In Depth

Welcome to the "In Depth" section. This section is where you are finally going to see some actual work. So gather your wits and hold on fast...

Creation

In the beginning, the sun created the plants...

Oil is a fossil fuel - a fuel created over millions of years from decomposed organic matter.

When we drive cars the energy in the oil is released. This energy originally came from the sun, which was absorbed by plants. These plants were eaten by animals, who inherited the energy.

Many plants, a phenomenal amount of single-celled organisms, and, to a lesser degree, some animals, died and ended up at the bottom of large bodies of water, where layers of sediment were piled on top of them. They then spent millions of years decaying under the rock and, devoid of oxygen, formed fossil fuels.

Today we pump the decomposed organic materials out of the ground and use them for a variety of things - we owe most of our fuels, plastics, oils, bitumen, etc. to those dead organisms.

Drilling

Well, once the oil is created, it just sits there until we get our hands on it. But, how do we get it out of the bowels of the earth in the first place? As you may know, we get oil from oil wells, which are drilled into the earth to suck up all the oil. Here's how it's done:

An oil well is created when a hole of 5 to 30 inches wide is drilled into the earth, with an oil rig turning the drill bit. The hole is then cased in a cemented metal pipe to keep the hole from collapsing on itself. After that, one of two things is usually done: either the casing and cement are punched through with holes (perforated) to get to the oil (cased hole completion), or more earth is drilled beneath the casing (open hole completion).

Basically, this is how it goes:

• The drill bit breaks up the earth, which is removed, and makes the hole bigger.
• The drill string, which is a big metal pipe made of lengths of steel tubing screwed together, is lengthened as the hole gets deeper.
• More drilling and casing until the hole reaches the depth at which the oil people think that the oil is located.

Once the well has been made, it needs to be 'completed', which means making the well ready to bring up the oil. The perforations made in the casing allow the oil to flow through, but a small pipe (tubing) is also run into the hole to act as a conduit for the oil and gas. In the case of open hole completion, a 'sand screen' is installed to stop rocks from falling into the hole and blocking it.

After that, something called a packer is run down outside the tubing. Then, a multi-valved structure called the Christmas Tree is secured to the top of the tubing. The Christmas Tree is used to control the flow of oil into the well.

And that's how a well is created. To get the oil flowing, different things are done depending on what type of rock the reservoir is located in. For example, in the case of limestone rock reservoirs, acid is pumped down the well and through the perforations to eat through the rock and let in the oil.

Of course, a lot of other scientific stuff is involved in digging a well and extracting the oil, but these are pretty much the basics that you should know before we continue.

Note: Oil can also be extracted through offshore drilling, not only surface drilling. Offshore drilling is basically the same thing – drilling through the earth at the very bottom of the ocean to get to the oil – but requires a bit more work because of all the water, which can cause pipes to collapse.

Jargon:

Oil rig: A building used to keep equipment for drilling for water, oil, or natural gas. The rig isn't directly involved in extracting the oil; rather, its main function is to drill the hole for the oil well.

Drill Bit: The thing used to drill the hole, held by a drill.

Drill String: The lengths of steel tubing, screwed together to create a pipe.

Fractional Distillation

As you'll remember from the introduction page, the oil we pump out of the ground is called Crude Oil, and is not very helpful. It must undergo a procedure before it can be used as fuel, plastic, or anything else. The first step of this procedure is called Fractional Distillation.

Because longer hydrocarbons have lower boiling points, it is possible to separate hydrocarbons according to length by method of evaporation.

The shorter hydrocarbons that rise to the top burn the fastest and are used for fuels. The shortest ones are used for bottled gases, for camping stoves and the like. The ones that are longer than those ones and evaporate at 70°C are used for gasoline (car fuel), and the ones that are longer than them and evaporate at 180°C that are used for Kerosene, to power jet planes and kerosene lamps.

The hydrocarbons that evaporate at 260°C become Diesel and are used for larger vehicles, such as buses. Under that are the more viscous hydrocarbons that evaporate at 300°C and are used as lubricating oil for bikes and joints.

Under that are the hydrocarbons that evaporate at 340°C which are used as fuel oil for power systems. Finally, the longest hydrocarbons and the most viscous ones, are used as bitumen. The most common forms of bitumen are asphalt, for roads, and tar.

Fuel (Gasoline)

One of the most popular uses of oil is to make gasoline, to power our cars. Gasoline is produced in oil refineries and is made up of shorter chain hydrocarbons (typically molecules with five to twelve carbon atoms).

In oil refineries many things are blended together to make the gasoline we use, including, but not limited to;

• Natural Gasoline, the stuff that comes directly from distilled oil.
• Reformate, a very aromatic chemical with a very high octane rating
• Cat (catalyst) cracked gasoline, gas that has been "cracked" in a catalyst cracker.
• Hydrocrackate, a cracked form of gasoline that has been "cracked" in a hydrocracker.
• Alkylate, a very clean-burning chemical with excellent "antiknock properties".
• Isomerate, a hydrocarbon that has had its "octane rating" boosted by method of isomerization.

Jargon Buster:

Octane Rating: Represents the "antiknock" properties of the fuel. The higher the rating, the slower the fuel burns and the less likely it is to "knock".

Engine knocking: Caused by extremely flammable fuel burning too quickly. The resulting explosion causes a huge increase in pressure in the combustion chamber and can eventually damage or destroy engine parts.

Cracking: Because there is so much demand for shorter chain hydrocarbons to run our cars, some of the longer hydrocarbons are "cracked" - broken down into shorter molecules. A popular method of doing this is by method of "catalytic cracking", where the hydrocarbons are passed over heated catalysts where they thermally decompose and break down.

The gasoline is then taken from the refineries and sent out to "gas stations" where customers pay an ever-expanding price fop it. It is then burned and releases carbon dioxide into the air.

Alternative Fuels

There are other fuels that can be used to power automobiles as well. Some of them are more efficient, some of them are better for the environment. Most of them aren't very popular. Here is a list of the most common ones:

Diesel: Diesel is one of the most popular alternatives to Gasoline. It is 18% denser than gasoline.

Biodiesel: A renewable alternative to gasoline and diesel, whose production is growing rapidly throughout the world.

Ethanol: A renewable fuel derived from organic matter. Ethanol as a fuel is very popular in Brazil.

Hydroden: A natural gas that can be both burned and put into fuel cells.

Methane: Methane is another hydrocarbon. When the micro-organisms, plants and animals decay they let off the simplest hydrocarbon into the air – methane. It makes more energy than any other hydrocarbon per gram, and is important for generating electricity. We don't have to drill for it, our landfills produce it at no extra charge, but like all petroleum we don't have mountains of the stuff. That and it's a gas that contributes to global warming.

Methanotrophs really likes methane though, seeing it's their only source of energy. Bacteria is crazy.

Plastic (Tires)

In Which Petroleum Is Used To Make Rubber, and Rubber Is Used To Make Tires

Rubber is an elastic hydrocarbon polymer, which is found both in nature (in the saps of certain trees) and can also be produced synthetically. Synthetic rubber is made by polymerizing a variety of monomers (a molecule that can be chemically bonded to other monomers, thus creating a polymer) including isoprene, butadiene, chloroprene, and isobutylene – and these chemicals come from the residual oil, once its been processed.

It is also worth noting that there are different types of synthetic rubber than can be made by putting in varying quantities of certain polymers, which affect the rubber's physical, mechanical, and chemical properties. In turn, the different types of rubbers are used for a variety of uses, such as the following:

Molded rubber: Tires, hose, plumbing fixtures, gaskets, mechanical seal, mechanical belt, garden hose.

Sheet rubber: Inflatables (such as boats and toys), diving suit, boots, radar absorbent material.

Foam: Mousepads, orthopedic braces, wetsuits, balaclavas.

Tires!

Since tires are related to cars and cars are an integral part of the process of processing oil, let's focus on tires! The tires we use today, air-filled ones, are called pneumatic tires, are made with a bunch of different things – the bead bundle, a loop of extra-strength steel cable; the body, made up of layers ply fabrics; the belts, made of steel to reinforce the area under the treads; the sidewall, to provide stability and protect the plies; and more – but what really makes a tire a tire is…rubber!

Natural rubber is unsuitable for most of the tire, so we use synthetic rubber. This rubber is used inside and outside the tire: the bead bundle is coated in rubber, as are the ply fabrics used for the body. And, of course, the tread is made of rubber. The tread is actually made with a mixture of natural and synthetic rubbers, and is the outer coating for all the other stuff.

A tire, once all its pieces are put together, is still not ready to be used until it has been vulcanized. Vulcanization is a process that was invented by Charles Goodyear (yeah, the tire dude!) in which the tire goes into a curing machine, which heats everything up to bond it together securely, as well imprinting the tread markings.

So…there you have it! Now you know how the residue of processed oil is used for rubber, and how rubber can get turned into tires, which are a part of the process of processing oil.

Asphalt

So we have the tires, we have the fuel, but the road? Asphalt! It’s the super long hydrocarbon everybody loves to drive on! Approximately 80% of the asphalt in the US is used to pave roads. It’s used for some other obscure things, such as for cattle sprays, but mainly it’s roads and shingles.

Asphalt is sometimes confused with tar. And bitumen. It’s no wonder, people use them interchangeably, but in science we love to appreciate the differences. Like scientists fighting over whether evolution was a steady change, or was an erratic staircase of plateaus and sudden change.

• Bitumen is a category of hydrocarbons as dubbed by the Romans. Asphalt and tar are the most common forms of bitumen.
• Asphalt contains mostly bitumen, but is mixed with solids such as concrete, sand and rock to make it even better to drive on. It’s black, sticky, and highly viscous.
• Tar is usually a byproduct from the processing of coal, but it can come from petroleum with a lot of processing. It used to be involved in the creation of roads, but asphalt works better so we stopped using it. It’s black, sticky, and highly viscous.
• Pitch is a word that can be used to describe any liquid so viscous it appears solid, like bitumen, asphalt and tar.

So how does asphalt get to be a road? First of all, the company building the road has to have a stockpile of materials – equipment, asphalt, manpower, aggregate. Aggregate is made off the site of the main road by crushing up rocks into the appropriate size, and is the foundation of a good road. Aggregate is a fancy word for small solids in a composite material made so it can take more compressive stress of being driven on by loads of big vehicles.

Meanwhile, on site, earthmoving vehicles are giving the rough shape of the job. The ground is compacted and brought to the right height with road-base materials, and tested for density, and then any concrete (i.e. sidewalks) can be laid.

The sidewalk is in place! The ground has the right height, density, temperature, moisture content! Of course, it doesn’t need to be right on place, because the asphalt is mixed to take that into consideration. The asphalt is heated and mixed with the aggregate, oil and other additives.

Like making a meal where everything comes out the right temperature at the right time, the workers have to shuffle. If it cools too much on the way there, it can’t be laid, and if it cools too much right after it’s laid, it can’t be compacted. A bunch of trucks taking turns ensure it goes well.

The asphalt cools, and a new road is born. All hail petroleum.