection well and the geothermal well is not less than 400m, and the second threshold is 250m to 400m.

6. The fracturing construction technology for geothermal wells and reinjection wells according to claim 5, characterized in that, The reinjection section and the heat extraction section are located on the same geological stratum, and there are multiple reinjection wells distributed around the geothermal wells.

7. The fracturing construction technology for geothermal wells and reinjection wells according to claim 6, characterized in that, The sum of the projected areas of the reinjection influence range of the multiple reinjection wells on the horizontal plane during reinjection is not greater than 1 / 2 of the projected area of ​​the heat extraction influence range of the geothermal well on the horizontal plane during heat extraction.

8. The fracturing construction technology for geothermal wells and reinjection wells according to claim 1, characterized in that, The fracturing holes and the fracturing fissures are filled with proppant. Both the heat extraction section of the geothermal well and the reinjection section of the reinjection well have a vertical well section and a side well section. The fracturing holes are opened on the vertical well section and the side well section. During the fracturing process, the side well section is fracturing and proppant filling is carried out first, and then the vertical well section is fracturing and proppant filling is carried out.

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