A common problem encountered in the management of oil reservoirs is excessive water production. Intelligent well technology is a potential solution provided we have a good understanding of the streaming potential coupling coefficient to interpret the signals. This book presents some review of various down-hole monitoring techniques, theory of spontaneous potential, and previous electrokinetic potential measurements conducted in both single phase and multi-phase systems. A detailed description of the methodology for the single-phase experiments adopted in this work is given, before the results...