Abstract
Self-potential (SP) monitoring was carried out at Mataloko, Flores Island, Nusa Tenggara, Indonesia to detect electric potential changes at the reservoir caused by well operations. Surface SP distribution was monitored around the well during flow tests. To solve the problem about a base point of SP, a concept of relative SP was introduced assuming that the average SP among the monitoring points is always zero. As a result, a clear change of the relative SP corresponding to the reservoir condition was observed. Thus relative SP monitoring can be applied to grasp the extent of a reservoir and the change of its hydrological conditions.
