The production of extra heavy oil or bitumen through Thermal methods (e.g. SAGD - Steam Assisted Gravity Drainage) requires the generation and injection into the reservoir of significant quantities of steam which is finally recirculed with the produced bitumen. Considering the need to minimize fresh water consumption and the possibility of increasingly stringent environmental regulations, it is likely that maximization of the recycling of the produced water into steam will be mandatory.
The SAGD water treatment scheme is complex because it depends on the water characteristics, the steam generator type selected (OTSG or conventional boiler) and the decision to completely eliminate waste water disposal (zero liquid reject) or use other waste handling and disposal methods. SAGD water treatment also faces some additional specific challenges compared with oil fields worldwide, such as the high silica content in the produced water.
An overview of the current water treatment process options for SAGD will be presented, followed by a new patented process called SIBE (ie Silica Inhibition and Blowdown Evaporation). The principle of this new process is based on TOTAL's research in the area of silica inhibition and an optimized application of conventional water treatment equipment with Zero Liquid Discharge process (e.g. evaporators and Crystalliazer). An estimate of the economic benefit of the new SIBE process relative to conventional process schemes will be presented.