PVTSim is a versatile software product for simulating fluid properties and PVT experiments, which absorbed all the knowledge and experience of Calsep experts. PVTSim is the only product that the company develops. And the company success and stability entirely depends on this product success. It is not surprising that today it is the most advanced and functional product of this class on the market and, moreover, it is constantly improving. There are several options for equipping PVTsim by different modules for a wide range of tasks. In particular, PVTsim has interfaces to all commercially available hydrodynamic reservoir simulators: CMG, Eclipse, MORE, VIP, etc. – that allows for not only to create and configure fluid models, but also to transfer them into any existing simulator that makes PVTsim a versatile tool.