The East Texas Basin Woodbine sands have been a long-time target of conventional oil producers, but down in Madison and surrounding counties, below the Angelina-Caldwell flexure, the unconforming sandstone interlaced with shale is significantly tighter and harder to produce than the historically prolific fields to the northeast.

But bring modern unconventional technology to bear. Led by private independents, companies are revisiting these conventional Woodbine fields near historic production and are experiencing initial production (IP) rates ranging from 500 to 1,500 barrels of oil equivalent (BOE) per day in certain areas.

Recently, operators have begun exploring deeper into the more shale-like rock, which is contiguous across the basin, with promising but varied results. The Eagle Ford shale, a star productive zone in South Texas, is present here.

The East Texas Woodbine-Eagle Ford is, in fact, three emerging unconventional resource plays, with multiple oil-bearing targets adding to its appeal. In addition to the Woodbine sandstone and the Eagle Ford shale, a host of oil-bearing targets exists in the Lower Cretaceous formations.

Halcón Resources Corp. is the most active operator in the play with six rigs on the ground, targeting two of the intervals. Halcón president Steve Herod says the resource here is a pillar of the company’s growth plans.

Crimson Exploration Inc. chief executive and president Allan Keel is another satisfied customer. “The economics here are very, very good,” he says.

Crimson’s sand-silt plays

With 85% of its total budget aimed at the Woodbine sands in southwestern Madison County and northern Grimes, you could say Crimson Exploration is confidently putting most of its drillbits in one basket.

Houston-based Crimson holds 19,000 net acres in three different areas of the play, about 6,000 acres each, of which more than half is a held-by-production legacy position. Its favorite and most active area, called Force, lies in western Madison County in Madisonville-West Field, and is offset by highly successful Woodbine Acquisition Corp. wells. Located in a field with historical vertical production, Crimson has drilled six wells here targeting Woodbine sands, with average 30-day IP rates of 900 BOE per day.

Crimson’s Force area is proving to be a sweet spot for the company. The latest two wells brought online illustrate the optimism. In early April, Nevell-Mosley #1H flowed at 1,164 BOE per day IP (1,021 barrels of oil, 77 barrels of gas liquids, 392,000 cubic feet of gas) from a 6,000-foot lateral with 22 fracture stages.

About two miles offset, Mosley B #1H, with the same length lateral and stages, flowed 1,143 BOE per day, and was holding above 1,000 daily barrels three weeks out.

But Keel confirms that the stratigraphy in the sands varies, and the Force sand pinches out across a ridge moving east. The company’s Chalktown area in this direction is prospective for a completely different Woodbine-age sand lens in the Lewisville formation. “It’s not homogenous.”

The Hawk

Barely a year and a half old, Houston-based Halcón Resources Corp. has compiled a 270,000-acre position in the East Texas Basin and high-graded two of its related plays as top priority for capex and development, right alongside its more mature Bakken program in importance. The reason? Large pools of easily accessible reserves can be turned into cash flow quickly.

In southern Leon County, after testing the edges to delineate the commercial boundaries, Halcón now considers its Halliday Field in the Woodbine sand play to be substantially derisked and proven.

Abundant vertical well control attracted Halcón, which acquired its position from privately held Fort Worth, Texas, companies Petromax Operating and CH4 Energy LLC, just a month after forming. The field had produced 2.2 million barrels of oil conventionally, about 50,000 barrels per well.

“We felt it was tight enough that you could come back in and exploit that with horizontal wells,” says Charles Cusack, executive vice president of exploration for Halcón.

But true to the varied nature of the Woodbine sandsilt, such rich deposits are contained within stratigraphic traps, and are not ubiquitous across a large geographic extent as are shale plays.

First-quarter results averaged 438 BOE per day after 30 days. The company has drilled 51 horizontal wells to date—14 in 2013—with 36 on production. The average lateral length for wells completed year-to-date is 6,700 feet.

With no expectation that every Woodbine sandstone acre in its portfolio will be equal, Halcón does anticipate finding other sweet spots across the play like Halliday.

In April, Halcón debuted El Halcón Field (“The Hawk”), a 50,000-acre play in northern Brazos County targeting the Eagle Ford shale at 9,000 feet subsurface.

Better than Eagle Ford

With its origins as a small, private start-up in the early days of the South Texas Eagle Ford shale, ZaZa Energy Corp., now a $200-million public company, is laying its bets on this East Texas play. The company was also a first mover in acreage acquisition here, having accrued some 140,000 gross acres concentrated in northwestern Walker County. ZaZa has since partnered with a large independent to help finance development of its position.

ZaZa has its own nomenclature for its targeted intervals, dubbed the “Eaglebine,” which is a combination of the Eagle Ford and Woodbine groups and represents strata from the base of the Austin chalk to the top of the Buda lime. This interval contains conventional formations interlaced with organic-rich source rock. At its thickest, the Eaglebine can exceed 1,000 feet in thickness.

Yet it’s the 150- to 250-foot section of silica-rich, laminated shale immediately above the Buda that has attracted ZaZa’s interest. ZaZa calls it the Lower Eaglebine. “Our Lower Eaglebine is Halcón’s El Halcón,” says ZaZa chief executive Todd Brooks, clarifying the terminology. “And it’s very oily.”