Hydrocarbon recovery employing an injection well and a production well having multiple tubing strings with active feedback control

Patent metadata

Field	Value
Publication number	US-9540917-B2
Application number	US-201214238861-A
Country	US
Kind code	B2
Filing date	Aug 8, 2012
Priority date	Aug 16, 2011
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

System and method for producing fluids from a hydrocarbon reservoir where an injector well segment and parallel underlying producer well segment are both completed with slotted liners. The injector and producer segments are logically partitioned into corresponding sections to define a plurality of injector-producer section pairs. Injection tubing strings supply stimulating fluid (e.g., saturated steam) to associated sections of the injector segment for injection into the hydrocarbon reservoir. Surface-located control devices control the pressure of the stimulating fluid flowing through the respective injection tubing strings. Production tubing strings (with the aid of artificial lift) carry fluids produced from associated sections of the producer segment. A plurality of controllers is provided for the injector-producer section pairs to control at least one process variable (e.g., interwell subcool temperature) associated with respective injector-producer section pairs over time by adjusting control variables that dictate operation of the control devices for the injection tubing strings.

First claim

What is claimed is:

1. A system for producing fluids from a subterranean hydrocarbon reservoir comprising:
an injection well and a production well that traverse the hydrocarbon reservoir, wherein the injection well includes an injector segment that is completed with at least one slotted liner and the production well includes a producer segment that is completed with at least one slotted liner, wherein the injector segment of the injection well is positioned in the hydrocarbon reservoir above and generally parallel to the producer segment of the production well, wherein the injector segment of the injection well is logically partitioned into a plurality of sections and the producer segment of the production well is logically partitioned into a plurality of sections that correspond by relative location to the sections of the injector segment to define a plurality of injector-producer section pairs;
a plurality of injection tubing strings for the sections of the injector segment, wherein each injection tubing string is configured to supply stimulating fluid to an associated section of the injector segment where the stimulating fluid flows into the at least one slotted liner of the injector segment and exits through the at least one slotted liner into the hydrocarbon reservoir in the vicinity of the injector segment of the injection well;
a plurality of surface-located control devices that control head pressure of stimulating fluid flowing through the respective injector tubing strings in order to regulate the flow of stimulating fluid flowing through the injection tubing strings;
a plurality of production tubing strings for the sections of the producer segment, wherein each production tubing string is configured to carry fluids produced from an associated section of the producer segment of the production well; and
a plurality of controllers for the injector-producer section pairs, wherein each controller is configured to control at least one process variable for 2 value associated with the at least one process variable of the corresponding injector-producer section pair over time, wherein the error value is used in a control function processed by the given controller, wherein the control function is configured to minimize the error value over time by adjusting, a control variable over time, and wherein the adjusted control variable is used to control the surface-located control device for the injector tubing string that supplies stimulating fluid to the injector section of the associated injector-producer section pair.

2. The system according to claim 1 , wherein the control function processed by the given controller includes a first term, a second term and a third term, wherein the first term produces an output value that is proportional to the current error value, wherein the second term produces an output value that is proportional to the integral of the error value over time, and wherein the third term produces an output value that is proportional to the derivative of the error value at a given time.

3. The system according to claim 1 , wherein the error value calculated by each given controller is based upon a calculation wherein a target subcool temperature is subtracted from a process variable representing, a measured interwell subcool temperature.

4. The system according to claim 1 , wherein the error value calculated by each given controller is based upon a calculation involving a plurality of process variables and associated weight factors.

5. The system according to claim 4 , wherein the plurality of process variables includes one process variable representing a measured interwell subcool temperature.

6. The system according to claim 5 , wherein the plurality of process variables includes at least one other process variable representing a measured operation parameter selected from the group consisting of water-cut, Gas-Oil Ratio (GOR), and Steam-Oil Ratio (SOR).

7. The system according to claim 1 , wherein:
the injection tubing strings extend from the surface through the injection well and terminate at internal locations of the injection well that are spaced apart from one another within or near the associated section of the injector segment of the injection well; and
the production tubing strings extend from the surface through the production well and terminate at internal locations of the production well that are spaced apart from one another within or near the associated section of the producer segment of the production well.

8. The system according to claim 7 , wherein:
the sections of the injector segment include at least a heel section and a toe section, wherein the proximal end of the heel section of the injector segment is defined by the proximal end of the at least one slotted liner of the injector segment, and wherein the distal end of the toe section of the injector segment is defined by the distal end of the at least one slotted liner of the injector segment;
the sections of the producer segment include at least a heel section and a toe section, wherein the proximal end of the heel section of the producer segment is defined by the proximal end of the at least one slotted liner of the producer segment, and wherein the distal end of the toe section of the producer segment is defined by the distal end of the at least one slotted liner of the producer segment;
the injection tubing strings include a short injection tubing string and a long injection tubing string, wherein the short injection tubing string supplies stimulating fluid to the heel section of the injector segment and terminates at an internal location of the injection well at or near the proximal end of the heel section of the injector segment, and wherein the long injection tubing string supplies stimulating fluid to the toe section of the injector segment and terminates at an internal location of the injection well at or near the distal end of the toe section of the injector segment; and
the production tubing strings include a short production tubing string and a long production tubing string, wherein the short production tubing string carries fluids produced from the heel Section of the producer segment and terminates at an internal location of the production well at or near the proximal end of the heel section of the producer segment, and wherein the long production tubing string carries fluids produced from the toe section of the producer segment and terminates at an internal location of the production well at or near the distal end of the toe section of the producer segment.

9. The system according to claim 1 , wherein the hydrocarbon reservoir includes heavy oil and the plurality of injection tubing strings are configured to supply saturated steam to the associated sections of the injector segment where the steam exits through the at least one slotted liner of the injector segment into the heavy oil reservoir in the vicinity of the injector segment of the injection well in order to contribute to steam chamber development within the heavy oil reservoir.

10. The system according to claim 1 , further comprising at least one flow meter that is configured to measure flow associated with the injector well, wherein the at least one flow meter is used for feedback control of the surface-located control devices of the respective injection tubing strings.

11. The system according to claim 1 , wherein the injector segment of the injection well extends generally in a horizontal direction, and the producer segment of the production well extends in an inclined manner under the injector segment of the injection well.

12. The system according to claim 1 , wherein;
the control function processed by the given control

Assignees

• Stone Terry Wayne
• Brown George A
• Schlumberger Technology Corp

Inventors

• Stone Terry Wayne
• Brown George A

Classifications

• E21B43/12 Primary

  Methods or apparatus for controlling the flow of the obtained fluid to or in wells (E21B43/25 takes precedence; valve arrangements E21B34/00) · CPC title

• E21B43/2406

  Steam assisted gravity drainage [SAGD] · CPC title

• E21B43/2408 Primary

  SAGD in combination with other methods · CPC title

• E21B44/00

  Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions · CPC title