In the 1990s, gasoline prices seldom exceeded $1.25. Today, most of us agree that gas for less than $3.25 is a bargain (check out how gasoline prices have fluctuated over the last 20 years). Increasing fuel prices is a trend that is likely to continue as oil, the principal ingredient of gasoline, becomes increasingly rare and expensive to extract from below the Earth’s surface. Though electric engines are gaining in popularity, our dependency on oil and gasoline is likely to continue for the foreseeable future. Petroleum engineers, geologists, and a slew of other scientific fields have a “patch” to our oil needs for the time being, but it is not without controversy. Hydraulic fracturing (also called fracking) is a novel method of extracting petroleum from fields where traditional drilling techniques would produce too little to justify their cost. To understand how fracking works we first need to understand a little about the nature of oil.
Many of us have an image of a vast underground cave filled with dark, shimmery oil, lying hundreds or thousands of feet below our feet. Finding these oil reserves is less of a guessing game and more a hard science to locate oil caches. Geologists use a variety of methods to locate oil deposits such as extremely sensitive magnetometers, sniffers, and, more commonly, the science of seismology. When we drill for oil, we basically insert a long straw into the ground that “drinks up” the oil and pumps it back up to the surface. Unfortunately, a lot of underground and undersea oil deposits are not huge subsurface pools; instead, the oil is trapped in the pores of rock (often shale) much like how a sponge holds water. Drilling into the shale layers does little to release the oil trapped within the rock, but fracking has the ability to metaphorically “squeeze out the sponge” and release the shale-trapped oil.