Feedback control using a simlator of a subterranean structure

Abstract

To provide feedback control in a simulation framework, any one of plural output metrics from a simulator of a subterranean structure is selected. A value for the selected output metric is received from the simulator. In response to the received value of the selected output metric and a target value of the selected output metric, at least one setting of the simulator is adjusted by a feedback controller.

What is claimed is: 
     
         1 . A method comprising:
 selecting any one of plural output metrics from a simulator associated with a subterranean structure;   receiving a value for the selected output metric from the simulator; and   in response to the received value of the selected output metric and a target value of the selected output metric, adjusting a setting of the simulator by a fuzzy logic feedback controller executed on a processor.   
     
     
         2 . The method of  claim 1  comprising determining an error value as a difference between the received value of the selected output metric and the target value, fuzzifying the error value, applying a fuzzy rule to the fuzzified error value to provide a fuzzified response, defuzzifying the response to provide a response value and adjusting the setting of the simulator based at least in part on the response value. 
     
     
         3 . The method of  claim 2  wherein the selected output metric comprises pressure and wherein the response value comprises a value for adjusting a choke setting. 
     
     
         4 . The method of  claim 1  wherein the simulator comprises a surface network model that models a fluid choke for choking fluid flow associated with the subterranean structure. 
     
     
         5 . The method of  claim 4  further comprising adjusting a fluid choke in a surface network associated with the modeled subterranean structure based at least in part on the adjusting of the setting of the simulator by the fuzzy logic feedback controller. 
     
     
         6 . The method of  claim 4  wherein the selected output metric comprises pressure and wherein the setting comprises a choke setting for the fluid choke of the surface network model. 
     
     
         7 . The method of  claim 1  wherein the simulator comprises a surface network model, wherein the target value comprises a target pressure and wherein the adjusting the setting acts to maintain the target pressure. 
     
     
         8 . The method of  claim 7  wherein the setting comprises a choke setting for a fluid choke modeled by the surface network model. 
     
     
         9 . The method of  claim 1  further comprising selecting a plurality of the plural output metrics, receiving a plurality of corresponding values for the selected plurality of output metrics, determining a plurality of error values based on the corresponding values and at least one target value, fuzzifying the plurality of error values, applying at least one fuzzy rule to the fuzzified error values to provide at least one fuzzified response, defuzzifying the at least one fuzzified response to provide at least one response value and adjusting at least one setting of the simulator based at least in part on the at least one response value. 
     
     
         10 . The method of  claim 1 , wherein the adjusted setting comprises a controllable variable that is provided as an input to the simulator, wherein the simulator is associated with multiple controllable variables, wherein a simulation of the subterranean structure performed by the simulator is based on values of the controllable variables, the method further comprising: selectively coupling any one or more of the plural output metrics from the simulator to any one or more of the controllable variables. 
     
     
         11 . The method of  claim 1 , wherein the adjusted setting comprises a controllable variable that is provided as an input to the simulator, and wherein the controllable variable comprises a variable that affects a behavior of a controllable flow entity modeled by a surface network model. 
     
     
         12 . The method of  claim 1 , wherein the output metrics are selected from among pressure, temperature, flow rate, flow volume, and phase saturation. 
     
     
         13 . A system comprising:
 a processor;   a simulator executable on the processor to simulate at least a surface network associated with at least one reservoir using a surface network model, the simulator to produce output metrics when performing a simulation, and wherein the simulator has input control variables that control the simulator; and   a fuzzy logic feedback controller executable on the processor to configurably couple any of plural ones of the output metrics to any of plural ones of the input control variables, wherein the feedback controller adjusts a particular one of the control variables in response to particular one or more output metrics that have been coupled to the particular control variable.   
     
     
         14 . The system of  claim 13 , wherein the model models at least one controllable flow entity associated with the surface network, wherein the input control variables are to control the at least one controllable flow entity. 
     
     
         15 . The system of  claim 14  wherein the at least one controllable flow entity comprises a fluid choke. 
     
     
         16 . The system of  claim 13 , wherein the simulator further comprises at least one reservoir model. 
     
     
         17 . The system of  claim 13 , wherein the output metrics are selected from among pressure, temperature, flow rate, flow volume, and phase saturation. 
     
     
         18 . An article comprising at least one computer-readable storage medium containing instructions that upon execution by a processor is to:
 receive input regarding configuration of a fuzzy logic feedback controller that is coupled to a simulator to simulate at least a surface network associated with at least one reservoir using a surface network model, wherein the received input specifies a particular one of plural output metrics from the simulator to couple to a particular one of control variables input to the simulator;   configure the fuzzy logic feedback controller according to the received input; and   operate the fuzzy logic feedback controller to couple the particular output metric to the particular control variable, wherein the fuzzy logic feedback controller receives values of the particular output metric from the simulator and adjusts the particular control variable in response to the received values of the particular output metric.   
     
     
         19 . The article of  claim 18 , wherein adjustment of the particular control variable adjusts a setting of a controllable flow entity modeled by the surface network model. 
     
     
         20 . The article of  claim 19 , wherein the controllable flow entity modeled by the surface network model comprises a fluid choke.