Formation of Oil and Natural Gas Reserves

Study Notes

Oil and natural gas reserves are commercially recoverable fossil fuels that are formed from the remains of dead organisms over millions of years through geological processes.
These reserves are trapped in deep subsurface rocks and can extend over large areas, requiring an integrated team of geologists and engineers to explore and extract them.

Geologists specialize in different branches of geology, such as stratigraphy, sedimentology, structural geology, seismology, and petroleum geology, to explore source rocks and reservoir rocks.
Hydrocarbons are extracted after finding them, designing and drilling wells, and refining and processing the extracted resources.
Reserve estimates are calculated using technologically advanced instruments and computer software, taking into account accessibility and producibility.

Proven reserves have a 90% probability of extraction, subdivided into proven developed and proven undeveloped.
Unproven reserves have significant uncertainties due to political and administrative issues, subdivided into probable and possible.

Fossil fuel resources are extracted through primary (traditional) and secondary methods.
Traditional methods involve vertical drilling and pumping, with oil flowing up through the wellbore due to pressure in the reservoir.
Secondary methods, such as water flooding, CO2 injection, steam flooding, polymer flooding, and hydraulic fracturing, are used to increase oil viscosity or movability.

Native Americans discovered oil in America by gathering from oil seepages and using them for medicine production.
Edwin Drake drilled the first intentional oil well on August 27, 1859, in Titusville, Pennsylvania, starting the oil industry in the United States.