US20180355706A1

US20180355706A1 - Processes for effecting hydrocarbon production from reservoirs having a low permeability zone by cooling and heating

Info

Publication number: US20180355706A1
Application number: US16/108,289
Authority: US
Inventors: Thomas Harding; Rudy STROBL
Original assignee: Nexen Energy ULC
Current assignee: CNOOC Petroleum North America ULC
Priority date: 2016-03-24
Filing date: 2018-08-22
Publication date: 2018-12-13
Also published as: WO2017161441A1; CA3010978C; CA3010978A1

Abstract

A process is provided for producing hydrocarbon material from a reservoir, including: cooling at least a portion of a low permeability zone within the reservoir with effect that water, disposed within the low permeability zone, freezes and expands, with effect that one or more flow paths are formed through the low permeability zone; mobilizing hydrocarbon material within the reservoir such that the mobilized hydrocarbon material is conducted through the low permeability zone via the one or more flow paths; and after the conduction of the mobilized hydrocarbon material through the low permeability zone via the one or more flow paths, producing the mobilized hydrocarbon material.

Description

RELATED APPLICATION

This application is a continuation in part of PCT International application no. PCT/CA2017/000067, filed 24 Mar. 2017, which claims all benefit, including priority of, U.S. Application Nos. 62/312,793, dated 24 Mar. 2016; and 62/312,801, dated 24 Mar. 2016.

FIELD

The present disclosure relates to improvements in production of hydrocarbon-comprising material from hydrocarbon reservoirs having low permeability zones.

BACKGROUND

Thermal enhanced oil recovery methods are used to recover bitumen and heavy oil from hydrocarbon reservoirs. The most dominant thermal enhanced oil recovery method being applied to oil sands reservoirs is steam-assisted gravity drainage (“SAGD”). However, SAGD performance suffers when oil sands reservoirs include zones of reduced permeability, such as shale barriers.

SUMMARY

In one aspect, there is provided a process for producing hydrocarbon material from a reservoir, comprising: cooling at least a portion of a low permeability zone within the reservoir with effect that water, disposed within the low permeability zone, freezes and expands, with effect that one or more flow paths are formed through the low permeability zone; mobilizing hydrocarbon material within the reservoir such that the mobilized hydrocarbon material is conducted through the low permeability zone via the one or more flow paths; and after the conduction of the mobilized hydrocarbon material through the low permeability zone via the one or more flow paths, producing the mobilized hydrocarbon material.
In another aspect, there is provided a process for producing hydrocarbon material from a reservoir, comprising: cooling at least a portion of a low permeability zone within the reservoir such that stress is reduced within the at least a portion of a low permeability zone; pressurizing the cooled portion of the low permeability zone with effect that one or more flow paths are formed through the low permeability zone; mobilizing hydrocarbon material within the reservoir such that the mobilized hydrocarbon material is conducted through the low permeability zone via the one or more flow paths; and after the conduction of the mobilized hydrocarbon material through the low permeability zone via the one or more flow paths, producing the mobilized hydrocarbon material.
In another aspect, there is provided a process for producing hydrocarbon material from a reservoir, comprising: heating at least a portion of a low permeability zone within the reservoir with effect that water, disposed within the low permeability zone, vaporizes and effects formation of one or more flow paths through the low permeability zone; mobilizing hydrocarbon material within the reservoir such that the mobilized hydrocarbon material is conducted through the low permeability zone via the one or more flow paths; and after the conduction of the mobilized hydrocarbon material through the low permeability zone via the one or more flow paths, producing the mobilized hydrocarbon material.
In another aspect, there is provided a process for producing hydrocarbon material from a reservoir, comprising: heating at least a portion of a low permeability zone within the reservoir; reducing pressure of the at least a portion of a low permeability zone, with effect that water, disposed within the low permeability zone, vaporizes and effects formation of one or more flow paths through the low permeability zone; mobilizing hydrocarbon material within the reservoir such that the mobilized hydrocarbon material is conducted through the low permeability zone via the one or more flow paths; and after the conduction of the mobilized hydrocarbon material through the low permeability zone via the one or more flow paths, producing the mobilized hydrocarbon material.
In another aspect, there is provided a process for producing hydrocarbon material from a reservoir, comprising: cooling at least a portion of a low permeability zone within the reservoir such that stress is reduced within the at least a portion of a low permeability zone; pressurizing the cooled portion of the low permeability zone with effect that one or more flow paths are formed through the low permeability zone; and receiving hydrocarbon material, that is conducted through the one or more of the flow paths, within a production well; and producing the received hydrocarbon material.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments will now be described, by way of example only, with reference to the attached figures, wherein:

FIG. 1 is a schematic illustration of one side of an embodiment of a system for implementing steam assisted gravity drainage (“SAGD”) for producing hydrocarbon material from a reservoir having a low permeability zone disposed between horizontal sections of a well pair;

FIG. 2 is a schematic illustration of one side of another embodiment of a system for implementing steam assisted gravity drainage (“SAGD”) for producing hydrocarbon material from a reservoir having a low permeability zone disposed between horizontal sections of a well pair, illustrating a dimensional attribute of the low permeability zone;

FIG. 3 is a schematic illustration of an end view of the embodiment illustrated in FIG. 2;

FIG. 4 is a schematic illustration of an end view of another embodiment of a system having two well pairs for implementing steam assisted gravity drainage (“SAGD”) for producing hydrocarbon material from a reservoir having a low permeability zone disposed between horizontal sections of one of the well pairs, illustrating a dimensional attribute of the low permeability zone;

FIG. 5 is a schematic illustration of one side of an embodiment of a system for implementing steam assisted gravity drainage (“SAGD”) for producing hydrocarbon material from a reservoir having a low permeability zone disposed above a horizontal section of the injection well of a well pair;

FIG. 6 is a schematic illustration of one side of another embodiment of a system for implementing steam assisted gravity drainage (“SAGD”) for producing hydrocarbon material from a reservoir having a low permeability zone disposed above a horizontal section of the injection well of a well pair, illustrating a dimensional attribute of the low permeability zone;

FIG. 7 is a schematic illustration of an end view of the embodiment illustrated in FIG. 6;

FIG. 8 is a schematic illustration of an end view of another embodiment of a system for implementing steam assisted gravity drainage (“SAGD”) for producing hydrocarbon material from a reservoir having a low permeability zone disposed above a horizontal section of the injection well of a well pair, illustrating a dimensional attribute of the low permeability zone; and

FIG. 9 is a schematic illustration of a steam chamber that has developed by operating a SAGD process using the system illustrated in any one of FIGS. 1 to 8.

DETAILED DESCRIPTION

The present disclosure relates to use of a production-initiating fluid for effecting production of hydrocarbon material from a hydrocarbon-containing reservoir 102 disposed within a subterranean formation below the earth's surface 12.
As used herein, the following terms have the following meanings:
“Hydrocarbon” is an organic compound consisting primarily of hydrogen and carbon, and, in some instances, may also contain heteroatoms such as sulfur, nitrogen and oxygen.
“Hydrocarbon material” is material that consists of one or more hydrocarbons.
“Heavy hydrocarbon material” is material that consists of one or more heavy hydrocarbons. A heavy hydrocarbon is a hydrocarbon that, at conditions existing with the hydrocarbon-containing reservoir, has a an API gravity of less than 26 degrees and a viscosity of greater than 20,000 centipoise. An exemplary heavy hydrocarbon material is bitumen.
A well, or sections of a well, can be characterized as “vertical” or “horizontal” even though the actual axial orientation can vary from true vertical or true horizontal, and even though the axial path can tend to “corkscrew” or otherwise vary. The term “horizontal”, when used to describe a section of a wellbore, refers to a horizontal or highly deviated wellbore section as understood in the art, such as, for example, a wellbore section having a longitudinal axis that is between 70 and 110 degrees from vertical.
The meaning of the terms “above” and “below” are not intended to be limited to mean, respectively, “directly above” and “directly below”, but are rather intended to define the elevation of one or more elements relative to the elevation of one or more other elements.
Referring to FIGS. 1 to 8, there is provided a system 100 for carrying out a process for producing hydrocarbon material from a hydrocarbon-containing reservoir 102. In some embodiments, for example, the hydrocarbon-containing reservoir includes an oil sands reservoir, and the hydrocarbon material includes heavy hydrocarbon material, such as bitumen.
The system 100 includes a well pair 101. The well pair 101 includes a pair of wells 104, 106. Each one of the wells 104, 106, independently, includes a respective horizontal section. The well 104 functions as a injection well and the well 106 functions as a production well. The injection well 104 injects production-initiating fluid to effect production of the hydrocarbon material via the production well 106.
In some embodiments, for example, a production-initiating fluid is injected via an injection string 112 that is disposed within the injection well 104, and the produced fluid is produced via a production string 114 that is disposed within the production well 106.
In some embodiments, for example, the injection string 112 includes a plurality of ports 112A for injecting production-initiating fluid, that is being conducted by the injection string, into the reservoir 102 at a plurality of injection points 104A within the reservoir 102. In some embodiments, for example, the plurality of injection points 104A are disposed along a reservoir interface 102A that defines the interface between the injection well 104 and the reservoir 102. In some embodiments, for example, the ports 112A are defined within a slotted liner of the injection string 112. In some embodiments, for example, the ports 112A are disposed within a horizontal section of the injection well 104.
In some embodiments, for example, the production string 114 includes a plurality of ports 114A for receiving fluid that is being conducted within the reservoir 102 in response to the injection of the production-initiating fluid. In some embodiments, for example, the ports 114A are defined within a slotted liner of the production string 114. In some embodiments, for example, the ports 114A are disposed within a horizontal section of the production well 106.
A hydrocarbon production process may be implemented via the well pair 101, so long as fluid communication is effected between the wells 104, 106 via a communication zone 110 (i.e. fluid is conductible (for example, by flowing)) such that the injected production-initiating fluid effects mobilization of the hydrocarbon material within the reservoir, and the mobilized hydrocarbon material is conducted to the production well 106 via the communication zone 110 for production via the production well 106. The conduction of the hydrocarbon material to the production well 106 is effected in response to an applied driving force (for example, application of a fluid pressure differential, or gravity, or both). In some embodiments, for example, the production-initiating fluid functions as a drive fluid effecting conduction (or transport) of hydrocarbon material to the production well 106. In some embodiments, for example, the production-initiating fluid functions as a heat transfer fluid, supplying heat to the hydrocarbon material, such that viscosity of the hydrocarbon material is sufficiently reduced (in such state, the hydrocarbon material is said to be mobilized), such that the hydrocarbon material may be conducted to the production well 106 by a driving force, such as, for example, a pressure differential or gravity. In some embodiments, for example, the production-initiating fluid functions as both a drive fluid and a heating fluid. In some embodiments, for example, the hydrocarbon material is produced along with some of the injected production-initiating fluid, such as, for example, production-initiating fluid that has heated the hydrocarbon material (as described above) and has become condensed, such that fluid that is being produced via the production well includes hydrocarbon material and condensed production-initiating fluid. While the wells 104, 106 are disposed in fluid communication through the communication zone 110, production-initiating fluid is injected into the reservoir 102 such that the hydrocarbon material is conducted to the well 106, via the communication zone 110, and produced through the well 106. In some embodiments, for example, the hydrocarbon material that is received by the well 106 is produced via the well 106 by artificial lift. In some embodiments, for example, the producing of the hydrocarbon material via the production well 106 is effected while the production-initiating fluid is being injected by the injection well 104. In this respect, in some embodiments, for example, the hydrocarbon production process is a continuous process.
In some embodiments, for example, the hydrocarbon production process includes a thermally-actuated gravity drainage-based hydrocarbon production process that is implemented via the well pair 101. In such embodiments, the horizontal section of the well 104 is vertically spaced from the horizontal section of the well 106, such that the horizontal section of the well 104 is disposed above the horizontal section of the well 106, such as, for example, by at least three (3) metres, such as, for example, by at least five (5) metres. In some embodiments, for example, the production-initiating fluid includes steam. A production phase (i.e. when hydrocarbon material is being produced via the well 106) of the thermally-actuated gravity drainage-based hydrocarbon production process occurs after the communication zone 110 has been established. The establishing of the communication zone 110 includes at least the establishing of interwell communication, through the interwell region 108, between the wells 104, 106. “Interwell communication”, in the context of a thermally-actuated gravity drainage-based hydrocarbon production process, describes a condition of the reservoir which permits hydrocarbon material within the reservoir 102, mobilized by heat supplied from the injected production-initiating fluid that is injected via the injection well 104, to be conducted, by at least gravity drainage, to the production well 106. In this respect, the interwell communication is established when the injected production-initiating fluid is able to communicate heat to hydrocarbon material within the reservoir such that the hydrocarbon material is mobilized, and the mobilized hydrocarbon material is then conducted, by at least gravity, through the interwell region 108, to the production well 106.
With respect to thermally-actuated gravity drainage-based hydrocarbon production processes being implemented via the well pair 101, in some of these embodiments, for example, initially, the reservoir 102 has relatively low fluid mobility (such as, for example, due to the fact that the hydrocarbon material within the reservoir 102 is highly viscous) such that the communication zone 110 is not present. In order to enable the injected production-initiating fluid (being injected through the injection well 104) to promote the conduction of the reservoir hydrocarbons, within the reservoir 102, to the production well 106, the communication zone 110 must be established. This establishing of the communication zone 110 includes establishing interwell communication between the wells 104, 106 through the interwell region 108. By establishing the interwell communication, the conduction of the mobilized hydrocarbon material, through the interwell region 108, is enabled such that the mobilized hydrocarbon material is collected within the production well 106. The interwell communication may be established during a “start-up” phase of the thermally-actuated gravity drainage-based hydrocarbon production process. In some embodiments, for example, during the start-up phase, the interwell region 108 is heated. In some embodiments, for example, the heat is supplied to the interwell region 108 by effecting circulation of a start-up phase fluid (such as steam, or a fluid including steam) in one or both of the wells 104, 106. The heat that is supplied to the interwell region 108 heats the reservoir hydrocarbons within the interwell region 108, thereby reducing the viscosity of the reservoir hydrocarbons. Eventually, the interwell region 108 becomes heated to a temperature such that the hydrocarbon material is sufficiently mobile (i.e. the hydrocarbon material has been “mobilized”) for displacement to the production well 106 by at least gravity drainage. In this respect, eventually, sufficient hydrocarbon material becomes mobilized, such that this space (the interwell region 108), previously occupied by immobile, or substantially immobile, hydrocarbon material, is disposed to communicate fluid between the injection well 104 and the production well 106 in response to a driving force, such that at least hydrocarbon material is conductible through this space in response to the driving force. Upon the interwell region becoming disposed to communicate fluid between the injection well 104 and the production well 106 in response to a driving force, such that at least hydrocarbon material is conductible through this space in response to the driving force, the interwell communication, between the wells 104, 106, is said to have become established. The development of this interwell communication signals completion of the start-up phase and conversion to a production phase.
During the production phase of a thermally-actuated gravity drainage-based hydrocarbon production process, the communication zone 110 effects fluid communication between the production-initiating fluid, being injected through the injection well 104, with hydrocarbon material within the reservoir, such that the injected production-initiating fluid is conducted through the communication zone 110 and becomes disposed in heat transfer communication with hydrocarbon material within the reservoir such that the hydrocarbon material becomes heated. When sufficiently heated such that its viscosity becomes sufficiently reduced, the hydrocarbon material becomes mobilized, and, in this respect, the hydrocarbon material is able to be conducted, by at least gravity drainage (the conduction may also, for example, be promoted by a pressure differential that is established between the injected production initiating fluid and the production well 106, which may also, in some embodiments, be characterized as a “drive process” mechanism), through the communication zone 110, to the production well 106, and subsequently produced from the production well 106 by artificial lift, such as by a pump. During the production phase, while the production-initiating fluid is being injected into the communication zone 110 via the injection well 104, as the mobilized hydrocarbon material drains to the production well 106, space previously occupied by the hydrocarbon material within the reservoir becomes occupied by the injected production-initiating fluid, thereby exposing a fresh hydrocarbon material surface for receiving heat from the production-initiating fluid (typically, by conduction). This repeated cycle of heating, mobilization, drainage, and establishment of heat transfer communication between the production-initiating fluid and a freshly exposed hydrocarbon material source results in the growth of the communication zone 110, with the freshly exposed hydrocarbon material being disposed along an edge of the communication zone 110. Referring to FIG. 9, in some embodiments, for example, the communication zone 110 includes a “vapour chamber”. In some embodiments, for example, the vapour chamber may also be referred to as a “steam chamber”. In some embodiments, for example, the growth of the communication zone 110 is upwardly, laterally, or both, and, typically, extends above the horizontal section of the injection well 104.
In some embodiments, for example, where, in implementing the thermally-actuated gravity drainage-based hydrocarbon production process, the production-initiating fluid includes steam, the process that is effecting this production is described as “steam-assisted gravity drainage” or “SAGD”. In some embodiments, for example, the communication zone 110 includes a vapour chamber, such as, for example, a “steam chamber”. During SAGD, the conduction of the mobilized hydrocarbon material to the production well 106 is accompanied by condensed steam (i.e. water), whose condensation is effected by at least heat loss to the hydrocarbon material (which effects the mobilization of the hydrocarbon material).
In some embodiments, for example, the reservoir includes a low permeability zone. The low permeability zone 116 is a zone whose absolute permeability is less than 1000 millidarcies, such as, for example, less than 100 millidarcies, such as, for example, less than 10 millidarcies.
Examples of low permeability zones 116 include baffles and barriers. These include barrier or baffle layers of shale, breccia, inclined heterolithic strata, mud, and mudstone. It will be understood that such layers are formed by natural geological activity and can be of various shapes and configuration disposed above, below or between the injection well 104 and the production well 106. In the drawings, the low permeability zones 116 are shown as simple geometric shapes for simplicity of explanation only and those skilled in the relevant art will recognize that great variations in shape, configuration and permeability will exist in such naturally formed geological layers.
In some embodiments, for example, the low permeability zone 116 has a dimension of at least 10 metres, such as, for example, 25 metres, such as, for example, at least 35 metres. In some embodiments, for example, the dimension is a width.
In some embodiments, for example, the low permeability zone 116 is relatively thin, and, in this respect, in some embodiments, for example, is characterized by a maximum thickness of less than 5 centimetres.
In some embodiments, for example, at least a continuous portion of the low permeability zone 116 is disposed within a horizontal plane within the reservoir 102, wherein the horizontal plane-disposed continuous portion of the low permeability zone 116 is characterized by an area of at least 100 square metres.
In some embodiments, for example, the low permeability zone 116 is disposed between the horizontal sections of the wells 104, 106, such as, for example, in the interwell region 108.
Referring to FIGS. 2 and 3, in some embodiments, for example, at least a continuous portion of the low permeability zone 116 is disposed between the horizontal sections of the wells 104, 106, and the continuous portion has an axis “A1”, and the axis “A1” has a length “L1” of at least 10 metres, such as, for example, at least 50 metres, such as, for example, at least 100 metres.
Referring to FIG. 4, in some embodiments, for example, at least a continuous laterally-extending portion of the low permeability zone 116 is disposed between the horizontal sections of the wells 104, 106 and is also extending towards another well pair 201 and across at least ⅓ of a spacing distance “SD” between the well pairs 101, 102. In some embodiments, for example, the at least a continuous laterally-extending portion of the low permeability zone 116 extends from between the well pair 101 and towards the another well pair 201 by a distance “D1” of at least 25 metres, such as, for example, at least 35 metres.
Referring to FIG. 5, in some embodiments, for example, the low permeability zone 116 is disposed above both of the horizontal sections of the wells 104, 106.
Referring to FIGS. 6 and 7, in some embodiments, for example, at least a continuous portion of the low permeability zone 116 includes an axis “A2”, and the axis “A2” of the at least a continuous portion is disposed above, and in vertical alignment with, a longitudinal axis “A3” of the horizontal section of the well 104, and has a length “L2” of at least 10 metres, such as, for example, at least 50 metres, such as, for example, at least 100 metres.
Referring to FIG. 8, in some embodiments, for example, at least a continuous portion of the low permeability zone 116 is disposed above the horizontal section of the well 104 and at a height “H”, above the bottom of the reservoir, that is less than 50% of the total height “TH” of the reservoir. In some embodiments, for example, at least a continuous portion of the low permeability zone 116 is disposed above the horizontal section of the well 104 and at a height “H” of less than 35 metres (such as, for example, less than 25 metres) above the bottom of the reservoir.
There is provided a process for forming a flow path within a low permeability zone 116, for effecting flow communication within the reservoir 102, via the flow path, between a communication-interfered zone 118A and a wellbore. The low permeability zone 116 is disposed between the wellbore and the communication-interfered zone 118A. In some embodiment, for example, the low permeability zone 116 functions as an impediment for conduction of fluid material into and from the communication-interfered zone 118A and a wellbore, and the flow communication effected by the flow path is intended to enable such conduction. In some embodiments, for example, the impediment includes an impediment to a vertical flow of fluid. In some embodiments, for example, the wellbore is defined as an injection well 104 of a SAGD system. In some embodiments, for example, the wellbore is defined as a production well 106 of a SAGD system.
In some embodiments, for example, the process for forming a flow path within a low permeability zone 116 includes cooling of at least a portion of the low permeability zone 116.
In some embodiments, for example, the cooling of the at least a portion of the low permeability zone 116 is such that the rate of decrease of temperature within the at least a portion of the low permeability zone 116 is at least one (1) degrees Celsius per hour, such as, for example, at least two (2) degrees Celsius per hour.
In some embodiments, for example, the cooling is effected by injecting a cold fluid (i.e. a fluid having a temperature that is less than the temperature of the low permeability zone) with effect that the injected cold fluid becomes disposed in thermal communication with the low permeability zone 116. In some embodiments, for example, the injecting includes circulating a cold fluid within one or both of the wells 104, 106, in which case, the cooling is effected by conduction of heat from the subterranean formation between the injection well 104 and the low permeability zone 116. In some embodiments, for example, the low permeability zone 116 is spaced apart from at least one of the wells 104, 106, through which the cold fluid is being circulated, by a minimum distance of less than 15 metres, such as, for example, less than 10 metres.
The low permeability zone 116 as referred to herein is the barrier that intended to be fractured or broken in order to allow bitumen and fluids to pass through the zone 116 along fractures. The cooled or frozen region of the reservoir extends from the injection well 104 (i.e. the upper well 104 in the injection- production well 104, 106 pair through which cold fluid is circulated in order to cool or freeze the formation) into the formation to a distance that is dependent on the length of time of cooling, the temperature of the cooling fluid and the thermal conductivity of the formation. The entire cooled or frozen region of the reservoir extends further than merely into the low permeability zone 116 (i.e. shale or low permeability barrier) but always includes the shale or permeability barrier 116. The cold fluid injected into the reservoir via the injection well 104 creates a cooled region that ideally extends some distance above and below the low permeability zone 116 (shale barrier). In the case where the low permeability zone 116 (shale) is located above the injector well 104, there exists a warmer reservoir zone above the cooled zone (which includes the low permeability zone 116) located between the cap rock of the reservoir and the cooled zone. Thus it is in this warmer zone of the reservoir that the original temperature of the reservoir is maintained and is not effected by cooling. It is in the warmer zone that is beyond the range of cooling that the upward propagation of the fracture is be truncated or impeded from forming. The truncation of fractures in the warmer zone of the reservoir allows higher pressures to be used in the injection well 104 because the fracturing of the cap rock layer and resultant escape of cooling fluid, gas or bitumen is also impeded.
In some embodiments, for example, the temperature of the cold fluid is less than minus 50 degrees Celsius.
In some embodiments, for example, the rate of cooling of the at least a portion of the low permeability zone 116 is at least 0.03 degrees Celsius per metre per day, such as, for example, 0.04 degrees Celsius per metre per day.
In some embodiments, for example, the cold fluid includes any one, or any combination of, the fluids selected from the group consisting of: liquid nitrogen, liquid CO2 and liquid hydrocarbon solvents such as propane, butane, and natural gas condensate.
In some embodiments, for example, the cooling of the low permeability zone 116 is effected prior to the production phase. In some embodiments, for example, the cooling of the low permeability zone 116 is effected prior to the heating of the interwell region 108 during the SAGD start-up phase. In this respect, in some embodiments, for example, after the cooling, a SAGD start-up phase is implemented, followed by a SAGD production phase.
Cooling of the low permeability zone 116 relieves stresses within the low permeability zone 116. Because the heat sink is within a well through which cold fluid is being conducted, as a necessary incident, such cooling also relieves the stresses in an intermediate region of the subterranean formation, between a well through which cold fluid is being conducted (e.g. the injection well) 104 and the low permeability zone 116, thereby conditioning the low permeability zone 116, as well as the intermediate formation region between the well and the low permeability zone 116, such that both of the intermediate formation region and the low permeability zone 116 are disposed for crack formation at lower applied pressures.
In some embodiments, for example, the cooling of the low permeability zone 116 is with effect that a temperature decrease is effected to at least a portion of the low permeability zone 116, and with effect that one or more cracks are formed within the low permeability zone 116.
In some embodiments, for example, the cooling of the low permeability zone 116 is with effect that a temperature decrease is effected to at least a portion of the low permeability zone 116 to below a predetermined temperature. In some embodiments, for example, the cooling of the low permeability zone 116 is such that at least a portion of the low permeability zone 116 becomes disposed at a temperature that is below the freezing point of water at the pressure within the low permeability zone 116.
In this respect, in some embodiments, for example, the cooling of the low permeability zone is with effect that at least a portion of the low permeability zone 116 becomes disposed at a temperature that is below the freezing point of water at the pressure within the low permeability zone and effects freezing of water within the at least a portion of the low permeability zone. Because water expands upon freezing, one or more cracks are formed in the low permeability zone 116 in response to the freezing of the water, thereby defining one or more flow paths (cracks) for conducting of fluid material within the low permeability zone, such as, for example, conducting of a heating fluid (such as, for example, a start-up phase fluid or a production-initiating fluid), or conducting of mobilized hydrocarbon material. The stresses in the cooled low permeability zone 116 is reduced, however stresses in the adjacent non-cooled portions of the reservoir remain unaffected. As a consequence crack propagation within the cooled low permeability zone 116 can be accomplished using pressurized fluid at a lower pressure, thereby reducing energy costs and also reducing the risk of fracturing the overlying cap rock layer. When a fracture propagates from the cooled low permeability zone 116 towards an adjacent warmer uncooled portion of the reservoir, the warmer portion is relatively more resistant to crack or fracture propagation since stresses are maintained at a higher level in the warmer portion. In some embodiments, for example, the entirety of the low permeability zone 116 becomes disposed at a temperature that is below the freezing point of water at the pressure within the low permeability zone, in response to the cooling.
In some embodiments, for example, the process for forming a flow path within a low permeability zone 116 includes cooling the low permeability zone 116 (such as, for example, in accordance with any one of the embodiments, as above-described), and, after the low permeability zone 116 has been cooled, pressurizing the cooled low permeability zone 116. As explained above, the cooling of the low permeability zone 116 relieves stresses within the low permeability zone 116, as well as an intermediate formation region between the well (which is functioning as a heat sink) and the low permeability zone 116, thereby conditioning both of the intermediate formation region and the low permeability zone 116 for crack formation at lower applied pressures. Co-operatively, pressurized material is injected into the reservoir 102, for pressurizing the cooled low permeability zone 116, and thereby effecting formation of one or more cracks within the cooled low permeability zone 116. However in the adjacent warmer uncooled portion of the reservoir, the warmer portion is relatively more resistant to crack or fracture propagation and crack propagation is terminated within the warmer uncooled portion of the reservoir, where stresses are unaffected. The ability to control crack propagation by controlling the zone that is cooled, allows the use of higher pressure fracturing fluid because the risk of fracturing and penetrating the overlying cap rock layer is reduced or eliminated. Cracks are propagated only through the cooled low permeability zone 116 where stresses are lowered and the warmer uncooled portion of the reservoir having higher stresses tends to resist crack propagation thereby limiting and controlling the formation of cracks into zones where cracks would be undesirable, such as into cap rock layers. In some embodiments, for example, the pressurized material is supplied via a wellbore, such as the injection well 104, or the production well 106, or both, and injected into the reservoir 102 for pressurizing the low permeability zone 116. In some embodiments, for example, the pressurizing is with effect that the low permeability zone becomes disposed at a pressure of at least original reservoir pressure, such as, for example, at least 105% of original reservoir pressure, such as, for example, at least 110% of original reservoir pressure. In some of these embodiments, for example, the pressurizing is with effect that the low permeability zone 116 becomes disposed at a pressure of up to the maximum allowable pressure of the reservoir 102 (the pressure that is determined to maintain integrity of the cap rock above the reservoir)
In some embodiments, for example, the pressurized material is injected at an injection pressure of between the original reservoir pressure and the maximum allowable pressure of the reservoir 102. In some embodiments, for example, the injection pressure is the lowest pressure (above the original reservoir pressure) at which formation parting is achievable following cooling of the reservoir 102 (such as, for example, in close proximity to a well, such as the injection well 104), such cooling resulting in a reduction in reservoir effective stress from such cooling.
In some embodiments, for example, the duration of the injecting of the pressurized material is at least two (2) minutes, such as, for example, at least five (5) minutes, such as, for example, at least 20 minutes, such as for example, at least one (1) hour, such as, for example, at least two (2) hours, such as, for example, at least five (5) hours, such as, for example, at least one (1) day, such, as for example, at least two (2) days, such as, for example, at least five (5) days.
In some embodiments, for example, the pressurized material includes a fluid. In some embodiments, for example, the pressurized material includes a liquid including water. In some embodiments, for example, the liquid includes water and chemical additives. In other embodiments, for example, the pressurized material is a slurry including water, proppant, and chemical additives. Exemplary chemical additives include acids, sodium chloride, polyacrylamide, ethylene glycol, borate salts, sodium and potassium carbonates, glutaraldehyde, guar gum and other water soluble gels, citric acid, and isopropanol. In some embodiments, for example, the pressurized material is supplied to effect hydraulic fracturing of the reservoir.
In some embodiments, for example, the process for forming a flow path within a low permeability zone 116 includes heating the low permeability zone 116.
In some of these embodiments, for example, the heating is effected by circulating a heating fluid (i.e. a fluid having a temperature that is greater than the temperature of the low permeability zone) within one or both of the wells 104, 106 (such as, for example, during the SAGD start-up phase), with effect that the circulated heating fluid becomes disposed in thermal communication with the low permeability zone 116.
In some embodiments, for example, the heating fluid includes steam, and may also include steam admixed with a solvent that is soluble within the hydrocarbon material that is disposed within the reservoir 102. In some embodiments, for example, the heating fluid includes glycerine. In some embodiments, for example, the heating fluid includes diethanolamine (DEA). In some embodiments, for example, the heating fluid is the start-up phase fluid. In some embodiments, for example, the low permeability zone 116 is spaced apart from at least one of the wells 104, 106, through which the heating fluid is being circulated, by a minimum distance of less than 15 metres, such as, for example, less than 10 metres.
In some embodiments, for example, the heating is effected by injecting (such as, for example, during the SAGD production phase) a heating fluid (i.e. a fluid having a temperature that is greater than the temperature of the low permeability zone) into the reservoir 102 with effect that the injected heating fluid becomes disposed in thermal communication with the low permeability zone 116. In some of these embodiments, for example, the thermal communication is established by mobilizing hydrocarbon material between the injection well 104 and the low permeability zone 116 (such as by, for example, implementing the production phase of the thermally-actuated gravity drainage-based process, as above-described) such that the mobilized hydrocarbon material is conducted to the production well 106, and the space previously occupied by immobile, or substantially immobile, hydrocarbon material, is disposed to conduct the injected heating fluid from one or both of the wells 104, 106, such that the injected heating fluid becomes disposed in thermal communication with the low permeability zone 116. In some embodiments, for example, the heating fluid includes steam, and may also include steam admixed with a solvent that is soluble within the hydrocarbon material that is disposed within the reservoir. In some embodiments, for example, the heating fluid is the production-initiating fluid. In some embodiments, for example, the low permeability zone 116 is spaced apart from at least one of the wells 104, 106, through which the heating fluid is being injected, by a minimum distance of less than 15 metres, such as, for example, less than 10 metres.
In some embodiments, for example, the heating of the low permeability zone 116 includes heating that is effected by electrical heating. In some embodiments, for example, the electrical heating can be effected by a resistive electric heater or by electromagnetic energy propagation into the formation. In some embodiments, for example, the electrical heating is effected by an electrical heater disposed in one or both of the wells 104, 106. In some embodiments, for example, the low permeability zone 116 is spaced apart from at least one of the wells 104, 106, through which the electrical heater is disposed, by a minimum distance of less than 15 metres, such as, for example, less than 10 metres.
In some embodiments, for example, the heating of the low permeability zone 116 includes heating that is effected by in-situ combustion. An exemplary in-situ combustion process is SAGDOX™.
In some embodiments, for example, the heating of the low permeability zone 116 is effected prior to the SAGD production phase. In some embodiments, for example, the heating of the low permeability zone 116 is effected after hydrocarbon material has been produced during the SAGD production phase.
In some embodiments, for example, the heating of the low permeability zone 116 is effected prior to the heating of the interwell region 108 during the SAGD start-up phase.
In some embodiments, for example, the heating of the low permeability zone 116 is effected during the heating of the interwell region 108 during the SAGD start-up phase, in which case, in some embodiments, for example, the heating fluid includes the start-up phase fluid.
In some embodiments, for example, the heating of the low permeability zone 116 is effected during the SAGD production phase, in which case, in some embodiments, for example, the heating fluid includes production-initiating fluid.
In some embodiments, for example, the heating of the low permeability zone 116 is with effect that a temperature increase is effected to at least a portion of the low permeability zone 116, and with effect that one or more cracks are formed within the low permeability zone 116. In some embodiments, for example, the heating of the low permeability zone 116 is with effect that a temperature increase is effected to at least a portion of the low permeability zone 116 to above a predetermined temperature. In some embodiments, for example, the heating of the low permeability zone 116 is such that at least a portion of the low permeability zone 116 becomes disposed at a temperature of at least steam temperature at the pressure within the low permeability zone 116. By heating the low permeability zone 116 such that at least a portion of the low permeability zone 116 becomes disposed at a temperature of at least steam temperature at the pressure within the low permeability zone 116, water within the low permeability zone 116 is vaporized, expands, and effects crack formation within the low permeability zone.
In some embodiments, for example, the rate of heating necessary to effect mechanical failure within the low permeability zone 116, and consequent crack formation, is dependent on the permeability of the low permeability zone 116: the lower the permeability, the low the rate of heating that is required. This is because the fluid (in some embodiments, for example, a fluid including water), being vaporized within the low permeability zone 116, will escape from the low permeability zone 116 at a rate that is fast enough such that pressure increase within the low permeability zone 116 is not sufficient to effect mechanical failure and consequent crack formation. In this respect, with zones of lower permeability (such as for low permeability zones with permeability less than 5 millidarcies), a faster rate of heating is required to enable a pressure increase within the low permeability zone 116 that is sufficient to effect mechanical failure and consequent crack formation. In some embodiments, for example, the heating of the at least a portion of the low permeability zone 116 is such that the rate of increase of temperature within the at least a portion of the low permeability zone 116 is at least one (1) degrees Celsius per hour, such as, for example, at least two (2) degrees Celsius per hour.
In some embodiments, for example, the duration of the heating is at least one (1) minute, such as, for example, at least two (2) minutes, such as, for example, at least five (5) minutes, such as, for example, at least ten (10) minutes, such as, for example, at least one (1) hour, such as, for example, at least five (5) hours, such as, for example, at least one (1) day, such as, for example, at least two (2) days, such as, for example, at least five (5) days. In some embodiments, for example, the duration of the heating of the at least a portion of the low permeability zone 116 is at least 30 days. In some embodiments, for example, the duration of the heating of the at least a portion of the low permeability zone 116 is between 30 days and 90 days. The duration depends on the distance of the at least a portion of the low permeability zone 116 from the heat source.
In some embodiments, for example, the process for forming a flow path within a low permeability zone 116 includes heating the low permeability zone 116 (such as, for example, in accordance with any one of the embodiments, as above-described), and, after the low permeability zone 116 has been heated, effecting a reduction in pressure of the heated low permeability zone 116. The heating of at least a portion of the low permeability zone 116, and after the heating, the effecting a reduction in pressure of the low permeability zone 116, co-operate with effect that water within the low permeability zone 116 is vaporized, expands, and effects crack formation within the low permeability zone 116.
The rate of heating necessary to cause mechanical failure of the low permeability zone and the formation of cracks is dependent on the permeability of the low permeability zone, the lower the permeability, the lower the rate of heating required. This is because the fluid being vaporized within the low permeability zone, in some instances water, will escape from the low permeability zone and not cause the pressure to increase enough to result in formation of cracks. For low permeability zones with permeability less than 5 millidarcies, a rate of heating of at least one degree Celsius per hour is required, and rates higher, such as 2° C./hr would be preferred. In some embodiments, for example, the heating of the at least a portion of the low permeability zone 116 is such that the rate of increase of temperature within the at least a portion of the low permeability zone 116 is at least one (1) degrees Celsius per hour, such as, for example, at least two (2) degrees Celsius per hour. The temperature of the low permeability zone must reach the saturated steam temperature at the reservoir pressure so that liquid water contained within the low permeability zone will begin to vaporize immediately as the pressure is reduced.
In some embodiments, for example, the heating of at least a portion of the low permeability zone 116 is with effect that the temperature of the at least a portion of the low permeability zone 116 is between 200 degrees Celsius and 240 degrees Celsius.
In some embodiments, for example, the duration of the heating is at least one (1) minute, such as, for example, at least two (2) minutes, such as, for example, at least five (5) minutes, such as, for example, at least ten (10) minutes, such as, for example, at least one (1) hour, such as, for example, at least five (5) hours, such as, for example, at least one (1) day, such as, for example, at least two (2) days, such as, for example, at least five (5) days. In some embodiments, for example, the duration of the heating of the at least a portion of the low permeability zone 116 is at least 30 days. In some embodiments, for example, the duration of the heating of the at least a portion of the low permeability zone 116 is between 30 days and 90 days. The duration depends on the distance of the at least a portion of the low permeability zone 116 from the heat source.
After the temperature increase has been effected by the heating, a reduction in pressure of the low permeability zone 116 is effected. The reduction in pressure is with effect that vaporized water is produced, and such vaporized water is derived from water within the low permeability zone 116. The produced vaporized water is disposed at a sufficient pressure to induce sufficient stress within the rock of the low permeability zone 116 to effect formation of one or more cracks within the low permeability zone 116. In some embodiments, for example, the rate at which the pressure reduction is effected is a function of the permeability of the low permeability zone 116.
In some embodiments, for example, the reduction in pressure is at least 50 psi over a period of time of 48 hours, such as, for example, at least 100 psi over a period of time of 48 hours.
When the heating is effected by the circulating of heating fluid within one or both of the wells 104, 106 (such as, for example, during the SAGD start-up phase), in some of these embodiments, for example, the reduction in pressure of the low permeability zone 116 is effected by suspending the circulation of the heating fluid.
When the heating is effected by electrical heating, in some of these embodiments, for example, the reduction in pressure of the low permeability zone 116 is effected by producing hydrocarbon material via one or both of the wells 104, 106.
When the heating is effected by injecting of heating fluid into the reservoir 102, in some of these embodiments, for example, the reduction in pressure of the low permeability zone 116 is effected by suspending supplying of the heating fluid into the communication zone 110.
When the heating is effected by injecting (such as, for example, via the injection well 104) of heating fluid (such as, for example, production-initiating fluid) into the reservoir 102 (such as, for example, the communication zone 110), while producing fluid (in some embodiments, for example, the fluid includes hydrocarbon material) from the reservoir 102 (such as, for example, from the communication zone 110, and via the well 106), in some of these embodiments, for example, the reduction in pressure of the low permeability zone 116 is effected by increasing the rate of production of fluid from the reservoir 102, while continuing the injecting of the heating fluid to the reservoir 102 at the same or substantially the same molar rate.
When the heating is effected by injecting (such as, for example, via the injection well 104) of heating fluid (such as, for example, production-initiating fluid) into the reservoir 102 (such as, for example, the communication zone 110), while producing fluid (in some embodiments, for example, the fluid includes hydrocarbon material) from the reservoir 102 (such as, for example, from the communication zone 110, and via the well 106), in some of these embodiments, for example, the reduction in pressure of the low permeability zone 116 is effected by continuing production of fluid from the reservoir 102 at the same or substantially the same rate, while decreasing the rate at which the heating fluid is supplied to the reservoir 102.
When the heating is effected by injecting (such as, for example, via the injection well 104) of heating fluid (such as, for example, production-initiating fluid) into the reservoir 102 (such as, for example, the communication zone 110), while producing fluid (in some embodiments, for example, the fluid includes hydrocarbon material) from the reservoir 102 (such as, for example, from the communication zone 110, and via the well 106), in some of these embodiments, for example, the reduction in pressure of the low permeability zone 116 is effected by, co-operatively, modulating the rate at which the heating fluid is supplied to the reservoir 102 and modulating the rate at which fluid is produced from the reservoir 102. In this respect, the modulating of the rate at which the heating fluid is supplied to the reservoir 102 and the modulating the rate at which fluid is produced from the reservoir 102 co-operate with effect that the reduction in pressure of the low permeability zone 116 is effected.
In some embodiments, for example, the process for forming a flow path within a low permeability zone 116 is effected in response to detection of the low permeability zone 116. In some of these embodiments, for example, such detection is effected only after the SAGD start-up phase has commenced and prior to the SAGD production phase. In some embodiments, for example, such detection is effected only after the SAGD production phase has commenced. In some embodiments, for example, the detection of the low permeability zone 116 is inferred from temperature conformance data, drilling logs, or petrophysical logs.
In some embodiments, for example, the low permeability zone 116 is disposed within the interwell region 108 (between the horizontal sections of the wells 104, 106), with effect that a communication-interfered zone 118A is disposed between the low permeability zone 116 and the horizontal section of the production well 106, and a communication-interfered zone 118B is disposed between the low permeability zone 116 and the horizontal section of the injection well 104. The low permeability zone 116 is disposed for at least interfering with fluid communication, and, in some embodiments, for blocking flow communication, between: (i) the injection well 104 and the communication-interfered zone 118A, and (ii) the production well 106 and the communication-interfered zone 118B. In this respect, the low permeability zone 116 is disposed for at least interfering with, and in some embodiments, blocking, conduction of fluid material between: (i) the injection well 104 and the communication-interfered zone 118A, and (ii) the production well 106 and the communication-interfered zone 118B, and, therefore, functions as a vertical impediment to such conduction.
During the start-up phase, the low permeability zone 116 is disposed for at least interfering with, and in some embodiments, blocking, conduction of heat from start-up phase fluid, that is being circulated by the wells 104, 106, to the communication-interfered zones 118A, 118B, thereby at least interfering with mobilization of the hydrocarbon material within the communication-interfered zones 118A, 118B by the start-up phase fluid. Also during the start-up phase, the low permeability zone 116 is disposed for at least interfering with, and in some embodiments, blocking, conduction of mobilized hydrocarbon material from the communication-interfered zone 118B to the production well 106, and thereby impeding the development of a flow-communicating space (i.e. interwell communication), that has been previously occupied by immobile, or substantially immobile, hydrocarbon material, for communicating flow between the injection well 104 and the production well 106 in response to a driving force, such that at least hydrocarbon material is conductible through this space in response to the driving force (i.e. interwell communication). During the production phase, the low permeability zone 116 is disposed for at least interfering with, and in some embodiments, blocking, conduction of the mobilized hydrocarbon material that is draining towards the production well 106 from the vapour (e.g. steam) chamber, via the communication-interfered zone 118B, and thereby interfering with production.
The one or more cracks that are formed, in accordance with any one of the processes described above, effect flow communication through the low permeability zone 116, enabling conduction of fluid material within the interwell region 108 via the low permeability zone 116. In this respect, in some embodiments, for example, the crack formation is with effect that there is an increase in absolute permeability of the low permeability zone 116 by at least 200%, such as, for example, by at least 2500%, such as, for example, at least 5000%.
In this respect, the one or more cracks can effect: (i) conduction of start-up phase fluid from the well 104 to the communication-interfered zone 118A, or (ii) conduction of start-up phase fluid from the well 106 to the communication-interfered zone 118B, or both of (i) and (ii), thereby facilitating heating of one or both of the communication-interfered zones 118A, 118B, during the start-up phase. Also, the one or more cracks can effect conduction of mobilized hydrocarbon material from the communication-interfered zone 118B to the well 106, during the start-up phase, thereby facilitating the establishment of interwell communication, as above-described. Further, the one or more cracks can effect conduction of mobilized hydrocarbons from the communication-interfered zone 118B to the well 106 during the production phase, thereby facilitating an increased rate of production of hydrocarbon material from the reservoir.
In some embodiments, for example, the low permeability zone 116 is disposed above the horizontal sections of the injection well 104, and, therefore, above the horizontal section of the production well (see FIG. 5), with effect that the low permeability zone 116 is disposed between a communication-interfered zone 1182 and the horizontal section of the production well 106, and also between the communication interfered zone 1182 and the horizontal section of the injection well 104. In this respect, the low permeability zone 116 is disposed for at least interfering with flow communication, and, in some embodiments, for blocking flow communication, between: (i) the injection well 104 and the communication-interfered zone 1182, and (ii) the production well 106 and the communication-interfered zone 1182. In this respect, the low permeability zone 116 is disposed for at least interferes with, and in some embodiments, blocking, conduction of fluid material between: (i) the injection well 104 and the communication-interfered zone 1182, and (ii) the production well 106 and the communication-interfered zone 1182, and, therefore, functions as a vertical impediment to such conduction.
During the production phase, the low permeability zone 116 is disposed for at least interfering with, and in some embodiments, blocking, conduction of the production-initiating fluid to the communication-interfered zone 1182 (disposed above the low permeability zone 116) for effecting heating and mobilization of hydrocarbon material disposed within the communication-interfered zone 1182. In this respect, in some embodiments, for example, the low permeability zone 116 functions as an impediment to the growth of the vapor (or steam) chamber. As well, even if the production-initiating fluid is able to migrate above the low permeability zone 116 and into the communication-interfered zone 1182, the low permeability zone 116 is disposed for at least interfering with, and in some embodiments, blocking, conduction of the mobilized hydrocarbon material that is draining from the communication-interfered zone 1182 (e.g. the steam chamber) to the production well 106, and thereby interfering with production.
In this respect, the one or more cracks, that are formed in accordance with any one of the processes described above, can effect conduction of the production-initiating fluid from the injection well 104 to the communication-interfered zone 1182 during the production phase, thereby facilitating mobilization of the hydrocarbon material within the reservoir, and enabling growth of the vapour (e.g. steam) chamber. Also, the one or more cracks can effect conduction of the mobilized hydrocarbons from the communication-interfered zone 1182 to the production well 106 during the production phase, thereby facilitating an increased rate of production of hydrocarbon material from the reservoir.
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. All references mentioned are hereby incorporated by reference in their entirety.

Claims

1. A process for producing hydrocarbon material from a reservoir, comprising:

cooling at least a portion of a low permeability zone within the reservoir with effect that water, disposed within the low permeability zone, freezes and expands, with effect that one or more flow paths are formed through the low permeability zone;

mobilizing hydrocarbon material within the reservoir such that the mobilized hydrocarbon material is conducted through the low permeability zone via the one or more flow paths; and

after the conduction of the mobilized hydrocarbon material through the low permeability zone via the one or more flow paths, producing the mobilized hydrocarbon material.

2. A process for producing hydrocarbon material from a reservoir, comprising:

cooling at least a portion of a low permeability zone within the reservoir such that stress is reduced within the at least a portion of a low permeability zone;

pressurizing the cooled portion of the low permeability zone with effect that one or more flow paths are formed through the low permeability zone;

3. A process for producing hydrocarbon material from a reservoir, comprising:

heating at least a portion of a low permeability zone within the reservoir with effect that water, disposed within the low permeability zone, vaporizes and effects formation of one or more flow paths through the low permeability zone;

4. A process for producing hydrocarbon material from a reservoir, comprising:

heating at least a portion of a low permeability zone within the reservoir;

reducing pressure of the at least a portion of a low permeability zone, with effect that water, disposed within the low permeability zone, vaporizes and effects formation of one or more flow paths through the low permeability zone;

5. The process as claimed in any one of claims 1 to 4;

wherein:

the mobilizing is effected by stimulation with a production-initiating fluid injected into the reservoir via an injection well, wherein the production-initiating fluid including steam; and

the conduction is effected by gravity drainage to a production well;

such that the mobilizing and the conducting is effected by a SAGD process.

6. The process as claimed in claim 5;

wherein the low permeability zone is disposed between a horizontal section of the injection well and a horizontal section of the production well.

7. The process as claimed in claim 6;

wherein at least a continuous portion of the permeability zone is disposed between a horizontal section of the injection well and a horizontal section of the production well, and the continuous portion has an axis, and the axis has a length of at least 50 metres.

8. The process as claimed in claim 7;

wherein:

the injection and production wells define a first well pair; and

the at least a continuous portion of the low permeability zone is also extending across at least ⅓ of a spacing distance between the first well pair and a second well pair.

9. The process as claimed in claim 7;

wherein:

the injection and production wells define a first well pair; and

the at least a continuous portion of the low permeability zone is disposed between the horizontal sections of the first and second wells and is also extending from between the horizontal sections and towards a second well pair by a distance of at least 25 metres.

9. The process as claimed in claim 6;

wherein:

the injection and production wells define a first well pair; and

at least a continuous laterally-extending portion of the low permeability zone is disposed between the horizontal sections of the first and second wells and is also extending across at least ⅓ of a spacing distance between the first well pair and a second well pair.

10. The process as claimed in claim 6;

wherein:

the injection and production wells define a first well pair; and

at least a continuous laterally-extending portion of the low permeability zone is disposed between the horizontal sections of the first and second wells and is also extending from between the horizontal sections and towards a second well pair by a distance of at least 50 metres.

11. The process as claimed in claim 5;

wherein the low permeability zone is disposed above a horizontal section of the injection well.

12. The process as claimed in claim 11;

wherein the low permeability zone is disposed above the horizontal section of the injection well by a minimum distance of less than 15 metres.

13. The process as claimed in claim 11

wherein the low permeability zone is disposed above the horizontal section of the well and at a height of less than 35 metres above the bottom of the reservoir.

14. The process as claimed in any one of claims 1 to 13

wherein the low permeability zone has an absolute permeability of less than 1000 millidarcies.

15. The process as claimed in any one of claims 1 to 13;

wherein the low permeability zone has an absolute permeability of less than 10 millidarcies.

16. The process as claimed in any one of claims 1 to 15;

wherein the low permeability zone has a dimension of at least 10 metres.

17. The process as claimed in any one of claims 1 to 15;

wherein at least a continuous portion of the low permeability zone is disposed within a horizontal plane within the reservoir, wherein the horizontal plane-disposed continuous portion of the low permeability zone is characterized by an area of at least 100 square metres.

18. A process for producing hydrocarbon material from a reservoir, comprising:

pressurizing the cooled portion of the low permeability zone with effect that one or more flow paths are formed through the low permeability zone; and

receiving hydrocarbon material, that is conducted through the one or more of the flow paths, within a production well; and

producing the received hydrocarbon material.

19. The process as claimed in claim 18;

wherein the pressurizing is effected in response to hydraulic fracturing.