SEISMIC MONITORING OF CO_2 INJECTION USING A DISTORTED BORN T-MATRIX APPROACH IN ACOUSTIC APPROXIMATION

摘要

Monitoring the injected CO2 distribution is at the core of any carbon capture and storage project. Waveform inversion methods can be used to obtain high-resolution images for monitoring the injected CO2 in the subsurface, but remains computationally challenging. Efficient modelling approximations are desirable for solving time-lapse inversion problems and to test the settings in which they give accurate predictions. We employed the distorted Born approximation (based on scattering integral equation) to simulate time-lapse synthetic data for a CO2 injection scenario with a single injector, and benchmarked it against the finite element and exact T-matrix approach. The distorted Born approximation presented, considers a general heterogeneous reference medium; and provides a framework for imaging of regions of time-lapse variation using the baseline survey as a reference and the monitor survey as perturbed to directly estimate the perturbation.