CA3133630A1 - Geothermal heating of hydrocarbon reservoirs for in situ recovery - Google Patents

Abstract

The present description relates to a system and method for recovering hydrocarbons or fluids, such as heavy hydrocarbons, from a subsurface fomiation, and more particularly, a system and method for recovering hydrocarbons from a subsurface fommtion comprising a geothemial well. The system comprises a geothermal well and production well, the geothermal well generally comprising a heat-receiving well section and a heat-transmitting well section. The heat-receiving well section generally extends within a geothemial zone of the formation and being configured to be heated by geothemial heat in the geothermal zone and transmit heat upward; and the heat-transmission well section generally extends from the heat-receiving well section and extends into at least a hydrocarbon zone of the formation located above the geothennal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the hydrocarbon zone to promote mobilization of the hydrocarbons and subsequent pumping of the mobilized hydrocarbons for recovery to surface.

Description

GEOTHERMAL HEATING OF HYDROCARBON RESERVOIRS FOR IN SITU
RECOVERY
TECHNICAL FIELD
10001 ] The technical field generally relates to recovering hydrocarbons or fluids, such as heavy hydrocarbons, from a subsurface formation, and more particularly to systems and methods for recovering hydrocarbons from a subsurface formation aided by a geothermal well.
BACKGROUND
10002 ] The general principle of recovering hydrocarbons, such as heavy hydrocarbons, from a subsurface formation involves heating the heavy hydrocarbons or otherwise reducing the viscosity, thereby facilitating recovery via a production well. Existing thermal processes for recovering heavy hydrocarbons typically require a large surface footprint with significant infrastructure, notably for steam generation. For example, steam-assisted gravity drainage (SAGD) processes require water and natural gas to generate steam at the surface so that the steam can be injected into the injection well for heating the heavy hydrocarbons. These processes have drawbacks, such as energy consumption, notable capital expenditure requirements, and CO2 generation.
10003 ] There is therefore a need for an improved technology for recovering hydrocarbons from subsurface reservoirs.
SUMMARY
10004 ] Various systems and methods are described herein for recovering heavy hydrocarbons from a subsurface formation while leveraging geothermal heat present in a lower zone of the formation. Drawing the geothermal heat up to the heavy hydrocarbon zone using a geothermal well can facilitate mobilization and recovery of the heavy hydrocarbons. Various implementations, aspects and applications of the technology are described in further detail herein.
10005 ] In some aspects, there is provided a system for recovering heavy hydrocarbons from a subsurface formation, the system comprising:

Date Recue/Date Received 2021-10-08 a geothermal well comprising:
a heat-receiving well section extending within a geothermal zone of the formation and being configured to be heated by geothermal heat in the geothermal zone and transmit heat upward; and a heat-transmission well section extending from the heat-receiving well section and extending into at least a heavy hydrocarbon zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the heavy hydrocarbon zone to promote mobilization of the heavy hydrocarbons; and a production well located in the heavy hydrocarbon zone and configured to receive mobilized heavy hydrocarbons for recovery to surface.
10006 ] In some aspects, the heavy hydrocarbons may include heavy hydrocarbons, such as heavy oil, and/or bitumen. The hydrocarbons could also include oil or other hydrocarbon fluids.
10007 ] In some aspects, the geothermal well can include an elongated component located in a corresponding wellbore and composed of a heat conductive material, and the heat is transmitted upward from the heat-receiving well section by conduction.
10008 ] The geothermal well can include an insulated casing, which can be a vacuum insulated tubing casing.
10009 ] In some aspects, the geothermal well can further include an upper well section that extends from the heat-transmission well section to the surface.
10010 ] The geothermal well can be configured to receive an injection fluid that is injectable downhole from the surface via the upper well section, and enters the heavy hydrocarbon zone via the heat-transmission well section. The injection fluid may be heated in the heat-transmission section to form a heated fluid, and the heated fluid is injected into the heavy hydrocarbon zone via the heat-transmission well section. In some aspects, the injection fluid is not preheated at the surface. The injection fluid may include a gas, a liquid, or a mixture thereof. The gas can include steam or CO2, while the liquid can include water.

2 Date Recue/Date Received 2021-10-08 10011 ] In some aspects, the geothermal well may be configured such that steam is generated upon heating of the water in the heat-transmission well section, and the steam is injected into the heavy hydrocarbon zone from the heat-transmission well section.
10012 ] In some aspects, the heat-transmission well section includes a tubular liner that includes perforations for injection of the injection fluid into the heavy hydrocarbon zone.
10013 ] The geothermal well may include at least one valve or packer located in a downhole region of the heat-transmission well section to prevent flow of the injection fluid further downhole.
The at least one valve or packer may be located at a downhole end of the heat-transmission well section to prevent flow of the injection fluid into the heat-receiving well section.
10014 ] The geothermal well may also include at least one control valve located at an uphole region of the heat-transmission well section or in the upper well section to control the injection fluid entering the heat-transmission well section.
10015 ] In some aspects, the heat-receiving well section may be configured to receive a hot native fluid from the geothermal zone of the formation, and transport the hot native fluid uphole into the heat-transmitting well section. The hot native fluid may be injected into the heavy hydrocarbon zone via the heat-transmission well section. The hot native fluid may include a gas, a liquid, or a mixture thereof. The gas may include steam or CO2, whereas the liquid may include water.
10016 ] In some aspects, the geothermal well may be configured such that lower pressures that are present ascending up the geothermal well cause the water to flash to form steam which is injected into the heavy hydrocarbon zone via the heat-transmission well section.
10017 ] The geothermal well may include at least one stop valve or packer located in an uphole region of the heat-receiving well section to prevent flow of the native fluid further up the geothermal well.
10018 ] The geothermal well may also include a flow control valve that is located at an uphole region of the heat-receiving well section and configured to control flow of the hot native

3 Date Recue/Date Received 2021-10-08 fluid into the heat-transmission well section. The at least one flow control valve may control the amount of the native fluid entering the heat-transmission well section.
10019 ] In some aspects, the heat-receiving well section may be configured to transmit the heat by conduction to the heat-transmission well section, and the heat-transmission well section is configured to transmit the heat into the heavy hydrocarbon zone by conduction, in the absence of fluid injection into the heavy hydrocarbon zone.
10020 ] In some aspects, the heat-receiving well section may be configured to prevent flow of a native fluid from the geothermal zone of the formation uphole into the heat-transmission well section.
10021 ] In some aspects, the heat-transmission well section may be horizontal and overly at least a portion of the production well. The heat-transmission well section may also be parallel with and vertically spaced apart from the production well.
10022 ] In some aspects, the heat-receiving well section may substantially be perpendicular with respect to the heat-transmission well section. The heat-receiving well section may be generally vertical. The heat-receiving well section may also be generally inclined.
10023 ] In some aspects, the heavy hydrocarbon zone and the geothermal zone are vertically separated from each other by at least one barrier zone of the formation.
10024 ] In some aspects, the heat-receiving well section may have branched well sections or may be a linear well section.
10025 ] In some aspects, there may be a plurality of the geothermal wells associated with one or more production wells. A plurality of the production wells may also be associated with the geothermal well.
10026 ] In some aspects, there is provided a method for recovering heavy hydrocarbons from a subsurface formation, the method comprising:

4 Date Recue/Date Received 2021-10-08 heating a heavy hydrocarbon zone of the formation and mobilizing heavy hydrocarbons contained therein with geothermal heat obtained from a geothermal zone of the formation, wherein the geothermal heat is obtained by a geothermal well comprising:
a heat-receiving well section extending within the geothermal zone of the formation, and being configured to be heated by geothermal heat in the lower geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least the heavy hydrocarbon zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the heavy hydrocarbon zone to promote mobilization of the heavy hydrocarbons; and recovering the mobilized heavy hydrocarbons to surface.
10027 ] In some aspects, the heating and the recovering are performed simultaneously; or wherein the heating is performed as a pretreatment step prior to recovering the mobilized heavy hydrocarbons from the subsurface formation.
10028 ] In some aspects, the heating of the heavy hydrocarbon zone may be performed by conduction of the geothermal heat through the heat-receiving well section and the heat-transmission well section and into the heavy hydrocarbon zone in the absence of fluid injection into the geothermal well.
10029 ] In some aspects, the heating of the heavy hydrocarbon zone may be performed by conduction of the geothermal heat from the heat-receiving well section to the heat-transmission well section, and by downhole injection of an injection fluid that is heated in the heat-transmission well section and then injected into the heavy hydrocarbon zone.
10030 ] In some aspects, the heating of the heavy hydrocarbon zone may include introducing a circulation fluid downhole into the geothermal well, wherein the circulation fluid is circulated through the heat-receiving well section to be heated to form a heated fluid, and then the heated fluid is transported to the heat-transmission well section for injection into the heavy Date Recue/Date Received 2021-10-08 hydrocarbon zone or for indirect heating of the heavy hydrocarbon zone. The circulation fluid may include a gas, a liquid, or a mixture thereof. The gas may include steam or CO2, whereas the liquid may include water. In some aspects, steam may be generated as the heated fluid upon heating of the water in the heat-receiving well section, and the steam is injected into the heavy hydrocarbon zone from the heat-transmission well section.
10031 ] In some aspects, the heating of the heavy hydrocarbon zone may be performed by conduction of the geothermal heat from the heat-receiving well section to the heat-transmission well section, and by injection of a hot native fluid that is received from the geothermal zone of the formation through heat-receiving well section, transported uphole to the heat-transmission well section, and then injected into the heavy hydrocarbon zone. The native fluid may include a gas, a liquid, or a mixture thereof. The gas may include steam or CO2, whereas the liquid may include water.
10032 ] In some aspects, lower pressures that are present ascending up the geothermal well cause the water to flash to form steam which is injected into the heavy hydrocarbon zone via the heat-transmission well section.
10033 ] In some aspects, the recovering of the mobilized heavy hydrocarbons may be performed by gravity drainage.
10034 ] In some aspects, there is provided a method for recovering hydrocarbons from a subsurface formation, the method comprising transferring geothermal heat from a geothermal zone of the formation to a hydrocarbon zone located above the geothermal zone by conduction to promote mobilization of the hydrocarbons for production thereof to surface.
The hydrocarbons may include heavy hydrocarbons.
10035 ] In some aspects, there is provided a method for recovering hydrocarbons from a subsurface formation, the method comprising transferring geothermal heat from a geothermal zone of the formation to a hydrocarbon zone located above the geothermal zone without transferring the geothermal heat to surface to promote mobilization of the hydrocarbons for production thereof to the surface. The hydrocarbons may include heavy hydrocarbons.

Date Recue/Date Received 2021-10-08 10036 ] In some aspects, there is provided a method for heating and recovering a fluid in a subsurface formation, the method comprising:
heating a fluid-containing zone of the formation with geothermal heat obtained from a geothermal zone of the formation, wherein the geothermal heat is obtained by a geothermal well comprising:
a heat-receiving well section extending within the geothermal zone of the formation, and being configured to be heated by geothermal heat in the lower geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least the fluid-containing zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the fluid-containing zone to heat fluids contained therein; and recovering heated fluid to surface.
10037 ] In some aspects, there is provided a system for recovering hydrocarbons from a subsurface formation, the system comprising:
a geothermal well comprising:
a heat-receiving well section extending within a geothermal zone of the formation and being configured to be heated by geothermal heat in the geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least a hydrocarbon zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the hydrocarbon zone to promote mobilization of the hydrocarbons; and Date Recue/Date Received 2021-10-08 a production well located in the hydrocarbon zone and configured to receive mobilized hydrocarbons for recovery to surface.
10038 ] In some aspects, there is provided a method for recovering hydrocarbons from a subsurface formation, the method comprising:
heating a hydrocarbon zone of the formation and mobilizing hydrocarbons contained therein with geothermal heat obtained from a geothermal zone of the formation, wherein the geothermal heat is obtained by a geothermal well comprising:
a heat-receiving well section extending within the geothermal zone of the formation, and being configured to be heated by geothermal heat in the lower geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least the hydrocarbon zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the hydrocarbon zone to promote mobilization of the hydrocarbons; and recovering the mobilized hydrocarbons to surface.
BRIEF DESCRIPTION OF THE DRAWINGS
10039 ] For a better understanding of the aspects and implementations described herein and to show more clearly how they may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings which show exemplary implementations, and in which:
10040 ] Fig. 1 is a side view schematic of a system for recovering heavy hydrocarbons according to one example implementation. The system comprises a geothermal well comprising a heat-receiving well section and a heat-transmitting well section, where the geothermal well heats the heavy hydrocarbons by conduction of heat from a hot geothermal zone up to the heavy Date Recue/Date Received 2021-10-08 hydrocarbon zone. Heated heavy hydrocarbons are then recovered to the surface via a production well.
10041 ] Fig. 2 is a side view schematic of the system for recovering heavy hydrocarbons according to a second example implementation. The system comprises a geothermal well comprising a heat-receiving well section and a heat-transmitting well section, where the geothermal well heats the heavy hydrocarbons by conduction of heat from a hot geothermal zone up to the heavy hydrocarbon zone, as well as by injection of a fluid from the surface that is heated in heat-transmitting well section and injected into the heavy hydrocarbon zone. Heated heavy hydrocarbons are then recovered to the surface via a production well.
10042 ] Fig. 3 is a side view schematic of the system for recovering heavy hydrocarbons according to a third example implementation. The system comprises a geothermal well comprising a heat-receiving well section and a heat-transmitting well section, where the geothermal well heats the heavy hydrocarbons by conduction of heat from a hot geothermal zone up to the heavy hydrocarbon zone. In addition, a hot native fluid from the hot geothermal zone flows into the geothermal well and is transported from the heat-receiving well section up to the heat-transmission well section for injection into the heavy hydrocarbon zone. Heated heavy hydrocarbons are then recovered to the surface via a production well.
10043 ] Fig. 4 is a close-up side view schematic of the heat-receiving well section, according to one example implementation.
10044 ] Fig. 5 is a close-up side view schematic of the upper well receiving section, according to one example implementation.
10045 ] Fig. 6 is a close-up side view schematic of the heat-transmitting well section, according to one example implementation.
10046 ] Fig. 7 is a close-up side view schematic of the heat-transmitting well section, according to one example implementation.
10047 ] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of Date Recue/Date Received 2021-10-08 the elements may be exaggerated relative to other elements for clarity.
Nevertheless, for disclosure purposes, it should be understood that the relative proportions of the various elements as shown in the figures are disclosed.
DETAILED DESCRIPTION
10048 ] The present description relates to systems and methods for recovering heavy hydrocarbons from a subsurface formation, as shown for example in Figs. 1-4.
The systems and methods described herein leverage the use of a geothermal well to obtain geothermal heat from a low zone of the formation and transport that heat up to a heavy hydrocarbon zone to heat and mobilize the hydrocarbons to facilitate recovery. The geothermal heat can be sent directly from the geothermal zone to the heavy hydrocarbon zone by conduction via completion equipment in the well and/or by allowing hot native fluid to flow up through the well for injection into the heavy hydrocarbon zone. Optionally, a fluid can be injected from surface and can be heated by the geothermal heat and injected into the reservoir.
10049 ] More particularly, the system can include a geothermal well that brings heat from the hot geothermal zone up to the heavy hydrocarbon zone for heating the heavy hydrocarbons, thereby reducing the viscosity of the heavy hydrocarbons for facilitated recovery to the surface by a nearby production well. The systems and methods described herein harness geothermal heat for directly heating hydrocarbons, and therefore provide enhancements in terms of efficiency and environmental sustainability.
Referring now to Figs. 1 to 4, the present technology relates to a system 10 for recovering heavy hydrocarbons 12 from a subsurface formation. The system 10 includes a geothermal well 14 that includes a heat-receiving well section 16 and a heat-transmission well section 18, and the system also includes a production well 20. The heat-receiving well 16 section extends within a geothermal zone 22 of the formation and is configured to be heated by geothermal heat in the geothermal zone 22 and to transmit the heat upward. The heat-transmission well section 18 extends from the heat-receiving well section 16 into at least a heavy hydrocarbon zone 24 of the formation located above the geothermal zone 22. The heat-transmission well section 18 is configured to receive heat from the heat-receiving well section 16 and to transmit the heat into the heavy hydrocarbon zone 24 to promote mobilization of the heavy hydrocarbons 12. The Date Recue/Date Received 2021-10-08 production well 20 is located in the heavy hydrocarbon zone 24 and is configured to receive mobilized heavy hydrocarbons 12 for recovery to the surface 26.
10050 ] As used herein, the term "hydrocarbons" may refer to any hydrocarbon that is present in a subsurface formation for recovery to the surface. The hydrocarbons may in include "heavy" hydrocarbons having a relatively high viscosity that would create difficulties for in situ recovery. Heavy hydrocarbons may include heavy oil, crude oil and bitumen, for example.
Hydrocarbons may be localized in subsurface formations termed "hydrocarbon zones" or reservoirs. In some cases, heavy hydrocarbons have a low API (American Petroleum Institute) gravity. In some cases, the heavy hydrocarbons have an API gravity that is lower than 30, 25, 20, 15, or 10. The heavy hydrocarbons can be recovered as oil-water emulsions, due to native water or injected water or steam. It is noted that the present technology may be useful for the recovery and/or production of various hydrocarbon fluids, including light crude oil, shale oil, or vapour phase hydrocarbons such as natural gas, where geothermal heating can provide one or more benefits. It is also possible to apply the techniques described herein to heat other types of fluids that are present in formations, such as water, brine, and the like.
10051 ] As used herein, the term "mobilized" refers to hydrocarbons that have a reduced viscosity for facilitated recovery. Heating, for example, may be one method for reducing the viscosity of hydrocarbons and promoting their mobilization. In some implementations, heating hydrocarbons to at least 100 C may be sufficient for promoting mobilization.
Optimal temperature ranges for mobilization may be at least within 150 C to 300 C, however, in areas of higher pressure, a lower temperature (<100 C) may be sufficient to heat and mobilize the hydrocarbons.
In some implementations, the resulting viscosity of mobilized hydrocarbons is preferably less than about 1000 cP (centipoise), less than about 750 cP, less than about 500 cP, less than about 250 cP, less than about 100 cP, or less than about 50 cP.
10052 ] The subsurface formations including the heavy hydrocarbon zones 24 may be located at various distances from a geothermal zone 22, and may be separated by one or more barriers. Barrier layers may include a low-permeability stratum in the formation, and may be formed of shale or mud, for example. The geothermal well 14 may be configured to increase or decrease the length of the heat-receiving well section 16 and/or the heat-transmission well section Date Recue/Date Received 2021-10-08 18 depending on the position of the heavy hydrocarbon zone 24 with respect to the geothermal zone 22. In some cases, the heavy hydrocarbon zone 24 and the geothermal zone 22 are vertically separated from each other. Alternatively, the heavy hydrocarbon zone 24 and the geothermal zone 22 are horizontally separated from each other.
10053 ] In some implementations, the heat-receiving well section 16 is generally perpendicular with respect to the heat-transmission well section 18, especially when the heat-transmission well section 18 is generally horizontal and the heat-receiving well section 16 is generally vertical. The heat-receiving well section 16 may be generally vertical or generally inclined, horizontal, or directional. In some implementations, the heat-receiving well section 16 has branched well sections or is an unbranched well section.
10054 ] In some implementations, the heat-transmission well section 18 is horizontal and overlies at least a portion of the production well 20. In some cases, the heat-transmission well 18 section is parallel with and vertically spaced apart from the production well 20, and forms a well pair configuration with the production well 20. The heat-transmitting well section 18 may also have branched well sections or may be an unbranched well section. While the well pair confirmation is shown in the figures, it is also noted that the heat-transmission well section 18 can be located above one or more production wells 20 and oriented at various angles rather than being directly above and parallel with the production well 20.
10055 ] In some implementations, the geothermal well 14 includes an upper well section 28 that extends from the heat-transmission well section 18 to the surface 26. The upper well section 28 is formed during the initial drilling of the geothermal well 14 and may simply be kept as a wellbore access. In some cases, the upper well section 28 is used to inject an injection fluid 32 downhole into the heat-transmitting well section 16, as will be described in further detail below.
10056 ] In some implementations, the system includes a plurality of geothermal wells 14 associated with one or more production wells 20. The geothermal wells 14 can be provided in various arrangements and patterns with respect to each other and with respect to the production wells 20. The system may include a combination of different geothermal wells, as shown by different implementations herein, associated with one or more production wells 20. For example, one geothermal well 14 can be configured for fluid injection, while another geothermal well 14 Date Recue/Date Received 2021-10-08 can be configured to transfer geothermal heat by conduction without fluid injection. In addition, there may be a plurality of production wells associated with a geothermal well. Finally, the systems, methods, or geothermal wells described herein may be partially or completely combined with existing in situ recovery systems and methods for recovering heavy hydrocarbons, such as but not limited to the SAGD process. For example, one or more SAGD well pairs could be located close to and associated with one or more of the geothermal wells 14.
First Implementation 10057 ] Fig. 1 illustrates the system 10 that includes the geothermal well 14 which heats the heavy hydrocarbons 12 by conduction of heat from the hot geothermal zone 22 to the heavy hydrocarbon zone 24 where fluid does not flow into the heat-transmission section 18 from the surface or from the heat-receiving section 16.
10058 ] According to this example implementation, the geothermal well 14 includes an elongated component 30 located in the wellbore of the geothermal well and composed of a heat conductive material, and the heat is transmitted upward (or "uphole" as depicted by the arrows in Fig. 1) from the heat-receiving well section 16 by conduction. The elongated component 30 may be, but is not limited to, a rod, a cable or a tubular. The elongated component 30 can be constructed so as to promote heating from the geothermal zone, conducting heat up to the heat-transmission section 18, and then releasing the heat into the heavy hydrocarbon zone 24.
The elongated component 30 can have an outer surface that is in direct contact with the inner wall of the wellbore at locations where heat is transported into the hydrocarbon zone 24, and it can be insulated from the formation in locations where heat transmission to the outer formations is to be minimized (e.g., through barrier zones or any zones that are in between the geothermal zone and the heavy hydrocarbon zone). The heat conductive material may be a metal, such as to steel. The elongated component 30 may extend between a lower part of the heat-receiving well section 16 to an upper part of the heat-transmitting well section 18, although it can have various dimensions and constructions depending on the application. Heat released by the heat-transmitting well section 18 into the reservoir is depicted as wavy lines in Fig. 1.
10059 ] The geothermal well 14 may further include an insulated casing.
The insulating casing may enclose the elongated component 30 to prevent heat loss in certain locations. The Date Recue/Date Received 2021-10-08 insulated casing may be a vacuum insulated tubing (VIT) casing. The insulated casing surface may therefore be in direct contact with the inner wall of the wellbore at locations where heat is transported into the hydrocarbon zone 24, to minimize heat loss from the wellbore to the outer formation. The insulation can thus be provided in between the heat-receiving and heat-releasing sections of the geothermal well.
10060 ] The geothermal well 14 also includes the upper well section 28 that extends from the heat-transmission well section 18 to the surface 26. The upper well section 28 is formed during drilling and may be completed in various ways depending on the desired use.
For example, for this example implementations, the upper well section 28 may simply be a wellbore access (e.g., for inspection, maintenance or measurements) and thus is not equipped for injection or production.
The upper well section 28 could also be completed so that little to no geothermal heat or fluid can travels up from the heat-transmission well section 18, and therefore could be provided with appropriate equipment for this purpose.
Second Implementation 10061 ] Fig. 2 illustrates the system 10 which includes the geothermal well 14 which heats the heavy hydrocarbons 12 by conduction of heat from the hot geothermal zone 22 to the heavy hydrocarbon zone 24, and in this sense is similar to the system 10 according to the first implementation, but it also involves providing an injection fluid 32 from the surface 26. The injection fluid 32 is provided from the surface 26 downhole and into the heat-transmitting well 18 section. The injection fluid 32 is heated by the heat-transmitting well 18 section, which has received geothermal heat, and is injected into the heavy hydrocarbon zone 24.
This implementation therefore includes geothermal heating as well as fluid injection from the surface to help mobilize the heavy hydrocarbons 12.
10062 ] According to this example implementation, the injection fluid 32 is introduced via the upper well section 28 and flows down into the heat-transmitting well section 18. The upper well section 28 may therefore be coupled to injection equipment at surface 26 which can be configured depending on the type and state of the injection fluid (e.g., vapor, liquid, heated, ambient). The injection fluid 32 is then heated by the heat-transmitting well section 18, which is heated geothermally by conduction as described herein. The heated injection fluid 32 is then Date Recue/Date Received 2021-10-08 injected into the heavy hydrocarbon zone 24 to help mobilize the heavy hydrocarbons 12. The heavy hydrocarbons 12 may therefore be heated by conduction of geothermal heat from the heat-transmitting well 18 section into the hydrocarbon zone, as well as by contact with the heated injection fluid 32 entering the hydrocarbon zone 24. The injection fluid 32 can help mobilize the heavy hydrocarbons by heating and also be other mechanisms as some injection fluids can mix with the hydrocarbons and help reduce viscosity.
10063 ] For this implementation, the heat-transmitting well section 18 is configured to allow the injection fluid to flow into the heavy hydrocarbon zone 24, and thus provides fluid communication between the wellbore and the surrounding reservoir. For instance, the heat-transmitting well section 18 may include perforations 34 for releasing the heated injection fluid 32 into the heavy hydrocarbon zone 24, as shown in Fig. 6. The perforations 34 can be provided through a tubular liner that facilitates transmission of the geothermal heat.
The heat-transmitting well section 18 may include flow control devices 35 or other completion systems to enable injection of the heated injection fluid 32 into the heavy hydrocarbon zone 24, as shown schematically in Fig. 7. The heat-transmitting well section 18 may include a steel tubing that is perforated for injection of the injection fluid 32. The injection fluid 32 can be delivered from surface using a pump or a compressor, for example, depending on the type of injection fluid introduced into the geothermal well.
10064 ] The injection fluid 32 may include a gas, liquid, or a mixture of gas and liquid. The gas may include steam or CO2. The liquid may include water. In some implementations, the injection fluid 32 is not preheated prior to downhole injection. In some cases, the injection fluid 32 is a liquid (e.g., liquid comprising water) which is introduced as a liquid and is heated in the heat-transmitting well section 18 and is thus converted partially or completely into a gas (e.g., steam) which is injected into the heavy hydrocarbon zone 24. This downhole vaporization of the injection fluid is enabled by the geothermal heat in the heat-transmitting well section 18.
Alternatively, the injection fluid can be in liquid phase when introduced into the geothermal well and also when injected into the reservoir.
10065 ] When fluid is injected into the reservoir, it can form a mixture with the mobilized heavy hydrocarbons 12, which is then recovered as the production fluid. The production fluid can Date Recue/Date Received 2021-10-08 include hydrocarbons, injection fluid as well as other native fluids such as water and light gases.
The production fluid is treated at surface. Heavy hydrocarbons 12 may be separated from the other components of the production fluid by various methods, such as by using separators (e.g., gas separator, oil/water separator, vapor/liquid separators, etc.). In some implementations, the produced water and/or gas/CO2 that is separated from the hydrocarbons may be treated and reused as part of the injection fluid 32. In general, the production fluid can be treated to remove the injection fluid for reuse in the system 10.
10066 ] In the second implementation, the geothermal well 14 can be equipped to allow the injection fluid to pass from the surface, into the heat-transmission well section, and into the reservoir without flowing further down the geothermal well 14. For example, the geothermal well can have a packer, valve or another device that prevents fluid flow from the heat-transmission well section 18 down into the heat-receiving well section 16. The flow prevention device can be deployed at a downhole end of the heat-transmission well section 16, for example. Examples of such a packer 40 and valve 38 are schematically illustrated in this arrangement in Fig. 6.
Third Implementation 10067 ] Fig. 3 illustrates the system 10 which includes the geothermal well 14 that heats the heavy hydrocarbons 12 by conduction of heat from the hot geothermal zone 22 to the heavy hydrocarbon zone 24, and in this sense is similar to the system 10 according to the first implementation, but it also involves allowing a hot native fluid to flow from the geothermal zone 22 through the geothermal well 14 and into the heavy hydrocarbon zone 24. The hot native fluid 36 is obtained from the hot geothermal zone 22 and is transported uphole from the heat-receiving well section 16 into the heat-transmission well section 18 for injection into the heavy hydrocarbon zone 24.
10068 ] According to this example implementation, the hot native fluid 36 is fluid that is originally present in hot geothermal zone 22. The heat-receiving well section 16 may comprise a fluid inlet 41 (see Fig. 4) that receives the hot native fluid 36 from the hot geothermal zone 22 and due to pressure differential the hot native fluid 36 flows up to the heat-transmitting well section 18. The fluid inlet 41 could be configured to be operable between an open position and a closed position to control whether the hot native fluid can enter the geothermal well 14. The fluid inlet 41 Date Recue/Date Received 2021-10-08 may be configured to work independently or in conjunction with the elongated component 30 (heat conductive material). The native fluid is at a higher pressure compared to the heat-transmitting well section 18 and thus the heat-receiving well section 16 provides a conduit for passage of the native fluid to the lower pressure region. The hot native fluid 36 may then be injected into the heavy hydrocarbon zone 24 via the perforations 34 or other flow control devices 35of the heat-transmitting well section 18. The heavy hydrocarbons 12 may therefore be heated by conduction of geothermal heat via the heat-transmitting well 18 section, and by injecting the hot native geothermal fluid 36 that is transported uphole into the heat-transmitting well section 18.
10069 ] The hot native fluid 36 may include gas, liquid, or a mixture of gas and liquid, depending on the fluids native to the particular geological formation. Due to lower pressures that are present ascending up the geothermal well 14, the hot native fluid 36, which may begin as a liquid (e.g., water), may flash to form a gas (e.g., steam) which is injected into the heavy hydrocarbon zone 24 via the heat-transmission well section 18. The hot native fluid 36 may include steam from its initial phase within the hot geothermal zone 22 and be injected as steam and/or hot water in the heat-transmission well section 18. In some instances, the hot native fluid 36 is kept hot or is further heated by simultaneous conduction of geothermal heat in the heat-receiving well section 16 and heat-transmitting well section 18, as described in the first implementation.
10070 ] When native fluid is allowed to flow up and into the hydrocarbon zone, it can form a mixture with the mobilized heavy hydrocarbons 12, which is then recovered as the production fluid. The production fluid can include hydrocarbons, native fluid from the geothermal zone, as well as native fluids from the hydrocarbon zone. The production fluid is treated at surface. Heavy hydrocarbons 12 may be separated from the other components of the production fluid by various methods, such as by using separators (e.g., gas separator, oil/water separator, vapor/liquid separators, etc.). In some implementations, the produced water and/or gas/CO2 that is separated from the hydrocarbons may be treated and disposed of or used as injection fluid in another well.
10071 ] In the third implementation, the geothermal well 14 can be equipped to allow the hot native fluid to pass from the geothermal zone, up through the heat-receiving well section, into the heat-transmission well section, and then into the reservoir without flowing further up the geothermal well 14. For example, the geothermal well can have an uphole packer 40a, an uphole Date Recue/Date Received 2021-10-08 valve 38a or another device that prevents fluid flow from the heat-transmission well section 18 up the upper section of the geothermal well. The flow prevention device can be deployed at an uphole end of the heat-transmission well section 16, for example. Examples of such a packer 40a and valve 38a are schematically illustrated in this arrangement in Fig. 7.
Variant implementations 10072 ] While three example implementations have been described above, it is noted that one or more of the implementations can be used over time for a given system.
For example, a geothermal well 14 could be initially operated according to the first implementation with no fluid injection from the surface or the geothermal zone, and then the geothermal well could be subsequently operated according to the second or third implementation by allow the appropriate fluid flow and injection. For instance, the geothermal well could be equipped with valves that could be operated manually or remotely in an open or closed position to allow fluid to flow from surface or from the geothermal zone into the heat-transmission well section and then into the hydrocarbon zone. The geothermal well could also be recompleted to switch operation to another implementation.
10073 ] It is also possible for a given geothermal well to switch operation between the second and third implementations. For instance, referring to Figs. 4-7, the geothermal well 14 could be operated with fluid injection from the surface where the uphole valve 38a is open and the downhole valve 38 is closed; and then the operating mode could be switched by ceasing fluid injection from the surface, closing the uphole valve 38a, opening the downhole valve 38, and opening the fluid inlet 41 to allow native fluid flow into the geothermal well 14. It may be of interest to begin the hydrocarbon recovery process using the third implementations to leverage the hot native fluids present in the geothermal zone, and then if or when the hot native fluids become depleted the process can switch to fluid injection from the surface. In this manner, the operating mode of the geothermal well 14 could be modified between the first, second and third implementations, if desired.
10074 ] In addition, the systems according to the first, second and third implementations may be used alone or in combination for heating and/or recovery heavy hydrocarbons. The systems described herein may be used alone or in combination with other conventional systems used for Date Recue/Date Received 2021-10-08 heating and/or recovery of heavy hydrocarbons. Preferably, the systems described herein do not utilize surface boilers or steam as an injection fluid. The systems described herein preferably minimize the use of non-renewable energy sources for heating and/or recovering heavy hydrocarbons.
10075 ] In some cases, the system 10 according to the first implementation is used alone.
Therefore, the heat-receiving well section 16 is configured to transmit the heat by conduction to the heat-transmission well section 18, and the heat-transmission well section 18 is configured to transmit the heat into the heavy hydrocarbon zone 24 by conduction, in the absence of fluid injection (either of hot native fluid 36 or injection fluid 32) into the geothermal well 14 and the heavy hydrocarbon zone 24.
10076 ] As mentioned above, the geothermal well 14 may include one more valves and/or packers, or other completion devices, to control uphole or downhole flow of fluids. The one or more valves and/or packers may be located at various points of the heat-receiving well section 16, heat-transmitting well section 18, and/or the upper well section 28, as shown in Figs. 4-7.
10077 ] The geothermal well 14 may include at least one downhole valve 38 or packer 40 located in a downhole region of the heat-transmission well section 18 to prevent flow of the injection fluid 32 further downhole. The at least one downhole valve 38 or packer 40 may be located at a downhole end of the heat-transmission well section 18 to prevent flow of the injection fluid 32 into the heat-receiving well section 16. It is also possible to provide multiple downhole isolation devices, such as valves or packers, at various locations along the heat-transmission well section 18 and/or the heat-receiving well section 18, and to operate the downhole isolation devices to achieve desired fluid injection effects.
10078 ] The geothermal well 14 may include at least one control valve or uphole valve 38a located at an uphole region of the heat-transmission well section 18 or in the upper well section 28. The control valve 38a can be configured and operated to control the injection fluid 32 entering the heat-transmission well section 18. Control of the injection fluid can also be achieved using the surface equipment to control injection rate or pressure of the fluid.

Date Recue/Date Received 2021-10-08 10079 ] The downhole and/or uphole valves 38/38a or the downhole and/or uphole packers 40/40a can be configured to prevent fluid flow further up the geothermal well 14, which may be desired to stop transfer of heat and/or hot native fluid 36 from the heat-receiving well section 16 or heat-transmitting well section 18 further uphole or for well control purposes. The downhole/uphole valves 38/38a and/or the downhole/uphole packers 40/40a can be located in various parts of the heat-transmission well section 18, as shown in Figs. 6 and 7 for example.
10080 ] The geothermal well 14 may include a fluid circulation system that allows fluid to circulate without being injected into the reservoir. For example, the geothermal well may be configured such that hot circulation fluid is circulated from the surface down into the heat-transmission well section 18 to provide additional heat to the reservoir. The circulation fluid could be steam, but since the steam is not injected into the reservoir the condensate does not require substantial water treatment before being reused to generate additional steam.
It is also possible to configure the fluid circulation system to receive the hot native fluid and allow it pass up and through the heat-transmission well section 18 without being injected into the reservoir.
10081 ] The downhole and/or uphole valves 38/38a or the downhole and/or uphole packers 40/40a can also be configured to prevent hot native fluid 36 backflow or injection fluid 32 flow downhole into the geothermal well 14. This may be desired to stop transfer of heat and/or fluid from the heat receiving well section 16 or heat-transmitting well section 18 further downhole, or for well control purposes. The downhole/uphole valves 38/38a and/or the downhole/uphole packers 40/40a can be located in various parts of the heat-receiving well section 16 or the heat-transmission well section 18, as shown in Figs. 5-7 for example.
Methods for heating and recovering heavy hydrocarbons 10082 ] According to another general aspect of the technology, there is described a method for heating and/or recovering heavy hydrocarbons 12 from an underground reservoir.
10083 ] According to another general aspect of the invention, there is described a method for recovering heavy hydrocarbons 12 from a subsurface formation, the method comprising transferring geothermal heat from a geothermal zone 22 of the formation to a heavy hydrocarbon Date Recue/Date Received 2021-10-08 zone 24 located above the geothermal zone 22 by conduction to promote mobilization of the heavy hydrocarbons 12 for recovery thereof to surface 26.
10084 ] According to another general aspect of the invention, there is described a method for recovering heavy hydrocarbons 12 from a subsurface formation, the method comprising transferring geothermal heat from a geothermal zone 22 of the formation to a heavy hydrocarbon zone 24 located above the geothermal zone 22 without transferring the geothermal heat to surface 26 to promote mobilization of the heavy hydrocarbons 12 for recovery thereof to the surface 26.
According to one example implementation, there is described a method for recovering heavy hydrocarbons 12 from a subsurface formation, wherein the method includes heating a heavy hydrocarbon zone 24 of the formation and mobilizing heavy hydrocarbons 12 contained therein with geothermal heat obtained from a geothermal zone 22 of the formation, wherein the geothermal heat is obtained by a geothermal well 14. The geothermal well 14 includes a heat-receiving well section 16 extending within the geothermal zone 22 of the formation, and is configured to be heated by geothermal heat in the lower geothermal zone 22 and transmit heat upward.
The geothermal well 14 also includes a heat-transmission well section 18 extending from the heat-receiving well section 16 and extending into at least the heavy hydrocarbon zone 24 of the formation located above the geothermal zone 22, the heat-transmission well section 18 being configured to receive heat from the heat-receiving well section 16 and transmit heat into the heavy hydrocarbon zone 24 to promote mobilization of the heavy hydrocarbons12 The method further includes recovering the mobilized heavy hydrocarbons 12 to surface 26.
10085 ] The methods described herein may utilize the systems 10 or geothermal wells 14 according to the example implementations described herein, either alone or in combination.
10086 ] Recovering mobilized heavy hydrocarbons 12 may involve the use of one or more production wells 20 located nearby the geothermal wells 14. In some cases, the recovering of the mobilized heavy hydrocarbons 12 is performed by gravity drainage. In some cases, the heating and the recovering are performed simultaneously. Alternatively, the heating is performed as a pretreatment step prior to recovering the mobilized heavy hydrocarbons 12 from the subsurface formation. The geothermal heating methods can be used for starting up a well pair or a well to be used for injection. The geothermal heating methods can be used where the geothermal well Date Recue/Date Received 2021-10-08 operates in conjunction with various other wells and in situ recovery methods, such as SAGD and CSS, where the geothermal well is located above, beside, below or offset with respect to another well that recovers production fluid.
10087 ] In some implementations, the heating of the heavy hydrocarbon zone 24 is performed by conduction of the geothermal heat through the heat-receiving well section 16 and the heat-transmission well section 18 and into the heavy hydrocarbon zone 24 in the absence of fluid injection into the geothermal well 14 and/or heavy hydrocarbon zone 24.
10088 ] In some implementations, the heating of the heavy hydrocarbon zone 24 is performed by conduction of the geothermal heat from the heat-receiving well section 16 to the heat-transmission well section 18, and by downhole injection of an injection fluid 32 that is heated in the heat-transmission well section 18 and then injected or released into the heavy hydrocarbon zone 24.
10089 ] In other implementations, the heating of the heavy hydrocarbon zone 24 is performed by conduction of the geothermal heat from the heat-receiving well section 16 to the heat-transmission well section 18, and by injection of a hot native fluid 36 that is received from the geothermal zone 22 of the formation through heat-receiving well section 16, transported uphole to the heat-transmission well section 18, and then injected into the heavy hydrocarbon zone 24.
10090 ] In some implementations, the heating of the heavy hydrocarbon zone 24 includes a circulation fluid downhole into the geothermal well 14, wherein the circulation fluid is circulated through the heat-receiving well section 16 to be heated to form a heated fluid 32, and then the heated fluid is transported to the heat-transmission well section 18 for injection into the heavy hydrocarbon zone 24 or for indirect heating of the heavy hydrocarbon zone 24.
10091 ] It will be appreciated that, for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the Figures to indicate corresponding or analogous elements or steps. In addition, numerous specific details are set forth in order to provide a thorough understanding of the exemplary implementations described herein.
However, it will be understood by those of ordinary skill in the art, that the implementations described herein may be practiced without these specific details. In other instances, well-known Date Recue/Date Received 2021-10-08 methods, procedures and components have not been described in detail so as not to obscure the implementations described herein. Furthermore, this description is not to be considered as limiting the scope of the implementations described herein in any way but rather as merely describing the implementation of the various implementations described herein.
10092 ] The use of the word "a" or "an" when used in conjunction with the term "comprising" in the claims and/or the specification may mean "one" but it is also consistent with the meaning of "one or more", "at least one", and "one or more than one".
10093 ] As used in this specification and claim(s), the words "comprising"
(and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes"
and "include") or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.
10094 ] Other objects, advantages and features of the present description will become more apparent upon reading of the following non-restrictive description of specific implementations thereof, given by way of example only with reference to the accompanying drawings.

Date Recue/Date Received 2021-10-08

Claims (58)

1. A system for recovering heavy hydrocarbons from a subsurface formation, the system comprising:
a geothermal well comprising:
a heat-receiving well section extending within a geothermal zone of the formation and being configured to be heated by geothermal heat in the geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least a heavy hydrocarbon zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the heavy hydrocarbon zone to promote mobilization of the heavy hydrocarbons;
and a production well located in the heavy hydrocarbon zone and configured to receive mobilized heavy hydrocarbons for recovery to surface.

2. The system of claim 1, wherein the heavy hydrocarbons comprise heavy oil or bitumen.

3. The system of claim 1 or 2, wherein the geothermal well comprises an elongated component located in a corresponding wellbore and composed of a heat conductive material, and the heat is transmitted upward from the heat-receiving well section by conduction.

4. The system of any one of claims 1 to 3, wherein the geothermal well comprises an insulated casing.

5. The system of claim 4, wherein the insulated casing is a vacuum insulated tubing casing.

6. The system of any one of claims 1 to 5, wherein the geothermal well further comprises an upper well section that extends from the heat-transmission well section to the surface.

Date Recue/Date Received 2021-10-08

7. The system of claim 6, wherein the geothermal well is configured to receive an injection fluid that is injectable downhole from the surface via the upper well section, and enters the heavy hydrocarbon zone via the heat-transmission well section.

8. The system of claim 7, wherein the geothermal well is configured so that the injection fluid is heated in the heat-transmission section to form a heated fluid, and the heated fluid is injected into the heavy hydrocarbon zone via the heat-transmission well section.

9. The system of claim 7 or 8, wherein the injection fluid is not preheated at the surface.

10. The system of any one of claims 7 to 9, wherein the injection fluid comprises a gas, a liquid, or a mixture thereof.

11. The system of claim 10, wherein the gas comprises steam or CO2.

12. The system of claim 10, wherein the liquid comprises water.

13. The system of claim 12, wherein the geothermal well is configured such that steam is generated upon heating of the water in the heat-transmission well section, and the steam is injected into the heavy hydrocarbon zone from the heat-transmission well section.

14. The system of any one of claims 7 to 13, wherein the heat-transmission well section comprises a tubular liner comprising perforations for injection of the injection fluid into the heavy hydrocarbon zone.

15. The system of any one of claims 7 to 14, wherein the geothermal well comprises at least one valve or packer located in a downhole region of the heat-transmission well section to prevent flow of the injection fluid further downhole.

16. The system of claim 15, wherein the at least one valve or packer is located at a downhole end of the heat-transmission well section to prevent flow of the injection fluid into the heat-receiving well section.
Date Recue/Date Received 2021-10-08

17. The system of any one of claims 7 to 16, wherein the geothermal well comprises at least one control valve located at an uphole region of the heat-transmission well section or in the upper well section to control the injection fluid entering the heat-transmission well section.

18. The system of any one of claims 1 to 17, wherein the heat-receiving well section is configured to receive a hot native fluid from the geothermal zone of the formation, and transport the hot native fluid uphole into the heat-transmitting well section.

19. The system of claim 18, wherein the hot native fluid is injected into the heavy hydrocarbon zone via the heat-transmission well section.

20. The system of claims 18 or 19, wherein the hot native fluid comprises a gas, a liquid, or a mixture thereof.

21. The system of claim 20, wherein the gas comprises steam or CO2.

22. The system of claim 20, wherein the liquid comprises water.

23. The system of claim 22, wherein the geothermal well is configured such that lower pressures that are present ascending up the geothermal well cause the water to flash to form steam which is injected into the heavy hydrocarbon zone via the heat-transmission well section.

24. The system of any one of claims 18 to 23, wherein the geothermal well comprises at least one stop valve or packer located in an uphole region of the heat-receiving well section to prevent flow of the native fluid further up the geothermal well.

25. The system of claim 24, wherein the geothermal well comprises a flow control valve that is located at an uphole region of the heat-receiving well section and configured to control flow of the hot native fluid into the heat-transmission well section.

26. The system of claim 25, wherein the at least one flow control valve controls the amount of the native fluid entering the heat-transmission well section.

27. The system of any one of claims 1 to 6, wherein the heat-receiving well section is configured to transmit the heat by conduction to the heat-transmission well section, and the heat-Date Recue/Date Received 2021-10-08 transmission well section is configured to transmit the heat into the heavy hydrocarbon zone by conduction, in the absence of fluid injection into the heavy hydrocarbon zone.

28. The system of claim 27, wherein the heat-receiving well section is configured to prevent flow of a native fluid from the geothermal zone of the formation uphole into the heat-transmission well section.

29. The system of any one of claims 1 to 28, wherein the heat-transmission well section is horizontal and overlies at least a portion of the production well.

30. The system of any one of claims 1 to 28, wherein the heat-transmission well section is parallel with and vertically spaced apart from the production well.

31. The system of any one of claims 1 to 28, wherein the heat-receiving well section is substantially perpendicular with respect to the heat-transmission well section.

32. The system of any one of claims 1 to 28, wherein the heat-receiving well section is generally vertical.

33. The system of any one of claims 1 to 28, wherein the heat-receiving well section is generally inclined.

34. The system of any one of claims 1 to 33, wherein the heavy hydrocarbon zone and the geothermal zone are vertically separated from each other by at least one barrier zone of the formation.

35. The system of any one of claims 1 to 34, wherein the heat-receiving well section has branched well sections or is a linear well section.

36. The system of any one of claims 1 to 35, wherein there are a plurality of the geothermal wells associated with one or more production wells.

37. The system of any one of claims 1 to 36, wherein a plurality of the production wells is associated with the geothermal well.

Date Recue/Date Received 2021-10-08

38. A method for recovering heavy hydrocarbons from a subsurface fomiation, the method comprising:
heating a heavy hydrocarbon zone of the formation and mobilizing heavy hydrocarbons contained therein with geothermal heat obtained from a geothermal zone of the formation, wherein the geothermal heat is obtained by a geothermal well comprising:
a heat-receiving well section extending within the geothermal zone of the formation, and being configured to be heated by geothermal heat in the lower geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least the heavy hydrocarbon zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the heavy hydrocarbon zone to promote mobilization of the heavy hydrocarbons; and recovering the mobilized heavy hydrocarbons to surface.

39. The method of claim 38, wherein the heating and the recovering are performed simultaneously;
or wherein the heating is performed as a pretreatment step prior to recovering the mobilized heavy hydrocarbons from the subsurface formation.

40. The method of claim 38 or 39, wherein the heating of the heavy hydrocarbon zone is performed by conduction of the geothermal heat through the heat-receiving well section and the heat-transmission well section and into the heavy hydrocarbon zone in the absence of fluid injection into the geothermal well.

41. The method of claim 38 or 39, wherein the heating of the heavy hydrocarbon zone is performed by conduction of the geothermal heat from the heat-receiving well section to the heat-transmission well section, and by downhole injection of an injection fluid that is heated in the heat-transmission well section and then injected into the heavy hydrocarbon zone.

42. The method of claim 38 or 39, wherein the heating of the heavy hydrocarbon zone comprises introducing a circulation fluid downhole into the geothermal well, wherein the circulation fluid Date Recue/Date Received 2021-10-08 is circulated through the heat-receiving well section to be heated to form a heated fluid, and then the heated fluid is transported to the heat-transmission well section for injection into the heavy hydrocarbon zone or for indirect heating of the heavy hydrocarbon zone.

43. The method of claim 41 or 42, wherein the circulation fluid comprises a gas, a liquid, or a mixture thereof.

44. The method of claim 43, wherein the gas comprises steam or CO2.

45. The method of claim 43, wherein the liquid comprises water.

46. The method of claim 45, wherein steam is generated as the heated fluid upon heating of the water in the heat-receiving well section, and the steam is injected into the heavy hydrocarbon zone from the heat-transmission well section.

47. The method of claim 38 or 39, wherein the heating of the heavy hydrocarbon zone is performed by conduction of the geothermal heat from the heat-receiving well section to the heat-transmission well section, and by injection of a hot native fluid that is received from the geothemial zone of the formation through heat-receiving well section, transported uphole to the heat-transmission well section, and then injected into the heavy hydrocarbon zone.

48. The method of claim 47, wherein the native fluid comprises a gas, a liquid, or a mixture thereof.

49. The method of claim 48, wherein the gas comprises steam or CO2.

50. The method of claim 49, wherein the liquid comprises water.

51. The method of claim 50, wherein lower pressures that are present ascending up the geothermal well cause the water to flash to form steam which is injected into the heavy hydrocarbon zone via the heat-transmission well section.

52. The method of any one of claims 38 to 51, wherein the recovering of the mobilized heavy hydrocarbons is perfomied by gravity drainage.

53. A method for recovering hydrocarbons from a subsurface fomiation, the method comprising transferring geothemial heat from a geothemial zone of the formation to a hydrocarbon zone Date Recue/Date Received 2021-10-08 located above the geothermal zone by conduction to promote mobilization of the hydrocarbons for production thereof to surface.

54. A method for recovering hydrocarbons from a subsurface fomiation, the method comprising transferring geothermal heat from a geothermal zone of the formation to a hydrocarbon zone located above the geothermal zone without transferring the geothermal heat to surface to promote mobilization of the hydrocarbons for production thereof to the surface.

55. The method of claim 53 or 54, wherein the hydrocarbons are heavy hydrocarbons.

56. A method for heating and recovering a fluid in a subsurface formation, the method comprising:
heating a fluid-containing zone of the formation with geothermal heat obtained from a geothermal zone of the formation, wherein the geothermal heat is obtained by a geothermal well comprising:
a heat-receiving well section extending within the geothermal zone of the formation, and being configured to be heated by geothermal heat in the lower geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least the fluid-containing zone of the formation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the fluid-containing zone to heat fluids contained therein; and recovering heated fluid to surface.

57. A system for recovering hydrocarbons from a subsurface formation, the system comprising:
a geothermal well comprising:
Date Recue/Date Received 2021-10-08 a heat-receiving well section extending within a geothermal zone of the formation and being configured to be heated by geothermal heat in the geothemial zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least a hydrocarbon zone of the fomiation located above the geothermal zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the hydrocarbon zone to promote mobilization of the hydrocarbons; and a production well located in the hydrocarbon zone and configured to receive mobilized hydrocarbons for recovery to surface.

58. A method for recovering hydrocarbons from a subsurface fomiation, the method comprising:
heating a hydrocarbon zone of the formation and mobilizing hydrocarbons contained therein with geothermal heat obtained from a geothermal zone of the formation, wherein the geothermal heat is obtained by a geothermal well comprising:
a heat-receiving well section extending within the geothermal zone of the formation, and being configured to be heated by geothermal heat in the lower geothermal zone and transmit heat upward;
a heat-transmission well section extending from the heat-receiving well section and extending into at least the hydrocarbon zone of the formation located above the geothemial zone, the heat-transmission well section being configured to receive heat from the heat-receiving well section and transmit heat into the hydrocarbon zone to promote mobilization of the hydrocarbons; and recovering the mobilized hydrocarbons to surface.

Date Recue/Date Received 2021-10-08