happy times ahead, page-42

avarist,

I can't for the life of me understand how the paper you linked to (which discusses the origin of saline waters from within PV gas field and identifies them as locally-derived) has the slightest impact on the sealing characteristics (or lack thereof) of a sandstone several hundred metres above the reservoir unit. Are you just trying to say that quartz overgrowths can form post-diagenesis?

The original statement was ridiculous not so much for the idea of a cemented sandstone being a seal (though I have big doubts about it) but because of the statement that a hard sandstone is a great seal that is "more often than not" going to have oil below it.

This is patently false. This is not some special seal that is superior to the prognosed shales, or more likely to have oil below it. Actually, it's LESS likely to have oil below it - a shale is a better seal than a hard sandstone, and there are at least two shales in this well optimally located to act as a seal. There are probably even shale beds within the Mereenie itself that could act as a small seal - and they are probably regional, where by your argument this sandstone is related to the anticline formation and would therefore a) be comparatively small and not seal much oil in, and b) not be a seal all the way from the source kitchen.

So sure, it's POSSIBLE that there could be oil below this. But it's not like seal was a major risk here - reservoir is the big risk. As far as all the seals in this well are concerned, this one would rank at the absolute bottom of most likely to contain commercial oil.

If anything, it's a pretty bad sign - because if this sandstone can be cemented tight, couldn't the target reservoir be too?

And to suggest, as the original comment did, that this is just about a sure thing, is plain ramping IMO.

I still think we'll have oil shows in this well, probably in the Stairway, but run into the same problems with tight formation as we had in JW-1. And if, by some Creator-inspired miracle, we do get oil here, things are going to be looking very good for the Stairway - because as a local seal, the only place for oil to come from here would be from directly below it.