Selecting a seismically safe formations for salt water disposal in Delaware basin

The recent increased level of the observed seismicity in Delaware Basin, USA, raises an urgent question of how we can safely dispose polluted water (salt water disposal - SWD). There are many active injection wells within this basin and water is injected into many separated formations. We applied a waveform similarity technique to data from regional stations to detect weaker events than those reported by USGS during years 2013-2017. We were able to detect 20 times more events than USGS. We have performed spatio-temporal correlation between this extended catalogue and SWD injected volumes for various injection formations and distances of events from injectors. Four formations targeted for SWD correlated with seismicity, injection rates into two of these formations correlates with the seismicity with less than one month delay between the injection and seismicity and two of these formations show significant delay of seismicity behind the injection (4 and 10 months) which may indicate indirect connection between SWD and seismicity.