The self-potential (SP) method is a passive geophysical method based on the monitoring of electrical currents naturally occuring in the subsurface. It is sensitive to fluid flows, to the existence of concentration or redox potential gradients, and to temperature gradients. As it is low-cost, easily implemented in the field and also allowing the field to be densely covered in space and time, it is of great interest for hydrogeophysical field studies. However, the signals are weak, and often different sources are acting together.