CA2847898A1 - Improvements in hydrocarbon production, in particular using gravity drainage - Google Patents
Improvements in hydrocarbon production, in particular using gravity drainage Download PDFInfo
- Publication number
- CA2847898A1 CA2847898A1 CA2847898A CA2847898A CA2847898A1 CA 2847898 A1 CA2847898 A1 CA 2847898A1 CA 2847898 A CA2847898 A CA 2847898A CA 2847898 A CA2847898 A CA 2847898A CA 2847898 A1 CA2847898 A1 CA 2847898A1
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- section
- hydrocarbons
- subsurface
- well
- producer
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- 229930195733 hydrocarbon Natural products 0.000 title claims abstract description 146
- 150000002430 hydrocarbons Chemical class 0.000 title claims abstract description 146
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 49
- 230000005484 gravity Effects 0.000 title claims abstract description 14
- 239000004215 Carbon black (E152) Substances 0.000 title claims description 10
- 239000012530 fluid Substances 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 45
- 238000002347 injection Methods 0.000 claims description 22
- 239000007924 injection Substances 0.000 claims description 22
- 239000011435 rock Substances 0.000 claims description 19
- 238000005553 drilling Methods 0.000 claims description 12
- 239000010426 asphalt Substances 0.000 claims description 10
- 239000000295 fuel oil Substances 0.000 claims description 10
- 230000001483 mobilizing effect Effects 0.000 claims description 10
- 239000003921 oil Substances 0.000 claims description 7
- 238000005259 measurement Methods 0.000 claims description 6
- 239000002904 solvent Substances 0.000 claims description 5
- 238000005304 joining Methods 0.000 claims description 4
- 239000004576 sand Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 2
- 230000008569 process Effects 0.000 abstract description 13
- 230000015572 biosynthetic process Effects 0.000 description 11
- 238000005755 formation reaction Methods 0.000 description 11
- 238000010796 Steam-assisted gravity drainage Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 3
- 230000037361 pathway Effects 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000035508 accumulation Effects 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- -1 heavy oil or bitumen Chemical class 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 238000010420 art technique Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/16—Enhanced recovery methods for obtaining hydrocarbons
- E21B43/24—Enhanced recovery methods for obtaining hydrocarbons using heat, e.g. steam injection
- E21B43/2406—Steam assisted gravity drainage [SAGD]
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
Various methods and apparatus are described for producing hydrocarbons from the Earth's subsurface. The production may take place under a gravity drainage process.
In certain variants, there is provided apparatus which includes a section of a first well for injecting a fluid into the subsurface to mobilise the hydrocarbons, and a section of a multilateral second well being arranged adjacent to the injector section, for producing the mobilised hydrocarbons.
In certain variants, there is provided apparatus which includes a section of a first well for injecting a fluid into the subsurface to mobilise the hydrocarbons, and a section of a multilateral second well being arranged adjacent to the injector section, for producing the mobilised hydrocarbons.
Description
Improvements in hydrocarbon production, in particular using gravity drainage Field of the invention The present invention relates to the field of hydrocarbon production, in particular to methods and apparatus for producing hydrocarbons from the subsurface of the Earth.
More specifically, the invention in certain embodiments relates to hydrocarbon reservoirs comprising heavy oil or bitumen and producing hydrocarbons therefrom by gravity drainage.
Background In order to produce hydrocarbons from the Earth's subsurface, wells are provided that extend from a well head at the surface into a reservoir region of the subsurface where the hydrocarbons have accumulated. Typically, the hydrocarbons are in the form of fluid, such as oil or gas, which is able to flow freely under natural pressure conditions into and up through the well to the surface.
However, hydrocarbons comprising extra heavy oil or bitumen will not flow easily using solely pressure drive, as is the case in many subsurface hydrocarbon accumulations around the world. These kinds of hydrocarbons are viscous, sticky substances that tend to adhere to the matrix of the rock formation in the subsurface. In order to produce such hydrocarbons, it is typically sought to treat the rock formation in order to mobilise the hydrocarbons and allow them to flow and be produced through a well.
There are a number of techniques for mobilising and producing the mobilised hydrocarbons from the subsurface. Gravity-controlled and thermal processes may be favoured, and steam-assisted gravity drainage (SAGD) is one such process that is often favoured for bitumen reservoirs.
In SAGD, an injection well ("injector") and a production well ("producer") cooperate to mobilise and produce hydrocarbons. The producer is arranged to produce hydrocarbons that the injector has served to mobilise. The injector and the producer have respective well heads at surface, and wellbores which extend into the subsurface and penetrate the reservoir. The wellbores have respective injector and producer
More specifically, the invention in certain embodiments relates to hydrocarbon reservoirs comprising heavy oil or bitumen and producing hydrocarbons therefrom by gravity drainage.
Background In order to produce hydrocarbons from the Earth's subsurface, wells are provided that extend from a well head at the surface into a reservoir region of the subsurface where the hydrocarbons have accumulated. Typically, the hydrocarbons are in the form of fluid, such as oil or gas, which is able to flow freely under natural pressure conditions into and up through the well to the surface.
However, hydrocarbons comprising extra heavy oil or bitumen will not flow easily using solely pressure drive, as is the case in many subsurface hydrocarbon accumulations around the world. These kinds of hydrocarbons are viscous, sticky substances that tend to adhere to the matrix of the rock formation in the subsurface. In order to produce such hydrocarbons, it is typically sought to treat the rock formation in order to mobilise the hydrocarbons and allow them to flow and be produced through a well.
There are a number of techniques for mobilising and producing the mobilised hydrocarbons from the subsurface. Gravity-controlled and thermal processes may be favoured, and steam-assisted gravity drainage (SAGD) is one such process that is often favoured for bitumen reservoirs.
In SAGD, an injection well ("injector") and a production well ("producer") cooperate to mobilise and produce hydrocarbons. The producer is arranged to produce hydrocarbons that the injector has served to mobilise. The injector and the producer have respective well heads at surface, and wellbores which extend into the subsurface and penetrate the reservoir. The wellbores have respective injector and producer
2 sections that are arranged horizontally, with horizontal long axes, in the reservoir region. The horizontal injector and producer sections are arranged adjacent to each other with the injector section above the producer section. The injector and producer sections are typically placed near the bottom of the reservoir. Using the injector well, steam is carried into the injector section and injected into the formation.
The injector section typically has openings along the length of the section to direct steam radially out of the injector section and into the surrounding formation. This injection of steam generates a high-temperature vapour or steam chamber which heats the surrounding bitumen, thus reducing its viscosity and allowing it to drain by gravity into the producer section located below. The producer section typically has pathways (e.g.
apertures, inlets, perforations, flow control devices or the like) along its length, which may function to permit and guide flow from the formation radially into the wellbore of the producer section. The vapour or steam chamber will be understood to be the region of the subsurface rock formations into which steam has penetrated for mobilising hydrocarbons.
Typically, more than one such set of adjacent injector and producer sections is used for drainage, in order to provide "good" coverage and productivity from a given reservoir.
A problem associated with this is how to do this efficiently, and maximise recovery. In particular, as injection of steam progresses, the vapour and/or steam from each injector section rises such that the chambers grow upwards vertically and laterally.
Eventually, the steam chambers from the injector sections merge together and coalesce, and hydrocarbons are mobilised in the region between adjacent injector-producer sets. A
particular challenge is to place and operate wells appropriately to extract the hydrocarbons mobilised in this way. It is recognised that simply applying multiple sets of injectors and producers as described above across the reservoir region may not be sufficient, or may be prohibitively expensive, and thus uneconomic. The practice of drilling an additional well from the surface between such sets at later stages of production can reportedly increase production and improve recovery performance, but is similarly not without significant upfront cost. A suggestion for how such wells may be configured for the production of hydrocarbons in a gravity drainage process is described in the patent publication US7556099 (EnCana). The patent publication US2012/0285700 (Imperial) describes a technique whereby a region containing accumulations of unrecovered hydrocarbons is identified, and a well is then drilled and used to extract hydrocarbons from the identified region.
The injector section typically has openings along the length of the section to direct steam radially out of the injector section and into the surrounding formation. This injection of steam generates a high-temperature vapour or steam chamber which heats the surrounding bitumen, thus reducing its viscosity and allowing it to drain by gravity into the producer section located below. The producer section typically has pathways (e.g.
apertures, inlets, perforations, flow control devices or the like) along its length, which may function to permit and guide flow from the formation radially into the wellbore of the producer section. The vapour or steam chamber will be understood to be the region of the subsurface rock formations into which steam has penetrated for mobilising hydrocarbons.
Typically, more than one such set of adjacent injector and producer sections is used for drainage, in order to provide "good" coverage and productivity from a given reservoir.
A problem associated with this is how to do this efficiently, and maximise recovery. In particular, as injection of steam progresses, the vapour and/or steam from each injector section rises such that the chambers grow upwards vertically and laterally.
Eventually, the steam chambers from the injector sections merge together and coalesce, and hydrocarbons are mobilised in the region between adjacent injector-producer sets. A
particular challenge is to place and operate wells appropriately to extract the hydrocarbons mobilised in this way. It is recognised that simply applying multiple sets of injectors and producers as described above across the reservoir region may not be sufficient, or may be prohibitively expensive, and thus uneconomic. The practice of drilling an additional well from the surface between such sets at later stages of production can reportedly increase production and improve recovery performance, but is similarly not without significant upfront cost. A suggestion for how such wells may be configured for the production of hydrocarbons in a gravity drainage process is described in the patent publication US7556099 (EnCana). The patent publication US2012/0285700 (Imperial) describes a technique whereby a region containing accumulations of unrecovered hydrocarbons is identified, and a well is then drilled and used to extract hydrocarbons from the identified region.
3 Summary of the invention It is recognised that the practice of drilling additional wells in late stages of the production process, once steam has been injected, can suffer a risk of intersection with the active steam chamber while drilling. Multiple penetrations of the reservoir cap rock by wells can adversely affect the structure of the cap rock and the conditions in and around the reservoir. In addition, larger well pads or well pad expansion may be required to accommodate additional wells to ensure sufficient spacing between the wellheads of each SAGD injector-producer set and the well head of any additional well, so as to allow for accessibility around the wellheads during and after drilling and completion activities. However, expansion and installation of equipment at the well pad can be costly.
In light of the above, in a first aspect of the invention, there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: at least one injector well section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a first multilateral well section arranged to be provided in the subsurface adjacent to the injector well section for producing the mobilised hydrocarbons.
The apparatus may further comprise a second multilateral well section arranged to be provided in the subsurface. The second multilateral well section may have multiple uses, for example it may have different functions in different parts of a production process. In certain embodiments, the second section may be configured to produce the mobilised hydrocarbons. The second multilateral well section may be provided with inflow apparatus to let mobilised hydrocarbons flow into the section to produce the hydrocarbons. In certain embodiments, the second section may be configured to stimulate the subsurface to facilitate mobilising the hydrocarbons. The second multilateral well section may be provided with injection apparatus, e.g.
nozzles, radial pathways, or tubing perforations in a liner, to inject a fluid to stimulate the subsurface.
In certain embodiments, the second multilateral well section may be configured to perform observations of the subsurface. The second multilateral well section may have measurement apparatus, e.g. sensors, such as temperature or pressure sensors
In light of the above, in a first aspect of the invention, there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: at least one injector well section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a first multilateral well section arranged to be provided in the subsurface adjacent to the injector well section for producing the mobilised hydrocarbons.
The apparatus may further comprise a second multilateral well section arranged to be provided in the subsurface. The second multilateral well section may have multiple uses, for example it may have different functions in different parts of a production process. In certain embodiments, the second section may be configured to produce the mobilised hydrocarbons. The second multilateral well section may be provided with inflow apparatus to let mobilised hydrocarbons flow into the section to produce the hydrocarbons. In certain embodiments, the second section may be configured to stimulate the subsurface to facilitate mobilising the hydrocarbons. The second multilateral well section may be provided with injection apparatus, e.g.
nozzles, radial pathways, or tubing perforations in a liner, to inject a fluid to stimulate the subsurface.
In certain embodiments, the second multilateral well section may be configured to perform observations of the subsurface. The second multilateral well section may have measurement apparatus, e.g. sensors, such as temperature or pressure sensors
4 or the like, installed to perform measurements of subsurface properties for performing the observations.
The first multilateral well section may be provided with inflow apparatus to let mobilised hydrocarbons flow into the first section. The inflow apparatus may comprise one or more of: an inflow control device; a sand screen; a production liner; and a production packer.
The injector well section may be provided with outflow apparatus to inject the fluid flow out of the injector section and into the subsurface. The outflow apparatus comprises one or more of: an outflow control device; and injection well tubing. The outflow apparatus may comprise a nozzle, pathway, or the like for fluid from an injection tubing into the subsurface.
The second multilateral well section may be arranged to be coupled to the first multilateral well section at a joining location below the cap rock of a reservoir of the hydrocarbons in the subsurface.
The second multilateral well section may be arranged to be provided in the subsurface along a horizontal direction and in spaced apart parallel relationship with the first section. The apparatus may be adapted for producing hydrocarbons by gravity drainage.
According to a second aspect of the invention, there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: (a) injecting a fluid through at least one injector well section into the subsurface to mobilise the hydrocarbons; and (b) using a first multilateral well section to produce the mobilised hydrocarbons, the first multilateral well section being provided adjacent to the injector well section.
The method may further comprise using a second multilateral well section. The second multilateral well section is preferably coupled to the first multilateral well section below a hydrocarbon reservoir cap rock. The second multilateral well section is typically also used to produce the hydrocarbons.
The method may further comprise, prior to using the second multilateral well section to produce the hydrocarbons, measuring at least one property of the subsurface using the second multilateral well section.
The first multilateral well section may be provided with inflow apparatus to let mobilised hydrocarbons flow into the first section. The inflow apparatus may comprise one or more of: an inflow control device; a sand screen; a production liner; and a production packer.
The injector well section may be provided with outflow apparatus to inject the fluid flow out of the injector section and into the subsurface. The outflow apparatus comprises one or more of: an outflow control device; and injection well tubing. The outflow apparatus may comprise a nozzle, pathway, or the like for fluid from an injection tubing into the subsurface.
The second multilateral well section may be arranged to be coupled to the first multilateral well section at a joining location below the cap rock of a reservoir of the hydrocarbons in the subsurface.
The second multilateral well section may be arranged to be provided in the subsurface along a horizontal direction and in spaced apart parallel relationship with the first section. The apparatus may be adapted for producing hydrocarbons by gravity drainage.
According to a second aspect of the invention, there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: (a) injecting a fluid through at least one injector well section into the subsurface to mobilise the hydrocarbons; and (b) using a first multilateral well section to produce the mobilised hydrocarbons, the first multilateral well section being provided adjacent to the injector well section.
The method may further comprise using a second multilateral well section. The second multilateral well section is preferably coupled to the first multilateral well section below a hydrocarbon reservoir cap rock. The second multilateral well section is typically also used to produce the hydrocarbons.
The method may further comprise, prior to using the second multilateral well section to produce the hydrocarbons, measuring at least one property of the subsurface using the second multilateral well section.
5 The method may further comprise using the measured property to determine a location for a flow control device along a production tubing string, and providing the production tubing string in the second multilateral well section to use the second multilateral well section to produce the hydrocarbons.
The method may further comprise drilling the borehole of the second multilateral well section prior to said step of injecting the fluid.
The fluid injected may comprise any one or more of: vapour; steam; solvent;
non-condensable gas; and mixtures thereof. The subsurface may comprises oil sands.
The hydrocarbons comprise any one or more of: oil; heavy oil; extra heavy oil;
and bitumen. The method may be a method for producing hydrocarbons by gravity drainage.
According to a third aspect of the invention, there is provided a multilateral, first well comprising a producer section arranged to be provided adjacent to an injector section of a second well, to produce hydrocarbons which are mobilised by injection of a fluid into the subsurface via the injector section.
According to a fourth aspect of the invention there is provided a method of constructing the multilateral first well of the third aspect.
According to a fifth aspect of the invention there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: a section of a first well for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a section of a multilateral second well being arranged adjacent to the injector section, for producing the mobilised hydrocarbons.
According to a sixth aspect of the invention there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: injecting a fluid into the subsurface through a section of a first well to mobilise the hydrocarbons; and producing
The method may further comprise drilling the borehole of the second multilateral well section prior to said step of injecting the fluid.
The fluid injected may comprise any one or more of: vapour; steam; solvent;
non-condensable gas; and mixtures thereof. The subsurface may comprises oil sands.
The hydrocarbons comprise any one or more of: oil; heavy oil; extra heavy oil;
and bitumen. The method may be a method for producing hydrocarbons by gravity drainage.
According to a third aspect of the invention, there is provided a multilateral, first well comprising a producer section arranged to be provided adjacent to an injector section of a second well, to produce hydrocarbons which are mobilised by injection of a fluid into the subsurface via the injector section.
According to a fourth aspect of the invention there is provided a method of constructing the multilateral first well of the third aspect.
According to a fifth aspect of the invention there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: a section of a first well for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a section of a multilateral second well being arranged adjacent to the injector section, for producing the mobilised hydrocarbons.
According to a sixth aspect of the invention there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: injecting a fluid into the subsurface through a section of a first well to mobilise the hydrocarbons; and producing
6 the mobilised hydrocarbons through a section of a multilateral second well which is arranged adjacent to said section of the first well.
According to a seventh aspect of the invention there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: a first well comprising a section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a multilateral, second well comprising a section arranged to be provided in the subsurface adjacent to the injector section for producing the mobilised hydrocarbons.
According to an eighth aspect of the invention there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: (a) injecting a fluid through at least one section of a first well into the subsurface to mobilise the hydrocarbons; and (b) using a section of a multilateral, second well to produce the mobilised hydrocarbons, the section of the second well being provided adjacent to said section of the second well.
According to a ninth aspect of the invention there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: at least one injector section for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a producer section of a multilateral well for producing the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
According to a tenth aspect of the invention there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: injecting a fluid into the subsurface through at least one injector section to mobilise the hydrocarbons;
and using a producer section of a multilateral well to produce the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
According to an eleventh aspect of the invention, there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: a first well set comprising a first injector section and a first producer section arranged adjacent to the first injector section; a second set comprising a second injector and a second producer section arranged adjacent to the second injector section, the first and second injector sections being arranged to inject a fluid into the subsurface to mobilise the
According to a seventh aspect of the invention there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: a first well comprising a section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a multilateral, second well comprising a section arranged to be provided in the subsurface adjacent to the injector section for producing the mobilised hydrocarbons.
According to an eighth aspect of the invention there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: (a) injecting a fluid through at least one section of a first well into the subsurface to mobilise the hydrocarbons; and (b) using a section of a multilateral, second well to produce the mobilised hydrocarbons, the section of the second well being provided adjacent to said section of the second well.
According to a ninth aspect of the invention there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: at least one injector section for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a producer section of a multilateral well for producing the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
According to a tenth aspect of the invention there is provided a method of producing hydrocarbons from the Earth's subsurface, comprising: injecting a fluid into the subsurface through at least one injector section to mobilise the hydrocarbons;
and using a producer section of a multilateral well to produce the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
According to an eleventh aspect of the invention, there is provided apparatus for producing hydrocarbons from the Earth's subsurface, comprising: a first well set comprising a first injector section and a first producer section arranged adjacent to the first injector section; a second set comprising a second injector and a second producer section arranged adjacent to the second injector section, the first and second injector sections being arranged to inject a fluid into the subsurface to mobilise the
7 hydrocarbons, and the first and second producer sections being arranged to produce the mobilised hydrocarbons; and a third producer section arranged between the first and second sets and coupled to either of the first and second producer sections.
The third producer section may be arranged to extend horizontally and in parallel with either or both of the first and second producer sections in the subsurface.
The third producer section may be arranged to produce hydrocarbons mobilised by either or both of the injected fluid from the first injector and the second injector section, in a region between the injector sections. The third producer section may be arranged midway between the first and second producer sections. The third producer section may be arranged at the same depth within the subsurface of either of the first and second producer sections.
The third producer section may be operable to perform observations of the subsurface when not being operated to produce hydrocarbons. The third producer may be coupled to either of the first or second producer section at a joining region below the hydrocarbon reservoir cap rock. The third producer and the first or second producer section to which the third producer may be coupled may be connected to a common trunk section for connecting the coupled producer sections with a surface facility.
According to a twelfth aspect of the invention there is provided a method of providing the apparatus of any of the first, fifth, seventh, ninth or eleventh aspects of the invention.
Any of the above aspects may have further features as defined in relation to any of the other aspects. Any of the aspects may have further features as described elsewhere herein, in particular in the description, drawings and claims.
Features that are described as part of one example embodiment may be used in other embodiments where they are compatible with the other features in the other embodiment.
Description There will now be described, by way of example only, embodiments of the invention with reference to the accompanying drawings, in which:
The third producer section may be arranged to extend horizontally and in parallel with either or both of the first and second producer sections in the subsurface.
The third producer section may be arranged to produce hydrocarbons mobilised by either or both of the injected fluid from the first injector and the second injector section, in a region between the injector sections. The third producer section may be arranged midway between the first and second producer sections. The third producer section may be arranged at the same depth within the subsurface of either of the first and second producer sections.
The third producer section may be operable to perform observations of the subsurface when not being operated to produce hydrocarbons. The third producer may be coupled to either of the first or second producer section at a joining region below the hydrocarbon reservoir cap rock. The third producer and the first or second producer section to which the third producer may be coupled may be connected to a common trunk section for connecting the coupled producer sections with a surface facility.
According to a twelfth aspect of the invention there is provided a method of providing the apparatus of any of the first, fifth, seventh, ninth or eleventh aspects of the invention.
Any of the above aspects may have further features as defined in relation to any of the other aspects. Any of the aspects may have further features as described elsewhere herein, in particular in the description, drawings and claims.
Features that are described as part of one example embodiment may be used in other embodiments where they are compatible with the other features in the other embodiment.
Description There will now be described, by way of example only, embodiments of the invention with reference to the accompanying drawings, in which:
8 Figure 1 is a schematic perspective representation of apparatus according to an embodiment of the invention;
Figure 2 is an end-on cross-sectional representation of injector and producer sections arranged in a subsurface reservoir in a process of producing hydrocarbons from the reservoir, according to an embodiment of the invention;
Figure 3 is an end-on cross-sectional representation of injector and producer sections arranged in a subsurface reservoir in a process of producing hydrocarbons from a subsurface reservoir;
Figure 4A is a representation of a multilateral well in a first configuration;
Figure 4B is a cross-sectional representation of the multilateral well of Figure 4A along the line A-A;
Figure 4C is a cross-sectional representation of the multilateral well of Figure 4B along the line B-B;
Figure 4D is a cross-sectional representation of the multilateral well of Figure 4B along the line C-C; and Figure 5 is a cross-sectional representation of the multilateral well of Figure 4A in a second configuration.
With reference firstly to Figure 1, there is shown schematically apparatus 1 for use in producing hydrocarbons, such as heavy oil or bitumen, from a reservoir in the subsurface by using a gravity controlled drainage process, which for purposes of the examples below is SAGD.
The apparatus 1 has a first well 2 and a second well in the form of a multilateral well 3.
The first well 2 has a section, in the form of an "injector section" 5, for injecting a fluid into the subsurface. The section 5 has a generally horizontal trajectory in the subsurface. The multilateral well 3 comprises, at its downhole end, first and second sections 7,9 that are laterally offset with respect to one another in the subsurface
Figure 2 is an end-on cross-sectional representation of injector and producer sections arranged in a subsurface reservoir in a process of producing hydrocarbons from the reservoir, according to an embodiment of the invention;
Figure 3 is an end-on cross-sectional representation of injector and producer sections arranged in a subsurface reservoir in a process of producing hydrocarbons from a subsurface reservoir;
Figure 4A is a representation of a multilateral well in a first configuration;
Figure 4B is a cross-sectional representation of the multilateral well of Figure 4A along the line A-A;
Figure 4C is a cross-sectional representation of the multilateral well of Figure 4B along the line B-B;
Figure 4D is a cross-sectional representation of the multilateral well of Figure 4B along the line C-C; and Figure 5 is a cross-sectional representation of the multilateral well of Figure 4A in a second configuration.
With reference firstly to Figure 1, there is shown schematically apparatus 1 for use in producing hydrocarbons, such as heavy oil or bitumen, from a reservoir in the subsurface by using a gravity controlled drainage process, which for purposes of the examples below is SAGD.
The apparatus 1 has a first well 2 and a second well in the form of a multilateral well 3.
The first well 2 has a section, in the form of an "injector section" 5, for injecting a fluid into the subsurface. The section 5 has a generally horizontal trajectory in the subsurface. The multilateral well 3 comprises, at its downhole end, first and second sections 7,9 that are laterally offset with respect to one another in the subsurface
9 reservoir by a distance B in the y-direction. These sections 7,9 can be termed "laterals" or lateral sections of the multilateral well. The laterals extend along different lateral paths in the subsurface, in the x-direction. As seen in the figure, the first and second sections 7,9 are also arranged generally in parallel with each other.
Long axes of the wellbores of the sections 7, 9 are horizontal and extend in the x-direction.
The first section 7 of the multilateral well is arranged adjacent to the injector section 5.
In addition, the first lateral section 7 is arranged directly below the injector section 5, and generally in parallel thereto, being separated by a distance A in the vertical (depth) z-direction.
In order to produce hydrocarbons, a mobilising injection fluid in the form of steam is injected into the subsurface formation through the injector section 5. The injected steam mobilises the heavy oil or bitumen in the reservoir, in a so-called steam chamber or mobilised zone of the reservoir. The heavy oil or bitumen is then able to flow with condensed water from the injected steam substantially under the control of gravity to the first and second sections 7,9 where the mobilised hydrocarbons flow into the sections 7,9. In this way, the hydrocarbons are collected and produced from the subsurface using the producer section provided by the multilateral well. The first lateral section 7 and the injector section 5 may be considered, respectively, as producer and injector sections as described in the background section above, except that the producer section 7 is provided in a multilateral well.
Typically, the second section 9 is operated to produce hydrocarbons at later stages of production from the reservoir, when the steam chamber established by the injector section 5 has developed a significant distance laterally, and hydrocarbons are mobilised that are not extractable via the first lateral section 7. Prior to this, the second section 9 is typically not used or not needed to produce hydrocarbons, and hydrocarbons are produced solely via the first section 7 of the multilateral well.
The distance A can be up to 15 m, preferably between 2 to 10 m, and more preferably around 5 m as is typical for SAGD-based production. The distance B may for example be in the region of 20 to 100 m, but is typically around 50 m, although this can depend upon properties of the reservoir.
With reference next to Figure 2, the process of producing hydrocarbons using the apparatus of Figure 1 is explained in further detail. At an early stage of production from the reservoir 200, steam is injected into the subsurface reservoir using the injector section 5. The elevated temperature of the steam heats, softens and/or reduces the 5 viscosity of the extra heavy oil or bitumen, so that hydrocarbons are mobilised and can flow, allowing them to be produced. The injector section is used to generate a steam chamber to provide a mobilised hydrocarbon zone 202. The steam chamber is in effect a convective cell. At the cooler extremities of the cell, mobilised oil and condensed water are carried in downward convective flow, driven by gravity as indicated by arrows
Long axes of the wellbores of the sections 7, 9 are horizontal and extend in the x-direction.
The first section 7 of the multilateral well is arranged adjacent to the injector section 5.
In addition, the first lateral section 7 is arranged directly below the injector section 5, and generally in parallel thereto, being separated by a distance A in the vertical (depth) z-direction.
In order to produce hydrocarbons, a mobilising injection fluid in the form of steam is injected into the subsurface formation through the injector section 5. The injected steam mobilises the heavy oil or bitumen in the reservoir, in a so-called steam chamber or mobilised zone of the reservoir. The heavy oil or bitumen is then able to flow with condensed water from the injected steam substantially under the control of gravity to the first and second sections 7,9 where the mobilised hydrocarbons flow into the sections 7,9. In this way, the hydrocarbons are collected and produced from the subsurface using the producer section provided by the multilateral well. The first lateral section 7 and the injector section 5 may be considered, respectively, as producer and injector sections as described in the background section above, except that the producer section 7 is provided in a multilateral well.
Typically, the second section 9 is operated to produce hydrocarbons at later stages of production from the reservoir, when the steam chamber established by the injector section 5 has developed a significant distance laterally, and hydrocarbons are mobilised that are not extractable via the first lateral section 7. Prior to this, the second section 9 is typically not used or not needed to produce hydrocarbons, and hydrocarbons are produced solely via the first section 7 of the multilateral well.
The distance A can be up to 15 m, preferably between 2 to 10 m, and more preferably around 5 m as is typical for SAGD-based production. The distance B may for example be in the region of 20 to 100 m, but is typically around 50 m, although this can depend upon properties of the reservoir.
With reference next to Figure 2, the process of producing hydrocarbons using the apparatus of Figure 1 is explained in further detail. At an early stage of production from the reservoir 200, steam is injected into the subsurface reservoir using the injector section 5. The elevated temperature of the steam heats, softens and/or reduces the 5 viscosity of the extra heavy oil or bitumen, so that hydrocarbons are mobilised and can flow, allowing them to be produced. The injector section is used to generate a steam chamber to provide a mobilised hydrocarbon zone 202. The steam chamber is in effect a convective cell. At the cooler extremities of the cell, mobilised oil and condensed water are carried in downward convective flow, driven by gravity as indicated by arrows
10 in Figure 2 whilst steam is injected into the reservoir from the injector section 5. The figure shows a stage of production, where mobilised hydrocarbons are being produced through both the first and second sections 7,9 of the multilateral well 3. The first and second sections are therefore both acting as "producer sections" to produce hydrocarbons from the subsurface reservoir. It can be noted that at an earlier stage in the process, mobilised hydrocarbons may be produced solely through the first lateral section 7, whilst the second section 9 of the well is not active to produce hydrocarbons.
This may be the case where hydrocarbons in the vicinity of the second section are not mobilised sufficiently so as to be able to be produced through the second section 9.
The steam chamber may not have grown laterally far enough to do so effectively. As will be described below, the second section 9 can be put to a different use if not being used actively to produce hydrocarbons. It can also be noted that the second section 9, at earlier stages of the process, may not yet have been formed. This depends on requirements.
In Figure 3, an embodiment is depicted in which the second section 9 of the multilateral well is not being used to produce hydrocarbons. This will normally be in an earlier stage of the process than the situation of Figure 2. Instead, it is being used in an "injection mode" as a second injector section through which steam is injected to help mobilize the hydrocarbons in the reservoir. This can help to accelerate the formation and growth of a steam chamber and increase the region of mobilized hydrocarbons.
After a period of time, the use of the second section 9 can be switched to production mode so that it is used to produce the mobilized hydrocarbons. The multilateral well may thus be operated to switch the second section 9 to production mode, e.g., when it is determined that the steam chamber has developed sufficiently that effective production is feasible.
This may be the case where hydrocarbons in the vicinity of the second section are not mobilised sufficiently so as to be able to be produced through the second section 9.
The steam chamber may not have grown laterally far enough to do so effectively. As will be described below, the second section 9 can be put to a different use if not being used actively to produce hydrocarbons. It can also be noted that the second section 9, at earlier stages of the process, may not yet have been formed. This depends on requirements.
In Figure 3, an embodiment is depicted in which the second section 9 of the multilateral well is not being used to produce hydrocarbons. This will normally be in an earlier stage of the process than the situation of Figure 2. Instead, it is being used in an "injection mode" as a second injector section through which steam is injected to help mobilize the hydrocarbons in the reservoir. This can help to accelerate the formation and growth of a steam chamber and increase the region of mobilized hydrocarbons.
After a period of time, the use of the second section 9 can be switched to production mode so that it is used to produce the mobilized hydrocarbons. The multilateral well may thus be operated to switch the second section 9 to production mode, e.g., when it is determined that the steam chamber has developed sufficiently that effective production is feasible.
11 With further reference now to Figures 4A to 4D, an example of a multilateral well 40 is described, as may be used in the apparatus and processes described above. The well 40 has first and second sections 41, 42 comprising respective horizontal boreholes completed and fitted with a perforated liner 41s, 42s for receiving mobilized hydrocarbons therethrough from the surrounding subsurface. The first and second sections are coupled. They join together at a junction in a joining region 43 below the cap rock 50 in the subsurface. The sections connect to a common trunk section that connects the lateral sections 41, 42 to the surface. In this way, as can be seen, the sections are laterally spaced apart from each other at the downhole end, in the reservoir, and join together at an uphole location, in the joining region. The multilateral well thus branches or splays from one wellbore at the surface (e.g. at the well head) into two wellbore sections 41, 42 further downhole, in the subsurface.
Produced fluids including hydrocarbons from the first and second lateral sections 41, 42 are received and combined in the trunk section as indicated by arrows 46 and conveyed to the surface therethrough. A pump 47 is arranged in the trunk section 45 acting on the combined fluid to lift the fluids to the surface (not shown) through the production tubing 51 inside the trunk section 45 to remove the hydrocarbons from the well. The junction of the two sections must either have a level of sand control that is comparable to the production liner, or it may be provided open hole where the formation is competent.
The pump 47 is placed in its own tangent section above the junction. The tangent section is preferably a long straight section in the trunk section 45 typically of around 50 m in length. The pump can then be kept straight making it less prone to failure.
Figures 4C and 40 show the opening 48a to which the end 48b of the second section 42 is connected to the first section 41 and trunk section 45.
As exemplified in Figure 4A, by way of the multilateral well, production can take place through both the first and second lateral sections 7,9 of Figure 1, or sections 41, 42 of Figure 4A, with a common producer well head and well pump serving both sections, e.g. at the stage of process such as described in relation to Figure 3.
In Figure 5, a variant on the arrangement of Figures 4A to 4D is exemplified, whereby the multilateral well is operated to put the second lateral section 42 to a different use than production, whilst production continues through the first section 41 (e.g. as in Figure 3 above). The second lateral section 42 in this example is configured to
Produced fluids including hydrocarbons from the first and second lateral sections 41, 42 are received and combined in the trunk section as indicated by arrows 46 and conveyed to the surface therethrough. A pump 47 is arranged in the trunk section 45 acting on the combined fluid to lift the fluids to the surface (not shown) through the production tubing 51 inside the trunk section 45 to remove the hydrocarbons from the well. The junction of the two sections must either have a level of sand control that is comparable to the production liner, or it may be provided open hole where the formation is competent.
The pump 47 is placed in its own tangent section above the junction. The tangent section is preferably a long straight section in the trunk section 45 typically of around 50 m in length. The pump can then be kept straight making it less prone to failure.
Figures 4C and 40 show the opening 48a to which the end 48b of the second section 42 is connected to the first section 41 and trunk section 45.
As exemplified in Figure 4A, by way of the multilateral well, production can take place through both the first and second lateral sections 7,9 of Figure 1, or sections 41, 42 of Figure 4A, with a common producer well head and well pump serving both sections, e.g. at the stage of process such as described in relation to Figure 3.
In Figure 5, a variant on the arrangement of Figures 4A to 4D is exemplified, whereby the multilateral well is operated to put the second lateral section 42 to a different use than production, whilst production continues through the first section 41 (e.g. as in Figure 3 above). The second lateral section 42 in this example is configured to
12 stimulate the reservoir while the first lateral section 41 of the multilateral well is producing fluids (the second section 42 is not producing fluids). A tubing string 52 is run into the opening into lateral section 42 and is hydraulically isolated from the producing first section 41 with a packer 53. The tubing string 52 provides the ability to stimulate the reservoir near the lateral section 42 using a combination of injection fluids including steam, water, or solvent. In another variant, the tubing 52 may extend further into the opening and into the lateral section 42, and the reservoir may be stimulated using electrical heaters run inside the tubing and into the horizontal section of the lateral section 42. In a further option, with the lateral section 42 isolated hydraulically, it can be pressurized with an injection fluid to create a pressure drive of production fluids in the horizontal direction from the lateral towards the first section 41 being used as a producer. This will accelerate production of mobilized fluids at the lower part of the reservoir by supplementing gravity drive with pressure drive.
The first and second wells can be formed using established well construction techniques. The construction of the wells involves drilling suitable boreholes into the earth along defined trajectories and providing a suitably completed injector section and completed lateral sections of the multilateral well in the reservoir, for example as described above. A first borehole is for example drilled from the surface to provide the horizontal first section 41 of the multilateral producer. A second borehole is then drilled from the surface following along the trajectory of the first, but spaced vertically apart therefrom, to provide the injector section of the first well vertically above the first section 41 of the multilateral well. The first borehole is then re-entered and a third, side track borehole is drilled into the wall of the first borehole at an appropriate point there along for creating the second section 42 of the multilateral well. The entry point for drilling of the side track borehole is preferably selected to be below the reservoir cap rock. As such, the junction 43 is provided below the cap rock. This means that only the trunk section 45 pierces the cap rock, and it is not necessary to drill two holes through the cap rock in order to provide two lateral sections in the reservoir of the subsurface. This helps to minimize disturbances to the cap rock and helps to maintain cap rock integrity.
The multilateral well is fitted with suitable completion equipment in the boreholes of the first and second lateral sections for producing hydrocarbons as described above.
When producing through two or more lateral sections of the multilateral well, a common
The first and second wells can be formed using established well construction techniques. The construction of the wells involves drilling suitable boreholes into the earth along defined trajectories and providing a suitably completed injector section and completed lateral sections of the multilateral well in the reservoir, for example as described above. A first borehole is for example drilled from the surface to provide the horizontal first section 41 of the multilateral producer. A second borehole is then drilled from the surface following along the trajectory of the first, but spaced vertically apart therefrom, to provide the injector section of the first well vertically above the first section 41 of the multilateral well. The first borehole is then re-entered and a third, side track borehole is drilled into the wall of the first borehole at an appropriate point there along for creating the second section 42 of the multilateral well. The entry point for drilling of the side track borehole is preferably selected to be below the reservoir cap rock. As such, the junction 43 is provided below the cap rock. This means that only the trunk section 45 pierces the cap rock, and it is not necessary to drill two holes through the cap rock in order to provide two lateral sections in the reservoir of the subsurface. This helps to minimize disturbances to the cap rock and helps to maintain cap rock integrity.
The multilateral well is fitted with suitable completion equipment in the boreholes of the first and second lateral sections for producing hydrocarbons as described above.
When producing through two or more lateral sections of the multilateral well, a common
13 production pump is inserted in the common trunk section, above the point of entry of the side track. Preferably, the drilling of the third borehole for the second lateral section of the producer is performed "cold", i.e. before the formation is heated significantly by injection of steam via the injector; however, it could be drilled at a later time when the well is "warm", once the formation is heated by the injected steam. This could be beneficial if for instance the reservoir conditions indicate that a different than expected placement of the second lateral section is required.
Hence, in some embodiments, the side-track borehole is not drilled at the outset. In this case, the first stage of the production process may be performed without the second section of the producer altogether. When the development of the steam chambers and mobilisation of hydrocarbons has developed further, the second section may be drilled, by re-entering the first borehole, and drilling the side track borehole below the cap rock. Drilling cold however reduces the risk of intersection an active steam chamber.
In certain examples, rather than performing injection, the second section 9 is used to perform observations in the reservoir prior to it being used to receive and produce hydrocarbons. This would in effect be a variant on Figure 4. For example, the lateral section 9 may be provided with observation equipment such as temperature or pressure sensors or other sensors for taking measurements of pressure, temperature or other parameters, monitoring or otherwise observing conditions in the subsurface.
Thereafter, such observation equipment may be removed and production equipment installed such as sand screens, liners, production packers, flow control devices and the like for switching over to production mode. Provision of an observation section in this manner allows for a better understanding of the initial producer well flow and the steam chamber growth in the initial stage of production taking place via the first lateral section 7. The observations can assist in determining where best to place steam distribution devices or inflow control devices in the injector 5, and/or the first and second sections 7,9 of the multilateral well. For example, in the initial stage of production as depicted in Figure 3, the second section 9 may be used as an "observation section" to obtain observational data from the reservoir.
In an enhanced oil recovery process, there is the potential for injection fluids to enter the production well. This is normally controlled by adjusting the rate of production from
Hence, in some embodiments, the side-track borehole is not drilled at the outset. In this case, the first stage of the production process may be performed without the second section of the producer altogether. When the development of the steam chambers and mobilisation of hydrocarbons has developed further, the second section may be drilled, by re-entering the first borehole, and drilling the side track borehole below the cap rock. Drilling cold however reduces the risk of intersection an active steam chamber.
In certain examples, rather than performing injection, the second section 9 is used to perform observations in the reservoir prior to it being used to receive and produce hydrocarbons. This would in effect be a variant on Figure 4. For example, the lateral section 9 may be provided with observation equipment such as temperature or pressure sensors or other sensors for taking measurements of pressure, temperature or other parameters, monitoring or otherwise observing conditions in the subsurface.
Thereafter, such observation equipment may be removed and production equipment installed such as sand screens, liners, production packers, flow control devices and the like for switching over to production mode. Provision of an observation section in this manner allows for a better understanding of the initial producer well flow and the steam chamber growth in the initial stage of production taking place via the first lateral section 7. The observations can assist in determining where best to place steam distribution devices or inflow control devices in the injector 5, and/or the first and second sections 7,9 of the multilateral well. For example, in the initial stage of production as depicted in Figure 3, the second section 9 may be used as an "observation section" to obtain observational data from the reservoir.
In an enhanced oil recovery process, there is the potential for injection fluids to enter the production well. This is normally controlled by adjusting the rate of production from
14 the producer well using the artificial lift system (e.g., pump). If a situation arises where injection fluids begin to enter the production well, the pump will be slowed to decrease the amount of production fluid being removed from the reservoir. Other strategies can be employed to prevent the breakthrough of injection fluids. This includes installing flow control devices with a flow resistance that is pre-set according to predicted variations in reservoir geology or according to variations in well position (i.e., depth position or lateral position), with both factors predisposing certain sections of the well to breakthrough of injection fluids.
In the use of the multilateral well of the present invention to produce hydrocarbons, the approach can be similar. The artificial lift system remains important for maximizing the rate of production fluid removed from the well, while avoiding the breakthrough of injection fluids from occurring. Another method is to install permanent flow control devices on the pipes of the producer sections according to predicted geological variations and well position. The second section of the multilateral well is typically constructed from pipes that are 12-14 m long. Permanent flow control devices can be installed on each pipe segment, such that production rates of fluid entering the well sections can be managed at over 12-14 m increments by choosing flow control devices setting. Another strategy is to install non-permanent flow control devices on a tubing string that is run inside the producer section. A benefit of the observations from the second section of the well is that such measurements can be used for the sizing and positioning of non-permanent flow control devices installed on the tubing string.
In the multilateral well, the single pump can operate both producer sections simultaneously. Since the lateral sections of the producer are connected by the junction, pressure communication between the laterals is nearly instantaneous.
This allows bottomhole pressures in both lateral producer sections of the well to be adjusted quickly by well operating personnel for the purpose of maximizing production while avoiding injection fluids from entering the producer sections.
In practice, it is desirable to provide for multiple sets of adjacent injector and producer sections in a reservoir region in order to perform SAGD and maximise the production from the region.
In other embodiments, the multilateral well may have three or more subsurface lateral sections, not just two as described above. One of the lateral sections would then be used adjacent to and provided beneath the injector as a producer section to optimally collect mobilised hydrocarbons at the base of the steam chamber.
Further, in other embodiments, a fluid other than steam may be injected for mobilising the hydrocarbons. Such a fluid preferably heats the hydrocarbons. The fluid may comprise any one or more of: a solvent, steam mixed with a solvent, or a non-condensable gas, such as methane or the like.
Costs associated with expansion of surface facilities, and costs of adding well heads and pump equipment inside wells, in order to reach new regions of the reservoir can be reduced through the use of a multilateral well as described herein. The current concept means that two horizontal producer sections can be tied to a single wellhead, a single build section, and a single pump, which can help to reduce costs compared with prior art techniques. The costs of implementation with a multilateral well providing a producer section will be the same as for a single well (non-multilateral) SAGD
producer, except for that of adding the second horizontal section and packer to allow the added section to be opened and used for production when it is needed. Risk is reduced, as the second section can conveniently be drilled cold, at the stage of constructing the first section, rather than at a later stage when the steam chamber has developed. In summary, the invention is generally targeted at reducing well costs, while also reducing the risk of drilling near an active steam chamber.
Various modifications and improvements may be made without departing from the scope of the invention herein described.
In the use of the multilateral well of the present invention to produce hydrocarbons, the approach can be similar. The artificial lift system remains important for maximizing the rate of production fluid removed from the well, while avoiding the breakthrough of injection fluids from occurring. Another method is to install permanent flow control devices on the pipes of the producer sections according to predicted geological variations and well position. The second section of the multilateral well is typically constructed from pipes that are 12-14 m long. Permanent flow control devices can be installed on each pipe segment, such that production rates of fluid entering the well sections can be managed at over 12-14 m increments by choosing flow control devices setting. Another strategy is to install non-permanent flow control devices on a tubing string that is run inside the producer section. A benefit of the observations from the second section of the well is that such measurements can be used for the sizing and positioning of non-permanent flow control devices installed on the tubing string.
In the multilateral well, the single pump can operate both producer sections simultaneously. Since the lateral sections of the producer are connected by the junction, pressure communication between the laterals is nearly instantaneous.
This allows bottomhole pressures in both lateral producer sections of the well to be adjusted quickly by well operating personnel for the purpose of maximizing production while avoiding injection fluids from entering the producer sections.
In practice, it is desirable to provide for multiple sets of adjacent injector and producer sections in a reservoir region in order to perform SAGD and maximise the production from the region.
In other embodiments, the multilateral well may have three or more subsurface lateral sections, not just two as described above. One of the lateral sections would then be used adjacent to and provided beneath the injector as a producer section to optimally collect mobilised hydrocarbons at the base of the steam chamber.
Further, in other embodiments, a fluid other than steam may be injected for mobilising the hydrocarbons. Such a fluid preferably heats the hydrocarbons. The fluid may comprise any one or more of: a solvent, steam mixed with a solvent, or a non-condensable gas, such as methane or the like.
Costs associated with expansion of surface facilities, and costs of adding well heads and pump equipment inside wells, in order to reach new regions of the reservoir can be reduced through the use of a multilateral well as described herein. The current concept means that two horizontal producer sections can be tied to a single wellhead, a single build section, and a single pump, which can help to reduce costs compared with prior art techniques. The costs of implementation with a multilateral well providing a producer section will be the same as for a single well (non-multilateral) SAGD
producer, except for that of adding the second horizontal section and packer to allow the added section to be opened and used for production when it is needed. Risk is reduced, as the second section can conveniently be drilled cold, at the stage of constructing the first section, rather than at a later stage when the steam chamber has developed. In summary, the invention is generally targeted at reducing well costs, while also reducing the risk of drilling near an active steam chamber.
Various modifications and improvements may be made without departing from the scope of the invention herein described.
Claims (40)
1. Apparatus for producing hydrocarbons from the Earth's subsurface, comprising:
at least one injector well section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a first multilateral well section arranged to be provided in the subsurface adjacent to the injector well section for producing the mobilised hydrocarbons.
at least one injector well section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a first multilateral well section arranged to be provided in the subsurface adjacent to the injector well section for producing the mobilised hydrocarbons.
2. Apparatus as claimed in claim 1, which further comprises a second multilateral well section arranged to be provided in the subsurface, the second section being configured to produce the mobilised hydrocarbons.
3. Apparatus as claimed in claim 2, wherein the second multilateral well section is provided with inflow apparatus to let mobilised hydrocarbons flow into the section.
4. Apparatus as claimed in claim 1, which further comprises a second multilateral well section arranged to be provided in the subsurface, the second section being configured to stimulate the subsurface to facilitate mobilising the hydrocarbons.
5. Apparatus as claimed in claim 4, wherein the second multilateral well section is provided with injection apparatus to inject a fluid to stimulate the subsurface.
6. Apparatus as claimed in claim 1, which further comprises a second multilateral well section arranged to be provided in the subsurface, the second multilateral well section being configured to perform observations of the subsurface.
7. Apparatus as claimed in claim 6, wherein the second multilateral well section has measurement apparatus installed to perform measurements of subsurface properties for performing the observations.
8. Apparatus as claimed in any of claims 1 to 7, wherein the first multilateral well section is provided with inflow apparatus to let mobilised hydrocarbons flow into the first section.
9. Apparatus as claimed in claim 8, wherein the inflow apparatus comprises one or more of: an inflow control device; a sand screen; a production liner; and a production packer.
10. Apparatus as claimed in any of claim 1 to 9, wherein the injector section is provided with outflow apparatus to inject the fluid flow out of the injector section and into the subsurface.
11. Apparatus as claimed in claim 10, wherein the outflow apparatus comprises one or more of: an outflow control device; and injection well tubing.
12. Apparatus as claimed in any of claims 1 to 11, which further comprises a second multilateral well section arranged to be provided in the subsurface, and coupled to the first multilateral well section at a joining location below the cap rock of a reservoir of the hydrocarbons in the subsurface.
13. Apparatus as claimed in any of claims 1 to 12, which further comprises a second multilateral well section arranged to be provided in the subsurface, along a horizontal direction and in spaced apart parallel relationship with the first section.
14. A method of producing hydrocarbons from the Earth's subsurface, comprising:
(a) injecting a fluid through at least one injector well section into the subsurface to mobilise the hydrocarbons; and (b) using a first multilateral well section to produce the mobilised hydrocarbons, the first multilateral well section being provided adjacent to the injector well section.
(a) injecting a fluid through at least one injector well section into the subsurface to mobilise the hydrocarbons; and (b) using a first multilateral well section to produce the mobilised hydrocarbons, the first multilateral well section being provided adjacent to the injector well section.
15. A method as claimed in claim 14, which further comprises using a second multilateral well section to produce the hydrocarbons.
16. A method as claimed in claim 15, wherein the second multilateral well section is coupled to the first multilateral well section below a hydrocarbon reservoir cap rock.
17. A method as claimed in claim 15 or 16, which further comprises, prior to using the second multilateral well section to produce the hydrocarbons, measuring at least one property of the subsurface using the second multilateral well section.
18. A method as claimed in any of claims 15 to 17, which further comprises using the measured property to determine a location for a flow control device along a production tubing string, and providing the production tubing string in the second multilateral well section to use the second multilateral well section to produce the hydrocarbons.
19. A method as claimed in any of claims 15 to 18, which further comprises drilling the borehole of the second multilateral well section prior to said step of injecting the fluid.
20. A method as claimed in any of claims 14 to 19, wherein the fluid comprises any one or more of: vapour; steam; solvent; non-condensable gas; and mixtures thereof.
21. A method as claimed in any of claims 14 to 20, wherein the hydrocarbons comprise any one or more of: oil; heavy oil; extra heavy oil; and bitumen.
22. A method as claimed in any of claims 14 to 21, wherein the subsurface comprises oil sands.
23. A method as claimed in any of claims 14 to 22, for producing hydrocarbons by gravity drainage.
24. A multilateral, first well comprising a producer section arranged to be provided adjacent to an injector section of a second well, to produce hydrocarbons which are mobilised by injection of a fluid into the subsurface via the injector section.
25. A method of constructing the multilateral first well as claimed in claim 24.
26. A method of providing the apparatus as claimed in any of claims 1 to 14 for producing hydrocarbons.
27. Apparatus for producing hydrocarbons from the Earth's subsurface, comprising:
a section of a first well for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a section of a multilateral second well being arranged adjacent to the injector section, for producing the mobilised hydrocarbons.
a section of a first well for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a section of a multilateral second well being arranged adjacent to the injector section, for producing the mobilised hydrocarbons.
28. A method of producing hydrocarbons from the Earth's subsurface, comprising:
injecting a fluid into the subsurface through a section of a first well to mobilise the hydrocarbons; and producing the mobilised hydrocarbons through a section of a multilateral second well which is arranged adjacent to said section of the first well.
injecting a fluid into the subsurface through a section of a first well to mobilise the hydrocarbons; and producing the mobilised hydrocarbons through a section of a multilateral second well which is arranged adjacent to said section of the first well.
29. Apparatus for producing hydrocarbons from the Earth's subsurface, comprising:
a first well comprising a section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a multilateral, second well comprising a section arranged to be provided in the subsurface adjacent to the injector section for producing the mobilised hydrocarbons.
a first well comprising a section arranged to be provided in the subsurface for injecting a fluid for mobilising the hydrocarbons; and a multilateral, second well comprising a section arranged to be provided in the subsurface adjacent to the injector section for producing the mobilised hydrocarbons.
30. A method of producing hydrocarbons from the Earth's subsurface, comprising:
(a) injecting a fluid through at least one section of a first well into the subsurface to mobilise the hydrocarbons; and (b) using a section of a multilateral, second well to produce the mobilised hydrocarbons, the section of the second well being provided adjacent to said section of the second well.
(a) injecting a fluid through at least one section of a first well into the subsurface to mobilise the hydrocarbons; and (b) using a section of a multilateral, second well to produce the mobilised hydrocarbons, the section of the second well being provided adjacent to said section of the second well.
31. Apparatus for producing hydrocarbons from the Earth's subsurface, comprising:
at least one injector section for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a producer section of a multilateral well for producing the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
at least one injector section for injecting a fluid into the subsurface to mobilise the hydrocarbons; and a producer section of a multilateral well for producing the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
32. A method of producing hydrocarbons from the Earth's subsurface, comprising:
injecting a fluid into the subsurface through at least one injector section to mobilise the hydrocarbons; and using a producer section of a multilateral well to produce the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
injecting a fluid into the subsurface through at least one injector section to mobilise the hydrocarbons; and using a producer section of a multilateral well to produce the mobilised hydrocarbons, the producer section being arranged adjacent to the injector section.
33. Apparatus for producing hydrocarbons from the Earth's subsurface, comprising:
a first well set comprising a first injector section and a first producer section arranged adjacent to the first injector section;
a second set comprising a second injector and a second producer section arranged adjacent to the second injector section, the first and second injector sections being arranged to inject a fluid into the subsurface to mobilise the hydrocarbons, and the first and second producer sections being arranged to produce the mobilised hydrocarbons; and a third producer section arranged between the first and second sets and coupled to either of the first and second producer sections.
a first well set comprising a first injector section and a first producer section arranged adjacent to the first injector section;
a second set comprising a second injector and a second producer section arranged adjacent to the second injector section, the first and second injector sections being arranged to inject a fluid into the subsurface to mobilise the hydrocarbons, and the first and second producer sections being arranged to produce the mobilised hydrocarbons; and a third producer section arranged between the first and second sets and coupled to either of the first and second producer sections.
34. Apparatus as claimed in claim 33, wherein the third producer section is arranged to extend horizontally and in parallel with either or both of the first and second producer sections in the subsurface.
35. Apparatus as claimed in claim 34, wherein the third producer section is arranged to produce hydrocarbons mobilised by either or both of the injected fluid from the first injector and the second injector section, in a region between the injector sections.
36. Apparatus as claimed in any of claims 33 to 35, wherein the third producer section is arranged midway between the first and second producer sections.
37. Apparatus as claimed in any of claims 33 to 36, wherein the third producer section is arranged at the same depth within the subsurface of either of the first and second producer sections.
38. Apparatus as claimed in any of claims 33 to 37 wherein the third producer section is operable to perform observations of the subsurface when not being operated to produce hydrocarbons.
39. Apparatus as claimed in any of claims 33 to 40, wherein the third producer is coupled to either of the first or second producer section at a joining region below the hydrocarbon reservoir cap rock.
40. Apparatus as claimed in any of claims 33 to 39, wherein the third producer and the first or second producer section to which the third producer is coupled are connected to a common trunk section for connecting the coupled producer sections with a surface facility.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2847898A CA2847898A1 (en) | 2014-03-31 | 2014-03-31 | Improvements in hydrocarbon production, in particular using gravity drainage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2847898A CA2847898A1 (en) | 2014-03-31 | 2014-03-31 | Improvements in hydrocarbon production, in particular using gravity drainage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2847898A1 true CA2847898A1 (en) | 2015-09-30 |
Family
ID=54250510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2847898A Abandoned CA2847898A1 (en) | 2014-03-31 | 2014-03-31 | Improvements in hydrocarbon production, in particular using gravity drainage |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2847898A1 (en) |
-
2014
- 2014-03-31 CA CA2847898A patent/CA2847898A1/en not_active Abandoned
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| Date | Code | Title | Description |
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| EEER | Examination request |
Effective date: 20190205 |
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| FZDE | Discontinued |
Effective date: 20220530 |
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| FZDE | Discontinued |
Effective date: 20220530 |