Listened to the webinar again and noted some tasty comments by Scott:
2.25 - In Upper Angwa, filled from the first sand that we encountered to the bottom sand that we encountered with a 900m gross interval so far
3.28 - Gas shows and fluorescence indicating a very rich source rock that we have with potential gas and condensate or light oil if we look at the fingerprints so far
13.10 - At the moment, we have a lot of zones that have gas in them. It doesn't matter what parameters we use, from a resistivity point of view and any of the other cut-offs that we need, those rocks contain gas. We have some other intervals which are more ambiguous because of the low resistivity that is still above what we believe is the baseline resistivity of the water but these could potentially be in the light oil columns
14.30 - We have proven that there are hydrocarbons in the rocks, certainly gas and potentially light oil as well, and now we just have to go acquire a sample
17.00 - In the pebbly Arkose we have got some potential gas zones and potential light oil zones that we need to go investigate with the sampling tools
28.35 - The source rock that we have now seen in the Upper Angwa, which is where we always thought it would be, is a very good source rock. So we've got some work to do now, we have a much better calibration point we can go away and do some migration pathway modelling and what that looks like in terms of charging these other structures (BaoBab) around the basin. The premise of BaoBab was that it was charged from some other source rock in addition to the Upper Angwa
39.15 - We are looking at potentially gas and also light oils. So gas definitely because of the resistivity from what we calculate from the saturation, that's also present in density neutron cross-over which also indicates hydrocarbon fill
Scott continually mentioned that the Upper Angwa was thicker than expected so I messaged Dan to get some more insight:
"If you look in any of their pre-drill presentations, they have Formation Tops mapped on the seismic (the coloured lines). In 3D those surfaces form structures from which they planned the well trajectory. It was a guess based on the information they had. When you drill, you get surprises, good and bad. In this case, the Upper Angwa is thicker than they expected. This is either because the seismic depth conversion needs adjustment, or it is just thicker than expected. They thought the overburden would have more sand in it, so used slower seismic velocities to depth convert. There was more shale in those units, so seismically it’s faster (shale is denser so the seismic waves travel faster). This means their original surfaces get “pushed down”, so are deeper. Once they finish the ST they can run the VSP and tune the seismic velocities and create a different depth model to drill off in future. It’s definitely positive that they kept finding what appear to be reservoir-seal pairs even at the final TD. It means there’s likely a lot more down there."Essentially, IVZ originally thought the Lower Angwa would start at 3,500m. However, we are still in the Upper Angwa at 3,920m. Don't forget we are still 300m downdip off the crest of the structure. So given Upper Angwa has a greater resource estimate of 4.1Tcf compared to 2.6Tcf, it is obvious that having a thicker Upper Angwa is extremely positive.
REMEMBER, ERCE only set the P10 Gross Rock Volume for each horizon up to a maximum hydrocarbon column height of 650m in the Lower Mukuyu horizons when they calculated the resource estimate to be 4.1Tcf for the Upper Angwa (20Tcf In total). The crest of the structure is 300m above where the well encountered the top of the Upper Angwa and so far IVZ has encountered 900m of gross interval in the Upper Angwa and they haven't even hit the bottom yet.
ERCE only used 650m column height starting at the crest of the structure 300m above. This makes 550m of potential hydrocarbon intervals not calculated in the 4.1tcf resource estimates... and there is the potential that more intervals were missed due to not hitting the bottom of the Upper Angwa yet. Given that IVZ was still hitting hydrocarbon intervals all the way down to 3,920m there's a good indication that there may be 1,200m of potential within the Upper Angwa Structure. Seems that there still was no spill at 3,920m
Scott even comments on this in the webinar at 48.20mins:
Given that we have had a thicker Upper Angwa interval, and the lateral extensiveness of the sands, we'll be able to calibrate, hopefully with the seismic, all this data now to get a better handle on the resource size.
Yet for the ERCE resource estimate, you still need to factor in the net-to-gross, sand/shale ratios etc which will definitely impact the resource potential. IVZ has more conclusive data now though so it will assist the revised resource estimate.
