The use of multilateral wells in the oil industry has increased rapidly during the last decade. The main reason for this upsurge is that these wells provide large contact areas with the reservoir and therefore better recovery performance is achieved. In addition, the availability of new technologies in recent years has substantially reduced the cost of drilling these wells. In fact, in many areas of the world, drilling multilateral wells is becoming the norm when deciding to drill new wells. Furthermore, the continuous growth in the world oil demand stimulates the oil producers to develop all kind of resources including heavy oil reserves. The significant heavy oil accumulations already existed in the world has led to a greater emphasis on their development using thermal EOR methods. This study investigates numerically the performance of using multilateral well configurations in recovering heavy oil from heterogeneous reservoirs using hot water flooding. In order to cover a wide range of heterogeneity, a series of reservoir permeability maps, each with different permeability structures and variations, were generated stochastically. In each of these heavy oil reservoirs, extensive three-dimensional, fine-mesh simulation runs were performed using different configurations of multilateral wells. The oil recovery performance obtained by hot water flooding was compared to that obtained by conventional water flooding in all these reservoirs. The objective was to determine the functional relationships between the oil recovery performance and several design parameters including: (1) degree of heterogeneity (2) well configurations, and (3) viscosity ratio. Results show that these parameters play important roles in the displacement behavior of heavy oil using multilateral wells, with reservoir heterogeneity having a more significant effect. The study suggests that there exist critical values of these parameters under which hot water floods can be more effective than conventional water floods. The paper will present these conditions in detail and situation where the performance of hot water floods can be ineffective.

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