Where is it found?

Oil seeping out of sandstone on a hot summer day near C-470 and US 285.

Wallace Pratt, a noted wildcatter, once remarked that, “Oil is found in the minds of men”. He was referring to the imagination that it takes to visualize the geological conditions that trap oil underneath the ground. Indeed, most oil is found beneath the ground and it takes special tools and creative thinking in order to find the place where it is hiding.

Some oil makes its way to the surface where it forms oil “seeps”. One such place is at the intersection of C-470 and US 285. These seeps can be clues to buried oil fields.

Oil seeps can be found on the bottom of the ocean such as in the Gulf of Mexico, or off the coast of California. Some of the seeps on land were used by early pioneers to grease the axles of their covered wagons as they trekked across the West.

The dark colors in this rock are oil saturated pore spaces within the sandstone

The term “oil pool” is very misleading because beneath the ground the oil is not found in big lakes or pools of oil. Rather, it occurs in the tiny openings between the grains in sandstones and limestones. The number and size of the openings in the rock defines the porosity of the rock, usually expressed in percent. The degree to which the openings are connected determines the permeability of the rock. Together, the porosity and permeability of a rock define how much oil can be stored in it and how quickly it can flow out of the rock into the production well.