Autonomous valve, system, and method

Abstract

A method for controlling a Steam Assisted Gravity Drainage (SAGD) System including injecting steam through an injector well into a formation in thermal contact with the system; automatically admitting, reducing or denying entry of fluid to a producer well through a valve based upon both of temperature and pressure. Further, a Steam Assisted Gravity Drainage (SAGD) System including a producer well having a valve that automatically admits, reduces or denies entry of fluid to a producer well through the valve based upon both of temperature and pressure.

What is claimed is: 
     
         1 . A method for controlling a Steam Assisted Gravity Drainage (SAGD) System comprising:
 injecting steam through a well into a formation in thermal contact with the system;   automatically admitting, reducing or denying fluid flow out of the formation through a valve based upon both of temperature and pressure.   
     
     
         2 . The method as claimed in  claim 1  wherein the automatically admitting, reducing or denying entry of fluid is by enlarging or reducing a flow passage of the valve. 
     
     
         3 . The method as claimed in  claim 2  wherein the enlarging or reducing is by retracting or extending a piston relative to the flow passage of the valve. 
     
     
         4 . The method as claimed in  claim 1  wherein the automatically admitting, reducing or denying entry of fluid is in response to pressure and temperature on a graph intersecting at a point on a saturation curve line for a particular fluid in the valve different than a point on the saturation curve line where temperature and pressure intersected immediately previously. 
     
     
         5 . The method as claimed in  claim 3  wherein the extending occurs when temperature and pressure intersect on the saturation curve line at a point consistent with more steam evolution than the point at which temperature and pressure intersected immediately previously. 
     
     
         6 . The method as claimed in  claim 3  wherein the retracting occurs when temperature and pressure intersect on the saturation curve line at a point consistent with less steam evolution than the point at which temperature and pressure intersected immediately previously. 
     
     
         7 . The method as claimed in  claim 3  further including biasing the piston to a position. 
     
     
         8 . The method as claimed in  claim 7  wherein the biasing is in the direction of the extending of the piston. 
     
     
         9 . The method as claimed in  claim 7  wherein the biasing is in the direction of the retracting of the piston. 
     
     
         10 . The method as claimed in  claim 1  further comprising selecting a fluid to be resident in the valve, the fluid having a particular saturation curve. 
     
     
         11 . The method as claimed in  claim 1  wherein the injecting is through an injector well. 
     
     
         12 . The method as claimed in  claim 1  wherein the automatically admitting, reducing or denying fluid flow is to a producer well. 
     
     
         13 . A Steam Assisted Gravity Drainage (SAGD) System comprising:
 a wellbore system in a subsurface formation, the wellbore system having a valve that automatically admits, reduces or denies entry of fluid to a production flow through the valve based upon both of temperature and pressure.