Hydrocarbon recovery control system and method

Abstract

The present disclosure describes a system, method and computer readable medium capable of dynamically managing a hydrocarbon recovery operation. The hydrocarbon recovery operation may utilize an injection well and a production well. Proportional integral derivative controller(s) may be utilized to control injection processes (for the injection well) and/or production processes (for the production well) using temperature and/or pressure data obtained from the formation. One or more production tubulars may be equipped with inflow control devices capable of controlling the flow of hydrocarbons from the formation into the production well. In one embodiment, the PID controller(s) may adjust the positioning of the injection tubing strings and/or production tubulars within their respective wells. A graphic user interface may be provided to allow users to adjust and/or customize recovery operation parameters.

What is claimed is: 
     
         1 . A computer implemented method of controlling a hydrocarbon recovery operation comprising:
 receiving temperature data pertaining to a well pair comprising an injection well and a production well;   utilizing the temperature data, determining a temperature difference between a first section of the well pair and a second section of the well pair;   generating an error term expressing the difference between the determined temperature difference and a target temperature difference;   incorporating the error term into a control function having one or more control variables; and   using one or more Proportional Integral Derivative (PID) controllers associated with the injection well, controlling the injection of stimulating fluid into the injection well utilizing one or more of the control variables.   
     
     
         2 . The computer implemented method of  claim 1 , wherein the first section of the well pair is located inside the injection well and the second section of the well pair is located inside the production well. 
     
     
         3 . The computer implemented method of  claim 1 , wherein the injection well further comprises a plurality of injection tubing strings and wherein the position of at least one of the injection tubing strings within the injection well is moved based upon one or more of the control variables. 
     
     
         4 . The computer implemented method of  claim 1 , wherein the production well further comprises a plurality of inflow control devices (ICDs) operative to control the flow of production fluids into the production well. 
     
     
         5 . The computer implemented method of  claim 4 , wherein the operation of one or more of the ICDs is controlled by a PID controller associated with a first production tubing string of the production well. 
     
     
         6 . The computer implemented method of  claim 5 , wherein the control variables further comprise a time constant and wherein the time constant utilized by the PID controller in the first production tubing string is greater than the time constant utilized by the PID controllers associated with the injection well. 
     
     
         7 . The computer implemented method of  claim 5 , wherein the control variables further comprise a proportionality constant and wherein the proportionality constant utilized by the PID controller in the first production tubing string is less than the proportionality constant utilized by the PID controllers associated with the injection well. 
     
     
         8 . The computer implemented method of  claim 1 , wherein the target temperature difference is between 2° C. and 5° C. 
     
     
         9 . The computer implemented method of  claim 1 , further comprising:
 excluding temperature data from the error term when the temperature data is below a threshold value.   
     
     
         10 . The computer implemented method of  claim 1 , wherein an average temperature is used to determine the temperature difference between the first section of the well pair and the second section of the well pair. 
     
     
         11 . The computer implemented method of  claim 1 , wherein the temperature data is obtained using an array of temperature sensors or a fiber optic distributed temperature sensor. 
     
     
         12 . The computer implemented method of  claim 1 , wherein the stimulating fluid comprises saturated steam. 
     
     
         13 . A hydrocarbon recovery control system comprising:
 an injection well and a production well that traverse a subterranean formation, wherein the injection well is positioned in the formation above and generally parallel to the production well;   wherein the injection well comprises a plurality of injection tubing strings operative to supply stimulating fluid to at least a portion of the injection well and wherein the production well comprises at least one production tubing string operative to collect production fluids from the production well and transport them to the surface; and   a controller for regulating the injection rate of stimulating fluid for each injection tubing string; wherein the operation of each controller is governed by a control function utilizing an error term representing the difference between a measured interwell subcool temperature and a target interwell subcool temperature.   
     
     
         14 . The system of  claim 13 , wherein the measured interwell subcool temperature is determined using a plurality of temperature measurements obtained using an array of temperature sensors or a fiber optic distributed temperature sensor disposed within the production well. 
     
     
         15 . The system of  claim 13 , wherein at least a portion of the injection well extends generally in a horizontal direction, and at least a portion of the production well extends in an inclined manner under the injection well. 
     
     
         16 . The system of  claim 13 , wherein the production well further comprises a plurality of inflow control devices (ICDs) operative to control the flow of production fluids into the production well. 
     
     
         17 . A computer-readable storage medium for controlling a hydrocarbon recovery operation comprising instructions which, when executed, cause a computing device to:
 determine a temperature difference between a section of an injection well and a section of a production well;   generate an error term expressing the difference between the determined temperature difference and a target temperature difference;   incorporate the error term into a control function having one or more control variables; and   using one or more Proportional Integral Derivative (PID) controllers associated with the injection well, controlling the injection of stimulation fluid into the injection well utilizing one or more of the control variables.   
     
     
         18 . The computer-readable storage medium of  claim 17 , wherein the stimulating fluid comprises saturated steam. 
     
     
         19 . The computer-readable storage medium of  claim 17 , wherein the injection well further comprises a first injection tubing string terminating in a heel portion of the injection well and a second injection tubing string terminating in a toe portion of the injection well. 
     
     
         20 . The computer-readable storage medium of  claim 17 , wherein the hydrocarbon recovery operation is a Steam Assisted Gravity Drainage (SAGD) operation.