EPA is aware of the releases, and has estimates of how much is released at each well. Unfortunately, many of their estimates had not been updated in years. A recent update indicates that releases from "completion" of horziontal wells (e.g., Marcellus) releases about 9000 times more methane than they had previously estimated. While this makes natural gas more of a greenhouse problem, it is still marginally better than coal. But the data show that the real answer to climate change has to be to conserve energy and switch to non-fossil fuel alternatives.