New SAGD model for oil production using a concave parabola steam chamber geometry

In this paper, a new steam chamber growth model using a concave parabola interface is presented. Steam chamber shape is crucial in describing the expansion of injected steam and the propagation pattern of the temperature of the steam front towards the producing well. Steam chamber evolution is particularly important for predicting oil production during steam assisted gravity drainage (SAGD) processes. The new model is derived based on the orientation of the temperature isoline obtained for the underground test facility (UTF) project, the results of several experiments, and the numerical simulation of SAGD processes for major field projects. The analytical description of this steam chamber growth pattern will assist in evaluating and developing fields using SAGD scheme. The model employs the concept of heat conduction involving a moving solid to estimate the steam chamber interface temperature profile and, eventually, the oil production rate and associated steam injection rate required based on an energy balance approach. This study builds upon the assumptions of Butler and Reis' linear interface by introducing a parabolic steam interface. It is demonstrated that the new model predicts oil production and steam injection rates with higher accuracy than existing models. It also showed the strong variation of oil rate with time unlike the constant rate assumption. The results of the model are compared with the experimental data from Cheng and Butler, simulation with a CMG STARS simulator and the results of the UTF phase B project, which show better agreement and robustness.