Completion technology has been a game-changer across the onshore U.S. in unconventional plays. “Completion technology has changed everything,” says Sylvia Barnes, managing director and head of energy investment banking for Madison Williams and Co. and a petroleum engineer. The application of longer laterals, a growing variety of fracturing fluids and proppants, and more frac stages are being tested daily.

Somewhat ironically, the sophisticated techniques refined in unconventional-gas plays are now having the greatest impact in oil situations. And, the ever-growing number of frac stages on Bakken wells won’t slow down until the incremental oil-production gains are no longer worth the increased cost and risk. No one sees that happening any time soon.

Brigham Exploration Co. has now applied 36 frac stages to a Bakken well, reporting that its Jack Cvancara 19-18 #1H in its Ross project area in Mountrail County, North Dakota, had a 24-hour peak flowback rate of 5,035 barrels of oil equivalent (4,357 barrels of oil and 4.07 million cubic feet of gas).

Just in early April, Brigham had established the highest-rate Bakken well, Sorenson 29-32 #1H. It had a rate of 5,133 BOE (4,335 barrels of oil and 4.79 million cubic feet of gas) earlier in the year. Brigham bases the ranking on public data of more than 2,700 Bakken wells.

It applied a 27-stage frac to Sorenson. The well made 52,500 BOE in its first 26 days of production, or some $3.7 million a day at, say, a $70 Nymex price per barrel, or an annualized rate of more than $44 million (if the production rate were unchanged).

Will a 50-stage frac job on a Bakken well yield yet more oil? Will a 60-stage job?

The difference in results from the Jack and Sorenson—approximately a mile apart—may be an indication of the threshold of frac stages versus production results in the play. Or it may not.

Bud Brigham, chairman, president and chief executive, says the company is not yet close to finding the point of diminishing returns in the play, as each frac stage is incrementally inexpensive. In some areas, it will push past 36 frac stages; in others, it is clear already that fewer fracs will be appropriate.

Reduced service costs have helped support engineers’ push. Brigham was applying seven-stage fracs to its Bakken wells at a finding and development cost (F&D) of $21 per BOE in 2007, in an $80 oil-price regime. In 2009, its 20-stage fracs contributed to F&D of $11 per BOE, as oil prices ranged from $30 to $80 that year and service costs plummeted.

Barnes, who recently discussed Bakken investment economics at an M&A program in Houston, says, “To date, in the Bakken, more frac stages have yielded more hydrocarbon initial production and EUR (estimated ultimate recovery). It’s yet unclear where we are going to reach diminishing returns on lateral lengths and number of frac stages. Under the supervision of good operators and capable drillers, we can expect to soon see if a 12,000-foot lateral could be improved by a 50-stage frac. I’m confident that engineers will be instinctively driven to keep pushing the envelope to the point…and will discover at what point the cost and risk of more frac stages fails to produce sufficient additional amounts of hydrocarbon.

“Will it hit a wall at 58 stages? I don’t think we’re there yet. I don’t think we’ve found the outer limit.”

Surface issues, rather than economics, could produce a boundary sooner, she adds. “At some length of lateral in many fields, we will run into lease-line issues.” And, increasingly aggressive fracturing may encounter interference with other wells.

Producing successful completions is somewhat of an art as well as a science. “It’s an on-the-job learning experience. You find out what works and what doesn’t work: slickwater or gel or acid or other fluid; ceramic, plain sand, resin-coated or other proppant.”

And, each unconventional-oil reservoir is different—from play to play, and even intra-play.

In the financial-partner regime, the point of diminishing returns to U.S. operators has also not yet been found, as Total AS, Statoil ASA and India’s Reliance Industries are among foreign operators that have signed up for school on the unconventional E&P business via joint-venture partnerships. And, the cost of entry being paid continues to be robust.