EOG Resources Pulls Permit for Third Pearsall Shale Test

EOG Resources has pulled a permit for a third Pearsall shale test in South Texas that would take the potential oil window’s combined delineation with neighbor Formentera Partners to roughly 70 sq miles.

Derby West #1H is planned for about 5 miles southwest of where privately held Formentera plans two new Pearsall tests and about 8 miles west of Formentera’s first two tests, all in Frio County, according to new Texas Railroad Commission (RRC) data.

To date, Formentera has focused on southeastern Frio County where it believes it has mapped a Pearsall oil window updip of where the formation has typically produced gas.

In addition, it's expecting longer laterals and modern, high-intensity frac jobs on the rock to make the new play economic.

Meanwhile, EOG has focused on south-central Frio with intentions it has not yet made public.

It did not respond by press time to a Hart Energy request for comment on total land leased to date or findings from its shut-in Burns Ranch #1H, its most recent Pearsall test.

EOG’s newest Pearsall test, the Derby well, is a roughly 7-mile step-out from the Burns Ranch #1H, which EOG drilled and completed last summer but tight-holed it in RRC records, listing it as a “shut-in producer.” No IP or other data was provided.

EOG did list it with the RRC, though, as a gas, rather than oil, well.

Pearsall rights

The Early Cretaceous’ Pearsall is at about 10,000 ft, underlying the Late Cretaceous’ Eagle Ford at about 7,000 ft and the Austin Chalk at about 6,500 ft.

EOG’s Derby West #1H brings the total Pearsall-test well count to nine, consisting of two Formentera wells completed and online; two underway in May; two more permitted; one EOG well online in northwestern McMullen County; and one that is completed but shut-in.

The Derby will travel parallel to three Derby North horizontals Trinity Operating has not yet drilled, but pulled permits for in 2020 for up to 8,000 ft in the Briscoe Ranch-Eagle Ford Field.

In addition to the Eagle Ford, privately held Trinity operates in Oklahoma’s Arkoma Basin and in the Haynesville, totaling more than 5,000 wells and 2022 average daily production of 163,000 boe/d.

Meanwhile, EOG’s Burns Ranch #1H southwest of the planned Derby West well travels underneath Texas American Resources’ Eagle Ford producer, Burns Ranch T #132H, which is landed in the overlying Briscoe Ranch-Eagle Ford Field.

EOG’s lease has Pearsall rights where Texas American, the leading operator in the area, doesn’t, Troy Gieselman, Texas American’s senior vice president of land, told Hart Energy in its breaking-news report last summer about EOG’s Burns Ranch #1H plan.

Texas American has 9,000 acres with Pearsall rights adjacent to the EOG leasehold, though. “So we’re hoping they make a great well,” Gieselman said at the time.

Overlying the EOG leasehold, Texas American has rights to the base of the Buda immediately under the Eagle Ford.

‘Heartbreak shale’

Formentera’s two Pearsall wildcats that came online in January have produced 137,000 bbl of oil combined in their first 3.5 months online through April from a total of 3.24 miles of lateral, according to RRC data.

The wells’ production is 99.6% of all Indio Tanks-Pearsall Field oil output in 2025.

Known as the “heartbreak shale” in the past, Indio Tanks-Pearsall is Texas’ only Pearsall shale field.

It has made a total of 836,000 bbl of oil and 663,000 bbl of condensate since January 1993, the oldest date for which the RRC has on-demand digital production records.

The field’s first oil discovery—rather than condensate or gas—was made in 2012 by Cabot Oil & Gas, which is now part of Coterra Energy.

Formentera’s production beginning in January already represents 9% of the field’s total 1.5 MMbbl of liquids production since 1993.

Wells were drilled in the past in the field’s southerly gas window. It’s made 31 Bcf of gas and casinghead gas since 1993.

Four more Formentera wells

Since bringing its first two oily Pearsall wells online, Formentera is currently drilling two more—the Hooey-STX #N731H and Sendero-STX #S731H—which travel under a 1981-vintage, plugged, vertical Chalk well, Moore #1.

It plans another two-well pad—Roper STX #N731H and #S731H—which will travel under a 1982, plugged, vertical Austin Chalk well, W.W. McKinley #A-1.

The only other Pearsall oil well currently online in Frio County is the Whitley Dubose #1H that Marathon Oil made in 2014 and is now owned by Formentera’s Pearsall partner, Britanco LLC.

McMullen test

EOG’s first Indio Tanks-Pearsall test, Moonlight #22H, was in the northwestern corner of McMullen County, underneath one of its multi-well Eagleville-Eagle Ford 1 Field developments.

Brought online in April 2023, the Moonlight has produced 48,930 bbl of condensate and 859 MMcf of gas through this past April, according to the RRC.

First-month production averaged 361 bbl/d; April 2025 production averaged 25 bbl/d. Gas output declined from 2.9 MMcf/d to 685,000 cf/d.

The Pearsall’s best oil producer was BlackBrush Oil & Gas’ 2012-minted Pals Ranch #11H, which travels under its Pals Ranch #13H that is landed in the overlying Buda. The #11H produced 116,000 bbl of oil in its 28 months online.