The initial steam chamber that developed during the circulation phase of a Steam Assisted Gravity Drainage (SAGD) process impacts the efficiency of bitumen recovery tremendously. The circulation phase, during which both horizontal injector and producer in a SAGD well pair are put under circulation, is designed to establish inter-well communication and create an initial steam chamber. It is desirable to know the mid-point temperatures between and along the horizontal well pair so that any development of the steam chamber can be predicted.

This paper proposes a new analytical model to predict the temperature fronts and heating efficiency between and along the horizontal well pair during the SAGD circulation phase. By using the exponential integral solution for radial heating in a long cylinder and superposition in space for multi-heating sources, the proposed model can be used to predict these temperature profiles, provided that the steam temperatures or pressures are known during the circulation period.

Knowing temperature profiles between and along the horizontal wells is of great importance when deciding how to design the circulation parameters, where to modify the process, and when to switch to the SAGD production phase in a timely manner. The results can be optimized under various operational conditions, wellbore profiles, tubing sizes, and convection flow effects.

The proposed model is easy to use, provides quick results, and ideal for updating during operations. This model is also advantageous compared to numerical simulation because it reduces computational time if many well pairs are involved in the study, and models accurately any variation in distance between the wellbores. Generic data is used in this paper to illustrate the model application.

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