Balanced geothermal energy transfer loop

Abstract

A system and method for geothermal heat generation. The balanced geothermal energy transfer loop includes a first wellbore and a second wellbore extending from the earth's surface to a geothermal formation in the earth, and a plurality of balanced open-hole circuits extending through the geothermal formation between the first wellbore and the second wellbore, forming a substantially sealed closed loop. Each of the plurality of circuits is designed or modified to have substantially equal circuit parameters. The circuit parameters may include one or more of a circuit fluid velocity, a circuit pressure drop, a circuit volume, and / or a circuit length. The circuit parameters may include a circuit length and volume, and the circuit connects the supply / return wells in a first-out / last-in configuration.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 306,555, filed February 4, 2022, which is incorporated by reference herein in its entirety.

[0002] Field The present disclosure relates generally to geothermal energy and geothermal wells. More particularly, the present disclosure relates to advanced, closed-loop, geothermal energy and geothermal wells. [Background technology]

[0003] background Extracting energy from conventional geothermal wells relies on tapping into hot aquifers beneath the earth's surface. The problem is that hot aquifers are not easily accessible.

[0004] Enhanced geothermal wells are placed in subsurface formations with low porosity and permeability, and then fracturing (or "fracking") them to increase permeability in order to increase flow within the aquifer. The problem is that fracturing the formations can cause induced seismicity and significant water loss.

[0005] Advanced geothermal systems such as closed-loop configurations can provide tunable generation and transmission in any geological formation that has heat and do not require access to an aquifer. However, attempts to implement closed-loop designs have not been very successful due to the configuration of downhole loop designs currently being tested.

[0006] Therefore, it is desirable to develop advanced geothermal well configurations and / or closed loop improvements. Summary of the Invention [Problem to be solved by the invention]

[0007] overview It is an object of the present disclosure to eliminate or mitigate at least one disadvantage of previous geothermal well and / or closed loop designs.

[0008] The use of a flow balanced design can increase the amount of heat energy that can be extracted as opposed to a non-flow balanced design. A balanced system provides substantially equal flow rates through the horizontal circuits without increasing the pumping burden. Non-balanced systems have various challenges that can arise due to the uneven flow rates, such as increased pumping burden, variability in heat transfer capacity throughout the circuit, and no feasible means of calculating heat transfer for exposed surfaces within the loop.

[0009] If the flow is balanced, it may be possible to significantly increase the transfer of heat from the formation to the wellbore. [Means for solving the problem]

[0010] In a first aspect, the disclosure provides a system including: a first wellbore extending from the earth's surface to a geothermal formation in the earth, the first wellbore including a lateral section within the formation; a second wellbore extending from the earth's surface to a geothermal formation in the earth, the second wellbore including a lateral section within the formation in the earth; and a plurality of open-hole circuits extending between the lateral section of the first wellbore and the lateral section of the second wellbore, wherein the first wellbore, the second wellbore, and the plurality of circuits form a substantially closed loop, and the plurality of circuits are balanced.

[0011] In one disclosed embodiment, the multiple circuits include one or more of substantially equal circuit velocities, substantially equal circuit pressure drops, substantially equal circuit lengths, substantially equal circuit volumes, substantially equal resistances, ΔP / flow, and combinations thereof.

[0012] In one disclosed embodiment, the circuit parameters of the multiple circuits are substantially matched.

[0013] In one disclosed embodiment, the circuit parameters include one or more of the following: circuit fluid velocity, circuit pressure drop, circuit length, circuit volume, resistance, ΔP / flow rate, and combinations thereof.

[0014] In one disclosed embodiment, the circuit parameters include fluid velocity in the circuit and length of the circuit.

[0015] In one disclosed embodiment, a plurality of open-hole circuits connect a first wellbore and a second wellbore in a first-out / last-in configuration and flow throughout the plurality of open-hole circuits is balanced.

[0016] In one disclosed embodiment, the system further includes a heat exchange adapted to extract thermal energy from the working fluid circulated through the multiple open well circuits.

[0017] In a further aspect, the disclosure provides a method including providing a first wellbore extending from the earth's surface to a geothermal formation in the earth, the first wellbore including a lateral section within the formation; providing a second wellbore extending from the earth's surface to a geothermal formation in the earth, the second wellbore including a lateral section within the formation; providing a plurality of open-hole circuits extending between the lateral section of the first wellbore and the lateral section of the second wellbore, wherein the first wellbore, the second wellbore, and the plurality of circuits form a substantially closed loop, the plurality of circuits being balanced, and circulating a working fluid through the substantially closed loop to transport thermal energy from the geothermal formation in the earth to the surface.

[0018] In one disclosed embodiment, the multiple circuits include one or more of substantially equal circuit fluid velocities, substantially equal circuit pressure drops, substantially equal circuit lengths, substantially equal circuit volumes, substantially equal resistances, ΔP / flow rates, and combinations thereof.

[0019] In one disclosed embodiment, the method further includes calculating circuit parameters of a first circuit of the plurality of circuits and adapting remaining circuits of the plurality of circuits, respectively, to substantially match the circuit parameters.

[0020] In one disclosed embodiment, the circuit parameters include one or more of the following: circuit fluid velocity, circuit pressure drop, circuit volume, circuit length, circuit resistance, ΔP / flow rate, and combinations thereof.

[0021] In one disclosed embodiment, the method further includes calculating circuit parameters of a first circuit of the plurality of circuits and modifying remaining circuits of the plurality of circuits, respectively, to substantially match the circuit parameters.

[0022] In one disclosed embodiment, the circuit parameters include one or more of the following: circuit fluid velocity, circuit pressure drop, circuit length, circuit volume, circuit resistance, ΔP / flow rate, and combinations thereof.

[0023] In one disclosed embodiment, modifying each remaining circuit of the plurality of circuits includes enlarging at least a portion of at least one of the plurality of circuits.

[0024] In one disclosed embodiment, the working fluid of the loop is circulated at least in part by thermosiphoning.

[0025] In one disclosed embodiment, the method further includes using at least a portion of the thermal energy to provide heating to a user.

[0026] In one disclosed embodiment, the method further includes using at least a portion of the thermal energy to generate electricity.

[0027] In one disclosed embodiment, the circuit parameters include fluid velocity in the circuit and length of the circuit.

[0028] In one disclosed embodiment, a method includes connecting a first wellbore and a second wellbore in a first-out / last-in configuration with a plurality of open-hole circuits.

[0029] In one disclosed embodiment, the flow across multiple open well circuits is balanced.

[0030] In one disclosed embodiment, the balancing includes one or more of substantially equal circuit fluid velocities, substantially equal circuit pressure drops, substantially equal circuit lengths, substantially equal circuit volumes, and combinations thereof.

[0031] In one disclosed embodiment, circuit parameters of a first circuit of the plurality of circuits are predetermined, and each of the remaining circuits of the plurality of circuits is adapted to substantially match the circuit parameters.

[0032] In one disclosed embodiment, the circuit parameters include one or more of: circuit fluid velocity, circuit pressure drop, circuit volume, circuit length, and combinations thereof.

[0033] In one disclosed embodiment, circuit parameters of a first circuit of the plurality of circuits are calculated and each of the remaining circuits of the plurality of circuits is modified to substantially match the circuit parameters.

[0034] In one disclosed embodiment, the circuit parameters include one or more of: circuit fluid velocity, circuit pressure drop, circuit volume, and combinations thereof.

[0035] In one disclosed embodiment, the modification includes enlarging at least a portion of at least one of the plurality of circuits.

[0036] In one disclosed embodiment, a method includes circulating a working fluid through a substantially sealed closed loop to transport thermal energy / heat from a geothermal formation within the earth to the surface.

[0037] In one disclosed embodiment, the balancing includes one or more of substantially equal circuit velocities, substantially equal circuit pressure drops, substantially equal circuit lengths, substantially equal circuit volumes, and combinations thereof.

[0038] In one disclosed embodiment, the circuit parameters of the multiple circuits are substantially matched to one another, i.e., the circuit parameters are substantially equal between the multiple circuits.

[0039] In one disclosed embodiment, the circuit parameters include one or more of: circuit fluid velocity, circuit pressure drop, circuit length, circuit volume, and combinations thereof.

[0040] In one disclosed embodiment, the circuit parameters include fluid velocity in the circuit and length of the circuit.

[0041] In one disclosed embodiment, a plurality of open-hole circuits connect a first wellbore and a second wellbore in a first-out / last-in configuration and flow throughout the plurality of open-hole circuits is balanced.

[0042] In one disclosed embodiment, in addition to the circuits being substantially equal in length and volume, they connect the supply / return wells in a first-out / last-in configuration, thereby creating a naturally balanced flow throughout all the circuits.

[0043] Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.

[0044] BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0045] [Figure 1] FIG. 1 is a simplified plan view of the closed loop wellbore system of the present disclosure. [Diagram 2] FIG. 1 is a plan view of a closed loop wellbore system (embodiment i) of the present disclosure. [Diagram 3] FIG. 3 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 4] FIG. 3 is a front cross-sectional view of the closed loop wellbore system of FIG. [Diagram 5] FIG. 1 is a plan view of a closed loop wellbore system (embodiment ii) of the present disclosure. [Figure 6] FIG. 6 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 7] FIG. 6 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 8] FIG. 1 is a plan view of a closed loop wellbore system (embodiment iii) of the present disclosure. [Figure 9] FIG. 9 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 10] FIG. 9 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 11] FIG. 1 is a plan view of a closed loop wellbore system (embodiment 1A) of the present disclosure. [Figure 12] FIG. 12 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 13] FIG. 12 is a front cross-sectional view of the closed loop wellbore system of FIG. [Figure 14] FIG. 1B is a plan view of a closed loop wellbore system of the present disclosure (embodiment 1B). [Figure 15] FIG. 15 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 16] FIG. 15 is a front cross-sectional view of the closed loop wellbore system of FIG. [Figure 17] FIG. 2A is a plan view of a closed loop wellbore system of the present disclosure (embodiment 2A). [Figure 18] FIG. 18 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 19] FIG. 18 is a front cross-sectional view of the closed loop wellbore system of FIG. [Figure 20] FIG. 2B is a plan view of a closed loop wellbore system of the present disclosure (embodiment 2B). [Figure 21] FIG. 21 is a side cross-sectional view of the closed loop wellbore system of FIG. [Figure 22] FIG. 21 is a front cross-sectional view of the closed loop wellbore system of FIG. [Diagram 23] FIG. 1 is a plan view of a closed loop wellbore system (embodiment 3). [Figure 24] FIG. 24 is a side cross-sectional view of the closed loop wellbore system of FIG. [Diagram 25] FIG. 24 is a front cross-sectional view of the closed loop wellbore system of FIG. [Figure 26] FIG. 24 is a cross-sectional perspective view of the closed loop well system of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Detailed Description Generally, the present disclosure provides methods and systems for advanced geothermal well and / or closed loop configurations.

[0047] The heat transfer solution may be conveyed as a loop working fluid through the loop at a substantially equal flow rate throughout multiple circuits connecting two vertical wellbores having equal resistance. The heat transfer fluid may be one of any suitable fluid, for example, water, water / glycol, or supercritical CO2. 2 may include.

[0048] A surface boost pump may be required to initiate flow. Once flow is initiated, the balanced loop design and temperature differential can initiate or maintain a thermosiphoning effect. The thermosiphoning effect may contribute to reduced pumping burden.

[0049] As the low temperature heat transfer fluid from the surface displaces the high temperature heat transfer fluid located in the loop, the heat transfer fluid absorbs heat from the surrounding rocks and is forced back through the loop circuit to the surface where it can be utilized for various purposes.

[0050] The temperature can be monitored and simply the fluid velocity can be controlled to maximize heat transfer. The heat transfer solution can be selected or modified to avoid or induce a phase change.

[0051] In an exemplary embodiment, the temperature in the target zone may range from 50° C. to over 200° C. and may vary around the world. The high temperature heat transfer solution may be utilized in a variety of applications, such as for direct or indirect heating and / or cooling, and / or power generation, and / or other thermal uses, and / or combinations thereof. Energy may be used or converted using process cycles, for example electricity may be generated using process cycles such as flash steam, double flash, Organic Rankine Cycle (ORC), or other processes depending on the enthalpy of the loop solution.

[0052] In some embodiments, the available heat in the high temperature loop solution may be relatively low temperature, e.g., 50°C to 70°C. In such cases, low grade heat applications such as district heating, site specific applications such as aquaculture, greenhouse heating or process heating / cooling are ideal end uses for a stable heat source. If electricity with low enthalpy of heat is required, heat extraction for cogeneration or process cycles such as the Carnot engine can be used to generate electricity for delivery to nearby users and / or for grid delivery with or without storage before delivery.

[0053] Thermal energy extracted from the loop solution can be used to return the cryogenic fluid downhole to repeat the cycle. The energy to power the boost pump and / or process cycle and / or auxiliary equipment can be provided by the system itself, providing a zero carbon emissions system and / or a net negative carbon emissions system taking into account the materials and construction of the system.

[0054] Several procedures may be used to complete similar or the same well design. In one disclosed embodiment, the wells, hereinafter referred to as the first well and the second well, may be drilled from the same well pad. EXAMPLES

[0055] Example 1 1, in the system 10 of the present disclosure, from a well site 20, a first wellbore 40 may be drilled using a directional drilling tool to the true vertical depth (TVD) of the formation and landed at approximately 90 degrees. The first wellbore 40 may be cased to an intermediate casing point (ICP), identified as the ICP 50 of the first wellbore, after which drilling may continue and the hole may be opened while maintaining approximately 90 degrees for the length of the first wellbore 40 to the tip 60 of the first wellbore 40.

[0056] From the well site 20, a second well 70 may be drilled at about 90 degrees to a similar TVD, with a well separation between the first well 40 and the second well 70 being, for example, on the order of about 1000 m. The second well 70 may then be cased to an ICP, i.e., the ICP 80 of the second well. In drilling the second well 70, a well trail may be followed that allows for an open hole sidetrack point before heading towards the tip 60 of the first well 40.

[0057] In one disclosed embodiment, multiple circuits 100 may extend through the formation 110 between the first well 40 and the second well 70 to increase the transfer of heat from the formation 110, for example, to the first well 40, the second well 70, and a heat transfer fluid circulated through one or more of the multiple circuits 100. In a given system, the number of circuits 100 may be n, where 2≦n≦y. For simplicity of illustration, n=4, i.e., four (4) circuits 100 or "legs," are shown as 100-1, 100-2, 100-3, 100-4, by way of example only. The maximum number of circuits 100 may be much greater than four, e.g., y may be unlimited. However, practically / physically speaking, the number of circuits 100 extending between the first well 40 and the second well 70 can be selected or predetermined to be, for example, between 2 and 200, between 2 and 100, between 2 and 75, between 2 and 50, between 2 and 40, between 2 and 30, between 2 and 25, between 2 and 20, and / or between 2 and 10.

[0058] At the tip 60 of the first wellbore (see region 40D in FIG. 1 ), a guide such as magnetic ranging technology can be used to guide the circuit 100-1 of the second wellbore 70 to the first wellbore 40 to complete the connection (region 70A to region 40D in FIG. 1 ). Then, drilling can be pulled back to a sidetrack point (region 70B in FIG. 1 ) and an open hole sidetrack can be performed to form the circuit 100-2. The circuit 100-2 of the second wellbore 70 can be drilled forward (region 70A to region 70B in FIG. 1 ) and then drilled toward the first wellbore 40 (region 70B to region 40C in FIG. 1 ) to form a sidetrack point and connect (region 70B to region 40C in FIG. 1 ) using magnetic ranging technology.

[0059] After the second circuit 100-2 is excavated, calculations and / or measurements and / or other determinations can be made to determine the volume in the second circuit 100-2 compared to the first circuit 100-1, and a string hole opener can be used to open a portion of the second circuit 100-2 to match within a selected difference, such as, for example, no more than about 10 percent of the volume of the first circuit 100-1.

[0060] Excavation can then be backed up to the sidecut point of the second circuit 100-2, and the process repeated, including volume matching, for a third circuit 100-3 (from area 70C to area 40B in FIG. 1) and a fourth circuit 100-4 (from area 70D to area 40A in FIG. 1). In one disclosed embodiment, the lengths of the circuits 100 can be as close to each other as possible.

[0061] Thus, if the diameter and length of the circuits 100 are symmetrical, substantially equal resistance to flow can be achieved throughout the circuits. It is also appropriate that the spacing between the circuits at the exit points be comparable to the distance between the circuits at the entry points.

[0062] Example 2 2-4 (embodiment i), a first wellbore 40 may be drilled using a directional drilling tool to the TVD 120 of the formation and landed at approximately 90 degrees. The illustrated TVD of 4500 m is merely an example. The first wellbore 40 may be cased to this point, i.e., the ICP 50 of the first wellbore, and then drilling may continue while maintaining approximately 90 degrees for the length of the first wellbore 40.

[0063] The second well 70 can then be drilled slightly, e.g., about 100-200 m higher TVD to about 80 degrees, with a well separation 130 between the first well 40 and the second well 70 of, e.g., about 1000 m. The second well 70 can then be cased up to the ICP 80 of the second well.

[0064] After the second well 70 is drilled, the inclination 140 can maintain, for example, an inclination of about 80 to 90 degrees up to the total depth (TD).

[0065] A recoverable open well whipstock can then be placed in the second well 70 at the branch point of the fourth circuit, i.e., region 70D, and a fourth circuit 100-4 (i.e., in this example, n=4) can be drilled from the second well 70 toward the first well 40, and a guide such as a magnetic ranging tool can be used to guide the fourth circuit 100-4 to connect with the first well 40 in region 40A.

[0066] The open well retrieveable whipstock is retrieved and moved to a third sidecut location, region 70C, and the procedure can be repeated toward the first well 40 at region 40B, then for a second circuit 100-2 between region 70B of the second well 70 and region 40C of the first well 40, and then for the first circuit 100-1 between region 70A of the second well 70 and region 40D of the first well 40. Generally speaking, this process can be repeated for each circuit n, n-1, n-2, n-3, etc., until the first circuit is reached.

[0067] After each circuit 100 is excavated, calculations and / or measurements and / or other determinations can be made to determine the volume within the circuit 100, and string hole openers can be used to open at least a portion of each circuit to match within a selected variance, such as within about 10 percent or less of the volume of the fourth circuit 100-4 (i.e., the first circuit to which completion has been completed).

[0068] After completion and during operation, a working fluid may be circulated through the circuit 100 to carry heat from the subsurface formation 110 to the surface 30. As shown, for example, a relatively cool or cooled working fluid may be circulated downward through the second well 70 and may be relatively hotter or heated through the circuit 100 and circulated upward through the first well 40. However, the direction of circulation in such a loop may be reversed.

[0069] The dimensions shown, for example a TVD of 4500 m and a length of 4500 m in FIG. 3 and 1000 m in FIG. 4, are all merely examples and are intended to illustrate one disclosed embodiment.

[0070] Example 3 5-7 (embodiment ii), a first wellbore 40 can be drilled to the TVD of the formation using a directional drilling tool and landed at about 80-90 degrees. After the first wellbore 40 is cased to this point, i.e., the ICP 50 of the first wellbore, drilling can then continue while holding at about 90 degrees for the length of the first wellbore 40. After TD, a recoverable open well whipstock can be placed at the fourth circuit connection point, i.e., region 40D, and sidecutting, for example, about 100 m or so, is performed to facilitate subsequent connection using magnetic ranging. The whipstock can then be retrieved and moved to the third circuit connection point, i.e., region 40C, and the procedure can be repeated, and then continued to the second circuit connection point, i.e., region 40B, and then to the first circuit connection point, i.e., region 40A.

[0071] The second well 70 can then be drilled at a slightly higher TVD to about 80-90 degrees, with a well separation 130 between the first well 40 and the second well 70 being, for example, about 1000 m. The second well 70 can then be cased up to the ICP 80 of the second well. After the second well 70 is drilled, a dip 140 of about 80-90 degrees can be maintained up to the TD. An open well retrievable whipstock can then be placed at the branch point of the fourth circuit, i.e., in area 70D, and the fourth circuit 100-4 can be drilled towards the first well 40 and connected to area 40A using a magnetic ranging tool. The open well retrieveable whipstock is retrieved and moved to the third circuit sidecut point, i.e., area 70C, and the third circuit 100-3 can be drilled toward the first wellbore 40 and connected to area 40B using a magnetic ranging tool, and this procedure can continue for the second circuit 100-2 extending between areas 70B and 40C, and then for the first circuit 100-1 extending between areas 70A and 40D. After each circuit is drilled, calculations and / or measurements and / or other determinations can be made to determine the volume within the circuit 100, and string hole openers can be used to open portions of each circuit to match within a selected variance, such as within about 10 percent or less of the volume of the fourth circuit 100-4 (i.e., the first circuit completed).

[0072] After completion and during operation, a working fluid may be circulated through the circuit 100 to carry heat from the subsurface formation 110 to the surface 30. As shown, for example, a relatively cool or cooled working fluid may be circulated downward through the second well 70 and may be relatively hotter or heated through the circuit 100 and circulated upward through the first well 40. However, such loop direction may be reversed.

[0073] The dimensions shown, for example, a TVD of 4500 m and a length of 4500 m in FIG. 6 and 1000 m in FIG. 7, are all merely examples and are intended to illustrate one disclosed embodiment.

[0074] Example 4 8-10 (embodiment iii), a first wellbore 40 may be drilled using a directional drilling tool to the TVD of the formation and landed at approximately 80-90 degrees. After the first wellbore 40 is cased to this point, i.e., the ICP of the first wellbore, drilling may then continue for the length of the first wellbore 40, holding at approximately 80-90 degrees.

[0075] The second well 70 can then be drilled to about 80-90 degrees with a slightly higher TVD and a well separation between the first well 40 and the second well 70 of, for example, about 1000 m. The second well 70 can then be cased up to the ICP 80 of the second well.

[0076] After the second well 70 is drilled, the inclination 140 can be maintained at, for example, about 80 to 90 degrees up to the TD.

[0077] A retrieveable open well whipstock can then be placed at the branch point of the fourth circuit, i.e., area 70D, and a fourth circuit 100-4 can be drilled from the second well 70 toward the first well 40 and connected to area 40A using a magnetic ranging tool.

[0078] The open well retrieveable whipstock is retrieved and moved to the third circuit sidecut point, i.e., region 70C, and the third circuit 100-3 can be drilled from the second well 70 toward the first well 40, i.e., region 40B, and this procedure can continue for the second circuit 100-2 between regions 70B and 40C, and for the first circuit 100-1 between regions 70A and 40D. After each circuit is drilled, calculations and / or measurements and / or other determinations can be made to determine the volume within the circuit, and string hole openers can be used to open portions of each circuit to match within a selected variance, such as, for example, less than about 10% of the volume of the fourth circuit 100-4 (i.e., the first circuit that has been completed).

[0079] After completion and during operation, a working fluid may be circulated through the circuit 100 to carry heat from the subsurface formation 110 to the surface 30. As shown, for example, a relatively cool or cooled working fluid may be circulated downward through the second well 70 and passed through the circuit 100 to a relatively high temperature or heated working fluid which may then be circulated upward through the first well 40. However, the direction of circulation in such a loop may be reversed.

[0080] The dimensions shown, e.g., 1000m and 4500m lengths in FIG. 8, 4500m TVD in FIG. 9, and 4500m TVD and 3-4km lengths in FIG. 10, are all merely examples and are intended to illustrate one disclosed embodiment.

[0081] Variations The disclosed systems and methods can be practiced using a wide variety of well configurations and drilling / completion techniques. Examples 5-8 below relate to embodiments 1 and 2, and options A and B. Example 9 relates to embodiment 3.

[0082] In terms of the general design and shape of the wells, 1A, 1B, 2A and 2B can be substantially similar. In both embodiments 1 and 2, the difference between A and B can be, for example, the manner in which the wells are drilled and connected, each of which is an example contemplated within the scope of the present disclosure. However, the first wellbore, the second wellbore, and the multiple open-hole circuits extending between the first and second wellbore holes and forming a substantially sealed closed loop can be drilled and completed according to known wellbore drilling techniques.

[0083] Embodiments 1 and 2 are substantially similar, the difference can be the shape / direction in which the down section is excavated. Embodiment 1 can have a "straight" (plan view) shape with two sections branching off to the left and two sections branching off to the right. Embodiment 2 can have a down section where the main shaft is "curved" (plan view) and then the branched section exits on the right side.

[0084] In option B, the upwell is drilled to TD (full depth) and then the drillstring is pulled back and branched to drill each of the branch shafts (sections marked "A") in sequence (A, B, C, D). The directional guidance tracker can be deployed, for example, on a coiled piping rig. Because the tracker is directional guided, it allows re-entry into the individual shafts with a directional ranging tool, and then when drilling the downwell, the ranging tool can be aimed in each branch to connect them.

[0085] Embodiment 3 can be implemented, for example, when the surface location can be approximately centered relative to the target reservoir of interest. The closed loop system of embodiment 3 uses a curved hook-like middle section to obtain a horizontal or approximately 90 degree incline while drilling.

[0086] Example 5 11-13 (Embodiment 1A), a general schematic diagram illustrates several options for using heat extracted from a geothermal formation in the earth. The recovered thermal energy can be used for a variety of purposes, depending, for example, on one or more of the temperature and / or amount, and / or user needs and / or economics, and / or other factors. The thermal energy of the loop working fluid can be used, for example, for thermal energy processes and / or for heating, such as heating a greenhouse.

[0087] In one disclosed embodiment, the working fluid heated in the loop can be used directly as thermal energy for district heating. For example, the heated working fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to the loop by pipeline 190. In one disclosed embodiment, the working fluid heated in the loop and the district heating fluid are separated from each other, the district heating fluid is heated by the working fluid via heat exchanger 160, and the district heating fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to heat exchanger 160 for reheating by the working fluid. In one disclosed embodiment, the use of the thermal energy can include a thermal process such as an organic Rankine cycle (ORC) system 150. In such an embodiment, if an ORC system 150 or other thermodynamic system is present, the loop working fluid remains separated from the ORC system fluid and does not come into contact / mix with the ORC system fluid. After passing through heat exchanger 160, the working fluid can be used, for example, as described above. In a disclosed embodiment, additional heat exchangers can be used to heat the district heating fluid for district heating, for example, as described above and / or combinations thereof. If an ORC system 150 is not installed, e.g., there is no generation of electricity, only thermal energy / heat use, the loop working fluid can be used directly in the district heating pipeline 180. These are just a few examples shown in connection with the closed loop wellbore systems of the present disclosure, for example, as shown in Figures 1-10.

[0088] In one disclosed embodiment, the thermal energy of the working fluid, the proximity of the user, and other factors may influence the design, for example, in one disclosed embodiment, 120° C. of thermal energy may be more suitable for the thermal energy process.

[0089] In addition, FIG. 11 illustrates that the heat in the high temperature heat transfer loop solution can be provided to the organic Rankine cycle (ORC) system 150 via heat exchanger 160 and pipeline 170 to the ORC system 150. The thermal energy can be used for district heating, such as by delivering the heated fluid via pipeline 180 to the town or nearby users, such as greenhouses, hydroponics, aquaculture, or combinations thereof, for district heating. The fluid from the ORC system 150 can be returned to the heat exchanger 160 for reheating and repeating the process. The ORC system can use the heated fluid to expand gases with a lower boiling point to turn turbines to generate electricity, and excess thermal energy not used by the ORC can then be sent to the town via heated water through pipeline 180 for district heating as described above.

[0090] In the drawings, the ORC system 150 is illustrated in a simplified form. The hot loop working fluid passes through a closed loop system to a heat exchanger 160 to heat a separated fluid (separated from the loop working fluid), which is then sent via a pipeline 170 to the ORC system 150 where the thermal energy in the separated fluid is used. The heat may be used for district heating as described above without generating electricity, or the heat may be used, for example, to expand gas to drive a turbine to generate electricity in the ORC system 150, or for other thermodynamic processes. As an example, the separated fluid may include water. The separated fluid, e.g., water, after being used by the ORC may have some thermal energy remaining, and the fluid, e.g., water, may be sent via a pipeline 180 to nearby heating users, such as to a town for district heating and / or to an industrial or commercial user for process or other heating. The remaining separated water not used by the ORC system 150 or heating can be sent downhole via return downflow line 190 for reheating if the loop working fluid has been used, or can be returned to the heat exchanger 160 for reheating if the separated fluid has been used.

[0091] In one disclosed embodiment, the loop working fluid can be used directly to drive a thermodynamic process, such as the ORC system 150, or the loop working fluid can be fed to a pipeline 180 for district heating as described above. In one disclosed embodiment, the loop working fluid can be used indirectly to heat an intermediate, separated fluid, which can be used to drive a thermodynamic process, such as the ORC system 150, or the separated fluid can be fed to a pipeline 180 for district heating as described above. The thermal energy of the loop working fluid can be used directly and / or indirectly.

[0092] The dimensions shown, for example, 4500m TVD and 4500m length in FIG. 12 and 1000m in FIG. 13, are all merely examples and are intended to illustrate one disclosed embodiment.

[0093] Example 6 14-16 (Embodiment 1B), general schematic diagrams illustrate several options for using heat extracted from a geothermal formation in the earth. The recovered thermal energy can be used for a variety of purposes, depending, for example, on one or more of the temperature and / or amount, and / or user needs and / or economics, and / or other factors. The thermal energy of the loop working fluid can be used, for example, for thermal energy processes and / or for heating, such as heating a greenhouse.

[0094] In one disclosed embodiment, the working fluid heated in the loop can be used directly as thermal energy for district heating. For example, the heated working fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to the loop by pipeline 190. In one disclosed embodiment, the working fluid heated in the loop and the district heating fluid are separated from each other, the district heating fluid is heated by the working fluid via heat exchanger 160, and the district heating fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to heat exchanger 160 for reheating by the working fluid. In one disclosed embodiment, the use of the thermal energy can include a thermal process such as an organic Rankine cycle (ORC) system 150. In such an embodiment, if an ORC system 150 or other thermodynamic system is present, the loop working fluid remains separated from the ORC system fluid and does not come into contact / mix with the ORC system fluid. After passing through heat exchanger 160, the working fluid can be used, for example, as described above. In a disclosed embodiment, additional heat exchangers can be used to heat the district heating fluid for district heating, for example, as described above and / or combinations thereof. If an ORC system 150 is not installed, e.g., there is no generation of electricity, only thermal energy / heat use, the loop working fluid can be used directly in the district heating pipeline 180. These are just a few examples shown in connection with the closed loop wellbore systems of the present disclosure, for example, as shown in Figures 1-10.

[0095] In one disclosed embodiment, the thermal energy of the working fluid, the proximity of the user, and other factors may influence the design, for example, in one disclosed embodiment, 120° C. of thermal energy may be more suitable for the thermal energy process.

[0096] In addition, FIG. 14 illustrates that the heat in the high temperature heat transfer loop solution can be provided to the organic Rankine cycle (ORC) system 150 via heat exchanger 160 and pipeline 170 to the ORC system 150. The thermal energy can be used for district heating, such as by delivering the heated fluid via pipeline 180 to the town or nearby users, such as greenhouses, hydroponics, aquaculture, or combinations thereof, for district heating. The fluid from the ORC system 150 can be returned to the heat exchanger 160 for reheating and repeating the process. The ORC system can use the heated fluid to expand gases with lower boiling points to turn turbines to generate electricity, and excess thermal energy not used by the ORC can then be sent to the town via heated water via pipeline 180 for district heating as described above.

[0097] In the drawings, the ORC system 150 is illustrated in a simplified form. The hot loop working fluid passes through a closed loop system to a heat exchanger 160 to heat a separated fluid (separated from the loop working fluid), which is then sent via a pipeline 170 to the ORC system 150 where the thermal energy in the separated fluid is used. The heat may be used for district heating as described above without generating electricity, or the heat may be used, for example, to expand gas to drive a turbine to generate electricity in the ORC system 150, or for other thermodynamic processes. As an example, the separated fluid may include water. The separated fluid, e.g., water, after being used by the ORC may have some thermal energy remaining, and the fluid, e.g., water, may be sent via a pipeline 180 to nearby heating users, such as to a town for district heating and / or to an industrial or commercial user for process or other heating. The remaining separated water not used by the ORC system 150 or heating can be sent downhole via return downflow line 190 for reheating if the loop working fluid has been used, or can be returned to the heat exchanger 160 for reheating if the separated fluid has been used.

[0098] In one disclosed embodiment, the loop working fluid can be used directly to drive a thermodynamic process, such as the ORC system 150, or the loop working fluid can be fed to a pipeline 180 for district heating as described above. In one disclosed embodiment, the loop working fluid can be used indirectly to heat an intermediate, separated fluid, which can be used to drive a thermodynamic process, such as the ORC system 150, or the separated fluid can be fed to a pipeline 180 for district heating as described above. The thermal energy of the loop working fluid can be used directly and / or indirectly.

[0099] The dimensions shown, for example, 4500m TVD and 4500m length in FIG. 15 and 1000m in FIG. 16, are all merely examples and are intended to illustrate one disclosed embodiment.

[0100] Example 7 17-19 (Embodiment 2A), general schematic diagrams illustrate several options for using heat extracted from a geothermal formation in the earth. The recovered thermal energy can be used for a variety of purposes, depending, for example, on one or more of the temperature and / or amount, and / or user needs and / or economics, and / or other factors. The thermal energy of the loop working fluid can be used, for example, for thermal energy processes and / or for heating, such as heating a greenhouse.

[0101] In one disclosed embodiment, the working fluid heated in the loop can be used directly as thermal energy for district heating. For example, the heated working fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to the loop by pipeline 190. In one disclosed embodiment, the working fluid heated in the loop and the district heating fluid are separated from each other, the district heating fluid is heated by the working fluid via heat exchanger 160, and the district heating fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to heat exchanger 160 for reheating by the working fluid. In one disclosed embodiment, the use of the thermal energy can include a thermal process such as an organic Rankine cycle (ORC) system 150. In such an embodiment, if an ORC system 150 or other thermodynamic system is present, the loop working fluid remains separated from the ORC system fluid and does not come into contact / mix with the ORC system fluid. After passing through heat exchanger 160, the working fluid can be used, for example, as described above. In a disclosed embodiment, additional heat exchangers can be used to heat the district heating fluid for district heating, for example, as described above and / or combinations thereof. If an ORC system 150 is not installed, e.g., there is no generation of electricity, only thermal energy / heat use, the loop working fluid can be used directly in the district heating pipeline 180. These are just a few examples shown in connection with the closed loop wellbore systems of the present disclosure, for example, as shown in Figures 1-10.

[0102] In one disclosed embodiment, the thermal energy of the working fluid, the proximity of the user, and other factors may influence the design, for example, in one disclosed embodiment, 120° C. of thermal energy may be more suitable for the thermal energy process.

[0103] In addition, FIG. 17 illustrates that the heat in the high temperature heat transfer loop solution can be provided to the organic Rankine cycle (ORC) system 150 via heat exchanger 160 and pipeline 170 to the ORC system 150. The thermal energy can be used for district heating, such as by delivering the heated fluid via pipeline 180 to the town or nearby users, such as greenhouses, hydroponics, aquaculture, or combinations thereof, for district heating. The fluid from the ORC system 150 can be returned to the heat exchanger 160 for reheating and repeating the process. The ORC system can use the heated fluid to expand gases with a lower boiling point to turn turbines to generate electricity, and excess thermal energy not used by the ORC can then be sent to the town via heated water via pipeline 180 for district heating as described above.

[0104] In the drawings, the ORC system 150 is illustrated in a simplified form. The hot loop working fluid passes through a closed loop system to a heat exchanger 160 to heat a separated fluid (separated from the loop working fluid), which is then sent via a pipeline 170 to the ORC system 150 where the thermal energy in the separated fluid is used. The heat may be used for district heating as described above without generating electricity, or the heat may be used, for example, to expand gas to drive a turbine to generate electricity in the ORC system 150, or for other thermodynamic processes. As an example, the separated fluid may include water. The separated fluid, e.g., water, after being used by the ORC may have some thermal energy remaining, and the fluid, e.g., water, may be sent via a pipeline 180 to nearby heating users, such as to a town for district heating and / or to an industrial or commercial user for process or other heating. The remaining separated water not used by the ORC system 150 or heating can be sent downhole via return downflow line 190 for reheating if the loop working fluid has been used, or can be returned to the heat exchanger 160 for reheating if the separated fluid has been used.

[0105] In one disclosed embodiment, the loop working fluid can be used directly to drive a thermodynamic process, such as the ORC system 150, or the loop working fluid can be fed to a pipeline 180 for district heating as described above. In one disclosed embodiment, the loop working fluid can be used indirectly to heat an intermediate, separated fluid, which can be used to drive a thermodynamic process, such as the ORC system 150, or the separated fluid can be fed to a pipeline 180 for district heating as described above. The thermal energy of the loop working fluid can be used directly and / or indirectly.

[0106] The dimensions shown, for example 4500m and 1000m in FIG. 17, 4500m in FIG. 18, and 4500m in FIG. 19, are all merely examples and are intended to illustrate one embodiment disclosed.

[0107] Example 8 20-22 (Embodiment 2B), general schematic diagrams illustrate several options for using heat extracted from a geothermal formation in the earth. The recovered thermal energy can be used for a variety of purposes, depending, for example, on one or more of the temperature and / or amount, and / or user needs and / or economics, and / or other factors. The thermal energy of the loop working fluid can be used, for example, for thermal energy processes and / or for heating, such as heating a greenhouse.

[0108] In one disclosed embodiment, the working fluid heated in the loop can be used directly as thermal energy for district heating. For example, the heated working fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to the loop by pipeline 190. In one disclosed embodiment, the working fluid heated in the loop and the district heating fluid are separated from each other, the district heating fluid is heated by the working fluid via heat exchanger 160, and the district heating fluid is transported by pipeline 180 to / from a user such as a town or greenhouse, and then returned to heat exchanger 160 for reheating by the working fluid. In one disclosed embodiment, the use of the thermal energy can include a thermal process such as an organic Rankine cycle (ORC) system 150. In such an embodiment, if an ORC system 150 or other thermodynamic system is present, the loop working fluid remains separated from the ORC system fluid and does not come into contact / mix with the ORC system fluid. After passing through heat exchanger 160, the working fluid can be used, for example, as described above. In a disclosed embodiment, additional heat exchangers can be used to heat the district heating fluid for district heating, for example, as described above and / or combinations thereof. If an ORC system 150 is not installed, e.g., there is no generation of electricity, only thermal energy / heat use, the loop working fluid can be used directly in the district heating pipeline 180. These are just a few examples shown in connection with the closed loop wellbore systems of the present disclosure, for example, as shown in Figures 1-10.

[0109] In one disclosed embodiment, the thermal energy of the working fluid, the proximity of the user, and other factors may influence the design, for example, in one disclosed embodiment, 120° C. of thermal energy may be more suitable for the thermal energy process.

[0110] In addition, FIG. 20 illustrates that the heat in the high temperature heat transfer loop solution can be provided to the organic Rankine cycle (ORC) system 150 via heat exchanger 160 and pipeline 170 to the ORC system 150. The thermal energy can be used for district heating, such as by delivering the heated fluid via pipeline 180 to the town or nearby users, such as greenhouses, hydroponics, aquaculture, or combinations thereof, for district heating. The fluid from the ORC system 150 can be returned to the heat exchanger 160 for reheating and repeating the process. The ORC system can use the heated fluid to expand gases with a lower boiling point to turn turbines to generate electricity, and excess thermal energy not used by the ORC can then be sent to the town via heated water through pipeline 180 for district heating as described above.

[0111] In the drawings, the ORC system 150 is illustrated in a simplified form. The hot loop working fluid passes through a closed loop system to a heat exchanger 160 to heat a separated fluid (separated from the loop working fluid), which is then sent via a pipeline 170 to the ORC system 150 where the thermal energy in the separated fluid is used. The heat may be used for district heating as described above without generating electricity, or the heat may be used, for example, to expand gas to drive a turbine to generate electricity in the ORC system 150, or for other thermodynamic processes. As an example, the separated fluid may include water. The separated fluid, e.g., water, after being used by the ORC may have some thermal energy remaining, and the fluid, e.g., water, may be sent via a pipeline 180 to nearby heating users, such as to a town for district heating and / or to an industrial or commercial user for process or other heating. The remaining separated water not used by the ORC system 150 or heating can be sent downhole via return downflow line 190 for reheating if the loop working fluid has been used, or can be returned to the heat exchanger 160 for reheating if the separated fluid has been used.

[0112] In one disclosed embodiment, the loop working fluid can be used directly to drive a thermodynamic process, such as the ORC system 150, or the loop working fluid can be fed to a pipeline 180 for district heating as described above. In one disclosed embodiment, the loop working fluid can be used indirectly to heat an intermediate, separated fluid, which can be used to drive a thermodynamic process, such as the ORC system 150, or the separated fluid can be fed to a pipeline 180 for district heating as described above. The thermal energy of the loop working fluid can be used directly and / or indirectly.

[0113] The dimensions shown, for example 4500m and 1000m in FIG. 20, 4500m in FIG. 21, and 4500m in FIG. 22, are all merely examples and are intended to illustrate one embodiment disclosed.

[0114] Example 9 23-26 (Embodiment 3), a first wellbore 40 can be drilled from the well site 20 using a directional drilling tool like a curved hook to the TVD of the formation and landed at approximately 90 degrees. The first wellbore 40 can be cased to this point, the ICP 50 of the first well.

[0115] After casing, the first well 40 can be drilled while held at about 90 degrees, and a retrievable open well whipstock can be placed at the fourth circuit connection point, region 40D, and side drilling can be performed, for example, about 100-500 m to facilitate connection using magnetic ranging. The whipstock can then be retrieved and moved to the third circuit connection point, region 40C, and the procedure can be repeated, and then continued to the second circuit connection point, region 40B, and then to the first circuit connection point, region 40A.

[0116] The second well 70 can then be drilled substantially parallel to the first well 40 and in the opposite direction, for example, in a similar curved hook shape to about 90 degrees with a well separation 130 between the first well 40 and the second well 70 of about 4500 m. The second well 70 can then be cased to its ICP, i.e., the ICP 80 of the second well. After the second well 70 is drilled, the about 90 degree inclination 140 can be maintained to TD. A surface well retrievable whipstock can then be placed at the branch point of the fourth circuit, i.e., in area 70D, and the fourth circuit 100-4 can be drilled towards the first well 40 and connected to area 40A using a magnetic ranging tool. Again, as mentioned above, the use of n=4 is merely an example, and the number of circuits 100 in the present disclosure is n, so this would start from the nth circuit. For example, if the number of circuits 100 were eleven, one would start with the eleventh circuit rather than the fourth. Continuing with this n=4 example, the retrieveable openhole whipstock could be retrieved and moved to the branch point of the third circuit, i.e., area 70C, and the procedure could continue for the third circuit 100-3, the second circuit 100-2, and then the first circuit 100-1. After each circuit is excavated, calculations and / or measurements and / or other determinations could be made to determine the volume within the circuit 100, and string hole openers would be used to open portions of each circuit to match within a selected variance, such as within about ten percent or less of the volume of the fourth circuit 100-4 (i.e., the first circuit to be completed).

[0117] In order to change direction, a certain distance / length of wellbore may be required to change direction while drilling. In one disclosed embodiment, the trajectory of the first well and / or the second well may follow a curved hook-like trajectory, in which the well is drilled from the well site away from the geothermal source target area of ​​the formation for a certain distance and / or depth, and then passes back through the target area. In one disclosed embodiment, both the first well and the second well follow a curved hook-like trajectory, e.g., as shown in FIG. 25. This may be used, for example, when the well site is approximately centered above the geothermal source target area, e.g., to increase the capacity for the number of circuits that may be drilled and / or the contact area / volume between the circuits and the geothermal source. In one disclosed embodiment, for example, using a curved hook-like trajectory may allow more circuits to be drilled compared to a vertical to lateral trajectory. In one disclosed embodiment, for example, the use of curved hook-shaped tracks may enable 8-10 or more circuits.

[0118] Any dimensions shown, for example 4500m and 4500m in FIG. 24, are merely examples and are intended to illustrate one embodiment disclosed.

[0119] Additional Embodiments In some aspects, the present disclosure relates to geothermal systems and related methods according to, among other embodiments, the following:

[0120] Embodiment 1. A system includes: a) a first wellbore extending from the earth's surface to a geothermal formation in the earth, the first wellbore including a lateral section within the formation; b) a second wellbore extending from the earth's surface to a geothermal formation in the earth, the second wellbore including a lateral section within the formation in the earth; and c) a plurality of open-hole circuits extending between the lateral section of the first wellbore and the lateral section of the second wellbore, wherein the first wellbore, the second wellbore, and the plurality of circuits form a substantially sealed closed loop, and the plurality of circuits are balanced.

[0121] Embodiment 2. The system of embodiment 1, wherein the plurality of circuits comprises one or more of: a) substantially equal circuit velocities, b) substantially equal circuit pressure drops, c) substantially equal circuit lengths, d) substantially equal circuit volumes, e) substantially equal resistances, ΔP / flow rates, and f) combinations thereof.

[0122] Embodiment 3. The system of embodiment 1 or 2, wherein circuit parameters of the plurality of circuits are substantially consistent.

[0123] Embodiment 4. The system of embodiment 3, wherein the circuit parameters include one or more of: a) fluid velocity in the circuit, b) pressure drop in the circuit, c) length of the circuit, d) volume of the circuit, e) resistance, ΔP / flow, and f) combinations thereof.

[0124] Embodiment 5. The system of embodiment 3 or 4, wherein the circuit parameters include a fluid velocity in the circuit, and a length of the circuit.

[0125] Embodiment 6. The system of any one of embodiments 1-5, wherein a plurality of open-hole circuits connect the first wellbore and the second wellbore in a first-out / last-in configuration, and flow throughout the plurality of open-hole circuits is balanced.

[0126] Embodiment 7. The system of any one of embodiments 1-6, further comprising a heat exchange adapted to extract thermal energy from the working fluid circulated through the plurality of open-hole circuits.

[0127] Embodiment 8. A method comprising: providing a first wellbore extending from the earth's surface to a geothermal formation in the earth, the first wellbore including a lateral section in the formation; providing a second wellbore extending from the earth's surface to a geothermal formation in the earth, the second wellbore including a lateral section in the formation in the earth; providing a plurality of open-hole circuits extending between the lateral section of the first wellbore and the lateral section of the second wellbore; wherein the first wellbore, the second wellbore and the plurality of circuits form a substantially closed loop, the plurality of circuits being balanced, and circulating a working fluid through the substantially closed loop to transport thermal energy from the geothermal formation in the earth to the surface.

[0128] Embodiment 9. The method of embodiment 8, wherein the plurality of circuits comprises one or more of: a) substantially equal circuit fluid velocities, b) substantially equal circuit pressure drops, c) substantially equal circuit lengths, d) substantially equal circuit volumes, e) substantially equal resistances, ΔP / flow rates, and f) combinations thereof.

[0129]

[0023] Embodiment 10. The method of embodiment 8 or 9, further comprising: calculating circuit parameters of a first circuit of the plurality of circuits; and adapting remaining circuits of the plurality of circuits, respectively, to substantially match the circuit parameters.

[0130] Embodiment 11. The method of embodiment 10, wherein the circuit parameters include one or more of: a) fluid velocity in the circuit, b) pressure drop in the circuit, c) volume of the circuit, d) length of the circuit, e) resistance of the circuit, ΔP / flow rate, and f) combinations thereof.

[0131]

[0023] Embodiment 12. The method of embodiment 8 or 9, further comprising: calculating circuit parameters of a first circuit of the plurality of circuits; and modifying remaining circuits of the plurality of circuits, respectively, to substantially match the circuit parameters.

[0132] Embodiment 13. The method of embodiment 12, wherein the circuit parameters include one or more of: a) fluid velocity in the circuit, b) pressure drop in the circuit, c) length of the circuit, d) volume of the circuit, e) resistance of the circuit, ΔP / flow, and f) combinations thereof.

[0133]

[0023] Embodiment 14. The method of embodiment 12 or 13, wherein modifying each remaining circuit of the plurality of circuits comprises enlarging at least a portion of at least one of the plurality of circuits.

[0134] Embodiment 15. The method of any one of embodiments 8 to 14, wherein the working fluid is circulated at least in part by thermosiphoning.

[0135]

[0031] Embodiment 16. The method of any one of embodiments 8-15, further comprising using at least a portion of the thermal energy to provide heating to a user.

[0136] Embodiment 17. The method of any one of embodiments 8-16, further comprising using at least a portion of the thermal energy to generate electricity.

[0137] Embodiment 18. The method of embodiment 11 or 13, wherein the circuit parameters include fluid velocity in the circuit, and length of the circuit.

[0138]

[0031] Embodiment 19. The method of any one of embodiments 8-18, further comprising connecting the first wellbore and the second wellbore in a first-out / last-in configuration with a plurality of open-hole circuits.

[0139] Embodiment 20. The method of any one of embodiments 8-19, wherein flow throughout the multiple open-hole circuits is balanced.

[0140] In one disclosed embodiment, the circuits connecting the supply and return vertical headers can all be of substantially equal length, substantially equal variable diameter, substantially equal resistance, and configured in a "first-in supply well - last-in return well" configuration that enforces substantially equal fluid flow rates through all circuits, whether there are 2, 10, or any number n of circuits connected as described herein. In one disclosed embodiment, the above features can be combined with any one of embodiments 1-20.

[0141] In one disclosed embodiment, a substantially equal flow rate of the working fluid can be provided throughout all circuits between the supply vertical header and the return vertical header. In one disclosed embodiment, the feature can be combined with any one of the first to twentieth embodiments.

[0142] In one disclosed embodiment, a Reynolds number of 2500 or greater can provide improved or optimal heat transfer when the relevant conditions in each circuit are substantially equal, e.g., within about + / - 15 percent, or within about + / - 10 percent. In one disclosed embodiment, the feature can be combined with any one of embodiments 1-20.

[0143] In one disclosed embodiment, enough information about each circuit needs to be known to accurately predict the flow rate required to optimize the transfer of heat across all circuits, and to calculate the necessary information from the circuits (as built) (best practices). In one disclosed embodiment, the feature can be combined with any one of the embodiments 1-20.

[0144] Knowing that all circuits have equal volumes and flow rates through them may allow accurate modeling of the formation's heat transfer coefficient. Similarly, by using string hole openers to change the wellbore diameter, the Reynolds number (a dimensionless number) can be increased, and therefore the heat transfer coefficient can also be increased. In one disclosed embodiment, the above feature can be combined with any one of the embodiments 1-20.

[0145] Increasing the geological contact area may allow for more efficient production of thermal energy.

[0146] In one disclosed embodiment, drilling from the same location (well site) can make the project scalable, allowing contact with the formation in all compass directions, rather than being limited to north-south or east-west. With a single location, capital expenditures (CAPEX) can also be significantly reduced by requiring only a single facility at the well site and no temporary infrastructure. For example, from a well site, multiple closed-loop well systems as described herein can be provided that extend outward from the well site in multiple directions, to multiple depths, to multiple lengths, and / or combinations thereof. In one disclosed embodiment, the features can be combined with any one of embodiments 1-20.

[0147] The disclosed balanced loop can be designed to target dry, narrow zone thermal formations. In one disclosed embodiment, the above features can be combined with any one of the embodiments 1 to 20.

[0148] The design can optimize the amount of heat that can be extracted from the formation to improve the economics of geothermal energy from low to medium enthalpy formations. In one disclosed embodiment, the above features can be combined with any one of the first to twenty embodiments.

[0149] The terms "heat transfer fluid" or "heat transfer solution" are used broadly and interchangeably herein to refer to any fluid that may be conveyed through the loop to transfer heat from the geothermal formation to the surface. Examples include water, water / glycol, and supercritical CO 2 Includes, but is not limited to:

[0150] The terms "circuit" or "leg" or "lateral" are used broadly and interchangeably herein to refer to any open-hole conduit that extends at least partially through a geothermal formation between a first well and a second well, between the circuits, or both.

[0151] The term "resistance" or "circuit resistance" is used broadly herein to refer to the change in pressure divided by flow rate: ΔP / flow rate.

[0152] In one disclosed embodiment, the second well can be used as a supply well and the first well can be used as a return well. The supply well can also be referred to as a "cold" well and the return well can also be referred to as a "hot" well. In such an embodiment, with reference to the drawings, the second well is "cold" and the first well is "hot". In one disclosed embodiment, the first well can be used as a supply well and the second well can be used as a return well. In one disclosed embodiment, the features can be combined with any one of the embodiments 1 to 20.

[0153] In one disclosed embodiment, the first well and / or the second well can be substantially vertical at the earth's surface, with a vertical section extending substantially vertically to a depth that may vary between the first and second wells, and then redirecting to a substantially horizontal or inclined section. The redirection can use techniques known to those skilled in the art, including, but not limited to, using directional drilling to construct a lateral section extending from the vertical section, or a vertical section followed by a horizontal or inclined section, from vertical to horizontal. At least a portion of the multiple circuits can be substantially horizontal through at least a portion of the geothermal formation in the earth.

[0154] In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details are not required. In other instances, well-known structures and processes are shown in block diagram form in order not to obscure the understanding.

[0155] The present disclosure provides a system and method for geothermal heat generation. The balanced geothermal energy transfer loop can include a first wellbore and a second wellbore extending from the earth's surface to a geothermal formation in the earth, and a plurality of balanced open-hole circuits extending through the geothermal formation between the first wellbore and the second wellbore, forming a substantially sealed closed loop. Each of the plurality of circuits can be designed or modified to have substantially equal circuit parameters. The circuit parameters can include one or more of a circuit fluid velocity, a circuit pressure drop, a circuit volume, and / or a circuit length. The circuit parameters can include a circuit length and volume, and the circuit connects the supply / return wells in a first-out / last-in configuration.

[0156] The above embodiments are intended to be merely examples. Changes, modifications, and variations may be made to the specific embodiments by those skilled in the art. The claims are not to be limited by the specific embodiments set forth herein, but are to be interpreted in a manner consistent with the present specification as a whole.

Claims

1. 1. A system comprising: a. a first wellbore extending from the earth's surface to a geothermal formation within the earth, the first wellbore including a lateral section within the formation; b. a second wellbore extending from the surface of the earth to a geothermal formation within the earth, the second wellbore including a lateral section within the geothermal formation within the earth; c. a plurality of open-hole circuits extending between the lateral section of the first wellbore and the lateral section of the second wellbore; Including, the first wellbore, the second wellbore, and the plurality of circuits form a substantially closed loop; The system wherein the plurality of circuits are balanced.

2. The plurality of circuits include a. Substantially equal circuit speeds; b. Substantially equal circuit pressure drops; c. Substantially equal circuit lengths; d. Substantially equal circuit volumes; e. Substantially equal resistance, ΔP / flow, and f. Combinations thereof; The system of claim 1 , comprising one or more of:

3. The system of claim 1 or 2, wherein circuit parameters of the plurality of circuits are substantially consistent.

4. The circuit parameters are a. The fluid velocity in the circuit; b. Pressure drop in the circuit; c. The length of the circuit; d. Volume of the circuit; e. Resistance, ΔP / Flow, and f. Combinations thereof; The system of claim 3 , comprising one or more of:

5. The system of claim 4 , wherein the circuit parameters include a fluid velocity in the circuit and a length of the circuit.

6. 6. The system of claim 1, wherein the plurality of open-hole circuits connect the first wellbore and the second wellbore in a first-out / last-in configuration and flow throughout the plurality of open-hole circuits is balanced.

7. The system of any one of claims 1 to 6, further comprising a heat exchange adapted to extract thermal energy from a working fluid circulated through the plurality of open well circuits.

8. 1. A method comprising: providing a first wellbore extending from the earth's surface to a geothermal formation within the earth, the first wellbore including a lateral section within the formation; providing a second wellbore extending from the surface of the earth to a geothermal formation within the earth, the second wellbore including a lateral section within the geothermal formation; providing a plurality of open well circuits extending between the lateral section of the first wellbore and the lateral section of the second wellbore; Including, the first wellbore, the second wellbore, and the plurality of circuits form a substantially closed loop; The method wherein the plurality of circuits are balanced and a working fluid is circulated through the substantially closed loop to transport thermal energy from the geothermal formation within the earth to the surface.

9. The plurality of circuits include a. Substantially equal circuit fluid velocities; b. Substantially equal circuit pressure drops; c. Substantially equal circuit lengths; d. Substantially equal circuit volumes; e. Substantially equal resistance, ΔP / flow, and f. Combinations thereof; The method of claim 8, comprising one or more of:

10. 10. The method of claim 8 or 9, further comprising: calculating circuit parameters of a first circuit of the plurality of circuits; and adapting each of the remaining circuits of the plurality of circuits to substantially match the circuit parameters.

11. The circuit parameters are a. The fluid velocity in the circuit; b. Pressure drop in the circuit; c. Volume of the circuit; d. Length of the circuit; e. Resistance of the circuit, ΔP / flow rate, and f. Combinations thereof; The method of claim 10, comprising one or more of:

12. 10. The method of claim 8 or 9, further comprising: calculating circuit parameters of a first circuit of the plurality of circuits; and modifying each of the remaining circuits of the plurality of circuits to substantially match the circuit parameters.

13. The circuit parameters are a. The fluid velocity in the circuit; b. Pressure drop in the circuit; c. The length of the circuit; d. Volume of the circuit; e. Resistance of the circuit, ΔP / flow rate, and f. Combinations thereof; The method of claim 12, comprising one or more of:

14. 14. The method of claim 12 or 13, wherein modifying each of the remaining circuits of the plurality of circuits comprises enlarging at least a portion of at least one of the plurality of circuits.

15. A method according to any one of claims 8 to 14, wherein the working fluid is at least partly circulated by thermosiphoning.

16. The method of any one of claims 8 to 15, further comprising using at least a portion of the thermal energy to provide heating to a user.

17. The method of any one of claims 8 to 16, further comprising using at least a portion of the thermal energy to generate electricity.

18. The method of claim 11 or 13, wherein the circuit parameters include fluid velocity in the circuit and length of the circuit.

19. 19. The method of any one of claims 8 to 18, further comprising connecting the first wellbore and the second wellbore with the plurality of openhole circuits in a first-out / last-in configuration.

20. 20. The method of claim 19, wherein flow throughout the plurality of open well circuits is balanced.

Images