Estimating Hydraulic Conductivity of Heterogeneous Aquifers by Multi-Frequency Pumping Tests
You are cordially invited to attend this seminar
Monday, October 11th, 14:00 Room 206, Wolfson Mechanical Engineering Building
by David Guy
Under the supervision of Dr. Avinoam Rabinovich
Pumping tests are a common tool used in order to characterize an aquifer. In a typical test, water is extracted from the aquifer by a pumping well and drawdown (the change in water level) is measured along the field at observation wells. The aim of these tests is to estimate the hydraulic properties of the aquifer, mainly the hydraulic conductivity and the specific storage for use in models pertaining to various applications such as groundwater management and aquifer contaminant treatment.
An alternative to the conventional pumping test is the periodic or oscillatory test consisting of continuous injection and extraction of water in a harmonic fashion, creating a sinusoidal pressure signal.
A single frequency source of this type yields a single estimated property value, i.e., an equivalent conductivity (keq) that is associated with a homogeneous aquifer.
We suggest an extended method involving a multi-frequency source. Now we are able to associate an equivalent value to each frequency in the system. In case the aquifer is truly homogenous all values would be the same.
We investigate the case of a heterogeneous field and the frequency effect on keq.
We present two synthetic heterogeneous aquifers and their keq values associated with various frequencies. Our goal is to characterize the frequency dependence of keq in a numerical experiment to follow up on theoretical and field experiment literature which has previously observed an increase in keq as frequency of pumping is increased.
Our results show that keq has very small variations with changing pumping frequency and no specific trend is observed.
This could indicate that the phenomenon is minor and that the variations are on the same order of magnitude as the numerical errors.
https://us02web.zoom.us/j/82108132163?pwd=Z2h4UzNzUS9mbXplT0lMU1pZenFEQT09
