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Abstract
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Recently new well test interpretation methods are developed in order to eliminate the wellbore storage effects. It is shown that the pressure response to constant rate production can be obtained from deconvolution of sandface flow rate and wellbore pressure data. The unit response function can be analyzed to indentify the type of reservoir system that is under testing and to estimate its parameters. These new methods require simultaneously measured sandface flow rate and wellbore pressure data. While accurate pressure measurements are commonplace, the measurement of sandface flow rates is rare, essentially nonexistent in practice.
This thesis addresses some methods for interpretation of oil and gas well test data distorted by wellbore storage effects. Using these techniques, we can deconvolve pressure and rate data from drawdown and buildup tests dominated by wellbore storage. Some of these methods have the advantage of deconvolving the pressure data without rate measurement. The two important methods that are applied in this study are an explicit deconvolution method and a modification of material balance deconvolution method. In cases with no rate measurements, we use a blind deconvolution method to restore the pressure response free of wellbore storage effects. Our techniques detect the afterflow/unloading rate function with explicit deconvolution of the observed pressure data. The presented techniques can unveil the early time behavior of a reservoir system masked by wellbore storage effects, and thus provide powerful tools to improve pressure transient test interpretation. Each method has been validated using both synthetic data and field cases and each method should be considered valid for practical applications.
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