Tuesday, May 08, 2012

MEG uses less steam by injecting mystery gas

There's a short article on the Oilsands Review (unfortunately behind a pay-wall) on an experimental new SAGD method at MEG's Christina Lake property. Basically, they inject a non-condensible gas (ie a gas that won't turn to liquid in any of the pressures and temperatures present in the steam chamber or well) in place of some of the steam. This gas holds the pressure up while the remaining steam heats the bitumen as usual. The gas is apparently recycled. MEG reports no drop in production when switching to this method from regular "all steam" SAGD. In the first quarter of 2012 the method led to a steam oil ratio (SOR) of 1.8, which is exceptional even by MEG's standard (MEG's standard is closer to 2.5 to 2.8, which is one of the lowest in the industry). Two infill wells using the method showed cumulative SORs of about 1.0 at the end of March.
The method appears to be distinct from the various solvent injection processes being tried around the province.

They don't say what gas they're using, but I would guess nitrogen since it is a gas in all SAGD well conditions, is non-combustible, and is cheap and abundant. Note my use of the Oxford comma. Alternatively, it could be something like methane, which they have pretty handy (they already use a whole lot of methane for their steam generators). It might also work to lower the viscosity of the bitumen, although I've been told that methane is a poor miscible gas in SAGD conditions and the only purpose is to maintain pressure. Not sure if methane would be more dangerous than injecting an inert gas. The MEG website seems to suggest it is methane, but maybe they're just trying to mislead their competition and have all their wells blow up. If it is methane they're using, it seems only fair that they account for that somehow - they're still consuming natural gas, it doesn't really matter that they aren't using it to make steam but rather injecting it directly into the reservoir. 

While still early, this is a pretty interesting development. Significantly reducing SORs would be great news for the oil sands - it would mean cheaper production and lower natural gas use, which means less CO2 emission per barrel.

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