CA2988164C - Methods for establishing fluid communication between a sagd well pair - Google Patents
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- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
There is provided a method of establishing fluid communication in an interwell region between an injection well and a production well forming the well pair includes electrically heating the interwell region between injection well and production well.
Description
METHODS FOR ESTABLISHING FLUID COMMUNICATION
BETWEEN A SAGD WELL PAIR
This application is a divisional application of Canadian Patent Application No. 2,847,141, filed on March 21, 2014.
FIELD
[00011 The present disclosure relates to methods for effecting fluid communication between two wells in a hydrocarbon containing reservoir.
BACKGROUND
BETWEEN A SAGD WELL PAIR
This application is a divisional application of Canadian Patent Application No. 2,847,141, filed on March 21, 2014.
FIELD
[00011 The present disclosure relates to methods for effecting fluid communication between two wells in a hydrocarbon containing reservoir.
BACKGROUND
[0002] Steam Assisted Gravity Drainage (SAGD) uses a pair of wells to produce a hydrocarbon from a hydrocarbon containing reservoir. Typically the well pair includes two horizontal wells vertically spaced from one another, with the upper well used to inject steam into the reservoir and the lower well to produce the hydrocarbon. The steam operates to generate a steam chamber in the reservoir, and thermal heat from the steam operates to lower the viscosity of the hydrocarbon, allowing for gravity drainage, and thereby production from the production well.
Typically, before production commences from the production well, a "start-up"
period is required to warm the interwell region of the reservoir between the two wells. Heating to a mobility threshold enables displacement of the viscous hydrocarbon from the interwell region to result in effective fluid communication between the injection well and the production well.
Typically, before production commences from the production well, a "start-up"
period is required to warm the interwell region of the reservoir between the two wells. Heating to a mobility threshold enables displacement of the viscous hydrocarbon from the interwell region to result in effective fluid communication between the injection well and the production well.
[0003] Steam circulation during the start-up period to pre-heat SAGD well pairs is a routine yet challenging process. Steam circulation may be hydraulically difficult to start or sustain and the circulation effort may be adversely affected by reservoir heterogeneity near the wellbore or between the injector and producer. Non-uniform heating of the wellbore, and interwell region of the hydrocarbon containing reservoir during steam circulation results in less than optimal SAGD
production from the reservoir and higher SOR (steam to oil ratio). Also, steam circulation may not always be suitable for SAGD start-up where the reservoir is relatively shallow, confined by weak or non-existent cap-rock.
production from the reservoir and higher SOR (steam to oil ratio). Also, steam circulation may not always be suitable for SAGD start-up where the reservoir is relatively shallow, confined by weak or non-existent cap-rock.
[0004] Another challenge with steam circulation as a start-up technique results from the delay between drilling the well pairs and the availability of surface facilities to provide steam to the wells.
Generally, after SAGD well pairs have been drilled and completed, surface facilities are constructed to enable utilization of steam from a steam generation facility within the SAGD
well pair. There can be a significant time elapse after the well pair is drilled until these facilities to provide steam are constructed. Elapsed time varies but delays can be up to two years.
SUMMARY
100051 In one aspect, a method of establishing fluid communication in an interwell region between an injection well and a production well forming the well pair includes electrically heating the interwell region between injection well and production well.
[0006] In some implementations, the electrical heating of the interwell region is effected by an electrical heating system disposed within the injection well and/or the production -well.
[0007] In another aspect, a method of producing bitumen from an oil sands reservoir includes, during a start-up phase, electrically heating an interwell region of the oil sands reservoir disposed between an injection well and a production well, for establishing a fluid communication between between the injection well and the production well.
After establishing the fluid communication, a production phase is commenced that includes injecting steam from the injection well into the oil sands reservoir for effecting mobilization of bitumen within the oil sands reservoir. The mobilized bitumen is conducted through the interwell region to the production well and recovered to surface through the production well.
[0008] In some implementations, the method further includes, after establishing fluid communication in the interwell region, supplying steam from a steam generator, where the steam being injected is the steam supplied from the steam generator. Electrically heating the interwell region can be completed prior to, or substantially completed prior to, commissioning of steam facilities for effecting the supplying of steam from the steam generator to the injection well.
[0009] The electrical heating of the interwell region can be effected while steam facilities, for effecting the supplying of stearn from the steam generator to the injection well, are being constructed.
[00101 The electrical heating of the interwell region can be effected by an electrical heating system disposed within the injection well and/or the production well.
[00111 The interwell region can be defined within a shallow hydrocarbon reservoir.
[0012] The interwell region is the region of the reservoir that is between the injection well and the production well, which in a typical SAGD operation is approximately 5 metres in depth.
In some reservoirs, the bitumen saturation is greater than 85% and the porosity is greater than 35%, although reservoirs vary in these characteristics and the bitumen saturation and/or porosity could be lower in some instances.
[00131 In another aspect, a method of establishing fluid communication between a well pair within an oil sands reservoir includes electrically heating an interwell region of the oil sands reservoir disposed between an injection well and a production well, to at least contribute to establishing fluid communication in the interwell region. The electrical heating includes:
electrically heating a first portion of the interwell region at a first predetermined heating rate; and electrically heating a second portion of the interwell region at a different second predetermined heating rate while the first portion is being heated at the first predetermined rate.
[00111] In some implementations, the first predetermined heating rate and the second predetermined heating rate are selected to effect a substantially uniform heating of the interwell region.
[00151 In some implementations, the electrical heating of an interwell region is effected by an electrical heating system disposed within at least one of the injection well and the production well.
[0016] In another aspect, a method of establishing fluid communication between a well pair comprising an injection well and a production well within an oil sands reservoir includes heating an interwell region disposed between the injection well and the production well, establishing fluid communication between the two wells. The heating includes heating the interwell region with heat generated by steam injected into at least one well in the well pair and simultaneously with heat generated by an electric heating system. Heat generated by the electric heating system effects both heating of the interwell region and heating of the injected steam.
[0017] In some implementations, the steam injected into the at least one well is injected into the well and circulated to surface.
[0018] In some implementations, the steam injected into the at least one well is injected into the reservoir, i.e., bull heading.
[0019] In some implementations, the steam carries a gaseous chemical additive material and condensation of the chemical additive material is mitigated by the electric heating of the steam.
[0020] In some implementations, the electric heating system is disposed within at least one of the wells in the well pair.
[0021] In another aspect, a method method of producing bitumen from an oil sands reservoir includes, after a fluid communicating interwell region has been established between and injection well and a production well forming a well pair, injecting steam into the oil sands reservoir via the injection well for effecting mobilization of bitumen within the oil sands reservoir. The mobilized bitumen is conducted through the established fluid communicating interwell region to the production well. While the steam is being injected, the injected steam is heated with an electrical heating system situated in the injection well. The mobilized bitumen is recovered to surface through the production well.
(0022) In some implementations, the injected steam carries a gaseous chemical additive material, and the electrical heating of the injected steam is such that condensation of the chemical additive material is mitigated.
100231 In some implementations, prior to the injecting steam for effecting mobilization, the interwell region is electrically heated with the electrical heating system, which at least contributes to establishing a fluid communicating interwell region for effecting fluid communication between the injection well and the production well.
[0024] In another aspect, a method of producing bitumen from an oil sands reservoir includes electrically heating an interwell region, of the oil sands reservoir, disposed between an injection well and a production well established within the oil sands reservoir, with an electrical heating system. After the fluid communicating interwell region has been effected, steam assisted gravity drainage (SAGD) is conducted to produce the bitumen, wherein the SAGD
includes:
injecting steam into the oil sands reservoir via the injection well for effecting mobilization of bitumen disposed within the oil sands reservoir such that the mobilized bitumen is conducted through the established fluid communicating interwell region to the production well; and recovering the mobilized bitumen through the production well. While SAGD is being conducted, a problem is detected requiring well intervention. In response to the detecting of the problem requiring well intervention, SAGD is suspended and the wellbore fluids disposed within one or both of the wells are electrically heated with the electrical heating system. The wellbore fluids are vaporized and are conducted through the respective well to the wellhead.
[0025] In some implementations, the electrical heating system is disposed in the injection well and/or the production well.
[0026] In another aspect, a method of producing bitumen from an oil sands reservoir includes establishing fluid communication between an injection well and a production well for use as a steam assisted gravity drainage (SAGD) well pair by exclusively using electrical heat applied in situ. The method can further include, only after establishing the fluid communication, commencing injcction of steam into the oil sands reservoir via the injection well and producing production fluid from the oil sands reservoir via the production well, wherein the production fluid includes bitumen.
BRIEF DESCRIPTION OF DRAWINGS
[0027] The preferred embodiments will now be described with the following accompanying drawings, in which;
[0028] Figure 1 is a schematic illustration of a well pair in an oil sands reservoir, where fluid communication between the pair is to be established by embodiments of methods described herein;
[0029] Figure 2 is a schematic illustration of a Mineral Insulated ("MI") heater cable;
[0030] Figure 3 is a schematic illustration of a system for deploying an electrical heating system within a wellbore for enabling practising of methods described herein;
[0031] Figure 4 is a cross-sectional view of a coiled tube, from one end, including three MI
heater cables illustrated in Figure 2; and 100321 Figure 5 is a cross-sectional side view of a coiled tube, including three MI heater cables illustrated in Figure 2.
DETAILED DESCRIPTION
100331 There is provided a method for effecting fluid communication between a pair of wells within a hydrocarbon containing reservoir during the start-up phase of a SAGD operation.
The wells are separated by an interwell region of the reservoir. For illustrative purposes below, an oil sands reservoir from which bitumen is being produced is described.
However, it should be understood, that the techniques described could be used in other types of hydrocarbon containing reservoirs where SAGD is employed.
[0034] Referring to Figure 1, in a typical SAGD well pair, the wells are spaced vertically from one another, such as wells 10 and 20, and the vertically higher well, i.e., well 10, is used for steam injection during a production phase of the SAGD operation, and the lower well, i.e., well 20, is used for production during the production phase. In a conventional start-up phase, steam is circulated through both wells 10 and 20, for the purpose of warming the interwell region 15 primarily by conduction. As the interwell region 15 warms, the viscosity of the bitumen contained in that region is reduced, mobilizing the bitumen which can then be produced from the production well 20.
[0035] In the implementation shown, a cased-hole completion includes casing 40 run down the wellbore 10 and 20 through the production zone. The casing may be cemented to the subterranean oil sands reservoir for effecting zonal isolation. A liner may be hung from the last section of casing. The liner can be made from the same material as the casing string, but, unlike the casing string, the liner does not extend back to the wellhead. The liner is slotted or perforated to effect communication with the reservoir.
[0036] Fluid conducting tubing 50 or multiple tubing strings can be installed inside the last casing string of the injection well, well 10. The tubing(s) 50 is provided to conduct steam and steam condensate from the wellhead 60 to the liner and sequentially to the reservoir.
100371 Fluid conducting tubing 50 or multiple tubing strings can be installed inside the last casing string of the production well, well 20.
[0038] In the illustrated embodiment, a perforated liner is provided in each of the wells 10, 20, for enabling fluid communication between the tubing 50 and the reservoir 30. During the production phase of the SAGD operation, steam injected through the well 10 (typically referred to as the "injection well") is conducted within the tubing or casing annulus or both, through the liner, and into the reservoir 30. The injected steam mobilizes the bitumen within the oil sands reservoir 30. The mobilized bitumen and steam condensate drains through the interwell region 15 by gravity to the well 20 (typically referred to as the "production well"), collects in the liner and is surfaced through tubing 50 or by artificial lift to the surface 5.
[0039] Prior to the production phase, the fluid communication between the wells 10, 20 is established through the interwell region 15 during a start-up phase. Unlike the conventional start-up technique, which relies solely on steam to achieve fluid communication, techniques and systems are described where fluid communication between the injection well 10 and the production well 20 is enabled by electrical heating of the interwell region 15. An in situ electrical heat source raises temperature uniformly, or substantially uniformly, along the wellbore installation and heats the surrounding reservoir by conduction.
Electrical heating of the interwell region 15 is more uniform, relative to steam circulation. As well, in comparison to using steam circulation for start-up, the heat generated within the interwell region by electrical sources can be easier to control. This is because heating of the interwell region responds faster to modulation of electrical sources than it does for modulation of steam sources.
[0040] A
typical wellbore includes cement between the casing and the reservoir material.
Cement integrity can be compromised by pronounced thermal cycling and/or abrupt transitions of heating rates in situ. Electrical heat provides a controllable heat source that can avoid or reduce these events, and cement integrity is more likely to be maintained for a longer period of time, than in a well pair relying solely on steam circulation for start-up.
[0041] In a typical SAGD operation, there are multiple well pairs drilled into the reservoir.
After the well pairs are drilled and completed, surface facilities must be built before the SAGD
operation can commence. The surface facilities may include steam generating units or steam distribution pipelines and manifolds. Until the steam generating units are complete, there is no source of steam and the start-up phase cannot commence. Advantageously, when using electrical heat as the heat source for the start-up phase, the start-up phase can commence at any time after the well pairs are completed and prior to completion of the surface facilities.
Considering the time that can elapse between the well pairs being drilled and the surface facilities being completed can be two or more years, a significant time advantage can be realized by employed electrical heat.
[0042] In some implementations, electrical heat is the sole source of heat during the start-up phase, and fluid communication in the interwell region 15 can be enabled without any circulation of steam in the injection well 10 or the production well 20. In other implementations, electrical heat is employed as the initial source of heat during the start-up phase, and particularly while a steam source is unavailable. Once surface facilities including a steam source are complete, a final stage of the start-up phase can include both electrical heat and steam injection to displace highly viscous hydrocarbons from interwell region 15. In other implementations electrical heat in the production well 20 and steam circulation in the injection well 10 could be applied for heating interwell region 15 . In other implementations, electrical heat is employed as the initial source of heat, and once surface facilities including a steam source unit are complete, the final stage of the start-up phase is by steam circulation only, e.g., in one or both of the wells 10, 20, In any of these implementations, by employing electrical heat as a start-up phase heat source during the time period when steam was unavailable, start-up is achieved sooner than would have been the case if relying on steam only. Accordingly, the SAGD
operation can move into the production phase sooner. By accelerating start-up of SAGD, pad economics are improved by virtue of the earlier production of bitumen. Additionally, start-up can be achieved using significantly less steam, resulting in an improved SOR.
[00431 In some embodiments, the electrical heating is by an electrical heating system that is disposed in the injection well and/or the production well. In addition to an electrical heater or an electrical heating system, heating can be by one or more other artificial sources of heat. That is, in addition to electrical heating of the interwell region 15, one or more other artificial sources of heat can supply heat to the interwell region 15, such that the heating in the interwell region 15 is caused by heat supplied by the electrical heating as well as heating by the other artificial sources of heat. Where, in addition to an electrical heater or an electrical heating system, there is at least one or more other artificial sources of heat that is supplying the heat to the interwell region 15, each one of the multiple artificial sources of heat may be supplying the heat to the interwell region 15 independently of one another or in co-ordination or controlled co-operation with one or more of the other heat sources. Also, each one of the multiple sources of heat may be supplying the heat to the interwell region 15 simultaneously with one or more of the other heat sources, asynchronously relative to one or more of the other heat sources, or any combination thereof. An example of another artificial source of heat is steam.
In this respect, heating of the interwell region 15 can also be caused by steam injection through one or both of the wells 10, 20. In some implementations, the steam injection is effected by steam circulation within the well. In such case, the steam is injected through a fluid passage provided within the well (such as, for example, the fluid conducting tubing 50) to the toe of the well, becomes disposed in thermal communication with the reservoir 30 and effects heating of the interwell region 15, and is then returned to the surface 5 through another fluid passage defined within the well (such as, for example, the annulus between the tubing 50 and the casing 40). In other implementations, the steam injection is effected by bullheading. In such case, the steam is injected through a fluid passage provided within the well (such as, for example, the fluid conducting tubing and/or the annulus between the tubing 50 and the casing 40) and supplied to the reservoir 30.
100441 In some implementations, the interwell region is defined within a shallow hydrocarbon reservoir that includes bitumen. A shallow hydrocarbon reservoir is a hydrocarbon reservoir that is disposed less than 140 metres from the surface. For shallow hydrocarbon reservoirs, using conventional steam circulation to establish fluid communication between the wells 10, 20 can create environmental risks, as the steam pressure may effect fractures within the oil sands reservoir 30, and thereby effect conduction of the bitumen and/or steam to undesirable locations within the oil sands reservoir 30, or to surface. In this respect, by using electrical system to heat the interwell region 15 and enable displacement of immobile bitumen between the wells 10, 20, the risk of damaging the oil sands reservoir 30, or causing undesirable surface releases of bitumen or steam, is avoided.
100451 In another aspect, the interwell region 15 is defined within a poor geology reservoir. A poor geology reservoir is a reservoir with a bitumen saturation of less than 85% and a porosity of less than 30%. Bitumen saturation of a reservoir is the mass concentration of bitumen within the reservoir. Porosity of a reservoir is the volumetric fraction of empty space within the reservoir, expressed as a percentage. It can be desirable to use electrical heating to at least partially contribute to the establishment of fluid communication through such an interwell region 15 during the start-up phase, rather than solely relying on steam to establish the fluid communication. This is because it is relatively difficult for steam to be conducted through a poor geology reservoir. Comparatively, the establishment of fluid communication through the interwell region 15 in a poor geology reservoir is faster when electrical heating is used to heat such interwell region 15.
[0046] In some implementations, different portions of the interwell region 15 are independently electrically heated so as to differentially mobilize the fluid within interwell region 15. Electrically heating the interwell region 15 can include electrically heating a first portion of the interwell region 15 at a first predetermined heating rate and, while the first portion is being electrically heated at the first predetermined heating rate, electrically heating a second portion of the interwell region at a different second predetermined heating rate. It can be desirable to independently control the rate of heating of one or more portions of the interwell region 15 from the rate of heating of one or more other portions of the interwell region 15 if some portions have different thermal characteristics (e.g. thermal conductivity and heat capacity) than other portions and therefore, require different rates of heating to achieve uniform (or substantially uniform) temperature conditions.
[0047] In some implementations, heating of the interwell region 15 is by at least both: (i) electrical heating and (ii) steam injection through one or both of the injector and production wells. In such implementations, steam is injected through at least one of the wells 10, 20 while electrically heating the interwell region 15 with an electrical heating system, disposed within a respective one or more of the wells 10, 20 through which the steam is being injected. In this respect, the injected steam is also heated by the electrical heating system.
The heating of the steam can improve or maintain steam quality. In some implementations, the steam injection is effected during steam circulation. In other implementations, the steam injection is effected while bullheading.
[0048] In some embodiments, for example, during start-up, the injected steam carries a gaseous chemical additive material for supply to the interwell region 15. The gaseous chemical additive material is configured for promoting establishment of the fluid communicating interwell region 15. Suitable chemical additives include a surface tension adjusting agent, such as a detergent. A surface tension adjusting agent would be configured for affecting the surface tension between the bitumen and the rock such that separation of the bitumen from the rock is facilitated. Suitable chemical additives include cationic surfactants, such as alkyltrimethylammonium bromide and alkyldimethylammonium bromide. Other suitable chemical additives include alcohol propoxylate sulfate and alkyl sulfonate surfactants. Further suitable chemical additives include hydrocarbon materials, such as butane, propane or diesel.
Such hydrocarbon materials arc provided for enhancing the mobility of the bitumen within the reservoir. In this respect, in addition to the injected steam being heated by the electrical heating system, where the injected steam is carrying the gaseous chemical additive material, the gaseous chemical additive material is also heated by the electrical heating system, such that condensation of the gaseous chemical additive material is prevented or at least mitigated, and that the chemical additive material remains in the gaseous phase so its supply to the reservoir is enabled.
[0049] In another aspect, an electrical heating system disposed within at least one of the injector and production wells 10, 20, at least partially contributes to heating of the interwell region 15. After the interwell region 15 has been heated to effect, SAGD is conducted, and SAGD includes injecting steam from the injection well 10 into the oil sands reservoir 30 for mobilizing bitumen within the oil sands reservoir 30 such that the mobilized bitumen is conducted through the interwell region 15 to the production well 20, and recovering the mobilized bitumen through the production well 20. While SAGD is being conducted, a problem may be detected requiring well intervention. Well intervention may be required, for example, to replace downhole equipment or instrumentation, such as submersible pumps, long tubing, plugged components, or optical fibre. In response to the detecting of the problem, SAGD is suspended so as to permit well intervention. After the suspending of SAGD, wellbore fluids within one or both of the wells 10, 20 may be conducted to the surface by electrically heating the wellbore fluids with the electrical heating system, such that the wellbore fluids are vaporized and are conducted through the respective well 10 or 20 to the surface 5. In some embodiments, for example, the electrical heating system may have also been used to heat the steam being supplied to the injection well 10 during SAGD. By enabling conduction of the wellbore fluids in this manner, use of pumping units or other lifting mechanism can be avoided. As well, removal of the wellbore fluids using electrical heaters is more effective than by using pumping units or other lift mechanisms, and thereby mitigates the risk of possible undesirable chemical reactions between residual wellbore fluids and fluids being introduced to the wellbore during well intervention.
[0050] In some embodiments, for example, the electrical heating is by an electrical heating system. In some of these embodiments, for example, an electrical heating system is disposed in one or both of the wells 10. In some of these embodiments, for example, the electrical heating system includes a heater cable. The heater cable includes a wire surrounded by insulation (e.g.
mineral insulation) and disposed within a metallic sheath. The wire is electrically coupled to a power source and a controller and, in this respect, is configured to effect heating of the interwell region 15 by conduction. An example of a suitable heater cable is a mineral-insulated ("MI") heater cable 70. Referring to Figure 2, a MI heater cable 70 includes an electrically conducting core 72, surrounded by a metallic sheath 74 (for example, a 304L sheath) with a mineral insulation layer 76 (for example, magnesium oxide) disposed between the metallic sheath 74 and the core 72. In some embodiments, for example, the heater cable 70 can include relatively hotter and relatively colder sections. This is enabled by using different materials in different sections of the cable. In this respect, by having relatively hotter and relatively colder section, different heating rates can be provided for different portions of the interwell region 15 in some embodiments.
[0051] Referring to Figure 3, in some of these embodiments, for example, the heater cable is deployed within a coiled tube 60. Referring to Figures 4 and 5, in some embodiments, for example, multiple cables 70 are deployed within the coiled tube 60. In some embodiments, for example, the cables 70 are mounted to a support rod 80 for maintaining positioning the cables 70. In the illustrated embodiment, for example, the heater cable is a three (3) phase heater consisting of three (3) single conductor MI heater cables 70 disposed in a coiled tube 60 that is deployed from a reel 90 disposed on the surface 5. The MI heater cables 70 are assembled into complete heater units by installing a wye splice 100 at the bottom of the cables 70 for forming a dielectrically insulated connection.
[0052] Other forms of electrical heating devices can be used, and are not limited to those discussed herein.
[0053]
Reference throughout the specification to "one embodiment," "an embodiment,"
"some embodiments," "one aspect," "an aspect," or "some aspects" means that a particular feature, structure, method, or characteristic described in connection with the embodiment or aspect is included in at least one embodiment of the present invention. In this respect, the appearance of the phrases "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, methods, or characteristics may be combined in any suitable manner in one or more embodiments.
[0054] Each numerical value should be read once as modified by the term "about" (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the sumrnary arid this detailed description, it should be understood that a concentration range listed or described as being useful, suitable, or the like, is intended that any and every concentration within the range, including the end points, is to be considered as having been stated. For example, "a range of from 1 to 10" is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific data points, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors have disclosed and enabled the entire range and all points within the range.
[0055] 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.
Generally, after SAGD well pairs have been drilled and completed, surface facilities are constructed to enable utilization of steam from a steam generation facility within the SAGD
well pair. There can be a significant time elapse after the well pair is drilled until these facilities to provide steam are constructed. Elapsed time varies but delays can be up to two years.
SUMMARY
100051 In one aspect, a method of establishing fluid communication in an interwell region between an injection well and a production well forming the well pair includes electrically heating the interwell region between injection well and production well.
[0006] In some implementations, the electrical heating of the interwell region is effected by an electrical heating system disposed within the injection well and/or the production -well.
[0007] In another aspect, a method of producing bitumen from an oil sands reservoir includes, during a start-up phase, electrically heating an interwell region of the oil sands reservoir disposed between an injection well and a production well, for establishing a fluid communication between between the injection well and the production well.
After establishing the fluid communication, a production phase is commenced that includes injecting steam from the injection well into the oil sands reservoir for effecting mobilization of bitumen within the oil sands reservoir. The mobilized bitumen is conducted through the interwell region to the production well and recovered to surface through the production well.
[0008] In some implementations, the method further includes, after establishing fluid communication in the interwell region, supplying steam from a steam generator, where the steam being injected is the steam supplied from the steam generator. Electrically heating the interwell region can be completed prior to, or substantially completed prior to, commissioning of steam facilities for effecting the supplying of steam from the steam generator to the injection well.
[0009] The electrical heating of the interwell region can be effected while steam facilities, for effecting the supplying of stearn from the steam generator to the injection well, are being constructed.
[00101 The electrical heating of the interwell region can be effected by an electrical heating system disposed within the injection well and/or the production well.
[00111 The interwell region can be defined within a shallow hydrocarbon reservoir.
[0012] The interwell region is the region of the reservoir that is between the injection well and the production well, which in a typical SAGD operation is approximately 5 metres in depth.
In some reservoirs, the bitumen saturation is greater than 85% and the porosity is greater than 35%, although reservoirs vary in these characteristics and the bitumen saturation and/or porosity could be lower in some instances.
[00131 In another aspect, a method of establishing fluid communication between a well pair within an oil sands reservoir includes electrically heating an interwell region of the oil sands reservoir disposed between an injection well and a production well, to at least contribute to establishing fluid communication in the interwell region. The electrical heating includes:
electrically heating a first portion of the interwell region at a first predetermined heating rate; and electrically heating a second portion of the interwell region at a different second predetermined heating rate while the first portion is being heated at the first predetermined rate.
[00111] In some implementations, the first predetermined heating rate and the second predetermined heating rate are selected to effect a substantially uniform heating of the interwell region.
[00151 In some implementations, the electrical heating of an interwell region is effected by an electrical heating system disposed within at least one of the injection well and the production well.
[0016] In another aspect, a method of establishing fluid communication between a well pair comprising an injection well and a production well within an oil sands reservoir includes heating an interwell region disposed between the injection well and the production well, establishing fluid communication between the two wells. The heating includes heating the interwell region with heat generated by steam injected into at least one well in the well pair and simultaneously with heat generated by an electric heating system. Heat generated by the electric heating system effects both heating of the interwell region and heating of the injected steam.
[0017] In some implementations, the steam injected into the at least one well is injected into the well and circulated to surface.
[0018] In some implementations, the steam injected into the at least one well is injected into the reservoir, i.e., bull heading.
[0019] In some implementations, the steam carries a gaseous chemical additive material and condensation of the chemical additive material is mitigated by the electric heating of the steam.
[0020] In some implementations, the electric heating system is disposed within at least one of the wells in the well pair.
[0021] In another aspect, a method method of producing bitumen from an oil sands reservoir includes, after a fluid communicating interwell region has been established between and injection well and a production well forming a well pair, injecting steam into the oil sands reservoir via the injection well for effecting mobilization of bitumen within the oil sands reservoir. The mobilized bitumen is conducted through the established fluid communicating interwell region to the production well. While the steam is being injected, the injected steam is heated with an electrical heating system situated in the injection well. The mobilized bitumen is recovered to surface through the production well.
(0022) In some implementations, the injected steam carries a gaseous chemical additive material, and the electrical heating of the injected steam is such that condensation of the chemical additive material is mitigated.
100231 In some implementations, prior to the injecting steam for effecting mobilization, the interwell region is electrically heated with the electrical heating system, which at least contributes to establishing a fluid communicating interwell region for effecting fluid communication between the injection well and the production well.
[0024] In another aspect, a method of producing bitumen from an oil sands reservoir includes electrically heating an interwell region, of the oil sands reservoir, disposed between an injection well and a production well established within the oil sands reservoir, with an electrical heating system. After the fluid communicating interwell region has been effected, steam assisted gravity drainage (SAGD) is conducted to produce the bitumen, wherein the SAGD
includes:
injecting steam into the oil sands reservoir via the injection well for effecting mobilization of bitumen disposed within the oil sands reservoir such that the mobilized bitumen is conducted through the established fluid communicating interwell region to the production well; and recovering the mobilized bitumen through the production well. While SAGD is being conducted, a problem is detected requiring well intervention. In response to the detecting of the problem requiring well intervention, SAGD is suspended and the wellbore fluids disposed within one or both of the wells are electrically heated with the electrical heating system. The wellbore fluids are vaporized and are conducted through the respective well to the wellhead.
[0025] In some implementations, the electrical heating system is disposed in the injection well and/or the production well.
[0026] In another aspect, a method of producing bitumen from an oil sands reservoir includes establishing fluid communication between an injection well and a production well for use as a steam assisted gravity drainage (SAGD) well pair by exclusively using electrical heat applied in situ. The method can further include, only after establishing the fluid communication, commencing injcction of steam into the oil sands reservoir via the injection well and producing production fluid from the oil sands reservoir via the production well, wherein the production fluid includes bitumen.
BRIEF DESCRIPTION OF DRAWINGS
[0027] The preferred embodiments will now be described with the following accompanying drawings, in which;
[0028] Figure 1 is a schematic illustration of a well pair in an oil sands reservoir, where fluid communication between the pair is to be established by embodiments of methods described herein;
[0029] Figure 2 is a schematic illustration of a Mineral Insulated ("MI") heater cable;
[0030] Figure 3 is a schematic illustration of a system for deploying an electrical heating system within a wellbore for enabling practising of methods described herein;
[0031] Figure 4 is a cross-sectional view of a coiled tube, from one end, including three MI
heater cables illustrated in Figure 2; and 100321 Figure 5 is a cross-sectional side view of a coiled tube, including three MI heater cables illustrated in Figure 2.
DETAILED DESCRIPTION
100331 There is provided a method for effecting fluid communication between a pair of wells within a hydrocarbon containing reservoir during the start-up phase of a SAGD operation.
The wells are separated by an interwell region of the reservoir. For illustrative purposes below, an oil sands reservoir from which bitumen is being produced is described.
However, it should be understood, that the techniques described could be used in other types of hydrocarbon containing reservoirs where SAGD is employed.
[0034] Referring to Figure 1, in a typical SAGD well pair, the wells are spaced vertically from one another, such as wells 10 and 20, and the vertically higher well, i.e., well 10, is used for steam injection during a production phase of the SAGD operation, and the lower well, i.e., well 20, is used for production during the production phase. In a conventional start-up phase, steam is circulated through both wells 10 and 20, for the purpose of warming the interwell region 15 primarily by conduction. As the interwell region 15 warms, the viscosity of the bitumen contained in that region is reduced, mobilizing the bitumen which can then be produced from the production well 20.
[0035] In the implementation shown, a cased-hole completion includes casing 40 run down the wellbore 10 and 20 through the production zone. The casing may be cemented to the subterranean oil sands reservoir for effecting zonal isolation. A liner may be hung from the last section of casing. The liner can be made from the same material as the casing string, but, unlike the casing string, the liner does not extend back to the wellhead. The liner is slotted or perforated to effect communication with the reservoir.
[0036] Fluid conducting tubing 50 or multiple tubing strings can be installed inside the last casing string of the injection well, well 10. The tubing(s) 50 is provided to conduct steam and steam condensate from the wellhead 60 to the liner and sequentially to the reservoir.
100371 Fluid conducting tubing 50 or multiple tubing strings can be installed inside the last casing string of the production well, well 20.
[0038] In the illustrated embodiment, a perforated liner is provided in each of the wells 10, 20, for enabling fluid communication between the tubing 50 and the reservoir 30. During the production phase of the SAGD operation, steam injected through the well 10 (typically referred to as the "injection well") is conducted within the tubing or casing annulus or both, through the liner, and into the reservoir 30. The injected steam mobilizes the bitumen within the oil sands reservoir 30. The mobilized bitumen and steam condensate drains through the interwell region 15 by gravity to the well 20 (typically referred to as the "production well"), collects in the liner and is surfaced through tubing 50 or by artificial lift to the surface 5.
[0039] Prior to the production phase, the fluid communication between the wells 10, 20 is established through the interwell region 15 during a start-up phase. Unlike the conventional start-up technique, which relies solely on steam to achieve fluid communication, techniques and systems are described where fluid communication between the injection well 10 and the production well 20 is enabled by electrical heating of the interwell region 15. An in situ electrical heat source raises temperature uniformly, or substantially uniformly, along the wellbore installation and heats the surrounding reservoir by conduction.
Electrical heating of the interwell region 15 is more uniform, relative to steam circulation. As well, in comparison to using steam circulation for start-up, the heat generated within the interwell region by electrical sources can be easier to control. This is because heating of the interwell region responds faster to modulation of electrical sources than it does for modulation of steam sources.
[0040] A
typical wellbore includes cement between the casing and the reservoir material.
Cement integrity can be compromised by pronounced thermal cycling and/or abrupt transitions of heating rates in situ. Electrical heat provides a controllable heat source that can avoid or reduce these events, and cement integrity is more likely to be maintained for a longer period of time, than in a well pair relying solely on steam circulation for start-up.
[0041] In a typical SAGD operation, there are multiple well pairs drilled into the reservoir.
After the well pairs are drilled and completed, surface facilities must be built before the SAGD
operation can commence. The surface facilities may include steam generating units or steam distribution pipelines and manifolds. Until the steam generating units are complete, there is no source of steam and the start-up phase cannot commence. Advantageously, when using electrical heat as the heat source for the start-up phase, the start-up phase can commence at any time after the well pairs are completed and prior to completion of the surface facilities.
Considering the time that can elapse between the well pairs being drilled and the surface facilities being completed can be two or more years, a significant time advantage can be realized by employed electrical heat.
[0042] In some implementations, electrical heat is the sole source of heat during the start-up phase, and fluid communication in the interwell region 15 can be enabled without any circulation of steam in the injection well 10 or the production well 20. In other implementations, electrical heat is employed as the initial source of heat during the start-up phase, and particularly while a steam source is unavailable. Once surface facilities including a steam source are complete, a final stage of the start-up phase can include both electrical heat and steam injection to displace highly viscous hydrocarbons from interwell region 15. In other implementations electrical heat in the production well 20 and steam circulation in the injection well 10 could be applied for heating interwell region 15 . In other implementations, electrical heat is employed as the initial source of heat, and once surface facilities including a steam source unit are complete, the final stage of the start-up phase is by steam circulation only, e.g., in one or both of the wells 10, 20, In any of these implementations, by employing electrical heat as a start-up phase heat source during the time period when steam was unavailable, start-up is achieved sooner than would have been the case if relying on steam only. Accordingly, the SAGD
operation can move into the production phase sooner. By accelerating start-up of SAGD, pad economics are improved by virtue of the earlier production of bitumen. Additionally, start-up can be achieved using significantly less steam, resulting in an improved SOR.
[00431 In some embodiments, the electrical heating is by an electrical heating system that is disposed in the injection well and/or the production well. In addition to an electrical heater or an electrical heating system, heating can be by one or more other artificial sources of heat. That is, in addition to electrical heating of the interwell region 15, one or more other artificial sources of heat can supply heat to the interwell region 15, such that the heating in the interwell region 15 is caused by heat supplied by the electrical heating as well as heating by the other artificial sources of heat. Where, in addition to an electrical heater or an electrical heating system, there is at least one or more other artificial sources of heat that is supplying the heat to the interwell region 15, each one of the multiple artificial sources of heat may be supplying the heat to the interwell region 15 independently of one another or in co-ordination or controlled co-operation with one or more of the other heat sources. Also, each one of the multiple sources of heat may be supplying the heat to the interwell region 15 simultaneously with one or more of the other heat sources, asynchronously relative to one or more of the other heat sources, or any combination thereof. An example of another artificial source of heat is steam.
In this respect, heating of the interwell region 15 can also be caused by steam injection through one or both of the wells 10, 20. In some implementations, the steam injection is effected by steam circulation within the well. In such case, the steam is injected through a fluid passage provided within the well (such as, for example, the fluid conducting tubing 50) to the toe of the well, becomes disposed in thermal communication with the reservoir 30 and effects heating of the interwell region 15, and is then returned to the surface 5 through another fluid passage defined within the well (such as, for example, the annulus between the tubing 50 and the casing 40). In other implementations, the steam injection is effected by bullheading. In such case, the steam is injected through a fluid passage provided within the well (such as, for example, the fluid conducting tubing and/or the annulus between the tubing 50 and the casing 40) and supplied to the reservoir 30.
100441 In some implementations, the interwell region is defined within a shallow hydrocarbon reservoir that includes bitumen. A shallow hydrocarbon reservoir is a hydrocarbon reservoir that is disposed less than 140 metres from the surface. For shallow hydrocarbon reservoirs, using conventional steam circulation to establish fluid communication between the wells 10, 20 can create environmental risks, as the steam pressure may effect fractures within the oil sands reservoir 30, and thereby effect conduction of the bitumen and/or steam to undesirable locations within the oil sands reservoir 30, or to surface. In this respect, by using electrical system to heat the interwell region 15 and enable displacement of immobile bitumen between the wells 10, 20, the risk of damaging the oil sands reservoir 30, or causing undesirable surface releases of bitumen or steam, is avoided.
100451 In another aspect, the interwell region 15 is defined within a poor geology reservoir. A poor geology reservoir is a reservoir with a bitumen saturation of less than 85% and a porosity of less than 30%. Bitumen saturation of a reservoir is the mass concentration of bitumen within the reservoir. Porosity of a reservoir is the volumetric fraction of empty space within the reservoir, expressed as a percentage. It can be desirable to use electrical heating to at least partially contribute to the establishment of fluid communication through such an interwell region 15 during the start-up phase, rather than solely relying on steam to establish the fluid communication. This is because it is relatively difficult for steam to be conducted through a poor geology reservoir. Comparatively, the establishment of fluid communication through the interwell region 15 in a poor geology reservoir is faster when electrical heating is used to heat such interwell region 15.
[0046] In some implementations, different portions of the interwell region 15 are independently electrically heated so as to differentially mobilize the fluid within interwell region 15. Electrically heating the interwell region 15 can include electrically heating a first portion of the interwell region 15 at a first predetermined heating rate and, while the first portion is being electrically heated at the first predetermined heating rate, electrically heating a second portion of the interwell region at a different second predetermined heating rate. It can be desirable to independently control the rate of heating of one or more portions of the interwell region 15 from the rate of heating of one or more other portions of the interwell region 15 if some portions have different thermal characteristics (e.g. thermal conductivity and heat capacity) than other portions and therefore, require different rates of heating to achieve uniform (or substantially uniform) temperature conditions.
[0047] In some implementations, heating of the interwell region 15 is by at least both: (i) electrical heating and (ii) steam injection through one or both of the injector and production wells. In such implementations, steam is injected through at least one of the wells 10, 20 while electrically heating the interwell region 15 with an electrical heating system, disposed within a respective one or more of the wells 10, 20 through which the steam is being injected. In this respect, the injected steam is also heated by the electrical heating system.
The heating of the steam can improve or maintain steam quality. In some implementations, the steam injection is effected during steam circulation. In other implementations, the steam injection is effected while bullheading.
[0048] In some embodiments, for example, during start-up, the injected steam carries a gaseous chemical additive material for supply to the interwell region 15. The gaseous chemical additive material is configured for promoting establishment of the fluid communicating interwell region 15. Suitable chemical additives include a surface tension adjusting agent, such as a detergent. A surface tension adjusting agent would be configured for affecting the surface tension between the bitumen and the rock such that separation of the bitumen from the rock is facilitated. Suitable chemical additives include cationic surfactants, such as alkyltrimethylammonium bromide and alkyldimethylammonium bromide. Other suitable chemical additives include alcohol propoxylate sulfate and alkyl sulfonate surfactants. Further suitable chemical additives include hydrocarbon materials, such as butane, propane or diesel.
Such hydrocarbon materials arc provided for enhancing the mobility of the bitumen within the reservoir. In this respect, in addition to the injected steam being heated by the electrical heating system, where the injected steam is carrying the gaseous chemical additive material, the gaseous chemical additive material is also heated by the electrical heating system, such that condensation of the gaseous chemical additive material is prevented or at least mitigated, and that the chemical additive material remains in the gaseous phase so its supply to the reservoir is enabled.
[0049] In another aspect, an electrical heating system disposed within at least one of the injector and production wells 10, 20, at least partially contributes to heating of the interwell region 15. After the interwell region 15 has been heated to effect, SAGD is conducted, and SAGD includes injecting steam from the injection well 10 into the oil sands reservoir 30 for mobilizing bitumen within the oil sands reservoir 30 such that the mobilized bitumen is conducted through the interwell region 15 to the production well 20, and recovering the mobilized bitumen through the production well 20. While SAGD is being conducted, a problem may be detected requiring well intervention. Well intervention may be required, for example, to replace downhole equipment or instrumentation, such as submersible pumps, long tubing, plugged components, or optical fibre. In response to the detecting of the problem, SAGD is suspended so as to permit well intervention. After the suspending of SAGD, wellbore fluids within one or both of the wells 10, 20 may be conducted to the surface by electrically heating the wellbore fluids with the electrical heating system, such that the wellbore fluids are vaporized and are conducted through the respective well 10 or 20 to the surface 5. In some embodiments, for example, the electrical heating system may have also been used to heat the steam being supplied to the injection well 10 during SAGD. By enabling conduction of the wellbore fluids in this manner, use of pumping units or other lifting mechanism can be avoided. As well, removal of the wellbore fluids using electrical heaters is more effective than by using pumping units or other lift mechanisms, and thereby mitigates the risk of possible undesirable chemical reactions between residual wellbore fluids and fluids being introduced to the wellbore during well intervention.
[0050] In some embodiments, for example, the electrical heating is by an electrical heating system. In some of these embodiments, for example, an electrical heating system is disposed in one or both of the wells 10. In some of these embodiments, for example, the electrical heating system includes a heater cable. The heater cable includes a wire surrounded by insulation (e.g.
mineral insulation) and disposed within a metallic sheath. The wire is electrically coupled to a power source and a controller and, in this respect, is configured to effect heating of the interwell region 15 by conduction. An example of a suitable heater cable is a mineral-insulated ("MI") heater cable 70. Referring to Figure 2, a MI heater cable 70 includes an electrically conducting core 72, surrounded by a metallic sheath 74 (for example, a 304L sheath) with a mineral insulation layer 76 (for example, magnesium oxide) disposed between the metallic sheath 74 and the core 72. In some embodiments, for example, the heater cable 70 can include relatively hotter and relatively colder sections. This is enabled by using different materials in different sections of the cable. In this respect, by having relatively hotter and relatively colder section, different heating rates can be provided for different portions of the interwell region 15 in some embodiments.
[0051] Referring to Figure 3, in some of these embodiments, for example, the heater cable is deployed within a coiled tube 60. Referring to Figures 4 and 5, in some embodiments, for example, multiple cables 70 are deployed within the coiled tube 60. In some embodiments, for example, the cables 70 are mounted to a support rod 80 for maintaining positioning the cables 70. In the illustrated embodiment, for example, the heater cable is a three (3) phase heater consisting of three (3) single conductor MI heater cables 70 disposed in a coiled tube 60 that is deployed from a reel 90 disposed on the surface 5. The MI heater cables 70 are assembled into complete heater units by installing a wye splice 100 at the bottom of the cables 70 for forming a dielectrically insulated connection.
[0052] Other forms of electrical heating devices can be used, and are not limited to those discussed herein.
[0053]
Reference throughout the specification to "one embodiment," "an embodiment,"
"some embodiments," "one aspect," "an aspect," or "some aspects" means that a particular feature, structure, method, or characteristic described in connection with the embodiment or aspect is included in at least one embodiment of the present invention. In this respect, the appearance of the phrases "in one embodiment" or "in an embodiment" or "in some embodiments" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, methods, or characteristics may be combined in any suitable manner in one or more embodiments.
[0054] Each numerical value should be read once as modified by the term "about" (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the sumrnary arid this detailed description, it should be understood that a concentration range listed or described as being useful, suitable, or the like, is intended that any and every concentration within the range, including the end points, is to be considered as having been stated. For example, "a range of from 1 to 10" is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific data points, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors have disclosed and enabled the entire range and all points within the range.
[0055] 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.
Claims (23)
1. A method of establishing fluid communication between a well pair comprising an injection well and a production well within an oil sands reservoir, the method comprising:
heating an interwell region of the oil sands reservoir disposed between the injection well and the production well, establishing fluid communication between the injection well and the production well, wherein the heating comprises:
heating the interwell region with heat generated by steam injected into at least one of the injection well and the production well, and simultaneously with heat generated by an electric heating system disposed in at least one of the injection well and the production well;
wherein heat generated by the electric heating system effects both heating of the interwell region and heating of the injected steam.
heating an interwell region of the oil sands reservoir disposed between the injection well and the production well, establishing fluid communication between the injection well and the production well, wherein the heating comprises:
heating the interwell region with heat generated by steam injected into at least one of the injection well and the production well, and simultaneously with heat generated by an electric heating system disposed in at least one of the injection well and the production well;
wherein heat generated by the electric heating system effects both heating of the interwell region and heating of the injected steam.
2. The method as claimed in claim 1, wherein the steam injected into at least one of the injection well and the production well is circulated to the surface.
3. The method as claimed in claim 1, wherein the steam injected into at least one of the injection well and the production well is injected into the reservoir.
4. The method as claimed in claim 2 or 3, wherein the steam carries a gaseous chemical additive material and condensation of the chemical additive material is mitigated by the electric heating of the steam.
5. The method as claimed in any one of claims 1 to 4, wherein the electric heating system is disposed within the production well.
6. The method as claimed in any one of claims 1 to 5 comprising continuing the electric heating after fluid communication is established in the interwell region.
7. The method as claimed in any one of claims 1 to 6, wherein the interwell region is defined within the oil sands reservoir that is disposed less than 140 metres from the surface.
8. The method as claimed in any one of claims 1 to 7 wherein the oil sands reservoir has a bitumen saturation of less than 85% and a porosity of less than 30%.
9. The method as claimed in any one of claims 1 to 8 comprising injecting steam into the reservoir after fluid communication is established in the interwell region.
10. The method as claimed in any one of claims 1 to 9 comprising producing production fluid from the oil sands reservoir via the production well, wherein the production fluid includes bitumen.
11. A method of establishing fluid communication between a well pair comprising an injection well and a production well within an oil sands reservoir, the method comprising:
heating an interwell region of the oil sands reservoir disposed between the injection well and the production well, establishing fluid communication between the injection well and the production well, wherein the heating comprises:
heating the interwell region with (i) heat generated by an electric heating system disposed in at least one of the injection well and the production well and (ii) simultaneously with heat generated by at least one other artificial source of heat that emanates heat from at least one of the injection well and the production well, wherein heat generated by the electric heating system effects both heating of the interwell region and heating of the other artificial source of heat.
heating an interwell region of the oil sands reservoir disposed between the injection well and the production well, establishing fluid communication between the injection well and the production well, wherein the heating comprises:
heating the interwell region with (i) heat generated by an electric heating system disposed in at least one of the injection well and the production well and (ii) simultaneously with heat generated by at least one other artificial source of heat that emanates heat from at least one of the injection well and the production well, wherein heat generated by the electric heating system effects both heating of the interwell region and heating of the other artificial source of heat.
12. The method as claimed in claim 11, wherein the other artificial source of heat emanates heat from the same well in which the electric heating system is disposed.
13. A method of establishing fluid communication between a well pair comprising an injection well and a production well within an oil sands reservoir, the method comprising:
heating an interwell region of the oil sands reservoir disposed between the injection well and the production well, establishing fluid communication between the injection well and the production well, wherein the heating comprises:
heating the interwell region with (i) heat generated by an electric heating system disposed in at least one of the injection well and the production well and (ii) simultaneously with heat generated by at least one other artificial source of heat that emanates heat from at least one of the injection well and the production well, wherein the other artificial source of heat comprises steam with at least one additive;
and heat generated by the electric heating system effects both heating of the interwell region and heating of the other artificial source of heat.
heating an interwell region of the oil sands reservoir disposed between the injection well and the production well, establishing fluid communication between the injection well and the production well, wherein the heating comprises:
heating the interwell region with (i) heat generated by an electric heating system disposed in at least one of the injection well and the production well and (ii) simultaneously with heat generated by at least one other artificial source of heat that emanates heat from at least one of the injection well and the production well, wherein the other artificial source of heat comprises steam with at least one additive;
and heat generated by the electric heating system effects both heating of the interwell region and heating of the other artificial source of heat.
14. The method as claimed in claim 13, wherein the additive comprises butane, propane, diesel, or a combination thereof.
15 The method as claimed in claim 14, wherein the steam carries the additive in a gaseous state and condensation of the additive is mitigated by the electric heating of the steam.
16. The method as claimed in any one of claim 13 to 15, wherein the steam and the additive are circulated to the surface.
17. The method as claimed in any one of claim 13 to 15, wherein the steam and the additive are injected into the reservoir.
18. The method as claimed in any one of claims 11 to 17, wherein the electric heating system is disposed within the production well.
19. The method as claimed in any one of claims 11 to 18 comprising continuing the electric heating after fluid communication is established in the interwell region.
20. The method as claimed in any one of claims 11 to 19, wherein the interwell region is defined within the oil sands reservoir that is disposed less than 140 metres from the surface.
21. The method as claimed in any one of claims 11 to 20, wherein the oil sands reservoir has a bitumen saturation of less than 85% and a porosity of less than 30%.
22. The method as claimed in any one of claims 11 to 21 comprising injecting steam into the reservoir after fluid communication is established in the interwell region.
23. The method as claimed in any one of claims 11 to 22 comprising producing production fluid from the oil sands reservoir via the production well, wherein the production fluid includes bitumen.
Priority Applications (1)
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|---|---|---|---|
| CA3088468A CA3088468C (en) | 2014-03-10 | 2014-03-21 | Methods for establishing fluid communication between a sagd well pair |
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| US201461950457P | 2014-03-10 | 2014-03-10 | |
| US61/950,457 | 2014-03-10 | ||
| US201461968247P | 2014-03-20 | 2014-03-20 | |
| CA2846924A CA2846924A1 (en) | 2014-03-10 | 2014-03-20 | Methods for establishing fluid communication between a sagd well pair |
| CA2,846,924 | 2014-03-20 | ||
| US61/968,247 | 2014-03-20 | ||
| CA2847141A CA2847141C (en) | 2014-03-10 | 2014-03-21 | Methods for establishing fluid communication between a sagd well pair |
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