A liquids-rich play emerges from the tight Woodbine sands at the eastern edge of Texas's Eagle Ford shale.

A short time before the Eagle Ford shale play took flight, several companies had quietly set about writing a new chapter for the petroleum history books on what would become known as the Eaglebine play. For their efforts, the production numbers from wells drilled in the play are starting to show a significant return.

Geology of the play

Current activity in the Eaglebine is focused in Brazos, Grimes, Leon, Madison, Robertson, and Walker counties. The Eaglebine is the East Texas extension of the Eagle Ford. The name was coined to encompass both the Woodbine Group and the Eagle Ford Group. Bounded by the Austin Chalk and Buda limestone formations, the Eaglebine comprises conventional and unconventional reservoirs.

Formed during the Cretaceous period from fluvial flow deposition and marine sediments, the formation is widely spread across East Texas. The sands thicken between the San Marcos arch to the west and Sabine uplift to the east. The play is more shallow and oily to the northwest and becomes deeper and gassier to the southeast.

In remarks at the recent Hart Energy DUG Eagle Ford Conference, Thomas D. Bowman, vice president, Evaluation, Geology, and Geophysics for ZaZa, said that silica-rich sands and silts are intermixed in the entire Eaglebine section. The very thick interval contains more than 305 m (1,000 ft) of mixed-lithology sediments. Within the Eaglebine, there are two broad divisions: The upper Eaglebine has numerous sandstone packages interbedded with organic-rich shales, and the lower Eaglebine is more of a shale resource play. Additionally, deeper Lower Cretaceous targets such as Buda, Georgetown, Edwards, and Glen Rose exist in the area.

"With all of the different formations that operators have to choose from in this area, I expect to see plenty of growth," said Nicholas Hopkins, district engineer for Weatherford. "Operators are able to use one well site and drill multiple wells to multiple formations instead of multiple wells to a single formation."

Since 2007, about 100 horizontal wells targeting the Woodbine sands have been drilled. Through the application of technologies like horizontal drilling and hydraulic fracturing, producers are seeing success in the tight sands of the Eaglebine play. In remarks made at the Enercom Oil and Gas Conference in Denver in August, Floyd Wilson, chief executive of Halc?n Resources, said that horizontal drilling and modern completion techniques were the game-changer in the play.

Eaglebine producer roundup

Several companies, both large and small, are operating in the area. Here's a look at the activities of a few.

Crimson Exploration. Crimson Exploration has been actively developing the Woodbine in the 18,500 net acres the company holds in Madison and Grimes counties, which are divided into three areas: the Force, the Iola-Grimes, and the Chalktown. In an operations update, the company said that each area has "slightly different characteristics, including different sand lobes within the overall Woodbine section," significant in that it will require more than one well in each area to optimize production.

The company estimates that there are approximately 115 net potential drilling locations based on 160-acre well spacing, with a total net potential of more than 34 MMboe in the three areas.

In Crimson's Force area, located in Madison County, the company has approximately 5,750 net acres and has been operating there since early 2009. According to the company, there have been more than 50 wells completed in the Madisonville-West field (Force area) using modern horizontal drilling and fracture stimulation completion techniques.

Two wells of note in the Force area are the Mosley #1H and Payne #1H. As the company's first horizontal well in the Force area, the Mosley was spudded in January 2012. In its first four months of production, the well produced 128,000 boe.

The Payne well was completed and placed online in July. The well tested at a gross initial production rate of 1,332 boe/d on a 40/ 64 -in. choke and 328 psi of tubing pressure, the company said. The well was drilled to a total measured depth of 4,916 m (16,130 ft), including a 2,274-m (7,460-ft) lateral, and was completed using 26 stages of fracture stimulation.

Crimson's Iola-Grimes area, located in northwest Grimes County, covers approximately 7,650 net acres. A stratigraphically older Woodbine sand that is present in this area but not in the Force area is what caught the company's interest. The nearest offset horizontal well to produce from this Woodbine objective is approximately 1.6 km (1 mile) northwest of the A. Yates #1H and has produced 179,000 bbl of oil in 10 months.

The Yates #1H began production in July at a gross initial production rate of 472 boe/d. The well was drilled to a total measured depth of 4,670 m (15,320 ft), including a 1,849-m (6,065-ft) lateral, and was completed using 22 stages of fracture stimulation.

The company's Covington-Upchurch #1H well, also in the Iola-Grimes area, was drilled to a total measured depth of 4,642 m (15,228 ft), including a 1,582-m (5,190-ft) lateral. The company recently said that in preparation for completion operations it perforated the toe stage only of the lateral section, and during a 24-hr period the well produced naturally at a rate of approximately 6.9 MMcfe/d.

The well has yet to be fracture-stimulated, and the reported rate represents production from only one of the 15 planned perforation stages. The rate is, according to the company, anticipated to improve upon completion of fracture stimulation operations along the entire lateral. Additional capacity to handle the full gas volumes from this well are expected to be developed in the area by year-end.

The company's Chalktown area covers approximately 5,100 net acres in Madison County. This area tests the Lewisville Sand, a lower Woodbine objective that has produced from vertical wells in the immediate area. The Vick Trust #1H well was drilled to a total depth of 4,468 m (14,660 ft), including a 1,756-m (5,760-ft) lateral, and completed using 21 stages of fracture stimulation. Reported production rates of the well to date have been as high as 225 boe/d.

wells located in Robertson and Leon counties

Encana Oil and Gas has found success in its wells located in Robertson and Leon counties. (Image courtesy of Encana Oil and Gas USA)

Encana Oil and Gas USA. Encana Oil and Gas USA has leased 115,000 net acres in the play, with an estimated 8.6 Bboe of petroleum initially in place. The company said that it has drilled eight wells to date, with plans to drill and complete another six in the coming year. Out of the eight drilled, two wells of note are the Clyde Williams #2H and the Loraine McMurrey #1H.

The Clyde Williams #2H well, located in Robertson County, was drilled to total depth in 12 days and from spud to rig release in 16 days, making it one of the fastest wells drilled in the play, according to the company. Total depth of the well is 2,173 m (7,130 ft), including a 1,908-m (6,261-ft) lateral, and the well was completed in 21 stages. The reported average daily production from the well is approximately 198 boe/d.

The Loraine McMurrey #1H well, also located in Robertson County, was drilled to a total depth of 2,743 m (9,000 ft) and is reported by the company to have the longest lateral in the play at 2,545 m (8,349 ft) with a two-casing string program.

Halc?n Resources Corp. With approximately 200,000 net acres prospective for the Woodbine, Eagle Ford, or other formations leased or under contract in Leon, Madison, Grimes, and Polk counties, Halc?n Resources Corp. is the leader of the pack in terms of leased acreage in the Eaglebine.

According to Halc?n, its first Woodbine completion, the AM Easterling-Gresham A #1H well in Leon County, was drilled to a total depth of 4,348 m (14,265 ft), including a 2,051-m (6,730-ft) lateral, and completed with 24 stages. The reported initial gross production rate of the well was approximately 942 boe/d on a 32/ 64 -in. choke. Over the first 30 days, the average daily production from the well was approximately 706 boe/d.

In a recent 3Q 2012 operations outlook, the company said it has 15 horizontal wells producing, six wells being completed or waiting on completion, and five wells being drilled.

JBL Energy Partners. JBL Energy Partners has two different areas in the Woodbine play where it is actively involved. In June, the company said that it entered into a joint venture agreement with Terrace Energy LLC on one of its Woodbine prospects. Terrace acquired at 75% leasehold interest in approximately 13,500 acres. The first horizontal well on the prospect was spudded in August.

JBL Energy sold its interest in 17,000 acres in Leon County to Halc?n in August. Of that sale, Jason Lane, CEO of JBL Energy Partners, said, "JBL Energy Partners has over 10,000 acres in the Woodbine that we are currently mocking up a drilling program for, and [we] are using the funds from this sale to further develop multiple projects in both East Texas and the Gulf Coast region."

In October, the company and its partners, which include Furie Petroleum, Amerrill Energy, and Sun Resources NL, outlined a horizontal drilling program for a 3,800-acre prospect in Leon County. The program calls for drilling in 16 locations over the next two years with the first two wells scheduled to be spud in 1Q 2013. The company said that total reserves are estimated at roughly 7 MMbbl for the play.

ZaZa Energy. ZaZa Energy has a reported 90,000 net acres leased in the Eaglebine play. The company recently said that it has completed drilling and running production casing on its Stingray A-1H well in Walker County to a true vertical depth of 3,590 m (11,780 ft), and a 1,433-m (4,700-ft) lateral was drilled in the objective section. A pilot hole through the objective section was drilled with sidewall cores collected, and a full suite of logs was run, including a post-processed ELAN Shale Oil Evaluation (ELAN) for the empirical measurement of hydrocarbons in place. ZaZa said that the results from the technical evaluation of the well were "very encouraging, with the ELAN analysis estimating 21 Bcf and 29 [MMbbl of oil] per section in place." The company noted that estimates are preliminary and subject to revision. Initial production is planned to begin in late November 2012. The company said, based on initial information gathered from the well, it has entered into a multiwell rig contract with Nabors Drilling USA, plans to install production facilities, and has entered into a multiyear lease for a field office and yard in Walker County.

Regarding its operations, Todd A. Brooks, CEO of ZaZa, said, "The Eaglebine play is one of the most exciting emerging liquids-rich resource plays in the country, and the data we have in-house supports this sentiment."