The Wattenberg Gas Field is a large producing area of natural gas and condensate in the Denver Basin of central Colorado, USA. Discovered in 1970, the field was one of the first places where massive hydraulic fracturing was performed routinely and successfully on thousands of wells. The field now covers more than 2,000 square miles between the cities of Denver and Greeley, and includes more than 23,000 wells producing from a number of Cretaceous formations. The bulk of the field is in Weld County, but it extends into Adams, Boulder, Broomfield, Denver, and Larimer Counties.
The reservoir rocks are Cretaceous sandstones, shales, and limestones deposited under marine conditions in the Western Interior Seaway.
The gas and condensate is contained within Cretaceous formations in the deepest part of the Denver Basin, where the rocks were subject to enough heat and pressure to generate oil and gas from organic material in the rock. The field is a stratigraphic trap, basin-centered gas field. Most of the gas-producing formations are considered tight gas, having low natural permeability. Although the field today is in the deepest part of the basin, an unconformity at the base of the Pierre Shale shows that the field is on an early paleohigh active in the Middle Cretaceous. [1]
Although numerous wells had drilled through the Wattenberg Field over the decades, and many drillers and wellsite geologists noticed gas “shows” (indications) in the "J" Sandstone and other strata, the "J" Sandstone and other gas-bearing formations had permeability too low to yield gas in commercial quantities. Core samples indicated the "J" Sandstone was similar to the Lower Cretaceous Dakota Sandstone reservoir in the San Juan Basin. This was supported with the Aug. 1967 discovery of the Roundup Field. Additionally, examination of outcrops and electrical logs showed the "J" Sandstone to be a delta-front sandstone. [2]
Amoco geologist Pete Matuszczak noticed that all the wells drilled over a large area recorded noncommercial gas shows, with no water, through the "J" Sandsone (also called the Muddy Sandstone) on the mudlogs, cores, and drillstem tests. He suggested that the area might be made to produce large economic quantities if the wells were treated with the new method of massive hydraulic fracturing, which Amoco was using successfully in the San Juan Basin of New Mexico. [3]
Drilling started in 1970, and wells were completed in the J Sandstone, at depths from 7350 to 8500 feet. Drilling deep gas also fortuitously found conventional oil in places in the shallower Terry and Hygiene sandstones. [4] The D Sandstone, another conventional reservoir, also produces in limited areas within Wattenberg.
Additional producing formations were added to the field. Starting in 1981, operators discovered that the Codell Sandstone would yield economic quantities of oil and gas if hydraulically fractured. Hundreds of new wells were drilled and completed in the Codell in the early 1980s; the Codell was often co-completed with the overlying Niobrara Formation. Additional wells were drilled and hydraulically fractured in the Plainview and Lytle formations, below the J Sandstone.
The initial spacing of one "J" Sandstone well per 320 acres was found insufficient to drain the reservoir, so the Colorado Oil and Gas Conservation Commission approved infill wells.
Gas wells in Wattenberg were drilled vertically until 2009, when operators discovered that horizontal wells drilled in the chalk of the Niobrara Formation yielded better quantities of gas and condensate, setting off a new round of drilling. [5]
In 1973, the field was thought to contain 1.1 trillion cubic feet of recoverable gas. Through 2008, the Wattenberg Field had produced 2.8 trillion cubic feet of gas, [6] and an estimated 5.2 trillion cubic feet of recoverable gas remained. [7] In 2013, the US Energy Information Administration listed Wattenberg as the 9th largest gas field in the US in terms of remaining proved gas reserves, 4th in remaining proved oil/condensate reserves. [8] As of March 2018, the field was producing 1.92 billion cubic feet of gas and 331 thousand barrels of oil and condensate per day, from more than 23,000 active wells. [9]
More than 40 companies operate wells in Wattenberg. As of 2017 [update] , the five largest producers of oil and gas in the field were: Kerr-McGee, Noble Energy, PDC Energy, Extraction Oil and Gas, and SRC Energy. Together, the top five producing companies produced 84 percent of the total gas produced in 2017. [10]
Coalbed methane, coalbed gas, or coal seam gas (CSG) is a form of natural gas extracted from coal beds. In recent decades it has become an important source of energy in United States, Canada, Australia, and other countries.
The Denver Basin, variously referred to as the Julesburg Basin, Denver-Julesburg Basin, or the D-J Basin, is a geologic structural basin centered in eastern Colorado in the United States, but extending into southeast Wyoming, western Nebraska, and western Kansas. It underlies the Denver-Aurora Metropolitan Area on the eastern side of the Rocky Mountains.
The Barnett Shale is a geological formation located in the Bend Arch-Fort Worth Basin. It consists of sedimentary rocks dating from the Mississippian period in Texas. The formation underlies the city of Fort Worth and underlies 5,000 mi² (13,000 km²) and at least 17 counties.
The Western Canadian Sedimentary Basin (WCSB) underlies 1.4 million square kilometres (540,000 sq mi) of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. This vast sedimentary basin consists of a massive wedge of sedimentary rock extending from the Rocky Mountains in the west to the Canadian Shield in the east. This wedge is about 6 kilometres (3.7 mi) thick under the Rocky Mountains, but thins to zero at its eastern margins. The WCSB contains one of the world's largest reserves of petroleum and natural gas and supplies much of the North American market, producing more than 450 million cubic metres per day of gas in 2000. It also has huge reserves of coal. Of the provinces and territories within the WCSB, Alberta has most of the oil and gas reserves and almost all of the oil sands.
The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah and Arizona. Specifically, the basin occupies space in the San Juan, Rio Arriba, Sandoval, and McKinley counties in New Mexico, and La Plata and Archuleta counties in Colorado. The basin extends roughly 100 miles (160 km) N-S and 90 miles (140 km) E-W.
The Piceance Basin is a geologic structural basin in northwestern Colorado, in the United States. It includes geologic formations from Cambrian to Holocene in age, but the thickest section is made up of rocks from the Cretaceous Period. The basin contains reserves of coal, natural gas, and oil shale. The name likely derives from the Shoshoni word /piasonittsi/ meaning “tall grass”.
The Bakken Formation is a rock unit from the Late Devonian to Early Mississippian age occupying about 200,000 square miles (520,000 km2) of the subsurface of the Williston Basin, underlying parts of Montana, North Dakota, Saskatchewan and Manitoba. The formation was initially described by geologist J. W. Nordquist in 1953. The formation is entirely in the subsurface, and has no surface outcrop. It is named after Henry O. Bakken (1901–1982), a farmer in Tioga, North Dakota, who owned the land where the formation was initially discovered while drilling for oil.
The Bend Arch–Fort Worth Basin Province is a major petroleum producing geological system which is primarily located in North Central Texas and southwestern Oklahoma. It is officially designated by the United States Geological Survey (USGS) as Province 045 and classified as the Barnett-Paleozoic Total Petroleum System (TPS).
The Haynesville Shale is an informal, popular name for a Jurassic Period rock formation that underlies large parts of southwestern Arkansas, northwest Louisiana, and East Texas. It lies at depths of 10,500 to 13,000 feet below the land’s surface. It is part of a large rock formation which is known by geologists as the Haynesville Formation. The Haynesville Shale underlies an area of about 9,000 square miles and averages about 200 to 300 feet thick. The Haynesville Shale is overlain by sandstone of the Cotton Valley Group and underlain by limestone of the Smackover Formation.
The Montney Formation is a stratigraphical unit of Lower Triassic age in the Western Canadian Sedimentary Basin in British Columbia and Alberta.
The Cardium Formation is a stratigraphic unit of Late Cretaceous age in the Western Canada Sedimentary Basin. It takes the name from the fossilized heart-shaped cockle shells in the family Cardiidae present. It was first described along the Bow River banks by James Hector in 1895. It is present throughout western Alberta and in northeastern British Columbia, and it is a major source of petroleum and natural gas.
The Spraberry Trend is a large oil field in the Permian Basin of West Texas, covering large parts of six counties, and having a total area of approximately 2,500 square miles (6,500 km2). It is named for Abner Spraberry, the Dawson County farmer who owned the land containing the 1943 discovery well. The Spraberry Trend is itself part of a larger oil-producing region known as the Spraberry-Dean Play, within the Midland Basin. Discovery and development of the field began the postwar economic boom in the nearby city of Midland in the early 1950s. The oil in the Spraberry, however, proved difficult to recover. After about three years of enthusiastic drilling, during which most of the initially promising wells showed precipitous and mysterious production declines, the area was dubbed "the world's largest unrecoverable oil reserve."
Shale gas in the United States is an available source of unconventional natural gas. Led by new applications of hydraulic fracturing technology and horizontal drilling, development of new sources of shale gas has offset declines in production from conventional gas reservoirs, and has led to major increases in reserves of U.S. natural gas. Largely due to shale gas discoveries, estimated reserves of natural gas in the United States in 2008 were 35% higher than in 2006.
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Tight gas is commonly used to refer to natural gas produced from reservoir rocks with such low permeability that massive hydraulic fracturing is necessary to produce the well at economic rates. The gas is sealed in very impermeable and hard rocks, making their formation "tight". These impermeable reservoirs which produce dry natural gas are also called "Tight Sand".
Fracking is a well stimulation technique involving the fracturing of formations in bedrock by a pressurized liquid. The process involves the high-pressure injection of "fracking fluid" into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely. When the hydraulic pressure is removed from the well, small grains of hydraulic fracturing proppants hold the fractures open.
The Parshall Oil Field is an oil field producing from the Bakken Formation and Three Forks Formation near the town of Parshall, in Mountrail County, North Dakota. The field is in the Williston Basin. The field was discovered in 2006 by Michael Johnson and sold the play to EOG Resources, which drilled, and now operates, most of the wells. It was the discovery of the Parshall Field that was largely responsible for the North Dakota oil boom. Parshall's break-even price is at US$38/barrel, which is the lowest on the Bakken Formation; overall, Bakken's break-even point is of US$62/barrel.
The Marcellus natural gas trend is a large geographic area of prolific shale gas extraction from the Marcellus Shale or Marcellus Formation, of Devonian age, in the eastern United States. The shale play encompasses 104,000 square miles and stretches across Pennsylvania and West Virginia, and into eastern Ohio and western New York. In 2012, it was the largest source of natural gas in the United States, and production was still growing rapidly in 2013. The natural gas is trapped in low-permeability shale, and requires the well completion method of hydraulic fracturing to allow the gas to flow to the well bore. The surge in drilling activity in the Marcellus Shale since 2008 has generated both economic benefits and considerable controversy.
The Eagle Ford Group is a sedimentary rock formation deposited during the Cenomanian and Turonian ages of the Late Cretaceous over much of the modern-day state of Texas. The Eagle Ford is predominantly composed of organic matter-rich fossiliferous marine shales and marls with interbedded thin limestones. It derives its name from outcrops on the banks of the West Fork of the Trinity River near the old community of Eagle Ford, which is now a neighborhood within the city of Dallas. The Eagle Ford outcrop belt trends from the Oklahoma-Texas border southward to San Antonio, westward to the Rio Grande, Big Bend National Park, and the Quitman Mountains of West Texas. It also occurs in the subsurface of East Texas and South Texas, where it is the source rock for oil found in the Woodbine, Austin Chalk, and the Buda Limestone, and is produced unconventionally in South Texas and the "Eaglebine" play of East Texas. The Eagle Ford was one of the most actively drilled targets for unconventional oil and gas in the United States in 2010, but its output had dropped sharply by 2015. By the summer of 2016, Eagle Ford spending had dropped by two-thirds from $30 billion in 2014 to $10 billion, according to an analysis from the research firm Wood Mackenzie. This strike has been the hardest hit of any oil fields in the world. The spending was, however, expected to increase to $11.6 billion in 2017. A full recovery is not expected any time soon.
Fracking in Canada was first used in Alberta in 1953 to extract hydrocarbons from the giant Pembina oil field, the biggest conventional oil field in Alberta, which would have produced very little oil without fracturing. Since then, over 170,000 oil and gas wells have been fractured in Western Canada. Fracking is a process that stimulates natural gas or oil in wellbores to flow more easily by subjecting hydrocarbon reservoirs to pressure through the injection of fluids or gas at depth causing the rock to fracture or to widen existing cracks.