Resman’s Intelligent Tracer technology accurately quantifies zonal-inflow contribution and detects the location of water breakthrough. Applications include quantification of oil inflow contribution, water-breakthrough monitoring, and inflow-assurance monitoring. The information obtained with Resman Intelligent Tracer technology provides the equivalent of a production log but without the risk and cost of well intervention. No cables, connections, intervention, or major changes to completion design are needed. The oil-targeted Intelligent Tracers can achieve up to 5 years of life, while the water-targeted Intelligent Tracers can have longer lifespans because they are dormant until activated by contact with water. Resman’s chemicals are used in extremely low concentrations (down to parts per trillion) and are compatible for water discharge. No radiation is used. The Intelligent Tracer technology can be formed into a variety of shapes to allow it to be integrated into a wide range of completion designs. The Intelligent Tracer systems are designed to remain dormant until contacted by the target fluid. When contacted by the target fluid, tracer molecules are released in very small quantities. This release is independent of flow conditions and happens at a laboratory-designed rate. Resman chemists have developed more than 50 uniquely identifiable chemical signatures for oil and another 50 for water.