Monitoring PVT properties derivatives ensures physically sound tuned EOS behaviour over the entire operating conditions rangeMonitoring PVT properties derivatives ensures physically sound tuned EOS behaviour over the entire operating conditions range Πλήρης Δημοσίευση σε Συνέδριο Conference Full Paper 2015-11-072005enIn this work, a method is proposed for guiding the Equation of State (EoS) tuning procedure against a set of laboratory measurements such as that a physically sound behaviour of the model can be produced throughout the operating compositions and conditions range. The derivatives of each individual EoS PVT prediction with respect to each of the input parameters are directly evaluated and subsequently utilised for verifying the behavior of the model throughout its applicability range. Thermodynamically sound profiles of the model derivatives which should be respected during tuning are also provided. By applying the Taylor expansion method, we demonstrate how typical EoS tunings can lead to significant prediction errors while moving along the multidimensional surface as conditions and composition vary during production.http://creativecommons.org/licenses/by/4.0/SPE Europec/EAGE Annual Conference Gaganis Vasileios Γαγανης Βασιλειος Varotsis Nikolaos Βαροτσης Νικολαος Nighswander, John Allan, 1963- Birkett Graham Paterson Society of Petroleum Engineers Equation of state equations of state equation of state