Oil and Gas Exploration

Oil and gas reserves tend to collect in porous sedimentary rocks that are bounded on the top by a non-porous or impermeable layer of rock that forms an upside down pocket. Folds or disruptions in the layers of rock - a result of pressure within the earth's crust, earthquakes, and salt formations, to mention a few - can all create the geological conditions, or pockets, to capture oil and gas. Hills can sometimes be a reflection of this rock landscape below the earth's surface.

Before the sophisticated technology of today, oil and gas exploration depended on the ability of surveyors to conduct geological surveys and make educated guesses based on the shape and composition of the landscape. This approach was fairly effective, but did have some limitations that resulted in many dry wells. Numerous new technologies and approaches have greatly improved the success of exploration by allowing surveyors to see what is happening deep below the earth's surface, including the probable location of petroleum reserves. For example geoseismic surveying, which involves sending sound waves into the ground, has become a valuable tool in oil and gas exploration. Accuracy in knowing where reserves are located is vital because drilling a well can cost millions of dollars.