Analysis of buildup tests with short producing time

Pressure build-up data with a short producing time is often difficult to analyze. Although the semi-log method known as Horner method can be used, the drawdown type curve should not. Thus, trying to determine if the semi-log plot actually includes the correct straight line is difficult. In this paper, a new log-log graph specially designed for a pressure build-up test with short producing time is suggested. This graph allows the user to easily determine the type of flow regime (linear, bi-linear, or radial). Consequently, it can be used to detect the presence of the correct semi-log straight line. The new graph can also be used to calculate the formation permeability or fracture conductivity in a fashion similar to the semi-log method. The paper briefly presents the analytical models used in developing the new technique. The models consider both wellbore storage and skin effect. Two examples are presented and discussed. The first example is computer-simulated while the second is a field example. Use of the new technique to analyze a buildup test with short producing time is presented and briefly compared to the existing techniques.