There’s no question that shale gas production—enabled by hydraulic fracturing techniques—has boomed in the US with major effects on the energy industry. The price of natural gas fell and cleaner, more efficient gas-burning power plants have sprung up to usurp old coal plants. This has been seen as a long-term shift in the fossil fuel landscape, but it can’t last forever. The obvious question is just how much shale gas is down there to be had?

The most recent outlook from the US Energy Information Administration saw US production slowing from the exponential trajectory of the 2000s, but still increasing through 2040. A news article appearing in the journal Nature this week highlights a major research project run by a group at the University of Texas at Austin that foresees much lower production. Their analysis forecasts peak shale gas production in 2020, falling to half the EIA’s estimate by 2030.

The reason for the difference is mostly a matter of resolution, according to the Nature story. The EIA has relied on county-level production statistics, while the UT-Austin researchers have drilled down to one mile resolution. That makes it easier to account for “sweet spots”—the portions of a shale layer with the physical characteristics most conducive to producing natural gas. The reason for fracturing these rocks to free the gas is that they’re too impermeable for the gas to move through them, so this isn’t a case of the first few wells bleeding the store dry. But to the extent that sweet spots can be identified, they’re typically targeted for drilling first. That means that subsequent wells in the area may be significantly less productive. And that could translate into the end of the shale gas revolution arriving well ahead of schedule.