Using Micro-positron Emission Tomography to Quantify Single and Multiphase Flow in Heterogeneous Reservoirs

Abstract

Understanding and quantifying the role of reservoir heterogeneity on multiphase flow and the immobilization of CO₂ is essential for predicting and validating models of long-term CCS reservoir performance. In this study a novel imaging technique known as Positron Emission Tomography (PET) is used to image pulse tracer transport through a heterogeneous Berea core first during single phase water injection and then during water-gas coinjection experiments. Methods are described for using this spatially and temporally resolved tracer data to describe sub-core permeability, interstitial velocity, tracer flux, relative permeability, and water saturation. The experimental data is then used to build a multiphase, multicomponent 3D simulation model in order to confirm and validate the experimental results. The simulation results highlight the importance of sub-core heterogeneity on relative permeability and saturation distributions which has important implications for understanding and modeling CO₂ distribution and trapping in heterogeneous storage reservoirs.