Fossil Fuel Formation: Oil and Natural Gas.

Fossil Fuel Formation: Oil and Natural Gas

Oil and natural gas undergo a different process of fossil fuel formation compared to coal. These two substances tend to occur together and the process for forming them is the same. As with coal the formation conditions need to be very specific.

Oil and natural gas are formed from the remains of tiny aquatic animals and plants. As with coal, vast quantities of these organisms are required to make a viable deposit of oil or gas. These organisms, once dead, would have sunk to the bottom of the body of water they were living in, been covered in silt and mud, and then started to decay anaerobically See the description on the formation of coal for the difference between aerobic and anaerobic environments and their effect on decay.

As such, it is reasonable to assume that the bodies of water that these micro-organisms were living in were fairly stagnant, as strong currents in water both improve aeration and prevent the laying down of very thick layers of organic material in the one location. The image shows an algal bloom in a stagnant waterway. See the vast quantity of organic material that can be produced in a short time. With no current to sweep away the dead organisms, a thick layer of debris would quickly build up at the bottom of the water body.

The anaerobic decay of these micro-organisms means that while their cellular structures break down, the carbon chains that are the foundation of their bodies do not. As with coal formation time, pressure and heat drive out other substances such as water leaving mostly the carbon chains behind.

The carbon chains that are in crude oil are different in character to those in coal. Coal contains large strings of carbon rings with 6 carbon atoms in each ring. These are heavy and stuck together well, making coal a solid. The carbon chains in oil, on the other hand, are shorter than those in coal and are usually straight, maybe with a few branches. This is an approximate representation of the difference between coal and oil:

Fossil Fuel Formation: Comparing Coal and Oil Structures.

Coal contains massive molecules of carbon rings. These are from the plant fibres which can be very long, sometimes metres long or more. They also are often twisted around each other giving added solidity. The carbon chains in oil are tiny by comparison. They are the structural remains of microscopic organisms and so they are ALL very small, though there is a great variety within any crude oil sample. It is this the relatively small molecule size and the chemical structure of the carbon chains in oil that make it a liquid.

Natural gas such as methane is merely the tiniest pieces (fractions) of the oil molecules. These are so small that they do not stick together well enough to be a liquid, and so they are gaseous. For this reason Natural Gas is almost always found with crude oil. Natural Gas can sometimes be found on its own (meaning only the tiniest molecules of oil were formed). Oil is always accompanied by some natural gas. Rather than go into a long discussion I will use a series of pictures of the fossil fuel formation process for oil. Here is a scene of the lake or shallow sea with an algal bloom on top:

Since algal blooms are often toxic to animal life in the water body, it is reasonable to assume that at least some of the oil comes from animal remains.

Next the dead matter is covered with silt and mud. This silt and mud eventually compresses into rock, leaving the organic material trapped between two layers of rock:

As more silt and mud is laid down, more layers of rock are added on top of the organic matter layer. Volcanic activity may also be adding extra layers of rock on top of the organic layer. This is taking millions and millions of years. The extra weight of the rock as well as some heating from beneath the crust of the earth are helping to drive water out of the oil-to-be. NOTE: the reason the rock layers are not flat is because they are being pushed sideways as well as down. This is coming from the movement of the tectonic plates that make up the earth?s crust.

So after a while the organic material is looking quite oily, and may find itself in a situation like this:

Let?s assume now that the organic matter has been squeezed and heated enough to break it down into something resembling crude oil. Since it is now in a liquid state, the crude can move.

How does oil collect in vast amounts but in small areas?

It might seem reasonable to conclude that there should be a thin layer of oil spread thinly in the majority of places. However, crude oil and natural gas are concentrated in large deposits in some areas but are absent in others. Why?

This last step of fossil fuel formation involves porous and non-porous rock layers. A porous layer is one that contains lots of little holes in it, like a sponge. Basalt, a volcanic rock formed from rapidly cooling lava, is one such rock. Non-porous rocks do not have these holes in them, but are solid.

The oil seeps upwards through porous rocks as a result of the great pressure of the overlying layers. It does this until it hits a non-porous layer, and there it collects, like so:

Fossil Fuel Formation: Predicting Locations

Geologists are able to predict probable locations for oil from examining the structure of rock layers and then test-drill in likely areas. Not all probable locations contain commercially viable oil reserves. Some locations will have no oil or gas, some will have tiny amounts, and yet others will have the oil present but still trapped inside porous rock layers such as oil shale. Only the areas where large reserves of liquid oil are present are generally commercially viable to drill. These locations may be on land or under the sea. The earth?s crust plates are constantly on the move, and the oil reserves move with them.

The reason a lot of the oil drilling occurs at sea is simply because the majority of the crust of the planet, under which the oil is located, is covered by water. It is a testament to our dependence on this source of fossil fuel that it is economically viable to go to the extreme trouble and expense of building and maintaining these structures.

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Fossil Fuel Power Plants: how Electricity is Generated.

Fossil fuel power plants produce the electricity which is the lifeblood of the developed nation, and we all rely heavily on it in our daily lives. The majority of current power stations run on fossil fuels. While solar energy power stations are being developed around the world on commercial scales, it is true to say that over 70% of every developed nation?s energy comes from fossil fuel electricity generation. In Australia, over 90% of our electricity is sourced in this way.

Power stations supply the main energy grid with electricity on-demand; that is, the greater the demand the more the power stations churn out.

That means that the greater the demand for electricity, the larger the amount of coal, oil or gas the fossil fuel power station will be consuming. A clear explanation of how the power stations turn fossils into electricity is in order.

An iron bar is made of lots of tiny iron crystals. When all these crystals are aligned, the iron bar will produce a magnetic field. Compasses are tiny magnets that align with the earth?s magnetic field. Have a look at this simple experiment in which you can make your own compass. Early compasses were simply lumps of magnetic iron-rich rock called lodestone.

Why iron does this and many other metals cannot is due to the arrangement of electrons in the d-subshell of each atom. Discussion of that topic is beyond the scope of this website.

It turns out that the magnetic field of a bar magnet looks something like this:

Those lines around the magnet are the FORCE LINES; they make up the magnetic field. Those field lines are able to push free electrons around so that they align with the field lines.

If we make a coil of copper wire and push a magnet through it quickly the electrons will move in one direction and you will have a current. Copper is used because it conducts really well, but any metal can be used for the wire. The reverse is also true; if we push electricity through a copper coil, it will generate a magnetic field. That is called an electromagnet. Electromagnets usually have an iron core to improve the magnetic field.

Now if we take one electromagnet and spin it inside another coil, the field from the electromagnet will create a current flow in the second coil. This is because the magnetic field pushes the electrons in the second wire coil.

Just like any other electrical device, the turbine needs to be connected to a circuit to allow electrons to flow in a loop. The electricity grid that the turbine is connected to is one enormous loop.

Now we have a spinning turbine causing electrons to be pushed out into the loop with some force, the force given to them by the magnetic field. The faster they are going the more energy they have and so the more work they can do for us in our homes.

This is where the fossil fuels come into the equation. Energy is needed to turn the turbine, and that energy needs to be harvested from somewhere. Possibilities include wind, falling water, waves, or steam. Traditional power stations use steam.

The coal (or oil or gas) is burned in a furnace. The furnace heats water in a boiler. This generates super heated steam that turns turbines. The steam is then cooled in cooling towers and condensed back into water to be returned to the boiler, reducing heat loss as much as possible. Some steam has to be released in the cooling process; that?s the source of those big white clouds coming out of the power station cooling towers. Here?s a picture of the process:

The exhaust gases are also used to heat the boiler chamber before being released via the chimney stack. This is where the environmental nasties such as CO2, NO, SO2 and ash, called fly ash, are released into the air.

The amount of coal going into the boiler, and therefore the amount of Carbon Dioxide and other gases being emitted from this fossil fuel power, is determined by our actions. We can reduce the amount of pollution from the power stations by using less electricity.

While we are still operating the majority of our power stations as fossil fuel power plants this is crucial; lower energy demands mean less pollution.

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Fossil Fuels or Solar Future? We must choose carefully.

Recent reports on the current status of the reserves of fossil fuels point to a the need to switch to alternative energies such as Solar Power. The thinking behind our current economic policies has driven an exponential increase in our energy usage over the last 100 years. Unfortunately, the worldwide reserves of oil, gas and coal are limited.

Even without considering environmental impacts, it is clear that at some stage we will not be able to meet our ever increasing energy needs from a finite supply of these non-renewable resources.

To gain the best understanding of how to address our dependence on fossil fuels we need to be fully informed. Follow the links for more background information - with knowledge we can make informed, intelligent decisions that give all of us and the planet the best results.

The processes that have lead to the formation of coal are different to those that produced oil and gas. There is also a body of evidence that suggests abiotic oil formation, which has significant implications on the current state of our estimated energy reserves. Find out about the conditions required for the formation of these essential energy sources, and how the fractional distillation of crude oil turns the raw material into useful products. We all take for granted filling up the car or turning on the television, but where does the fuel for these come from? Different sources of fossil fuels need to be extracted according to type and location. We all use electricity every day, and now we can have the facts on how it is generated. Understanding how fossil fuel power stations generate electricity is important if we are to have productive discussion about this at both the personal and governmental levels. Take a look at what happens on a chemical scale when burning fossil fuels. Follow the journey of a simple methane molecule all the way to its transformation into the undesirable Carbon Dioxide.

There are other issues associated with combustion of fossil energy sources. Smog air pollution is a significant health risk to those living in built up areas and despite some measures to improve the situation, photochemical smog continues to pose noticable health risks to city dwellers. Carbon Monoxide Pollution is produced from incomplete fuel combustion and can be detrimental to health even in low doses.

Different types of engines also contribute to either clean or dirty emissions. Four stroke engines are by far the most environmentally friendly version of the internal combustion engine and are used in almost all cars in service today. The two stroke engine is a popular choice for smaller applications, but the 2 stroke exhaust gases are a serious cause for concern.

LPG has been touted as a good replacement for gasoline, with many governments now keen to reduce their dependence on oil supplies, particularly those from outside the country. What about its environmental credentials though? Is it really an alternative fossil fuel? Find out here. There is a fair amount of hype on the internet about using water for gas in automobiles. Find out the facts behind the hype. Learn about the structure of the H2O molecule and how hydrogen electrolysis of water can give perfectly clean fuel.

At the same time we need to be aware of the numerous scams that pop up surrounding potential fuels. One term used to refer to water is dihydrogen monoxide, a fancy title for a common substance.

There are significant advantages of fossil energies for developed countries to continue using these energy sources. The existing infrastructures and economies of most developed nations can at present only survive with continued consumption of fossil energy. Will the supplies of fuels we use today come to an end? Fossil energy sources by their very nature are a limited resource, though some are far more abundant than others.

There is a lot of discussion about Peak Oil facts and global oil production. Are the reserves about to run out, and how do recent discoveries like the Bakken Oil Field change this outlook? Also, what are the prospects for the development of other fossil sources such as oil shale and oil sands?

The trend in Australian petrol prices is a reflection of the global rise in oil prices. What, if anything, can be done about this situation? We also need to consider the impact of these prices on us both personally and also as a nation. It is also important to keep in mind the principles behind economic growth and the effect our individual attitudes can have.

There has been a lot of talk about it, but can Clean Coal live up to the hype? Find out how this experimental technology works and its possible impacts on global greenhouse emissions.

There are also many varieties of petrol, or gasoline, available for use in vehicles with different Octane ratings. Some of these are supposedly better than others, but what is Octane and what does the rating on the pump really mean?

Find out how the much discussed Carbon Dioxide contributes to global warming, also known as the Greenhouse Effect. Understanding the science behind the discussion is an essential motivator for sustained reduction in personal emissions. It's a burning issue in the minds of all of us. What will the impacts of global warming be on us and our children? Nuclear powered reactors are capable of producing vast amounts of electricity with no greenhouse gas emissions, which is clearly a great benefit given current concerns about climate change. Find out how a nuclear fission reaction allows us to produce this power, and how a nuclear power plant works.

What are the dangers of this energy source, and how likely are large scale catastrophes from malfunctioning nuclear power stations? Also find out what fuels are involved in nuclear power stations and what the term enrichment means in Nuclear Power Information: Fuel Preparation.

Plastics and Oil

Our need for energy competes directly with our requirement for modern materials. We have become heavily dependent on plastics in everyday items that are both re-usable and disposable, meaning that our dependence on oil goes well beyond fueling our cars. Find out about plastics raw materials, how plastics are produced, which ones can be recycled and more.

The information leads us to the unavoidable conclusion that we must find alternatives to both our uses of fossilized fuels and our approach to energy use. That last one is uncomfortable, but I have been working some Government energy use statistics in a spreadsheet program and this is what I've got so far:

This graph depicts past, current and projected energy use based on a consistent 3.3% increase in annual electricity usage. We can see that the amount of electricity we will be using will continue to rise. This is not unreasonable; more and more of the objects we use in our daily lives require electricity and this trend will continue.

A constant rise of 3.3% in energy use may not seem like a lot. It is important to realize though that this is the same as accelerating in a car. Even if we only accelerate a little bit, over time we will end up going ridiculously quickly. Here is that same graph again, but this time projected into the future, up to the year 2200:

It keeps going up exponentially; have a look at the units on the vertical axis; they are quite a bit higher than in the current graph shown first. Clearly this is impossible to sustain. Yet the trend continues and has done so steadily for some time.

It is quite clearly impossible, since by 2200 we would need to cover almost the entire land surface of the planet with solar panels just to provide Australia with its energy needs, which represents a meagre 0.33% of the global population. Were all countries as high in their energy needs as Australia, we would need 300 earths completely covered in solar panels to provide us with the energy we would need.

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What Other Visitors Have Said

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I find that having a laugh at things like our energy use helps lighten the load. We are all intelligent people, and surely together we can come up with a solution. We can't afford a doom-and-gloom approach. I like Fred's poetic humor site; good for a laugh if it gets too serious.

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