ENHANCED OIL RECOVERY EMPLOYING BLEND OF CARBON DIOXIDE INERT GAS AND INTERMEDIATE HYDROCARBONS

摘要

Oil may be recovered from dipping reservoirs by a conditionally miscible oil recovery process in which a gaseous, carbon dioxide-containing fluid is injected up-dip to displace petroleum downward in a conditionally miscible, gravity-stabilized displacement process. Carbon dioxide-containing blending stock is mixed with an inert gas such as methane or nitrogen in order to reduce its density sufficiently to increase the critical velocity of the displacement process. By increasing the critical velocity, the time required to deplete a reservoir is decreased significantly. Sufficient intermediate hydrocarbons are added to the mixture of carbon dioxide and inert gas to insure that the mixture injected into the formation is conditionally miscible at formation temperature and pressure.