How does oil and gas come out of the ground?

Can someone please detail some applications used to get oil out of the ground and explain what happens to it when it does?How does oil and gas come out of the ground?
Oil and gas come out of the Ground in various forms





The most typical product is crude oil (Usually namesd after the field it is produced from, such as Brent Crude / Ninian Crude etc) Other products include Gas which can come in dry or saturated (wet) forms (ike gas condensate). In either instance, Oil and Gas require a degree of seperation after they are circulated into a platforms process system.





To get the oil and gas out of the ground, Geologists perform surveys on areas ready for oil exploration. Using various seismic techniques including exploratory drilling, they determine the likelyhood of a field being ';economically viable'; in terms of installing a platform or FPSO (Floating Production / Storage Offloadiing) vessel.





In the instance where an oil company decides to capitalise on a find, either onshore or offshore, the commisioning phase of oil production is started.





An oilfeild is in basic terms a big pourous rock with the properties not unlike those of a sponge, that contains hydrocarbons. In order to free up these hydrocarbons and circulate them to the surface, they must firs drill wells to tap into the supply. During a feilds initial life, it is sometimes found that the ';reservoir'; is positively charged (pressurised) and flows freely without any assitance to do so. In later life, these wells require ';stimulation'; and ';well intervention'; drilling based technologies that essentially increase asset uptime, preventing delays in processing crude / gas and pumping it ashore.





A well has 3 significant parts, Casing, Tubing and completion. In relative terms, the casing is the outside shell of the well, that prevents the pressures of the well breaching containment and spilling into the ocean or landscape. Tubing is used to produce oil back to the surface or alternatively treat the well with specialist chemicals.The area between the casing and tubing is called the annulus, and must also be pressurised with a drilling fliud in order to equalise the pressures associated with oil and gas production.





Coiled tubing is a well intervention technique develped specifically to perform well maintenance. It has numerous applications but in the north sea it is commonly used as a ';gas lift'; technique - so called because it pumps an inhert gas (N2) downhole to charge a dead reservoir and pring on production. - usually, a platform will have its own produced water system that is designed to do the same thing o a larger - more permenant scale.





There are lots more applications but I hope your happy with what I've written :DHow does oil and gas come out of the ground?
It is mined. And then it is used as petrol, diesel etc.
when they drill to a position that has gas, because of the high pressure that gas has in the ground it comes up by itself,no means required.


for oil its a little more tricky.I think that they pump steam to the oil in order to create pressure difference and the oil comes up to surface
THey are both mined....pretty much put a drill into the ground and suck up the stuff.





Now oil has no chemical formula. Its carbon molecules with varying length of the carbon chain. You can have C2....or C100...etc That is...the number of carbons in 1 molecule of the oil.





Usually the oil is taken to some sort of ';cracker';. Pretty much pour the oil into a giant distillation collumn, crank up the temp to a few thousand degrees (no oxygen so it doesn't blow up).


IN here the molecules get broken up into various sizes (methane, ethane,propane.........etc)





Now the temperature in this column varies. Top of the column is cooler than the bottom and it gradually gets hotter towards the bottom.





If a heavier molecule is at the top of the column, it'll turn into liquid and drip down.....if a lighter moleucle is at the bottom...it'll vaporize and float up.





There are exits all along the column. You get your methane, ethane, propane butanes....... towards the bottom you get your diesel, jet fuel. The very bottom is usually used for asphalt.
When an oil/gas reservoir has been discovered, the objective is to get it out of the ground.


This is accomplished by drilling a well and running piping into the hole.


The final act of drilling is to fix an assembly of valves onto the piping at the top of the well.


This assembly is called a Christmas Tree (Xmas-tree) and, as one valve is not enough to control oil flow safely, at least two valves are needed.


The first one is called the Master Valve which is normally kept open and is used only as an isolation when the second valve fails to operate or when under maintenance.


The fluids from a well, will normally come to the surface under the pressure built up underground when they were forming millions of years ago.


When a well has been producing for many years and its natural pressure has diminished to a point where production is too low. Other procedures can be carried out to recover more oil if it's available.


These are: Gas lift gas injection operations; Installation of a down-hole pump; Injection of water from an adjoining water table to build up the water drive under the oil in the reservoir





The Xmas-tree is connected to piping (flowlines) to carry the oil and gas (and produced water) to the separation plants where the gas is separated and fed to compression units, sweetening (H2S removal) and dehydration plants and sent on for further processing.





The oil is separated from water and is sent to refineries for further processing.


The water is drained away to 'skimming' tanks to remove traces of oil and disposed of.
Mostly upward...