Method of recovering desirable petroleum hydrocarbon fractions from producing oil reservoirs

Claim 1

THE METHOD OF RECOVERING OIL FROM A RESERVOIR CONTAINING HYDROCARBONS IN THE LIQUID OIL PHASE BUT HAVING SUBSTANTIALLY NO SEPARATE GASEOUS PHASE SUCH LIQUID OIL BEING UNDERSATURATED WITH HYDROCARBON GASES AND THEREBY BEING CAPABLE OF ABSORBING NORMALLY GASEOUS HYDROCARBONS, SAID RESERVOIR HAVING IN COMMUNICATION THEREWITH AT LEAST ONE INJECTION WELL AND ONE PRODUCTION WELL, COMPRISING THE STEPS OF INJECTING INTO THE RESERVOIR THROUGH SAID INJECTION WELL NORMALLY GASEOUS HYDROCARBONS AT A PREDETERMINED PRESSURE WHEREBY SAID INJECTED GASES WILL ESSENTIALLY CONTACT A PORTION OF THE RESERVOIR OIL ADJACENT THE INJECTION WELL AND WILL BE ABSORBED SUCH PORTION OF THE RESERVOIR OIL TO ESTABLISH A ZONE OF CONTACT WHICH ADVANCES FROM SAID INJECTION WELL IN THE DIRECTION OF THE PRODUCTION WELL WHILE THE INJECTION OF SAID NORMALLY GASEOUS HYDROCARBONS IS CONTAINED, SAID PREDETERMINED PRESSURE BEING GREAT ENOUGH TO MAINTAIN ON SAID RESERVOIR A PRESSURE WHICH LIES WITHIN A PRESSURE RANGE DETERMINED BY ASCERTAINING THE CRICONDENBAR OF A MIXTURE OF SAID RESERVOIR OIL AND SAID NORMALLY GASEOUS HYDROCARBONS AND ASCERTAINING THE LOWEST PRESSURE AT WHICH A SAMPLE OF SAID NORMALLY GASEOUS HYDROCARBONS WILL DISPLACE THE ENTIRE QUANTITY OF A SAMPLE OF SAID UNDERSATURATED RESERVOIR OIL FROM A SAND CORE HAVING A LENGTH OF AT LEAST 20 FEET FILLED WITH SAID RESERVOIR OIL SAMPLE AT THE TEMPERATURE OF SAID RESERVOIR WITHOUT THE PRESENCE OF TWO SEPARATE PHASES FLOWING SIMULTANEOUSLY OUT OF SAID CORE, AND SIMULTANEOUSLY WITHDRAWING FROM SAID RESERVOIR THROUGH SAID PRODUCTION WELL RESERVOIR OIL IN THE LIQUID PHASE.

Claim 2

THE METHOD OF RECOVERING OIL FROM A RESERVOIR CONTAINING HYDROCARBONS IN THE LIQUID OIL PHASE BUT HAVING SUBSTANTIALLY NO SEPARATE GASEOUS PHASE SUCH LIQUID OIL BEING UNDERSATURATED WITH HYDROCARBON GASES AND THEREBY BEING CAPABLE OF ABSORBING NORMALLY GASEOUS HYDROCARBONS, SAID RESERVOIR HAVING IN COMMUNICATION THEREWITH AT LEAST ONE INJECTION WELL AND ONE PRODUCTION WELL, COMPRISING THE STEPS OF INJECTING INTO THE RESERVOIR THROUGH SAID INJECTION WELL NORMALLY GASEOUS HYDROCARBONS AT A PREDETERMINED PRESSURE WHEREBY SAID INJECTED GASES WILL ESSENTIALLY CONTACT A PORTION OF THE RESERVOIR OIL ADJACENT THE INJECTION WELL AND WILL BE ABSORBED SUCH PORTION OF THE RESERVOIR OIL TO ESTABLISH A ZONE OF CONTACT WHICH ADVANCES FROM SAID INJECTION WELL IN THE DIRECTION OF THE PRODUCTION WELL WHILE THE INJECTION OF SAID NORMALLY GASEOUS HYDROCARBONS IS CONTAINED, SAID PREDETERMINED PRESSURE BEING GREAT ENOUGH TO MAINTAIN ON SAID RESERVOIR A PRESSURE WHICH LIES WITHIN A PRESSURE RANGE DETERMINED BY ASCERTAINING THE CRICONDENBAR OF A MIXTURE OF SAID RESERVOIR OIL AND SAID NORMALLY GASEOUS HYDROCARBONS AND ASCERTAINING THE LOWEST PRESSURE AT WHICH A SAMPLE OF SAID NORMALLY GASEOUS HYDROCARBONS WILL DISPLACE THE ENTIRE QUANTITY OF A SAMPLE OF SAID UNDERSATURATED RESERVOIR OIL FROM A SAND CORE HAVING A LENGTH OF AT LEAST 20 FEET FILLED WITH SAID RESERVOIR OIL SAMPLE AT THE TEMPERATURE OF SAID RESERVOIR WITHOUT THE PRESENCE OF TWO SEPARATE PHASES FLOWING SIMULTANEOUSLY OUT OF SAID CORE, AND SIMULTANEOUSLY WITHDRAWING FROM SAID RESERVOIR THROUGH SAID PRODUCTION WELL RESERVOIR OIL IN THE LIQUID PHASE.