MBAL’s progressive menu options lead the engineer logically through the history matching process, which is performed graphically using industry standard techniques (e.g. Cole, Campbell, P/Z plots) and allows the identification of drive mechanisms in place, and whether the measured data entered is to be trusted. Having used the analytical methods available in MBAL to history match the analytical model, a simulation is run of the history, and yields two valuable results: Firstly, by running the historical period in a simulation, the user can compare the production profiles predicted from the model and the data entered (a close match indicating a good history match). Secondly, by running the history as a prediction, MBAL will calculate all the historical production profiles, saturations and reservoir pressures in the historical period. This can be used to create custom relative permeability curves and calibrate these to the History matched model. The historical data can be entered on a tank basis, or in a well by well basis, in the latter context the Relative Permeability curves can be generated for the draining area of each well using the approach described above. It is this innovative capability that allows the analytical model to approach the response of reality and is a departure from classical literature based models.