Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
EFFECT OF IMMISCIBLE LIQUID CONTAMINANTS ON P-WAVE TRANSMISSION THROUGH NATURAL AQUIFER SAMPLES
 

Summary: EFFECT OF IMMISCIBLE LIQUID CONTAMINANTS ON P-WAVE
TRANSMISSION THROUGH NATURAL AQUIFER SAMPLES
Jil T. Geller, Earth Sciences Div., Lawrence Berkeley National Lab., Berkeley, CA
Jonathan B. Ajo-Franklin, Dept. of Geophysics, Stanford University, Stanford, CA
Ernest L. Majer, Earth Sciences Div., Lawrence Berkeley National Lab., Berkeley, CA
Abstract
We performed core-scale laboratory experiments to examine the effect of non-aqueous phase
liquid (NAPL) contaminants on P-wave velocity and attenuation in heterogeneous media. This work is
part of a larger project to develop crosswell seismic methods for minimally invasive NAPL detection.
The test site is the former DOE Pinellas Plant in Florida, which has known NAPL contamination in the
surficial aquifer. Field measurements revealed a zone of anomalously high seismic attenuation, which
may be due to lithology and/or contaminants (NAPL or gas phase). Intact core was obtained from the
field site, and P-wave transmission was measured by the pulse-transmission technique with a 500 kHz
transducer. Two types of samples were tested: a clean fine sand from the upper portion of the surficial
aquifer, and clayey-silty sand with shell fragments and phosphate nodules from the lower portion. Either
NAPL trichloroethene or toluene was injected into the initially water-saturated sample. Maximum
NAPL saturations ranged from 30 to 50% of the pore space. P-wave velocity varied by approximately
4% among the water-saturated samples, while velocities decreased by 5 to 9% in samples at maximum
NAPL saturation compared to water-saturated conditions. The clay and silt fraction as well as the larger
scatterers in the clayey-silty sands apparently caused greater P-wave attenuation compared to the clean

  

Source: Ajo-Franklin, Jonathan - Earth Sciences Division, Lawrence Berkeley National Laboratory

 

Collections: Geosciences