Nangwarry - The co2 well worth up to $1.3 billion that the markets ignoring

I think most punters don't understand what co2 is worth so let me spill out my workings for it. Keep in mind I'm just a retail punter too so go and fact check what I say, and please correct me if I'm wrong.
First of all for reference - Neil Gibbons tells us that co2 fetches about $300 per tonne at the 7 minute mark on the video below.
Now with a bit of playing around, I found that 25bcf (Our Best estimate before today's announcement) is around 1.3 billion kilograms.
I came to that by looking at the nearby Caroline-1 well, which was a 15bcf system and produced 810 million kilograms over its lifespan. With 25bcf being 66% higher than 15bcf, that puts Nangwarry at 1,350,000,000 kilograms, or 1,350,000 tonnes.
At $300/t, that puts Nangwarry at $405m of co2. Keep in mind that VEN has only 50% of Nangwarry, so thats about $200m net to VEN.

Now for the fun part...
If Nangwarry comes in at the old High estimate of 82bcf, that would put VEN's 50% share at around $650m

Today's announcement says that they're expecting the end result to be somewhere between the mid-high of the estimate.
My guess is that they land halfway between $200m and $650m for VEN's 50% share of Nangwarry.

Now that I've had my fun, someone please tell me if I can or can't accurately guess the amount of co2 in Nangwarry by adding 66% of Caroline's production to it. Maybe it doesn't go up linearly like I'm assuming.
Thanks

Oh, and then there's the Vali and Odin prospects which have already found gas and should pump out up to $50m a year (with around 10 wells running) with production expected to start within a year.