Miscible type slug method of recovering crude oil from reservoirs

Claim 1

IN A METHOD OF PRODUCING OIL FROM A SUBSTERRANEAN RESERVOIR PROVIDED WITH AT LEAST ONE INJECTION WELL AND ONE PRODUCTION WELL THE STEPS WHICH COMPRISE INTRODUCING A LIQUEFIED, NORMALLY GASEOUS FLUID COMPRISING AMMONIA INTO SAID RESERVOIR THROUGH SAID INJECTION WELL AT A PRESSURE ABOVE THE VAPOR PRESSURE OF SAID AMMONIA AT RESERVOIR TEMPERATURE, THEREAFTER INTRODUCING INTO SAID RESERVOIR THROUGH SAID INJECTION WELL A DRIVING FLUID AT A PRESSUTE SUFFICIENT TO MAINTAIN SAID AMMONIA ABOVE THE VAPOR PRESSURE OF AMMONIA AT RESERVOIR TEMPERATURE AND DISPLACE SAID AMMONIA THROUGH SAID RESERVOIR IN THE DIRECTION OF SAID PRODUCTION WELL, AND WITHDRAWING FLUIDS INCLUDING SAID OIL FROM SID PRODUCTION WELL UNTIL THE EFFLUENT FLOWING THEREFROM SUBSTANTIALLY COMPRISES SAID DRIVING FLUID.