Convective SAGD process

Patent metadata

Field	Value
Publication number	US-9664022-B2
Application number	US-201414572673-A
Country	US
Kind code	B2
Filing date	Dec 16, 2014
Priority date	Dec 17, 2013
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

The present disclosure describes a recovery process using injector and producer wells, each well having means for varying the axial resistance to fluid flow to provide a complementary first and second annular axial fluid flow resistance profile. The recovery mechanism includes a gravity drainage component and also includes a convective flow mechanism which operate concurrently.

First claim

What is claimed is:

1. A method of producing viscous hydrocarbons from a subterranean reservoir, comprising:
providing a first well within the subterranean reservoir wherein the well includes a first annular region, defined by an inner surface of an outer wall which has hydraulic access to the subterranean reservoir through said wall, and an outer surface of an inner wall,
providing a first axial resistance to fluid flow varier within the first annular region of the first well along at least a portion of a length of the first well, wherein a variation in axial resistance to fluid flow in the first annular region constitutes a first annular axial fluid resistance profile,
providing a second well, at least a portion of which is aligned with and spaced apart from the first well, the second well including a second annular region, defined by an inner surface of an outer wall which has hydraulic access to the subterranean reservoir through said wall, and an outer surface of an inner wall,
providing a second axial resistance to fluid flow varier within the second annular region of the second well along at least a portion of a length of the second well, wherein a variation in axial resistance to fluid flow in the second annular region constitutes a second annular axial fluid resistance profile, wherein the second annular axial fluid resistance profile is complementary to the first annular axial fluid resistance profile of the first well,
injecting one or more mobilizing fluids into the first well, said one or more mobilizing fluids flowing through the first axial resistance to fluid flow varier in the first well, and
producing one or both of the one or more mobilizing fluids and mobilized fluids, comprising the viscous hydrocarbons, from the second well through the at least a portion of the second well having second axial resistance to fluid flow varier, and operating the first well and the second well so that gravity drainage and convective displacement are employed concurrently in recovering the viscous hydrocarbons.

2. The method of claim 1 wherein the first annular axial fluid resistance profile is complementary to the second annular axial fluid resistance profile when, i) over an interval of increasing axial resistance to fluid flow in the first well there is a decreasing axial resistance to fluid flow in the second well, or ii) over an interval of decreasing axial resistance to fluid flow in the first well there is an increasing axial resistance to fluid flow in the second well.

3. The method of claim 2 wherein the amount of increase in the axial resistance to fluid flow in one well substantially corresponds to the amount of decrease in the axial resistance to fluid flow in the other well.

4. The method of claim 3 wherein the increase in axial resistance to fluid flow in the one well and the corresponding decrease in axial resistance to fluid flow in the other well are monotonic.

5. The method of claim 3 wherein the increase in axial resistance to fluid flow in the one well and/or the corresponding decrease in axial resistance to fluid flow in the other well are non-monotonic.

6. The method of claim 1 wherein the at least one of the first and second axial resistance to flow variers comprises at least one of:
a length of tubing with a progressive increase or decrease in diameter in the axial direction, wherein the progressive increase or decrease is continuous or step-wise; and
a liner, an inner surface of which defines an outer boundary of the first or second annular region, and which contains openings that penetrate a wall of the liner such that the size, shape, configuration and distribution of those openings provide a variation in annular axial fluid resistance when fluids flow in the first or second annular regions.

7. The method of claim 1 wherein the first and second axial resistance to fluid flow variers are the same or different, with the proviso that the first and second annular axial fluid resistance profiles are complementary.

8. The method of claim 1 wherein the viscous hydrocarbons are selected from the group consisting of bitumen, heavy oil, and unmobilized hydrocarbons.

9. The method of claim 1 wherein the injected fluid comprises steam, hot water, light hydrocarbons, or mixtures thereof or one or more of non-condensing gases and surfactants.

10. A system for producing hydrocarbons from a subterranean reservoir, comprising:
a first well within the subterranean reservoir wherein the first well includes a first annular region defined by an inner surface of an outer wall which is configured to have hydraulic access to the subterranean reservoir through said wall, and an outer surface of an inner wall;
a first axial resistance to fluid flow varier within the first annular region of the first well along at least a portion of a length of the first well configured to generate a variation in axial resistance to fluid flow constituting a first annular axial fluid resistance profile;
a second well within the subterranean reservoir wherein the well includes a second annular region defined by an inner surface of an outer wall which is configured to have hydraulic access to the subterranean reservoir through said wall, and an outer surface of an inner wall; and
a second axial resistance to fluid flow varier within the second annular region of the second well along at least a portion of a length of the second well, configured to generate a variation in axial resistance to fluid flow constituting a second annular axial fluid resistance profile;
wherein the second annular axial fluid resistance profile is complementary to the first annular axial fluid resistance profile.

11. The system of claim 10 wherein the first annular axial fluid resistance profile is complementary to the second annular axial fluid resistance profile when, i) over an interval of increasing axial resistance to fluid flow in the first well there is a decreasing axial resistance to fluid flow in the second well, or ii) over an interval of decreasing axial resistance to fluid flow in the first well there is an increasing axial resistance to fluid flow in the second well.

12. The system of claim 10 wherein the amount of increase in the axial resistance to fluid flow in one well substantially corresponds to the amount of decrease in the axial resistance to fluid flow in the other well.

13. The system of claim 12 wherein the increase in axial resistance to fluid flow in the one well and/or the decrease in axial resistance to fluid flow in the other well are monotonic.

14. The system of claim 12 wherein the increase in axial resistance to fluid flow in the one well and/or the decrease in axial resistance to fluid flow in the other well are non-monotonic.

15. The system of claim 10 wherein the first and second axial resistance to fluid flow variers comprises at least one of:
a length of tubing with a progressive increase or decrease in diameter in the axial direction, wherein the progressive increase or decrease is continuous or step-wise;
a liner, an inner surface of which defines an outer boundary of the first or second annular region, and which contains openings that penetrate a wall of the liner such that the size, shape, configuration and distribution of those openings provide a variation in annular axial fluid resistance when fluids flow in the first or second annular region.

16. The system of claim 10 wherein the first and second axial resistance to fluid flow variers are the same or different, with the proviso that the first and second annular axial fluid resistance profiles are complementary.

Assignees

• Cenovus Energy Inc

Inventors

• Sood Arun

Classifications

• E21B43/24

  using heat, e.g. steam injection · CPC title

• E21B43/2406 Primary

  Steam assisted gravity drainage [SAGD] · CPC title

• E21B43/305

  comprising at least one inclined or horizontal well · CPC title