Finding Oil and Gas — and More

Chip-scale atomic clocks were developed with funding from the military and a military use in mind: enabling soldiers to navigate securely in conflict zones without relying on GPS. But another very different application for these clocks has emerged. Since hitting the market, they have primarily been used to provide precise timing for underwater sensors used in seismic research, often related to gas and oil exploration.

Here’s how this works: Prospectors for oil and gas deploy networks of seismic sensors on the ocean floor, then set off pulses of sound waves that travel through and reflect off underground rock layers. Sound travels at different speeds through oil, gas, rocks and sediment, so precisely measuring how long it takes for sound waves to reach the sensors can indicate the presence of oil or gas.

Like all waves, sound waves carry information in two ways: their wavelength (the distance between successive wave peaks) and their phase, or where in its cycle the wave is detected. To capture phase information accurately, seismic sensors in a network must be precisely synchronized with each other. On land this can be done using GPS, which uses atomic clocks to provide a common reference time.

But GPS signals cannot reach underwater oil fields. That’s where chip-scale atomic clocks come in. They can run for weeks at a time without needing to be corrected or recharged. Using atomic clock-enabled sensors, energy and mining companies create 3D maps of underground geological structures and features.

This is likely to be just the beginning of atomic clocks’ contributions to subterranean exploration. Einstein’s theory of relativity tells us that clocks are sensitive to the force of gravity, ticking slightly more slowly when close to massive objects. By taking advantage of this deep connection between time and gravity, hyper-accurate atomic clocks could be used to detect underground mineral deposits, water movement, lava flows and more. Such capabilities could also help produce maps showing where water will go in the event of a flood, which in turn could help civil engineers, emergency planners and others tasked with designing infrastructure and keeping people safe.

Today’s field-deployable atomic clocks are not quite sensitive enough for these tasks. But the next generation could be, potentially delivering profound change to fields such as geodesy and mineral exploration.

Learn more about the fascinating relationship between atomic clocks and gravity.

Back to Atomic Clocks: A Technology Powerhouse