METHOD OF PROCESSING FORMATION PULSE TESTING DATA

A new method is presented for processing data of productive formation pulse testing, based on the use of specially modified pressure recovery functions, with the pressure measured in the observation well of the formation. The functions are constructed by subtracting from real pressure recovery functions the second highest members of the asymptotic series of an integral exponential function representing an exact analytical solution of the diffusivity equation describing the dynamics of pressure variation in the well during formation pulse testing. The performed analysis has shown that the Bourdet derivatives of pressure recovery functions modified by the suggested method are much faster in approaching horizontal asymptotes whose height is used to determine the formation parameters. This allows the use of a time-logarithmic part of the pressure recovery function, with the pressure measured in the formation observation wells, to process formation pulse testing data, which ensures an improvement in the accuracy and validity of determining its parameters. In processing real field pulse test data, modified pressure recovery functions should be constructed by an exhaustive method of searching multipliers before the second members of the asymptotic series with a view to identifying optimum values of these multipliers ensuring the fastest way for the Bourdet derivatives to approach a horizontal asymptote.

Author:  A. M. Svalov
Keywords:  formation, pulse testing, integral exponential function, Bourdet derivatives
Page:  614