Tracer release method for monitoring fluid flow in a well

The invention relates to a tracer release method for monitoring the fluid flowrate in a downhole well conduit. Such a method is known from European patent application No. 0816631. A tracer release method for monitoring fluid flow in a well utilizes a deformable container having a liquid tracer material which container has an outlet which debouches into the neck portion of a venturi in a well conduit. The container has a wall which is at least partly exposed to the fluid pressure at the relatively wide in- or outlet of the venturi, so that an amount of tracer is injected continuously or discontinuously into the well effluents which is proportional to the pressure difference p across the venturi, which pressure difference p is indicative of the fluid density and squared fluid velocity .