Air sparging tracer test to investigate the flow path

The paper presents a useful method for investigating the flow path of the i njected air, estimating the radius of influence, and assisting the design o f well spacing of sparging wells. The method applies both tracer and modeli ng approach. A field test using helium as a tracer was conducted on an air sparging pilot. A 3-dimensional, 3-phase compositional model was utilized t o simulate the air sparging process at the pilot. The model was first calib rated with the tracer concentrations observed in the field test at various locations between the air sparging well and the soil vapor extraction well. The calibrated model was then used to predict the flow path of the injecte d air and to simulate the water saturation distributions in the aquifer. Th e steady-state water saturation distributions was found useful for estimati ng the radius of influence of air sparging and for designing the well spaci ng of sparging well.