Oil is the engine driving unconventional explorers these days. In an investment forum at the Rocky Mountain Energy Epicenter 2011, put on in Denver in early August by the Colorado Oil & Gas Association, presenters talked about the oil-resource plays that are clicking on all cylinders.

Speakers touted the Montney, Niobrara and Spraberry/Wolfberry plays, depending on their unique acreage positions, joint-venture arrangements and results to date. But the one play unanimously selected by the group was South Texas' Eagle Ford.

For J. Bradley Fisher, vice president and chief operating officer of Houston-based Carrizo Oil & Gas Inc., the Eagle Ford carries less risk than the Niobrara, another play it works.

Carrizo's Eagle Ford reserves are about 80% liquids, and it figures an average well will recover 400,000 barrels of oil equivalent (BOE) and cost $7- to $8 million. Currently, the company runs three rigs on its 33,000 net acres. It has drilled 15 wells so far and has five wells on line that are testing at rates between 700 and 1,000 BOE per day.

"We really like the economics of the gas/condensate window," he says. "Production rates are strong, and we produce half the reserves out of the well within two years of starting production."

Panelist Jim Fraser, senior vice president, eastern region, for Talisman Energy Inc., noted Talisman is also a fan. For the Calgary-based firm, the Eagle Ford ranks with the Montney and Marcellus as its top three resource plays.

"We see the Eagle Ford as the most economic play. It works at $1.50 to $2 per Mcf breakeven, obviously carried by the liquids," he said.

The company holds 78,000 net acres in the heart of the Eagle Ford's liquids-transition window. It built the position through a series of acquisitions during the past year, which culminated in a 50/50 joint venture with Statoil.

To date, the company has only a solo Eagle Ford well that came on at 1,300 BOE per day. But, many more wells will be turned to sales shortly: it has secured two dedicated stimulation crews and is now starting completions on a 16-well backlog of drilled holes.

"We are at the very early stages of optimizing our well completion design for the Eagle Ford," said Fraser. From one rig at work a year ago, Talisman plans to have 10 running at year-end.

Mega-independent Anadarko Petroleum Corp. built its position in the western uplift of the basin, where it saw all the favorable components of the Eagle Ford and Pearsall shales come together. "It's a shallow section that's liquids-rich, easily accessible and easy to drill," said Jim Kleckner, vice president, operations. Well results to date are impressive, with estimated ultimate recoveries standing at more than 450,000 BOE. The company plans to drill some 200 wells this year.

Anadarko has been able to strongly ramp up production by finding multiple solutions to the myriad problems that all operators face in rapidly evolving plays, according to Kleckner.

"By pulling the supply chain together, we've been able to reduce the time between spud to first sales to 40 to 45 days. It's an incredible accomplishment by our Eagle Ford team."

Finally, Scott Sheffield, chairman and chief executive, Pioneer Natural Resources Inc., said the Eagle Ford comes in second only to the Spraberry/Wolfberry of West Texas for his firm.

In the Eagle Ford play, Pioneer has 300,000 acres and a $1.35-billion JV with Indian firm Reliance Industries Ltd. "We were fortunate enough, sometimes by luck, to have the right acreage at the right time," he said.

Today, Pioneer holds 700 million BOE of net resource potential and more than 2,000 drilling locations in the Eagle Ford. It runs 12 rigs in the play and is adding another seven. The company also owns a frac crew and a coiled tubing unit in the Eagle Ford, and it plans to add a second of each later this year.

"It's amazing to me, in my career, as old as South Texas is, for a 25-billion-barrel discovery to be made in our backyard," said Sheffield.

For more on the Eagle Ford shale, see UGcenter.com.