T This study aims to evaluate the reservoir drive mechanism of field man using the material balance method and the ganesh c. thakur analytical approach as a comparative analysis. the reservoir drive mechanism represents the natural energy that drives hydrocarbon fluids from the reservoir toward production wells. a thorough understanding of the dominant drive mechanism is critical for predicting reservoir performance, estimating hydrocarbon reserves, and designing an optimal field development strategy.the evaluation of the reservoir drive mechanism in this study was conducted through two approaches, namely qualitative and quantitative analysis. the qualitative analysis was performed by observing historical production data trends, such as changes in the gas-oil ratio (gor), water cut (wc), and the relationship between reservoir pressure and cumulative production. meanwhile, the quantitative analysis was carried out through a series of systematic and interrelated stages.the first stage is pvt matching, which involves fitting laboratory pvt data with empirical correlations using mbal software to ensure the accuracy of reservoir fluid parameters such as bo, rs, bg, and oil viscosity as the primary inputs for material balance calculations. the second stage is dynamic reserve estimation using the material balance equation (mbe) through two graphical methods: the campbell plot (plot of f/eo versus f) to detect the presence or absence of natural water influx and to provide an early identification of the dominant drive mechanism, and the havlena-odeh plot (plot of f/eo versus eg/eo or we/eo) to quantitatively estimate the original oil in place (ooip) from the slope and intercept of the resulting straight line. the dynamic ooip values obtained from both graphical methods are subsequently compared against the static reserves derived from volumetric calculations based on geological and petrophysical data, in order to evaluate the consistency and validity of reserve estimations across methods. the third stage involves the calculation and plotting of the drive index using the havlena-odeh framework to quantify the relative contribution of each drive mechanism, including solution gas drive, gas-cap drive, water drive, gravity drainage, and compaction drive, to the total reservoir energy. the quantitative drive index results are then compared with the analytical ganesh c. thakur approach, which reconstructs drive mechanism curves based on historical production characteristics, serving as a cross-validation against the material balance results.the evaluation results are expected to provide a comprehensive picture of the dominant drive mechanism in field man, as well as the relative contribution of each reservoir energy source. the comparison between dynamic and static reserves is expected to confirm the reliability of the geological data and the quality of the reservoir model used. therefore, this study is expected to serve as a foundation for understanding reservoir energy characteristics, improving oil recovery efficiency, and supporting the planning of production optimization strategies and field development in the future.