Microseismic evaluation

From Wikimarcellus

On board a microseismic logging truck in Greene Co., PA
Photo courtesy of Energy Corp. of America

Microseismic evaluation consists of logging and analyzing the small seismic waves that are produced by hydro-fracturing a gas well. It one way to measure orientation and approximate size of a hydro-fracture. Among other things an operator would study the treating pressure profile as well as the extent of the fracture.

Waves are monitored by configuring an array of geophones in an adjacent well. The location of small seismic events that occur during the fracture are mapped. The approximate spacial geometry of the fracture can then be inferred from these seismic events. Arrays of tiltmeters, either positioned on surface or down a welbore, can also be used to study the progress of a fracture.