Report on the Evaluation of Ugua J2 and J3 Reservoir Performance

Abstract

Globally, there are different techniques applied in the industry such as analog, volumetric, decline curve, material balance and simulation methods to estimate hydrocarbon reserves which depends upon the volume and quality of available data with some levels of uncertainties. The analogy method is applied by comparing factors for the current fields or wells while the volumetric method implies the determination of the extent of the reservoir, pore volume of the reservoir rock and the content of fluid within the reservoir pore volume when production and pressure data from field become available, decline curve analysis and material balance calculations become the predominant methods of calculating reserves since the hydrocarbon reserve estimates is a continuous process for a field that is producing. This study presents a report on the material analysis of Ugua J2 and J3 reservoirs with MBAL prior to the field’s dynamic reservoir simulation. The available data were validated and the analytical plot of pressure and production data indicated that J2 and J3 reservoirs are communicating. Hence multi-tank material balance analysis approach linked with transmissibility was adopted to model the reservoirs. The Hurst-Van Everdingen radial aquifer model was selected as the most likely case. The oil initially in place value obtained for J2 and J3 are 125.006 and 80.689 MMstb.