Foam assisted enhanced oil-recovery in a layered oil reservoir

摘要

A foam assisted enhanced oil recovery (EOR) method in a layered oil reservoir (1) with an upper layer(2) that is more permeable than a lower reservoir layer(3) comprises:a) injecting an aqueous liquid through an injection well(5) into the upper layer(2);b) injecting a non-aqueous fluid into the lower layer(3);c) recovering oil from the layered oil reservoir through a production well(10); and wherein:- the aqueous liquid and/or the non-aqueous fluid carries a foaming agent; and- the injection and/or production well(5,10) has a substantially horizontal permeable fluid transfer section (10A).;The generated foam may be used as a means to confine a majority of injected non-aqueous fluid, which may comprise carbon dioxide, nitrogen, methane, ethane, propane, butane and/or flue gas within the low permeable lower layer(3) and to enhance cross-flow of aqueous liquid from the high permeable upper layer (2) into the lower permeable lower layer (3) such that oil recovery from the layered oil reservoir (1) is enhanced.