Compositional simulation becomes more and more important in the petroleum industry. It provides a more accurate description of the reservoir fluid compared to the black-oil model which is insufficiently accurate for EOR (Enhanced Oil Recovery) processes. The general objective of this thesis is to contribute to the development of a knowledge repository which is created for an operating petroleum company. Therefore practical applications, tutorials on fluid characterization as well as on compositional simulation were created. An analysis was done on the results obtained by the compositional simulators SURE and ECLIPSE 300. The results obtained by SURE showed discrepancies compared to those of ECLIPSE 300. Therefore an analysis on the code, which is implemented in SURE, was done and in this thesis recommendations are presented to update the code in SURE. Tutorials were developed to show the workflow of fluid characterization in PVTi and furthermore different cases were constructed to demonstrate features which are available in ECLIPSE 300. Emphasis was put on the simulation of miscible processes in ECLIPSE 300. For this purpose the workflow for simulating slimtube experiments is presented and practically demonstrated. This includes the determination of the Minimum Miscibility Pressure.