| 摘要 |
The invention disclosed herein is a method for producing oil from a reservoir after predetermining its residual oil saturation, Sorm. Such a method would displace a hydrocarbon fluid in a subterranean formation using a substantially non-aqueous displacement fluid after a waterflood. The non-aqueous displacement fluid can be introduced as a single bank, in alternating sequence with water, or by other means. The method predetermines Sorm using the difference in the solubility parameters between the hydrocarbon liquid in the formation and the displacement fluid to be used for displacing the hydrocarbon fluid. The solubility parameter of the hydrocarbon liquid can be determined by a variety methods including, but not limited to, (1) using the hydrocarbon liquid's energy of vaporization, DELTA Evap, and its molar volume, V, (2) using the volume-fraction-weighted average of the solubility parameter values for model compounds representing components of the hydrocarbon liquid, or (3) using the hydrocarbon liquid's average molecular weight and the temperature of the subterranean formation. The solubility parameter of the and a constant, rho r(liq) for a displacement fluid that is a pure compound, or (2) using the volume-fraction-weighted average of the solubility parameter values for each component of the displacement fluid. Residual oil saturation for a secondary displacement fluid also can be determined by a number of methods including, but not limited to, (1) using the displacement fluid's critical pressure, Pc, ratio of density to critical density, rho r, gasflood, Sorg, may also be predetermined using a substantially similar procedure.
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