A test of what may be the Pearsall Shale’s elusive oil-rich window in Frio County, Texas, is a gusher, according to an IP report just filed with the Texas Railroad Commission (RRC).

Privately held Formentera Partners reported its Hurrikain Cat I-STX #S731H came in with a 24-hour IP of 1,499 bbl from the Pearsall trend’s Lower Bexar member at about 10,000 ft.

Drilled in Frio’s southeastern corner, the 7,862-ft lateral made 4 MMcf of associated gas as well, according to the report filed April 14.

The IP per 1,000 lateral feet was 191 bbl. Choke size was 36/64. Gravity is 44 degrees.

The well had already produced 15,130 bbl by Feb. 3, the day of the 24-hour IP test, according to the RRC file.

Austin, Texas-based Formentera did not reply to Hart Energy’s request for comment by press time.

Bryan Sheffield, managing partner, told Hart Energy this past autumn, though, that Formentera’s plan was to use modern frac recipes and longer laterals in the Pearsall, while past wildcatting for economic Pearsall oil pay was done with short laterals and the lower-intensity frac formulas of the time.

Also, Formentera’s focus is updip of where Pearsall wildcatting in the early 2010s met primarily with gas.

An initial indicator of the Hurrikain’s success was that the operator filed the IP report as a W-2, which is the RRC form for an oil well, rather than as a G-1, which is for a gas well and more typical from the Indio Tanks-Pearsall Field.

There, the Pearsall sits at about 3,000 ft deeper than the Eagle Ford, which is lightly drilled in the area in contrast to neighboring counties where operators make economic Eagle Ford pay.

EOG Resources’ test

The Hurrikain lateral travels along Highway 1582 near its intersection with Highway 85 in southeastern Frio, surrounded by short-lateral Austin Chalk wells at about 6,500 ft that were drilled pre-2000 and have since been plugged.

Its lateral path is southeasterly from the same pad as Formentera partner Britanco LLC’s northwesterly Darlene 1-STX #N731HP test of the Pearsall last summer.

Formentera reported on Darlene in an incomplete W-2 last October as a shut-in producer. The report noted it was a pilot hole from Pearsall to Sligo. It was plugged back at Pearsall below Glen Rose.

EOG Resources drilled a Pearsall wildcat last summer about 15 miles southwest of the Hurrikain pad. It filed an incomplete G-1 on March 24 for the well, Burns Ranch #1H, describing it as a shut-in producer.

The report showed Pearsall is at about 11,000 feet at the well’s location.

More pounds/ft

Pearsall tests map
Formentera Resources’ Pearsall test, Hurrikain Cat I-STX, is in southeastern Frio County, while EOG Resources has put a Pearsall test, Burns Ranch #1H, in south-central Frio. (Source: Hart Energy via Texas Railroad Commission GIS viewer)

Wildcatters IP’ed liquids from Pearsall horizontals in the early 2010s. But the EURs proved uneconomic, resulting in the formation being dubbed a “heartbreak shale.”

A Marathon Oil well, Whitley-Dubose #1H, which is now owned by Britanco within what is now the Formentera-Britanco property, made about 100,000 bbl in 10 years.

But its 5,736-ft lateral was completed with 16 bbl/ft of fluid and 475 lb of proppant/ft in 20 stages, Sheffield said.

“If we go to 2,000 and 3,000 pounds per foot, you know that well is going to IP north of 400 bbl/d,” he expected at the time.

Rob Turnham, who was president of longtime South Texas wildcatter Goodrich Petroleum, told Hart Energy after reviewing the completion report, “All of this looks like a very good well to me. You just have to watch it over time.”

That Formentera did the IP test on a 36/64 choke, which is typical for an Eagle Ford oil well in South Texas, is a good look at what the rock will do, he added, rather than an IP report on a severe choke.

The well already flowing for 14 days prior to the IP test also gives insight. “It’s not just one day at peak rate,” Turnham said.

And, frac recipes have evolved. With making hole in South Texas’ many layers of pay over decades, it was inevitable the Pearsall would make a well this size, he said.

“It makes sense someone would come in and put a modern-day frac on it.”

That Formentera and EOG are wildcatting the formation is encouraging as well, he said.

“You have companies in here who know what they’re doing.”