As other commenters have pointed out, the US only overtakes SA for a few years before falling behind again:

"By around 2020, the United States is projected to become the largest global oil producer (overtaking Saudi Arabia until the mid-2020s)"

So maybe that part of the story is overblown. But perhaps more interesting is that the US will supposedly become a net exporter shortly thereafter:

"The result is a continued fall in US oil imports, to the extent that North America becomes a net oil exporter around 2030."

Source: IEA World Energy Outlook 2012 - Executive Summary http://www.iea.org/publications/freepublications/publication... [PDF]