A strategy for real-time automated analysis of pump tests

A computer-automated well test data acquisition system has been developed at Clemson University to support ground water-related educational and research activities at and near the Westinghouse Savannah River Site in Aiken, SC. The system includes high resolution borehole pressure transducers, a barometric pressure transducer, a digital flow meter, a frequency counter and voltmeter to process electronic signal from the instruments, disk drives to store the data, and a computer to provide real-time graphical display and analysis of the pump test data. Pressure drawdown and pumping flowrate measurements can be made as often as every second. To complement and increase the efficiency of this equipment, real-time automated analysis of drawdown data is being incorporated into the existing data acquisition capabilities of the system. The strategy for such an expert system includes: user controlled transfer of data from the data acquisition system to the expert system, recognition of data exhibiting wellbore storage effects, and implementation of an appropriate analysis method. The strategy also includes automated selection of an appropriate hydrological model or models by identifying characteristic signatures of the semi-log, log-log, and pressure derivative curves. Various hydrological models such as a confined and an unconfined infinite homogeneous model, a bounded model, andmore » a double porosity model will be employed. Analysis methods include the semi-log straight line curve method, Theis curve matching, and variable flowrate curve matching. The expert system is required to select a hydrological model and an analysis method and to test its decisions using statistical evaluation of the best fit curve match. The system may then compare its findings with those found using other models and analysis methods.« less