I have never been very interested in oil. Perhaps this is because its lack of pricing consistency, which I find rather annoying and therefore try to put any thoughts of oil out of my mind. Regardless, oil is directly related to the study of Geology, and therefore it would be beneficial to myself and other students in this class to absorb at least some general knowledge of it. Although Professor Pillar shared with the class a brief overview of how oil is formed and collected, I decided to learn and write a little more about the process. In order to begin my online research of how to drill for oil, I visited the How Stuff Works article, entitled “How Oil Drilling Works,” which can be found at http://www.howstuffworks.com/oil-drilling.htm.
Many Americans are only vaguely aware of the impact of oil on our economy. According to the article mentioned above, “In 2005 alone, the United States produced an estimated 9 million barrels of crude oil per day and imported 13.21 million barrels per day from other countries.” That’s a lot of oil, to say the least. According to http://maps.unomaha.edu/Peterson/funda/Sidebar/OilConsumption.html, the United States uses 19.6 million barrels of oil per day, which accounts for 25% of the world’s daily oil consumption, which means ute US produces 25% of the world’s carbon emissions. Out of those 19.6 million barrels of oil, the United States only produces 5.8 million barrels each day.
Where does this oil come from and how do we obtain it? First of all, consider what “oil” is. The term “oil” actually refers to “the remains of tiny plants and animals (plankton) that died in ancient seas between 10 million and 600 million years ago” (How Stuff Works, “Forming Oil”). These remains collected and settled together, forming layers. These layers formed what is known as “source rock” when they mixed with other sediments that accumulated on the ocean floors. As multiple layers formed, the pressure and heat exerted onto the source rock greatly increased. As we have learned much earlier in class, when rocks are exposed to intense heat and pressure, they usually melt. The source rock then becomes oil and gas. When the oil settles and is absorbed in more porous rocks, such as limestone or sandstone, they become trapped when a caprock, usually granite or marble, covers them and prevents them from escaping.
So we just drill a hole in the caprock and the oil comes out, right? Well, contrary to how it is portrayed in movies and TV shows, locating and drilling for oil is actually a science that requires a lot of forethought and calculated procedures. In order to first locate an oil reserve, geologists can use a variety of tools, including gravity meters, electronic noses, or seismology. Once the oil resivoir is located and the site boundaries are set, the drilling begins. After the rig has been set up, the crew drills what is known as the starter hole. From this, they drill deeper into the earth, and stop at a precalculated depth, precisely where the geologists have estimated the reserve to be located. The crew then sets the casting of the pipes immeadiately after drilling the hole, so the hole does not collapse. Once this task has been completed and the cement has hardened, the rig is removed and replaced with a well and a pump. This contraption uses an electric motor to push a rod up and down, wich sets the pump into motion.