Double-difference tomography of microseismic data for monitoring carbon sequestration

Summary: More than 2000 microseismic events have been recorded since early 2008 using a cemented geophone string for monitoring CO2 injection at the Aneth oil field in Utah. The double-difference seismic tomography method has recently been developed for improving earthquake locations and imaging the seismic velocity structure. The method uses both the absolute and differential arrival times to invert the velocity distribution and the source locations simultaneously, leading to an improved precision for microseismic event location. We explore the use of doubledifference tomography for obtaining high-precision locations of microseismic events and improved resolution of velocity structure at the Aneth oil field.