Reservoir engineering is a crucial discipline in the oil and gas industry, focused on optimizing the recovery of hydrocarbons from subsurface reservoirs. It involves the application of engineering principles and advanced technologies to assess reservoir behavior, estimate reserves, and design efficient production strategies. Reservoir engineers utilize data from well tests, seismic surveys, and production history to model the reservoir's properties, including porosity, permeability, and fluid saturations. Reservoir simulation, a key tool in reservoir engineering, employs numerical models to predict reservoir performance under various operating conditions. Enhanced oil recovery (EOR) techniques, such as waterflooding and gas injection, fall under the purview of reservoir engineering to maximize hydrocarbon extraction. Material balance calculations and decline curve analysis assist in estimating reserves and forecasting production rates. Pressure transient analysis, well testing, and surveillance programs are employed to monitor reservoir performance and optimize well interventions. Reservoir engineers collaborate with geoscientists, drilling engineers, and production teams to develop comprehensive field development plans. As the industry navigates challenging reservoir conditions and strives for sustainable resource recovery, reservoir engineering plays a pivotal role in maximizing the economic and environmental efficiency of oil and gas production. Advances in data analytics, artificial intelligence, and modeling techniques contribute to the continual evolution of reservoir engineering practices.