A growing number of Chinese and Indian oil companies have acquired stakes in Northern Colorado's oil fields, a move sure to shift some profits outside Colorado and, for that matter, the nation.

Foreign interests have long snapped up stake in fields across the country, plowing billions of dollars in domestic producers. But the trend is still relatively new in these parts, fueled by the advent of horizontal drilling and fracturing.

Not everyone welcomes it. Beyond sending profits overseas, there are concerns about foreign interests accessing U.S. technology. Worries also exist about the extraction of American resources by foreign oil companies adding to the nation's trade deficit.

"You could make an argument that you'd rather have domestic companies owning those assets," said CSU professor of finance John Elder.

In part, that's because of concerns that exporting more natural gas could mean higher prices for U.S. homeowners.

"I am worried that exporting America's natural gas would raise energy costs for American consumers, reduce the global competitiveness of U.S. businesses, make us more dependent on foreign sources of energy," Massachusetts Congressman Ed Markey, a Democrat, wrote in a letter to Energy Secretary Steven Chu earlier this year.

So far, none of that has transpired. Natural-gas prices in the U.S. are, at the moment, at historic lows and the nation's dependence on foreign oil is declining.

Also, there are strict rules governing the export of oil and gas from the United States, and the government must approve of any project.

Still, foreign investment makes some nervous, and both China and even India are huge consumers of energy in all forms.

What's more, there's nothing modest about these deals.

Since 2010, Chinese companies have invested more than $30 billion into oil and gas deals in the U.S. and Canada, according to various reports.

Locally, Chinese oil giant CNOOC International last year bought a 33 percent interest in 800,000 net acres in Northern Colorado and southern Wyoming from Oklahoma City-based Chesapeake Energy Corp.

More recently, Houston-based Carrizo Oil & Gas in October reached a joint venture agreement with subsidiaries of OIL India and Indian Oil Corp., both based in Delhi, India.

The Indian oil companies acquired a 30 percent interest in Carrizo's Niobrara assets in Weld and Adams counties for $82.5 million. The sale included about 18,100 net acres and about 555 barrels of oil-equivalent daily from 24 currently producing Carrizo wells.

The companies already are drilling wells together, said Richard Hunter, Carrizo's vice president of investor relations.

"Thirty percent of our Niobrara oil and gas production will be sold by Carrizo on their behalf, and the proceeds will go to those Indian companies," he said.

Robert Dougherty, an attorney for Dallas-based Thompson & Knight who represented the Indian oil companies in the Carrizo deal, said the law firm has seen growing interest recently from foreign oil companies seeking to acquire U.S. oil assets. Much of that interest has come from Asian companies as shale oil and natural-gas drilling has proliferated nationwide.

"Prior to 2010, there may have been a handful of transactions," he said. "Since then, there's been a pretty significant increase in interest."

The types of transactions vary. Some involve outright acquisitions of U.S. companies while others involve the purchase of just some of a company's assets, he said.

Elder suggested that foreign investment is welcome — to a point.

"There's some potential for concern that you don't want to sell off your long-run means of production in order to buy little plastic toys from China," Elder said. "That's oversimplified, but that's a sense of the type of tradeoff that you're seeing."

Stan Dempsey, a Colorado oil and gas lobbyist, said the abundance of oil and natural gas in the Niobrara and the desire to learn about hydraulic-fracturing technology developed in the United States have drawn foreign energy companies here.

American companies, he pointed out, also invest in resources abroad. When they do, they also pay taxes to foreign governments, just as foreign oil companies do here, he said.

"I don't think it's any different from an American company developing resources overseas," he said.

It might not be, but foreign companies own a greater proportion of U.S. assets at the moment than what U.S. companies hold in overseas interests.

In Weld County, some 40 companies represent about 99.5 percent of the production, according to the Colorado Energy Office.

Of those producers, two have foreign headquarters: Encana, of Calgary, Alberta, Canada, and Sundance Energy of Australia.

Encana, which drills natural-gas wells around Erie, has a large presence in Colorado. While around 55 percent of its shares are held in Canada, the company employs 800 people at its U.S. headquarters in Denver and 1,800 nationwide. It also runs a field office in Longmont.

These companies are vigorous in defending their interests in the U.S.

Investment by Encana in the wells it drills helps to create wealth locally, spokesman Doug Hock said. The company estimates that each drilling rig it operates creates more than 100 direct and indirect jobs.

Earnings by foreign companies may leave the country, but nearly all of the oil produced in Colorado stays in the United States, said Rick Margolin, senior analyst for Evergreen-based Bentek.

He explained that the "light" crude oil produced in the Niobrara is better-suited for domestic use. Heavier crude oil produced in Canada and Texas is more likely to be exported overseas.

In places like western Canada, "there's a lot conversation about the fact that the resource itself will leave the country and go overseas," he said. "We're not really dealing with that here."

Foreign companies also make investments in local infrastructure like oil pipelines.

"It doesn't really matter if the investment is coming from the East Coast or Chicago or overseas," Margolin said. "That infrastructure serves as the backbone for future production."