Determination of Initial Gas in Place and Active Water Drive in Single-Phase Gas Reservoirs Using the Material Balance Method

Abstract

Oil and natural gas remain the world's primary energy resources and continue to play a fundamental role in the global economy. Consequently, the effective management and optimal exploitation of subsurface hydrocarbon reservoirs to maximize hydrocarbon recovery represent major challenges in petroleum engineering and related scientific disciplines. One of the fundamental objectives of reservoir engineering is the estimation of hydrocarbon reserves throughout both the early production stage and the depletion phase of a reservoir, as well as the identification of the natural reservoir drive mechanisms responsible for fluid flow from the reservoir formation to the production wells. These evaluations are essential for the proper characterization, management, and efficient development of oil and gas reservoirs. The present study demonstrates the application of the Material Balance Method to single-phase gas reservoirs for the determination of the Initial Gas in Place and the identification of the presence of an active water-drive mechanism. The proposed methodology integrates historical production data with the physical properties of reservoir gas over a specified production period. The obtained results illustrate the effectiveness of material balance analysis as a practical and reliable reservoir engineering tool for reservoir characterization, reserve estimation, and the evaluation of reservoir drive mechanisms, thereby providing valuable support for reservoir management and future field development planning.