Composition of Crude oil and Natural gas in Drilling

Relatively simple crude-oil assays are used to classify crude oils as paraffinic, naphthenic, aromatic or mixed, based on the predominant proportion of similar hydrocarbon molecules. Mixed-base crudes have varying amounts of each type of hydrocarbon. One assay method (US Bureau of Mines) is based on distillation, and another method (UOP "K" factor) is based on gravity and boiling points. More comprehensive crude assays are conducted to determine the value of the crude (i.e., its yield and quality of useful products) and processing parameters. Crude oils are usually grouped according to yield structure, with high-octane gasoline being one of the more desirable products. Refinery crude oil feedstocks usually consist of mixtures of two or more different crude oils.

Crude oils are also defined in terms of API (specific) gravity. For example, heavier crude oils have low API gravitates (and high specific gravities). A low-API gravity crude oil may have either a high or low flash point, depending on its lightest ends (more volatile constituents). Because of the importance of temperature and pressure in the refining process, crude oils are further classified as to viscosity, pour points and boiling ranges. Other physical and chemical characteristics, such as color and carbon residue content, are also considered. Crude oils with high carbon, low hydrogen and low API gravity are usually rich in aromatics; while those with low carbon, high hydrogen and high API gravity are usually rich in paraffin.

Crude oils which contain appreciable quantities of hydrogen sulfide or other reactive sulphur compounds are called “sour.” Those with less sulphur are called “sweet.” Some exceptions to this rule are West Texas crude (which are always considered “sour” regardless of their H2S content) and Arabian high-sulfur crudes (which are not considered “sour” because their sulfur compounds are not highly reactive).

Hidrocarbon:

Paraffins: The paraffinic saturated chain type hydrocarbon (aliphatic) molecules in crude oil have the formula CnH2n+2, and can be either straight chains (normal) or branched chains (isomers) of carbon atoms. The lighter, straight chain paraffin molecules are found in gases and paraffin waxes. The branched chain paraffins are usually found in heavier fractions of crude oil and have higher octane numbers than normal paraffins.

Aromatics: Aromatics are unsaturated ring type hydrocarbon (cyclic) compounds. Naphthalenes are fused double ring aromatic compounds. The most complex aromatics, polynuclears (three or more fused aromatic rings), are found in heavier fractions of crude oil.

Naphthenes: Naphthenes are saturated ring type hydrocarbon groupings, with the formula CnH2n, arranged in the form of closed rings (cyclic), found in all fractions of crude oil except the very lightest. Single ring naphthenes (mono-cycloparaffins) with 5 and 6 carbon atoms predominate, with two ring naphthenes (dicycloparaffins) found in the heavier ends of naphtha.

Non-hydrocarbons

Sulphur or sulfur and sulphur compounds: Sulphur is present in natural gas and crude oil as hydrogen sulphide (H2S), as compounds (thiols, mercaptans, sulphides, polysulphides, etc.) or as elemental sulphur. Each gas and crude oil has different amounts and types of sulphur compounds, but as a rule the proportion, stability and complexity of the compounds are greater in heavier crude oil fractions.

Sulphur compounds called mercaptans, which exhibit distinct odours detectable at very low concentrations, are found in gas, petroleum crude oils and distillates. The most common are methyl and ethyl mercaptans. Mercaptans are often added to commercial gas (LNG and LPG) to provide an odour for leak detection.

The potential for exposure to toxic levels of H2S exists when working in drilling, production, transportation and processing crude oil and natural gas. The combustion of petroleum hydrocarbons containing sulphur produces undesirables such as sulphuric acid and sulphur dioxide.

Oxygen compounds: Oxygen compounds, such as phenols, ketones and carboxylic acids, are found in crude oils in varying amounts.

Nitrogen compounds: Nitrogen is found in lighter fractions of crude oil as basic compounds, and more often in heavier fractions of crude oil as non-basic compounds which may also include trace metals.

Trace metals: Trace amounts, or small quantities of metals, including copper, nickel, iron, arsenic and vanadium, are often found in crude oils in small quantities.

Inorganic salts: Crude oils often contain inorganic salts, such as sodium chloride, magnesium chloride and calcium chloride, suspended in the crude or dissolved in entrained water (brine).

Carbon dioxide: Carbon dioxide may result from the decomposition of bicarbonates present in, or added to crude, or from steam used in the distillation process.

Naphthenic acids: Some crude oils contain naphthenic (organic) acids, which may become corrosive at temperatures above 232 °C when the acid value of the crude is above a certain level.

Normally occurring radioactive materials: Normally occurring radioactive materials (NORMs) are often present in crude oil, in the drilling deposits and in the drilling mud, and can present a hazard from low levels of radioactivity.

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Nigeria, The First Crude Oil producer in The African Continent

Nigeria, or rather the region of the Niger Delta, is notorious for the continued tensions between local multinationals and guerrillas (and the consequent repercussions on the country's oil activity and crude oil prices) is one of the richest areas of hydrocarbons.

The quantity and quality of these resources have attracted the interests of the major Western companies that have been operating in the oil and, most recently, in the gas sector for decades.

The first crude oil producer in the African continent, member of OPEC, the country oscillates between the sixth and the eighth position as a world exporter and is the fifth supplier of the United States, while the recent results obtained under the NATURAL GAS liquid prelude to a protagonist future also on this market.

Nonetheless, over 60% of Nigeria's 150 million people live in an endemic poverty stash, with less than a dollar a day.

A situation of marginalization and exploitation to which the institutions could not answer - complicit also the corruption of a political class more attentive to their own personal interests than to the needs of the population - and who is degenerated into rebellion and violence perpetrated against the foreign oil installations and Western technicians, by local militias fighting in the name of the emancipation of their land and direct control over their resources.

In a descriptive and accessible way to everyone, the book by Agata Gugliotta, "Nigeria, whose resources? Oil and gas in the Niger Delta "reconstructs the economic and political life of Nigeria seen through black gold, the resource that still hinders the way of being a state enslaved to the needs of private capital; contextualizes the motives and developments of a revolt that, overwhelmingly overwhelmingly over time, has just recently swung to the backdrop of the media; analyzes what might prove to be a ransom for the country, or, conversely, an accelerator of the crisis: the exploitation of gas resources.

Burned in torch for decades, gas - considering the magnitude of RESERVES on site and its growing role in the international energy landscape - could offer the country a new stage of development and create opportunities to get out of the economic crisis and the climate of violence which attracts him.

But regardless of the time and the uncertainties related to the development of the gas sector, the economic and social degradation, the ' pollution of air, water and land every day that the Nigerian population is forced to suffer, they require urgent attention.

On the other hand, as the pages of this page show - written in a delicate but acute civil passion - the conflict that has bloomed Nigeria for a long time is likely to get stuck further, leading to a collapse of an economy already on the brink and making it increasingly difficult to see the presence and the " activities of Western multinationals.

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Crude Oil Transportation

There are two main ways of transporting crude oil: by tanker or through oil pipelines. 

Oil tanker: 

for about thirty years the oil was transported exclusively in barrels stacked in the ship's holds. In 1886, for the first time, oil was transported by an oil tanker with a carrying capacity of 3000 tonnes. Today, tankers can carry 550,000 tonnes. Regardless of its reach, an oil tanker is nothing more than a gigantic tank-shaped tank capable of floating. To limit these environmental disasters, new tankers are equipped with a double hull. So, in the event of a crash, the outer hull absorbs it, and even if it breaks, the oil remains in the ship with the second hull.

Pipeline: 

Oil, however, is mainly transported through large pipelines made of welded steel pipes, which are largely underground, where petroleum is driven by pumping stations. The pipelines are supported by steel and concrete supports. Before constructing an oil pipeline, thorough ground studies must be carried out on the ground where the latter will have to pass to find the easiest path to follow pipelines. A pipeline must be continually serviced to prevent faults or to repair any leaks. Oil pipelines can transport oil to a port, where they will be taken to a tanker or to the refinery itself.

Watch Crude Oil Transportation: 

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Crude Oil Distillation

This is the first processing of crude oil. In fact, oil is a mixture of liquid hydrocarbons (kerosene, gasoline gas) and to separate them, it is precisely the distillation, that is, a process involving vaporization and condensation. This is done in the so-called splitting column. The latter is a steel tower divided by so many "planes" made up of large steel plates. Each dish has its own specific temperature, which decreases as it goes upwards, and has various holes each fitted with a fireplace and a bell. 

The vapors of a certain type, when they touch the plate bell that corresponds to their condensation temperature, become liquid. The other gases continue to rise. More precisely in the dish at 300 ° C condensate the gas oil; in that at 250 ° C condensation of kerosene; in that at 200 ° C the virgin-naphtha; in the dish at 120 ° C the gasoline and finally at that at 60 ° C condensate the liquefaciible gases (propane and butane) and, in the higher part, lighter gases such as methane and ethane. 

From the bottom of the column comes the residue also called heavy oil. It can pass to storage tanks to be used as fuel oil, or again distilled and separated into two fractions: the paraffinic distillate (used to make lubricants or even to form gasoline through cracking) and the asphalt residue (bitumen or tar of oil). From the bottom of the column comes the residue also called heavy oil. It can pass to storage tanks to be used as fuel oil, or again distilled and separated into two fractions: the paraffinic distillate (used to make lubricants or even to form gasoline through cracking) and the asphalt residue (bitumen or tar of oil). From the bottom of the column comes the residue also called heavy oil. It can pass to storage tanks to be used as fuel oil, or again distilled and separated into two fractions: the paraffinic distillate (used to make lubricants or even to form gasoline through cracking) and the asphalt residue (bitumen or tar of oil).

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What is Heavy Crude Oil ?

Crude oil that does not easily flow at room temperature is called heavy crude oil. This differs from lightweight crude oil, which freely flows at the same temperatures due to its lower density. Crude with American Petroleum Institute with a density below 20 degrees is classified as heavy crude oil or heavy crude oil. It is said that the total amount of heavy oil worldwide is more than double the most traditionally used crude oil.

Heavy crude oil deposits are often found near bituminous sands, or bituminous sands, which are blends of sand, clay, water and extremely dense petroleum. From time to time, the term "bitumen", which is the sticky, semi-solid tar-like form of oil found in bituminous sands, will be used interchangeably with the heavy heavy crude found in such deposits. Some geologists argue that bitumen is simply a form of heavy crude oil that is so dense that it does not flow at all at room temperature.

Heavy oil transport and refining poses major transport environmental hazards and refining more traditional light raw oil. Heavy oil contains more carbon, along with many other impurities, then releases carbon dioxide during production and during use, which may adversely affect the Earth's ozone layer. The heavy oil production process can generate up to three times the amount of carbon dioxide that light generates oil production.

Economically, heavy crude oil is often a lower price than light crude because it is considered more difficult and more expensive to work. Although heavy oil is often at a much lower depth than light oil - a feature that can significantly reduce the cost of extraction - heavy crude production presents additional costs. Many of the traditional methods in force for the transport and extraction of light crude oil are ineffective when dealing with the heavy density of heavy crude oil, which requires expensive infrastructure modifications.

Since easily accessible light crude deposits diminish, heavy oil production has become more common. Even though it is located in more than 30 countries, larger deposits are found in Venezuela near the Orinoco River. These deposits are estimated to hold more than 500 billion barrels of oil, making them the largest oilfield recoverable in the world.

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