Full-Field Simulation and Optimization Study of Mature IWAG Injection in a Heavy Oil Carbonate Reservoir

Abstract Bati Kozluca Field is a heavy oil carbonate reservoir discovered in 1985; it is located in the South East of Turkey, close to Syria border. The reservoir began primary production in 1985, developed with 41 wells producing 12.6 API oil. Main constraints for oil recovery are the low aquifer support, low solution gas oil ratio and high oil viscosity which is 480 cp at reservoir conditions. In order to increase 5% recovery, full field continuous immiscible CO2 injection had been implemented from 2003 to 2007 and full field IWAG injection had been implemented from 2007 to 2012. These projects increased the oil recovery from 5% to 6.7% and increased the daily oil production two times. In 2012, it was decided to re-develop the field to increase the 6.7% recovery. This paper first gives the results of the CO2 and IWAG applications in the Batı Kozluca Heavy Oil Field and then describes the field-wide simulation study conducted to predict the future reservoir performance of the black oil simulation model under various operating and development strategies. First, available data is screened and quality of the data is evaluated; then, dynamic model is built. The model has been successfully history matched with 27 years of production, injection, saturation and pressure history on both the field and the well scale. The history matched model is used to decide the methodology and to determine the infill well locations, injection pattern and injection schemes to increase the oil recovery. Simulation results show that recovery can be increased from 6.7% to 9% with the current injection pattern and without any investment by continuing the project with the optimized injection parameters. However, injection pattern needs to be modified to increase the volumetric sweep efficiency and oil recovery.