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 INITIALLY CONTACT A PORTION OF THE RESERVOIR OIL ADJACENT THE INJECTION WELL AND WILL BE ABSORBED BY SUCH PORTION OF THE RESERVOIR OIL TO ESTABLISH A ZONE OF CONTRACT WHICH ADVANCES FROM SAID INJECTION WELL IN THE DIRECTION OF THE PRODUCTION WELL WHILE THE INJECTION OF SAID NORMALLY GASEOUS HYDROCARBONS IS CONTINUED, SAID PREDETERMINED PRESSURE BEING GREAT ENOUGH TO MAINTAIN ON SAID RESERVOIR A PRESSURE WITHIN THE PRESSURE RANGE OF 3000 TO 6000 P. S. I. AND WHICH ALSO IS AT LEAST GREATER THAN THE ORIGINAL SATURATION PRESSURE OF THE LIQUID OIL SUCH THAT THE PORTION OF THE RESERVOIR AHEAD OF THE ADVANCING ZONE OF CONTACT WILL BE MAINTAINED SUBSTANTIALLY FILLED WITH THE LIQUID OIL PHASE TO THE EXCLUSION OF ANY SEPARATE GASEOUS PHASE, AND SIMULTANEOUSLY WITHDRAWING FROM THE PRODUCTION WELL THE 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 INITIALLY CONTACT A PORTION OF THE RESERVOIR OIL ADJACENT THE INJECTION WELL AND WILL BE ABSORBED BY SUCH PORTION OF THE RESERVOIR OIL TO ESTABLISH A ZONE OF CONTRACT WHICH ADVANCES FROM SAID INJECTION WELL IN THE DIRECTION OF THE PRODUCTION WELL WHILE THE INJECTION OF SAID NORMALLY GASEOUS HYDROCARBONS IS CONTINUED, SAID PREDETERMINED PRESSURE BEING GREAT ENOUGH TO MAINTAIN ON SAID RESERVOIR A PRESSURE WITHIN THE PRESSURE RANGE OF 3000 TO 6000 P. S. I. AND WHICH ALSO IS AT LEAST GREATER THAN THE ORIGINAL SATURATION PRESSURE OF THE LIQUID OIL SUCH THAT THE PORTION OF THE RESERVOIR AHEAD OF THE ADVANCING ZONE OF CONTACT WILL BE MAINTAINED SUBSTANTIALLY FILLED WITH THE LIQUID OIL PHASE TO THE EXCLUSION OF ANY SEPARATE GASEOUS PHASE, AND SIMULTANEOUSLY WITHDRAWING FROM THE PRODUCTION WELL THE RESERVOIR OIL IN THE LIQUID PHASE.