Optimization of Toe-up SAGD Preheating in the Athabasca Oil Sands Reservoir

In the oil sands reservoir with continuous shale layers, steam-assisted gravity drainage (SAGD) well-pairs are located above the shale layers to improve performance.This may lead to a decrease in the net-pay zones, necessitating a well-pair that can secure these zones while avoiding the influence of shale layers.This study proposes a new well-pair design called toe-up SAGD, in which the toe of the producer is partially located above the shale layer.Sensitivity analyses of various preheating methods and parameters were conducted to derive the optimal preheating operating conditions.Furthermore, performance enhancements of toe-up SAGD were confirmed by comparing the productivity indicators and NPV with those of conventional SAGD.Finally, a feasibility study was evaluated by applying the toe-up SAGD to a heterogeneous model considering the reservoir property of the real field.