Assignee:
Exxon Production Research Company - Houston TX
International Classification:
E21B 4300
Abstract:
The invention described here is a method for using produced fluid compositions to decide how to modify injection/production strategies in oil recovery processes that involve injection of non-aqueous recovery agents ("Injectant"). The procedure is based on the premise that once a given zone is swept by injectant, most subsequent hydrocarbon recovery from that zone will occur by vaporization or extraction into the injectant. Because only the most volatile hydrocarbon components can be extracted, hydrocarbons produced by displacement can be distinguished from those produced by extraction by examining the hydrocarbon composition. Heavy, non-volatile components are recovered only by displacement. The disclosed method determines quantities of displaced vs. extracted hydrocarbons by comparing the produced hydrocarbon composition to that of the original in-place oil.