Post by
oldcompanyman on Sep 27, 2021 5:35am
For OIL_RUN
Hi OIL_RUN,
You may or may not have seen the below I posted here two days ago, could you please give it a quick sense check from a geoscience / formation evaluation perspective? Especially for the MWD part and its relevance as a strong primary indicator, this is what I physically saw on most exploration wells I drilled but my background is not in geoscience, I'm an ex-toolpusher so I know my limits.
Thanks for your help,
Their timing still does make sense because, as I believe I had written before, the current sections are being drilled fast but later on it will have to slow down.
As a general outline, until the intermediate string (i.e; the 13-5/8" or potentially 14" by 13-5/8", in the highly unlikely case a full 14") is set, you can drill fast, because you are mostly going through "geologically meaningless" shale (and similar) layers. Any proper geologist would kill me for stating it that way, of course any layer is meaningful (very good hint at the press release regarding the formation tops coming as expected) but from an oil&gas perspective not very meaningful. The reason you can take the liberty of going fast is that if your geological model is correct, there is nothing of interest, neither nothing that can create any danger for you, in these depths. Note: of course you always have your various systems active to detect any danger (pressure anomalies, abrupt formaton changes etc) so that you can slow down etc, but my expectation would be that they drill down to somewhere around 5,000-5,500m without slowing down much and case that hole by the 10th of October, give or take a few days.
It has been a long introduction but the answer is coming.
After that point, when they will start drilling 12-1/4" through the intermediate casing, they will be aiming for the "top of the reservoir", in a section called also the "pressure ramp". The reason being that the pressure will, at some point, start to increase (it can happen fast), the gas content of the formations will/may increase and all the while you are looking for the "competent formation" where to set your 9-7/8" shoe (probably 9-7/8"; maybe 10" or even 10-3/4", doesn't matter for the present discussion). All of that, in an exploration well you need to do slowly, you do not know where the formations will come and what pressure the layers will have etc. I am trying to think of a decent analogy; imagine you're driving on a German autobahn at 2 o'clock in the morning and your headlights do not work. You could drive at 120 mph (the Germans allow it...), it might work out fine (there are ot many people on the road in the middle of the night) but you would still take it slowly I'd like to hope; you may bump into someone from behind or miss the exit, you have no headlights, it's exploration...
So, I would guess that under these circumstances they will set the production casing shoe at some point early November. Ballpark figure first week of November, I don't want to guess a more precise date 40 days in advance, it would not be professional. I know litterally nothing about that well's design (apart from the public data), have no PPFG data or offset well data so will not risk further guesses for that particular one; maybe they will already be there by the last week of October, with the production casing shoe set, maybe.
At that stage, they only have the reservoir to drill and they have isolated everything above, say, 6,300m. Note: this depth is just an example and to answer your question, with the pdf's on their website, I cannot figure out anything meaningful and I guess a geoscientist will do any better, there is very limited data, as would be expected.
The answer is coming.
So, when they start drilling the reservoir, very quickly they will know if there is something to write home about or not. They were referring to 3 layers, my guess is they will take around 7-10 days to drill, depending on many factors (evolution of pressure, hole conditions etc) and during these 7-10 days the MWD triple combo gives you density, porosity, resistivity data + the gamma rays. With all of that, you already know to a very high certainty level if there is oil or not (I say if "there is", not if "it is able to flow"). So, repeat, by mid-november, they will know if there is oil.
At some point they will run wireline to have proper logs, with better resolution than MWD; it will take some days but not weeks. I say at some point because the work plan is not very detailed or at least I am not aware of; are they going to core (I have not read anything about it)? Are they going to take sidecores (also very useful and les stimecosnuming but I have not read about it either). Most importantly: are they gonna test? The welltest is the ultimate proof (oil is there and it flows) but in a lot, lot of exploration wells of the last decade there was no more tests (some countries do not allow welltesting anymore or impose a lot of red tape + the knowledge we have gained on the flow capacity of a well seems also to have evolved and not always require a well test on the initial well). So, the uncertainties on the operations at the reservoir level are the source of my view about the last month i.e. 15th of Nov to "early December" of operations. Maybe they have planned to test, maybe not, it will not make a big difference for us anyway, by mid-November everything is gonna start to be "visible".
I hope this covers some info you were looking for.