A seismology team in a study led by Southern Methodist University found high volumes of wastewater injection combined with brine extraction from natural gas wells was “the most likely” cause of earthquakes near Azle, Tex., during 2013-14. In an area where the seismology team identified two intersecting faults, they developed a 3D model to assess the changing fluid pressure within a rock formation in the affected area. They used the model to estimate stress changes induced in the area by two wastewater injection wells and more than 70 gas wells. “The model shows that a pressure differential develops along one of the faults as a combined result of high fluid injection rates to the west and high water removal rates to the east,” said Matthew Hornbach, SMU associate professor of geophysics. “When we ran the model over a 10-year period through a wide range of parameters, […]