Numerical Modeling of Time-lapse Seismic Experiments to Monitor Co2 Sequestration in a Layered Basalt Reservoir

  • Murari Khatiwada, William P. Clement
  • Published 2009

Abstract

Instead of allowing carbon dioxide (CO2) generated from the burning of hydrocarbons to escape into the atmosphere, CO2 can be captured and stored. For the long term mitigation of the increasing amount of CO2 emissions, its sequestration in geological formations is promising. As a measure, its short and long term monitoring is equally important for environmental and health safety issues. The seismic method is proposed as a non-invasive monitoring technique for geological sequestration of CO2. Based on the positive results obtained from reservoir monitoring during enhanced oil recovery with CO2 floods, geoscientists plan to inject CO2 in layered basalt. CO2 mineralizes rapidly while it is exposed to mafic rocks. Due to CO2 injection, the physical properties of the reservoirs, such as the elastic moduli and the density change. These changes have effects on the seismic velocities. Although basalt seems to have advantages as a reservoir from the CO2 storage point of view, it poses some considerable challenges in terms of seismic monitoring. Strong multiple scattering from the layering of the basalt and high scattering attenuation complicate surface seismic imaging. To investigate the possibilities and limitations of time-lapse seismic monitoring of CO2 injection in a basalt reservoir, a number of numerical simulations are performed. The Spectral Element Method (SEM) and its modeling package SEM2DPACK is used for synthetic data generation. A base case (unperturbed) model is generated and the seismic velocity is perturbed in the reservoir to generate post-CO2 injection models. Among surface seismic, traditional Vertical Seismic Profiling (VSP), and downhole VSP methods used for monitoring purpose, results obtained from the downhole VSP method show significant differences between the preand post-injection seismic sections. Coda Wave Interferometry (CWI) theory is used to quantify velocity changes observed

Cite this paper

@inproceedings{Khatiwada2009NumericalMO, title={Numerical Modeling of Time-lapse Seismic Experiments to Monitor Co2 Sequestration in a Layered Basalt Reservoir}, author={Murari Khatiwada and William P. Clement}, year={2009} }