Abstract

Pulse testing is an excellent technique used to determine the value and direction of reservoir permeability and other important parameters. When reservoir permeability is very low, however, the testing time that is designed by the conventional pulse testing theory may be more than two months. Its cause is that the pressure in many oil wells is still increasing when they have been shut in for more than thirty days. In view of the fact mentioned above, the authors developed a new theory and give interpretation method of pulse testing. The theory and method are suitable for responding well in buildup. In contrast, the conventional pulse testing theory is based on the fact that the pressure in the responding well must be stable. Consequently, it demands a much longer testing time than the new theory by the authors.

In the paper, a mathematical model is first established to describe the new pulse testing theory. with the wellbore storage coefficients and skin factors considered both in the responding well and in the pulsing well. Then, an exact solution to the mathematical model is derived in Laplace Space. According to non-linear regression analysis technique, the characteristic parameters of a reservoir are obtained by solving the objective function that is established by observed and calculated pressure. The theory has been applied to Shanshan reservoir pulse testing design and analysis for several times, the interpretation results are satisfactory, and the testing time is only 12 to 18 days in such reservoirs with low permeability as Shanshan. The actual application has shown that the new pulse testing theory and analysis method are practical. They can shorten the testing time, especially for low permeability reservoirs.

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