Permanent reservoir monitoring using passive electrical measurements

Downhole monitoring of the spontaneous electrical potential (SP), using electrodes permanently installed on production or injection wells, is a promising new technology for imaging waterfronts and monitoring water movement in a hydrocarbon reservoir, in real time, during production. The method is distinct from other electrical methods because these require an active source and are limited in their depth of investigation. The SP signal is generated by moving water, salinity and temperature fronts in the reservoir, allowing a (much) greater depth of investigation and requiring less sophisticated downhole hardware. This presentation will review the results of numerical modelling and laboratory experimentation that suggests waterfronts can be monitored while they are several tens to hundreds of metres away from an instrumented well. Other potential applications, and the next steps required to implement the method as a viable technology, are also discussed.