Geological formation in the context of "Petroleum"

The Mokattam Formation is a Middle Eocene-aged geological formation in northern Egypt. Consisting of nummulitic marine limestone outcropping across the Mokattam Hills, it has been extensively quarried from Ancient Egypt to the present day, and represents the source material for most of the famous archeological sites of Greater Cairo, most notably the Giza pyramid complex, the Great Sphinx, and much of Historic Cairo.

The age of the formation is thought to span from the late Lutetian to the Bartonian, depending on the member (Building Stone or Giushi). However, some authors treat the Giushi Member as its own geologic formation, which would restrict the Mokattam to just the Lutetian.

A fossil fuel is a flammable carbon compound- or hydrocarbon-containing material formed naturally in the Earth's crust from the buried remains of prehistoric organisms (animals, plants or microplanktons), a process that occurs within geological formations. Reservoirs of such compound mixtures, such as coal, petroleum and natural gas, can be extracted and burnt as fuel for human consumption to provide energy for direct use (such as for cooking, heating or lighting), to power heat engines (such as steam or internal combustion engines) that can propel vehicles, or to generate electricity via steam turbine generators. Some fossil fuels are further refined into derivatives such as kerosene, gasoline and diesel, or converted into petrochemicals such as polyolefins (plastics), aromatics and synthetic resins.

The origin of fossil fuels is the anaerobic decomposition of buried dead organisms. The conversion from these organic materials to high-carbon fossil fuels is typically the result of a geological process of millions of years. Due to the length of time it takes for them to form, fossil fuels are considered non-renewable resources.

In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fracture (or crack) in a rock formation or a vein of ore that is deposited or embedded between layers of rock. The current meaning (ore vein) dates from the 17th century, being an expansion of an earlier sense of a "channel, watercourse" in Late Middle English, which in turn is from the 11th-century meaning of lode as a "course, way".

The generally accepted hydrothermal model of lode deposition posits that metals dissolved in hydrothermal solutions (hot spring fluids) deposit the gold or other metallic minerals inside the fissures in the pre-existing rocks. Lode deposits are distinguished primarily from placer deposits, where the ore has been eroded out from its original depositional environment and redeposited by sedimentation. A third process for ore deposition is as an evaporite.

Oil and gas companies first used the processes involved in CCS in the mid-20th century. Early CCS technologies were mainly used to purify natural gas and increase oil production. Beginning in the 1980s and accelerating in the 2000s, CCS was discussed as a strategy to reduce greenhouse gas emissions. Around 70% of announced CCS projects have not materialized, with a failure rate above 98% in the electricity sector. As of 2024 CCS was in operation at 44 plants worldwide, collectively capturing about one-thousandth of global carbon dioxide emissions. 90% of CCS operations involve the oil and gas industry. Plants with CCS require more energy to operate, thus they typically burn additional fossil fuels and increase the pollution caused by extracting and transporting fuel.