RE: Educated opinions please10 Dec 2018 13:31
JTD - The lateral extent is perhaps the shorter term target for appraisals, in the announcement they highlight the surface distances between Mariposa, Indico and the proposed Sol site and say they are now planning further drills to essentially establish the footprint of the find.
The low water cut enables a simpler oil in place calculation based on the inferred volume of the trap, ie they don't have to account for water volumes, that's why they said: 'Further updates will be provided as operations develop and the volumetric models are refined based on logging and testing data.' Basically they are deferring making an oil in place / recoverable statement until they know the size of the reservoir, but they are clearly implying a field diameter of greater than 13km. Once they have the log and test data on flow and density they can say what is in place.
Having said that, given what we already know... assuming Indico is the centre of the field rather than the edge, and Sol and Mariposa represent the edges, then we have an approximate sector of a sphere containing the oil 13km wide and 208 feet thick net.
Using a (highish) rule of thumb of 1g of hydrocarbon per cm3 in a 15% porous rock for API 41 oil , V=2/3 x pi x r2 x h , = 2/3 * 3.14 * (6.5*10^5)^2 x 6340 = ~ 1.6Bn BoE.
So the reservoir is not circular, the thickness not uniform, the % hydrocarbons could be lower based on sand porosity and API and so on, and flow rates might make the % recoverable lower. The radius may also be lower depending on Sol, but right now you have to assume Indico is the centre as it is much thicker net pay than Mariposa, but remember Mariposa may not be the edge either.
The bottom line is like my earlier post, they have a find likely in the hundreds of millions of barrels, and simply don't know how much yet until they have done a lot more testing. Far more educated people than me will be able to take the numbers and make a more accurate guess, which is why they have published a subset of the numbers now. Its a for sale sign for a billion dollar asset wrapped in a hundred million dollar company.