Transmissivity identification through multi-directional aquifer stimulation

This paper presents a geostatistical approach to multi-directional aquifer stimulation in order to better identify the transmissivity ®eld. Hydraulic head measurements, taken at a few locations but under a number of different steady-state ̄ow conditions, are used to estimate the transmissivity. Well installation is generally the most costly aspect of obtaining hydraulic head measurements. Therefore, it is advantageous to obtain as many informative measurements from each sampling location as possible. This can be achieved by hydraulically stimulating the aquifer through pumping, in order to set-up a variety of ̄ow conditions. We illustrate the method by applying it to a synthetic aquifer. The simulations provide evidence that a few sampling locations may provide enough information to estimate the transmissivity ®eld. Furthermore, the innovation of, or new information provided by, each measurement can be examined by looking at the corresponding spline and sensitivity matrix. Estimates from multi-directional stimulation are found to be clearly superior to estimates using data taken under one ̄ow condition. We describe the geostatistical methodology for using data from multi-directional simulations and address computational issues.