continuous pressure derivatives from well-test data Algorithm for determining smooth

An algorithm is presented for determining smooth, continuous pressure-derivative functions from measured well-test data. The algorithm fits a spline function to a set of measured pressure data; the first and second derivatives of the resulting spline function are calculated analytically and can be used for type-curve matching. The algorithm allows the user to impose shape constraints on the spline function and its derivatives to help evaluate whether an appropriate well-test interpretation model has been chosen. The performance of the algorithm is illustrated with two examples.

Algorithm for determining smooth, continuous pressure derivatives from well-test data Academic Article