The Nsolv Process
How It Works
Step 1 – Solvent purification. The Nsolv process requires a substantially pure solvent in order to function effectively; therefore, the first step in the process is to distill the solvent, removing non-condensable gases such as methane, turning it into a high-purity solvent.
Step 2 – Solvent heating. The high-purity solvent is then warmed and turned into solvent vapour.
Step 3 – Solvent vapour injection. Warm solvent vapour is pumped into the injection well at a rapid pace. When it reaches the extraction chamber, it condenses and dissolves the bitumen, draining downward to the production well as a solution of both solvent and oil. Naturally occurring water and non-condensable gases are also carried along and out of the reservoir. Coke-forming asphaltenes are sequestered.
Step 4 – Separation. Upon being pumped up to surface, the partially upgraded oil mixed with solvent is separated into three components: oil for sale, solvent and naturally occurring water. The oil is sent to refineries for further processing. The solvent is pumped back into the separator and re-purified before being recycled back into the reservoir. Gaseous impurities removed from the solvent, such as methane, are used to fire up the solvent heater.
Step 5 – Solvent make-up. Nsolv estimates that a solvent quantity equivalent to 20-30% of the extracted oil must be added to the system as make-up. As the chamber grows, the make-up solvent is continually replenished. At the end of a well’s life, the solvent can be recovered and reused on another well or marketed.