In the oil industry, estimating the presence of oil reserves is a key issue during the reservoir exploration, evaluation, and development stages and should be investigated because of the risks and inaccuracies that are considered inherent issues. Moreover, true and distinct hydrocarbon content can only be discerned upon field production or depletion. The challenge of estimating reserves is therefore a function of time and available data. In this study, Different Known modules with varying levels of analytical accuracy were utilized to establish the Initial Oil InPlace (STOIIP) of the Asmari reservoir in Fauqi Oilfield through analysis of production history from one well. The accuracy of the results obtained was examined and showed an acceptable level of reliability. Results from various models indicate that the most reliable estimate of OOIP is approximately 1.01MMMbbl for the Asmari reservoir using a multi-column model. Furthermore, by performing different analytical and numerical calculations on the Fauqi well production history, the uncertainty in the reservoir calculations of STOIIP can be reduced.