According to wikipedia: "Since the 1990s, the [US] oil market has been free of most regulations."[1] My understanding was that the US oil boom was caused by technological advances that enabled better exploitation of shale oil deposits. Also according to this graph[2], the boom really starts around 2011-2012, not 2015.

[1] https://en.wikipedia.org/wiki/Petroleum_in_the_United_States... [2] https://en.wikipedia.org/wiki/Petroleum_in_the_United_States...