Disclaimer: I have no formal (or, for that matter, informal) training or experience in the oil sector, so I'm probably getting ahead of my headlights with regard to some of the comments I will be making later.
First, this. Earlier this morning I mentioned that there seemed to be a "quantum" jump in the quality of the Bakken wells (based on 24-hour, 30-day, 60-day, and 90-day IPs) when going through the 2017 Bakken permits. It appeared that somewhere between 2016 and 2017, things in the Bakken changed significantly with regard to better wells.
One almost wonders if the "near-death" experience visited upon the Bakken operators by Saudi Arabia (2014 - 2016) forced "them" to improve their strategies and technologies.
I remember early on, during this time, maybe even as late as 2016, really, really smart oilmen simply said, "more sand, more oil." It was all about simply adding more and more sand.
But look at the completion strategies in 2018 and going forward: maybe they're using more and more sand in the Permian, but in the Bakken, it appears we're leveling out at around 8 million lbs and fewer, rather than more, stages. Granted, "we're" drilling in the "best" spots in the Bakken but that would be true in the Permian, too, I assume, and yet some of the best Bakken wells I've seen used less than 8 million lbs sand and only 35 stages.
Much could be written, but let me post what a reader sent me. It's obvious he's been thinking about this even more than I (have been thinking about it). Here was the reader's note [the comments in red/bold are mine, not the reader's]:
Somewhat brief, hopefully accurate, theory concerning the increase in IPs in the 2016 - 2017 timeframe ...Isn't that interesting?
Many operators had, by that time, started to declare that diverters were being used in completions.
EOG most probably started this earlier as they depicted controlled, HIGHLY increased fracture intensity in their presentations prior to 2016.
Fast forward to today and the ramifications of Extreme Limited Entry (XLE) ...
I have studied the September, 2018, article from aogr.com from Liberty Resources regarding Extreme Limited Entry in attempts to fully "get" what is happening and project future implications. [To repeat: the September, 2018, article from aogr.com from Liberty Resources regarding Extreme Limited Entry.]
In a ultra condensed nutshell, what these operators are doing is maintaining a VERY high pressure "bubble" underground so as to induce fractures (technically, opening up pre-existing fractures. This is a crucial - yet often overlooked distinction).
This pressure "bubble" functions best if it can be maintained at 1,500-2,000+ psi to induce connectivity (create complex fractures).
By identifying homogeneous rock that will tend to fracture with similar pressure levels, thief fractures will be minimized. (This directly ties in with the number, length, and placement of stages as each stage is a somewhat 'stand alone' entity. [This is so incredibly cool.]
Using extremely sturdy metal, the perf entry points - precisely located - will not enlarge as a consequence of proppant friction. A ton of sand per linear foot is a LOT of scouring material.
Perf clusters now number 13 to 15 per stage, up from 3 in earlier years.
Diverters, both near wellbore and far field, are used to temporarily block undesirable frac propagation so as to bring about an optimal case of Stimulated Reservoir Volume (SRV).
Speculative bonus regarding halo effect?
I am starting to suspect that later frac jobs are deliberately "touching" earlier wells' drainage area by fracturing and propping unstimulated areas of the parent wells' rock and enabling the newly frac'd/propped reservoir to flow into the older wells' wellbores.
Now this, for free. I am providing a link at no extra cost -- free to all subscribers -- JPT Extreme Limited Entry Perforating. I had completely missed this paper. Again, thanks to a reader I've learned more about the Bakken. I find this absolutely fascinating.
Yes, I know. I am inappropriately exuberant about the Bakken.
By the way, the article the reader was referencing: an "editor's choice" article from September, 2018.
I've been focused on the halo effect, what is now called the "parent well uplift" phenomenon. It's very possible the oil industry was more concerned with damaging parent wells when drilling new wells, which ultimately led to extreme limited entry perforating. I agree with the reader: my hunch is that the operators are choosing very, very carefully where best to put daughter wells and how to best complete (frack) them.
The operators are probably more concerned about preventing damage to existing wells. I'm fascinated by the parent-well uplift phenomenon. It appears these may simply be two sides of the same coin.
Again, as mentioned earlier, I'm probably getting well ahead of my headlights.