Oil recovery process

Claim 1

IN A METHOD OF PRODUCING OIL FROM AND UNDERGROUND RESERVOIR BY A GAS-PROPELLED, SLUG-TYPE MISCIBLE DISPLACEMENT PROCESS WHEREIN SAID SLUG COMPRISES HYDROCARBONS WHICH ARE NORMALLY GASEOUS BUT LIQUEFIABLE AT ATMOSPHERIC TEMPERATURE, THE IMPROVEMENT WHICH COMPRISES STARTING SAID PROCESS BY PRODUCING OIL FROM SAID RESERVOIR THROUGH AN OUTPUT WELL, SEPARATING A MIXTURE OF SAID HYDROCARBONS FROM SAID PRODUCED OIL SUCH THAT SAID MIXTURE WILL FORM A SINGLE FLUID PHASE WITH SAID RESERVOIR OIL AT THE TEMPERATURE AND PRESSURE OF SAID RESERVOIR, INJECTILNG SAID MIXTURE INTO SAID RESERVOIR THROUGH AN INPUT WELL SPACED FROM SAID OUTPUT WELL SO AS TO FORM A BANK OF SIA DMIXTURE IN SAID RESERVOIR IN THE VICINITY OF SAID INPUT WELL, INJECTING AT LEAST A PORTION OF THE REMAINDER OF SAID PRODUCED OIL INTO SAID RESERVOIR AND ALSO INJECTING SUCH ADDITIONAL PRESSURIZING FLUID INTO SAID RESERVOIR AS MAY BE NECESSARY DURING THE INJECTION OF SAID MIXTURE AND SAID PRODUCED OIL TO MAINTAIN SAID RESERVOIR PRESSURE.