<p>Dynamic reservoir characterization involves analyzing a reservoir’s behavior over time, particularly as fluids (like oil, gas, and water) are produced or injected. The main objective of the study is to assess the dynamic reservoir characteristics of the Haripur oil field, Sylhet, Bangladesh in synchronous and post production phases by applying streamline simulation technique. The field started production in 1987 and terminated in 1994 producing approximately 0.53 MMSTB of oil. In the current study, the dynamic behavior of the Haripur reservoir has been assessed based on some key performance indicators such as flow line concentration, oil flow rate, pressure and time of flight (TOF). The indicators were obtained by using Petrel 2009 software platform from production data gathered during the well’s peak and late production phases. Flow line concentrations which refer to the accumulation of streamlines within a specific region indicating variations in flow velocity and pressure, show a considerable connectedness among the flow paths between synchronous and post production periods. Oil flow rate is decreased significantly among the periods. The flow pressure has been decreased by 91.74% within synchronous and post production phases. On the other hand, the TOF and oil saturation have experienced only a minor variation that implies the presence of significant amount of oil in the reservoir till the present day. This study presents a novel application of streamline simulation to evaluate the dynamic reservoir characteristics of the Haripur oil field in Bangladesh, focusing on both synchronous and post-production phases—an approach rarely applied in regional reservoir analyses. By examining unique indicators such as flow line concentration, time of flight, and pressure decline, this research provides critical insights into remaining reservoir potential and connectivity that can inform future production and development strategies.</p>