There appears to be an emerging resource play in East Texas that is centered on Woodbine fields in Brazon, Madison and Grimes counties. Several smaller companies have drilled horizontals into the Woodbine-Eagle Ford section and are showing the industry the play’s potential.
The Woodbine-Eagle Ford is of Upper Cretaceous age and lies above the Buda limestone and below the Austin Chalk. The Woodbine, the lower portion, is made up of sandstone and shale that are non-marine in the northern and central parts of the East Texas Basin and marine in the south and southwestern portion. The Eagle Ford overlies the Woodbine and consists of mostly marine, gray to dark-gray shale.
One of the active targets is the productive sands at Kurten Field, which is found in the upper part of the thick section of black marine shale of the Woodbine-Eagle Ford section, just below the Austin Chalk. Multiple sands have been identified in the area and the entire interval is estimated to be 800 feet thick. In addition, the Eagle Ford shale is also in the ear and appears to have several potential oil zones. The depth to the reservoirs ranges from 7,400 up to 9,400 feet. This information intrigues, both, East Texas mineral rights owners and operators in the area.
Historically, vertical wells with little fracture stimulation were used to extract oil and natural gas from the Woodbine fields. This method was initiated due to the oil production being from shallow depths and the reservoirs’ having high porosity and permeability. On the other hand, deeper targets, like the natural gas trends in Polk and Tyler counties, required more intense fracturing.
Throughout the 1970s and 1980s vertical Woodbine well completions were used in the Kurten Field. They had cumulative production ranging from 10,000 to 200,000 bbls or oil per well, with an average of about 37,000 bbls of oil per well. Similarly structured horizontal wells in the surrounding area have IPs from 250 to more than 1,000 bbls of oil per day with some natural gas and water. Estimated ultimate recoveries are thought to be between 350,000 to 500,000 bbls of oil.
The new horizontal wells have lateral lengths ranging from 5,000 to over 8,000 feet. These laterals take 20 to 38 stage fracture stimulation to complete. Thus far, reported wells costs, including drilling and completion, are between $4 – 6 million.
Chesapeake Energy Corp. and Devon Energy Corp. are two of the bigger companies that have started paying attention to the Eaglebine play. They have focused on Grimes, Madison and Walker counties. Energia Tejas LLC, Exterra energy Inc., Southern Bay Operating LLC, Crimson Energy Partners III LLC, PetroMax Operating Co. Inc and Sun resources NL have also leased mineral rights in East Texas to hold a stake in the play.
Toreador Resources Corp. currently has 80,000 gross acres in the East Texas Woodbine-Eagle Ford play with expected plans to amass an additional 20,000 acres in the near future. They plan to test several potential reservoir targets by drilling multiple wells in the Woodbine and Eagle Ford.
Gastar Exploration Ltd. has an estimated 19,400 net acres, with focus in Leon and Robertson counties. They are estimating well costs of $6 million with EURs of 140,000 to 400,000 boe. As of December 2011, they have drilled four wells in the Glen Rose and Eagle ford-Woodbine section that they are currently watching.
Madison, Brazos and Grimes counties have been the target of New Gulf energy LLC and their partner PertroMax. Together, they have drilled and completed 13 horizontal wells. their most recent laterals have exceeded 8,000 feet. Well IPs have been over 1,000 bbls of oil and 300 mcf per day.
Clayton Williams Energy Inc. has put together a large land position in Lee, Robertson and Burleson counties. Their primary target is the Austin chalk in Giddings Field, but the company has also drilled and is producing from four Eagle Ford wells in Lee and Burleson Counties. Their laterals are between 4,800 to 5,500 feet with 9 to 15 stage fracs. They estimate their well costs to be between $3.1 to $3.3 million.
(Data and information from Tim Pish, Scotia Waterous via OilandGasInvestor.com)