Abstract
Accurate predictions of fluid flow, mass transport, and reaction rates
critically impact the efficiency and reliability of subsurface
exploration and sustainable use of subsurface resources. Quantitative
dynamical sensing and imaging can play a pivotal role in the ability to
make such predictions. Geophysical thermoacoustic technology has the
potential to provide the aforementioned capabilities since it builds
upon the principle that electromagnetic and mechanical wave fields can
be coupled through a thermodynamic process. In this letter, we present
laboratory experiments featuring the efficacy of thermoacustic imaging
in the monitoring of preferential flow of water in porous media. Our
laboratory experimental equipment can be readily packaged in a form
factor that fits in a borehole, and the use of multiple acoustic
transducers—which can be combined with volumetric coding
techniques—has the potential to provide quasi-real-time imaging (0.5
Hertz video rate) of regions in close proximity (a few meters) of an
open field well.