In this May 7, 2012 file photo released by China's Xinhua News Agency, Haiyang Shiyou oil rig 981, the first deep-water drilling rig developed in China, is pictured at 320 kilometers (200 miles) southeast of Hong Kong in the South China Sea. (AP Photo/Xinhua, Jin Liangkuai)

In 1947, 12 miles out into the Gulf of Mexico from the Louisiana coast, an oil rig dubbed "Kermac 16" began operating. It was owned by Kerr-McGee Oil Industries, and represented a major technological breakthrough: For the first time, humans were drilling for oil so far out at sea that they couldn’t glimpse land any longer. Granted, the rig could only drill in waters 18 feet deep. But it was a predecessor to today's profusion of advanced, deepwater drilling ventures that can now access ever harder-to-get hydrocarbon resources, in some cases in waters deeper than 10,000 feet.

While the explosion and subsequent spillage from the Deepwater Horizon in 2010 focused dramatic levels of attention on one risk from offshore drilling, there may also be another one -- actual conflict between the countries who lay claim to the waters that host such valuable resources. Such, at least, is the contention of a new study in the journal Energy Research and Social Science, which suggests that the growth of offshore drilling around the world has gone hand-in-hand with more maritime disputes, sometimes involving threats of violence or even violence between states.

"It’s someone saying, 'I want this and I’m willing to fight you for it' -- or showing through their actions they’re willing to fight, so maybe moving a naval ship into the area, or actually firing weapons," says Elizabeth Nyman, the study's author and a political scientist at the University of Louisiana at Lafayette. So we're not talking about large scale military actions here -- but still conflicts that are hardly trivial between world powers.

As an example of such conflicts, Nyman cites a recent dispute between China and Vietnam over the seas near the Paracel Islands in the South China Sea -- one of a number of such disputes involving China and other countries including Japan, Vietnam, and the Philippines. "China moved a drilling rig into disputed waters, there were anti-China riots, Vietnamese fishing vessels were purportedly attacked by Chinese vessels," says Nyman.

Nyman's paper takes the year 1947 -- the year that Kermac 16 began its work -- as a technological break point in the development of offshore drilling technologies, noting that by 1956, less than 10 years later, successful drilling was being performed in 350 feet of water. At around the same time, she notes, Harry Truman issued the 1945 Truman Proclamation, in which the United States asserted a territorial right over all the resources contained in the country's continental shelf. The proclamation explicitly noted the “long range world-wide need for new sources of petroleum and other minerals,” and observed that technological advances were placing subsea resources within reach.

But the US's assertion of its rights to ocean areas prompted other countries to do the same. This process, notes the paper, has produced a "miasma of confusion and conflict," with oil resources being a primary cause.

To demonstrate a trend in maritime conflicts, Nyman examined a database that tracks "militarized interstate disputes," defined as "the threat, display, and/or use of force by one state against another." She pulled data for the 20th century in particular and controlled for factors that included changes in the price of oil, whether the states involved in the conflict were democracies (which are known not to fight each other very often), and the relative military capacities of the countries involved.

Sure enough, there were more militarized interstate disputes involving ocean areas thought to host oil resources after 1947 than before, controlling for these variables -- but the trend was not true for other territorial conflicts. It was only in the oceans. "Contested maritime areas with oil and gas resources were more likely to see conflict after the extraction of those resources was an accomplished feat," notes the study.

The paper is "a solid piece of research," says political scientist Sara Mitchell of the University of Iowa, who is familiar with the study. "I like how she shows the effect of post 1947 years to be significant for maritime claims but insignificant for disputes involving land borders or ownership of islands."

The findings may be particularly relevant in light of climate change -- the rapid melting of the Arctic is expected to set off a new resources race, as countries with Arctic seascapes like Russia, Canada, and the US move in to exploit the hydrocarbons deep beneath the surface. "A lot of people are trying to figure out what’s going to happen up there," says Nyman. "There’s a lot of different ideas."

"Most visions are peaceful," she adds.