Stanford scientists have developed a new software tool. This will enable energy companies to calculate the possibility of triggering manmade earthquakes from activities associated with oil and gas production.
Oil and gas operations can generate significant quantities of produced water–brackish water that needs to be disposed of through deep injection to protect drinking water.
Energy companies also dispose of water that flows back after hydraulic fracturing in the same way.
This process can increase pore pressure–the pressure of groundwater trapped within the tiny spaces inside rocks in the subsurface.
This, in turn, increases the pressure on nearby faults, causing them to slip and release seismic energy in the form of earthquakes.
Identifying which faults are likely to be problematic, the newly developed Fault Slip Potential (FSP) tool uses three key pieces of information to help determine the probability of a fault being pushed to slip.
The first is how much wastewater injection will increase pore pressure at a site. The second is knowledge of the stresses acting in the earth.
This information is obtained from monitoring earthquakes or already drilled wells in the area. The final piece of information is knowledge of pre-existing faults in the area.
Such information typically comes from data collected by oil and gas companies as they explore for new resources.
Researchers have started testing their FSP tool in Oklahoma, which has experienced a sharp rise in the number of earthquakes since 2009, due largely to wastewater injection operations.
