Natural gas is, in many ways, a substance of the future. It’s a powerful fuel source that will be a key part of meeting the world’s growing demand for energy. It is also the source of chemical compounds that are key to the creation of plastics and other materials used in daily life.
Yet, despite its many uses, natural gas has a prominent past. Natural gas is a “fossil fuel,” and just like the many fossils found in the Colorado soil, there is a fascinating story behind how it came to be where it is today.
One hundred million years ago, most of what is now Western Colorado lay beneath the sea. What would become North America was divided in half by an oceanic channel that linked a cool Atlantic Ocean with an Arctic Ocean much warmer than it is today. These relatively shallow waters were home to a wide array of tiny marine creatures, similar to plankton.
As Colorado’s ancient shores slowly ebbed and flowed over millions of years before disappearing completely, a rich layer of microscopic organisms became trapped in what was then the sea floor. Some of them had been photosynthetic, using the same chemical processes that plants use to turn the sun’s energy into food. Others were active hunters that went after other plankton, including the ones that fed on sunlight. Ultimately, hunter and prey alike were deposited on the floor like a compost pile full of the sun’s energy and were eventually covered by a layer of silt and mud.
Ancestors to modern coral developed on top of that mud layer. Over the years, their stone-like bodies turned into limestone deposits, which pressed down with increasing pressure on the microorganisms deposited on the original sea floor. More sediment eventually covered the coral, and the process repeated until the tides finally ebbed for good, leaving the region dry.
Millions of years beneath stone and soil put tremendous pressure on the microorganisms, and volcanic activity and seismic shifts squeezed them further. The organisms broke down over time, and the chemicals and energy that they had captured were transformed by the pressure into a thick mix of hydrocarbons that lay miles beneath the surface of the Earth.
Over time, and as they “cooked” amid the Earth’s subsurface depths and pressures, these hydrocarbon deposits separated, with the thicker chemicals and compounds sinking to the bottom to become crude oil, and the thinner and lighter ones rising to the top. Among the lightest of those compounds is methane, the main ingredient in natural gas.
Much of the methane within the Earth is stored in the same rock layers as crude oil and is what we know as natural gas. However, the gas will not stay in one spot if the surrounding rock is particularly porous, or full of small holes. Instead, it will spread throughout the surrounding rock formation.
Energy companies extract both conventional and non-conventional natural gas in Colorado. Conventional natural gas is easier to access and comes up from the ground easily with conventional drilling, though this means of extracting hydrocarbons is increasingly rare. Unconventional gas, on the other hand, requires the use of a mixture made up proportionately of mostly sand and water to create tiny, hairline fractures in the rock that release the gas. The sand in the mixture makes its way into the cracks of the rock, propping them open and making it easier for the trapped gas to flow to the surface.
As it turns out, Colorado’s geological past plays a big part in the state’s economic present—as well as its future. Fossil fuels are extremely valuable and important to our way of life, and harvesting them is an important industry in the Centennial State. Extracting the fossil fuels left behind millions of years ago provides communities across the state with millions of dollars with which to invest in the future, not to mention a cleaner source of affordable fuel to power the future.