Background

One of the tools geoscientists use in order to find crude oil and natural gas beneath the surface is seismic technology. Other tools include underground mapping and cores sampling. “Topographic maps” of formations underground, such as isopach maps and structure maps, can help geologists find the formations that may be reservoirs for crude oil. These maps, constructed using well log data, show the thickness of sediments below the surface and can be useful in crude oil and natural gas well placement.

Many types of well logs exist measuring radioactivity, permeability, electrical conductivity, porosity, or some combination of factors. Advances in technology have made geologists’ efforts to find crude oil and natural gas more precise and effective.

Seismic imaging is a tool that bounces sound waves off underground rock structures to reveal possible crude oil and natural gas–bearing rock formations. Seismologists use ultra-sensitive devices called geophones to record the sound waves as they echo within the earth. By studying the echoes, petroleum geologists seek to calculate the depth and structures of rock formations.

Sophisticated 3D imaging creates high-definition pictures similar to an X-ray scan or medical sonogram, that covers several square miles and extends miles into the earth. Geophysicists analyze these images and predict whether the structures revealed are conducive to containing reservoirs of crude oil and natural gas. The only way to confirm the prediction is by actually drilling wells.

Recording multiple 3D surveys at different times produces 4D information. The images show a reservoir at different stages of depletion, allowing petroleum engineers to improve recovery and produce the resource more efficiently and effectively.

Activities

  1. 3.1 Sound boards
    How can sound tell you what’s undergound?
  2. 3.2 Skewer contour mapping
    How can you map what you cannot see?

Assessment

  1. 3.3 Seismic assessment
    How does the industry use sound waves?

Digital extras