Heavy oil recovery

Claim 1

A METHOD FOR REMOVING A HIGH-VISCOISTY OIL FROM A SUBTERRANEAN RESERVOIR PENETRATED BY AT LEAST TWO SPACED WELLS COMPRISING: (A) INJECTING A MIXTURE OF NORMALLY GASEOUS OIL SOLUBLE AND OIL INSOLUBLE COMPONENTS, SAID MIXTURE COMPRISING FROM ABOUT 10% TO ABOUT 90% OF NORMALLY GASEOUS OIL SOLUBLE COMPONENTS, INTO RESERVOIR THROUGH ONE OF SAID WELL UNTIL A BANK OF OIL IN THE VICINTY OF THAT WELL BECOMES SATURATED WITH SAID NORMALLY GASEOUS, OIL SOLUBLE COMPONENT, THUS REDUCING THE VISCOSITY OF THE OIL IN THE BANK, THE NORMALLY GASEOUS, OIL INSOLUBLE COMPONENT TRAVELLING THROUGH SAID RESERVIOR IN THE DIRECTION OF THE OFFSET WELL, THE INJECTION PRESSURE BEING IN EXCESS OF THE BUBBLE POINT OF THE OIL IN THE RESERVOIR SO THAT THE SOLUBLE COMPONENT MAY DISSOLVE IN THE OIL AND LIKEWISE SUFFICIENTLY IN EXCESS OF THE RESERVOIR PRESSURE SO AS TO ENABLE A PRESSURE GRADIENT TO BE MAINTAINED BETWEEN THE INJECTION WELL AND THE OFFSET WELL, THE TEMPERTURE OF THE NORMALLY GASEOUS OIL SOLUBLE AND INSOLUBLE COMPONENTS INJECTED BEING THAT OBTAINED DURING COMPRESSION TO INJECTION PRESSUE; (B) SUBSEQUENTLY INJECTING SAID MIXTURE OF NORMALLY GASEOUS OIL SOLUBLE AND INSOLUBLE COMPONENTS INTO THE RESERVIOR THROUGH THE OFFSET WELL SO AS TO SATURATE A BANK OF OIL IN THE VICINTY OF SAID OFFSET WELL, THEREBY REDUCING THE VISCOSITY OF OIL IN THE VICINITY NORMALLY GASEOUS OIL INSOLUBLE COMPONENT TRAVELING THROUGH SAID RESERVOIR AND DRIVING THE PREVIOUSLY FORMED BANK OF REDUCED VISCOSITY OIL IN THE VICINITY OF THE ORGINAL INJECTION WELL INTO THAT WELL-BORE; (C) REVERSING THE DIRECTION OF GAS FLOW THROUGH THE RESERVOIR WHEREEVER THE PRODUCTION RATE DECREASES SO AS TO INDICATE THAT THE BANK OF REDUCED VISCOSITY OIL IN THE VICINITY OF THE PRODUCTION WELL HAS BEEN DEPLETED, WHEREBY THE INJECTION OF THE MIXTURE OF NORMALLY GASEOUS OIL SOLUBLE AND INSOLUBE COMPONENTS SERVES TO REDUCE THE VISCOSITY OF THE OIL IN THE VICINITY OF THE WELL THEN USED AS AN INJECTION WELL WHILE SIMULTANEOUSLY PROVIDING THE DRIVING FORCE TO REMOVE REDUCED VISCOSITY OR OIL AT AN EFFICIENT PRODUCTION RATE FROM THE OFFSET WELL THEN EMPLOYED AS A PRODUCTION WELL.

Claim 2

A METHOD FOR REMOVING A HIGH-VISCOISTY OIL FROM A SUBTERRANEAN RESERVOIR PENETRATED BY AT LEAST TWO SPACED WELLS COMPRISING: (A) INJECTING A MIXTURE OF NORMALLY GASEOUS OIL SOLUBLE AND OIL INSOLUBLE COMPONENTS, SAID MIXTURE COMPRISING FROM ABOUT 10% TO ABOUT 90% OF NORMALLY GASEOUS OIL SOLUBLE COMPONENTS, INTO RESERVOIR THROUGH ONE OF SAID WELL UNTIL A BANK OF OIL IN THE VICINTY OF THAT WELL BECOMES SATURATED WITH SAID NORMALLY GASEOUS, OIL SOLUBLE COMPONENT, THUS REDUCING THE VISCOSITY OF THE OIL IN THE BANK, THE NORMALLY GASEOUS, OIL INSOLUBLE COMPONENT TRAVELLING THROUGH SAID RESERVIOR IN THE DIRECTION OF THE OFFSET WELL, THE INJECTION PRESSURE BEING IN EXCESS OF THE BUBBLE POINT OF THE OIL IN THE RESERVOIR SO THAT THE SOLUBLE COMPONENT MAY DISSOLVE IN THE OIL AND LIKEWISE SUFFICIENTLY IN EXCESS OF THE RESERVOIR PRESSURE SO AS TO ENABLE A PRESSURE GRADIENT TO BE MAINTAINED BETWEEN THE INJECTION WELL AND THE OFFSET WELL, THE TEMPERTURE OF THE NORMALLY GASEOUS OIL SOLUBLE AND INSOLUBLE COMPONENTS INJECTED BEING THAT OBTAINED DURING COMPRESSION TO INJECTION PRESSUE; (B) SUBSEQUENTLY INJECTING SAID MIXTURE OF NORMALLY GASEOUS OIL SOLUBLE AND INSOLUBLE COMPONENTS INTO THE RESERVIOR THROUGH THE OFFSET WELL SO AS TO SATURATE A BANK OF OIL IN THE VICINTY OF SAID OFFSET WELL, THEREBY REDUCING THE VISCOSITY OF OIL IN THE VICINITY NORMALLY GASEOUS OIL INSOLUBLE COMPONENT TRAVELING THROUGH SAID RESERVOIR AND DRIVING THE PREVIOUSLY FORMED BANK OF REDUCED VISCOSITY OIL IN THE VICINITY OF THE ORGINAL INJECTION WELL INTO THAT WELL-BORE; (C) REVERSING THE DIRECTION OF GAS FLOW THROUGH THE RESERVOIR WHEREEVER THE PRODUCTION RATE DECREASES SO AS TO INDICATE THAT THE BANK OF REDUCED VISCOSITY OIL IN THE VICINITY OF THE PRODUCTION WELL HAS BEEN DEPLETED, WHEREBY THE INJECTION OF THE MIXTURE OF NORMALLY GASEOUS OIL SOLUBLE AND INSOLUBE COMPONENTS SERVES TO REDUCE THE VISCOSITY OF THE OIL IN THE VICINITY OF THE WELL THEN USED AS AN INJECTION WELL WHILE SIMULTANEOUSLY PROVIDING THE DRIVING FORCE TO REMOVE REDUCED VISCOSITY OR OIL AT AN EFFICIENT PRODUCTION RATE FROM THE OFFSET WELL THEN EMPLOYED AS A PRODUCTION WELL.