CARBON DIOXIDE FLOODING WITH A PREMIXED ZONE OF CARBON DIOXIDE AND CRUDE OIL COMPONENTS

摘要

CARBON DIOXIDE FLOODING WITH A PREMIXED TRANSITIONZONE OF CARBON DIOXIDE AND CRUDE OIL COMPONENTS(D#76,439 -F)ABSTRACTThe disclosed invention is a method of recoveringhydrocarbons by determining the critical concentrations ofvarious crude oil components to carbon dioxide to achieve firstcontact miscibility of a mixture of said crude oil components andcarbon dioxide with the underground hydrocarbons at formationtemperature and a selected pressure substantially lower thanfirst contact miscibility pressure of carbon dioxide with thehydrocarbons; injecting into the formation a premixed transitionzone slug comprising carbon dioxide and said crude oil componentsat said critical concentrations, formation temperature and saidselected pressure; and injecting a drive fluid into the formationafter the premixed transition zone slug.