Enap Educates

Origin of Hydrocarbons

Oil and natural gas were formed millions of years ago from the decomposition of plants and tiny organisms that, upon dying, settled at the bottom of the sea. These remains were buried under thick layers of gravel, sand, and mud, where they were exposed to pressure and temperature over time.

These hydrocarbons are found in regions distributed all around the globe, called sedimentary basins, formed by layers or strata stacked one on top of another, from the oldest to the most recent. In Chile, of the sedimentary basins with potential for hydrocarbon deposits, only the Magallanes basin has produced commercially viable quantities of these substances.

Natural gas does not only originate from the depths of the earth, but it can also be formed by small microorganisms known as methanogens (methane producers), which live in areas with low oxygen levels, such as the intestines of animals, including humans, as well as in freshwater and marine environments. The formation of methane by living organisms is called methanogenesis.

Uses of Hydrocarbons

Oil has been known since ancient times, with references to surface seepages and gas emanations dating back thousands of years. The first archaeological evidence of oil presence comes from Hit (Iraq), on the banks of the Euphrates River. About 6,000 years ago, asphalt was extracted from an oil seep. Asphalt was used to bind stones for construction, as well as for waterproofing ceramics and boats. On other occasions, oil appeared in streams of water, where it was collected and used for various purposes, such as ointments for treating wounds, skin diseases, or for massaging sore muscles.

In ancient Mesopotamia (modern-day Iraq, Syria, Kuwait, and parts of Turkey), around 4,000 B.C., bitumen, a raw tar, was used to waterproof boats, set jewels and mosaics, and as an adhesive for securing weapon handles. The Egyptians used it to embalm the dead, to grease leather, and to oil chariot wheels. It is also said that asphalt was used to bond the bricks of the Tower of Babel. About 2,000 years ago, the Chinese transported gas using bamboo pipes to heat and light their homes. The Maya and Aztec cultures painted sculptures with oil, and the first oil exported from Venezuela, in 1539, was used as a treatment for gout by Emperor Charles V.

Fossil Fuels

Fossil fuels are significant energy sources due to their high calorific value. They are primary sources of energy, as they can be obtained directly, without transformation. One of them is coal, a sedimentary rock rich in carbon and varying amounts of other elements such as hydrogen, sulfur, oxygen, and nitrogen.

Hydrocarbons are also fossil fuels. These are organic compounds primarily formed by carbon and hydrogen atoms. Oil is a hydrocarbon extracted in liquid form from a geological formation. Natural gas, on the other hand, is a hydrocarbon found naturally in gaseous form.

The Magallanes and Chilean Antarctic Region is rich in fossil fuels. It has abundant coal reserves and is the only region from which oil and natural gas are extracted. In recent years, studies have located unconventional hydrocarbon deposits, ensuring the continuation of oil and gas exploration in the region.

Oil Deposits

The largest oil deposits and main producers are in the Middle East, Latin America (Mexico and Venezuela), Africa, Eastern Europe, Russia, North America, and the Far East.

The Oil Producing Countries Organization (OPEC) includes Saudi Arabia, Algeria, Angola, the Republic of the Congo, the United Arab Emirates, Gabon, Equatorial Guinea, Iran, Iraq, Kuwait, Libya, Nigeria, and Venezuela. Other oil-producing countries are called "independent," with major players including the United Kingdom, Norway, Mexico, Russia, and the United States. The U.S. is the largest consumer of oil but is also one of the largest producers.

Methods of Oil Exploration

Oil reserves are found beneath the earth's surface, hundreds, or thousands of meters deep. To detect them with a certain degree of certainty, various studies are conducted, such as gravimetry, magnetometry, seismic studies, and, when there is a strong probability of economically viable accumulation, exploration drilling is performed.

Exploration Drilling: Rotary Drilling

Rotary drilling is the most widely used method today. This method involves creating a well by adding drilling pipes (steel tubes) as drilling progresses. At the bottom of the pipes, a drill bit is attached, and the entire system rotates, powered by diesel or electric motors. The drill bit consists of cutting elements with varying capacities to cut or grind, made from hardened steel or diamond inserts.

The material cut or crushed by the drill bit is removed by circulating drilling mud (a mixture of water, solids, and chemical additives). The mud also helps prevent the sudden release of hydrocarbons, mitigating the associated risks.