Oil Deposits, Extraction and Refining

The areas of the Earth's surface where this phenomenon occurs more easily are those in the vicinity of the sea coast, ie large sedimentary basins of continental shelters. 

When formed, the oil is "squeezed" outside of the muddy material composed of sediments and organic material (mother rock) which is gradually compacting.

Main types of oil traps:

A) Anticline: It is a fold of rocks where the layers are convex upwards. In this geological structure, from bottom to top, water saturates all free pores, liquid hydrocarbons, gas accumulating at the top of the fold. 

B) Diapiros: salt intrusion allows the accumulation of oil in a permeable layer, blocking its rise. 

C) Fault: A fracture in a pack of rocks has made a permeable oil layer in contact with a waterproof layer, allowing accumulation of hydrocarbons. 

D) Angular bend: a permeable layer ends below a waterproof and thus allows accumulation of hydrocarbons.

 The oil that is formed tends to "migrate" to the nearest permeable rocks (usually sandstone or porous limestone), which become the warehouse rocks. 

The relatively low density of hydrocarbons leads them, in this phase of migration, to occupy the highest areas of storage rocks above the water in them. 

This creates an oil trap, with pressures reaching up to 900 atmospheres and temperatures of 150 ° C. If the oil trap permits the extraction of oil contained therein, it has an oil field arable. 

Oil drilling and GROWING

The identification of an oil field takes place through a series of geological and geophysical prospects. 

The drilling is mainly done with the rotary system (a screwed chisel at the end of a series of rods rotating on itself) that has almost completely supplanted the old percussion system (a heavy hammer fell periodically at the bottom of a well).To be carefully evaluated in the drilling phase is the push force of the shaft, in order to counteract, by means of mud, with an appropriate density, the sudden rise of hydrocarbons when reaching the oil layers. With the percussion system, at the moment when the JAPAN was reached , real explosions occurred, with considerable leakage of material.

To transform an oil drilling well into an extractive well, a casting is used to regulate the exploitation and replace the column inside the well with a siphon fitted with a special net that allows the passage of the liquid and of gas, but not of sand. Oil naturally rises due to the thrust forces in crude oil due to gas in solution, fluidized fluid from the gas, and so on. 

Subsequently, special systems are used to aid the rise of oil (input of water or gas under pressure, stimulation of crude oil to reduce viscosity, etc.). On top of a FIELD oil they can be opened hundreds of wells, to take advantage of the entire oil field.

Petroleum Refining and Petrochemicals

Petroleum Refining is the set of processes for the purpose of isolating from raw materials substances or mixtures of substances suitable for various uses, mainly as fuels ( LPG LIQUEFATTI GAS , HYDRAULIC GAS , fuel oil), solvents, lubricants, bitumen or as basic intermediates for the petrochemical industry on which many synthetic products such as plastics, synthetic fibers, elastomers, paints, pharmaceutical raw materials, detergents etc. are manufactured. Among the basic intermediates of the petrochemical industry are olefins (especially ethylene and propylene) and hydrocarbons AROMATIC .

The fractional distillation aims to separate the crude into some major gaseous, liquid and semisolid fractions (or cuts) by exploiting the different ranges at their distillation temperatures. It is carried out in plate distillation columns, where the various fractions are collected at different heights. 

The fractions are then subjected to further treatments, in order to obtain materials suitable for end uses. 

The CRACKING consists in the transformation of high molecular weight hydrocarbons in the other with a molecular weight less than subjecting them to high temperatures, often in the presence of suitable catalysts.

Reforming is also a catalytic process, with a twofold purpose: on the one hand to increase the yield in hydrocarbons AROMATIC , on the other hand to transform linear branched hydrocarbons. The latter, like the AROMATICs , are much more efficient than the fuel of modern internal combustion engines because they have more octane.