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Project Summary

Difficulty	3  –  5
Time required	Average (about one week)
Prerequisites	None
Material Availability	Sedimentary rocks must be purchased from a science supply store.
Cost	Low ($20 - $50)
Safety	No issues

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Objective

To determine what types of sedimentary rock make the best storage rocks for petroleum oil.

Introduction

Stop, look down, and wiggle your toes. Are you wearing shoes? If you are, chances are good that some part of those shoes is made from petroleum oil. Now look at the fabric of your clothes, your chair cushion, your bedspread, mattress, carpet, and drapes. Many of these fabrics were made from oil. Wander into the kitchen for a glass of milk or soda. The wax in that milk carton and materials in the soda bottle were made from oil. Open up the fridge and look at all the fruits and vegetables—those were grown with the help of fertilizers and pesticides, which are also oil-containing products. Check out your cupboards. All the packaging you see is made from oil, and the canned goods have additives made from oil, too.

Next, head to the bathroom and take a look at all the makeup, medicines, lotions, toothpaste, shampoos, and bandages made from oil. The laundry room also has oil-derived detergents to keep all those oil-made fabrics clean. And even the roof that keeps you dry needs oil to make it waterproof. Oil products are outdoors, too—in car tires, roads, and in the fuel that powers cars and ships, and heats homes. Seems like everywhere you look around your home, from the ink in your pen to the CD's in your player, you see something that was made from oil.

Where do petroleum geologists and petroleum engineers find the petroleum oil to meet all these human needs? As shown in Figure 1 below, they find it inside the earth, where it was made from the remains of tiny sea animals and plants, called plankton, that died millions of years ago, and settled to the floor of ancient seas. Over many years, layer after layer of sediment covered up the decaying plankton, and, when combined with heat and pressure, slowly turned into petroleum oil. After the oil was formed in source rock, it slowly moved upward until it reached the surface, or became trapped in storage rock.

Figure 1. This figure shows good places under the earth to try and find petroleum oil and natural gas.

The first known oil wells to tap into this storage rock reached a depth of about 800 feet. They were drilled in China around 347 CE (Common Era) using drill bits (cutting tools) attached to bamboo sticks. The people used the oil recovered from these wells not to run cars, of course, or even to heat their homes, but to evaporate brine (very salty water) and make salt, which was highly prized. Oil wells today routinely reach depths of 1 mile, and the deepest well ever drilled is in Russia and has a depth of 7.2 miles! In spite of the ability to reach these tremendous depths, oil reserves are limited, and by the end of this century, people will have to find alternatives to petroleum oil for all their food, homes, construction materials, and transportation needs.

The remaining petroleum oil is only found in sedimentary rock, one of the three main types of rocks found on Earth. Common types of sedimentary rock are limestone, chalk, sandstone, and shale. In this geology science fair project, you will test three of these types of sedimentary rock, and see which one soaks up oil the fastest, and which one holds the most oil and makes a good storage rock. This will allow you to discover which kinds of sedimentary rock petroleum engineers explore to find the last oil reserves on Earth.

Terms, Concepts and Questions to Start Background Research

• Petroleum oil
• Petroleum geologist
• Petroleum engineer
• Plankton
• Sediment
• Source rock
• Storage rock
• Sedimentary rock
• Limestone
• Sandstone
• Shale
• Natural gas
• Archimedes' principle
• Density

Questions

• What are some of the ways petroleum oil is used in your home?
• How is petroleum oil formed?
• Where do geologists and petroleum engineers try to find oil?

Bibliography

This source describes the formation and types of sedimentary rock:

• Wikipedia Contributors. (2008, December 18). Sedimentary rock. Wikipedia: The Free Encyclopedia. Retrieved December 18, 2008, from http://en.wikipedia.org/w/index.php?title=Sedimentary_rock&oldid=258842092

This source describes how sedimentary rocks have been used as a building material:

• Aldokkhan. (2008). Building and Ornamental Stones of Egypt. Retrieved December 19, 2008, from http://www.aldokkan.com/art/stone.htm

This source describes how petroleum is formed and how it is used:

• Petroleum. (2008). The Need Project. Retrieved February 6, 2009, from http://www.need.org/needpdf/infobook_activities/ElemInfo/PetroE.pdf

This source shows where to find fossil fuels underground:

• King, C. Where shall we drill for oil? Retrieved February 6, 2009, from http://earthlearningidea.pbwiki.com/f/Sorting_Sequence.pdf

For help creating graphs, try this website:

• National Center for Education Statistics (n.d.). Create a Graph. Retrieved February 6, 2009, from http://nces.ed.gov/nceskids/CreateAGraph/default.aspx

Materials and Equipment

• Sedimentary rock samples, of approximately the same size; available at science supply stores, such as Carolina Biological Supply Company (search for "Sedimentary rock specimens"): www.carolina.com. Carolina Biological sells packs of 10. You will only need 3 samples from each pack.
  1. Limestone (3 samples)
  2. Sandstone (3 samples)
  3. Shale (3 samples)
• Paper plates (9)
• Optional: Magnifying glass
• Eyedropper
• Mineral oil; available at drug stores
• Stopwatch or clock with a second hand
• Lab notebook
• Graph paper

Experimental Procedure

Preparing Your Rock Samples For Testing

1. Place each of the nine rock samples (three of each type) on its own paper plate. Use a pen to label the paper plate with the name of the rock: limestone, sandstone, or shale.
2. Look carefully at the rocks and write down the differences that you can observe in your lab notebook. Look at the rocks using a magnifying glass, if desired. Which rock looks like it might hold more oil?

Testing Your Rock Samples

1. Fill up the eyedropper with mineral oil.
2. Add five drops of oil to the first limestone sample, and then immediately start the stopwatch.
3. Stop the stopwatch when the oil has soaked into the limestone. Record the time in a limestone data table, like the one below, and reset the stopwatch.
4. Continue adding drops of oil to the limestone, one at a time and counting the drops as you add them, until the rock will not hold any more oil and the oil begins to pool around the rock. Record the number of drops that you added in your limestone data table.
5. Repeat steps 1–4 for the other two limestone samples.
6. Repeat steps 1–4 for the three sandstone samples, and record your data in a sandstone data table.
7. Repeat steps 1–4 for the three shale samples, and record your data in a shale data table.

Limestone Data Table

Analyzing Your Data Tables

1. Using the data in your limestone data table, calculate the average time it took for the limestone samples to absorb five drops of mineral oil by adding up the three sample times and dividing by 3. Record your calculation in the limestone data table.
2. Using the data in your limestone data table, calculate the average number of drops of oil that the samples were able to hold and record your calculation in the limestone data table.
3. Repeat steps 1–2 for the sandstone data table.
4. Repeat steps 1–2 for the shale data table.
5. Make a bar chart showing the average time it took for each rock type to absorb five drops of oil. Label the x-axis Type of sedimentary rock, and the y-axis Average time to absorb 5 drops of oil. You can make the bar chart by hand or use a website like Create a Graph to make the graph on the computer and print it.
6. Make a bar chart showing the average number of drops of oil that each type of rock could hold. Label the x-axis Type of sedimentary rock, and the y-axis Average number of drops of oil absorbed. You can make the bar chart by hand or use a website like Create a Graph to make the graph on the computer and print it.
7. Looking at your graphs and data tables, which type of sedimentary rock soaked up the oil the fastest? Which type of sedimentary rock soaked up the most oil? Which rock do you think is the best storage rock?

Variations

• Using Archimedes' principle, and your leftover rock samples that have not yet been tested, determine the density of each type of sedimentary rock, and plot the density on the x-axis and the average number of drops of oil each sample could hold on the y-axis.

• For more science project ideas in this area of science, see Geology Project Ideas.

Credits

Kristin Strong, Science Buddies

This science fair project idea was based on an experimental procedure outlined in the following source:

• Harcourt Science. What Kinds of Rocks Store Petroleum? Harcourt School Publishers, 2000. pp. E10-E11.

Last edit date: 2009-02-16 12:34:00

Career Focus

If you like this project, you might want to think about career opportunities in Geology.

Just as a doctor uses tools and techniques, like x-rays and stethoscopes, to look inside the human body, geoscientists explore deep inside a much bigger patient—planet Earth. Geoscientists seek to better understand our planet, and to discover natural resources, like water, minerals, and petroleum oil, which are used in everything from shoes, fabrics, roads, roofs, and lotions to fertilizers, food packaging, ink, roads, and CD’s. The work of geoscientists affects everyone and everything. Learn more about this career: Geoscientist.