Natural gas deposits

Renewable carbon resources is a misnomer the earth s carbon is in a perpetual state of flux. Carbon is not consumed such that it is no longer available in any form. Reversible and irreversible chemical reactions occur in such a manner that the carbon cycle makes all forms of carbon, including fossil resources, renewable. It is simply a matter of time that makes one carbon from more renewable than another. If it is presumed that replacement does in fact occur, natural processes eventually will replenish depleted petroleum or natural gas deposits in several million years. Eixed carbon-containing materials that renew themselves often enough to make them continuously available in large quantities are needed to maintain and supplement energy suppHes biomass is a principal source of such carbon. 

Tetramantane, pentamantanes, and hexamantanes are found in some deep natural gas deposits [57, 58] but are not readily synthesized in the laboratory. 

He is found in natural gas deposits principally because alpha particles are produced during natural radioactive decay processes. These alpha particles are 4 He nuclei they obtain two electrons from the surrounding material to become helium atoms. This gaseous helium then accumulates with the natural gas trapped beneath the earth. Although other noble gases are produced by radioactive decay—notably 40 Ar—they are not produced in the large quantities that helium is. 

Just as oil, natural gas is also categorised as conventional and unconventional. Unlike crude oil, however, natural gas deposits are normally classified according to the economic or technical approach, i.e., all occurrences that are currently extract-able under economic conditions are considered conventional, whereas the rest are termed unconventional. Conventional natural gas includes non-associated gas from gas reservoirs in which there is little or no crude oil, as well as associated gas , which is produced from oil wells the latter can exist separately from oil in the formation (free gas, also known as cap gas, as it lies above the oil), or dissolved in the crude oil (dissolved gas). Unconventional gas is the same substance as conventional natural gas, and only the reservoir characteristics are different and make it usually more difficult to produce. Unconventional gas comprises natural gas from coal (also known as coal-bed methane), tight gas, gas in aquifers and gas hydrates (see Fig. 3.17). It is important to mention in this context so-called stranded gas , a term which is applied to occurrences whose extraction would be technically feasible, but which are located in remote areas that at the moment cannot (yet) be economically developed (see Section 3.4.3.1). 

Hydrogen sulfide enters natural waters from decay of organic matter (e.g., in swamps), bacterial reduction of sulfate ion, or underground sour natural gas deposits. It can be removed by aeration, anion exchange (Eq. 14.14), or oxidation by chlorine to elemental sulfur ... 

Fossil fuel deposits are not distributed evenly throughout the world. For instance, 65 percent of the world s recoverable petroleum deposits are in the Middle East, along with 34 percent of recoverable natural gas deposits. North America is relatively poor in petroleum and natural gas but has a bit more than one-fourth of the world s supply of coal. 

Coalbed Methane (CBM) A natural methane gas that is found in coal seams, while traditional natural gas deposits are trapped in porous rock formations. A small amount of CBM is already produced successfully in the Rocky Mountain region of the U.S. 

In Australia, also, there exists an impending shortage of domestic crude oil, but vast reserves of natural gas are available in the Australian N.W. Shelf natural gas deposits. It has been shown in some studies (3) that M15 synthesized from domestic natural gas is the most economic solution to the crude oil shortage in Australia. 

The first example, discovered by Humphrey Davy in 1811, was C12-7H20. Hydrates are commonly obtained when water is frozen in presence of a gas such as Ar, Kr, Xe,27 Cl2, C02, and so on. Methane hydratej28 occurs as a solid under permafrost or on the deep sea bed in various parts of the world in vast quantities. Utilization presents problems and is not likely to be necessary for some time when conventional natural gas deposits run out. 

When considering the higher hydrocarbons present in natural gas it is probably best to recall that a continuum exists in oil and gas reservoirs from almost pure methane to heavy petroleum oils and waxes. In general, hydrocarbon deposits do not span to the extremes higher hydrocarbon free natural gas is not commonly accounted although there are some very large natural gas deposits which comprise almost entirely methane . Thus many oil reserves have considerable quantities of associated gas and most gas reserves have associated with them light oil (condensate) deposits. 

Helium was identified by its characteristic emission spectrum as a component of the sun before it was found on earth. The major sources of helium on earth are natural gas deposits, where helium was formed from the a-particle decay of radioactive elements. The a particle is a helium nucleus that can... 

Assets used in exploration for and production of petroleum and natural gas deposits 5 6 7 10... 

Other gases are found on the surface of the earth and in the atmosphere. Methane (CH4), formerly known as marsh gas, is produced by bacterial processes, especially in swampy areas. It is a major constituent of natural-gas deposits formed over many millennia by decay of plant matter beneath the surface of the earth. Recovery of methane from municipal landfills for use as a fuel is now a commercially feasible process. Gases also form when liquids evaporate. The most familiar example is water vapor in the air from the evaporation of liquid water it provides the humidity of air. 

The helium we use for deep-sea diving and filling balloons is separated from natural gas as it is brought to the surface. This helium was formed in the depths of the earth by radioactive decay and remains trapped with the natural gas deposits. 

Although the methane in natural gas represents a tremendous source of energy for our civilization, an even more abundant source of methane lies in the depths of the ocean. The U.S. Geological Survey estimates that 320,000 trillion cubic feet of methane is trapped in the deep ocean near the United States. This amount is 200 times the amount of methane contained in the natural gas deposits in the United States. In the ocean, the... 

Petroleum and natural gas deposits probably formed from the remains of marine organisms that lived approximately 500 million years ago. Petroleum is a thick, dark liquid composed largely of hydrocarbons containing from 5 to more than 25 carbon atoms. Natural gas, which is usually associated with petroleum deposits, consists mostly of methane but also contains significant amounts of ethane, propane, and butane. 

Helium was identified by its characteristic emission spectrum as a component of the sun before it was found on earth. The major sources of helium on earth are natural gas deposits, where helium was formed from the a-particle decay of radioactive elements. The a particle is a helium nucleus that can easily pick up electrons from the environment to form a helium atom. Although helium forms no compounds, it is an important substance that is used as a coolant, as a pressurizing gas for rocket fuels, as a diluent in the gases used for deep-sea diving and spaceship atmospheres, and as the gas in lighter-than-air airships (blimps). 

Due to their low density, freshly formed oil and natural gas deposits migrate upwards through porous strata. Eventually, a large proportion of the hydrocarbons that were formed in the geological past reaches the surface, is lost to the atmosphere and degraded in an aerobic environment. Only those fractions that were trapped beneath an impervious layer of sedimentary rock remain to form oil and gas reserves, captured within the microscopic pore spaces of so-called reservoir rocks. 

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