Oil and Natural Gas Drilling similarities

Drilling for both the oil and natural gas has been taken up by many oil drilling companies in this world and this has been primarily with an aim to satisfy the energy requirements of the world. Indeed many nations across the world have put on their concerted efforts with an idea to harness these two forms of energy the oil and natural gas which already have proved themselves to be the key players of the world economy. There are numerous oil wells and gas wells across the world and several best producing oil wells for sale are listed here.

The various oil exploring and drilling companies across the world have made use of the modern technology to develop new and faster methods to drill out the oil and natural gas from the reserves beneath the earth. It is generally found that whenever a drilling is underway to bring out the crude oil contained within the oil well or the oil block, natural gas in addition with many other gases emanate out of the well.

Over the centuries the natural gas that has been given out during the drilling procedure of the crude oil is termed as its byproduct. In the late 1800's when the use of this natural gas that came out along with the crude oil was not known, it was often regarded as a nuisance and it was considered as a hazard for the oil explorers. Hence it was disposed off quickly by means of burning it.

It was only in the later years that it was discovered that this gas could very well be put to use for domestic and industrial purposes. This led to the ultimate storage of the natural gas in the form of cylinders and wherever possible it was sent through pipelines directly to the homes and many other industries for various types of applications. Natural gas consists mainly of methane gas. It is this methane gas which is a hydrocarbon that gives the burning ability to the natural gas.

There is another name that is related to the natural gas and it is often referred to as the "casinghead gas". Another name that it is attributed to the natural gas is "associated gas". In the case of the drilling of oil wells the former methods that were used for digging the oil wells centuries before, was to hand dig the well which ultimately was stopped when the oil makes its appearance. This system of hand digging was actually being practiced in the oil fields of Azerbaijan, where it is claimed that the oil wells were dug for nearly hundreds of meters down the earth's crust to finally reveal the crude oil. But with the passage of time this practice has given way to the modern technological methods where drilling machines are being used, which dig wells that are several meters deep. Hence to drill out the oil and natural gas more successfully from the surface of the earth, new techniques like the horizontal drilling and a still newer method like Nitrogen drilling methods are being put to use by the oil drilling companies worldwide.   (ArticlesBase SC #3929317)

Composition of Petroleum

An oil well produces predominantly crude oil, with some natural gas dissolved in it. So in common usage Petroleum includes both crude oil and natural gas. Whether crude oil or natural gas are predominantly a mixture of hydrocarbons. The lighter hydrocarbons methane, ethane, propane and butane, under surface pressure and temperature conditions, occur as gases, while the heavier ones from pentane and up are in the form of liquids or solids. Some of the gas come out of solution and be recovered as associated gas or solution gas, as the pressure is lower at the surface than underground. Some times gas recovered from gas well may contain heavier hydrocarbons such as pentane, hexane, and heptane in the gaseous state because of the higher underground temperature and pressure than that of the surface.

Under surface conditions these will condense out of the gas and form natural gas condensate, often shortened to condensate. Condensate resembles gasoline in appearance and is similar in composition to some volatile light crude oils.

The proportion of hydrocarbons in the petroleum mixture is highly variable between different oil fields and ranges from as much as 97% by weight in the lighter oils to as little as 50% in the heavier oils and bitumens.

The hydrocarbons in crude oil are mostly alkanes, cycloalkanes and various aromatic hydrocarbons while the other organic compounds contain nitrogen, oxygen and sulfur, and trace amounts of metals such as iron, nickel, copper and vanadium. The exact molecular composition varies widely from formation to formation but the proportion of chemical elements vary over fairly narrow limits as follows:

Composition by weight
Element	Percent range
Carbon	83 to 87%
Hydrogen	10 to 14%
Nitrogen	0.1 to 2%
Oxygen	0.1 to 1.5%
Sulfur	0.5 to 6%
Metals	less than 1000 ppm

Four different types of hydrocarbon molecules appear in crude oil. The relative percentage of each varies from oil to oil, determining the properties of each oil.

Composition by weight
Hydrocarbon	Average	Range
Paraffins	30%	15 to 60%
Naphthenes	49%	30 to 60%
Aromatics	15%	3 to 30%
Asphaltics	6%	remainder

Directional Drilling

An oil well is a general term for any boring through the Earth's surface designed to find and produce petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil, and a well designed to produce mainly or only gas may be termed a gas well.

The earliest oil wells were drilled percussively by hammering a cable tool into the earth. Soon after, cable tools were replaced with rotary drilling, which could drill boreholes to much greater depths and in less time. The record-depth Kola Borehole used non-rotary mud motor drilling to achieve a depth of over 12 000 meters (38,000 ft). Until the 1970s, most oil wells were vertical (although different lithology and mechanical imperfections cause most wells to deviate at least slightly from true vertical). However, modern directional drilling technologies allow for strongly deviated wells which can, given sufficient depth and with the proper tools, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal; a horizontal wellbore placed in a production zone has more surface area in the production zone than a vertical well, resulting in a higher production rate. The use of deviated and horizontal drilling has also made it possible to reach reservoirs several kilometers or miles away from the drilling location (extended reach drilling), allowing for the production of hydrocarbons located below locations that are either difficult to place a drilling rig on, environmentally sensitive, or populated.