An analytical model for injectivity tests in multilayered reservoir with formation crossflow

Injectivity tests involve injecting fluid through wells into an oil reservoir to gather information about its parameters. This knowledge can be valuable for improving oil production. As such, several studies on injectivity tests in multilayered reservoirs have been conducted. Typically, these studies focus only on commingled systems, which are layers separated by impermeable barriers. The present work developed an analytical model in the Laplace space for multilayered reservoirs under injectivity tests, considering formation crossflow across all layers. The accuracy of the proposed solution was verified by comparing it with a finite difference flow simulator. The results from the analytical model and numerical data are consistently similar. Additionally, the analytical solution’s data is used to estimate the reservoir’s equivalent permeability, which yields satisfactory accuracy for all tested cases.