digilib@itb.ac.id +62 812 2508 8800

”X” Oilfield in Sudan has a shallow reservoir affected by significant boundary and bottom water with excellent characteristics and high crude oil viscosity. The field is classified as heavy oil. The reservoir of “X” oilfield is described by an average temperature and pressure system at 550 m depth. The average pressure is 576 Psi, and the average temperature is 43.9 °C. “X” Oilfield is constructed from three layers, F1, F2, and F3, it has a conventional heavy oil in both F1 and F2 two layers, and the F2 reservoir has a relatively good quality with porosity ranging from 17 to 40%, permeability ranging from 100 to 11000 mD and viscosity of about 840 cP. In this research, through a comprehensive analysis of currently producing wells performance, perforation intervals, steam parameters optimization using two approaches (Deterministic and Stochastic), CO2 temperature sensitivity analysis, and CSS optimization, will analyze the combination of continuous steam flooding with CO2-assisted steam flooding and cyclic steam stimulation in pilot test SCTR. Based on this study, thermal simulation results using CMG-STARS and CMOST AI simulation software, applying multiple ways of thermal EOR in the Pilot test SCTR, and using Oil Recovery Factor (RF) as the objective function, we can conclude: Although CO2-assisted steam flooding may reduce the water cut, its effect on the oil recovery factor is only 44.56percent after B.T when the water cut reached 95 percent. Best case of CSS combined steam flooding is applying steam flooding after 5 cycles from the case of 3 cyclic months period. Continuous steam flooding has the best oil recovery from these methods. The optimum steam parameters for this SCTR are the rate of steam injection 300 m3/D, the steam temperature of 250 oC, and steam quality of 0.9 with a maximum oil recovery factor of 45.95 % and the highest cumulative oil of 1,4 ?106 m3.