New Approach for Pulse Test Analysis

Abstract

Abstract New concepts are introduced to define time lag and response amplitude. The points of extreme pressure values (maxima and minima) are used to define the time lag and pressure response amplitude. The points of maxima and minima are found by equating the pressure derivative to zero. This results in a more accurate solution of the governing equations. The developed method is based on well-defined and easily locatable points, making the method amenable to automatic analysis by computer procedures. It eliminates the need for manually plotting of parallel tangents to the pressure profiles which is subjective, less accurate and does not amend itself to automatic processing. The solution is used to construct correlation charts for relative time lag and dimensionless pressure response amplitude vs. the dimensionless cycle time for different values of the pulse ratio. The correlation charts will be used to analyze results of pulse testing to obtain interwell reservoir properties, namely transmissibility kh/μ and storativity hϕct. Simulation examples are generated to validate the developed procedure. Results indicate the robustness of the developed method and its superiority over the conventional pulse test analysis method. The developed correlations show that the relative time lad decreases linearly with the dimensionless cycle time on a log-log plot. Results also indicate that the relative time lag and dimensionless pressure response amplitude decrease with pulse ratio for odd pulses and increase for even pulses.