The EIA analyzed EURs from more than 5,000 wells drilled into the Eagle Ford shale formation in Texas between January 2008 and June 2013. The average EUR was almost 170,000 barrels, but it has been rising, with wells drilled in 2012 (191,000 barrels) and 2013 (169,000 barrels) far more productive than wells drilled near the start of the play in 2009 (57,000 barrels) and 2010 (117,000 barrels).
There is enormous variability in the play, with wells in DeWitt county expected to average 334,000 barrels compared with 226,000 in Karnes and 80,000 in Webb. Even in DeWitt, EUR varies from 98,000 barrels (25th percentile) to 440,000 (75th percentile).
But across the United States there is a clear trend of rising average EUR from shale wells.
Productivity improvements can be traced to several factors. Shale producers are drilling and fracking longer laterals, increasing the amount of shale accessed by each well.
Through a combination of trial-and-error and better seismic work, drillers are increasingly able to target the highest-yielding parts of shale plays, improving average recovery factors and minimizing the cost of drilling subpar wells.