Changes

In some cases – the Marcellus Shale, for example – the distance between the gas/oil-bearing strata and the deepest fresh water aquifer is more than 5,000 feet. In others, as in the San Joaquin Valley, this distance can be more than 25,000 feet.

In some cases – the Marcellus Shale, for example – the distance between the gas/oil-bearing strata and the deepest fresh water aquifer is more than 5,000 feet. In others, as in the San Joaquin Valley, this distance can be more than 25,000 feet.

The location and magnitude of created fractures typically are monitored using microseismic and tiltmeter technology, geophysical methods that measure very small seismic events and motion caused by breaks in the rock as it is fractured. The sensors used to measure these events, described as the equivalent to jumping one foot in the air and landing, allows operators to have a better understanding of the volume of rock that they are fracturing and where the cracks are forming.

The location and magnitude of created fractures typically are monitored using microseismic and tiltmeter technology, [[geophysical methods]] that measure very small seismic events and motion caused by breaks in the rock as it is fractured. The sensors used to measure these events, described as the equivalent to jumping one foot in the air and landing, allows operators to have a better understanding of the volume of rock that they are fracturing and where the cracks are forming.

These monitoring programs show that the hydraulically formed fractures are located far from aquifers.  

These monitoring programs show that the hydraulically formed fractures are located far from aquifers.