Domestic oil production has rocketed by roughly 70 percent over the last six years to 8.7 million barrels a day, and imports from members of the Organization of the Petroleum Exporting Countries have already been cut roughly by half. With domestic oil production growing month after month, many oil experts predict that the country’s output will rise to as much as 12 million barrels a day over the next decade, which would mean the country will be swimming in oil the way it is currently dealing with a surplus of natural gas.

Analysts at Turner, Mason & Company, a Dallas engineering consulting firm, say the country could hit a saturation point when production hits 10 million to 10.5 million barrels a day, at which point large exports will become necessary or drilling and production may have to slow.

“A flood is upon us,” John Auers, a Turner, Mason senior vice president, recently told energy executives at a Houston oil conference. “We are getting close.”

The country will continue to import some grades of oil for years to come, but energy experts says oil exports should rise significantly over the next few years because of a mismatch in the type of oil the country now increasingly produces and the mix of oil its refineries were designed to process. Shale oil is predominately light, sweet oil, meaning it is low in sulfur content and flows freely at room temperature. American refineries can refine only so much of it because they were structured to process abundant amounts of much heavier crudes imported from Mexico, Venezuela and Canada. That is leading to a crude-oil glut in parts of the country’s midsection already — which has pushed oil companies to lobby for expanded exports and directly led to that recent shipment from Galveston.

Image The United States has strictly limited exports since the Arab oil embargo, when President Jimmy Carter wore a cardigan sweater to encourage lower thermostats. Credit... Associated Press Photo

The Galveston sailing was historic because the United States has strictly limited exports since the era of the Arab oil embargo, when President Jimmy Carter wore a cardigan sweater to encourage lower thermostats and other measures to limit the country’s dependence on foreign oil. In sweeping legislation, Congress in 1975 directed the president to prohibit the export of oil as “consistent with the national interest,” although broad exemptions were allowed. Various administrations since then have permitted limited exports, including shipments from Alaska’s Cook Inlet and to Canada, but the issue rarely came up because the country was seemingly running out of oil.

Then suddenly the energy world changed, and parts of the Midwest and the Gulf of Mexico regions were overflowing with light grades of crude, leading to a slump in prices and a gap of as much as $15 between the United States oil benchmark and the prevailing Brent world price. Unable to export the excess light crude, the industry exported refined products like gasoline and diesel instead. In 2011, the country pivoted from being the world’s largest importer of petroleum products to becoming one of the leading exporters.