Oil

Natural oil oily flammable liquid consisting of a complex mixture of hydrocarbons and other organic compounds. In color, the oil is red-brown, sometimes almost black in color, although sometimes there and poorly painted in yellow-green color and even colorless oil, has a peculiar smell, common in sedimentary rocks of the Earth. Today, oil is one of the most important minerals for mankind.

Overview

Oil is found together with gaseous hydrocarbons at depths of tens of meters to 5-6 km. However, at depths greater than 4.5-5 km dominated by gas and gas condensate reservoirs with a minor amount of light fractions. The maximum number of oil deposits located at a depth of 1-3 km. At shallow depths and natural outcrops on surface oil is converted into a thick Malta, semisolid asphalt and other education - such as tar sands and bitumen.

Chemical composition and origin of oil is close to natural gas fuel, ozokerite and asphalt. These resources are collectively called petrolytes. Petrolytes referred to even larger group of so-called caustobioliths - combustible biogenic minerals, which also includes solid fossil fuels.
Origin
Main article: Origin of oil

Oil - the result lithogenesis. It is a liquid (basically) a hydrophobic phase products fossilization (disposal) of organic matter (kerogen) in the water-sediment.

Oil formation - the step-wise, very long (typically 50-350 Ma) [6], a process that begins as early as living matter. Highlighted a number of stages:
Sedimentation - in which the remains of living organisms fall to the bottom of the basins;
Biochemical - compaction process, dehydration and biochemical processes with limited access to oxygen;
protokatagenez - lower layer of organic residues to a depth of 1.5-2 km, with a slow rise in temperature and pressure;
mezokatagenez or main phase of oil generation (GFN) - lower layer of organic residues to a depth of 3-4 km, with the rise in temperature to 150 ° C. In this case, the organic substances undergo catalytic thermal decomposition, resulting in formation of bituminous substances that make up the bulk of mikronefti. Further there is a distillation of the oil due to the pressure difference and stem emigration mikronefti in sand reservoirs, and on them in the trap;
apokatagenez kerogen or main phase of gas generation (GFG) - lower layer of organic residues to a depth of 4.5 km, with the rise in temperature to 180-250 ° C. In this organic matter becomes neftegeneriruyuschy metanogeneriruyuschy potential and realize potential.
IM Gubkin also singled stage destruction of oil mestozarozhdeny.

Strong evidence of the biogenic nature of the parent substance of oil were obtained from a detailed study of the evolution of the molecular composition of hydrocarbons and their biochemical precursors (progenitors) in the source organisms, organic matter and sediments and rocks in various oil from reservoirs. Important was the discovery of oil in the hemofossily - a very unique and often complex molecular designs clearly biogenic nature, that is inherited (in whole or in fragments) of organic matter. Study of the distribution of stable isotopes of carbon (12C, 13C) in the oil, organic matter of rocks and organisms (Vinogradov, EM Galimov) [7] also confirmed ineligibility inorganic hypotheses.

However, in the present, some scientists (mainly in Russia) advocate inorganic hypothesis of the origin of oil. In particular, it is argued that the newly formed in ancient times by organic oil is constantly added oil, which is formed by inorganic. If this is true, it means almost inexhaustible reserves of oil.