How to Monitor Possible Side Effects of Enhanced Oil Recovery Process

To extract all the oil from a well, petroleum engineers pump hot reactive chemicals into the well. These Enhanced Oil Recovery (EOR) processes need to be thoroughly monitored, since the injected fluids can seep out of the production oil wells and, if unchecked, eventually pollute sources of drinking water. There is a need to measure the corresponding effects. One way to measure these underground effects is by observing seismic waves resulting from hot fluids-induced fracturing. Seismic waves generated by this fracturing are, however, weak in comparison with the background noise. Thus, the accuracy with which we can locate the spreading liquids based on these weak signals is low. Hence, we get only an approximate understanding of how those liquid propagate in the reservoir. To get a more accurate picture of the propagation of these fluids, we propose to use active seismic analysis: namely, we propose to generate strong seismic waves and use a large-N array of sensors to observe their propagation.