Published on EGEE 101: Energy and the Environment (https://www.e-education.psu.edu/egee101)

Home > Lessons > Lesson 7: "Black Gold...Oil That is...Texas T"

Lesson 7: "Black Gold...Oil That is...Texas T"

Overview

Many people think of Texas when they think of gushing oil and drilling rigs, but Titusville, PA., in the northwestern part of the state, lays claim to the first operational oil well in this country. So, the oil industry has its roots very much in our backyard.

Thus, this lesson deals with the origins of oil and natural gas. Please watch the following (0:35) introductory video:

Dr. Mathews, caught on video spending a cold, wet morning with a stripper.
Click for a transcript.

[Dr. Mathews is standing in front of a nodding donkey (oil pump) on a cold and rainy day.] Dr. Mathews: Today's lecture is obviously about crude oil. I am just south of Pittsburgh. It is bloody cold. But this is a prime area for producing Pennsylvania’s lifeblood, crude oil, and natural gas. This one behind me is pumping, so it's probably not flowing out of the ground anymore so there is probably not any associated natural gas. [Dr. Mathews walks off the scene and we are left looking at the oil pump.] [Video ends]

Lesson Objectives

Your learning objectives for this lesson:

  • Explain how oil and natural gas is formed, found, and extracted (this also includes shale gas)
  • Discuss environmental implications of extraction
  • Articulate oil quality issues
  • Demonstrate knowledge of oil shale and tar sand formation and extraction
  • Explain reserve-resource transformation issues

Wake Up Your Brain

Question: Are fossil fuels beneficial to Pennsylvania?

Yes
No


Click for the answer.

ANSWER:
We have relatively cheap electricity and cheap natural gas. Our oil production (mostly in the NW portion of the state [1]) produces high-quality crude oil and lubricating oils. Shale gas has causing an energy revolution. We have employment opportunities and contributions to the economy. However, we have a legacy of environmental damage. Even though our extraction process is much better than it was in the 1970's we continue to live with the balance between the production of energy and fuels, along with what is acceptable to the environment while not making the energy or fuel too expensive. We will see renewables are advancing, but we cannot yet provide all of our transportation needs with renewable energy. So, "beneficial but with a cost" would be my answer.

Crude Oil and Natural Gas Formation

Often when we find crude oil we also find associated natural gas. The natural gas provides much of the pressure to produce the "blow-outs" that in good old days (and in the movies) signified an oil strike. We can also find natural gas alone without crude oil. The gas has migrated away from the crude oil, or perhaps the oil has "seen" a high enough temperature that it has all been converted into natural gas.

As organic material decays, methane is formed and lost into the atmosphere. As the organic material breaks down, depending on the inputs (trees vs. plankton), the different fossil fuels will form. As the material is buried deeper the temperature increases and there is an "oil window", or an opportunity to find oil. If the temperature is too high then all the crude oil will form natural gas instead, and so the oil window closes. Of course, we also find oil at the surface, but this tends to be degraded oil that has lost the more volatile components and so tends to be tar pits (not pools of crude oil).

 Graphic of the oil window. Fully described in two paragraphs above.
Changing processes of maturation that occur with depth (and temperature): Diagenesis, Catagenasis, and Metagenesis.
Credit: Louisiana Department of Natural Resources

The Carbon Cycle - Revisited, Again

The phytoplanktons [2] are numerous in the ocean and are a very significant portion of the carbon on the earth. They live in water near the surface during life and use the solar energy in a similar manner to plants on land to store chemical energy. They tend to be concentrated in nutrient-rich zones. As the first link in the ocean food chain, they are eaten in large quantities.

Phytoplankton growth illustration.
More phytoplankton growth
Drawing of sunlight shining on the ocean. Little green spots representing phytoplankton growth.
Phytoplankton growth thanks to photosynthesis

Death

Upon death they sink to the bottom of the ocean where the decay process occurs. Think back to all the deep-sea footage you have seen where is it "raining" organic matter. Often the nutrient-rich zones are also locations by rivers that carry sediment from the land to the sea. If the dead plankton and sediments fall in quantity they will form an organic-rich layer at the bottom of the ocean. There it will be protected from aerobic decay, because of the physical protection (sediment) and the lower oxygen content.

 Drawing of sun shining on the ocean. The phytoplankton is dying but is still on the surface of the water.
Phytoplankton dying but still on the surface of the water.
 Drawing of sun shining on the ocean. The phytoplankton is dead and it has sunk towards the bottom of the ocean.
Phytoplankton dead and sunk to the bottom of the ocean.
 Drawing of sun shining on the ocean. The dead phytoplankton is lying on the ocean floor.
Dead phytoplankton lying on the ocean floor.

Maturation

Over long time periods, millions of years, the layers are buried deeper and deeper and the temperature builds up (as does the pressure) and the layer turns into a rock. However, it is a rock that has significant organic content. Additional time, temperature, and pressure, and the maturation process produces kerogen. Additional time and the kerogen is transformed into bitumen and then crude oil with associated methane. These materials can escape the source rock and if unchecked can seep into the surface of the ocean (or land) and decay back into carbon dioxide and water.

Structural Traps

As the oil and natural gas move through porous rocks, if it meets an impermeable layer, then it is stuck and the maturation process continues. Thus, crude oil and gas "live" within porous rocks, not great holes in the ground (unless they are in the strategic petroleum reserve) - more on that later.

Extracting Oil

If we find these structural traps and they contain oil or gas, we can extract the fossil fuel and much of it will be combusted to generate thermal energy (for transportation or heat) and yield carbon dioxide and water.

 Drawing of the sun shining on the ocean. The dead phytoplankton is soaking into the porous rocks on the ocean floor.
Drawing of the sun shining on the ocean. There is an oil rig extracting the oil from the porous rock on the ocean floor.

How do we know crude oil is from phytoplankton (and other organic material)?

When we extract crude oil it contains some water. However, even when we extract Pennsylvania crude oil the crude will still contain water but it is NOT often fresh water. The water contains salt and many of the other elements in concentrations that we find in the ocean. The disposal of this salt water is an expense. In the good old days, it was thrown in a river or stream but the salt would kill the fresh-water fish. Now it is cleaned prior to disposal although we hope that PennDOT and PA DEP (Department of Environmental Protection) will let us dispose of the salt water on the winter roads to prevent icing.

We also find microfossils in the source rock that indicate that the inputs to the rock contained life. However, the strongest indication is the identification of biomarkers within the crude oil.

This branched C17 (hydrocarbon containing 17 carbon atoms) is an isoprenoid, and is a chemical we can extract from plant life.
A Porphrin ring.

The Porphrin ring has an important role in biology. The nitrogen atoms are blue in color and there is a metal ion (in this case vanadium) in the center of the molecule. Metals such as vanadium and nickel are present in oils at low levels but they are important contaminants. Nitrogen as shown is blue, double bonds are not indicated. This is an example of a porphrin ring a biomarker in oil. The metal sits in the central location of the rings. If catalytic cracking of the oil is performed, it is important to remove these metals as they poison the catalyst. Vanadium can be recovered from the ash or flue gas when high vanadium containing oils are combusted. The vanadium can then be sold to the metals industry for use in steel generation. Biomarkers are also useful for identifying where the crude oil is from.

The Search for Crude and Natural Gas

As we have already seen, we use lots of crude oil. So to prevent it from running out we look for more crude oil. We can go around drilling holes but it is an expensive operation and so we only drill if we think there is a good chance of finding crude oil. Even then dry holes are not uncommon. There needs to be a certain set of circumstances for us to find trapped crude oil. Of course, oil and natural gas are finite resources so we will run out eventually.

magnifying glass looking at an oil rig
 
Credit: EJS

Source Rock

When the zooplankton and phytoplankton died and fell to the ocean floor, sediment helped bury the organic material. Over the maturation process, the sediment is transformed into rock and we use the term source rock for this material. Finding it is a good sign that oil might be nearby. Within this rock, we can find microfossils, and along with biomarkers, it is good evidence that oil was created from organic material. The source rock indicates where the oil was when the kerogen to bitumen to crude oil transformation occurred the crude can escape the source rock. So now the challenge is to find where it might have gone.

Structural Trap

The crude oil and natural gas can travel through porous rocks. If there is nothing to stop it, then the crude oil will reach the surface and eventually degrade (recall the oil spill page - one approach to cleaning up an oil spill is to do nothing - it is a natural material and there are natural processes to destroy it, although this approach does not work well if the spill is large or close to sensitive areas!) We call these locations where we find crude oil (or natural gas) at the surface seeps. A seep is a good indication [3] of crude oil underground. However, often the material at the surface has lost the light ends (compounds with low volatility) and are not very valuable. Thus, we need to find structural traps where impervious layers prevent the crude from progressing any further. Examples of structural traps are: salt domes (the SPR is kept in large salt caverns "drilled" with water to dissolve the salt), faults, and anticline folds.

Reservoir

A structural trap does not do us any good unless there is a porous rock that can hold lots of crude oil. The idea that we drill down into "lakes" of crude oil is a fallacy - we drill into a porous rock and the pressure of the crude oil and associated natural gas pushes the oil out of the ground.

This PDF file provides very good information about how crude oil is found and the technologies that are utilized [4] to find and extract the crude oil. Ensure you look it over.

One thing you'll become familiar with is the use of seismology in the search for crude oil and natural gas. Below is a movie captured from a software program called the "Seismic Duck", which, via an animated sequence, shows how seismic waves are used to detect oil sources deep in the ground. If you've ever seen ultrasound technology at work, a similar principle is at work. Please watch the following (:44) video.

What's a duck have to do with oil? That's what we'd like to know.
Click for transcript.

[Animation opens with a duck sitting on top of the earth's crust. Under the crust is a thick layer of sediment. Then there are three natural gas and oil deposits. As the animation goes on, sound waves are shown to emit from the duck and detect where the oil and natural gas is located. Once found, it is drilled into.] Dr. Mathews: When we talk about seismic waves what we are doing is setting off an explosion, or actually an air can, we don't tend to use many explosives. And it is the sound waves that propagate through the sedimentary rock, and they bounce back. And by having a whole multitude of sensors we can determine a good picture of what underlies the ground. And once we do that we have a good idea about where the structural tracks are. We can go ahead and drill down. Now in this situation, there is a porous rock shown containing water, which is the blue line. So we are going to drill down to extract the crude oil and the natural gas. You don't extract all the natural gas because it is helping push the crude oil out. And of course, at the same time, we are also getting water as well. [Animation ends]

 

Reserves and Resources

There is a very important distinction between resources and reserves, which is illustrated in the image below.

Move your mouse over the "oil areas" to see how crude oil resources, reserves, and consumption relate to each other.

Fuel Resources are fuel formations that are known to exist but are not currently economically viable (or technologically viable).

Fuel Reserves are fuel formations (such as an oil field) known to exist, which have fuel that can be extracted economically with current technologies and price structures. When oil prices rise or there is an advance in technology (such as deep sea oil drilling or hydrofracking), then resources become reserves, etc. Of course, new oil (coal and gas fields) are still being found. They are also still being formed but the rate of formation is so slow (millions of years) we do not consider new fossil fuel formation a possibility.

So we have extracted a lot of our fossil fuel resources but there are many more available as you can see below. Unfortunately, it tends to be lower quality and more expensive to get.

Oil pyramid showing quantities of reserves and resources.
Oil Pyramid.
Credit: U.S. Congressional Research Office

Crude Oil Lifetime Reserve Calculation

The lifetime of a fossil fuel is the quantity available (reserve) divided by the consumption. So:

Lifetime of a fossil fuel = Quantity in Reserve/ Rate of use

Let's look at some numbers:

  • Total US proven reserves of crude oil are 22,446 million barrels.
  • Estimated production/extraction (would be the better term) is 1,915 million barrels.

Lifetime of supply calculation:

22,446 million barrels / 1,915 million barrels per year = ~12 years

Why doesn't this worry me [5]? Audio Text Version (click to reveal)

Dr. Mathews: You would think if we only had eleven years or twelve years supply of crude oil left that we should be in a bit of a panic. But the bottom line is that we aren't. If I looked up the data from a few years ago, actually we have more crude oil than we did back then. Remember this is somewhat of a misleading calculation. Because although we do have a relatively fixed quantity of crude oil in the world, our ability to find it changes quite dramatically, in the sense that we have to be looking for it. When we have lots of reserves and the price of crude oil is low we don't look for it. When we have certain economic indicators that the value of crude oil is higher then we go and look for some more. And so it is a continually moving target. Yes, we have crude oil. Yes, we use it. But the bottom line is we do not see reductions in how much crude oil we have every year. This is because we find new crude oil. This is because of some uncertainties in the existing fields. And we tend to be able to make some adjustments and get some more out of the ground. And if you look back in the history of these estimates, even one-hundred years ago, said we had thirty years to fifteen years of a supply of crude oil. And every decade or so someone comes up with the same calculation and the same estimate and the number is about the same. So we have had about a fifteen year supply of crude oil for the last hundred years. And we are probably going to have a fifteen year supply of crude oil well into this coming century. Now certainly some of our fields are going to become exhausted. Some of the Alaskan fields, for example, are going away and in the UK, some of the North Sea fields are going to be exhausted. But essentially what we will do is look for new crude oil. We will spend additional money, we will have new technologies, we will go deeper finding it in the Gulf of Mexico, and we will be able to extract more with some additional techniques I will discuss. So yes we only have eleven point two years of crude oil supply via this calculation but the reserves are going to continue to grow and be depleted at the same time. Generally, that is going to be about the same rate. But eventually, at some point in time, the US is going to pretty much run out of its crude oil but then we are going to switch to other fuels. Remember we can take coal and turn it into a crude oil. The reason we don't do that is because it is expensive. Cost us about thirty-five dollars a barrel to that and I can go and buy a barrel of crude oil for about twenty-seven dollars. So it is cheaper but once we start running out, then the cost will go up, and we will be more able or be more intent to save money by going with some of these new advanced techniques. And of course there are tar sands, oil shale, and the list goes on.

Here is a good example of how changing technologies such as horizontal drilling and hydrofracturing have recently (2008 to 2012) increased our reserve even while our Alaskan reserves are being depleted due to extraction.

U.S. crude oil and lease condensate proved reserves, 1982-2012.
U.S. crude oil and lease condensate proved reserves, 1982-2012.
Credit: EIA

More Fossil Fuel Lifetime Reserve Calculations

Natural Gas

We can do a similar calculation for US natural gas:

  • Total US proven reserves of natural gas are 21 trillion cubic feet.
  • Estimated production is 19,779 billion cubic feet per year (this varies with weather, economy, etc).

A lifetime of supply calculation:

183,460 billion cubic feet / 19,779 billion cubic feet per year = 10 years

Coal

  • We have in the neighborhood of 261 billion short tons US reserves (recoverable coal).
  • We mine (and use) about 1 billion short tons.

That equates to about a 261-year supply if we maintain coal extraction levels.

Remember, our RESOURCES of fossil fuels (those that are not economic to extract, or which would require technology we currently lack) are much larger than the reserves (that we can extract using current technologies and are economically viable).

Extracting Oil and Gas

 Equipment preparing to drill for oil. Details in caption.
After all the technology, there is still only one way of ensuring that there is crude oil or natural gas at a particular location, and that is to drill. We don't just drill holes! There has to be drilling mud to cool the bit, and a pipe so there is no contamination of the local water table. This image shows a bulldozer for building the road and bringing in equipment. The drilling rig with spare pipeline, concrete mixing, and well-logging trailer.
Credit: Dr. Bob Watson, PSU

There is only one way to tell if the location you have picked contains any oil or natural gas: drill! This is one of the most expensive parts of the extraction process and there is a lot of technology employed in selecting the location and technologies employed. In the "good old days" a wooden platform (a derrick) would have been built to enable the drilling process. Roads are often built to allow the machinery into the appropriate locations, machinery, equipment, and pipes that will be used at the site. Not to mention the storage of the crude (or natural gas) and the extraction and storage of the saltwater. The drill bit rotates and chew's into the earth. If you have seen Armageddon (Bruce Willis drilling into an asteroid) you know that drilling is both an art and a science. There is lots of friction and heat so it is necessary to cool the bit with drilling mud. In most cases, there will also be a need to enclose the circumference of the hole with pipe to stop it collapsing. As the hole gets deeper more casing is added. Eventually, there is a pipe going deep into the earth. Sensors attached to the drilling system alert the operators to when they reach the desired position and if there is any "black gold" (or natural gas or both). It is undesirable to let the oil burst out of the ground because you lose some of the reservoir pressure (that pushes the oil out of the ground). A production pipe is lowered and concrete poured to fill the gap between the production pipe and the enclosing "pipe".

Picture of a piece of stainless steel pipe with several holes in it.
(left) This stainless steel pipe is large but clearly shown are the many perforations created by a "bullet" shot from the inside out to allow the oil to flow into the pipe. (right) A close-up of the bullet hole.
Credit: JMP

Now we have a deep hole in the ground. To allow the reservoir (the oil-bearing rock) to make contact a perforation gun is used to "shoot" a hole through the production pipe. There are also techniques used to frac (short for fracture) the oil-containing rock so that production can increase the flow of oil out of the ground (recall lesson 4!). If there is associated natural gas with the oil then the oil will flow out of the ground. Unfortunately, in many of the PA wells and at other locations this does not last and the reservoir pressure drops and the remaining crude oil (that is extractable) has to be pumped out of the ground.

A labeled sketch of a horse head crude oil pump used to pump crude oil out of the ground.
Horse head pumps.
 

The horse head pumps pump the crude oil out of the ground. If you need more crude oil then drill another well, situate it close to an existing production well so you expect to find crude oil, and add another pump (horse head). In PA we have lots of these stripper wells (a well that does not produce more than 10 barrels of crude oil in a week). Being English I know these horse head pumps as "nodding donkeys".

Extraction and Production of the Crude Oil

Chemicals are added to the production pipe to try to prevent build up of deposits or wax. Remember the oil is warm and so cools on reaching the pipe. In winter or in waxy oils wax formation can plug a pipe and a pig (type of scraper) is sent down to clean the tubes. Even with good management we cannot produce large quantities of crude oil without drilling lots of wells. In PA there are about 100,000 wells that have been drilled for oil and natural gas (many now abandoned). Having said that there are locations in the world where a single well can produce 10,000s of barrels a day.

However, the quantity of crude oil coming out of the ground is a small percentage of what is in the reservoir. If we can increase our extraction efficiency resources that become reserves, our useful supply of crude oil will last longer. I like (industry) video (5 min long) for natural gas (oil extraction is very similar). Pay attention to the drilling and fracking (this is an example of a horizontal well) process. Look for good terminology to use in your exam answers!

Primary Production

The "natural lift" and "artificial lift" might produce 10 - 25% of the oil in the reservoir. To get any more, other techniques need to be used. Of course, these other methods include additional expenses. Many of the Middle East wells have natural lift that runs for very long periods. In the US most of our oil requires artificial lift techniques.

Secondary Production

The saltwater produced by the well or other water (such as municipal drinking water) can be pumped down into the reservoir. The oil, being less dense than the water, floats on top and is thus forced into the well bore of the production pipe. By utilizing water flooding, perhaps an additional 10% can be obtained.

Tertiary Production

Steam or chemicals are pumped down to lower the viscosity of the crude oil and to enhance the extraction process. Of particular interest for Lesson 12 is the use of CO2 as an enhanced oil production technique.

Oil is found in many locations around the world although the high-quality crudes are not as well dispersed. The Middle East now produces almost 30% of the World's crude oil supply.

Map of world's oil production by region (29% Middle East, 20% North America, 12% Eastern Europe, 11% Far East and Oceania, 10% Africa, 9% Central and South America, and 9% Western Europe).
Leading nations for oil production.
Credit: EIA
 Graph of Middle East production, Saudi Arabia is the largest.
The Middle East supplies over 1/4 of the world supply. The major producer in the region is, of course, Saudi Arabia. The production costs from the Middle East are a few dollars per barrel. Transportation adds to the cost as do taxes but the profit is still higher than the domestic crude. Purchasing that might have lower transportation costs but higher production costs.
Credit: EIA

Unfortunately, the US production of crude oil is starting to be reduced and this has implications. Click on the image to see why! We are becoming (again) increasingly dependent on imported crude oil. We are starting to look and drill for crude oil in deep water and environmentally sensitive areas. Domestic production is preferred over imports only when the costs are comparable. We take cheaper crude when we can get it. Wouldn't you?

But we also need to realize that the extraction part can go wrong and cause lots of environmental damage. Take a look at these BBC pictures of the Nigeria delta. Some of the oil companies have pulled out because of safety issues, and the locals stealing oil also produces some of the problems. However, it is an environmental disaster that needs to be cleaned up. Social issues are also very important here.

Extraction of the Natural Gas From Shale Gas

Chesapeake energy has a very good 6 min video that gives a good overview of natural gas drilling [6] into shale (similar to oil drilling). Also look at the horizontal drilling and hydraulic fracturing below and "fracking" or the use of water under high pressure to fracture and stimulate the well. You don't need to know all the technical terms, just get the basics of how drilling, stimulation, and extraction occurs. These gas shales are an "unconventional resource" but provide over 10% of our natural gas production. The shale contains organic material (kerogen) that undergoes maturation and the formation of methane. Challenges here are access to large amounts of water for hydrofracking (fracking) and water cleanup (due to chemical additives and hydrocarbon contamination) while protecting the environment. Have the goal of being able to describe the process of drilling (including horizontal drilling) and fracking. Please note that this is for shale gas but also applicable for oil extraction.

Oil Sands and Oil Shale

We have three fossil fuel resources that can replace crude oil. They are oil sands (also formally known as tar sands), oil shale, and coal liquefaction or gasification. These are also known as non-conventional sources.

Oil Sands

Oil sands are important because they are abundant, and Canada has large reserves that they are upgrading to form a "synthetic" crude oil. The major importer of this fuel is the US. By now, you should realize that the stages in the formation of crude oil are as follows:

Organic   → Kerogen  → Bitumen  → Crude Oil & Natural Gas

So we will see that this is similar to the formation of oil shale. The bitumen is a viscous semisolid. It is so viscous (and often solid in cold weather) that traditional oil extraction techniques will not work. Thus, the overburden is removed, and the tar sand extracted in a similar manner to the extraction of coal from a surface mine (although I don't think they need to use explosives to break up the sand in the summer).

The origin of the oil is a controversial subject among geologists, but the predominant theory is that it evolved in highly organic Cretaceous shales in the southern portion of the Alberta Sedimentary Basin. Underground pressure forced the oil to soak into the existing silt grade sediments and localized sand bodies of the McMurray formation.

Syncrude, Canada

The bitumen forms a solid in cold weather, so the tar sands are a rock, but in summer the consistency is that of thick mud. The tar sands are either trucked to the processing plant or sent to a slurry plant, then to the processing plant via a pipeline (why?). Chemicals and heat (retorting) are used to separate the sand grains from the bitumen. The sand then goes back to reclaim the land (fills in the massive holes!), and the bitumen is refined using similar technology to that already discussed for crude oil.

The oil we're talking about extracting here is considered "heavy" oil, a term popular with the masses, but not necessarily accurate, since it refers to the oil's high density. This is in contrast to "light" oil, which is higher quality oil, and which is of lower density, yielding gasoline products more efficiently. The process of upgrading all the "heavy" oil (low H/C ratio) from the oil sands requires lots of hydrogen (usually obtained from methane and from the cooking process). The synthetic crude oil produced is sent via pipeline to refineries in Canada and the US. You might be using gasoline or products from oil sands as our closest refinery in Warren, PA uses this synthetic crude oil along with PA crude oil. The synthetic crude is rich in asphalt and so when you drive new roadways or have a new roof (asphalt shingles) you again might be using oil sand material.

This link helps explain the extraction process a bit more [7] (surface mining and some in situ extraction: drilling, steam, pumping). Goals here are to understand how surface mining and extraction of the bitumen occurs. 

Three trucks hauling their soil sand cargos to be processed.
Trucks hauling their oil sand cargos to be processed.
Credit: Syncrude

Canadian oil sands deposit is the world's largest. To give you some idea of how large their reserve is:

  • It can supply Canada's energy needs for 475 years.
  • It can supply the world's energy needs for 15 years.
  • The reserve is 5 times the Saudi Arabia crude oil reserve.

The Canadian companies extracting the bitumen can make a profit with current oil process this is economically feasible and profitable. It is also a reasonably secure energy source given that now the US and Canada are trading partners, and are friendly [8]. Text Version (click to reveal)

Dr. Mathews: Question, where is the capital of Canada? Well, it is not Toronto, it's not Montreal, and it certainly isn't Quebec. Of course, it is Ottawa. But it is a very strange choice to have the capital sort of far away from everything. And there is a good reason for that. Relationships between the United States and Canada have not always been friendly. Remember that you are a rebellious nation, you gave up the good guidance of the king and the queen, in favor of this democracy crap. And of course when you did the Canadians remained loyal. And so there was definitely a fear of an American invasion into Canada. And I forget what the statistic is, so please do not quote me on this, but it is something like, eighty percent of the Canadian populous lives within one-hundred miles of the Canadian border. You certainly couldn't pick Toronto because of the fear that it would be very easily captured. And you certainly do not want to have your capital city captured. And so the queen, in all of her wise ways, decided that she was going to place the capital of Canada in Ottawa just to be further away. And of course you wouldn't want to put it in Quebec because of the French influence. And that is where it stands. And you can go and see that is has a very similar parliament to the British system and by law, the two benches need to be at least two sword distances apart, also that is an interesting thing. But you haven't always been friendly with the Canadians.

Oil Shale

We also can find carbonaceous rocks that contain significant organic material in the form of Kerogen (with perhaps some bitumen). The prevailing thought regarding the formation of this material is algal blooms in lakes. There is a summer (thick) layer and a thinner winter layer that dies and settles on the bottom of the lake. This created an organic-rich sediment that eventually formed a source rock. The many layers of source rock that are formed indicated that this process might have been occurring for a few million years. Thus, there is a lot of organic material in oil shales. Unfortunately, the long time periods required for crude oil formation and high temperatures have not been obtained and so we have a source rock with very immature crude oil precursor. We can mine the oil shale, crush, and retort (heat with steam) to extract the kerogen. This can then be upgraded or gasified to supply electricity. We have large quantities of oil shale in the US (large areas of the oil shale containing land, are owned by the US Navy (why?). Worldwide the 5 to 6 times the world resource of petroleum. But have you ever heard of it? Currently, it is still cheaper to purchase crude oil than to produce oil from the treatment of oil shale kerogen. The locations in the US are out West mostly within the Green River formation of Utah/Wyoming.

Gasification of Coal

Recall that when South Africa was embargoed because of the Apartheid policy, they had to find an alternative to crude oil. They used coal to supply all of their chemical needs from gasoline, to fertilizer, and explosives. Similar approaches have been used in World War II in Germany (the birthplace of gasification technology), Britain, and Japan. So with gasification of coal, we can produce transport fuels, chemicals, and electricity.

Natural Gas Alternatives

Moon light oil rig in the ocean.
There is great expense in building oil rigs out in the ocean. The structures are massive, it is very expensive and difficult to build, and costly to operate. However, it can extract large quantities of crude oil and natural gas from deep beneath the ocean floor.

Natural gas can be a valuable fuel. However, we have seen that we do not historically have a very large supply of natural gas, or do we? The reserve and resource discussion has relevance here. As we start to run out of supply (we need more than we can produce) the price increases (laws of supply and demand). As the price increases, then those resources that had marginal economic potential now have a greater potential to produce a profit and so are moved from being a resource into being a reserve. Technology also has a role to play: we can drill deeper (in our efforts to find natural gas), or go offshore. We can also look for alternative sources of methane: shale gas, coalbed methane, gas hydrates, synthesis gas generated methane, and landfill gases (methane).

Coalbed Methane

The methane that was once the enemy of the coal miner can now be extracted either prior to mining, or from coal resources that are too deep to be economically mined. Currently, about 7% of the methane used in the U.S. is from coalbed methane. Recall that as the coal matures it is increasingly rich in carbon and towards the end of the bituminous stage there is a loss of hydrogen. Most of this hydrogen forms methane that may become trapped in the porous structure of the coal. Usually after mining coal, the methane escapes or the methane is released along with the ventilation air. We can recover probably about 100 Tcf (trillion cubic feet) or about a 5-year supply if it was to provide all the US consumption.

Plot of the rise and decline of Coalbed methane production in the US, peaking about 2009.
U.S. coalbed methane production.
Credit: EIA

We have always had methane contained within certain coal seams. But not until methane had an increased value was it economically efficient to extract. We also needed to develop the techniques to drill into the coal seams to maximize the return of the methane. With both of these prerequisites in place (high methane cost and advanced extraction technologies), the reserve of coalbed methane has grown despite the methane being extracted (more recent dip is due to the higher value of wet shale gas (wet here meaning containing liquid hydrocarbons also).

Coal Gasification

Synthesis gas (also known as syn gas): CO and H2 is produced by the gasification reaction:

C + H20 ------> CO + H2

The carbon is generic (could be natural gas, coal, char, or any source of carbon in a carbonaceous material). Mostly, however, it will be coal, a fossil fuel that we have a lot of! Steam (or oxygen) is passed over the hot coal and gaseous products form, known as "water gas." The process is endothermic (requires heat) so energy is required to heat the coal, this could be done by coal combustion but this uses a portion of the carbon. Instead, a balance is achieved between the exothermic (heat producing) reaction of carbon and sub-stoichiometric quantity of oxygen (not enough oxygen to produce CO2):

2C + O2 -------> 2CO

and the endothermic reaction gasification reaction.

If air is used the gas has a low calorific value (100-125 Btu/scf) (SCF is standard cubic foot) and can be used as a fuel. Do you remember that nitrogen in the air dilutes the energy of combustion? If oxygen, instead of air, is used to gasify the carbonaceous material, the gas has a medium calorific value (approximately 300 Btu/scf). Or by not adding nitrogen as a dilutant we get more energy out of the synthesis gas.

The water gas is subjected to the water-gas shift reaction:

CO + H2O <-----> CO2 + H2

Which converts some of the CO to CO2 and hydrogen or vice versa. This is done to change the ratio of CO and H2, and through removal or addition of components, changes in pressure and temperature, the equilibrium can be manipulated and the ratio of water-gas components shifted to the desired ratio depending on the required products, which include substitute natural gas (SNG -methane), methanol, or gasoline.

If methane is the desired product, the cleaned gases (to avoid poisoning the catalyst) undergo the water–gas shift to change the H2 to CO ratio to 3:1 prior to the methanation step:

3 H2 + CO ----------> CH4 + H2O

and

C + 2 H2 ----> CH4

Methane Hydrates

 blue flame
A burning lump of methane hydrate.
Credit: NETL

Methane hydrates are important for one reason: there is so much methane in the form of methane hydrates that it dwarfs our traditional supply. If we can only reach a small percentage of the methane hydrates we will have a vast energy source. They are found both on land (in some of the permafrost areas) and in the ocean on the seafloor.

The methane flame shown to the right is blue in color because of the CH radicals within the flame. Here a solid, ice-like hydrate is on fire; the hydrate melts, releasing more methane.

 Permafrost in the artic
Methane hydrates in the arctic
Credit: NETL
 map of known locations of methane hydrates
Location of methane hydrates.
Credit: Oak Ridge National Laboratory

As you can see, we will be increasing the use of these non-traditional sources of natural gas, notably shale gas, tight gas, and coalbed methane (but not methane hydrates, yet!). Tight natural gas is methane from low permeability sources.

Methane growth is predicted to be mostly shale gas with coalbed methane only making a slight contribution
Current and future methane sources for US production.
Credit: EIA

From the Ground Up the World of Oil

This is a very long web page (encyclopedia entry) on petroleum from the National Graphic Organization [9], but scan through it. You should recognize the technical terms and know what they mean. If you use terminology correctly in the written portion of the exam, grades will improve.

Lesson 7 Coverage Map

As with previous coverage maps, this page map represents a summary of the lesson, providing you with a way to quickly refresh yourself on the big ideas and connections in this lesson. This is interactive so move your mouse over the text boxes/shapes for more information. After this take the quiz.

Accessible Version (word document) [10]

Deliverable

After looking at this map, please take the L07 quiz.


Source URL: https://www.e-education.psu.edu/egee101/node/526

Links
[1] https://www.e-education.psu.edu/egee101/node/790
[2] https://oceanservice.noaa.gov/facts/phyto.html
[3] http://walrus.wr.usgs.gov/seeps/what.html
[4] https://www.e-education.psu.edu/egee101/sites/www.e-education.psu.edu.egee101/files/oil_overview.pdf
[5] https://www.e-education.psu.edu/egee101/sites/www.e-education.psu.edu.egee101/files/Lesson06/L06_not_worried.mp3
[6] http://www.chk.com/Media/Educational-Library/Animations/Pages/Completion-Animation.aspx
[7] https://www.canadasoilsands.ca/en/what-are-the-oil-sands/recovering-the-oil
[8] https://www.e-education.psu.edu/egee101/sites/www.e-education.psu.edu.egee101/files/Lesson06/L06_Ottowa.mp3
[9] https://www.nationalgeographic.org/encyclopedia/petroleum/
[10] https://www.e-education.psu.edu/egee101/sites/www.e-education.psu.edu.egee101/files/Lesson07/Lesson%207%20Coverage%20Map.docx