Subsurface faults and present-day stresses in southern Kansas: Implications for brine disposal and long-term storage of CO2
Kansas resides within the midcontinent where strain rates and historical seismicity are low. However, the state has experienced unprecedented seismicity since 2013. The seismicity is temporally and spatially coincident with major brine disposal operations in the southern part of the state, raising concerns about (1) the role of fluids in fault reactivation and (2) how to properly site and manage wells for saltwater disposal and for long-term storage of CO2. A major hurdle for stakeholders in the region is that subsurface faults and stresses are poorly resolved. To address these issues, we use new structure contour maps of major stratigraphic surfaces to map potential faults. The maps are derived from a catalog of >500,000 stratigraphic tops, established from the Kansas Geological Survey's well database, that cover an area of ∼62,000 km2. To identify potential faults, we pair surface analysis methods with evaluation of isopach trends. To validate faults, the mapped features will be compared to faults identified in 3D seismic data; lineaments determined from analysis of potential field data; and surface lineaments mapped from satellite data, LiDAR DEMs, and air photos. To identify faults that have the highest risk for failure, we are mapping in situ stress orientations and magnitudes using well log and test data. The resulting fault and stress maps will provide regional stakeholders a basis for identifying high and low risk injection sites and context for future seismicity.
AAPG Datapages/Search and Discovery Article #90221 © 2015 Mid-Continent Section, Tulsa, Oklahoma, October 4-6, 2015