They like it slick in the Permian Basin when it comes to fracture stimulation.

Slickwater has regained popularity in the basin after some operators reduced use of gels when production rates did not support the added expense.

“We had several clients revert back to straight slickwater fracks rather than gel, but they just keep increasing sand volume,” a mid-tier service provider told Hart Energy market intelligence surveyors in October 2014.

Permian operators are standardizing on completion practices following an extensive round of experimentation as the industry works through the optimization process in multiple tight oil formations. That said, operators are also citing growing use of coil-tubing fracture stimulation with newer generation sliding sleeves to enhance production.

“We have had many operators willing to try the coil frack with sleeves since some of the recent production reports show the value,” one coil tubing completion specialist told Hart Energy. “We have about five large operators running tests to compare coil frack and standard slickwater fracks in order to get good comparison numbers.”

Hart Energy market intelligence surveys revealed operators are employing stage spacing from 80 to 300 feet in the Permian. Standard slickwater fracks using plug and perf completions averaged 225 feet region-wide in the most recent survey. Stage spacing for sliding sleeves was tighter and averaged about 100 feet with operators substituting smaller stages using newer sleeves to replace longer stages and three perforation sets. The argument is that the newer sleeves provide pinpoint stimulation.

“For the most part, spacing is still very similar here,” one mid-tier service provider said. “But we are seeing longer laterals with growing sand volumes as a continuing trend.”

About three-fourths of survey participants cited plug and perf as the standard in completion techniques. There was a slight increase in the number of survey participants using sliding sleeves since the last Permian market canvass 90 days ago.

“We know that plug and perf is still the dominant method,” a completion services provider said. “However, we have very good data to show production results now. Four major operators now use sleeves only in their completions and five to six more majors are testing the methods against each other at present. It will be interesting to get the production data from the head-to-head comparisons.”

Pad drilled wells continue to grow in number. The average number of wells per pad grew to three in September vs. two in earlier surveys. Multi-well pad drilling varies across the Permian, depending on the maturity of development.

Zipper fracks represented 44% of horizontal completions in the current survey with the remainder as stacked fracks. Zipper-frack market penetration currently remains low due, in part, to a smaller percentage of multi-well pads vs. markets like the Bakken or Eagle Ford that have advanced to the resource harvest phase of tight formation development. Coiled tubing fracture stimulation is performed one well at a time.

As is common elsewhere, sand use per well is rising. The average among respondents was 5 million pounds per well, mostly involving 40/70 and 20/40 grades with some 100-mesh. Sand volume is almost twice the 2.75 million pounds reported previously for the Permian Basin. No respondents in the present survey reported using ceramic proppant.

Pressure pumping capacity is expanding to meet increased demand for services as operators switch to longer laterals and the number of horizontal completions rises. Additionally, demand for multi-stage fracturing in stacked vertical plays remains stout. Survey participants estimated regional capacity had expanded to 2.9 million hydraulic horsepower (HHP).

“We added two new fleets and still can’t take much spot work as the new fleets were dedicated immediately,” a top tier service provider said. “Our competition is adding fleets, too.”

In general, a typical Permian horizontal well involves vertical depth of 8,500 feet with a 6,600-foot lateral and an average of 35 stages placed roughly 200 feet apart. Average injection rates are reported at 65 barrels per minute with five stages completed daily on a 24-hour schedule with plug and perf and 11 stages per day with sliding sleeves.

Data for the Bone Spring shows average vertical depth of 9,000 feet with horizontal laterals averaging 4,500 feet. Stage count was listed at 20 on average with well stimulation providers completing an average four stages per day on a 24-hour schedule. Injection rates were reported at 70 barrels per minute for the Bone Spring.

The Permian Basin features lower average per stage costs because of widespread geological diversity and a greater mix of vertical multi-stage fracturing. Additionally, sliding sleeves were listed as less expensive. Average stage costs came out to $66,000, though standard plug and perf averaged $80,000 per stage.

“There are wide swings when pricing by the stage as sleeve jobs have almost three times more stages [but much smaller stages] than the standard job,” a mid-tier service provider said. “Price can be $35,000 per stage for sleeves, or $100,000 per stage for big high-sand volume plug and perf jobs.”

All survey respondents expect pricing to increase over the next 90 days.

“These frack pumps haven’t gotten any cheaper,” a mid-sized service provider said.

Contact the author, Richard Mason, at rmason@hartenergy.com.