There has been considerable dispute over how many new wells required to keep production flat in the Bakken and Eagle Ford. One college professor posted, over on Seeking Alpha, figures that it would take 114 rigs in the Bakken and 175 in Eagle Ford to keep production flat. He bases his analysis on David Hughes’ estimate that the legacy decline rate fir Bakken wells is 45% and 35% for Eagle Ford wells. And he says a rig can drill 18 wells a year, or about one well every 20.3 days.
The EIA has comes up with different numbers. The data for the chart below was taken from the EIA’s Drilling Productivity Report.

The EIA has current legacy decline at about 6.3% per month for Bakken wells and about 7.7% per month for Eagle Ford wells. That works out to be about 54% per year for the Bakken and 62% per year for Eagle Ford. I believe the EIA’s estimate of legacy decline, in this case, is fairly accurate. For instance last month Mountrail County had over 30 new wells completed yet still declined by 6.4%. And in December 2013 North Dakota declined by 5.22% yet had 119 new well completions.
I have examined the last sixteen Directr’s Cuts and gleaned, I think, some important data… I think.

Rig count has averaged 189 rigs per mnth and has been fairly steady while new well completions has averaged 172 wells per month but has been highly erratic.
New well completions depends far more on weather and fracking crews than rigs. In October there was 650 wells awaiting fracking crews. At 172 wells per month that is almost a four months supply. And that is also what the average spud to completion is, 120 days.
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