Time-lapse full-waveform inversion for cross-well monitoring of microbubble injection

Abstract

Seismic monitoring is increasingly important to understand time-varying changes in subsurface physical properties for hydrocarbon production, CO2 geosequestration, and near-surface engineering purposes. Since the resulting changes in elastic parameters and then in recorded seismic waveforms tend to be small, full waveform inversion (FWI) can be a powerful method to accurately estimate time-lapse velocity changes by maximizing the use of waveform information. We apply time-lapse FWI to cross-well survey data acquired with highly repeatable pseudo-random sources to monitor microbubble injection into shallow unconsolidated sediments. We use parallel time-lapse inversion, and successfully detect very small time-lapse velocity changes (<1 %) within a thin layer (< 1m) due to highly repeatable data sets, careful data preprocessing, and well-designed inversion procedures. The velocity changes indicate the potential influence of the fluvial depositional environment on the migration of injected microbubble water. Presentation Date: Wednesday, September 27, 2017 Start Time: 11:00 AM Location: 361F Presentation Type: ORAL