A method of estimating influx profile for well fluids (oil, gas, or water) to petroleum well with influx locations to a production flow, including: arranging tracer sources with tracer materials in levels of the well, arranged downstream and exposed to the fluids in the influx zones, each of the tracer sources having even release rate to the well fluid, inducing a transient in the production rate of the entire production flow by shutting in by a valve topside, changing the local exposure times of the tracer sources to the fluid, collecting samples, downstream at known sampling times, analyzing the samples for concentration and type of tracer material from the possible sources, based on the concentrations and their sampling sequence and the well geometry, calculating influx volumes from flow models.