Effect of Viscosity Ratio on the Recovery of Fresh Water Stored in Saline Aquifers.

摘要

Differences in viscosity between injected and displaced fluids will always result in a lower recovery efficiency during underground water storage in aquifers than would have been realized had the viscosities been equal. This result arises from (1) increased dispersion and (2) viscous fingering (gross frontal irregularities). Experimental studies involving injection and subsequent production from single wells in two physical flow systems (miniaquifers) suggest the following conclusions: (1) The recovery efficiency is a maximum where the fluid viscosities are equal; (2) from an engineering point of view,the recovery efficiency is approximately the same for a fixed viscosity difference irrespective of whether injected or native water is the more viscous; (3) a computational procedure previously developed for a viscosity of unity is applicable for a non-unity viscosity ratio provided an effective dispersivity is used which has been obtained from an injection/production well test;and (4) dispersivity coefficients obtained from the production profile of an observation well rather than the injection well represent highly unrealistic values and if used in the computational procedure will yield false values of recovery efficiency.