A production pipe arrangement for a producing petroleum well with at least one of the well fluids (oil, gas, or water) with influx fluids two or more influx zones or influx locations to a production flow in a central production pipe in said well, with tracer sources with distinct tracer materials in known levels of the well, one or more separate delay chambers arranged as a completion component in said pipe, the delay chambers provided with said one or more of the tracers sources arranged in an annular space formed between the completion pipe and a borehole wall, with at least one of said tracer sources arranged exposed to the fluids in at least one of said influx zones, the delay chambers having one or more apertures to the fluid flow in said central pipe.