Paris is always a good idea," Audrey Hepburn famously said in the 1954 movie Sabrina. Now it seems that exploring the Paris Basin is also a good idea.

France's sleepy Paris Basin will soon be enjoying investment levels it has not experienced since the late 1980s and early 1990s, when companies sank a flurry of wells seeking conventional targets.

Those efforts were largely disappointing: although its outstanding source rocks are estimated to have generated some 100 billion barrels of oil, the basin has produced less than 300 million barrels. Volumes peaked in 1988 at some 43,000 barrels of oil per day and had declined to some 11,000 a day in 2009, according to the French Energy Ministry.

Nonetheless, this over-the-hill conventional basin is currently one of the world's hottest destinations for shale explorers. That's because the big gap between generated oil and produced oil offers a juicy target, and Paris Basin rocks show strong analogies to the exceptional Bakken petroleum system in the Williston Basin.

In a remarkably similar set-up to the Bakken play, the Paris Basin's Banc de Roc limestone is wedged between thick, organic-rich shales of the younger Schistes Carton and the older Amalthees formation. The two shales, along with the slightly older Sinemurian shale, are part of the world-class Jurassic Lias Series.

In general, the Lias shales are found at depths from 500 to 2,700 meters, and range in thickness from 25 to 450 meters. They have Type II kerogen, contain total organic carbon contents of up to 12%, and lie firmly in the oil window. Such reservoir characteristics as porosity and permeability fall comfortably in line with measurements taken from Bakken wells.

The first exploration efforts in the Lias shale play are advancing.

Last year, Calgary-based Vermilion Energy Inc. recompleted two existing wells in shale intervals. The company has not reported details, but has said it plans to drill two new wells this year, recomplete additional wells and acquire more geologic and geophysical data. Vermilion holds some 176,000 net acres and has applied for more than 600,000 acres in permits in the Paris Basin.

Next off the blocks will be the much-anticipated Toreador Resources/Hess Corp. test on the Chateau Thierry permit, east of Paris. The partners, based in Paris and New York City, respectively, are poised to spud their first test (a vertical well) momentarily.

The companies teamed up in May 2010 when Hess Corp. paid Toreador $15 million for interests in Toreador's Paris Basin holdings. Hess also agreed to invest up to $120 million in the properties, including the drilling of six exploration wells.

The deal covers 680,000 net acres awarded to date; each company has the right to 50% of the net acreage. They have requests pending with the French government for another 880,000 gross acres.

Likewise, Vancouver-based Realm Energy International Corp. has applied for 1.6 million acres in the Paris Basin. "Nothing is cut in stone; it's still a very competitive situation," says Mike Mullen, chief operating officer.

France awards permits based on work commitments on nominated blocks. The first mover does not necessarily get an advantage, notes Mullen, and promising blocks can have multiple pending applications.

"The competition period has pretty much ended, and now it's up to the government to dole out the awards, which we expect in the second quarter of 2011," he says.

While it awaits government disposition of the permits, Realm is continuing geologic studies, including in-depth reviews of existing well logs, mud logs, core and geochemical data. The company benefits from an ongoing relationship with Halliburton, in which the two collaborate on shale evaluation efforts.

"In addition to approaching the basin from the technical and environmental sides, we're also looking at the social impacts of shale development," says Mullen. "We want to find out the best way to work with the communities. We want to be good partners and good neighbors."

For France, which produces just 1% of the oil it consumes, a vibrant play in the Paris Basin that can be developed in harmony with its environmental values could be a wonderful advancement.