'oliver.gump' pid='78325' datel Wrote:
'Kaliboo' pid='78274' datel Wrote:
'bdahl385' pid='78266' dateline='<a href="tel:1481516 Wrote:. Correct. Recall is poor but I think I recall that we hit top of pay ~50-100 feet higher than expected in a well in the last 2 years. I don't recall whether the base also was shifted up by a similar amount, but if so, then you can imply that the reservoir is maintaining constant thickness and sloping and infer that dip angle in the direction of the slope. Erosion, scouring and other depositional processes can change the thickness. That's how they project the top and bottom depths in the next wells. The further away from existing well control, the less certain. Presence of faults changes the whole picture and can dramatically change the pore pressure gradient.
'Kaliboo' pid='78241' dateline='<a href="tel:1481386 Wrote:
'ArtM72' pid='78240' dateline='<a href="tel:1481382 Wrote:casing shoe depths are determined by pore pressure and frac pressure gradients in the earth. They tend to increase as you drill deeper so that requires an increase in mud weight. A wide variation from well to well is an indication of very different geology or encountering steeply dipping beds of the same stuff at different depths.
Is there anything we can glean from the 13-3/8" casing size down to 1,300 meters? This pic from Wike show a 13-3/8" casing to 4,000 feet leading to a 14,000+ foot TD hole. https://upload.wikimedia.org/wikipedia/commons/d/d8/Casing-Diagram.jpg
In laymen's terms, I believe Kaliboo has stated that we cannot infer planned TD of this well based on what size casing has been set at the stated depth.
Kaliboo, you are correct, at Ant 5, the top of the reservior was found to be 230m higher than expected [1] however the base of the reservoir was not shifted up higher. This means that the reservoir is significantly bigger than first estimated, yet the numbers went down when it got to a "deal".
Oliver - You bring up a very interesting point ....."base of the reservoir was not shifted higher" ....."significantly bigger " !!! [ As the Magombo Guru says.....notice the 3 exclamation points.] Humm .