OIL AND NATURAL GAS

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Okan YARDIMCI

What is Oil?

Together with natural gas, it makes up  petroleum, which is Latin for "rock oil". Petroleum is basically a mix of naturally occurring organic compounds from within the earth that contain primarily hydrogen, carbon and oxygen. When petroleum comes straight out of the ground as a liquid it is called crude oil if dark and viscous, and condensate if clear and volatile. When solid it is asphalt, and when semi-solid it is tar. There is also natural gas, which can be associated with oil or found alone.

      Crude oil comes in many forms (Crude oil is petroleum that has been pumped out of the ground and has not been refined yet. It smells like sulfer and is very stinky. Crude Oil can be refined into gas, gasoline, kerosene, gas oil, fuel oil, and long residue.) Usually it is black, but green, red or brown oils are not uncommon. Thin and volatile oils are called "light", whereas thick and viscous ones are "heavy". Light oils have an API gravity of 30 to 40 degrees, which means that the density is much less than 1.0 g/cc. These oils float easily on water. By contrast, some heavy oils have an API gravity of less than 12 degrees and are so dense that they sink, rather than float, in water.

           Most oils are mixtures of many different compounds, most of which are hydrocarbons. There are four main hydrocarbon groups in petroleum. The saturates are hydrocarbons consisting of straight chains of carbon atoms. Aromatics are hydrocarbons consisting of rings of carbon. Asphlatenes are complex polycylic hydrocarbons that contain many complicated carbon rings, and NSO compounds are mostly nitrogen, sulfur, and oxygen.In most oils, the saturate fraction is the largest and is made up of two subgroups called paraffins and isoprenoids. Paraffins are simple straight-chain hydrocarbons, whereas isoprenoids are hydrocarbon chains with branches. Waxes are long-chain paraffins that are solid at surface temperatures and may contain as many as 50 carbon atoms. Waxy oils tend to thick and viscous, whereas aromatic oils tend to be light and volatile.

Where Does Oil Come From?

...from deposits of decayed matter formed hundreds of millions years ago.

• In the Seasthat covered most of the earth, millions of plants and animals lived and died.
• Dead Organisms Accumulatedin layers on the sea bottom and mixed with sand and mud.
• Ages of Layeringchanged the mud and sand to stone. Increased heat and pressure formed petroleum from the dead plants and animals.
• Reservoirs of Oilwere formed when petroleum collected in porous rock layers.

How the Oil Industry Developed?

Oil has been used for thousands of years, but relatively recent discoveries and innovations have led to today's oil industry.

Early History: Limited Use
Ancient Greeks poured oil on the sea to set fire to enemy fleets.

Early 1800'S: New Uses
During this time, the whale oil used to light homes grew scarcer and more expensive. Natural gas was used more and more for illumination. A new source for lighting was also discovered-kerosene. Oil also proved to be an excellent lubricant.

1859: First Drilled Well
People began to look for oil under the earth. In Pennsylvania, Colonel Edwin Drake drilled 69 feet deep and struck oil. From that time on, drilling became the method for obtaining oil. The Civil War brought increased need for lubricants and lamp oil, leading to an intense search for oil.

1901: First Gusher
Anthony Lucas, a Louisiana mining engineer, believed that oil could be found in salt dome formations, such as the one at Spindletop, near Beaumont, Texas. In 1902 he struck oil, proving his theory. This first gusher was also the first major success for rotary drilling. People began to drill oil in many parts of Texas.

1901-1920: Growing Demand
The invention of mass-produced, gas-powered automobiles and oil-fueled boilers led to a steady growing need for petroleum. World War I increased demand for oil products, including new ones like airplane fuel. This in turn increased the need for new supply sources, refining processes, and transportation systems.

1920-1940: New Refining Method & Uses
To meet growing demand, scientists developed new ways to refine petroleum so that more gasoline and related products could be derived from every barrel of crude oil. New processes were also discovered that led to the creation of hundreds of new products.

Today
The field of petrochemicals has expanded so much that oil has become a foundation of our way of life.

Common, everyday products made from oil include: plastics, detergents, paints, and varnishes, photographic films, drugs and medicines, synthetic rubber, synthetic fibers, fertilizer and thousands more. a basic part of over 6000 products. It's Our Major Source of Energy. Petroleum supplies about 45% of our total energy requirements.

What is Natural Gas?

Natural gas is one of the cleanest burning fuels found in the world today.Natural gas is made up of hydrocarbons, a mix of hydrogen and carbon. The main hydrocarbon is methane, (CH4) the simplest member of the alkane hydrocarbon family, with ethane, propane and butane in smaller amounts. Hydrocarbons are the energy rich parts of natural gas. Some natural gas also contains traces of other substances such as carbon dioxide, nitrogen, water and sulphur. These substances are non-combustible. If they are present in the gas in high concentrations then they must be substantially removed before the gas can be used as a fuel. Kapuni gas with a carbon dioxide content of around 42% is a good example of this. The carbon dioxide is reduced to around 2-3% at the Kapuni gas treatment plant before it is transported by pipeline to the market place. Natural gas is colourless and odorless, although sometimes it may have a slight oily or swampy smell in its natural state. The distinctive smell associated with gas comes from the strong odorant injected into the gas as a safety measure so that leaks in pipelines and appliances can be quickly located. Because natural gas is colourless small amounts cannot be seen. A large amount may be seen as a shimmer or haze, like a heat haze on a hot day. A lot of gas under pressure can be seen quite clearly. As natural gas is lighter than air, a little more than half the weight of air, it rises into the atmosphere and does not form dangerous pockets of gas if there is a gas leak, unless this occurs in a confused, unventilated space.Natural gas is not toxic or poisonous, unlike gas produced from coal and car exhaust fumes, which contains carbon monoxide. However, care still needs to be taken around natural gas. As natural gas displaces air, large quantities in a confined space could suffocate.

Natural Gas is a valuable source of energy. It is used for:

• Heating
• Cooking
• Drying
• Barbecues
• Fireplaces
• Cars

Natural gas began to be used as an illuminant and a fuel on a large scale in the late 19th cent.  When pipelines were built to provide it to large industrial cities. In industry, natural gas is used to manufacture pulp and paper, metals, chemicals, stone, clay, glass, and to process certain foods. Gas is also used to treat waste materials, for incineration, drying, dehumidification, heating and cooling, and cogeneration. The Clean Air Act Amendments have made natural gas an even more popular energy choice for industry. Natural gas is also used for heating, cooling, production of electricity, and has been used on a small scale in recent years as an alternative fuel for automobiles and other vehicles.

What About Our Environment?

Natural Gas and the Environment : Natural gas is today’s affordable environmental solution. Using more natural gas in place of other fuels helps answer several environmental problems at the same time, including smog, acid rain and greenhouse gas emissions. "As a fossil fuel, natural gas has far fewer harmful effects on the environment than coal or petroleum. It has virtually no sulfur emissions, lower emissions of nitrogen oxides, and extremely low particulate emissions. Natural gas has approximately 30 percent lower carbon dioxide emissions than oil and 45 percent lower carbon dioxide emissions than coal, on an energy-equivalent basis, and does not generate solid waste." Coal, oil, and products made from them, such as gasoline, have much more complicated molecular structures than natural gas. This results in greater emissions of carbon monoxide, carbon dioxide, sulfur dioxide and nitrogen oxides when they are burned. Coal and industrial fuel oil also produce particulates—small particles that do not burn and that can be carried into the atmosphere. There is increasing concern for the ill health effects of particulates.Natural gas often competes with electricity in many applications. But while electricity can be very efficient and clean, it is usually much less efficient and environmentally friendly than natural gas overall because electricity is not a primary energy; another energy source such as gas, coal, oil or nuclear must be used to create it.

Okan YARDIMCI,

Petroleum and Natural Gas Engineer