Injectivity test is a conventional technique in reservoir engineering used for oil recovery and formation evaluation. Typically, water is injected to displace the existing oil by increasing the pressure in the pores.
In this test, the pressure response measurement provides valuable information about the reservoir parameters, including permeability data.

Therefore researchers aim to develop mathematical equations that could accurately model pressure response during these tests for reservoir management and maintenance prediction purposes.

This work introduces a new analytical solution for injectivity test analysis. The solution combines the pressure-pressure convolution technique with a two-zone radial model. It allows the evaluation of the injectivity test without precise flow rate data, as the pressure-pressure convolution exclusively uses the pressure data acquired at different positions in the reservoir.

The reservoir model comprises an injector well in the inner zone of the reservoir and an observation well in the outer zone for measuring pressure response.
The proposed solution was validated by comparing the analytical results with those obtained from a commercial simulator with finite differences