Oil and natural gas are the two primary types of fossil fuels that the world relies on for energy and also for various other products. Crude oil and gas are mined beneath the earth’s surface where they formed a long time ago. The products origin can be traced back to the remains of animals and plants that existed millions of years ago as marine life. The living materials die and sink to the sea floor where they pile on top of each other. The successful conversion of the remains into oil or gas is only possible if the materials are covered by mud, minerals or sand. The rapid covering and burial prevent decay from occurring immediately (Harold, 106). When organic materials remain exposed on the sea floor, they decompose and cannot be converted into fossil fuel. The buried materials have low oxygen levels which facilitate the conversion.
The conversion of organic matter into oil and gas initially begins with bacterial processes. The organic materials are transformed into carbon-rich compounds within the sedimentary layers. The organic materials are contained within fine-grained sedimentary rocks and mineral grains (Plummer et al. 156). When the carbon-rich compound mixes with surrounding sediments, they form the source rock. The source rock is buried deeper into the earth’s crust when new sediment layers are formed and deposited on top of one another. The source rock can be buried several miles underneath the surface of the earth (Plummer et al. 154). The formation and accumulation of other rock layers are critical because it applies pressure on the source rock. They also perform the function of preventing oxygenation of the carbon-rich compounds.
The fine-grained shale is exposed to heat present under the surface of the earth because of being buried to a depth of several thousand feet. The combination of the heat and the pressure acts on the source rock and chemically convert the compounds into natural gas or crude oil (Harold, 104). The primary resulting compound after natural gas formation is methane. The resulting compounds are expelled into porous rocks mostly adjacent to the source rocks. The reservoir rocks are saturated with water which is less dense than oil and gas causing them to rise upward. The compounds move upwards through porous reservoir rocks and only stop when they encounter impermeable rocks. Accumulation of the oil and the gas at such a point results in the formation of crude oil or a gas field.
The process of oil and natural gas formation concerns the world supply because it takes a considerably long time for the products to be ready for mining. Crude oil and gas are major sources of energy in the world today (Robert, 7). The two components also provide a wide range of products and their absence in the world would make a huge difference. The conversion of organic matter resulting from animal and plant remains to crude oil, and natural gas takes millions of years. The process takes millions of years for the products to be formed to completion. The concern is that because the process takes very long, the available sources might become depleted before new ones are formed. The availability of gas and oil is dependent on the availability of the same in underground fields.
The process concerns the supply of oil and gas because there are several requirements in nature that must happen simultaneously for the conversion to occur. For example, when the burial is not rapid enough, the organic materials decay and do not form the carbon-rich compounds. The world is also concerned because the rate at which the oil fields are being mined is increasing compared to the rate at which new deposits are being formed. The reliance on fossil fuels has been increasing over the years. Oil mining is increasing with more mines being drilled consistently. The supply of the oil and the gas will reach a point where it is not able to meet the demand in the world. The major reason is that the process of making new oil and gas takes millions of years.
Another reason the process of oil and gas formation is a concern to the supply is that the oil fields are buried underground. The source rock that facilitates the formation of oil and gas is deeply buried by layers of sediments and rock layers. The oil and gas fields are in between layers that could be among thousands of feet under the surface of the earth (Robert, 7). The depth of the fields considerably affects the cost of mining the oil and gas. The deeper the fields, the higher the cost of drilling the wells and bringing the products to the surface. The limitation is that fields that are less than substantial cannot be mined because it is not economical. If the fields were nearer to the surface, then even the small sized fields could be mined. The result is that the supply will be affected because the small fields could not be exploited.
Works cited
Plummer Charles, Diane Carlson and Lisa Hammersley. Physical Geology 14th ed. New York: McGraw-Hill Education. 2012. Print.
Harold Schobert.The Chemistry of Fossil Fuels. New York: Cambridge University Press.2013. Print.
Robert Curley. Fossil Fuels. New York: Britannica Educational Publishing. 2012. Print.
