Looks like a total of 5000 DUC's in the US as of 31Aug. Rig Count was at 508 last week. It is going to take a while to work through the back log. At 42 dollars a bbl it might take 2 years to work through.
I don't have all the numbers to plug in, but I think the rigs drilling are mostly just maintaining the DUC numbers in more mature plays, even as wells are being completed. That would depend on the rate of completions. Often the completions are as or more expensive than drilling the well, but in some areas there is a time limit on how long production can be delayed. The situation puts downward pressure on frac providers rates if (and only if) the companies are leaving second and subsequent wells on a multiwell pad as DUCs and producing from the initial well to hold the lease.
If it was my call, with a major player, I would be installing production equipment at fire-sale prices, getting labor and services at lower, more competitive rates, and waiting on the actual completions for the other wells on the pad until prices went up. I'd have some frac crews busy just to be on the list when the rush started, and push to complete when the price started up or reached a profitable threshold. That comes from watching companies like Exxon continue to drill during low price periods to have product to take to market when prices go back up. If you don't have production to sell, you can't take advantage of price swings.
Smaller companies might do the same on a smaller scale, depending on financial health.