magnitude of dorado

I am trying to get a back of the envelope calculation for the magnitude of the Caley resource.

I appreciate that without an oil/ water contact , and the many assumptions needed, any numbers are potentially misleading, but the purpose is to try to get a grip on the magnitude we are talking about ie, is Dorado in the tens, hundreds or billions of barrels of oil?

So here is my attempt based on what we know and some assumptions.

The simple calculation for oil in place is essentially :

Rock volume x porosity x hydrocarbon saturation x 1/shrinkage.

Rock volume ... the areal extent of Dorado looks to be about 70 square Km, and will assume the reservoir is rectangular ( which it certainly isn't) and the OWC allowing this to be the area. The oil column was 79.6 meters... I will use 70 for the average over the structure.

Porosity = 20% ( as per release).... will use 15%

Hydrocarbon saturation was 82.5 % which includes gas, so will use 60% as oil saturation

Shrinkage of 1.4 which appears to be reasonable for the ~ 50 API oil

So oil in place is calculated as 7000 x 10000 x 80 x 0.15 x 0.6 x 1/1.4 meters cubed= 360 million cubic metres.

this equals 360 million x 6.3 barrels or 2.268 billion barrels oil in place.

Giving a 20% recovery factor we get 453 million barrels recoverable which gives CVN about 90 million barrels .

As mentioned, this potentially erroneous and incorrect but at least for me, it seems to correlate statements that Dorado may be the biggest oil discovery in Australia if the past 40+ years.

Changing any of the inputs gives huge variations to the result but this exercise for me helps to quantify if we are looking at Dorado as a baby, mama or papa elephant.

Please feel free to shoot this down in flames if totally incorrect... (I am not a geo but I think I can multiply)

Cheers

Dan