As oil is extracted

Currently the vast demand for energy demands that need to seek oilfields in areas that were once unthinkable for its inaccessibility and what they are designed numerous ways in which the oil is extracted. oil is extracted at great depths in the sea under a lot of depth and even ground may be easier removal will sometimes have to settle in inhospitable places like the desert of Algeria.
In the beginning, the percussion method was used when the oil wells were shallow and under rocks very hard, this technique since the mid-twentieth century gave way to the rotation method, since most of the oil has been determined which it lies at a depth of between 900 and 5,000 meters, although there are wells that reach 7,000 or 8,000 meters.
Rotation method
It consists of a pipe system coupled one after the other that, driven by a motor, they are turning and drilling down. In the end a drill or drill with teeth that break the rock that separate blades and diamond drilling that, depending on the type of terrain is. Furthermore, there is a movable pulley system of the set of tubes prevents suspending the whole weight of -the tubes wells have depths of thousands of meters-fall on the bit.
Jacketed
To prevent the borehole from collapsing during drilling and at the same time, the structure of subsurface strata remains unchanged, as will drilling the well, it will be coated by a wall, or a steel shirts- thickness of between 6 and 12 millimeters.
Use the site
The historical calculations are such that oil usually a bag usually only utilized between 25% and 50% of its total capacity. Oil is often accompanied by gas bags. Both the depth to which are they are subjected to high-pressure gas, by that fact, it remains in liquid-state. Upon reaching the drill bit, the breakage of the impermeable rock causes the pressure to drop, so that, firstly, the gas no longer dissolved and the oil expands and stops having the impermeable rock barrier and usually being pushed by the salt water that usually permeates the porous rock that lies beneath the oil bourse. These two circumstances make the oil rises to the surface.
Pumping oil
However, there comes a time when the internal pressure of the bag
decreases to a point where the oil ceases to ascend one-and, moreover, gas, shrinking, stops pressing on CRUDE, so we must force by pumps to rise.
The pumping is performed until such time that the system cost
extraction is greater than the yield obtained from oil, so that the well is abandoned.
Water injection.
To increase the profitability of a site often used a system of water injection wells with parallel. While
a well oil is extracted, another made near the front is
injects water into the bag, which causes no pressure drop and oil remains pushed to the surface, and in a more profitable way the bombs.
This system increases the possibility of exploitation of a well to about 33% capacity. Depending on the terrain, this efficiency reaches 60%.
Steam injection
In reservoirs with very viscous oil (textured wax) injecting steam, instead of water, which allows to achieve two effects is used:
1) On the one hand, is increased, as with water, bag pressure oil to continue to rise freely.
2.) Furthermore, steam reduces the oil viscosity, thus becomes easier removal as it flows faster.
Extraction at sea
Advances in drilling techniques has allowed to develop wells from platforms in the sea (offshore) in waters of a depth of several hundred meters.
In them, to facilitate removal of the perforated rock is constantly recirculates slurry through the drill pipe and a nozzle system in the drill itself.
With this, they have managed to drill wells 6,400 meters deep from sea level, allowing access to a major share of global oil reserves.