In the name of Allah

petroleum engineering

Accumulate placeThe oil is accumulated in the rocks that called reservoirs.The rock must have some properties to become a reservoir such as porosity, permeability,... .We have three kind of rocks: source rocks, reservoir rocks, cap rocks.

MigrationAs I said the oil accumulated in rock like water in a sponge. These stones are under pressure upper stones weight and they have to been compressed and fill their self porosities but the fluids that exist there prevent them then the fluids move up. This is known as migration.When the fluids arrive to cap rock they can’t pass from the rock because of the rock property and their pressure began to increase.

Reservoir pressure

After migration the reservoir pressure be stable and decrease during the production.This stable pressure sometimes become more than 7000psi.At Iran's reservoirs pressure is about 5000psi(normal pressure is 14.696 psi).At the beginning of producing a well we don’t use anything to pump the oil to the surface.

Oil well

First well has been drilled was in 24th January 1859 via colonel Edvin Lorentin derrick in Pennsylvania America.Some months after drilling derrick well in 27th august 1859 a new well with 230m depth was drilled.These two wells and the oil exploration were the most important discovering in the second half of 19th century.

Well depth

The deepest well of the word is in Russian island “sakharin” with 7.7mile(12.39 km) depth that 7.1mile(11.42 km) of it is in offshore. they use 4 power plant with 7500psi power.This team is working on a project that will drill the well until 9.3mile(15km) at this island now.

Non-vertical & Forked well

In non-vertical wells(directional drilling)we drive out the well from its vertical form and sometimes become horizontal.One of the new technology that uses in the petroleum industry is forked well. In forked wells at first we drill a well then with directional drilling technology drill a new well in another direction in well. this work happens frequently in a well and we have many wells in first well and new wells and secondary wells.The most forked well in the word has 30 branch.

Well blowing outThis means when the wells become incontrollable for us that is called “wild well”. At this well the reservoir fluid is blew out.Two of the biggest blowing out (with comparing the volume of the oil lost):2-The second biggest blowing out happened in 20th April of 2010 in Mexican golf in Macando well that was drilling with Horizon rig via British petroleum company. In this incident about 53000 bbl/day of oil for three months and a total of five million bbl. of crude oil was flowed into the Gulf of Mexico.

Well blowing out

1-The biggest blowing out was happened in 26th august 1956 in well N.O. 5 in Alborz oil field in Qom. At this incident it lost 120 thousand bbl/day for a hundred days.(in some citations 150 days) the height of its fount was about 52m.

largest oil reservesThe biggest oil field is the Ghawar field in Saudi Arabia with 75-83 billion bbl reserve.the country with biggest oil reserve is Venezuela with 297.6 billion bbl then Saudi Arabia (267.1 billion), Canada (173.1 billion), Iran (154.4 billion) and Iraq (141.35 billion).