Oilfield

Oilfield

A reservoir tank or reservoir oil is a natural accumulation of hydrocarbons in the subsurface, contained in porous or fractured rocks (reservoir rock). Natural hydrocarbons such as crude oil and natural gas, are retained by overlying rock formations with low permeability.

Training

Crude oil found in oil deposits in the lithosphere is formed from the remains of organisms ( fossils) past, deposited in large amounts in funds anoxic seas or lake areas of geological and covered by thick layers of sediment past. Millions of years of chemical transformations (Natural cracking ) due to heat and pressure during diagenesis , moved the remains of organisms (animals and plants ) in oil and natural gas. Murmi Roy , a director of Schlumberger , described the process as follows : " Plankton and algae , proteins and life floating on the sea , when they die they fall to the bottom , and these organisms are the source of our oil and gas. When buried with accumulated sediment and arrive at a suitable temperature , somewhat above 50 to 70 ° C begin to cook. This transformation , this change, becomes liquid hydrocarbons that move or migrate , reaching form our oil and gas deposits ".

Primary deposits

The oil reservoir can be primary, when in the same rock that is formed either be a secondary site, when it was formed in a remote location and has been flowing to the point where now lies motion with which changed some of its properties.

Of course in the primary deposit is to find the following provision: an upper layer of impermeable clay below it a layer of impregnated sands natural gas (gaseous hydrocarbons) below impregnated sands oil (liquid hydrocarbons) and finally , a lower layer of impregnated sand saltwater. With this placement, the upper impermeable layer traps the oil in the same place where it was formed and not allowed to escape, only be separated following a gradient density of salt water containing (more dense) and the so-called natural gas (gas group less dense than oil).

Secondary deposits

In a secondary site, the continuous arrival of hydrocarbons to trap oil causes it to accumulate in a significant enough amount and concentration as to make very profitable oil exploitation.

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