Well drilling method for single well fluid storage and geothermal collection

Abstract

The invention relates to a well drilling method for single well fluid sealing and geothermal collection. The well drilling method comprises the steps that a well opening section is drilled underground to the bottom of a shallow aquifer; the second well opening section continues to be drilled till the top of the sealing layer; continuously drilling a third well section until the bottom of the geothermal water layer; a first well opening shaft is placed in the first well opening section, second well opening shafts are placed in the first well opening section and the second well opening section, third well opening shafts are placed in the three well sections, and the parts, corresponding to the sealing layer and the geothermal water layer, of the third well opening shafts are screen pipes; a first fixed edge and a second fixed edge which protrude towards the inside of the well are arranged on the inner wall of the third-section shaft; an inner well is arranged in the third-section shaft, and the top and the bottom of the inner well are supported by a first fixing edge and a second fixing edge respectively; the geothermal water ascends along the inner well, and the fluid to be sealed descends along a sealing cavity between the inner well and the third-opening shaft; a flow dividing well is arranged at the top of the third-section shaft and internally divided into a first sealing cavity, a shallow water cavity, a second sealing cavity and a hot water cavity, the two sealing cavities are communicated with the sealing cavity body, and the hot water cavity is communicated with the inner well.

Description

Technical Field

[0001] The present invention belongs to the technical field of geological storage and geothermal collection, and in particular relates to a drilling method for single-well fluid storage and geothermal collection. Background Art

[0002] Deep geological storage technology involves storing gas and liquid fluids in underground rock pores and microfractures at depths of 1,500 to 3,500 meters below the Earth's surface through deep wells. This technology allows gas and liquid fluids to be stored outside the biosphere, utilizing the sealing and degradation properties of the fourth environmental media (deep geological environments) to prevent the stored fluids from participating in human and biological material cycles. Deep geological storage wells typically range from 1,500 to 3,500 meters in depth. With increasing depth, the ground temperature rises by 3°C for every 100 meters. At a depth of 2,000 meters, the ground temperature is approximately 60°C. At this depth, the storage layer also serves as an ideal geothermal reservoir. Currently, geological storage wells are typically designed with a single function, focusing solely on fluid storage without considering geothermal resource utilization, resulting in a waste of underground thermal energy. Geothermal wells, on the other hand, often utilize U-shaped wells or dual-well circulation systems (production well + recharge well), requiring multiple wells to be drilled, resulting in high construction costs and a large land occupation. Summary of the Invention

[0003] To address the above problems, the present invention provides a drilling method for single-well fluid storage and geothermal heat collection, comprising:

[0004] S100: Drilling a first well section underground to the bottom of the shallow aquifer; then, drilling a second well section downward to the top of the sealing layer; and then drilling a third well section downward to the bottom of the geothermal water layer;

[0005] S200: placing a first wellbore in the first well section, placing a second wellbore in the first and second well sections, and placing a third wellbore in the three well sections. The parts of the third wellbore corresponding to the sealing layer and the geothermal water layer are all screen pipes, which are used to discharge the sealed fluid and collect geothermal water respectively;

[0006] S300: Below the shallow aquifer, a first fixed edge protruding into the well is provided on the inner wall of the triple-opening wellbore; between the sealing layer and the geothermal water layer is an isolation stratum, and a second fixed edge protruding into the well is provided on the inner wall of the portion of the triple-opening wellbore corresponding to the isolation stratum;

[0007] S400: An inner well is set in the three-well wellbore, the inner well passing through the two fixed sides, the top of the inner well is supported by the first fixed side, the bottom of the inner well is supported by the second fixed side, and the bottom of the inner well corresponds to the depth of the geothermal water layer;

[0008] The bottom of the inner well is open and is used to transport geothermal water; the fluid to be sealed flows downward in the sealing cavity between the outer wall of the inner well and the inner wall of the three-opening wellbore, and the inner well and the second fixed edge jointly seal the cross section of the corresponding sealing cavity;

[0009] S500: A diversion well is set at the top of the three-opening wellbore. The bottom of the diversion well is supported by the first fixed side, and the top of the diversion well is connected to the ground wellhead. The inside of the diversion well is divided into a first sealing chamber, a shallow water chamber, a second sealing chamber and a hot water chamber in a clockwise or counterclockwise direction. The two sealing chambers are connected to the top of the sealing chamber, the hot water chamber is connected to the top of the inner well, and the shallow water chamber is connected to the shallow aquifer.

[0010] The present invention uses a single well to achieve the multiple functions of geological storage and geothermal water and shallow water collection, which greatly saves drilling costs and drilling land. The present invention uses the inner well to extract the hot water flowing into the three-opening wellbore from the geothermal water layer to the diversion well, and then discharges it to the ground through the hot water cavity of the diversion well, thereby realizing the extraction of geothermal water. The fluid to be sealed first flows down through the two sealing cavities of the diversion well, and then is input into the sealing cavity between the outer wall of the inner well and the inner wall of the three-opening wellbore, so that the fluid to be sealed and the geothermal water are isolated from each other and do not affect each other. The fluid to be sealed flows downward along the sealing cavity to the sealing layer, and is injected and diffused into the sealing layer through the screen pipe there. The lower part of the inner well is connected to the second fixed edge, which supports the inner well while also sealing the bottom of the sealing cavity to prevent the fluid to be sealed from flowing through the second fixed edge and entering the geothermal water layer. The bottom of the diversion well and the top of the inner well are both supported by the first fixed edge to ensure the stability of the diversion well and the inner well. The diversion well separates the space corresponding to an open well section, making it easier for different fluids to pass through the open well section, so as to achieve separate circulation of the fluid to be sealed, geothermal water and shallow groundwater without affecting each other.

[0011] Optionally, in step S100, the inner diameter of the third well section is smaller than the inner diameter of the second well section, and the inner diameter of the second well section is smaller than the inner diameter of the first well section;

[0012] The bottom of the first well section is wider than the edge of the top of the second well section, which can support the bottom of the first wellbore; the bottom of the second well section is wider than the edge of the top of the third well section, which can support the bottom of the second wellbore.

[0013] Optionally, in step S300, a first fixed edge is provided on the inner wall of the three-opening wellbore at a position corresponding to the top of the second-opening well section. The first fixed edge is a circular ring, the outer side of which is fixed on the inner wall of the three-opening wellbore, and the inner side faces the inner well. The inner diameter of the inner side of the first fixed edge is slightly larger than the outer diameter of the inner well, so as to facilitate the inner well to pass through the center ring of the first fixed edge.

[0014] Further optionally, vertical flow channels are respectively provided at positions of the first fixed edge corresponding to the first sealing cavity and the second sealing cavity, and both flow channels pass through the first fixed edge to connect the two sealing cavities with the top of the sealing cavity body.

[0015] Optionally, a second fixed edge is provided on the inner wall of the three-opening wellbore at a position corresponding to the top of the isolation formation. The second fixed edge is in a circular ring shape, with the outer side fixed on the inner wall of the three-opening wellbore and the inner side facing the lower part of the inner well. The inner diameter of the inner side of the second fixed edge is slightly larger than the outer diameter of the inner well, so that the inner well can pass through the center ring of the second fixed edge.

[0016] Optionally, in step S400, the wellbore wall of the inner well is solid and has no through-holes, and the wellbore of the inner well is connected in sections up and down and extends along the inside of the three-opening wellbore to the geothermal water layer, and the bottom of the inner well preferably corresponds to the middle of the geothermal water layer;

[0017] There are several water pumps inside the inner well, which are evenly arranged along the length of the inner well. Water pipes are connected between the water pumps, which can lift geothermal water in multiple stages to the top of the inner well.

[0018] Further optionally, a circle of outwardly protruding first flange edge is provided at a position of the wellbore of the inner well corresponding to the top of the first fixed edge, and the lower surface of the first flange edge overlaps the upper surface of the first fixed edge.

[0019] The first flange edge is arranged at the top of the uppermost shaft of the inner well. The outer diameter of the first flange edge is larger than the inner diameter of the inner ring of the first fixed edge, so that the first flange edge is stuck on the upper surface of the first fixed edge, so that the first fixed edge supports the top of the inner well.

[0020] Further optionally, a circle of outwardly protruding second flange edge is provided at the position of the wellbore of the inner well corresponding to the top of the second fixed edge, the lower surface of the second flange edge overlaps the upper surface of the second fixed edge, and a sealing gasket is provided between the second flange edge and the upper surface of the second fixed edge for closing the second fixed edge.

[0021] Optionally, in step S500, the diversion well is located in the first opening well section, is hollow cylindrical, and has a closed bottom. The outer diameter of the diversion well is slightly smaller than the inner diameter of the third opening wellbore, so as to facilitate lowering the diversion well into the well. At the same time, the bottom of the diversion well can be placed on the first fixed edge to fix the position of the diversion well.

[0022] The diversion well is equipped with four radially distributed partitions. The inner edges of the partitions converge at the central axis of the diversion well, and the outer edges are fixed to the inner wall of the diversion well, dividing the internal space of the diversion well into four independent areas. The tops of the four areas are sealed to prevent the flow of fluids in series. The diversion well is set vertically.

[0023] Further optionally, a vertical first water pipe is provided on the bottom surface of the diversion well corresponding to the positions of the first sealing chamber and the second sealing chamber, respectively, and the first water pipe can be inserted into the corresponding flow channel; the tops of the first sealing chamber and the second sealing chamber are connected to the pumping equipment for the fluid to be sealed on the ground through pipes.

[0024] Further optionally, a second water pipe is provided at the bottom of the diversion well corresponding to the position of the hot water chamber, and the second water pipe can be inserted into the water pipe connected to the water outlet of the topmost water pump in the inner well; the top of the hot water chamber is connected to the geothermal water pumping equipment and storage equipment on the ground through a pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of a drilling method for single-well fluid storage and geothermal heat collection;

[0026] Figure 2 is a schematic diagram of a cross section of a diversion well;

[0027] Figure 3 Schematic diagram of the connection between the diversion well and the first fixed side;

[0028] Figure 4 This is a schematic diagram of the inner well being overlapped with the second fixed edge through the second flange edge.

[0029] In the accompanying drawings, 1-first well section, 2-second well section, 3-third well section, 4-screen pipe, 5-first wellbore, 6-second wellbore, 7-third wellbore, 8-first fixed edge, 9-second fixed edge, 10-inner well, 11-sealing cavity, 12-diversion well, 13-first sealing cavity, 14-shallow water cavity, 15-second sealing cavity, 16-hot water cavity, 17-flow channel, 18-water pump, 19-first flange edge, 20-second flange edge, 21-partition, 22-first water pipe, 23-second water pipe. DETAILED DESCRIPTION

[0030] This embodiment provides a drilling method for single-well fluid storage and geothermal collection, such as Figures 1-4 As shown, including:

[0031] S100: Drilling a first well section 1 underground to the bottom of the shallow aquifer; then, drilling a second well section 2 downward to the top of the sealing layer; and then drilling a third well section 3 downward to the bottom of the geothermal water layer;

[0032] S200: A first wellbore 5 is placed in the first well section 1, a second wellbore 6 is placed in the first well section 1 and the second well section 2, and a third wellbore 7 is placed in the three well sections. The portions of the third wellbore 7 corresponding to the sealing layer and the geothermal water layer are all screen pipes 4, which are used to discharge the sealed fluid and collect geothermal water, respectively.

[0033] S300: Below the shallow aquifer, a first fixed edge 8 is provided on the inner wall of the triple-opening wellbore 7, projecting into the well. Between the sealed layer and the geothermal water layer is an isolation stratum, and a second fixed edge 9 is provided on the inner wall of the portion of the triple-opening wellbore 7 corresponding to the isolation stratum, projecting into the well.

[0034] S400: An inner well 10 is set in the triple-opened wellbore 7. The inner well 10 passes through the two fixed edges. The top of the inner well 10 is supported by the first fixed edge 8, and the bottom of the inner well 10 is supported by the second fixed edge 9. The bottom of the inner well 10 corresponds to the depth of the geothermal water layer.

[0035] The bottom of the inner well 10 is open, and geothermal water can enter the inner well 10 and rise along the inner well 10; the fluid to be sealed flows downward in the sealing cavity 11 between the outer wall of the inner well 10 and the inner wall of the three-opening wellbore 7. The inner well 10 and the second fixed edge 9 jointly seal the cross section of the corresponding position of the sealing cavity 11;

[0036] S500: A diversion well 12 is set at the top of the three-opening wellbore 7. The bottom of the diversion well 12 is supported by the first fixed edge 8, and the top of the diversion well 12 is connected to the ground wellhead; the inside of the diversion well 12 is divided into a first sealing chamber 13, a shallow water chamber 14, a second sealing chamber 15 and a hot water chamber 16 in a clockwise or counterclockwise direction. The two sealing chambers are connected to the top of the sealing chamber body 11, the hot water chamber 16 is connected to the top of the inner well 10, and the shallow water chamber 14 is connected to the shallow aquifer.

[0037] Optionally, in step S100, a first well section 1 is drilled downward from the ground, and the bottom of the first well section 1 reaches the bottom of the shallow aquifer; a second well section 2 is drilled downward from the bottom of the first well section 1, and the bottom of the second well section 2 reaches the top of the sealing layer; a third well section 3 is drilled downward from the bottom of the second well section 2, and the bottom of the third well section 3 reaches the bottom of the geothermal water layer.

[0038] Further optionally, the inner diameter of the third well section 3 is smaller than the inner diameter of the second well section 2, and the inner diameter of the second well section 2 is smaller than the inner diameter of the first well section 1;

[0039] The bottom of the first well section 1 is wider than the edge of the top of the second well section 2 and can support the bottom of the first wellbore 5; the bottom of the second well section 2 is wider than the edge of the top of the third well section 3 and can support the bottom of the second wellbore 6.

[0040] Optionally, in step S200, the top heights of the first wellbore 5, the second wellbore 6 and the third wellbore 7 are the same and are all fixed at the wellhead position on the ground; the outer walls of the first wellbore 5, the second wellbore 6 and the third wellbore 7 are all cemented with mud.

[0041] In steps S100 and S200, geological exploration, drilling, wellbore setting, cementing and other operations are all performed according to existing technologies.

[0042] Optionally, in step S300, a first fixed edge 8 is provided on the inner wall of the three-opening wellbore 7 at a position corresponding to the top of the second-opening wellbore section 2. The first fixed edge 8 is annular, with an outer side fixed to the inner wall of the three-opening wellbore 7 and an inner side facing the inner well 10. The inner diameter of the inner side of the first fixed edge 8 is slightly larger than the outer diameter of the inner well 10, so that the inner well 10 can pass through the center ring of the first fixed edge 8.

[0043] The first fixed edge 8 is integrally formed with the corresponding section of the three-way shaft 7 and is made of the same material, concrete or alloy steel, to ensure that the first fixed edge 8 can provide sufficient support for the inner shaft 10 and the diversion shaft 12. When on the ground, one section of the three-way shaft 7 is machined and formed together with the corresponding first fixed edge 8.

[0044] Further optionally, vertical flow channels 17 are respectively provided at positions of the first fixed edge 8 corresponding to the first sealing cavity 13 and the second sealing cavity 15 . Both flow channels pass through the first fixed edge 8 , connecting the two sealing cavities with the top of the sealing cavity body 11 .

[0045] During geological exploration and well site design, an isolation layer is placed between the sealing layer and the geothermal water layer. The isolation layer has extremely low permeability, preventing the sealed fluid in the sealing layer from penetrating into the geothermal water layer and contaminating it. The portion of the triple-opening wellbore 7 corresponding to the isolation layer is a solid wellbore without through-holes.

[0046] Optionally, a second fixed edge 9 is provided on the inner wall of the three-opening wellbore 7 at a position corresponding to the top of the isolation formation. The second fixed edge 9 is in a circular shape, with the outer side fixed to the inner wall of the three-opening wellbore 7 and the inner side facing the lower part of the inner well 10. The inner diameter of the inner side of the second fixed edge 9 is slightly larger than the outer diameter of the inner well 10, so that the inner well 10 can pass through the center ring of the second fixed edge 9.

[0047] The second fixed edge 9 is integrally formed with the corresponding well section of the three-opening well shaft 7 and is made of the same material, concrete or alloy steel, to ensure that the second fixed edge 9 can provide sufficient support for the inner well 10. When on the ground, one well section of the three-opening well shaft 7 is machined and formed together with the corresponding second fixed edge 9.

[0048] Optionally, in step S400, the wellbore wall of the inner well 10 is solid and has no through holes. The wellbore of the inner well 10 is connected in sections up and down and extends along the inside of the three-opening wellbore 7 to the geothermal water layer. The bottom of the inner well 10 preferably corresponds to the middle of the geothermal water layer.

[0049] Several water pumps 18 are provided inside the inner well 10 , and the water pumps 18 are evenly arranged along the length direction of the inner well 10 . Water pipes are connected between the water pumps 18 , and the geothermal water can be lifted to the top of the inner well 10 in multiple stages through the water pumps.

[0050] The outlets and inlets of adjacent pumps are connected by water pipes to transfer geothermal water between them. The number of pumps is determined based on the depth of the geothermal layer and the pump head. For example, the maximum head of a domestic deep-well pump is 400m, so deep-well pumps can be installed at a maximum interval of 400m.

[0051] Further optionally, a circle of outwardly protruding first flange edge 19 is provided at a position of the wellbore of the inner well 10 corresponding to the top of the first fixed edge 8 , and the lower surface of the first flange edge 19 overlaps the upper surface of the first fixed edge 8 .

[0052] The first flange edge 19 is arranged at the top of the uppermost shaft of the inner well 10. The outer diameter of the first flange edge 19 is larger than the inner diameter of the inner ring of the first fixed edge 8, so that the first flange edge 19 cannot pass through the center ring of the first fixed edge 8, but is stuck on the upper surface of the first fixed edge 8, so that the first fixed edge 8 supports the top of the inner well 10.

[0053] Further optionally, a circle of outwardly protruding second flange edge 20 is provided at the position of the wellbore of the inner well 10 corresponding to the top of the second fixed edge 9, the lower surface of the second flange edge 20 overlaps the upper surface of the second fixed edge 9, and a sealing gasket is provided between the second flange edge 20 and the upper surface of the second fixed edge 9 for closing the second fixed edge 9.

[0054] The second flange 20 can be a connecting component at the connection between the upper and lower inner wells 10. The outer diameter of the second flange 20 is larger than the inner diameter of the inner ring of the second fixed edge 9, so that the second flange 20 cannot pass through the center ring of the second fixed edge 9, but is stuck on the upper surface of the second fixed edge 9. The deadweight of the inner well 10 can compress the sealing gasket. The second fixed edge 9 cooperates with the second flange 20 to seal the cross-section of the sealing cavity 11, so that the fluid in the sealing cavity 11 cannot continue to flow downward through the second fixed edge 9. That is, the fluid to be sealed is blocked above the second fixed edge 9 and cannot enter the geothermal water layer along the three-opening wellbore 7. Because the fluid is pressurized and transported when it is sealed, the fluid has a certain pressure in the sealing cavity 11. When the fluid flows downward and reaches the second fixed edge 9, the pressure of the fluid will strengthen the squeezing between the second flange 20 and the second fixed edge 9, further strengthening the seal there.

[0055] Optionally, in step S500, the diversion well 12 is located in the first opening well section 1, and the diversion well 12 is hollow cylindrical with a closed bottom. The outer diameter of the diversion well 12 is slightly smaller than the inner diameter of the third opening wellbore 7, so as to facilitate lowering the diversion well 12 into the well. At the same time, the bottom of the diversion well 12 can be placed on the first fixed edge 8 to fix the position of the diversion well 12.

[0056] Four radially spaced baffles 21 are installed within diversion well 12. The inner edges of these baffles 21 lie along the central axis of diversion well 12, while the outer edges are fixedly connected to the inner wall of diversion well 12. These baffles divide the interior of diversion well 12 into four independent zones. These zones are sealed at the top to prevent fluid flow from flowing in series. The volumes of these four zones can be equal or different, depending on the flow rates of the fluid to be stored, geothermal water, and shallow groundwater.

[0057] Further optionally, a vertical first water pipe 22 is provided on the bottom surface of the diversion well 12 at positions corresponding to the first sealing chamber 13 and the second sealing chamber 15, respectively, and the first water pipe 22 can be inserted into the corresponding flow channel 17; the tops of the first sealing chamber 13 and the second sealing chamber 15 are connected to the pumping equipment for the fluid to be sealed on the ground through pipes.

[0058] Optionally, a second water conduit 23 is provided at the bottom of the diversion well 12, corresponding to the hot water chamber 16. This second water conduit 23 can be inserted into a water pipe connected to the water outlet of the topmost water pump in the inner well 10. The top of the hot water chamber 16 is connected to the groundwater pumping and storage equipment via a pipe. A water pump and water pipe can also be installed inside the hot water chamber to transport the geothermal water upward.

[0059] The diversion well 12 is integrally formed with the partition 21, two first water conduits 22, and a second water conduit 23. A sealing gasket is installed on the outer wall of the top of the first water conduit 22 (i.e., the lower surface close to the bottom of the diversion well 12). When lowering the diversion well 12, align the first water conduit 22 with the corresponding flow channel, and the second water conduit 23 with the corresponding water pipe (also serving as a positioning function). The diversion well 12 uses its own weight to compress the sealing gaskets on the first and second water conduits 22, 23, ensuring that the pressurized fluid to be sealed does not leak through the first water conduit 22 and flow channel, and that the geothermal water transported by the inner well 10 does not leak through the second water conduit 23.

[0060] Optionally, after step S200, the following perforating step is further included: using a perforating gun to perforate the three wellbore layers within the corresponding section of the first wellbore section, with the perforation area preferably corresponding to the sidewall of the shallow water cavity of the diversion well, connecting the shallow aquifer to the diversion well area; in step S500, the sidewall of the shallow water cavity is provided with a plurality of through holes, connecting the shallow aquifer to the interior of the shallow water cavity. The above perforating step simultaneously perforates the first, second, and third wellbores within the first wellbore section. Existing technology can simultaneously perforate the three wellbore sidewall layers in a single perforation.

[0061] The bottom surface of the diversion well 12 is provided with an upwardly recessed groove corresponding to the position of the inner well 10 and the first flange edge 19. When the diversion well 12 is placed on the first fixed edge 8, the bottom surface of the diversion well 12 can form a good connection and fit with the inner well 10, the first flange edge 19, and the upper surface of the first fixed edge 8, and both the diversion well 12 and the inner well 10 are stable. The bottom surface of the diversion well 12 is provided with a sealing gasket, so that the shallow groundwater between the outer wall of the diversion well in the first opening section and the inner wall of the third opening wellbore cannot flow beyond the first fixed edge to the second opening section. Instead, it can only enter the shallow water cavity and be pumped to the surface.

Claims

1. A drilling method for single-well fluid storage and geothermal heat collection, characterized in that: include: S100: Drilling a first well section underground to the bottom of the shallow aquifer; then, drilling a second well section downward to the top of the sealing layer; and then drilling a third well section downward to the bottom of the geothermal water layer; S200: A first wellbore is placed in the first well section, a second wellbore is placed in the first and second well sections, and a third wellbore is placed in the three well sections. The parts of the third wellbore corresponding to the sealing layer and the geothermal water layer are all screen pipes; S300: Below the shallow aquifer, a first fixed edge protruding into the well is provided on the inner wall of the triple-opening wellbore; between the sealing layer and the geothermal water layer is an isolation stratum, and a second fixed edge protruding into the well is provided on the inner wall of the portion of the triple-opening wellbore corresponding to the isolation stratum; S400: An inner well is set in the three-well wellbore, the inner well passing through the two fixed sides, the top of the inner well is supported by the first fixed side, the bottom of the inner well is supported by the second fixed side, and the bottom of the inner well corresponds to the geothermal water layer; The bottom of the inner well is open and is used to transport geothermal water. The fluid to be sealed flows downward in the sealing cavity between the outer wall of the inner well and the inner wall of the three-opening wellbore. The inner well and the second fixed edge jointly seal the corresponding cross section of the sealing cavity. S500: A diversion well is set at the top of the three-opening wellbore. The inside of the diversion well is divided into a first sealing chamber, a shallow water chamber, a second sealing chamber and a hot water chamber. The two sealing chambers are connected to the sealing chamber body, the hot water chamber is connected to the inner well, and the shallow water chamber is connected to the shallow aquifer.

2. The drilling method for single-well fluid storage and geothermal heat collection according to claim 1, characterized in that: In step S100, the inner diameter of the third well section is smaller than the inner diameter of the second well section, and the inner diameter of the second well section is smaller than the inner diameter of the first well section; The bottom of the first well section is wider than the edge of the top of the second well section, which can support the bottom of the first wellbore; the bottom of the second well section is wider than the edge of the top of the third well section, which can support the bottom of the second wellbore.

3. The drilling method for single-well fluid storage and geothermal heat collection according to claim 1, characterized in that: In step S300, a first fixed edge is provided at a position on the inner wall of the three-opening wellbore corresponding to the top of the second-opening wellbore section. The first fixed edge is in the form of a circular ring, with an outer side fixed to the inner wall of the three-opening wellbore and an inner side facing the inner wellbore. The inner diameter of the inner side of the first fixed edge is slightly larger than the outer diameter of the inner wellbore to facilitate the inner wellbore passing through the center ring of the first fixed edge. A second fixed edge is provided on the inner wall of the three-opening wellbore at a position corresponding to the top of the isolation formation. The second fixed edge is in a circular ring shape, with the outer side fixed on the inner wall of the three-opening wellbore and the inner side facing the lower part of the inner well. The inner diameter of the inner side of the second fixed edge is slightly larger than the outer diameter of the inner well, so that the inner well can pass through the center ring of the second fixed edge.

4. The drilling method for single-well fluid storage and geothermal heat collection according to claim 3, characterized in that: Vertical flow channels are respectively provided at positions of the first fixed edge corresponding to the first sealing cavity and the second sealing cavity. Both flow channels pass through the first fixed edge to connect the two sealing cavities with the top of the sealing cavity body.

5. The drilling method for single-well fluid storage and geothermal heat collection according to claim 4, characterized in that: In step S400, the inner wellbore is connected in sections up and down and extends along the inside of the three-opening wellbore to the middle of the geothermal water layer; There are several water pumps inside the inner well, which are evenly arranged along the length of the inner well. Water pipes are connected between the water pumps, which can lift geothermal water in multiple stages to the top of the inner well.

6. The drilling method for single-well fluid storage and geothermal heat collection according to claim 4, characterized in that: A first flange edge protruding outward is provided at a position of the wellbore of the inner well corresponding to the top of the first fixed edge, and the lower surface of the first flange edge overlaps the upper surface of the first fixed edge; The first flange edge is arranged at the top of the uppermost shaft of the inner well. The outer diameter of the first flange edge is larger than the inner diameter of the inner ring of the first fixed edge, so that the first flange edge is stuck on the upper surface of the first fixed edge, so that the first fixed edge supports the top of the inner well.

7. The drilling method for single-well fluid storage and geothermal heat collection according to claim 4, characterized in that: The wellbore of the inner well is provided with a circle of outwardly protruding second flange edge at the position corresponding to the top of the second fixed edge. The lower surface of the second flange edge overlaps the upper surface of the second fixed edge. A sealing gasket is provided between the second flange edge and the upper surface of the second fixed edge for closing the second fixed edge.

8. The drilling method for single-well fluid storage and geothermal heat collection according to claim 5, characterized in that: In step S500, the diversion well is located in the first opening section. The diversion well is hollow cylindrical and has a closed bottom. The outer diameter of the diversion well is slightly smaller than the inner diameter of the third opening wellbore to facilitate lowering the diversion well into the well. At the same time, the bottom of the diversion well can be placed on the first fixed edge to fix the position of the diversion well. Four radially distributed partitions are installed inside the diversion well. The inner edges of the partitions converge at the central axis of the diversion well, and the outer edges are fixedly connected to the inner wall of the diversion well, dividing the internal space of the diversion well into four independent areas. The tops of the four areas are closed to prevent fluid serialization.

9. The drilling method for single-well fluid storage and geothermal heat collection according to claim 8, characterized in that: A vertical first water pipe is provided at the bottom of the diversion well corresponding to the first sealing chamber and the second sealing chamber, respectively, and the first water pipe can be inserted into the corresponding flow channel; the tops of the first sealing chamber and the second sealing chamber are connected to the pumping equipment for the fluid to be sealed on the ground through pipelines.

10. The drilling method for single-well fluid storage and geothermal heat collection according to claim 8, characterized in that: A second water pipe is provided at the bottom of the diversion well corresponding to the position of the hot water chamber, and the second water pipe can be inserted into the water pipe connected to the water outlet of the topmost water pump in the inner well; the top of the hot water chamber is connected to the geothermal water pumping equipment and storage equipment on the ground through a pipeline.

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