A tracer release system releases tracer into a well. The tracer release system includes at least one tracer release apparatus having at least one tracer source reservoir comprising at least one tracer, at least one injection port in fluid communication with the well and at least one controllable valve located between the at least one tracer source reservoir and the at least one injection port. The at least one controllable valve is configured to control an even release of the at least one tracer into the well for a desired duration and/or frequency.