As it approaches $50, the drilling is going to slow way down. When the drilling doesn't keep up with the fast falling production rates from these tight formations, the inland supply in the US is going to fall and the price will stabilize higher than $50. That price just will not support the continued investment in places like the Bakken, Eagle Ford and other shale formations.
Maybe the technology would allow for wildcatters again and the John Q Public could drill his own well and sell it.