Carbon dioxide miscible flooding: A study of enhanced oil recovery in a five layer laboratory model and of fluid mechanical behavior with computed tomography in a one layer laboratory model

Carbon dioxide (CO2) flooding projects have shown a large potential for oil recovery and are extensively used. Previous laboratory studies of CO2 flooding experiments in a scaled one layer reservoir model have shown the promising results that can be achieved. The ultimate goal of the research project is to place a multilayer system in a computed tomography (CT) scanner to view flow in each layer. From these experiments the relative detractions of the fluid mechanical effects of gravity tonguing, viscous fingering, and well pattern areal sweep behavior to the overall oil recovery of the process can be determined.;This work accomplishes two steps toward this goal and focuses on a study of the enhanced oil recovery CO2 miscible process using two scaled laboratory reservoir models. Model 1 consisted of a one layer model, and model 2 was comprised of five layers of different porosity and permeability. A suitable flow system for performing displacement experiments, while the models were placed in a CT scanner, was developed. The goal of this part of the work was to demonstrate the feasibility of using CT scanner experiments to study fluid flow patterns in the case of the CO2 miscible process. The experimental data can provide a bench mark on how well computer simulations can follow a fluid front when instabilities are present. However, in the case of model 2, scanner limitations did not allow us to study the five layer model with glass beads representing the porous medium. This part of the work was therefore carried out outside the scanner. This work gave us important insight into the flow behavior in a layered reservoir. It showed that the foam process is very efficient in providing the overall best oil recovery in both secondary and tertiary floods.