A New Method for Interpreting Well Test Data in Fractured Reservoirs: a Dual Porosity Model

In this study, a new method is developed to estimate the fracture parameters in fractured reservoirs. This method is used to interpret incomplete well test data and is applicable to both drawdown and buildup tests. Using this method, the value of λ/ω ratio can be estimated for the drawdown test when the first straight line and an early transition zone are solely observed in the test data. Hence, there is no need to observe the inflection point in the semi-log plot of the pressure data. For buildup test, however, the technique can be combined with previously published approaches to estimate separate values of λ and ω. The main assumption behind the new technique is employing the dual porosity model with pseudo-steady state interporosity flow to obtain the final solution; the final equation is achieved by approximating the pressure derivative data using the Taylor series. The permeability of the rock matrix can be estimated through new developed technique provided that sufficient fluid and rock data are available. For validation purposes, three different well test cases (two drawdown and one buildup) have been simulated using the Pansystem software. Moreover, a field case, adopted from the open literature, is used to test the accuracy of the developed technique over actual field data. The results revealed that the value of λ/ω estimated through the new technique has an insignificant difference with the input λ/ω values for simulation purposes.