Perspectives for Application of the WAG and SWAG Eor Techniques: a Case Study on the Pannonian Basin Oil Field, Serbia

Abstract

Summary The idea of this study is to investigate the perspectives for application the Water Alternating Gas (WAG) and Simultaneous Water Alternating Gas (SWAG) techniques as potential EOR methods in the “Sm” oil reservoir – part of an “X” field in the southeastern part of the Pannonian Basin, Republic of Serbia. Reservoir is a massive one, with a light to medium oil in place. Reservoir rocks are different clastic sediments (sandstones, alevrolites) and the cap rocks are clays and marls. Workflow of this study included: (1) literature overview, (2) screening for application of the WAG and SWAG EOR techniques on Serbian fields, (3) gathering and analysis of the reservoir data, (4) modelling fluids’ PVT properties, (5) petrophysical modelling of the reservoir rock properties, (6) preparation and initialization of the 3D compositional hydrodynamic model (in tNavigator 18.2) for the simulation of displacement processes and assessment of field development parameters. Study showed that the studied reservoir is suitable for application of the SWAG and WAG EOR techniques. This conclusion was based on the improvement of oil recovery and additional cumulative oil production. for the best EOR case (CO2 and saturated gas CGI and WAG), oil recovery increased from 25,1% up to 46,2%.