This paper describes a computer-aided interpretation approach that can be used to analyze the early time data of a transient test with wellbore storage and skin effects. Pressure derivative, pressure response and pressure cumulative are used to rearrange the convolution integrals into a linear relation of three variables. The coefficients of this relation are related to the model parameters of reservoir properties, wellbore storage constant and skin factor. A linear multiple regression is performed for these variables to obtain the optimal values for the model parameters. Once the model parameters are known, the calculation of pressure change can be performed for each flow regime assumed. The statistical and graphic analyses will be used to check the results, as well as the accuracy, of each flow regime assumed. This approach is simple. However, it requires that the reservoir response function does not change and the model parameters are constant during the analyzed period.

The advantages of this computer-aided interpretation approach are that the early time data can be analyzed numerically and the approach can be applied for any type of flow regime; i.e, radial, linear, bilinear and spherical flow.

A real data example is used to demonstrate the application of the proposed approach.

Keywords:
wellbore storage, flow regime, reservoir, sandface flowrate, pressure derivative, coefficient, pressure cumulative, radial flow, spe 18880, upstream oil & gas
Subjects:
Hydraulic Fracturing, Well & Reservoir Surveillance and Monitoring, Reservoir Characterization, Formation Evaluation & Management, Pressure transient analysis, Drillstem/well testing
Copyright 1989, Society of Petroleum Engineers
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