GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 280-3
Presentation Time: 2:05 PM


BROWN, Megan R.M.1, BARBA, Magali2, GE, Shemin1 and TIAMPO, Kristy2, (1)Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80309, (2)University of Colorado Boulder, Cooperative Institute for Research in Environmental Sciences (CIRES), 216 UCB, Boulder, CO 80309; Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80309

Injection induced seismicity is directly tied with wastewater injection where millions of barrels of wastewater are disposed deep underground each year. Surface deformation near areas of injection has been detected using interferometric synthetic aperture radar (InSAR) in multiple wastewater disposal areas. Surface deformation data could be used to calibrate pore pressure models and infer estimates of the spatiotemporal extent of increased pore pressure that may induce earthquakes. Injection induced seismicity has occurred in Weld County in northeastern Colorado since 2013 and is correlated with injection of disposal wells in the area. Previous studies estimated pore pressure increase within the range of values known to induce earthquakes.

Here, we use surface deformation results from Sentinnel-1 InSAR data to calibrate the pore pressure model around the disposal wells. InSAR results show surface deformation between 2 – 5 centimeters in the line of sight of the satellite near the highest rate injection well areas between 2015 and 2017. An estimate of surface deformation based on the pore pressure model results is made using a 1D approximation of vertical expansion of the geologic material from changes in pore pressure. We calibrate the hydraulic parameters of the pore pressure model using the surface deformation results. We find that the hydraulic conductivity of the injection interval is within the range of values estimated from constant-head permeameter testing of core samples and re-analysis of step rate injection tests. This work explores integrating remote sensing and hydrogeology to better calibrate pore pressure models in wastewater disposal areas. Our method of estimating vertical deformation from pore pressure model results is a simple tool that can be used in conjunction with InSAR or other remote sensing techniques to calibrate models and provide pore pressure predictions that can help with mitigation decisions.