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Rock Physics Driven Workflow for Pressure and Saturation Control in Quantitative CO2 Monitoring
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
The injection of CO2 into the subsurface requires a detailed understanding of the petrophysical properties and rock physical frame of the formation under stress. We present the results of a rock physics driven workflow to analyse and steer a planned acquisition campaign at the field laboratory of Svelvik, Norway. The underlying assumptions made for the unconsolidated high porosity formation have a significant impact on the expected seismic response. For a shallow aquifer pressure and saturation dependent P- and S-wave velocities are computed. The rock physics model is based on a solid frame consisting of quartz and clay and saturated with water and gas. For increasing pressures and saturations the expected seismic response is used to discriminate pore fluid and pressure effects. Using a finite differencing scheme the wavefield is modelled and amplitude variations analysed for a geometrically growing CO2 plume over time. The results of the forward modelling will aid in the re-evaluation and subsequent integration of monitoring data for enhanced site conformance assessments, and allow to rapidly re-evaluate possible assumptions made as acquired time-lapsed data reveal mismatches. The integrated workflow coupled with dynamic simulations will provide a possibility to define and evaluate conformance measures during operation.