On the Loss of Injectant and Apparent Dispersivity in Single-Well Push-Pull Tests Influenced by Natural Drift

In a previous article, a semi-analytical stream-line based model was developed for single-well push-pull tests in stratified reservoirs subject to natural drift. Based on that model, this article gives the theoretical maximum injection phase duration giving conservative injectant production, in a single-layer reservoir with natural drift. In addition, an analytical expression for the single-layer apparent dispersivity due to natural drift is given. Finally, it is shown how the large-scale apparent dispersivities observed in experimental data from a stratified aquifer may be predicted by constructing a production profile using the estimated single-layer apparent dispersivities.