"However, there are growing signs that the U.S. shale industry could be reaching the end of the low-hanging fruit. Or, more specifically, drilling costs are starting to rise and the enormous leaps in production that can be obtained by simply adding more rigs also appears to be running into some trouble.

According to the EIA’s Drilling Productivity Report, productivity (as opposed to absolute production) is set to fall next month in the Permian Basin. In other words, the average rig will only be able to produce an estimated 630 barrels per day of initial production from a new well, down 10 b/d from the 640 b/d that such a rig might have produced in May. That is convoluted way of saying that the ever-increasing returns on throwing more rigs at the problem might be hitting a ceiling."

https://oilprice.com/Energy/Crude-Oil/Has-Permian-Productivity-Peaked.html