Production of extra heavy oil or bitumen by means of SAGD (Steam Assisted Gravity Drainage) requires the generation and injection into the reservoir of a great quantity of steam. A corresponding quantity of hot water is then produced along with the mobilised oil. Bearing in mind existing and future environmental regulations, it is likely that partial or even total recycling of this produced water back into steam will become mandatory.

The complexity of the water treatment scheme required depends on the water characteristics, the steam boiler specification (OTSG or conventional 100% steam boiler) and whether or not waste water disposal is completely eliminated (zero reject) or not. SAGD developments have some specific water treatment issues which need to be addressed, for example the high silica content of the produced water. This paper will present different conceptual designs for a 300 000 bwpd water treatment plant. The different schemes discussed include an OTSG boiler, a conventional boiler and the zero disposal option. The various options available for process equipment will be presented, together with two different salinities of produced water and their impact on process design. Included will be an evaluation of capital cost and operating costs elements.

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