The Science of Gas
    Most petroleum and natural gas are produced by the degradation of kerogen within the Earth by naturally occurring heat. Kerogen is an insoluble product derived from sediment being deposited at the bottom of seas and lakes, transforming organic matter with bacterial activity. The sediments containing the organic matter that produces gas are clays or fine limestones, which are mainly compact and relatively impermeable. The gas is expelled and migrates to reservoir levels, which are made up primarily of sands and sandstones, and are porous and permeable.

    Natural gas is a mixture of flammable gases, mainly the hydrocarbons methane and ethane, that occurs beneath the surface of the Earth. Helium is also found in relatively high concentrations in natural gas. Natural gas usually occurs in association with petroleum because geological conditions favorable for it generally are favorable for natural gas occurrence as well. Although many natural gases can be used directly from the well without treatment, some must be processed to remove such undesirable constituents as carbon dioxide, hydrogen sulfide, and other sulfur components.

    Depending on the region the gas is from, constituent percentages are somewhat different. For example, natural gas in the western United States may be 77% Methane, 16% Ethane, and 7% carbon dioxide, while in the eastern half of the country, it may be from 83 to 90% Methane, 5 to 15% Ethane, and even have some small percentage of Nitrogen included. Specific gravity of natural gas is usually around .60, but can be as high as .070. Various regions of the world can vary just as greatly.

    Methane is a colorless, odorless gas that occurs abundantly in nature as the chief constituent of natural gas and as a component of firedamp in coal mines. The chemical formula is CH4. In general, methane is very stable, but mixtures containing 5 to 14 percent in air are explosive.

    Properties of Methane

    Symbol CH4
    Atomic weight 16.04
    Boiling point -259ƒ F
    Density .042 Lb per Cu Ft
    Specific gravity 0.55

    Ethane is a colorless, odorless, gaseous compound of hydrogen and carbon with a chemical formula of C2H6. The second most important constituent of natural gas, it also occurs dissolved in petroleum oils, as a by-product of oil refinery operations, and of the carbonization of coal.

    Properties of Ethane

    Symbol C2H6
    Atomic weight 30.07
    Boiling point ñ173.53ƒ F
    Density .080 Lb per Cu Ft
    Specific gravity 1.05

    Propane is a colorless, easily liquefied, gaseous compound of carbon and hydrogen. It is separated in large quantities from natural gas, light crude oil, and oil refinery gases. Its chemical formula is C3H8.

    Properties of Propane

    Symbol C3H8
    Atomic weight 44.0
    Boiling point ñ42.1ƒ F
    Density .116 Lb per Cu Ft
    Specific gravity 1.52

    Butane is a colorless, odorless, gaseous compound of carbon and hydrogen, and its chemical formula is C4H10. Butane occurs in natural gas and in crude petroleum, and is formed in large quantities in the "cracking" of oil to produce gasoline.

    Properties of Butane

    Symbol C4H10
    Atomic weight 58.12
    Boiling point 31.1ƒ F
    Density .149 Lb per Cu Ft
    Specific gravity 1.95
    Other Gases

    Argon, most abundant and industrially used of the noble gases on the periodic table, argon is used in gas-filled electric light bulbs, and fluorescent tubes and in Geiger counters. An odorless and colorless gas, argon is also used as an inert gas shield in welding. It is usually found in rocks and crystals.

    Properties of Argon

    Symbol Ar
    Atomic number 18
    Atomic weight 39.948
    Group in periodic table O
    Boiling point-302.3ƒF (185.7ƒC)
    Density 1.784 grams/liter
    Specific gravity

    Nitrogen, is often used as an "inert" gas due to its non-reactive nature with many materials. However, nitrogen can form certain compounds under the influence of chemicals, catalysts, or high temperature. Gaseous nitrogen is used in the chemical and petroleum industries for tank blanketing and vessel inerting applications. It is also used extensively by the electronics and metals industries for its inert properties.

    Properties of Nitrogen

    Symbol N2
    Atomic weight 28.01
    Boiling point-320.4ƒF (-195.8ƒC)
    Density 0.0725 Lb per Cu Ft
    Specific gravity 0.96

    Oxygen, is one of the most common types of gases, known principally for life-sustaining and its strong oxidizing properties. It is used in medicine for therapeutic purposes, and in the metals industry for steelmaking and metal-cutting applications. It is also used in various industrial applications to reduce particulate and Nox emissions.

    Properties of: Oxygen
    Symbol O
    Atomic number 8
    Atomic weight 15.9994
    Group in periodic table O
    Boiling point-182.862ƒ C
    Freezing point-308.56ƒF (-189.2ƒC)
    Specific gravity 1.10

    Acetylene
    Symbol C2H2
    Atomic weight 26.04
    Boiling point-103.0ƒ F
    Specific gravity .905

    Ammonia
    Symbol NH3
    Atomic weight 17.03
    Boiling point-28.8ƒ F
    Specific gravity .60

    Carbon Dioxide
    Symbol CO2
    Atomic weight 44.01
    Boiling point-109.2ƒ F
    Specific gravity 1.52

    Neon
    Symbol Ne
    Atomic weight 2.018
    Boiling point-410.9ƒ F
    Specific gravity .967

    Helium
    Symbol He
    Atomic weight 4.003
    Boiling point-410.9ƒ F
    Specific gravity 0.138

    Hydrogen Sulfide
    Symbol H2S
    Atomic weight 34.08
    Boiling point-410.9ƒ F
    Specific gravity 1.189

    Air
    Symbol None
    Atomic weight 26.96
    Boiling point-317.8ƒ F
    Specific gravity 1.0