Technical support for geopressured-geothermal well activities in Louisiana; Final report, 1 January 1992--31 December 1993

The US Department of Energy has operated continuous-recording, microearthquake monitoring networks at geopressured-geothermal test well sites since 1980. These microseismic networks were designed to detect microearthquakes indicative of fault activation and/or subsidence that can potentially result from the deep subsurface withdrawal and underground disposal of large volumes of brine during well testing. Seismic networks were established before the beginning of testing to obtain background levels of seismicity. Monitoring continued during testing and for some time after cessation of flow testing to assess any delayed microseismicity caused by the time dependence of stress migration within the earth. No flow testing has been done at the Hulin well since January 1990, and the Pleasant Bayou well has been shut down since September 1992. Microseismic monitoring continued at the Hulin and Pleasant Bayou sites until 31 December 1992, at which time both operations were shut down and field sites dismantled. During 1992, the networks recorded seismic signals from earthquakes, sonic booms, geophysical blasting, thunderstorms, etc. However, as in previous years, no local microseismic activity attributable to geopressured-geothermal well testing was recorded