The Woodford shale is a deposit of Devonian age rock that is roughly 416 to 359 million years old. It is found under much of Oklahoma and as far west as the Marfa Basin in West Texas.
The Marfa area of West Texas is known for mystery lights that appear floating above the desert at night, for large ranches, art galleries and miles of untouched desert. The skies in this part of the Big Bend region are some of the darkest in the world, making it a good location for the McDonald observatory in nearby Fort Davis.
The movie Giant starring James Dean, was filmed just outside of Marfa and for years the facade of the home in the movie was visible from the highway. The irony is that in the movie, oil was discovered, making everyone rich, yet the county where Giant was filmed features little oil and gas activity. All of that might be about to change.
Residents who moved to the isolated region of West Texas might not have bargained for oil and gas drilling but it could be coming, like it or not. Under much of the Big Bend lies the Woodford shale, a potential source of natural gas.
The Woodford shale play in the Marfa Basin is yet one of many hot shale gas exploration plays around the United States. With horizontal drilling methods it is now possible to extract natural gas from shales like the Woodford, Barnett shale, Marcellus shale and others. There is plenty of natural gas now thanks to these discoveries. The world might be running short of oil but it is brimming with reserves of shale gas that are mostly yet untouched. In the Marfa basin, which holds Woodford shale of the same age as the larger deposit in Oklahoma, companies like Continental Resources have leased acreage for exploration.
As seen in this map of the Woodford Shale and Barnett shale in West Texas covers a broad area.
Continental Resources has a 50% working interest in partnership with TXCO Resources, in leases of totaling 135,000 acres in Brewster and Presidio counties. In 2006 they re-entered an existing well and tested the shale for productivity. The quantities of gas obtained were non-commercial but this does not indicate what may be present elsewhere in the Marfa Basin. Here the Woodford shale and Barnett shale equivalents are over six hundred feet thick and thermally mature.
The interest in the Woodford shale in the Marfa Basin has been reduced somewhat by the depressed price of natural gas. With so many shale gas wells producing the price of natural gas has been on a downward trend for the past few years. Companies are focusing capital on projects that also yield oil and condensate, such as the Eagle Ford Shale in South Texas.
Things have been fairly quiet in the Marfa basin since the initial test of the Woodford shale in 2006.
Still the Woodford shale in Presidio and Brewster counties will be the subject of future exploration. There are many signs that it can be an economically viable source of natural gas. It has depth, thermal maturity and high organic content. These three are what geologists look for when exploring for shale gas.
Residents may have a while to enjoy the pristine Texas wilderness before drilling rigs arrive in great numbers. A number of things will make this one of the last shale gas plays to be developed, if in fact it is determined to be economically viable.
One drawback to drilling for oil and gas in the Big Bend region of West Texas is the lack of water. New wells require water to drill and thousands of gallons of water for hydraulic fracturing of the shale once the well is completed. Waters is as scarce as hens teeth in this part of the nation.
Another factor is that this area of the state is not known for oil and gas production and lacks any kind of infrastructure for major drilling and production. The network of gas pipelines is not well developed and it wold cost millions to extend lines to the area for what could be a marginal shale gas play.