Summary
It is well known that wellbore storage and phase redistribution have a direct influence over well-testing data, mainly on those recorded at early times of the test. After this early time period, such influence disappears, and the pressure response is dominated by the reservoir and the skin zone properties. However, sometimes the effects of wellbore dynamics last long enough to completely disguise the reservoir response. This situation frequently constrains the use of such analysis procedures as type-curve matching, especially if the test did not last long enough to reach radial-flow conditions. Some tests are uninterpretable because of the duration of these wellbore effects.
By means of two classical models related to well test affected by changing wellbore storage, this work introduces a new method of analysis for those tests with insufficient duration to reach radial-flow conditions. The methodology proposed in this work is illustrated with synthetic examples and a field case. For some synthetic cases the type-curve-matching procedure may yield completely erroneous values for the parameters, whereas, with the suggested method, reasonable estimates are obtained.
