The performance of steam assisted gravity drainage (SAGD) depends, mainly, upon reservoir characteristics e.g. porosity, permeability and heterogeneity, well bore hydraulics e.g. steam quality, the length and size of wellbores and operational parameters e.g. reservoir and wellbore subcools. However, in reservoirs with underlying bottom water, the performance of SAGD depends on vertical offset between bottom water and producer and pressure differential between bottom water pressure and bottom hole flowing pressure of the producer. Bottom water can act as a heat sink is a known fact, therefore, it can affect project oil rate, steam rate, steam oil ratio (SOR) and, ultimately, the economics of the project. Bottom water can affect heat transfer within reservoir by the injected steam in case of water coning or steam loss to the bottom water. Produced water chlorides concentration (PPM) is an important indication of bottom water coning because of difference in the chemistry of injected steam and bottom water. The chlorides material balance depends upon water saturation in bitumen zone (connate water), formation water chlorides concentration, produced water chlorides concentration and water cut. This study will shed light on significant impact of bottom water coning on SAGD performance through reservoir simulations. It will, also, describe contribution of each of the aforementioned parameters (water saturation in bitumen zone, formation water chlorides concentration, water cut and produced water chlorides concentration), which is very significant, on chlorides PPM material balance for bottom water coning analysis. And it will, also, describe how the safe limit of produced water chlorides PPM (produced water chlorides PPM at which no bottom water is produced) is affected by each of these parameters.

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