A well for extracting heat from the magma body

Abstract

A well bore for extracting heat from magma, and a corresponding method, comprising drilling a borehole from the earth's surface toward a magma chamber, supplying a drilling fluid to an interface between a drill bit and an end of the borehole during drilling, terminating the drilling step in response to the borehole achieving a predetermined depth, and supplying a thermodynamic fluid into the borehole to maintain the borehole during completion of a well, the drilling fluid lifting cuttings out of the borehole, and the drilling fluid quenching the magma to form a solid phase material that can be cut through by the drill bit.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 105,674, filed February 3, 2023, which claims priority to U.S. Provisional Application No. 63 / 337,129, filed May 1, 2022, which is incorporated by reference in its entirety.

[0002] Aspects of the invention relate to geothermal power generation systems and related methods, and more particularly to wells that extract heat from a body of magma. [Background technology]

[0003] Solar, wind, and hydroelectric power are the most commonly available renewable energy sources, but they are notoriously unreliable and have relatively poor power density. In contrast, geothermal energy has the potential to provide high power density and can operate regardless of weather conditions or time of day. However, the lack of necessary technological advances makes geothermal energy an impractical alternative. Summary of the Invention [Means for solving the problem]

[0004] An aspect of the present invention is directed to a well for extracting heat from magma. The well includes a borehole having an opening at the surface and a terminal at a predetermined depth within a magma chamber, a casing disposed within the borehole and extending from the surface to at least an upper end of the magma chamber, a well head connected to the casing at the surface, and a fluid conduit passing through the well head. The fluid conduit supplies a working fluid to the terminal of the well.

[0005] Aspects of the invention are also directed to a method for completing a well for extracting heat from magma, the method including the steps of drilling a borehole from the earth's surface toward a magma chamber, supplying a drilling fluid to an interface between a drill bit and an end of the borehole during drilling, terminating the drilling step in response to the borehole achieving a predetermined depth, and supplying a thermodynamic fluid into the borehole to maintain the borehole during completion of the well, the drilling fluid lifting cuttings out of the borehole, the drilling fluid quenching the magma to form a solid phase material that can be cut through by the drill bit.

[0006] Other aspects, embodiments, and features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings, in which each identical or substantially similar component illustrated in various figures is represented by a single numeral or designation. For clarity, not every component is labeled in every figure. Also, not every component of each embodiment of the invention shown will be labeled unless an explanation is necessary for one of ordinary skill in the art to understand the invention.

[0007] The features of the invention are set forth in the appended claims, but the invention itself, together with its preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of the Earth's mantle illustrating various subterranean magma bodies that may be drilled to harness geothermal energy, in accordance with various illustrative embodiments; [Figure 2A] 1 is a cross-sectional view illustrating a drilling step into a magma body in accordance with an illustrative embodiment; [Figure 2B] 1 is a cross-sectional view illustrating a drilling step into a magma body in accordance with an illustrative embodiment; [Figure 2C] 1 is a cross-sectional view illustrating a drilling step into a magma body in accordance with an illustrative embodiment; [Figure 2D] 1 is a cross-sectional view illustrating a drilling step into a magma body in accordance with an illustrative embodiment; [Diagram 3] 1 is a simplified cross-sectional view of an uncapped well being drilled into a body of magma in accordance with an illustrative embodiment; [Figure 4A] FIG. 1 is a cross-sectional view of a partially cased well in accordance with an illustrative embodiment; [Figure 4B] FIG. 1 is a cross-sectional view of a partially cased well in accordance with an illustrative embodiment; [Figure 4C] FIG. 1 is a cross-sectional view of a partially cased well in accordance with an illustrative embodiment; [Diagram 5] FIG. 1 is a simplified cross-sectional view of a borehole drilled into a magma body 100 in accordance with an illustrative embodiment. [Figure 6A] FIG. 1 is a simplified cross-sectional view of a well casing in accordance with an illustrative embodiment. [Figure 6B] FIG. 11 is a more detailed view of a casing weld in accordance with an exemplary embodiment; [Figure 7A] FIG. 1 is an illustration of a well head that may be used to cap a well in accordance with an illustrative embodiment. [Figure 7B] FIG. 1 is an illustration of a well head that may be used to cap a well in accordance with an illustrative embodiment. [Figure 7C] FIG. 1 is an illustration of a well head that may be used to cap a well in accordance with an illustrative embodiment. [Figure 8] 1 is a simplified cross-sectional view of a partially cased wellbore producing saturated steam from a working fluid according to an illustrative embodiment; [Figure 9] 1 is a simplified cross-sectional view of a cased well for producing saturated steam from a working fluid in accordance with an illustrative embodiment; [Figure 10] 1 is a simplified diagram of a system for producing renewable energy from working fluid injected into any well of the present invention, according to an exemplary embodiment. [Figure 11] 1 is an illustration of a cross-sectional view of a partially cased geothermal well having multiple branches extending into magma in accordance with an illustrative embodiment; [Figure 12] 1 illustrates multiple geothermal wells drilled into the same magma body 100, in accordance with an illustrative embodiment. [Figure 13] 1 illustrates a geothermal well having a borehole drilled horizontally through a rock formation into a body of magma in accordance with an illustrative embodiment; [Figure 14] 1 is an illustration of a flowchart of a process for completing a well in accordance with an illustrative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Traditional renewable energy systems, such as solar, hydroelectric, and wind power, are generally inefficient and not practical as replacements for traditional fossil fuels. Furthermore, the production of energy from these renewable resources is unpredictable. Geothermal energy has shown some early promise. However, most traditional geothermal systems utilize low-temperature resources, such as low-temperature geothermal waters that have temperatures below 194°F. Low-temperature geothermal waters produce low power output. The inability to efficiently and reliably access high-temperature geothermal resources makes traditional geothermal systems economically impractical. These existing geothermal energy systems also produce undesirable pollutants and greenhouse gases.

[0010] Although magma is abundant, making up a large portion of the Earth's mass, and can serve as an ample source of geothermal energy, conventional systems and methods for harnessing renewable energy from geothermal resources are unsuitable for harnessing renewable energy from magma due to its high heat. For example, boreholes drilled into a body of magma are extremely difficult to form and maintain due to the high heat that can cause the borehole to collapse. Additionally, magma can cause excessive wear and fatigue and fouling of drilling equipment.

[0011] The present invention recognizes the need for a geothermal power generation system that utilizes geothermal resources that have sufficiently high temperatures to provide high temperature, high pressure gas phase fluids, which avoids the problems associated with conventional wells that must contend with low permeability.

[0012] Some benefits and improvements provided by the present invention can be made based on the following unexpected observations: the magma can be relatively shallow, at a depth of about 2.1-2.5 km; the upper layer of the magma has few crystals without mush zones; the rock is not ductile and can support fractures; there is no decline in thermal output over a two year period; eruptions at the drilling site are unlikely (e.g., no eruptions have occurred at drilling sites in Africa and Iceland, and no eruptions are believed to have occurred at drilling site Kilauea, Hawaii, in over 10,000 years); drilling into the magma is reasonably safe, and the rising magma can be quenched with water to form a rock plug.

[0013] The present invention describes a system and method for drilling a borehole through rock and into a body of magma, and then maintaining the borehole after creation. The method includes the use of a selected thermodynamic fluid, such as a drilling fluid or working fluid, that has sufficient thermodynamic properties to maintain the integrity and dimensional properties of the well while the geothermal well is drilled and completed. In particular, the thermodynamic fluid should have thermodynamic properties and thermal mass such that the latent heat of crystallization of the magma can be transferred to the thermodynamic fluid. In this way, the thermodynamic fluid can be used as a drilling fluid to quench the magma, thereby allowing the drill bit to drill into the magma. The same or a different thermodynamic fluid can then be used to maintain the well, for example, by preventing or limiting remelting of the solidified magma in the drilled area.

[0014] Figure 1 is a cross-sectional view of the Earth's mantle illustrating various subsurface magma bodies that may be drilled to harness geothermal energy, according to various illustrative embodiments. Non-limiting examples of magma bodies that may provide geothermal energy are shown in Figure 1. These magma bodies may include cones 102, sills 104, dykes 106, plutons 108, laccoliths 110, lapolis 112, and / or diapirs 114.

[0015] In various embodiments disclosed herein, geothermal energy is harnessed by geothermal wells, i.e., wells that include a borehole extending from the Earth's surface into one or more magma bodies 102-114, and equipment for maintaining the borehole and extracting fluids for power generation. Thus, a geothermal well may include casing, fluid conduits, insulation, well heads, etc. The terms "well" or "magma well" may be used interchangeably with "geothermal well." Exemplary geothermal wells are depicted in Figures 3, 4A, 5, 8, 9, and 11. These wells may be capped with a well head, such as well head 700 in Figures 7A-C, and may have an optional casing that extends at least partially the length of the borehole, such as casing 209 in Figures 2A-2D and 4A. The wells may be part of a system depicted in Figure 10 for generating renewable energy from a working fluid injected into the well. The high level steps for drilling into a magma body to complete a renewable energy power generation system are generally shown in Figures 2A-2D.

[0016] 2A-2D are various cross-sectional views illustrating the steps of drilling into a magma body according to an example embodiment. In particular, FIG. 2A is a simplified cross-sectional view depicting the drilling of a borehole 202 by advancing a drilling bit 204 from a surface 205, through rock formations 206, and into the magma body 100. Borehole 202 is depicted as a partially cased borehole including a casing 209, but may be an open borehole as depicted in FIG. 3, or a fully cased borehole as depicted in FIG. 9.

[0017] The drill bit 204 may be coupled to the end of a drilling stem 208, which in some embodiments may also carry drilling fluid 210, represented by arrows, to the end of the borehole 202. The drilling fluid 210 cools the drill bit 204 and lifts the cut out of the borehole 202. As the drill bit 204 approaches the magma body 100, the drilling fluid 210 causes the magma to rapidly release its latent heat of crystallization into the drilling fluid 210, which causes the magma to crystallize or solidify ahead of the drill bit 204, thereby allowing the drill bit 204 to continue cutting the borehole 202 through the magma body 100 until the borehole 202 reaches a desired depth. In this manner, the borehole 202 may be drilled into the magma body 100 without exposing the drill bit 204 to the potentially destructive environment of liquid magma.

[0018] The drilling fluid 210 can stabilize the borehole 202 and control the expansion of the formation into the borehole 202. The drilling fluid 210 can also hydraulically transmit horsepower, which can facilitate motoring of the wellbore. Motoring of the wellbore can be used for directional drilling of the borehole, as depicted in wells 1100 and 1300 of Figures 11 and 13, respectively. The hydraulic pressure also reduces the impact of drilling on pockets of pressurized gas that may expand into the borehole 202.

[0019] Drilling into the magma body 100 requires a drilling fluid 210 that can adequately conduct the latent heat of the magma to maintain it in a crystalline state. Latent heat is energy that is supplied to or extracted from a material to change the phase of the material, i.e., from a liquid to a solid state. The heat content of the magma, including the latent heat component and the sensible heat component, i.e., the heat that can be sensed or measured, is a thermodynamic quantity that is based at least in part on mass, pressure, volatile content, and mineral composition. Thus, the heat content of the magma can vary. The drilling fluid 210 has properties (e.g., mass, thermal conductivity, and viscosity) that facilitate the extraction of a sufficient amount of heat by conduction. The composition and crystallization pressure of the magma, as well as the thermal and rheological kinetics, can be described by the solidification front and Bowen's reaction series, but for illustrative purposes the following generalizations can be made: The latent heat of crystallization of an average silicate magma is about 270 Joules per gram, the heat capacity is about 1.24 J / g·°C, and the average density is about 2.5 g / cm 3 Using these exemplary properties of magma, the total heat released by magma cooling from a starting temperature of 850° C. to 300° C. is 960 J / g. The drilling fluid 210 can accommodate this heat transfer to maintain the integrity of the borehole 202 during drilling.

[0020] Examples of drilling fluid 210 can include water and brine. Additionally, drilling fluid 210 can be a water-based mud, an oil-based mud, or a gas drilling fluid, i.e., drilling fluid 210 can be formed from a base liquid that is oil, water, or brine. The base liquid can be formed from 80-90% of the weight percent of the drilling fluid. Also, drilling fluid 210 can include additives that can aid in drilling but are problematic for use in power generation. The additives can be active solids or inert solids. Active solids can include clays and polymers to create colloidal suspensions that increase the viscosity of the drilling fluid. Inert solids are added to the drilling fluid by cuttings from the drilling operation or by the addition of solids such as barite. Inert solids add density to the drilling fluid without affecting the viscosity of the drilling fluid.

[0021] A sufficient amount of drilling fluid 210 should be provided during drilling so that the drilling fluid does not undergo a liquid to gas phase transition at the interface between the drill bit 204 and the crystallized magma. A liquid phase of the drilling fluid is preferred so that the drilling fluid can continue to efficiently remove latent heat from the crystallized magma by conduction. In some cases, the drilling fluid 210 may be water in a gas or liquid state provided at a rate high enough to maintain a crystallized borehole 202. In other cases, the drilling fluid 210 may be mud.

[0022] The depth of the borehole 202 may be determined by its length. In another embodiment, the depth of the borehole 202 may be determined by the amount of heat provided by the borehole 202. For example, the heat provided by the borehole 202 should be high enough to heat the working fluid 212, represented by the arrows in FIG. 2B, to a temperature sufficient to cause a phase change from a liquid phase to a gas phase, but also allow the working fluid 212 to maintain a high enough temperature and pressure so that it can rise up through the borehole 202 with enough heat so that it can be used to generate renewable energy in a power plant or for some other use.

[0023] 2B is a simplified cross-sectional view illustrating the extraction of the drill bit 204 from the completed borehole 202. Once the borehole 202 reaches a desired depth, the drill bit 204 may be withdrawn by withdrawing the drilling stem 208. In the absence of a thermodynamic fluid within the borehole 202, such as drilling fluid 210 or working fluid 212, the magma body 100 will cause the end of the borehole 202 within the magma body 100 to collapse. Thus, to maintain the integrity of the sidewalls of the borehole 202 within the magma body 100, i.e., to prevent the sidewalls of the borehole 202 from melting and / or collapsing, drilling fluid 210 may continue to be introduced into the borehole 202 as the drill bit 204 is extracted from the borehole 202. In one embodiment, drilling fluid 210 may continue to be introduced into the borehole 202 through the drilling stem 208 as the drill bit 204 is removed from the borehole. In another embodiment, as the drill bit 204 is being withdrawn from the borehole 202, a fluid conduit 214 can be inserted into the borehole 202 to continue supplying drilling fluid 210 to the borehole 202. Alternatively, the fluid conduit 214 can begin supplying working fluid 212 into the borehole 202 to maintain the integrity of the borehole 202 as the drill bit 204 is being withdrawn and while the borehole 202 is capped with a well head 700 (see FIGS. 7A-C) to form the well 200 shown in FIGS. 2C and 2D. The working fluid 212 can be supplied from a fluid reservoir 216 and withdrawn from the well as working fluid 212' in a vapor phase.

[0024] The drilling fluid 210 may be replaced with a working fluid 212 that has better properties for generating electricity. An example of the working fluid 212 may include fresh water, which is preferred because it is relatively cheap, abundant, and non-polluting. The drilling fluid 210 may be replaced with the working fluid 212 after drilling operations have ceased.

[0025] 2C is a simplified cross-sectional view of well 200 illustrating the introduction of working fluid 212 into fluid conduit 214 for removing drilling fluid 210 from borehole 202. Working fluid 212 may be stored in fluid reservoir 216 and introduced into borehole 202 through fluid conduit 214.

[0026] 2D is a simplified cross-sectional view of completed well-generated steam or another heated working fluid 212 from the working fluid 212. As an example, the working fluid 212 may be sourced from a fluid reservoir 216 and transported to the borehole 202 in a liquid phase. Heat from the magma body 100 is absorbed by the working fluid 212, causing the working fluid 212 to rise through the borehole 202. The working fluid 212 changes from a liquid phase to a gas phase and can then be used to generate electricity from a power plant (not shown). Spent steam can be condensed and returned to the fluid reservoir 216 for reintroduction into the borehole 202.

[0027] Figure 3 is a simplified cross-sectional view of an uncapped well being drilled into a magma body according to an exemplary embodiment. Borehole 202 extends from surface 205, through rock formations 206, through magma top 207, and into magma body 100. In Figure 3, borehole 202 includes a conductor 302 at surface 205 that can be used to attach a well head (e.g., well head 700 of Figures 7A-C) once drilling operations have ceased. In a cased well, casing 209 can be suspended from conductor 302.

[0028] Drilling fluid 210 introduced into borehole 202 creates a temperature gradient within magma body 100 that may be manifested as a layered boundary comprising a fractured rock zone 304 surrounded by a plastic semi-crystalline zone 306. A magma chamber wall 308 separates the plastic semi-crystalline zone 306 from the magma within magma body 100.

[0029] 4A-4C are various cross-sectional views of a partially cased wellbore in accordance with an exemplary embodiment. In particular, FIG. 4A is a simplified cross-sectional view of a partially cased wellbore being drilled into a magma body in accordance with an exemplary embodiment. FIG. 4B is a cross-sectional view of the partially cased wellbore of FIG. 4A taken along line 4B-4B, and FIG. 4C is a more detailed depiction of the stratified boundaries between boreholes 202.

[0030] The borehole 202 shown in Figure 4A extends from the surface 205, through the rock formation 206, past the magma top 207 and into the magma body 100. The borehole 202 is partially cased, i.e., cased only throughout the rock formation 206 using casing 209. The borehole 202 is not cased within the magma body 100.

[0031] In the cross-sectional view shown in Figure 4B, the drilling stem 208 is approximately centrally located within the borehole 202. During drilling, the volume within the interior of the drilling stem 208 may carry drilling fluid 210 from the surface 205 into the borehole 202, and the volume bounded by the exterior surface of the drilling stem 208 and the walls of the borehole 202 may fill with drilling fluid 210 that carries the cuttings to the surface 205. The layered boundaries surrounding the borehole 202, i.e., the fractured rock layer 304, the plastic semi-crystallized zone 306, and the magma chamber wall 308, are shown as a series of substantially concentric rings. The interfaces between the various layers of the layered boundaries are shown in more detail in Figure 4C.

[0032] 5 is a simplified cross-sectional view of a borehole 202 drilled into a magma body 100 in accordance with an exemplary embodiment. A drill bit 204 attached to a drilling shaft 208 drills the borehole 202 from a surface 205 through a rock formation 206 into or near the magma body 100. A drilling fluid 210 is delivered through the drilling stem 208 to an interface between the drill bit 204 and the distal end of the borehole 202. The drilling fluid 210 can quench the magma within the magma body 100 to form a solid phase material that can be cut by the drill bit 204, and the thermodynamic fluid can also lift the cuttings out of the borehole 202.

[0033] In some embodiments, additional fluid may be provided to the borehole 202 to help maintain sidewall integrity, i.e., to keep the sidewall of the borehole 202 from remelting within the magma body 100, if the drilling fluid 210 provided from the drilling stem 208 is insufficient. In one embodiment, the additional fluid is additional drilling fluid 210 provided from a fluid reservoir 216 located at the surface 205 and provided through a fluid conduit 214 that directs the drilling fluid 210 along the sidewall of the borehole 202. The drilling fluid 210 may be provided even after drilling operations have ceased and the well 200 has been completed. For example, the drilling fluid 210 may be provided from the fluid conduit 214 while the drilling stem 208 and drill bit 204 are removed from the borehole 202. The drilling fluid 210 may also be provided to allow for casement of the borehole 202 if the borehole 202 was not cased during the drilling operation.

[0034] If the resulting well is uncaseable or partially cased, the supply of drilling fluid 210 can be stopped once working fluid 212 can be supplied. In some embodiments, fluid conduits 214 can be two or more conduits for supplying different thermodynamic fluids to borehole 202. For example, drilling fluid 210 can be supplied through one of the conduits during drilling. The supply of drilling fluid 210 can be stopped after drilling so that the supply of working fluid 212 can be supplied in preparation for power generation, among other suitable processes.

[0035] If the resulting well is a fully cased well, such as the geothermal well 900 of Figure 9, the drilling fluid 210 can be supplied to the annular region between the sidewall of the borehole 202 and the exterior surface of the casing to prevent the borehole from remelting and collapsing. Once the well 900 is completed, the supply of drilling fluid 210 can be stopped, allowing the borehole 202 to remelt around the end of the casing at the end of the borehole 202. The working fluid 212 can be supplied to the completed well 900 to produce gaseous working fluid 212 for power generation, among other suitable processes.

[0036] 5, in some embodiments, additional drilling fluid 210 may be sprayed radially outward from the drilling stem 208, through openings in the drilling stem 208, or from a fluid conduit (not shown) disposed about the drilling stem 208. The additional drilling fluid 210 may be provided in addition to or instead of the drilling fluid 210 from the drill bit 204 or the fluid conduit 214.

[0037] The drilling fluid 210 and the working fluid 212 may be different fluids or the same fluid. In some embodiments, the drilling fluid 210 and the working fluid 212 are water or consist of water. In another embodiment, the drilling fluid 210 is a fluid having a boiling point that is less than about 150° C., or more specifically, a thermodynamic fluid having a boiling point around 100° C. In another embodiment, the drilling fluid 210 may be a fluid having a boiling point less than 100° C.

[0038] 6A and 6B are various simplified cross-sectional views of a well casing and a more detailed view of a casing weld, according to an exemplary embodiment. In particular, FIG. 6A is a cross-sectional view of a conductor 302 and a casing 209 extending from a surface 205 through a rock formation 206 into a magma body 100. The cross-sectional view shows the location of a weld 600 between the conductor 302 and the casing 209. FIG. 6B shows a more detailed view of the weld 600. In a non-limiting embodiment, the conductor 302 and the casing 209 have a beveled edge at the interface at the joint that can provide a larger surface area for contacting the weld 600.

[0039] 7A-7C are various views of a well head that may be used to cap a well, in accordance with an example embodiment. In particular, FIG. 7A is an elevation view of well head 700 shown attached to conductor 302 suspended within borehole 202. FIG. 7B is a top view of well head 700, and FIG. 7C is another elevation view of well head 700 looking at flange 706.

[0040] Well head 700 is attached to conductor 302 by a mounting flange 704. A fluid conduit 702 passing through well head 700 introduces a fluid, such as working fluid 212, into borehole 202. The gas phase of working fluid 212 rises from borehole 202 into well head 700 and is withdrawn through an outlet defined by flange 706. Flange 706 may be connected to a wing valve 708 for controlling the flow of gas to a power plant (not shown).

[0041] 8 is a simplified cross-sectional view of a partially cased wellbore producing saturated steam from a working fluid, according to an exemplary embodiment. The wellbore 800 is a partially cased wellbore having a casing 209 suspended within a borehole 202 that extends from the surface 205 through rock formations 206 into the magma body 100. The casing 209 does not extend beyond the magma top end 207 of the magma body 100, thereby leaving the portion of the borehole 202 that extends into the magma body 100 uncased. A fluid conduit 214 is disposed within the wellbore 800 and delivers a working fluid 212 to an end of the borehole 202, which is a heat exchange area of ​​the wellbore 800. In the heat exchange area of ​​the wellbore 800, the working fluid 212 absorbs heat and is converted to a gas phase working fluid 212', which in an embodiment where the working fluid 212 is water, may be saturated steam. Gas-phase working fluid 212' traveling down the well 800 to the surface 205 is collected at the well head 700 and directed to a power plant (not shown) for use in producing electricity and / or other products.

[0042] In a non-limiting embodiment, the wellbore 800 depicted in FIG. 8 is configured to maintain a backpressure of at least 1000 pounds per square inch (PSI), and in a more particular embodiment, the wellbore 800 is configured to maintain a backpressure that is at least 2000 PSI. The amount of backpressure is necessary to create a continuous flow of working fluid 212, for example, from a source in fluid reservoir 216, down fluid conduit 214 to the end of borehole 202, back up borehole 202, to a power plant, for example, a steam processing facility (not shown), and optionally back from the steam processing facility to the source. Backpressure can be maintained in the wellbore 800 using conventional equipment, such as one or more pumps, gauges, and pressure regulators, typically represented by pressure generator 804. In this exemplary embodiment of FIG. 8, pressure generator 804 is connected to a fluid conduit 214 that supplies working fluid 212 to the wellbore 800. Other systems that provide the necessary backpressure in the wellbore 800 can be substituted.

[0043] Additionally, the casing 209 of the well 800 has a thickness and / or composition sufficient to sustain the high temperatures and pressures exerted by the fluid carried therein. In some embodiments, the casing 209 is also encased in an insulating layer 802, at least at the end closest to the surface 205. The insulating layer 802 reduces heat loss to reduce the amount of gas phase working fluid 212' that is returned to the condensate at the top of the borehole 202. Although not shown, the fluid conduit 214 may be provided with one or more insulating layers to prevent undesirable heat exchange between the working fluid inside and outside the fluid conduit 214.

[0044] FIG. 9 is a simplified cross-sectional view of a cased well for producing saturated steam from a working fluid according to an exemplary embodiment. Well 900 is like well 800 of FIG. 8, except that casing 209 extends from surface 205 into magma body 100 beyond magma top 207 and is sealed at its end by end cap 904. In this exemplary embodiment, casing 209 is substantially coextensive with the entire length of borehole 202. Once casing 209 is in place, crystallized magma can melt and reform around casing 209 as recrystallized magma. Thus, borehole 202 decreases in diameter from the boundary defined by the dashed line to casing 209. The heat exchange area of ​​well 900 coincides with the portion of casing 209 within magma body 100.

[0045] FIG. 10 is a simplified schematic diagram of a power generation system 1000 according to an exemplary embodiment. The system 1000 includes a geothermal well 1001, which may be any one of the geothermal wells described in this disclosure. The geothermal well 1001 produces a gas phase working fluid 212′ from a liquid phase working fluid 212. The gas phase working fluid 212′ is sent through a fluid conduit 1002 to a power generation facility 1004, which generates power from the gas phase working fluid 212′. In a non-limiting embodiment, the power generation facility 1004 includes one or more turbines (not shown) configured to receive the high pressure, high temperature fluid, i.e., working fluid 212′ in a gas phase, and generate power. The working fluid condensate can be sent to a condensate tank 1008 along with the spent working fluid, i.e., low pressure, low temperature gas phase working fluid 212′, after the spent working fluid is condensed. The fluid can be sent to the condensate tank 1008 through a condensation line 1006. The working fluid 212 in liquid phase may be pumped from the condensate tank 1008 back to the geothermal well 1001 via pump 1010. A check valve 1012 may be placed in the condensate injection conduit 1014 to prevent unwanted backflow. The check valve 1012 may also be used to isolate the pump 1010 to allow for servicing.

[0046] 11 is a cross-sectional view of a partially cased geothermal well according to an exemplary embodiment. The borehole 202 of the geothermal well 1100 is cased through a rock formation 206 and is uncaseable within the magma body 100. The geothermal well 1100 differs from the previously depicted wells in that the borehole 202 transitions into multiple branches 1102 within the magma body 100. In a non-limiting embodiment, the multiple borehole branches 1102 can be drilled by a drilling motor (not shown) that is used to manipulate the orientation of a curved segment of the drilling stem 208 to control the orientation of the drill bit 204. In this non-limiting embodiment, the drilling stem 208 is suspended by a drilling derrick 1104.

[0047] Injection of drilling fluid 210 into each branch during drilling allows the magma in the magma body 100 to be drilled into by the drilling bit 204. Continued introduction of drilling fluid 210 into each branch 1102 upon completion maintains the integrity of the sidewalls of each branch 1102 in the magma body 100. In the exemplary embodiment of FIG. 11, thermodynamic fluid can be introduced into the completed branch 1102 while the drilling bit 204 continues to drill additional branches. The thermodynamic fluid can be stored in a fluid reservoir 216 and piped into the borehole 202 through a fluid conduit 214. Although the fluid conduit 214 is depicted as a single fluid conduit, in another embodiment, the fluid conduit 214 can be multiple fluid conduits, one for each branch 1102, that can extend to an inlet or at least partially into each branch 1102. The thermodynamic fluid may be the drilling fluid 210 used by the drill bit 204 to drill each of the branches 1102 of the borehole 202. In another embodiment, the thermodynamic fluid may be a different fluid than the drilling fluid 210. For example, a working fluid may be injected through fluid conduits 214 into each of the completed branches 1102 of the borehole 202.

[0048] Figures 12 and 13 show different embodiments of geothermal wells with branched wells. In particular, Figure 12 depicts multiple geothermal wells 1100 drilled from the surface 205 through rock formations 206 into the same magma body 100. Within the magma body 100, each of the boreholes 202 may split into multiple branches 1102, thereby increasing production capacity. Figure 13 shows a geothermal well 1300 with boreholes 202 drilled horizontally through the rock formations 206 into the magma body 100. The boreholes 202 may be drilled by a drilling bit attached to a drilling stem extending from a drilling platform 1304.

[0049] 14 is a flowchart of a process for completing a well, according to an example embodiment. The steps of flowchart 1400 may be performed to complete a well, such as well 800 of FIG. 8, well 900 of FIG. 9, or well 1100 of FIG. 11.

[0050] Flowchart 1400 begins at step 1402 by drilling a borehole from the surface toward the magma chamber. In some embodiments, drilling the borehole also includes casing the borehole. The casing may be lowered into the borehole on an underreamer located proximate to the drill bit. The casing may terminate before reaching the magma roof of the magma chamber to form a partially cast wellbore, such as well 800 in FIG. 8, or the casing may extend nearly the entire length of the well to form a fully cast wellbore, such as well 900 in FIG. 9.

[0051] In step 1404, a drilling fluid is delivered to the interface between the drill bit and the end of the borehole being drilled. In some embodiments the drilling fluid is water, and in other embodiments the drilling fluid includes water. The drilling fluid lifts the cuttings out of the borehole and as the borehole approaches and extends into the magma chamber, the drilling fluid quenches the magma to form a solid phase material that can be cut by the drill bit.

[0052] At step 1406, drilling is terminated in response to the borehole reaching a predetermined depth.

[0053] In step 1408, a thermodynamic fluid is supplied into the borehole to maintain the borehole while completing the well. The thermodynamic fluid may be supplied, for example, from the drilling stem and / or from an auxiliary supply conduit, as shown in FIG. 5. The steps for completing the well may vary depending on the type of well. For example, if the well is a partially cased well (see example in FIG. 8), completing the well may include drilling one or more borehole branches, withdrawing the drilling stem and drill bit, casing the borehole from the surface to a depth above the top of the magma if the borehole was not cased during drilling, capping the borehole with a well head, and installing a fluid conduit that supplies the working fluid into the well. The working fluid may be supplied into the well while maintaining a back pressure of at least 1000 PSI or at least 2000 PSI in the well.

[0054] If the well is a fully cased well (see example in FIG. 9), completing the well may include withdrawing the drill stem and drill bit, casing the borehole from the surface to the end of the borehole if the borehole was not cased during drilling, securing the tail cap to the magma chamber, covering the borehole with a well head, and installing a fluid conduit supplying working fluid into the end of the casing located in the well. The working fluid may be supplied into the well while maintaining a back pressure of at least 1000 PSI or at least 2000 PSI in the well. The supply of thermodynamic fluid may be maintained in the annular region between the sidewall of the well and the outer sidewall of the casing while the well is being completed, after which the supply is stopped to allow the sidewall of the borehole to melt and reform against the sidewall of the casing. Additional Embodiments

[0055] The following described embodiments are provided to further support one or more aspects of the present invention.

[0056] In a first embodiment, the present invention is directed to a method for completing a well to extract heat from magma, the method including the steps of drilling a borehole from the surface toward a magma chamber, supplying a drilling fluid to an interface between the drill bit and an end of the borehole, terminating drilling in response to the borehole achieving a predetermined depth, and supplying a thermodynamic fluid to the borehole to maintain the borehole while completing the well.

[0057] In another aspect of the first embodiment, the present invention is directed to a method for completing a well for extracting heat from magma. The method includes drilling a borehole from the surface toward a magma chamber, supplying a drilling fluid to an interface between the drill bit and an end of the borehole, terminating the drilling in response to the borehole achieving a predetermined depth, and supplying a thermodynamic fluid to the borehole to maintain the borehole while completing the well. The method also includes one or more limitations selected from the following:

[0058] The step of delivering the thermodynamic fluid while completing the well bore further includes withdrawing a drilling stem used in the drilling step and capping the well bore with the well head.

[0059] Completing the well bore further includes suspending a casing from at least the surface to an upper end of the magma chamber, and capping the well bore further includes connecting the well head to an end of the casing at the surface.

[0060] The casing extends from the surface into and into the magma chamber, and the distal end of the casing is sealed with a rear end cap.

[0061] While securing the aft end cap to the end of the casing, the thermodynamic fluid is at least partially delivered to the annular volume between the borehole and an exterior surface of the casing.

[0062] The method includes the steps of: in response to securing the aft end cap to the distal end of the casing, stopping flow of thermodynamic fluid into the borehole; remelting at least a portion of the borehole within a magma chamber; and supplying working fluid into the interior volume of the casing and to the distal end of the casing.

[0063] Caping the well with the well head further includes inserting a fluid conduit through the well head and into the well and to a depth that allows fluid to reach a terminus of the conduit.

[0064] Delivering the thermodynamic fluid while completing the well further includes drilling at least one other branch of the borehole.

[0065] Drilling the borehole further includes casing the borehole from the surface to at least an upper end of the magma chamber.

[0066] Casing the borehole further includes casing the entire borehole from the surface to a terminus located within the magma chamber.

[0067] Here, at least a portion of the thermodynamic fluid is supplied from the drilling stem.

[0068] At least a portion of the thermodynamic fluid is provided from a fluid conduit that passes through the well head and is disposed within the wellbore.

[0069] A thermodynamic fluid has a boiling point below 150°C.

[0070] The drilling fluid comprises water and the thermodynamic fluid comprises water.

[0071] The step includes supplying a working fluid into the well while maintaining pressure in the well.

[0072] The working fluid is supplied through an insulated fluid conduit disposed within the wellbore.

[0073] The working fluid is water.

[0074] In a second embodiment, the invention is directed to a well for extracting heat from magma. The well includes a borehole having an opening at a surface and a terminus at a predetermined depth within a magma chamber, a casing disposed within the borehole and extending from the surface to at least an upper end of the magma chamber, a well head connecting with the casing at the surface, and a fluid conduit passing through the well head. The fluid conduit supplies a working fluid to the terminus of the well. Pressure is maintained within the well.

[0075] In another aspect of the second embodiment, the invention is directed to a well for extracting heat from magma. The well includes a borehole having an opening at a surface and a terminus at a predetermined depth within a magma chamber, a casing disposed within the borehole and extending from the surface to at least an upper end of the magma chamber, a well head coupled to the casing at the surface, and a fluid conduit passing through the well head. The fluid conduit provides a working fluid to the terminus of the well. Pressure is maintained within the well. The well also includes one or more constraints selected from the following:

[0076] Pressure is maintained within the wellbore.

[0077] The casing extends only to the upper end of the magma body.

[0078] The casing extends from the surface of the borehole to a terminus terminating within the body of magma.

[0079] The fluid conduit is connected to a pressure generator for providing sufficient pressure to provide a back pressure of at least 1000 PSI.

[0080] The well head is connected to a steam handling facility; and

[0081] The borehole contains multiple branches that radiate outward into the main body of magma.

[0082] Although the embodiments of the present invention have been described with reference to some elements, any elements described in the embodiments described herein are exemplary and may be omitted, substituted, added, combined, or rearranged as applicable to form new embodiments. Those skilled in the art will recognize by reading this specification that such additional embodiments are effectively disclosed herein. For example, if the present invention describes a property, structure, size, shape, arrangement, or composition of an element or a process for making or using an element or combination of elements, the property, structure, size, shape, arrangement, or composition may also be incorporated into any other element or combination of elements, or into a process for making or using an element or combination of elements described herein to provide further embodiments.

[0083] In addition, where an embodiment is described herein as comprising a certain element or group of elements, further embodiments can consist essentially of or consist of the element or group of elements. Also, although the open-ended term "comprising" is generally used herein, further embodiments can be formed by substituting the term "consisting essentially of" or "consisting of."

[0084] Although the present invention has been particularly shown and described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. The inventors expect that those skilled in the art will adopt such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. 1. A method for completing a well, comprising: Drilling a borehole from the surface to a magma chamber; supplying a drilling fluid to an interface between a drill bit and an end of the borehole, the drilling fluid lifting cuttings out of the borehole, the drilling fluid quenching the magma to form a solid phase material that can be cut by the drill bit; terminating the drilling step in response to the borehole achieving a predetermined depth; and supplying a thermodynamic fluid into the borehole to maintain the borehole during well completion.

2. Supplying the thermodynamic fluid during completion of the well bore comprises: A step of drawing out a drilling stem used in the drilling step; 10. The method of claim 1, further comprising the step of capping the borehole with a well head.

3. Completing the well bore includes: suspending a casing from the surface to an upper end of the magma chamber; The step of capping the well comprises: The method of claim 2 , further comprising the step of connecting the well head to an end of the casing at the surface.

4. 4. The method of claim 3, wherein the casing extends from the surface to and into the magma chamber, and ends of the casing are sealed with end caps.

5. 5. The method of claim 4, wherein the thermodynamic fluid is delivered at least in part to the annular volume between the borehole and the exterior surface of the casing while securing the end cap to the end of the casing.

6. in response to securing the end cap to the end of the casing, stopping flow of thermodynamic fluid into the borehole; remelting at least a portion of the borehole within the magma chamber; The method of claim 5 , further comprising the step of: providing a working fluid within the interior volume of the casing and to the distal end of the casing.

7. Capturing the well with the well head includes:

3. The method of claim 2, further comprising inserting a fluid conduit through the well head and into the well to a depth that allows fluid to reach a terminus of the fluid conduit.

8. Supplying the thermodynamic fluid during completion of the well bore comprises:

3. The method of claim 2, further comprising drilling at least one other branch of the borehole.

9. The step of drilling the borehole comprises:

10. The method of claim 1, further comprising casing the borehole from the surface to at least a top of the magma chamber.

10. casing the borehole comprises:

10. The method of claim 9, further comprising casing the entire borehole from the surface to a terminus located within the magma chamber.

11. The method of claim 2 , wherein at least a portion of the thermodynamic fluid is provided from the drilling stem.

12. The method of claim 2 , wherein at least a portion of the thermodynamic fluid is supplied from a fluid conduit disposed in the wellbore through the wellhead.

13. The method of claim 1 , wherein the thermodynamic fluid has a boiling point below 150° C.

14. The method of claim 1 , wherein the drilling fluid comprises water and the thermodynamic fluid comprises water.

15. The method of claim 1 , further comprising: supplying working fluid into the wellbore while maintaining a back pressure of at least 1000 PSI in the wellbore.

16. The method of claim 15 , wherein the working fluid is supplied through an insulating fluid conduit disposed within the wellbore.

17. The method of claim 16 , wherein the working fluid is water.

18. a borehole having an opening at the surface and a terminal at a predetermined depth within the magma body; a casing disposed within the borehole and extending from the surface to at least an upper end of the magma body; a well head connected to the casing at the surface; a fluid conduit passing through the well head, The fluid conduit supplies a working fluid to a terminus of the wellbore, the borehole being maintained at a back pressure of at least 1000 pounds per square inch (PSI).

19. 20. The wellbore of claim 18, wherein pressure within the wellbore is maintained at at least 2000 PSI.

20. The well of claim 18 , wherein the casing extends only to the upper end of the magma body.

21. 20. The well of claim 18, wherein the casing extends from the surface to the end of the borehole terminating within the body of magma.

22. 20. The wellhead of claim 18, wherein the fluid conduit is coupled to a pressure generator for providing sufficient pressure to provide the backpressure of at least 1000 PSI.

23. The well of claim 18 , wherein the well head is connected to a steam handling facility.

24. 20. The well of claim 18, wherein the borehole includes multiple branches that diverge outwardly into a body of magma.

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