Natural-gas fields

The principal source of helium is certain natural gas fields. The helium contents of more than 10,000 natural gases in various parts of the world have been measured (9). Helium concentrations of a few are Hsted in Table 2. In the United States, recovery of helium is economical only for helium-rich gases containing more than about 0.3 vol % belium. Most of the United States helium resources are located in the midcontinent and Rocky Mountain regions, and about 89% of the known United States supply is in the Hugoton field in Kansas, Oklahoma, and Texas the Keyes field in Oklahoma the Panhandle and Cliffside fields in Texas and the Riley Ridge area in Wyoming (11). 

In oil and natural gas fields and reservoirs, the boreholes are cased to stabilize the wells. Depending on the depth and the operating conditions, several pipes may be fitted inside each other in the area near the surface (telescope casing) (see Fig. 18-1). 

This is largely due to the discovery and development of major natural gas fields in the U.S. Southwest, mid-contment, on- and offshore areas of the Gulf of Mexico and Canada—and the development of safe and efficient interstate natural gas trans-missiou pipelines to transport natural gas to markets across the country. Some 77 percent at the natural gas consumers use is produced domestically. 

MacAvoy, P. W. (1962). Price Eoriiiatioii iii Natural Gas fields. New Haven, CT Yale University Press. 

Helium, the second element in the periodic table, has atomic number 2. This means its nucleus contains two protons and has a 2+ charge. The neutral atom, then, contains two electrons. There are two stable isotopes, helium-4 and helium-3, but the helium found in nature is almost pure helium-4. Helium is found in certain natural gas fields and is separated as a by-product. Sources of helium are rare and most of the world supply is produced in the United States, mainly in Texas and Kansas. 

In 1993 Russia had 48,000 kilometers of pipeline carrying crude oil, 15,000 kilometers for petroleum products, and 140,000 kilometers for natural gas. In recent decades, the natural gas lines have expanded at a much faster rate than the crude oil lines. The main natural gas pipeline, one of the Soviet Union s largest international trade projects, connects the natural gas fields of northern Siberia with most of the countries of Western Europe. Completed in 1984, the line passes nearly 4,000 kilometers across the Ural Mountains, the Volga River, and many other natural obstacles to connect Russian lines with the European system. 

One of the largest of the federal properties, the Elk Hills field in California, opened for production in 1976 and became the highest production oil and natural gas field in the lower 48 states at one point. In 1992, the field produced its one billionth barrel of oil. It was only the thirteenth field in U.S. history to reach this number and while managed by the DOE, Elk Hills generated over 17 billion in profits for the U.S. Treasury. 

For the calculations, it has been assumed that LPG is derived from natural gas processing. Natural gas is extracted from natural gas fields in the North Sea. The separated LPG is liquefied and transported via ship across a distance of 1000 km to the coast and distributed to filling stations via truck across an average distance of 500 km. 

Gas-to-liquids plants are generally located close to natural gas fields, as the transport costs for liquid fuels are less than those for gaseous fuels. The production of GTL is considered to be an alternative to liquefied natural gas (LNG), specifically when focusing on the end-product vehicle fuel and not the long distance transport of energy. In 1993, a first large-scale GTL plant was erected by Shell in Bintulu, Sarawak in Malaysia, based on Fischer-Tropsch synthesis. The plant s total thermal process efficiency is about 63% (Shell, 1995) (see Table 7.11) a second plant is under construction in Qatar, with production expected to begin in 2010. 

This group includes facilities engaged in exploration for, and operation of oil and natural gas fields. Activities include locating, drilling and completing wells, operation of separators, emulsion breakers and desilting equipment, and all other activities up to the point of... 

But in the natural-gas fields, where modern design techniques have been slow to penetrate, bubble-cap trays are still widely employed, to dehydrate and sweeten natural gas in remote locations. 

I used to reset relief valves on small-pressure vessels in the natural-gas fields in southern Texas. After adjusting the nut on the valve with a wrench, I would raise the vessel pressure to check whether the valve would relieve at the proper pressure. If not, I would continue to adjust the nut and, by trial and error, find the proper relief-valve setting. This is not a particularly practical method to adjust relief valves on stream on a process unit. It is also illegal to do so. 

The composition of natural gas varies with the source, but essentially is made up of methane, ethane, propane, and other paraffinic hydrocarbons, along with small amounts of hydrogen sulfide, carbon dioxide, nitrogen, and. in some deposits, helium. Natural gas is found underground at various depths and pressures, as well as in solution with crude-oil deposits. Principal gas deposits are found in the United States, Canada, the former Soviet Bloc, and the Middle East. The analysis of a gas sample taken from the Panhandle natural gas field in Texas is given in Table 1. Because numerous parts of the earth do not have natural gas at all, or where supply is less than demand, much natural gas is transported, notably by pipeline in the gaseous or liquid phase and across the seas in specially-designed LNG (liquefied natural gas) earners. 

TABLE 1. ANALYSIS OF NATURAL GAS FROM NATURAL GAS FIELD IN TEXAS PANHANDLE... 

Fig. 2. Location of principal natural gas fields in the lower 48 of the United States. Alaska, not shown, ranks third in terms of holding estimated reserves. iBatelle Memorial Institute i...

The consumption of natural gas gradually increased prior to World Wars I and II as more and more small pipelines bronghi commnnities within reach of natural gas fields accompanied by the retirement of previous manufactured or town gas facilities (the early forerunners of the substitute natural gas). 

To-be-developed processes C3+ hydrocarbons/methane NGL recovery from natural gas Field trials and demonstration system tests under way. Potential market is large... 

Elliot, T., Ballentine, C. X, O Nions, R. K., Ricchiuto, T. (1993) Carbon, helium, neon and argon isotopes in a Po Basin (northern Italy) natural gas field. Chem. Geol., 106, 429-40. 

Dehydrocyclodimerization of liquefied petrol gas (propane and butane) can be performed to yield BTX-aromatics (Table2, entry 21). Modified ZSM-5 based catalysts are used, for example in the UOP cyclar process [33], and the process will become attractive for extraction of aromatics from natural gas fields containing further C3-C4 fractions. 

Herring, W.O., Jenkins, R. "Standards Support and Environmental Impact Statement. An Investigation of the Best Systems of Emission Reduction for Sulphur Compounds from Crude Oil and Natural Gas Field Processing Plants", EPA Research Triangle Park, N.C.,... 

Small amounts of helium are extracted from the atmosphere by fractionation methods, but not commercially because of the small amount of helium in the atmosphere. A number of natural gas wells contain helium, which can be recovered by a liquefaction and stripping process. Natural gas containing at least 0.2 percent helium has been found in the American Southwest, where the natural gas fields are the major U.S. source of helium. Those helium-rich fields are within 250 miles of Amarillo, Texas other helium-bearing fields have been found in Saskatchewan, Canada, and in areas near the Black Sea. Helium cannot be synthesized so conservation and cleanup recycle systems for spent gas are important means of preserving the earth s helium resources. 

A similar situation also risks arising with the progressive production of the vast natural gas fields of eastern Canada. This development, whose effect is still slight today, could give rise in the future to a gradual shift of the production centers of basic petrochemical commodities. 

As is illustrated in the Figvure 1.6, ethane is the major feedstock of the region. Along with propane and butane, ethane is extracted from natural gas either as gas associated with oil or from large natural gas fields developed for LNG production, as in Qatar. 

A flare in a natural gas field is an example of a chemical reaction. 

CO2 may be able to be sequestered in geological formations, such as active and depleted oil and gas reservoirs, coalbeds, and deep saline aquifers. Such formations are widespread and have the potential to sequester large amounts of CO2 (Herzog et al., 2000). A model project is underway in the North Sea off the coast of Norway. The Sleipner offshore oil and natural gas field contains a gas mixture of natural gas and CO2 (9%). Because the Norwegian government taxes emissions of CO2... 

Estimates of the amount of recoverable oil and natural gas in the United States are 113 billion barrels of oil and 1,074 trillion cubic feet of natural gas. Worldwide estimates of recoverable oil and natural gas are 1 trillion barrels of oil and 5 quadrillion cubic feet of natural gas. These worldwide reserves are expected to supply 45 years of fuel at current production rates with expected increases in demand. However, such estimates do not take into account reserves added through new discoveries or through the development of new technology that would allow more oil and natural gas to be recovered from existing oil and natural gas fields. 

Conversion of natural gas to liquids is currently of great interest, as many large natural gas fields are not close enough to large markets to make construction of a pipeline economically attractive. These stranded reserves can be liquefied, converted into fuels or converted into (higher value) petrochemicals. U.S. 5,714,662 (to UOP) describes a process for converting crude methanol to olefins. What is the cost of production of the ethylene produced by a plant that produces 900 kmta of mixed olefins if the cost of producing the natural gas feed is 0.5/MMbtu ... 

Clapp, F.G. 1910. A proposed classification of petroleum and natural gas fields. Econ. Geol., 5 503-521. 

Many natural gas fields and gases coming from petroleum contain hydrogen sulphide. Moreover, in order to obtain cleaner gasolines for the environment, the use of hydrodesulphurization (Eq. 1) in modem refineries is increasing. These two factors could combine to triple the amount of sulfiir compounds and hence H2S to be treated... 

Helium is produced in the United States from some natural gas fields. This source was discovered in 1905 by H. R Cady and D. F. McFarland at the University of Kansas, when they were asked to analyze a nonflammable component of natural gas from a Kansas gas well. Uses of the noble gases are summarized in Table 24-2. 

As with petroleum, natural gas from different wells varies widely in composition and analyses (Speight, 1990 and references cited therein Speight, 1993 and references cited therein Speight, 1999), and the proportion of nonhydrocarbon constituents can vary over a very wide range. Thus a particular natural gas field could require production, processing, and handling protocols different from those used for gas from another field. 

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