The Barnett shale in north-central Texas lies in the Fort Worth Basin. Discovered in the 1950s, the Barnett was not commercially viable until the 1980s. Some geologists believe the formation could hold 30 TCF of natural gas. A significant part of the drilling has occurred in the Fort Worth metro area, and Chesapeake Energy actually secured rights to drill beneath the Dallas-Fort Worth International Airport. Drilling in the Barnett shale intensified in the past decade as modern horizontal drilling and hydraulic fracturing techniques were perfected for drilling in shale. Devon Energy, Chesapeake Energy, XTO Energy, and EOG Resources are among the larger players in the Barnett shale. Two years ago, 70% of all US gas shale production came from the Barnett, but that percentage of the total has been declining as production has risen in other plays.
The Fayetteville shale is located on the Arkansas side of the Arkoma Basin and cuts a swath through the north-central part of the state east to the Mississippi River. The Fayetteville shale play could hold 15-20 TCF of natural gas. Chesapeake Energy is the second-largest lease holder in the Fayetteville shale play, followed by Petrohawk Operating Co. and XTO Energy, which was recently acquired by Exxon Mobil. Southwestern Energy of Houston was first to enter the Fayetteville shale play and today still has nearly three times the natural gas production of its nearest competitor in the formation. Southwestern has sold some of its Fayetteville assets to XTO Energy.
The Bakken shale is primarily an oil play. Located in the Williston Basin, however not all of the basin includes the Bakken Shale. The play runs through Montana and North Dakota , as well as Saskatchewanand Manitoba provinces in Canada. Reserves estimates are in the range of 3.5 to 4.0 billion barrels (Bbo) of recoverable crude oil in the Bakken, which would make it a very large oil field in the US outside of Alaska. The Sanish-Three Forks area is located below the Bakken shale zone and is potentially another new oil reservoir. Brigham Exploration Company has been active in this area. Natural gas is also found in some parts of the Bakken. Reserve estimates range from 1.8 to 2.0 TCF of gas and another 150 MMB of natural gas liquids. Major players in the Bakken include EOG Resources, Continental Resources, GeoResources Inc., Resolute Energy Corporation, ONEOK Partners LP and EnerPlus Resources.
The Haynesville shale play runs through North Louisiana, North Texas, and Southern Arkansas. Some industry experts believe the Haynesville shale could ultimately produce 30 to 40 TCF of natural gas andwill out produce the Barnett shale in less than five years. The reason is the formation is thick and also very thick at higher reservoir pressure. The depth and high pressures make drilling expensive, but the payout is believed to be worth the cost. Chesapeake Energy is the major acreage holder and gas producer in the Haynesville, other smaller operators, including Houston-based PetroHawk Energy, haveacquired significant positions and are increasing production quickly.
The Marcellus Shale play runs 600 miles North-South through northern Appalachia, primarily in the states of Pennsylvania, West Virginia, New York, and Ohio. It is part of the Devonian Black Shale and thethickness of the gas-producing rock is as much as 900 feet. Reserve estimates are in the 45 to 50 TCF range which makes it the biggest gas field in the US North America. The location near the Eastern US urban areas makes the Marcellus so desirable. Range Resources was one of the early players in the Marcellus and still has a huge position in the play. Statoil of Norway has signed a joint venture with Chesapeake Energy to work together in the Marcellus. Many other energy companies including Fortuna, Chief Oil & Gas, Cabot Oil & Gas and, EQT Energy are also engaged in this play.
The Woodford shale play is located in Oklahoma and has been under development during the last 10 years. Devon Energy drilled the first well into the Woodford shale formation in 2005, and since then numerous petroleum companies have acquired acreage and launched their own drilling programs. Current estimates are that the Woodford shale holds approximately 4 TCF of natural gas. Other players include Newfield Exploration of Houston and Devon of Oklahoma City which are the largest gas producers in the play.
The Cotton Valley subsurface formation is a tight gas play in North Texas and North Louisiana located just above the Haynesville/Bossier Shale. It is Upper Jurassic and Lower Cretaceous in origin and consists of sandstone, limestone, and shale. The depth of the Cotton Valley formation is roughly 7,800 to 10,000 feet. Although it is mainly a natural gas play, some oil has been produced in parts of the Cotton Valley. Some of the more active players are Petrohawk Energy, Goodrich Petroleum, Exco Resources, Forest Oil, XTO Energy (ExxonMobil), Questar, Penn Virginia, Cabot Oil & Gas, Devon Energy, and El Paso Corporation.
Eagle Ford Shale
The Eagle Ford shale formation is situated in South Texas runs from Laredo to Houston. It is located directly below the Austin Chalk. The Eagle Ford produces both natural gas and oil, but it is the oil-producing and gas condensate areas that is active at this time. Average thickness is about 500 feet. The more active part of the region is mainly in McMullen, Maverick, Dimmit, La Salle, Karnes, Live Oak, andAtascosa counties. Apache Corp. and EOG Resources are two of the largest lease-holders. Other major players include Petrohawk, Swift Energy, ExxonMobil, ConocoPhillips, Murphy Oil, Chesapeake, Cabot Oil & Gas, and Pioneer Natural Resources.
The Midcontinent Granite Wash is a series of tight gas plays (Lard Ranch, Buffalo Wallow, Stiles Ranch, and Colony West) that extend along North Texas and South Oklahoma. There is some oil production in the Granite Wash, mainly in Oldham and Gray counties in Texas. The reservoir is about 160 miles long and 30 miles wide. Both horizontal and vertical drilling is underway to develop reserves from this long time target. Economic flow rates are achieved by multi-stage, slickwater fracture treatments and close attention to costs. There are over 2600 operating wells in the Granite Wash. The most active operators are Chesapeake Energy, Newfield Exploration, Penn Virginia, Cimarex Energy, Questar, Linn Energy, Forest Oil, Apache Corp., BNK Petroleum, Devon Energy, and Cordillera Energy Partners.
The emerging Niobrara Shale formation is situated in the Denver-Julesburg Basin in North Colorado,South Wyoming, Nebraska, and Kansas. As a new play it is in the early stages of development and companies have been busy leasing land for future drilling. It has been compared by some to the Bakken shale formation in the Williston Basin. Samson Oil & Gas is one of the earliest companies to establish a position in the Niobrara, Other operators include EOG Resources, Anadarko Petroleum, SM Energy, Noble Energy, Chesapeake Energy, Whiting Petroleum, Quicksilver Resources, MDU Resources, and Bill Barrett Corporation.
The Utica shale formation is located in North New York State and also in Canada (Quebec). The play could extend as far south as Pennsylvania and overlap with the Marcellus shale. Reserve estimates range from about 5 to 60 TCF. Most of the activity is taking place in Canada as the state of New York has been reluctant to grant drilling permits to date. Some production rates have tested up to 1 million cubic feet perday.
The Piceance and Uinta basins are situated in North Utah and North Colorado. Both the Piceance and Uinta are tight sandstone gas resources plays. The primary target of gas development has been the Cretaceous Williams Fork formation. The Williams Fork is a several-thousand-foot thick section of shale, sandstone, and coal deposited in a coastal plain environment. The low permeability sandstone reservoirs and limited areal extent of the reservoirs has made conventional gas wells uneconomic in the past. Major players include Chevron, Encana, ExxonMobil, Noble Energy, Bill Barrett Corporation, Antero Resources, Delta Petroleum, Laramie Energy, and Harvest Natural Resources.
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