PROCESSES FOR PRODUCING HYDROCARBONS FROM A RESERVOIR

PROCEDE DE PRODUCTION D'HYDROCARBURES A PARTIR D'UN RESERVOIR

English Abstract

In one aspect, there is provided a process for producing hydrocarbons from a reservoir, comprising: within the reservoir, electrically heating a liquid heating fluid such that the liquid heating fluid is evaporated to produce a gaseous heating fluid that heats the liquid hydrocarbon material within the reservoir such that the heated liquid hydrocarbon material is mobilized and such that the gaseous heating fluid is condensed to produce a condensed heating fluid, wherein the liquid heating fluid includes at least a fraction of the condensed heating fluid such that at least a fraction of the condensed heating fluid is refluxed; and producing a fluid including the mobilized hydrocarbon material; wherein the hydrocarbon reservoir is spaced apart from the earth's surface by a minimum distance of less than 75 metres.

French Abstract

Selon un aspect, un procédé de production dhydrocarbures dans un réservoir comprend : dans le réservoir, le chauffage électrique dun liquide chauffant de manière à ce que le liquide chauffant sévapore pour produire un gaz chauffant le matériau dhydrocarbure liquide dans le réservoir, de sorte que le matériau dhydrocarbure liquide chauffé est mobilisé et le gaz chauffant est condensé afin de produire un fluide chauffant condensé, le liquide chauffant comprenant au moins une fraction du fluide chauffant condensé, de sorte quau moins une fraction du fluide chauffant condensé est reflué; la production dun fluide comprenant le matériau dhydrocarbure mobilisé, le réservoir dhydrocarbures étant espacé de la surface terrestre dune distance minimale de moins de 75 m.

Claims

CLAIMS
What is claimed is:
1. A
process for producing hydrocarbon material from a hydrocarbon reservoir
comprising
a high pressure phrase and a low pressure phase, wherein the low pressure
phase follows the
high pressure phase;
wherein:
the low pressure phase includes, while the reservoir is disposed below a
predetermined
low pressure:
within the reservoir containing a production well and a non-production well
disposed above the production well, electrically heating a liquid heating
fluid such that
the liquid heating fluid is evaporated to produce a gaseous heating fluid that
heats the
liquid hydrocarbon material within the reservoir such that the heated liquid
hydrocarbon
material is mobilized and such that the gaseous heating fluid is condensed to
produce a
condensed heating fluid, wherein the liquid heating fluid being evaporated
includes at
least a fraction of the condensed heating fluid such that at least a fraction
of the
condensed heating fluid is refluxed;
during at least a fraction of the duration of the low pressure phase,
supplying
supplemental liquid heating fluid to the reservoir from a source at the
surface, such that
the liquid heating fluid being evaporated includes the supplemental liquid
heating fluid;
and
producing a production fluid including the mobilized hydrocarbon material from

the production well;
and
the high pressure phase includes, while the reservoir is disposed above a
predetermined
high pressure:
within the reservoir containing a production well and a non-production well
disposed above the production well, electrically heating a liquid heating
fluid such that
the liquid heating fluid is evaporated to produce a gaseous heating fluid that
heats the
liquid hydrocarbon material within the reservoir such that the heated liquid
hydrocarbon
material is mobilized and such that the gaseous heating fluid is condensed to
produce a
condensed heating fluid, wherein the liquid heating fluid being evaporated
includes at
43

least a fraction of the condensed heating fluid such that at least a fraction
of the
condensed heating fluid is refluxed;
during at least a fraction of the duration of the high pressure phase,
supplying
supplemental liquid heating fluid to the reservoir from a source at the
surface, such that
the liquid heating fluid being evaporated includes the supplemental liquid
heating fluid;
and
producing a production fluid. including the mobilized hydrocarbon material
from the
production well.
2. The process as claimed in claim 1:
wherein, during the low pressure phase, the predetermined low pressure is less
than 1500 kPa.
3. The process as claimed in any one of claims 1 to 2:
wherein, during the low pressure phase, the predetermined low pressure is less
than 1000 kPa.
4. The process as claimed in any one of claims 1 to 3:
wherein, during the high pressure phase, the predetermined high pressure is
greater than 1750
kPa.
5. The process as claimed in any one of claims 1 to 4:
wherein, during the high pressure phase, the predetermined high pressure is
greater than 2000
kPa.
6. The process as claimed in any one of claims 1 to 5;
wherein the ratio of the predetermined high pressure to the predetermined low
pressure is
greater than 1.5.
7. The process as claimed in any one of claims 1 to 5;
wherein the ratio of the predetermined high pressure to the predetermined low
pressure is
greater than 2.
8. The process as claimed in any one of claims 1 to 5;
wherein the ratio of the predetermined high pressure to the predetermined low
pressure is
greater than 3.
9. The process as claimed in any one of claims 1 to 8;
44

wherein the duration of the low pressure phase is at least one (1) month.
10. The process as claimed in any one of claims 1 to 9;
wherein the duration of the high pressure phase is at least one (1) month.
11. The process as claimed in any one of claims 1 to 10;
wherein the high pressure phase and the low pressure phase define a cycle, and
the cycle is
repeated at least once.
12. The process as claimed in any one of claims 1 to 10;
wherein the high pressure phase and the low pressure phase define a cycle, and
the cycle is
repeated at least twice.
13. The process as claimed in any one of claims 1 to 12, further
comprising:
during a fraction of the duration of the low pressure phase, suspending the
producing of the
production fluid.
14. The process as claimed in any one of claims 1 to 13, further
comprising:
during a fraction of the duration of the high pressure phase, suspending the
producing of the
production fluid.
15. The process as claimed in any one of claims 1 to 13, further
comprising:
during a fraction of the duration of the low pressure phase, suspending the
producing of the
production fluid. and
during at least a fraction of the time period while the producing is
suspended, supplying
supplemental liquid heating fluid to the reservoir from a source at the
surface, such that the
liquid heating fluid being evaporated includes the supplemental liquid heating
fluid.
16. The process as claimed in any one of claims 1 to 12 and 15, further
comprising:
during a fraction of the duration of the high pressure phase, suspending the
producing of the
production fluid, and
during at least a fraction of the time period while the producing is
suspended, supplying
supplemental liquid heating fluid to the reservoir from a source at the
surface, such that the
liquid heating fluid being evaporated includes the supplemental liquid heating
fluid.
17. The process as claim in any one of claims 1-16, wherein the
supplemental liquid heating
fluid comprises at least one of a solvent or water.

18. The process as claimed in any one of claims 1-17, wherein the
electrically heating is
provided by indirect heat transfer communication with the reservoir fluid via
a liquid heat transfer
medium.
19. The process as claimed in claim 18, wherein the liquid heat transfer
medium is glycerin.
20. The process as claimed in any one of claims 1-19, further comprising:
disposing the produced reservoir fluid in indirect heat exchange communication
with a
second heat transfer fluid to indirectly transfer heat to the second heat
transfer fluid such that
the second heat transfer fluid is evaporated; and
communicating the evaporated second heat transfer fluid to a turbine for
generating
electricity.
21. The process as claim in any one of claims 1-20, wherein the non-
production and
production wells are spaced apart by 5 metres or more.
22. The process as claimed in claim 21, wherein the non-production and
production wells
are spaced apart by 10 metres.
23. The process as claimed in any one of claims 1-22, further comprising a
start-up phase
preceeding the high pressure phase and the low pressure phase, the start-up
phase comprising:
heating the liquid hydrocarbon material within the reservoir with heat from an
electric heater, the
heat provided to the liquid hydrocarbon material by conduction, convention, or
a combination of
conduction and convention, such that the heated liquid hydrocarbon material is
mobilized.
24. The process as claimed in any one of claims 1-23, wherein electrically
heating the liquid
heating fluid occurs at least in the non-production well.
46

Description

PROCESSES FOR PRODUCING HYDROCARBONS FROM A RESERVOIR
FIELD
[0001] The present disclosures relates to improvements in production of
hydrocarbon
material from hydrocarbon-bearing reservoirs.
BACKGROUND
[0002] Thermal enhanced oil recovery methods are used to recover bitumen
and heavy oil
from hydrocarbon reservoirs. Petroleum reservoirs contain solid matrix, oil
and water and all
thermal recovery processes used for heavy oil recovery employ heat to raise
the temperature of
the oils to reduce their viscosity. In the process, all of the materials
present in the reservoir must
be heated in order to achieve heating of the oil. In the present disclosure,
the water present in
the formation is used as the primary heat transfer medium, supplemented with a
minimal
amount of injected fluid. The most dominant of the thermal recovery methods is
steam-assisted
gravity drainage ("SAGD"). SAGD operations are impaired by energy losses and
hydraulic
pressure losses suffered by fluids being conducted through the injection and
production wells.
As well, SAGD operations are particularly susceptible to fluid incursions from
active water
zones, which may disrupt the SAGD process. The SAGD process also suffers from
high capital
and operating costs making SAGD project economics marginal and susceptible to
changes in
commodity price. SAGD involves the use of large amounts of water and consumes
significant
quantities of fuel for steam generation causing large carbon dioxide
emissions.
SUMMARY
[0003] In one aspect, there is provided a process for producing
hydrocarbons from a
reservoir, comprising: within the reservoir, electrically heating a liquid
heating fluid such that the
liquid heating fluid is evaporated to produce a gaseous heating fluid that
heats the liquid
hydrocarbon material within the reservoir such that the heated liquid
hydrocarbon material is
mobilized and such that the gaseous heating fluid is condensed to produce a
condensed
heating fluid, wherein the liquid heating fluid includes at least a fraction
of the condensed
heating fluid such that at least a fraction of the condensed heating fluid is
refluxed; and
1
CA 2929924 2017-08-24

producing a fluid including the mobilized hydrocarbon material; wherein the
hydrocarbon
reservoir is spaced below the earth's surface by a distance of less than 75
metres.
[0004]
In another aspect, there is provided a process for producing hydrocarbon
material
from a hydrocarbon reservoir comprising: within the reservoir, electrically
heating a liquid
heating fluid such that the liquid heating fluid is evaporated to produce a
gaseous heating fluid;
heating hydrocarbon material with the gaseous heating fluid such that the
heated hydrocarbon
material is mobilized and such that the gaseous heating fluid is condensed to
produce a
condensed heating fluid; wherein the liquid heating fluid includes at least a
fraction of the
condensed heating fluid such that at least a fraction of the condensed heating
fluid is refluxed;
and producing a produced fluid including at least the mobilized hydrocarbon
material; wherein
the hydrocarbon reservoir is spaced below the earth's surface by a distance of
less than 75
metres.
[0005]
In another aspect, there is provided a process for producing hydrocarbon
material
from a hydrocarbon reservoir comprising a high pressure phrase and a low
pressure phase,
wherein the low pressure phase follows the high pressure phase;
wherein:
the low pressure phase includes, while the reservoir is disposed below a
predetermined
low pressure:
within the reservoir, electrically heating a liquid heating fluid such that
the liquid
heating fluid is evaporated to produce a gaseous heating fluid that heats the
liquid
hydrocarbon material within the reservoir such that the heated liquid
hydrocarbon
material is mobilized and such that the gaseous heating fluid is condensed to
produce a
condensed heating fluid, wherein the liquid heating fluid being evaporated
includes at
least a fraction of the condensed heating fluid such that at least a fraction
of the
condensed heating fluid is refluxed; and
producing a production fluid including the mobilized hydrocarbon material;
and
the high pressure phase includes, while the reservoir is disposed above a
predetermined
high pressure:
within the reservoir, electrically heating a liquid heating fluid such that
the liquid
heating fluid is evaporated to produce a gaseous heating fluid that heats the
liquid
2
CA 2929924 2017-08-24

hydrocarbon material within the reservoir such that the heated liquid
hydrocarbon
material is mobilized and such that the gaseous heating fluid is condensed to
produce a
condensed heating fluid, wherein the liquid heating fluid being evaporated
includes at
least a fraction of the condensed heating fluid such that at least a fraction
of the
condensed heating fluid is refluxed; and
producing a production fluid including the mobilized hydrocarbon material.
[0006] In another aspect, there is provided
A process for producing hydrocarbon material from a hydrocarbon reservoir
comprisinga high
pressure phrase of the process and a low pressure phase of the process,
wherein the low
pressure phase follows the high pressure phase;
wherein:
the low pressure phase includes, while the reservoir is disposed below a
predetermined
low pressure:
within the reservoir, electrically heating a liquid heating fluid such that
the liquid
heating fluid is evaporated to produce a gaseous heating fluid;
heating hydrocarbon material with the gaseous heating fluid such that the
heated
hydrocarbon material is mobilized and such that the gaseous heating fluid is
condensed to
produce a condensed heating fluid;
wherein the liquid heating fluid being evaporated includes at least a fraction
of
the condensed heating fluid such that at least a fraction of the condensed
heating fluid is
refluxed; and
producing a production fluid including at least the mobilized hydrocarbon
material;
and
the high pressure phase includes, while the reservoir is disposed above a
predetermined
high pressure:
within the reservoir, electrically heating a liquid heating fluid such that
the liquid
heating fluid is evaporated to produce a gaseous heating fluid;
3
CA 2929924 2017-08-24

heating hydrocarbon material with the gaseous heating fluid such that the
heated
hydrocarbon material is mobilized and such that the gaseous heating fluid is
condensed to
produce a condensed heating fluid;
wherein the liquid heating fluid being evaporated includes at least a fraction
of
the condensed heating fluid such that at least a fraction of the condensed
heating fluid is
refluxed; and
producing a production fluid including at least the mobilized hydrocarbon
material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In the drawings, embodiments of the invention are illustrated by way
of example. It is
to be expressly understood that the description and drawings are only for the
purpose of
illustration and as an aid to understanding, and are not intended as a
definition of the limits of
the invention.
[0008] Embodiments will now be described, by way of example only, with
reference to the
attached figures, wherein:
[0009] Figure 1 is a schematic illustration of a system, with a single
well, used to implement
an embodiment of the process;
[0010] Figure 2 is a schematic illustration of a system, with a non-
production well and a
production well, used to implement an embodiment of the process; and
[0011] Figure 3 is a sectional elevation view of a heating assembly of a
system used to
implement an embodiment of the process.
DETAILED DESCRIPTION
[0012] There is provided a process for producing liquid hydrocarbon
material from a
hydrocarbon reservoir 1000. Liquid hydrocarbon material is liquid material
that consists of a
least one hydrocarbon compound.
[0013] In some embodiments, for example, the liquid hydrocarbon material
includes
bitumen. In some of these embodiments, for example, the bitumen is a liquid
hydrocarbon
material with an API gravity less than, or equal to, 10, and with an in situ
viscosity of greater
than 10,000 centipoise. In some embodiments, for example, the liquid
hydrocarbon material
includes heavy oil.
4
CA 2929924 2017-08-24

[0014] In some embodiments, for example, the hydrocarbon reservoir 1000
is an oil sands
reservoir. In some embodiments, for example, the hydrocarbon reservoir is a
heavy oil
reservoir. In some embodiments, for example, the hydrocarbon reservoir is
disposed subsea.
[0015] In some embodiments, for example, the process includes:
within the reservoir 1000, electrically heating a liquid heating fluid such
that the liquid heating
fluid is evaporated to produce a gaseous heating fluid that heats the liquid
hydrocarbon material
within the reservoir such that the heated liquid hydrocarbon material is
mobilized and such that
the gaseous heating fluid is condensed to produce a condensed heating fluid,
wherein the liquid
heating fluid includes at least a fraction of the condensed heating fluid such
that at least a
fraction of the condensed heating fluid is refluxed;
producing a fluid including the mobilized hydrocarbon material.
[0016] In some embodiments, for example, the process includes:
within the reservoir 1000, electrically heating a liquid heating fluid such
that the liquid
heating fluid is evaporated to produce a gaseous heating fluid;
heating hydrocarbon material with the gaseous heating fluid such that the
heated
hydrocarbon material is mobilized and such that the gaseous heating fluid is
condensed to
produce a condensed heating fluid;
wherein the liquid heating fluid includes at least a fraction of the condensed
heating
fluid such that at least a fraction of the condensed heating fluid is
refluxed;
producing a produced fluid including at least the mobilized hydrocarbon
material.
[0017] In some embodiments, for example, the produced fluid may also
include some
heating fluid.
[0018] In some embodiments, for example, the liquid heating fluid is
comprised mainly of
the refluxing condensed heating fluid, and is, occasionally, supplemented by
additional liquid
heating fluid that is supplied downhole into the reservoir from a source of
liquid heating fluid
disposed at the surface.
[0019] In some embodiments, for example, the liquid heating fluid
includes formation water
that is resident within the hydrocarbon reservoir, or may include liquid
heating fluid (for example,
water) that is supplied into the hydrocarbon reservoir from a source at the
surface, or may
include both of the formation water and the injected heating fluid.
5
CA 2929924 2017-08-24

[0020]
By refluxing the liquid heating fluid within the reservoir, heat losses are
avoided,
when compared to conducting a heating fluid, such as steam, from the surface
and into the
reservoir, such as during a steam-assisted gravity drainage ("SAGD) operation.
Heat losses are
attributable to the production of the condensed heating fluid (i.e. steam
condensate) along with
the heated and mobilized bitumen through the production well to the surface.
The steam
condensate is at or near saturated steam temperature as it is produced into
the well, and heat
losses occur as the produced fluid are conducted from the reservoir to the
surface facilities. In
the process of separating the oil from the water at the surface, additional
heat is lost. In many
SAGD operations, the produced water is further cooled to allow for treatment
to render it
suitable for recycling as boiler feedwater. Thus, if the water is "refluxed"
within the reservoir,
instead of being produced, the heat losses associated with the production and
recycling of
produced water are avoided.
[0021]
In those embodiments where at least a fraction of the liquid heating fluid
is being
supplied from above the surface, in some of these embodiments, for example,
the ratio of the
volumetric rate at which the supplied liquid heating fluid is being supplied
to the rate at which
heat energy is being delivered by the electric heater is less than 25 cubic
metres per day per
megawatt, such as, for example, less than 10 cubic metres per day per
megawatt.
[0022]
In some embodiments, for example, the liquid heating fluid includes water,
such that,
upon evaporation, steam is produced. The steam is conducted to the hydrocarbon
material
within the reservoir, and heats the hydrocarbon material, thereby effecting
mobilization of the
hydrocarbon material, while also effecting the condensation of the steam.
In some
embodiments, for example, at least some of the condensed steam then drains
into a collection
reservoir, where it is re-evaporated by an electric heater disposed within the
collection reservoir.
[0023]
In some embodiments, for example, the liquid heating fluid may include any
combination of an anti-foaming chemical, a corrosion inhibitor, a scale
inhibitor, and solvent
material that is soluble within the hydrocarbon material. In some embodiments,
for example, the
solvent material includes at least one hydrocarbon compound, wherein the at
least one
hydrocarbon compound includes a total number of carbon atoms of between three
(3) and ten
(10), such as between five (5) and seven (7).
[0024] For oil sands formations, and where the liquid heating fluid, in the
evaporated state,
is steam, or is substantially steam, the cycle of evaporation, condensing and
re-evaporation
results in the creation of a steam chamber.
6
CA 2929924 2017-08-24

=
[0025] In some embodiments, for example, at least a fraction of the
reflux is effected by an
electric heater that is disposed within the hydrocarbon reservoir. In some
embodiments, for
example, electric heater includes an electrically resistive heater. In some
embodiments, for
example, the term "electric heater" covers heaters that effect electromagnetic
heating.
[0026] In some embodiments, for example, the electric heater is disposed in
indirect heat
transfer communication with at least a fraction of the condensed heating
fluid.
[0027] In some embodiments, for example, the electric heater is disposed
within a collection
reservoir, and the collection reservoir receives reservoir fluid from the
hydrocarbon reservoir.
The reservoir fluid includes the mobilized hydrocarbon material and condensed
heating fluid. In
some embodiments, for example, the collected reservoir fluid is free, or
substantially free, of the
liquid heating fluid. In this respect, the electrical heating by the electric
heater is such that the
collected reservoir fluid is free, or substantially free, of the liquid
heating fluid. In some
embodiments, for example, the collected reservoir fluid consists of, or
substantially consists of,
the mobilized hydrocarbon material. In this respect, the electrical heating by
the electric heater
is such that the collected reservoir fluid consists of, or substantially
consists of, the mobilized
hydrocarbon material. The collected reservoir fluid, consisting of, or
substantially consisting of,
the mobilized hydrocarbon material, is disposed in heat transfer fluid
communication with the
condensed heating fluid that is disposed externally of the collection
reservoir. In this respect,
upon heating by the electric heater, the collected reservoir fluid
concomitantly effects the
transfer of such heat imparted by the electric heater to the condensed heating
fluid, thereby
effecting evaporation of the condensed heating fluid. In some of these
embodiments, for
example, the heating of the collected reservoir fluid, consisting of, or
substantially consisting of,
the mobilized hydrocarbon material (and, in some embodiments, for example,
being free, or
substantially free of heating fluid), is such that the collected reservoir
fluid is disposed at a
temperature of less than 350 degrees Celsius, such as, for example, less than
300 degrees
Celsius, such as, for example, less than 275 degrees Celsius, such as, for
example less than
250 degrees Celsius.
[0028] Referring to Figure 1, in some embodiments, for example, the
process is effected
with a single well 102. In this respect, a system 100 is provided for
effecting the process, and
includes the well 102 which is used for both production of the produced fluid
as well as for
effecting the entirety of the reflux of the liquid heating fluid that is
effecting mobilization of the
hydrocarbon material (i.e. a second well is not being used to contain an
electric heater to effect
the refluxing).
7
CA 2929924 2017-08-24

,
[0029] The produced fluid is produced through the well 102. In some
embodiments, for
example, production is effected by artificial lift, such as by a downhole pump
(such as, for
example, an electric submersible pump) and/or by gas lift.
[0030] The well 102 extends into the hydrocarbon reservoir 1000 from
the surface. The well
102 includes a collection reservoir 108 for collecting reservoir fluids. The
reservoir fluids include
mobilized hydrocarbon material and condensed heating fluid. In some
embodiments, for
example, the reservoir fluid being collected within the well 102 is free, or
substantially free, of
heating fluid. In some embodiments, for example, the reservoir fluid being
collected within the
production well consists of, or substantially consists of, mobilized
hydrocarbon material Such
collected reservoir fluid 110 may be in heat transfer communication with the
condensed heating
fluid, such as, for example, condensed heating fluid that is disposed
externally of the production
well 102. In some embodiments, for example, the collected reservoir fluid 110
may include the
mobilized hydrocarbon material and condensed heating fluid.
[0031] An electric heater 104 is disposed within the well 102 and,
more specifically, within
the collection reservoir 108 of the well 102. The collection reservoir
includes reservoir fluid that
has collected therein. As mentioned above, the reservoir fluid includes
mobilized hydrocarbon
material, and may also include condensed heating fluid.
[0032] The electric heater 104 is configured for effecting heating of
the collected reservoir
fluid 110. In some embodiments, for example, the electric heater 104 is
disposed in direct heat
transfer communication with the collected reservoir fluid 110. Heating of any
condensed
heating fluid, whether disposed as part of the collected reservoir fluid 110,
or disposed in heat
transfer communication with the collected reservoir fluid 110, externally of
the well 102, is,
therefore, effected by the electric heater 104, when the electric heater is
heating the collected
reservoir fluid 110. In some embodiments, for example, the electrical heating
by the electric
heater 104 is such that the collected reservoir fluid consists is free, or
substantially free, of the
liquid heating fluid. In some embodiments, for example, the electrical heating
by the electric
heater is such that the collected reservoir fluid consists of, or
substantially consists of, the
mobilized hydrocarbon material, and, in this respect, is free, or
substantially free, of the liquid
heating fluid.
[0033] Referring to Figure 3, in some embodiments, for example, the
electric heater 104 is
part of a heating assembly 700, such that the electric heater is in indirect
heat transfer
communication with the reservoir fluid via a liquid heat transfer medium 704.
An example of a
suitable liquid heat transfer medium 704 is glycerin. In this respect, a
heating assembly 700 is
8
CA 2929924 2017-08-24

provided, and includes a housing 702, the electric heater, and the liquid heat
transfer medium
704. The electric heater is disposed within a housing 702, with the space
between the electric
heater and the housing 702 being occupied with the liquid heat transfer medium
704. The liquid
heat transfer medium 704 has a higher boiling point than that of the heating
fluid at the pressure
of the hydrocarbon reservoir portion from which the mobilized hydrocarbon
material is being
produced, such as by at least 10 degrees Celsius, such as, for example, by at
least 20 degrees
Celsius, such as, for example, by at least 50 degrees Celsius, such as, for
example, by at least
100 degrees Celsius. The collection reservoir 108 is defined by a space within
the production
well 102, between the housing 702 and the wellbore string (such as, for
example, casing) of the
.. production well. Because the heater assembly is disposed within the
collection reservoir, the
liquid heat transfer medium 704 is disposed in heat transfer communication
with the collected
reservoir fluid, through the wall of the housing 702. In this respect, heat is
transferred from the
electric heater to the collected reservoir fluid via the liquid heat transfer
medium 704 and
through the wall of the housing 702. By virtue of this configuration, any
evaporated heating fluid
may become disposed at a relatively higher temperature, owing to the fact that
the liquid heat
transfer medium 704 can be heated to higher temperatures by the electric
heater, and transfer
this higher quality heat to the reservoir fluids (and, therefore, to the
condensed heating fluid),
versus direct heating of the reservoir fluids by the electric heater (without
any intervening liquid
heat transfer medium 704). This also facilitates production of a "drier"
hydrocarbon material.
[0034] In some embodiments, for example, the electric heater 104 is
disposed within a
laterally extending section 102a of the well 102, that extends from a
vertically extending section
102b, at the heel 102c of the well 102. In some embodiments, for example, the
laterally
extending section 102a is disposed along a horizontal, or substantially
horizontal, axis.
[0035] In some embodiments, for example, the electric heater 104
includes a plurality of
heater segments, and each one of the heater segments may be controllable
independently from
the other heater segments in terms of the rate of energy being produced. By
providing a
plurality of heater segments that are independently controllable, improved
control of heating
fluid conformance is made possible.
[0036] In some embodiments, for example, the electrical heating provides
for more uniform
heating of the hydrocarbon reservoir versus heating of the hydrocarbon
reservoir with steam.
[0037] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 110 is such that the temperature of the collected reservoir fluid is
greater than or equal to at
least the boiling point of the liquid heating fluid at the pressure of the
hydrocarbon reservoir
9
CA 2929924 2017-08-24

portion from which the mobilized hydrocarbon material is being produced. In
this respect, both
of (i) evaporation of the heating fluid that is disposed in heat transfer
communication with the
collected reservoir fluid, but externally of the collection reservoir 108, and
(ii) evaporation of any
heating fluid that is present within the collected reservoir fluid, is
promoted, so as to return the
heating fluid to the reservoir for effecting mobilization of the hydrocarbon
material within the
reservoir 1000, and thereby contribute to the refluxing. As well, by promoting
the evaporation,
the produced fluid 118 contains less heating fluid, thereby reducing energy
requirements to
transport the produced fluid to the surface 1002 (as there is less fluid
volume to produce), and
also reducing demands on separation processes for removal of heating fluid
from the produced
fluids.
[0038] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 110 is effected in response to sensing of a temperature, of the
collected reservoir fluid,
that is at or below a predetermined temperature that is based upon the boiling
point of the liquid
heating fluid at the pressure of the hydrocarbon reservoir portion from which
the mobilized
hydrocarbon material is being produced. In some embodiments, prior to the
electrical heating of
the collected reservoir fluid, a temperature of the collected reservoir fluid
is sensed that is at or
below a predetermined temperature that is based upon the boiling point of the
liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. In some embodiments, for example, the
predetermined temperature
is at or above the boiling point of the liquid heating fluid at the pressure
of the hydrocarbon
reservoir portion from which the mobilized hydrocarbon material is being
produced. The
purpose of having the predetermined temperature being at the boiling point of
the liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced, is for evaporating liquid heating fluid that has
collected within the
well. Liquid heating fluid that has collected within the well would be
disposed at or below the
boiling point of the liquid heating fluid at the pressure of the hydrocarbon
reservoir portion from
which the mobilized hydrocarbon material is being produced (where the heating
fluid, in the
liquid state, is water, this would be the saturated steam temperature within
the reservoir). By
effecting electrical heating while the collected reservoir fluid is disposed
at or below the boiling
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, the intention is to
vaporize the liquid
heating fluid that has collected within the well as part of the collected
reservoir fluid. In some
embodiments, for example, it may be intended to vaporize the heating fluid
that is disposed
externally of the well 102, in which case the predetermined temperature may be
above the
CA 2929924 2017-08-24

boiling point of the liquid heating fluid at the pressure of the hydrocarbon
reservoir portion from
which the mobilized hydrocarbon material is being produced, for purposes of
precluding
collection of the heating fluid within the well 102.
[0039] In some embodiments, for example, the well 102 includes the heel
102c. In this
.. respect, the electrical heating of the collected reservoir fluid by the
electric heater 104 is such
that the temperature of the collected reservoir fluid, disposed at the heel
102c of the production
well 102, is greater than or equal to the boiling point of the liquid heating
fluid at the pressure of
the hydrocarbon reservoir portion from which the mobilized hydrocarbon
material is being
produced. Similar to the above, both of (i) evaporation of the heating fluid
that is disposed in
heat transfer communication with the collected reservoir fluid, but externally
of the collection
reservoir, and (ii) evaporation of any heating fluid that is present within
the collected reservoir
fluid, is promoted, so as to return the heating fluid to the reservoir for
effecting mobilization of
the hydrocarbon material within the reservoir, and thereby contribute to the
refluxing. As well,
by promoting the evaporation, the produced fluid that is being produced
contains less heating
fluid, thereby reducing energy requirements to transport the produced fluid to
the surface (as
there is less fluid volume to produce), and also reducing demands on
separation processes for
removal of heating fluid from the produced fluids.
[0040] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 110 by the electric heater 104 is effected in response to sensing of a
temperature, of the
collected reservoir fluid 110 disposed at the heel 102c of the well 102, that
is at or below a
predetermined temperature that is based upon the boiling point of the liquid
heating fluid at the
pressure of the hydrocarbon reservoir portion from which the mobilized
hydrocarbon material is
being produced. In some embodiments, for example, prior to the electrical
heating of the
collected reservoir fluid 110 by the electric heater 104, a temperature, of
the collected reservoir
fluid that is disposed at the heel 102c of the well 102, is sensed that is at
or below a
predetermined temperature that is based upon the boiling point of the liquid
heating fluid at the
pressure of the hydrocarbon reservoir portion from which the mobilized
hydrocarbon material is
being produced. In some embodiments, for example, the predetermined
temperature is at or
above the boiling point of the liquid heating fluid at the pressure of the
hydrocarbon reservoir
portion from which the mobilized hydrocarbon material is being produced. The
purpose of
having the predetermined temperature being at the boiling point of the liquid
heating fluid at the
pressure of the hydrocarbon reservoir portion from which the mobilized
hydrocarbon material is
being produced, is for evaporating liquid heating fluid that has collected
within the well. Liquid
11
CA 2929924 2017-08-24

heating fluid that has collected within the well would be disposed at or below
the boiling point of
the liquid heating fluid at the pressure of the hydrocarbon reservoir portion
from which the
mobilized hydrocarbon material is being produced (where the heating fluid, in
the liquid state, is
water, this would be the saturated steam temperature within the reservoir). By
effecting
.. electrical heating while the collected reservoir fluid is disposed at or
below the boiling point of
the liquid heating fluid at the pressure of the hydrocarbon reservoir portion
from which the
mobilized hydrocarbon material is being produced, the intention is to vaporize
the liquid heating
fluid that has collected within the well as part of the collected reservoir
fluid. In some
embodiments, for example, it may be intended to vaporize the heating fluid
that is disposed
externally of the well, in which case the predetermined temperature may be
above the boiling
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, for purposes of
precluding collection of
the heating fluid within the well.
[0041] In some embodiments, for example, during a first time interval,
the collected
reservoir fluid 110, within the well 102, is not being produced (such as, for
example, when the
production of the collected reservoir fluid is suspended), liquid heating
fluid is being supplied to
the hydrocarbon reservoir via the well 102, and the electrical heating is such
that the liquid
heating fluid is evaporated and such that the hydrocarbon reservoir
surrounding the well 102
becomes disposed above a predetermined temperature that is above the boiling
point of the
liquid heating fluid at the pressure of the hydrocarbon reservoir portion from
which the mobilized
hydrocarbon material is being produced (such as, for example, above 350
degrees Celsius).
Both of the supplying of the liquid heating fluid and the electrical heating
is then suspended.
Subsequently, during a second time interval, and while the rate at which heat
energy is being
delivered by the electric heater is less than 50% of the rate at which heat
energy is being
delivered by the electric heater during the first time interval, the collected
reservoir fluid 110 may
be produced. In some of these embodiments, for example, during the second time
interval, the
rate at which heat energy is being delivered by the electric heater is less
than 25% of the rate at
which heat energy is being delivered by the electric heater during the first
time interval. In some
of these embodiments, for example, during the second time interval, the
electrical heating by the
electrical heater is suspended.
[0042] During the first time interval, the electrical heating is such
that the hydrocarbon
reservoir surrounding the well 102 becomes dry, or substantially dry, in that
any heating fluid
within this portion of the hydrocarbon reservoir, has become evaporated, and
is being applied
12
CA 2929924 2017-08-24

,
to effect heating and mobilization of hydrocarbon material within the
reservoir. Further, in some
embodiments, for example, the electrical heating during the first time
interval may be sufficient
to effect heating of liquid heating fluid being supplied to the hydrocarbon
reservoir, via the well
102, to relatively high temperatures, including those which would otherwise
promote coking of
hydrocarbon material that is collected within collection reservoir of the well
102, so long as
collection of the mobilized hydrocarbon material within the collection
reservoir is avoided.
During the first time interval, draining of the mobilized hydrocarbon material
into the collection
reservoir may be precluded by the high pressure conditions existing at the
collection reservoir
owing to the evaporation of the liquid heating fluid.
During the second time interval, the
mobilized hydrocarbon material is draining and collecting within the well 102,
and is then
subsequently produced. The electrical heating of the hydrocarbon reservoir
during the first time
interval, in combination with any electrical heating of the hydrocarbon
reservoir during the
second time interval, is sufficient to maintain, during the second time
interval, the hydrocarbon
reservoir portion, that is surrounding the well 102, above the boiling point
of the liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. Because the temperature is so maintained, during
the second time
interval, condensed heating fluid may be re-evaporated, or substantially re-
evaporated, prior to
becoming disposed within the well 102, such that the collected reservoir fluid
110, which is
being produced, is free, or substantially free, of any heating fluid. As well,
because the
production is being effected, pressure within the hydrocarbon reservoir is
being reduced, such
that the heating fluid is more likely to remain in a vapour state, as opposed
to being condensed.
In some embodiments, for example, the collected reservoir fluid 110 being
collected within the
well 102, and which is being produced, consists of, or substantially consists
of, the mobilized
hydrocarbon material. In parallel, because the electrical heating is suspended
while the
collected reservoir fluid 110 is being so produced, coking of the collected
hydrocarbon material
is mitigated. In this respect, the process includes:
(a) during a first time interval, while supplying a liquid heating fluid to
the hydrocarbon
reservoir through a well 102, electrically heating, within the well 102, with
an electrical heater, a
combined heating fluid including the supplied liquid heating fluid and a
condensed heating fluid,
such that the combined heating fluid is evaporated to produce a gaseous
heating fluid that is
conducted into the reservoir and then condensed upon heating of hydrocarbon
material to
produce the condensed heating fluid;
(b) suspending the supplying of the liquid heating fluid;
13
CA 2929924 2017-08-24

,
(c) after the suspending, and during a second time interval, reducing the
rate at which
heat energy is being delivered by the electric heater such that the rate at
which heat energy is
being delivered by the electric heater is less than 50% of the rate at which
heat energy is being
delivered by the electric heater during the first time interval, and while the
electric heater is
delivering the heat energy at the reduced rate, collecting reservoir fluid
within the well 102, and
producing the collected reservoir fluid 110, wherein the collected reservoir
fluid 110 includes the
hydrocarbon material that has become mobilized and drained into the well 102;
and
(d) suspending of the producing.
[0043] The electrical heating of the hydrocarbon reservoir during the
first time interval, in
combination with any electrical heating of the hydrocarbon reservoir during
the second time
interval, is sufficient to, during the second time interval, effect
evaporation of condensed heating
fluid, that has condensed after effecting heating and mobilization of the
hydrocarbon material,
wherein the evaporation of the condensed heating fluid is effected prior to
the condensed
heating fluid being received by the well 102.
[0044] In some embodiments, for example, the electrical heating of the
hydrocarbon
reservoir during the first time interval, in combination with any electrical
heating of the
hydrocarbon reservoir during the second time interval, is sufficient to effect
evaporation of
condensed heating fluid that has condensed after effecting heating and
mobilization of the
hydrocarbon material, prior to the condensed heating fluid being received by
the well 102, such
that the collected reservoir fluid is free, or substantially free, of heating
fluid. In some
embodiments, for example, the collected reservoir fluid consists of, or
substantially consists of,
the mobilized hydrocarbon material.
[0045] In some of these embodiments, for example, during the second
time interval, the rate
at which heat energy is being delivered by the electric heater is less than
25% of the rate at
which heat energy is being delivered by the electric heater during the first
time interval. In some
of these embodiments, for example, during the second time interval, the
electrical heating by the
electrical heater is suspended.
[0046] In some embodiments, for example, the steps (a) to (d) are
repeated at least once,
such as, for example, at least twice, such as, for example, at least three (3)
times, such as, for
example, at least five (5) times. In this respect, in some embodiments, for
example, the process
is a cyclic process including steps (a) to (d), and the cyclic process is
repeated at least once,
14
CA 2929924 2017-08-24

such as, for example, at least twice, such as, for example, at least three (3)
times, such as, for
example, at least five (5) times.
[0047]
In some embodiments, for example, during a first time interval when the
collected
reservoir fluid, within the well 102, is not being produced (such as, for
example, when the
production of the collected reservoir fluid is suspended), the electrical
heating is such that the
hydrocarbon reservoir becomes disposed above a predetermined temperature that
is above the
boiling point of the liquid heating fluid at the pressure of the hydrocarbon
reservoir portion from
which the mobilized hydrocarbon material is being produced (such as, for
example, above 350
degrees Celsius). Subsequently, during a second time interval, the collected
reservoir fluid 110
may be produced, and during such production, the electrical heating of the
collected reservoir
fluid may be continued but modulated such that the collected reservoir fluid
110 is disposed
below 300 degrees Celsius, thereby mitigating coking of the collected
reservoir fluid 110. In
this respect, during the first time interval, the electrical heating is such
that the hydrocarbon
reservoir surrounding the well 102 becomes dry, or substantially dry, in that
any heating fluid
within this portion of the hydrocarbon reservoir, has become evaporated, and
is being applied
to effect heating and mobilization of hydrocarbon material within the
reservoir. Further, in some
embodiments, for example, the electrical heating during the first time
interval may be sufficient
to effect heating of liquid heating fluid being supplied to the hydrocarbon
reservoir, via the well
102, to relatively high temperatures, including those which would otherwise
promote coking of
hydrocarbon material that is collected within collection reservoir of the well
102, so long as
collection of the mobilized hydrocarbon material within the collection
reservoir is avoided.
During the first time interval, draining of the mobilized hydrocarbon material
into the collection
reservoir may be precluded by the high pressure conditions existing at the
collection reservoir
owing to the evaporation of the liquid heating fluid. During the second time
interval, reservoir
fluid, including the mobilized hydrocarbon material is draining and collecting
within the
production well 102, and is then subsequently produced. The electrical heating
during the first
time interval, in combination with any electrical heating during the second
time interval, is
sufficient to maintain, during the second time interval, the hydrocarbon
reservoir portion, that is
surrounding the well 102, above the boiling point of the liquid heating fluid
at the pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced.
Because the temperature is so maintained, condensed heating fluid is
evaporated prior to
becoming disposed within the well 102, such that the collected reservoir fluid
110 being
collected within the well 102, and which is being produced, is free, or
substantially free, of the
heating fluid.
As well, because the production is being effected, pressure within the
CA 2929924 2017-08-24

hydrocarbon reservoir is being reduced, such that the heating fluid is more
likely to remain in a
vapour state, as opposed to being condensed. In some embodiments, for example,
the
collected reservoir fluid 100 consists of, or substantially consists of, the
mobilized hydrocarbon
material. In parallel, because the electrical heating is modulated such that
such that the
collected reservoir fluid 110 is disposed below 350 degrees Celsius, as
described above, while
the collected reservoir fluid 110 is being so produced, coking of the
collected hydrocarbon
material is mitigated. In this respect, the process includes:
(a) during a first time interval, while supplying a liquid heating fluid to
the hydrocarbon
reservoir through a well 102, electrically heating, within the well 102, a
combined heating fluid
including the supplied liquid heating fluid and a condensed heating fluid,
such that the combined
heating fluid is evaporated to produce a gaseous heating fluid that is
conducted into the
reservoir, and then condensed upon heating of hydrocarbon material to produce
the condensed
heating fluid;
(b) suspending the supplying of the liquid heating fluid;
(c) after the suspending of the supplying of the liquid heating fluid,
during a second time
interval, modulating the electrical heating such that the electrical heating
of reservoir fluid
(including the mobilized hydrocarbon material, and, in some embodiments, for
example,
consisting, or substantially consisting of the mobilized hydrocarbon material)
that is being
collected within the well 102 is such that the temperature of the collected
reservoir fluid 110 is
less than 350 degrees Celsius (such as, for example, less than 350 degrees
Celsius, such as,
for example, less than 300 degrees Celsius, such as, for example, less than
250 degrees
Celsius, such as, for example, less than 220 degrees Celsius), and, while the
modulated
electrical heating of collected reservoir fluid is being effected, producing
the collected reservoir
fluid 110 from the well 102; and
(c) suspending the producing.
[0048] The electrical heating of the hydrocarbon reservoir during the
first time interval, in
combination with any electrical heating of the hydrocarbon reservoir during
the second time
interval, is sufficient to, during the second time interval, effect
evaporation of condensed heating
fluid, that has condensed after effecting heating and mobilization of the
hydrocarbon material,
prior to the condensed heating fluid being received by the well 102.
[0049] In some embodiments, for example, the electrical heating of the
hydrocarbon
reservoir during the first time interval, in combination with any electrical
heating of the
16
CA 2929924 2017-08-24

hydrocarbon reservoir during the second time interval, is sufficient to,
during the second time
interval, effect evaporation of condensed heating fluid, that has condensed
after effecting
heating and mobilization of the hydrocarbon material, prior to the condensed
heating fluid being
received by the well 102, such that the collected reservoir fluid 110 is free,
or substantially free,
of the heating fluid. In some embodiments, for example, the collected
reservoir fluid 110
consists of, or substantially consists of, the mobilized hydrocarbon material.
[0050] In some embodiments, for example, the modulating of the
electrical heating includes
suspending of the electrical heating.
[0051] In some embodiments, for example, the steps (a) to (d) are
repeated at least once,
such as, for example, at least twice, such as, for example, at least three (3)
times, such as, for
example, at least five (5) times. In this respect, in some embodiments, for
example, the process
is a cyclic process including steps (a) to (d), and the cyclic process is
repeated at least once,
such as, for example, at least twice, such as, for example, at least three (3)
times, such as, for
example, at least five (5) times.
[0052] In some embodiments, for example, during the first time interval,
the evaporated
combined heating fluid is superheated such that the temperature of the
hydrocarbon reservoir
becomes disposed above the boiling point of the liquid heating fluid at the
pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced.
In this respect, in some embodiments, for example, the predetermined
temperature is above
300 degrees Celsius, such as, for example, above 350 degrees Celsius, such as,
for example,
above 400 degrees Celsius.
[0053] By effecting heating of the hydrocarbon reservoir to above the
predetermined
temperature, the reservoir fluid, that is being collected within the well and
then produced, is free,
or substantially free, of the condensed heating fluid. In some embodiments,
for example,
consists of, or substantially consists of, the mobilized hydrocarbon material.
[0054] As discussed above, in some embodiments, for example, the
collected reservoir fluid
110 consists of, or substantially consists of, the mobilized hydrocarbon
material, and, in this
respect, is free, or substantially free, of the heating fluid. In those
embodiments where the
electric heater 104 is disposed in direct heat transfer communication with the
collected reservoir
fluid, by having the collected reservoir fluid consisting of, or substantially
consisting of, the
mobilized hydrocarbon material, evaporation of condensed heating fluid
disposed in heat
transfer communication with the collected reservoir fluid, may produce
evaporated heating fluid
17
CA 2929924 2017-08-24

,
having a relatively higher temperature, owing to the fact that the mobilized
hydrocarbon material
can be heated to higher temperatures by the electric heater, and transfer this
higher quality heat
to any condensed heating fluid disposed in heat transfer communication with
the collected
reservoir fluid, versus direct heating of the condensed heating fluid by the
electric heater
(without any intervening liquid heat transfer medium 704).
[0055] Also, by having the collected reservoir fluid 110 be free, or
substantially free, of the
heating fluid, scale formation within the production well 102 may be
mitigated. Where the
heating fluid, in its liquid state, includes water, it is preferable that
water does not become
disposed in contact structures within the production well, including the
electric heater 104, as
.. evaporation of water in this context may result in precipitation of
dissolved scale-forming solids
within the production well 102, including onto the electric heater or other
structures, resulting in
scale formation. This may be particularly relevant where the water includes
connate water (and
is, therefore, not possible to subject to pre-treatment for removal of scale-
forming solids), and is
most likely to occur during initial start-up. Accordingly, in such
embodiments, by ensuring that
the collected reservoir fluid is free, or substantially free, of the heating
fluid, the collected
heating fluid is fluidically isolated, or substantially fluidically isolated,
from the production well,
thereby mitigating potential scale formation within the production well
(including scale formation
on the electric heater).
[0056] Further, as a necessary incident, by having the collected
reservoir fluid 110 be free,
or substantially free, of the heating fluid, production of a "drier"
hydrocarbon material is
facilitated. This reduces energy requirements to transport the produced fluid
to the surface (as
there is less fluid volume to produce) and also reduces demands on separation
processes for
removal of heating fluid from the produced fluids.
[0057] In this respect, in some embodiments, for example, the rate of
heating of the
collected reservoir fluid 110 by the electric heater 104 is modulated such
that the collected
reservoir fluid is free, or substantially free, of the heating fluid. In some
embodiments, for
example, the rate of heating of the collected reservoir fluid 110 by the
electric heater 104 is
modulated such that the collected reservoir fluid consists of, or
substantially consists of, the
mobilized hydrocarbon material.
[0058] In some embodiments, for example, the composition of the collected
reservoir fluid
110 may be sensed by a densitometer. In this respect, the rate of heating
effected by the
electric heater 104 may be modulated based on sensing of the density of the
collected reservoir
fluid by the densitometer. In response to sensing of a density of the
collected reservoir fluid that
18
CA 2929924 2017-08-24

is characteristic of a collected reservoir fluid having excessive non-
hydrocarbon fluid (such as
the heating fluid), the rate of heating by the electric heater may be
increased to effect
evaporation of the fluid. This will promote the maintenance of a collected
reservoir fluid that
consists of hydrocarbon material, or substantially hydrocarbon material, and,
in this respect,
free, or substantially free, of the heating fluid. This promotes reflux of the
condensed heating
fluid (as above-described), higher quality heat transfer to effect the
evaporation of the
condensed heating fluid, mitigates scale formation, and production of "drier"
hydrocarbon
material.
[0059] Alternatively, the amount of water within the produced reservoir
fluid can be detected
.. by measuring electrical resistance of the produced reservoir fluid,
capacitance of the produced
reservoir fluid, or both of electrical resistance and capacitance of the
produced reservoir fluid,
and the rate of heating by the electric heater may be modulated in response to
this
measurement.
[0060] In some embodiments, for example, the electric heater 104 is
submerged within the
collected reservoir fluid 110 (in some embodiments, for example, free of,
substantially free of
the heating fluid, and in some embodiments, for example, consisting of
hydrocarbon material, or
substantially hydrocarbon material), and the producing is modulated such that
sufficient
collected reservoir fluid is maintained within the production well 102 such
that the electric heater
is submerged within collected reservoir fluid.
[0061] In those embodiments where the temperature of the collected
reservoir fluid is above
the boiling point of the liquid heating fluid at the pressure of the
hydrocarbon reservoir portion
from which the mobilized hydrocarbon material is being produced, the collected
reservoir fluid is
produced, such that the collected reservoir fluid is conducted to above the
surface of the earth.
In some embodiments, for example, the temperature of the collected reservoir
fluid is between:
(i) a temperature that is 10 degrees Celsius above the steam saturation
temperature at the
pressure within the hydrocarbon reservoir, and (ii) 350 degrees Celsius. In
some embodiments,
for example, the collected reservoir fluid 110 is free, or substantially free,
of the heating fluid. In
some embodiments, for example, the collected reservoir fluid 110 consists of,
or substantially
consists of, mobilized hydrocarbon material. Once disposed above the surface
of the earth
(such as, for example, within the surface facilities), the produced reservoir
fluid becomes
disposed in indirect heat exchange communication with a heat transfer fluid
such that heat is
indirectly transferred to the heat transfer fluid. The transferring of heat to
the heat transfer fluid
is such that the heat transfer fluid is evaporated. The evaporated heat
transfer fluid is
19
CA 2929924 2017-08-24

communicated to a turbine such that rotation of the turbine is effected, such
that electricity is
generated.
[0062] In some embodiments, for example, the laterally, or substantially
laterally, extending
section 102a of the production well 102 is co-operatively configured with the
electric heater 104
such that while the reservoir fluid is being conducted towards the well 102,
the laterally, or
substantially laterally, extending section 102a of the production well 102 is
disposed to receive
and collect the reservoir fluid across (but not necessarily continuously
across) a reservoir fluid-
receiving portion of the laterally, or substantially laterally, extending
section of the production
well 102, and the length of the reservoir fluid-receiving portion, measured
along the axis of the
operative portion, is at least 1000 metres. Because the heating fluid is not
supplied from the
surface, heat losses, associated with longer wells, is not concerning, as it
is for SAGD
operations. Also, because the volumetric flow of produced fluid is relatively
less than for SAGD
production, hydraulic pressure losses are also not a material factor for well
design. In
combination, this enables the use of longer wells in in-situ reflux operations
to effect production
of hydrocarbon material, although shorter wells (i.e. those less than 1000
metres) could also be
used.
[0063] In some embodiments, for example, the vertically, or
substantially vertically,
extending section 102b of the production well 102 has a length, measured along
the axis of the
vertically, or substantially vertically, extending section, of at least 1000
metres, so as to allow for
production from deeper resources. Again, heat losses and hydraulic pressure
losses, with in-
situ reflux are not concerning, as it is for SAGD operations, and it is,
possible to, therefore, use
longer wells, although shorter wells (i.e. those less than 1000 metres in
depth) could also be
used.
[0064] Liquid heating fluid may be supplied from a source disposed above
the surface 1002.
In some embodiments, for example, the supplying of liquid heating fluid is
effected via an
injector string 114 disposed within the production well 102. In some
embodiments, for example,
the injector string includes a "spaghetti string".
[0065] Supplying of liquid heating fluid may be suspended, when
sufficient refluxing of the
condensed heating fluid is being effected such that the desirable production
of reservoir fluid is
effected (for example, the produced reservoir fluid is free, or substantially
free, of heating fluid,
and/or, for example, the produced reservoir fluid consists of, or
substantially consists of,
hydrocarbon material). In some cases, after the supplying has been suspended,
periodic make-
up of heating fluid may be required. For example, liquid heating fluid may be
lost to the
CA 2929924 2017-08-24

reservoir 1000, and make-up heating fluid may be required. In this respect,
while the heating of
a liquid heating fluid is being effected, supplemental liquid heating fluid
116 may be supplied
from a source disposed above the surface 1002. In this respect, the liquid
heating fluid includes
the supplemental liquid heating fluid 116. In some embodiments, for example,
the supplying of
supplemental liquid heating fluid 116 is effected via an injector string 114
disposed within the
production well 102. In some embodiments, for example, the injector string
includes a
"spaghetti string". In some embodiments, for example, the supplying of the
supplemental liquid
heating fluid is effected in response to sensing of a pressure, within the
hydrocarbon reservoir
portion from which the mobilized hydrocarbon material is being produced, that
is less than a
predetermined pressure. The predetermined pressure is based on, amongst other
things, the
desirability of operating at higher pressures in order to provide a greater
driving force for
production, balanced versus the recognition that heat transfer efficiency is
greater at lower
pressures and that cap rock integrity may limit the maximum possible operating
pressure.
[0066] In operation, during start-up, the hydrocarbon reservoir is
heated by heat generated
by the electric heater, such that hydrocarbon material is mobilized by the
heating of the
hydrocarbon reservoir. The mobilized hydrocarbon material drains into the well
102. The
heating is effected by conduction, convection, or a combination of conduction
and convection.
In some embodiments, for example, the convective heating is effected by
evaporated formation
water, such that the heating fluid includes evaporated formation water.
Subsequently, or, in
parallel, heating fluid is supplied from the surface facilities and is
injected into the reservoir.
Evaporation of the injected heating fluid is effected by the heat generated by
the electric heater
104. The evaporated heating fluid is conducted to the hydrocarbon reservoir
and transfers heat
energy to the hydrocarbon material such that the hydrocarbon material is
mobilized and the
heating fluid is condensed. Reservoir fluid 110 enters the well 102 via ports
106, collects within
the collection reservoir 108 and is electrically heated by the electric heater
104 (either directly or
via the heater assembly 106). Heating is controlled such that the reservoir
fluid is, primarily,
collected mobilized hydrocarbon material. The heated reservoir fluid transfers
heat to
condensed heating fluid that is disposed in heat transfer communication with
the reservoir fluid,
thereby effecting re-evaporation of the condensed heating fluid, and thereby
effecting the reflux
112. Eventually, after sufficient hydrocarbon material has been mobilized and
drained into the
well 102 (such as, for example, as described above), an evaporated fluid
chamber develops
(where the heating fluid, in the liquid state, is water, then a steam chamber
would be
developed). In parallel, reservoir fluid collected within the production well
104 is continuously
produced, such as by a downhole pump and/or artificial lift, or by reservoir
pressure.
21
CA 2929924 2017-08-24

[0067]
Referring to Figure 2, in some embodiments, for example, the process is
effected by
a system 200 including a non-production well 202 and a production well 204. A
first electric
heater 206 is disposed within the non-production well 202. At least a fraction
of the reflux is
effected by a first electric heater 206. The producing of the produced fluid
224 is effected via
the production well 204. The production well 204 is disposed below the non-
production well
202. The non-production well 202 does not produce produced fluid 224. The non-
production
well is provided for, amongst other things, to effect reflux of the condensed
heating fluid. In
comparison to the embodiment illustrated in Figure 1, this configuration may
enable recovery
and production of hydrocarbon material that is disposed closer to the bottom
of the hydrocarbon
reservoir, with less energy losses to the formation below the hydrocarbon
reservoir without any
hydrocarbon reserves.
[0068]
The non-production well 202 extends into the hydrocarbon reservoir 2000 from
the
surface. In some embodiments, for example, the first electric heater 206 is
disposed within a
laterally extending section 202a of the non-production well 202, that extends
from a vertically
extending section 202b, at the heel 202c of the non-production well 202. In
some
embodiments, for example, the laterally extending section 202a is disposed
along a horizontal,
or substantially horizontal, axis.
[0069]
In some embodiments, for example, the first electric heater 206 is disposed
within
the collection reservoir 210 of the non-production well 202. The collection
reservoir 210
includes reservoir fluid 212 that has collected therein. In some embodiments,
for example, the
collected reservoir fluids 212 is free, or substantially free, of the heating
fluid. In some
embodiments, for example, the collected reservoir fluids 212 consists of, or
substantially
consists of, the mobilized hydrocarbon material. The collected mobilized
hydrocarbon material
is disposed in heat transfer communication with at least a fraction of the
condensed heating
fluid, such as condensed heating fluid that is disposed externally of the non-
production well 202.
In some embodiments, for example, the collected reservoir fluid may also
include the
condensed heating fluid.
[0070]
The first electric heater 206 is configured for effecting heating of the
collected
reservoir fluid 212. In some embodiments, for example, the first electric
heater is disposed in
direct heat transfer communication with the collected reservoir fluid. Heating
of any condensed
heating fluid, whether disposed as part of the collected reservoir fluid, or
disposed in heat
transfer communication with the collected reservoir fluid, externally of the
production well, is,
therefore, effected by the first electric heater, when the first electric
heater is heating the
22
CA 2929924 2017-08-24

collected reservoir fluid. In some embodiments, for example, the electrical
heating by the first
electric heater 206 is such that the collected reservoir fluid is free, or
substantially free, of
heating fluid. In some embodiments, for example, the electrical heating by the
first electric
heater 206 is such that the collected reservoir fluid consists of, or
substantially consists of, the
mobilized hydrocarbon material.
[0071]
Referring to Figure 3, in some embodiments, for example, the first electric
heater 206
is part of a heating assembly 700, such that the electric heater is in
indirect heat transfer
communication with the collected reservoir fluid via a liquid heat transfer
medium 704. An
example of a suitable liquid heat transfer medium 704 is glycerin. In this
respect, a heating
assembly 700 is provided, and includes a housing 702, the electric heater, and
the liquid heat
transfer medium 704. The electric heater is disposed within a housing 702,
with the space
between the electric heater and the housing 702 being occupied with the liquid
heat transfer
medium 704. The liquid heat transfer medium 704 has a higher boiling point
than that of the
heating fluid at the pressure of the hydrocarbon reservoir portion from which
the mobilized
hydrocarbon material is being produced, such as by at least 10 degrees
Celsius, such as, for
example, by at least 20 degrees Celsius, such as, for example, by at least 50
degrees Celsius,
such as, for example, by at least 100 degrees Celsius. The collection
reservoir 210 is defined
by a space within the non-production well 202, between the housing 702 and the
wellbore string
(such as, for example, casing) of the non-production well 202. Because the
heater assembly is
disposed within the collection reservoir, the liquid heat transfer medium 704
is disposed in heat
transfer communication with the collected reservoir fluid 212, through the
wall of the housing
702. In this respect, heat is transferred from the first electric heater to
the collected reservoir
fluid via the liquid heat transfer medium 704 and through the wall of the
housing 702. By virtue
of this configuration, any evaporated heating fluid may become disposed at a
relatively higher
temperature, owing to the fact that the liquid heat transfer medium 704 can be
heated to higher
temperatures by the first electric heater, and transfer this higher quality
heat to the reservoir
fluids (and, therefore, to the condensed heating fluid), versus direct heating
of the reservoir
fluids by the first electric heater (without any intervening liquid heat
transfer medium 704).
[0072]
In some embodiments, for example, the first electric heater 206 is disposed
within a
laterally extending section 202a of the non-production well 202, that extends
from a vertically
extending section 202b, at the heel 202c of the non-production well 202.
In some
embodiments, for example, the laterally extending section 202a is disposed
along a horizontal,
or substantially horizontal, axis.
23
CA 2929924 2017-08-24

[0073] In some embodiments, for example, the first electric heater 206
includes a plurality of
heater segments, and each one of the heater segments may be controllable
independently from
the other heater segments in terms of the rate of energy being produced. By
providing a
plurality of heater segments that are independently controllable, improved
control of heating
fluid conformance is made possible.
[0074] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 212 is such that the temperature of the collected reservoir fluid is
greater than or equal to at
least the boiling point of the liquid heating fluid at the pressure of the
hydrocarbon reservoir
portion from which the mobilized hydrocarbon material is being produced. In
this respect, both
of (i) evaporation of the heating fluid that is disposed in heat transfer
communication with the
collected reservoir fluid, but externally of the collection reservoir 210, and
(ii) evaporation of any
heating fluid that is present within the collected reservoir fluid, is
promoted, so as to return the
heating fluid to the reservoir for effecting mobilization of the hydrocarbon
material within the
reservoir 2000, and thereby contribute to the refluxing.
[0075] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 212 is effected in response to sensing of a temperature, of the
collected reservoir fluid,
that is at or below a predetermined temperature that is based upon the boiling
point of the liquid
heating fluid at the pressure of the hydrocarbon reservoir portion from which
the mobilized
hydrocarbon material is being produced. In some embodiments, prior to the
electrical heating of
the collected reservoir fluid, a temperature of the collected reservoir fluid
is sensed that is at or
below a predetermined temperature that is based upon the boiling point of the
liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. In some embodiments, for example, the
predetermined temperature
is at or above the boiling point of the liquid heating fluid at the pressure
of the hydrocarbon
reservoir portion from which the mobilized hydrocarbon material is being
produced. The
purpose of having the predetermined temperature being at the boiling point of
the liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced, is for evaporating liquid heating fluid that has
collected within the
well or is in close proximity to the well. Liquid heating fluid that has
collected within the well
would be disposed at or below the boiling point of the liquid heating fluid at
the pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced
(where the heating fluid, in the liquid state, is water, this would be the
saturated steam
temperature within the reservoir). By effecting electrical heating while the
collected reservoir
24
CA 2929924 2017-08-24

, fluid is disposed at or below the boiling point of the liquid heating fluid
at the pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced,
the intention is to vaporize the liquid heating fluid that has collected
within the well as part of the
collected reservoir fluid. In some embodiments, for example, it may be
intended to vaporize the
heating fluid that is disposed externally of the well, in which case the
predetermined
temperature may be above the boiling point of the liquid heating fluid at the
pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced,
for purposes of precluding collection of the heating fluid within the well.
[0076]
In some embodiments, for example, the non-production well 202 includes the
heel
202c. In this respect, the electrical heating of the collected reservoir fluid
by the electric heater
206 is such that the temperature of the collected reservoir fluid, disposed at
the heel 202c of the
non-production well 202, is greater than or equal to the boiling point of the
liquid heating fluid at
the pressure of the hydrocarbon reservoir portion from which the mobilized
hydrocarbon
material is being produced. Similar to the above, both of (i) evaporation of
the heating fluid that
is disposed in heat transfer communication with the collected reservoir fluid,
but externally of the
collection reservoir, and (ii) evaporation of any heating fluid that is
present within the collected
reservoir fluid, is promoted, so as to return the heating fluid to the
reservoir for effecting
mobilization of the hydrocarbon material within the reservoir, and thereby
contribute to the
refluxing.
[0077] In
some embodiments, for example, the electrical heating of the collected
reservoir
fluid by the first electric heater 206 is effected in response to sensing of a
temperature, of the
collected reservoir fluid disposed at the heel 202c of the non-production well
202, that is at or
below a predetermined temperature that is based upon the boiling point of the
liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. In some embodiments, for example, prior to the
electrical heating of
the collected reservoir fluid by the first electric heater 206, a temperature,
of the collected
reservoir fluid that is disposed at the heel 202c of the non-production well
202, is sensed that is
at or below a predetermined temperature that is based upon the boiling point
of the liquid
heating fluid at the pressure of the hydrocarbon reservoir portion from which
the mobilized
hydrocarbon material is being produced.
In some embodiments, for example, the
predetermined temperature is at or above the boiling point of the liquid
heating fluid at the
pressure of the hydrocarbon reservoir portion from which the mobilized
hydrocarbon material is
being produced. The purpose of having the predetermined temperature being at
the boiling
CA 2929924 2017-08-24

, ,
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, is for evaporating
liquid heating fluid that
has collected within the well. Liquid heating fluid that has collected within
the well would be
disposed at or below the boiling point of the liquid heating fluid at the
pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced
(where the heating fluid, in the liquid state, is water, this would be the
saturated steam
temperature within the reservoir). By effecting electrical heating while the
collected reservoir
fluid is disposed at or below the boiling point of the liquid heating fluid at
the pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced,
the intention is to vaporize the liquid heating fluid that has collected
within the well as part of the
collected reservoir fluid. In some embodiments, for example, it may be
intended to vaporize the
heating fluid that is disposed externally of the well, in which case the
predetermined
temperature may be above the boiling point of the liquid heating fluid at the
pressure of the
hydrocarbon reservoir portion from which the mobilized hydrocarbon material is
being produced,
for purposes of precluding collection of the heating fluid within the well.
[0078] As discussed above, in some embodiments, for example, the
collected reservoir fluid
212 consists of, or substantially consists of, the mobilized hydrocarbon
material, and, in this
respect, is free, or substantially free, of the heating fluid. In those
embodiments where the first
electric heater is disposed in direct heat transfer communication with the
collected reservoir
fluid, by having the collected reservoir fluid consisting of, or substantially
consisting of, the
mobilized hydrocarbon material (and, in this respect, free, or substantially
free, of the heating
fluid) evaporation of condensed heating fluid disposed in heat transfer
communication with the
collected reservoir fluid, may produce evaporated heating fluid having a
relatively higher
temperature, owing to the fact that the mobilized hydrocarbon material can be
heated to higher
temperatures by the first electric heater 206, and transfer this higher
quality heat to any
condensed heating fluid disposed in heat transfer communication with the
collected reservoir
fluid, versus direct heating of the condensed heating fluid by the first
electric heater (without any
intervening liquid heat transfer medium 704).
[0079] Also, by having the collected reservoir fluid 212 be free, or
substantially free, of the
heating fluid, scale formation within the non-production well 202 may be
mitigated. Where the
heating fluid, in its liquid state, includes water, it is preferable that
water does not become
disposed in contact structures within the non-production well 202, including
the first electric
heater 206, as evaporation of water in this context may result in
precipitation of dissolved scale-
26
CA 2929924 2017-08-24

forming solids within the non-production well, including onto the first
electric heater or other
structures, resulting in scale formation. Accordingly, in such embodiments, by
ensuring that the
collected reservoir fluid be free, or substantially free, of the heating
fluid, the collected heating
fluid is fluidically isolated, or substantially fluidically isolated, from the
non-production well,
.. thereby mitigating potential scale formation within the non-production well
(including scale
formation on the second electric heater 220).
[0080] In this respect, in some embodiments, for example, the rate of
heating of the
collected reservoir fluid 212 by the first electric heater 206 is modulated
such that the collected
reservoir fluid is free, or substantially free, of the heating fluid. In some
embodiments, for
example, the rate of heating of the collected reservoir fluid 212 by the first
electric heater 206 is
modulated such that the collected reservoir fluid consists of, or
substantially consists of, the
mobilized hydrocarbon material.
[0081] In some embodiments, for example, the composition of the
collected reservoir fluid
212 may be sensed by a densitometer. In this respect, the rate of heating
effected by the first
electric heater 206 may be modulated based on sensing of the density of the
collected reservoir
fluid by the densitometer. In response to sensing of a density of the
collected reservoir fluid that
is characteristic of a collected reservoir fluid having excessive non-
hydrocarbon fluid (such as
the heating fluid), the rate of heating by the second electric heater 220 may
be increased to
effect evaporation of the fluid. This will promote the maintenance of a
collected reservoir fluid
that consists of hydrocarbon material, or substantially hydrocarbon material,
and, in this respect,
is free, or substantially free, of the heating fluid. Amongst other things,
this promotes reflux of
the condensed heating fluid (as above-described), higher quality heat transfer
to effect the
evaporation of the condensed heating fluid, and mitigates scale formation.
[0082] Alternatively, the amount of water within the produced reservoir
fluid can be detected
by measuring electrical resistance of the produced reservoir fluid,
capacitance of the produced
reservoir fluid, or both of electrical resistance and capacitance of the
produced reservoir fluid,
and the rate of heating by the electric heater may be modulated in response to
this
measurement.
[0083] The produced fluid 224 is produced through the production well
204. In some
embodiments, for example, production is effected by artificial lift, such as
by a downhole pump
and/or by gas lift.
27
CA 2929924 2017-08-24

[0084] The production well 204 extends into the hydrocarbon reservoir
from the surface.
The production well 204 includes a collection reservoir 224 for collecting
reservoir fluids 226.
The reservoir fluids include mobilized hydrocarbon material and condensed
heating fluid. In
some embodiments, for example, the reservoir fluid being collected within the
production well is
free, or substantially free, of the heating fluid. In some embodiments, for
example, the reservoir
fluid being collected within the production well consists of, or substantially
consists of, mobilized
hydrocarbon material. Such collected reservoir fluid may be in heat transfer
communication
with condensed heating fluid that has bypassed the non-production well 202. In
some
embodiments, for example, the collected reservoir fluid may include the
mobilized hydrocarbon
material and condensed heating fluid that has bypassed the non-production well
202. The
condensed heating fluids are more likely to be disposed in such relationships
with the collected
reservoir fluid in later-stage in-situ reflux processes being practised within
oil sands. In more
mature operations, the steam chamber tends to laterally grow, resulting in
condensed heating
fluid bypassing the non-production well 202 while draining within the
reservoir.
[0085] In some embodiments, for example, it may be desirable to remove
condensed
heating fluid from the reservoir fluid 224 being collected within the
production well 204, prior to
production of the reservoir fluid, as well as to reflux such condensed heating
fluid that has
bypassed the non-production well 202.
[0086] In this respect, a second electric heater 220 is disposed within
the production well
and, more specifically, within the collection reservoir 224 of the production
well 204. The
collection reservoir includes reservoir fluid that has collected therein.
[0087] The second electric heater 220 is configured for effecting
heating of the collected
reservoir fluid 226. In some embodiments, for example, the second electric
heater is disposed
in direct heat transfer communication with the collected reservoir fluid.
Heating of any
condensed heating fluid, whether disposed as part of the collected reservoir
fluid, or disposed in
heat transfer communication with the collected reservoir fluid, externally of
the production well
204, is, therefore, effected by the second electric heater, when the second
electric heater is
heating the collected reservoir fluid. In some embodiments, for example, the
electrical heating
by the second electric heater 220 is such that the collected reservoir fluid
is free, or substantially
free, of heating fluid. In some embodiments, for example, the electrical
heating by the second
electric heater 220 is such that the collected reservoir fluid consists of, or
substantially consists
of, the mobilized hydrocarbon material.
28
CA 2929924 2017-08-24

,
,
[0088] Referring to Figure 3, in some embodiments, for example, the
second electric heater
220 is part of a heating assembly 700, such that the second electric heater is
in indirect heat
transfer communication with the collected reservoir fluid 226 via a liquid
heat transfer medium
704. An example of a suitable liquid heat transfer medium 704 is glycerin. In
this respect, a
heating assembly 700 is provided, and includes a housing 702, second the
electric heater, and
the liquid heat transfer medium 704. The second electric heater is disposed
within a housing
702, with the space between the second electric heater and the housing 702
being occupied
with the liquid heat transfer medium 704. The liquid heat transfer medium 704
has a higher
boiling point than that of the heating fluid at the pressure of the
hydrocarbon reservoir portion
from which the mobilized hydrocarbon material is being produced, such as by at
least 10
degrees Celsius, such as, for example, by at least 20 degrees Celsius, such
as, for example, by
at least 50 degrees Celsius, such as, for example, by at least 100 degrees
Celsius. The
collection reservoir 224 is defined by a space within the production well,
between the housing
702 and the casing of the production well 204. Because the heater assembly is
disposed within
the collection reservoir, the liquid heat transfer medium 704 is disposed in
heat transfer
communication with the collected reservoir fluid, through the wall of the
housing 702. In this
respect, heat is transferred from the second electric heater to the collected
reservoir fluid via the
liquid heat transfer medium 704 and through the wall of the housing 702. By
virtue of this
configuration, any evaporated heating fluid may become disposed at a
relatively higher
temperature, owing to the fact that the liquid heat transfer medium 704 can be
heated to higher
temperatures by the second electric heater, and transfer this higher quality
heat to the reservoir
fluids (and, therefore, to the condensed heating fluid), versus direct heating
of the reservoir
fluids by the second electric heater (without any intervening liquid heat
transfer medium 704).
This also facilitates production of a "drier" hydrocarbon material.
[0089] In some embodiments, for example, the second electric heater 220 is
disposed
within a laterally extending section 204a of the production well 204, that
extends from a
vertically extending section 204b, at the heel 204c of the production well
204. In some
embodiments, for example, the laterally extending section 204a is disposed
along a horizontal,
or substantially horizontal, axis.
[0090] In some embodiments, for example, the second electric heater 220
includes a
plurality of heater segments, and each one of the heater segments may be
controllable
independently from the other heater segments in terms of the rate of energy
being produced.
29
CA 2929924 2017-08-24

By providing a plurality of heater segments that are independently
controllable, improved control
of heating fluid conformance is made possible.
[0091] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 226 is such that the temperature of the collected reservoir fluid is
greater than or equal to at
least the boiling point of the liquid heating fluid at the pressure of the
hydrocarbon reservoir
portion from which the mobilized hydrocarbon material is being produced. In
this respect, both
of (i) evaporation of the heating fluid that is disposed in heat transfer
communication with the
collected reservoir fluid, but externally of the collection reservoir, and
(ii) evaporation of any
heating fluid that is present within the collected reservoir fluid, is
promoted, so as to return the
.. heating fluid to the reservoir for effecting mobilization of the
hydrocarbon material within the
reservoir, and thereby contribute to the refluxing. As well, by promoting the
evaporation, the
produced fluid 224 that is being produced contains less heating fluid, thereby
reducing energy
requirements to transport the produced fluid to the surface (as there is less
fluid volume to
produce), and also reducing demands on separation processes for removal of
heating fluid from
the produced fluids.
[0092] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 226 is effected in response to sensing of a temperature, of the
collected reservoir fluid,
that is at or below a predetermined temperature that is based upon the boiling
point of the liquid
heating fluid at the pressure of the hydrocarbon reservoir portion from which
the mobilized
hydrocarbon material is being produced. In some embodiments, prior to the
electrical heating of
the collected reservoir fluid, a temperature of the collected reservoir fluid
is sensed that is at or
below a predetermined temperature that is based upon the boiling point of the
liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. In some embodiments, for example, the
predetermined temperature
is at or above the boiling point of the liquid heating fluid at the pressure
of the hydrocarbon
reservoir portion from which the mobilized hydrocarbon material is being
produced. The
purpose of having the predetermined temperature being at the boiling point of
the liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced, is for evaporating liquid heating fluid that has
collected within the
.. well. Liquid heating fluid that has collected within the well would be
disposed at or below the
boiling point of the liquid heating fluid at the pressure of the hydrocarbon
reservoir portion from
which the mobilized hydrocarbon material is being produced (where the heating
fluid, in the
liquid state, is water, this would be the saturated steam temperature within
the reservoir). By
CA 2929924 2017-08-24

effecting electrical heating while the collected reservoir fluid is disposed
at or below the boiling
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, the intention is to
vaporize the liquid
heating fluid that has collected within the well as part of the collected
reservoir fluid. In some
embodiments, for example, it may be intended to vaporize the heating fluid
that is disposed
externally of the well, in which case the predetermined temperature may be
above the boiling
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, for purposes of
precluding collection of
the heating fluid within the well.
[0093] In some embodiments, for example, the production well 204 includes
the heel 204c.
In this respect, the electrical heating of the collected reservoir fluid 226
by the second electric
heater 220 is such that the temperature of the collected reservoir fluid,
disposed at the heel
204c of the production well 204, is greater than or equal to the boiling point
of the liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. Similar to the above, both of (i) evaporation of
the heating fluid that
is disposed in heat transfer communication with the collected reservoir fluid,
but externally of the
collection reservoir, and (ii) evaporation of any heating fluid that is
present within the collected
reservoir fluid, is promoted, so as to return the heating fluid to the
reservoir for effecting
mobilization of the hydrocarbon material within the reservoir, and thereby
contribute to the
refluxing. As well, by promoting the evaporation, the produced fluid 224 that
is being produced
contains less heating fluid, thereby reducing energy requirements to transport
the produced fluid
to the surface (as there is less fluid volume to produce), and also reducing
demands on
separation processes for removal of heating fluid from the produced fluids.
[0094] In some embodiments, for example, the electrical heating of the
collected reservoir
fluid 226 by the second electric heater 220 is effected in response to sensing
of a temperature,
of the collected reservoir fluid disposed at the heel 204c of the production
well 204, that is at or
below a predetermined temperature that is based upon the boiling point of the
liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced. In some embodiments, for example, prior to the
electrical heating of
the collected reservoir fluid by the second electric heater, a temperature, of
the collected
reservoir fluid that is disposed at the heel 204c of the production well 204,
is sensed that is at or
below a predetermined temperature that is based upon the boiling point of the
liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
31
CA 2929924 2017-08-24

material is being produced. In some embodiments, for example, the
predetermined temperature
is at or above the boiling point of the liquid heating fluid at the pressure
of the hydrocarbon
reservoir portion from which the mobilized hydrocarbon material is being
produced. The
purpose of having the predetermined temperature being at the boiling point of
the liquid heating
fluid at the pressure of the hydrocarbon reservoir portion from which the
mobilized hydrocarbon
material is being produced, is for evaporating liquid heating fluid that has
collected within the
well. Liquid heating fluid that has collected within the well would be
disposed at or below the
boiling point of the liquid heating fluid at the pressure of the hydrocarbon
reservoir portion from
which the mobilized hydrocarbon material is being produced (where the heating
fluid, in the
liquid state, is water, this would be the saturated steam temperature within
the reservoir). By
effecting electrical heating while the collected reservoir fluid is disposed
at or below the boiling
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, the intention is to
vaporize the liquid
heating fluid that has collected within the well as part of the collected
reservoir fluid. In some
embodiments, for example, it may be intended to vaporize the heating fluid
that is disposed
externally of the well, in which case the predetermined temperature may be
above the boiling
point of the liquid heating fluid at the pressure of the hydrocarbon reservoir
portion from which
the mobilized hydrocarbon material is being produced, for purposes of
precluding collection of
the heating fluid within the well.
[0095] As discussed above, in some embodiments, for example, the collected
reservoir fluid
226 consists of, or substantially consists of, the mobilized hydrocarbon
material. In those
embodiments where the second electric heater 206 is disposed in direct heat
transfer
communication with the collected reservoir fluid, by having the collected
reservoir fluid
consisting of, or substantially consisting of, the mobilized hydrocarbon
material, evaporation of
condensed heating fluid, disposed in heat transfer communication with the
collected reservoir
fluid, may produce evaporated heating fluid having a relatively higher
temperature, owing to the
fact that the mobilized hydrocarbon material can be heated to higher
temperatures by the
second electric heater, and transfer this higher quality heat to any condensed
heating fluid
disposed in heat transfer communication with the collected reservoir fluid,
versus direct heating
of the condensed heating fluid by the second electric heater (without any
intervening liquid heat
transfer medium 704).
[0096] Also, by having the collected reservoir fluid 226 be free, or
substantially free, of the
heating fluid, scale formation within the production well 204 may be
mitigated. Where the
32
CA 2929924 2017-08-24

heating fluid, in its liquid state, includes water, it is preferable that
water does not become
disposed with structures within the production well, including the second
electric heater 206, as
evaporation of water in this context may result in precipitation of dissolved
scale-forming solids
within the production well, including onto the second electric heater or other
structures, resulting
in scale formation. Accordingly, in such embodiments, by ensuring that the
collected reservoir
fluid is free, or substantially free, of the heating fluid, the collected
heating fluid is fluidically
isolated, or substantially fluidically isolated, from the production well,
thereby mitigating potential
scale formation within the production well (including scale formation on the
second electric
heater).
[0097] Further, as a necessary incident, by having the collected reservoir
fluid 226 be free,
or substantially free, of the heating fluid, production of a "drier"
hydrocarbon material is
facilitated. This reduces energy requirements to transport the produced fluid
224 to the surface
2006 (as there is less fluid volume to produce) and also reduces demands on
separation
processes for removal of heating fluid from the produced fluids.
[0098] In this respect, in some embodiments, for example, the rate of
heating of the
collected reservoir fluid by the second electric heater 220 is modulated such
that the collected
reservoir fluid 226 consists of, or substantially consists of, the mobilized
hydrocarbon material,
and, in this respect, is free, or substantially free, of the heating fluid.
[0099] In some embodiments, for example, the composition of the
collected reservoir fluid
__ 226 may be sensed by a densitometer. In this respect, the rate of heating
effected by the
electric heater 220 may be modulated based on sensing of the density of the
collected reservoir
fluid by the densitometer. In response to sensing of a density of the
collected reservoir fluid that
is characteristic of a collected reservoir fluid having excessive non-
hydrocarbon fluid (such as
the heating fluid), the rate of heating by the electric heater 220 may be
increased to effect
evaporation of the fluid. This will promote the maintenance of a collected
reservoir fluid that
consists of hydrocarbon material, or substantially hydrocarbon material, and,
in this respect, is
free, or substantially free, of the heating fluid. This promotes reflux of the
condensed heating
fluid (as above-described), higher quality heat transfer to effect the
evaporation of the
condensed heating fluid, mitigates scale formation, and production of "drier"
hydrocarbon
material.
[00100] In some embodiments, for example, the electric heater 220 is
submerged within the
collected reservoir fluid 226 (consisting of hydrocarbon material, or
substantially hydrocarbon
material, and, in this respect, being free, or substantially free, of the
heating fluid), and the
33
CA 2929924 2017-08-24

producing is modulated such that sufficient collected reservoir fluid is
maintained within the
production well 204 such that the electric heater is submerged within
collected reservoir fluid.
[00101] In those embodiments where the temperature of the collected
reservoir fluid 226,
within the production well 204, is above the boiling point of the liquid
heating fluid at the
pressure of the hydrocarbon reservoir portion from which the mobilized
hydrocarbon material is
being produced, the collected reservoir fluid is produced, such that the
produced collected
reservoir fluid 224 is conducted to above the surface of the earth. In some
embodiments, for
example, the temperature of the collected reservoir fluid is between: (i) a
temperature that is 10
degrees Celsius above the steam saturation temperature at the pressure within
the hydrocarbon
reservoir, and (ii) 350 degrees Celsius. In some embodiments, for example, the
collected
reservoir fluid 226 consists of, or substantially consists of, mobilized
hydrocarbon material, and,
in some embodiments, for example, is free, or substantially free, of the
heating fluid. Once
disposed above the surface of the earth (such as, for example, within the
surface facilities), the
collected reservoir fluid becomes disposed in indirect heat exchange
communication with a heat
transfer fluid such that heat is indirectly transferred to the heat transfer
fluid. The transferring of
heat to the heat transfer fluid is such that the heat transfer fluid is
evaporated. The evaporated
heat transfer fluid is communicated to a turbine such that rotation of the
turbine is effected, such
that electricity is generated.
[00102] In some embodiments, for example, the laterally extending section
204a of the
production well 204 is disposed below that of the laterally extending section
of the non-
production well 202. In some of these embodiments, for example, the laterally
extending
section of the production well 204 is disposed in alignment, or substantially
alignment, with the
laterally extending section of the non-production well 202.
[00103] In some embodiments, for example, the laterally, or substantially
laterally, extending
section 204a of the production well 204 is co-operatively configured with the
electric heater 220
such that while the reservoir fluid is being conducted towards the well 204,
the laterally, or
substantially laterally, extending section of the production well is disposed
to receive and collect
the reservoir fluid across (but not necessarily continuously across) a
reservoir fluid-receiving of
the laterally, or substantially laterally, extending section of the production
well, and the length of
the operative portion, measured along the axis of the reservoir fluid-
receiving portion, is at least
1000 metres. Because significant heating fluid is not supplied from the
surface, heat losses,
associated with longer wells, is not concerning, as it is for SAGD operations.
Also, because the
volumetric flow of produced fluid is relatively less than for SAGD production,
hydraulic pressure
34
CA 2929924 2017-08-24

losses are also not a material factor for well design. In combination, this
enables the use of
longer wells in in-situ reflux operations to effect production of hydrocarbon
material, although
shorter wells (i.e. those less than 1000 metres) could also be used.
[00104]
In some embodiments, for example, the vertically, or substantially
vertically,
extending section 204b of the production well 204 has a length, measured along
the axis of the
vertically, or substantially vertically, extending section, of at least 1000
metres, so as to allow
production from deeper resources. Again, heat losses and hydraulic pressure
losses, with in-
situ reflux are not concerning, as it is for SAGD operations, and it is,
possible to, therefore, use
longer wells, although shorter wells (i.e. those less than 1000 metres in
depth) could also be
used.
[00105] In some embodiments, for example, where the hydrocarbon reservoir
contains
relatively less viscous hydrocarbon material that is targeted for production,
the non-production
and production wells 202, 204 may be spaced apart a relatively greater
distance than SAGD
well pairs, such as by a spacing distance that is greater than five (5)
metres, such as ten (10)
metres.
[00106]
In some embodiments, for example, the heating fluid being electrically
heated within
the non-production well 202, in its liquid state, may include formation water
that is resident
within the hydrocarbon reservoir, or may include heating fluid (for example,
water) that is
injected into the hydrocarbon reservoir and supplied from above the surface,
or may include
both of the formation water and the injected heating fluid. In some
embodiments, for example,
the supplying of supplied liquid heating fluid 118 is effected via an injector
string 216 disposed
within the non-production well 202.
In some embodiments, for example, the injector string
includes a "spaghetti string". In those embodiments where at least a fraction
of the liquid
heating fluid is being supplied from above the surface, in some of these
embodiments, for
.. example, the ratio of the volumetric rate at which the supplied liquid
heating fluid is being
supplied to the rate at which heat energy is being delivered by the electric
heater is less than 25
cubic metres per day per megawatt, such as, for example, less than 10 cubic
metres per day
per megawatt.
[00107]
In some embodiments, for example, heating fluid may be lost to the
reservoir, and
make-up heating fluid may be required. In this respect, while the heating of a
liquid heating fluid
is being effected, supplemental liquid heating fluid may be supplied from a
source disposed
above the surface 2002, such as via the injection string 216. In this respect,
the liquid heating
fluid includes the supplemental liquid heating fluid. In some embodiments, for
example, the
CA 2929924 2017-08-24

supplying of the supplemental liquid heating fluid is effected in response to
sensing of a
pressure, within the hydrocarbon reservoir portion from which the mobilized
hydrocarbon
material is being produced, that is less than a predetermined pressure. The
predetermined
pressure is based on, amongst other things, the desirability of operating at
higher pressures in
order to provide a greater driving force for production, balanced versus the
recognition that heat
transfer efficiency is more efficient at lower pressures and that cap rock
integrity may limit the
maximum possible operating pressure. The injector string 216 may be disposed
outside of the
well, and could also be used to inject heating fluid during start-up.
[00108] In operation, during start-up, the hydrocarbon reservoir is
heated by heat generated
by the first and second electric heaters 206, 220 (either directly or via the
heater assembly),
such that hydrocarbon material is mobilized by the heating of the hydrocarbon
reservoir. The
mobilized hydrocarbon material drains and enters the non-production well 202
via ports 208.
The heating is effected by conduction, convection, or a combination of
conduction and
convection. In some embodiments, for example, the convective heating is
effected by
evaporated formation water, such that the heating fluid includes evaporated
formation water.
Subsequently, or, in parallel, heating fluid is supplied from the surface
facilities and is injected
into the hydrocarbon reservoir. Evaporation of the injected heating fluid is
effected by the heat
generated by the electric heater 206. The evaporated heating fluid is
conducted to the
hydrocarbon reservoir and transfers heat energy to the hydrocarbon material
such that the
hydrocarbon material is mobilized and the heating fluid is condensed.
[00109] Reservoir fluid enters the non-production well 202 via ports 208,
collects within the
collection reservoir 210 and is heated by the first electric heater 206
(either directly or via the
heater assembly). The heating is controlled such that the collected reservoir
fluid is free, or
substantially free, of heating fluid, and, in some embodiments, for example,
consists of, or
.. substantially consists of, the mobilized hydrocarbon material. The heated
reservoir fluid
transfers heat to condensed heating fluid that is disposed in heat transfer
communication with
the reservoir fluid, thereby effect re-evaporation of the condensed heating
fluid, and thereby
effect the reflux 214.
[00110] Reservoir fluid 226 also drains, by gravity, and enters the
production well 204
through ports 222, and is collected within the collection reservoir defined
within the production
well 204, and is heated by the second electric heater. The heating is
controlled such that the
collected reservoir fluid is free, or substantially free, of heating fluid,
and, in some embodiments,
for example, consists of, or substantially consists of, the mobilized
hydrocarbon material. The
36
CA 2929924 2017-08-24

heated reservoir fluid transfers heat to any condensed heating fluid that is
disposed in heat
transfer communication with the reservoir fluid, thereby effect re-evaporation
of the condensed
heating fluid, and thereby effect the reflux 228, and also thereby providing a
drier hydrocarbon
material for production.
[00111] Eventually, after sufficient hydrocarbon material has been
mobilized and drained into
the non-production and production wells 202, 204 (such as, for example, as
described above),
an evaporated heating fluid chamber develops (where the heating fluid, in the
liquid state, is
water, then a steam chamber would be developed). The developed evaporated
heating fluid
chamber enables evaporated heating fluid to be conducted to hydrocarbon
material within the
hydrocarbon reservoir (and, more specifically, at the edge of the chamber) so
as to heat,
mobilize and then drive drainage of the hydrocarbon material towards the
production well 204.
In parallel, the drained hydrocarbon material may be produced from the
production well 204
using reservoir pressure or with assistance of artificial lift, such as with a
downhole pump or gas
lift.
[00112] In some embodiments, for example, it may be desirable, after the
hydrocarbon
reservoir has been sufficiently heated in the region surrounding the
production well 204, to
reduce the rate at which heat is generated by the second electric heater, or
suspend the
generation of heat by the second electric heater, thereby reducing operating
costs and also
mitigating coking. In this respect, the process includes:
during a first time interval, effecting electrical heating of the hydrocarbon
reservoir
with both of the first and second electric heaters (in some embodiments, for
example, liquid
heating fluid is supplied through the non-production well 202 and is heating
by the first electric
heater, and, in some embodiments, for example, liquid heating fluid may also
be supplied
through the production well 204 and be heated by the second electric heater);
and
after the first time interval, and during a second time interval, while either
one of:
(a) the second electrical heater is delivering heat energy at a rate that is
less than
50% of the rate at which heat energy is being delivered by the second
electrical heater during
the first time interval, or
(b) the electrical heating being effected by the second electrical heater has
become
suspended;
and while continuing to effect the electrical heating with the first electric
heater:
37
CA 2929924 2017-08-24

(a) supplying a liquid heating fluid to the hydrocarbon reservoir through
the
non-production well 202, such that a combined heating fluid, including the
supplied liquid
heating fluid and a condensed heating fluid, is evaporated to produce a
gaseous heating fluid
that is conducted into the reservoir and then condensed upon heating of
hydrocarbon material
to produce the condensed heating fluid; and
(b) producing, via the production well 204, reservoir fluid that has
collected
within the production well 204, wherein the collected reservoir fluid includes
hydrocarbon
material that has been mobilized by the electrical heating.
[00113] The electrical heating of the hydrocarbon reservoir during the
first time interval, in
combination with the electrical heating of the hydrocarbon reservoir during
the second time
interval by the first electric heater and any electrical heating of the
hydrocarbon reservoir during
the second time interval by the second electrical heater, is sufficient to,
during the second time
interval, effect evaporation of the condensed heating fluid, that has been
condensed after
having effected heating and mobilization of the hydrocarbon material, prior to
the condensed
heating fluid being received by the production well 204.
[00114] In some embodiments, for example, the electrical heating of the
hydrocarbon
reservoir during the first time interval, in combination with the electrical
heating of the
hydrocarbon reservoir during the second time interval by the first electric
heater and any
electrical heating of the hydrocarbon reservoir during the second time
interval by the second
electrical heater, is sufficient to, during the second time interval, effect
evaporation of the
condensed heating fluid, that has been condensed after having effected heating
and
mobilization of the hydrocarbon material, prior to the condensed heating fluid
being received by
the production well 204, such that the collected reservoir fluid consists of,
or substantially
consists of, the mobilized hydrocarbon material and, in this respect, is free,
or substantially free,
of heating fluid.
[00115] Reducing the rate at which heat energy is being delivered by the
electrical heater to
the reservoir fluid that has collected within the production well 204, after
sufficient electrical
heating of the hydrocarbon reservoir during the first time interval, mitigates
coking while also
enabling the production of reservoir fluid, collecting within the production
well, that is free, or
substantially free, of the heating fluid. In some embodiments, for example,
the collected
reservoir fluid consists of, or substantially consists of, hydrocarbon
material. It is believed that,
after sufficient time, continued heating, at the same rate, by the second
electric heater becomes
unnecessary to effect evaporation of the condensed heating fluid, that has
been condensed
38
CA 2929924 2017-08-24

after effecting heating and mobilization of the hydrocarbon material, prior to
the condensed
heating fluid being received by the production well 204, and that the rate at
which such heat
energy is being delivered can be reduced.
[00116] In some embodiments, for example, during the first time interval,
supplying of a liquid
heating fluid is also being effected via the non-production well 202, such
that a combined
heating fluid, including the supplied liquid heating fluid and a condensed
heating fluid, is
evaporated to produce a gaseous heating fluid that is conducted into the
reservoir and then
condensed upon heating of hydrocarbon material to produce the condensed
heating fluid.
[00117] In some embodiments, for example, during the first time interval,
the heat being
.. generated by the first electric heater effects heating of the reservoir
fluid that has collected
within the non-production well such that the collected reservoir fluid is
free, or substantially free,
of heating fluid. In some embodiments, for example, the collected reservoir
fluid consists of, or
substantially consists of, hydrocarbon material that has been heated and
mobilized by the
gaseous heating fluid and drained to the non-production well. In this respect,
the hydrocarbon
material, that has been collected within the non-production well function as a
heat transfer
medium, transferring heat generated by the first electric heater to the
condensed heating fluid
disposed externally of the non-production well. As well, during the first time
interval, reservoir
fluid, including hydrocarbon material that has been heated and mobilized by
the gaseous
heating fluid, that has been collected within the production well 204, is
produced via the
production well 204. In some of these embodiments, for example, during the
first time interval,
the electrical heating by the second electrical heater is such that the
temperature of the
collected reservoir fluid is less than 350 degrees Celsius (such as, for
example, less than 350
degrees Celsius, such as, for example, less than 250 degrees Celsius, such as,
for example,
less than 220 degrees Celsius), thereby mitigating coking within the
production well 204 during
the first time interval.
[00118] In one aspect, the hydrocarbon reservoir 1000 is spaced apart
from the earth's
surface 1002 by a minimum distance of less than 75 metres, such as, for
example, less than 50
metres. Because the subject process can be operated at relatively low
pressures (as compared
to, for example, SAGD), implementation of the process in relatively shallow
reservoirs is made
possible, as the risk of adversely affecting the environment at or near the
earth's surface,
including risk of contaminating ground water, is mitigated.
[00119] In another aspect, the process includes a lower pressure phase
and a higher
pressure phase.
39
CA 2929924 2017-08-24

[00120]
During the lower pressure phase, the pressure within the reservoir is
disposed below
a predetermined low pressure. In some embodiments, for example, the pressure
within the
reservoir 1000 is maintained below the predetermine low pressure by co-
operatively controlling
the rate at which supplemental liquid heating fluid is supply into the
reservoir 1000 (such as, for
example, from the surface) for heating by the electrical heater with the rate
at which the
produced fluid is being produced. In some embodiments, for example, the
predetermined low
pressure is less than 1500 kPa, such as, for example, less than 1000 kPa, such
as, for
example, 750 kPa. In some embodiments, for example, the predetermined low
pressure is 500
kPa.
[00121] After having operated the lower pressure phase, the low pressure phase
is
suspended and pressure within the reservoir 1000 is then increased to above
the predetermined
high pressure. In some embodiments, for example, the pressure increase is
effected at a rate
of increase in pressure within the reservoir 1000 of at least about 3 kPa per
day, such as, for
example, at least 5 kPa per day, such as, for example, at least 1 kPa per day.
[00122] In some embodiments, for example, at the time of suspension of the
low pressure
phase, supplemental liquid heating fluid is being supplied into the reservoir
100, for heating by
the electrical heater, while the produced fluid is being produced.
In some of these
embodiments, for example, the increase in pressure is effected by decreasing
the rate of
production of the produced fluid, while continuing supplying of the
supplemental liquid heating
fluid into the reservoir, for heating by the electrical heater, at the same or
substantially the same
rate. In other ones of these embodiments, for example, the increase in
pressure is effected by
continuing production of the produced fluid at the same or substantially the
same rate, while
increasing the rate at which supplemental liquid heating fluid is being
supplied into the reservoir
1000 for heating by the electrical heater. In this respect, in those
embodiments where
supplemental liquid heating fluid is being supplied into the reservoir 100,
for heating by the
electrical heater, while the produced fluid is being produced, the pressure
within the reservoir is
increased by co-operatively modulating the rate at which the supplemental
liquid heating fluid is
being supplied to the reservoir 1000 for heating by the electrical heater with
modulating of the
rate at which the produced fluid is produced from the reservoir 1000.
[00123] In some embodiments, for example, at the time of suspension of the low
pressure
phase, there is an absence of supplying of supplemental liquid heating fluid
into the reservoir
100, for heating by the electrical heater, while the produced fluid is being
produced. In some of
CA 2929924 2017-08-24

these embodiments, for example the increase in pressure is effected by
decreasing the rate of
production of the produced fluid.
[00124]
During the higher pressure phase, the pressure within the reservoir is
disposed
above a predetermined high pressure. In some embodiments, for example, the
pressure within
the reservoir 1000 is maintained above the predetermine high pressure by co-
operatively
controlling the rate at which supplemental liquid heating fluid is supply into
the reservoir 1000
(such as, for example, from the surface) for heating by the electrical heater
with the rate at
which the produced fluid is being produced. In some embodiments, for example,
the
predetermined high pressure is greater than 1750 kPa, such as, for example,
greater than 2000
kPa, such as, for example, greater than 2250 kPa. In some embodiments, for
example, the
predetermined high pressure is 2500 kPa.
[00125] In some embodiments, for example, the high pressure phase is then
suspended, and
pressure within the reservoir 1000 is then reduced to below the predetermined
low pressure. In
some embodiments, for example, the pressure reduction is effected at a rate of
decrease in
pressure within the reservoir 1000 of at least about 3 kPa per day, such as,
for example, at least
5 kPa per day, such as, for example, at least 1 kPa per day.
[00126] In some embodiments, for example, at the time of suspension of the
high pressure
phase, supplemental liquid heating fluid is being supplied into the reservoir
100, for heating by
the electrical heater, while the produced fluid is being produced.
In some of these
embodiments, for example, the reduction in pressure is effected by suspending
supplying of the
supplemental liquid heating fluid into the reservoir for heating by the
electrical heater. In other
ones of these embodiments, for example, the reduction in pressure is effected
by increasing the
rate of production of the produced fluid, while continuing supplying of the
supplemental liquid
heating fluid into the reservoir, for heating by the electrical heater, at the
same or substantially
the same rate. In other ones of these embodiments, for example, the decrease
in pressure is
effected by continuing production of the produced fluid at the same or
substantially the same
rate, while decreasing the rate at which supplemental liquid heating fluid is
being supplied into
the reservoir 1000 for heating by the electrical heater. In this respect, in
those embodiments
where supplemental liquid heating fluid is being supplied into the reservoir
100, for heating by
the electrical heater, while the produced fluid is being produced, the
pressure within the
reservoir is decreased by co-operatively modulating the rate at which the
supplemental liquid
heating fluid is being supplied to the reservoir 1000 for heating by the
electrical heater with
modulating of the rate at which the produced fluid is produced from the
reservoir 1000.
41
CA 2929924 2017-08-24

[00127] In some embodiments, for example, at the time of suspension of
the high pressure
phase, there is an absence of supplying of supplemental liquid heating fluid
into the reservoir
100, for heating by the electrical heater, while the produced fluid is being
produced. In some of
these embodiments, for example the reduction in pressure is effected by
increasing the rate of
production of the produced fluid.
[00128] In some embodiments, for example, the ratio of the predetermined
high pressure to
the predetermined low pressure is greater than 1.5, such as, for example,
greater than 2, such
as, for example, greater than 3..
[00129] In some embodiments, for example, the duration of the high
pressure phase is at
least one (1) month, such as, for example, at least three (3) months. In some
embodiments, for
example, the duration of the low pressure phase is at least one (1) month,
such as, for example,
at least three (3) months. In some embodiments, for example, the ratio of the
time duration of
the high pressure phase to the time duration of the low pressure phase is
between 1.5: 1 and
1:1.5, such as, for example, 1.2:1 to 1:1.2, such as, for example, 1.1:1 to
1:1.1. In some
embodiments, for example, the ratio is 1:1..
[00130] In some embodiments, for example, the high pressure phase and the low
pressure
phase define a cycle, and the cycle is repeated at least once, such as, for
example, at least
twice, such as, for example, at least three (3) times, such as, for example,
at least five (5) times.
[00131] During the increase in pressure, the rate of production is
reduced, but the produced
gaseous heating fluid is driven into the formation and has a greater tendency
to condense and
fill pore spaces within the reservoir to improve thermal conductivity.
[00132] During the reduction in pressure, the rate of production
increases.
[00133] In the above description, for purposes of explanation, numerous
details are set forth
in order to provide a thorough understanding of the present disclosure.
However, it will be
apparent to one skilled in the art that these specific details are not
required in order to practice
the present disclosure. Although certain dimensions and materials are
described for
implementing the disclosed example embodiments, other suitable dimensions
and/or materials
may be used within the scope of this disclosure. All such modifications and
variations, including
all suitable current and future changes in technology, are believed to be
within the sphere and
scope of the present disclosure.
42
CA 2929924 2017-08-24

Representative Drawing