Recovery of viscous petroleum materials

Claim 1

AN IMPROVED PROCESS FOR RECOVERING PETROLEUM TARS FROM SHALLOWS INCOMPETENT TAR-SAND RESERVOIRS WHERE THE DANGER OF A BLOWOUT IS IMMINENT WHEN PRESSURIZED, HEATED FLUIDS ARE INJECTED INTO THE RESERVOIR TO DISPLACE THE VISCOUS PETROLEUM TARS COMPRISING: (A) PENETRATING SUCH A SHALLOW, INCOMPETENT TAR-SAND RESERVOIR WITH AT LEAST ONE PRODUCTION WELL AND AT LEAST ONE INJECTION WELL SPACED FRO FONE ANTHER; (B) ESTABLISHING FLUID COMMUNICATION THROUGH SAID RESERVOIR BETWEEN SAID INJECTION WELL AND SAID PRODUCTION WELL; (C) INJECTING A HEATED, GASEOUS FLUID VIA SAID INJECTION WELL THROUGH SAID ESTABLISHED FLUID COMMUNICATION BETWEEN SAID INJECTION WELL AND SAID PRODUCTION WELL AT A PRESSURE SUFFICIENT TO MAINTAIN SAID FLUID COMMUNICATION BUT BELOW THE FRACTURING PRESSURE OF SAID RESERVOIR; (D) TERMINATING THE INJECTION OF SAID HEATED, GASEOUS FLUID WHEN THE PRESSURE REQUIRED FOR INJECTING IT APPROCHES SAID FRACTURING PRESSURE OF SAID FORMATION; (E) SUBSEQUENTLY INJECTING A SUBSTANTIALLY NON-COMPRESSIBLE, PETROLEUM TAR ENTRAINING LIQUID VIA SAID INJECTION WELL AND FLOWING IT THROUGH SAID ESTABLISHED FLUID COMMUNICATION BETWEEN SAID INJECTION WELL AND SAID PRODUCTION WELL AT A PRESSURE GREATER THAN THE FRACTURE PROPPING PRESSURE OF SAID FORMATION TO REMOVE PETROLEUM TAR, INGRESSING INTO SAID ESTABLISHED FLUID COMMUNICATION; AND (F) THEREAFTER CONTINUING SAID INJECTING OF SAID HEATED, GASEOUS FLUID BELOW SAID FRACTURING PRESSURE OF SAID TAR-AND RESEVOIR.