Validation of transient time method to calibrate oil flow meters in closed conduits using ¹²³I as the radiotracer

To assure the credibility of commodity transfer operations in the oil and gas industry, calibrated flow meters are used to quantify the movement of fluids in the pipelines. The purpose of this paper is to validate the transient time method (TTM) to calibrate oil flow meters installed in restricted areas, using the ¹²³I-labelled oil as a radiotracer. Traditionally, as proposed by the standard ISO 2975-7:1977 [1] for experiments in an aqueous medium, the TTM is employed by positioning two detectors at separate locations. However, in industrial plants, it is not always possible to install detectors at the distances recommended by the ISO 2975-7. The method proposed in this paper uses four scintillator detectors separated one from each other by 0.30 m and three injections containing 5.0 ml of ¹²³I-labelled oil. The experiments were carried out in an oil flow rig with a turbulent flow profile. The results have reached an uncertainty which is lower than 1.0%.