Macro-scale Tomography

The macro-scale core flooding setup integrated with a medical CT scanner at the COIFPM is a reservoir-conditions, multiphase core-flooding system that includes a nine-cylinder Quizix pumping system, two compensation accumulators, an acoustic three-phase separator, air-operated valves, differential pressure transducers, a Hassler-type core holder, and three mechanical convection ovens.

All the wetted parts of the apparatus are made of Hastelloy and other corrosion resistant materials. The experimental setup is a closed-loop system that allows fluids to be co-injected into the core at elevated temperatures and pressures. In order to maintain back pressure, a dual-cylinder 6000 Quizix pump is utilized instead of the more common dome-loaded back pressure regulator (BPR). This allows for a fixed back pressure even at very high flow rates, leading to a stable equilibrium between the fluid phases which is essential when handling miscible fluids such as CO2 and brine. All the injection and backpressure pumps are located inside a large mechanical convection oven from which fluids are sent to and received from the core holder. The effluent of the core is sent to a large acoustic three-phase separator, located in another oven, close to the back pressure regulation pump. The setup also includes a medical CT scanner tuned for petrophysical applications. The scanner is rotated to the horizontal orientation which allows performance of  experiments through vertically-placed rock samples. A vertical positioning system (VPS) is used to move the core holder vertically from bottom into the gantry. During an experiment with a core sample, the VPS is synchronized with the horizontal table of the scanner. The resolution of the CT-scanner is 256 cubic microns, which enables the calculation of the in-situ saturations of the three phases present in the pore spaces. This method enables researchers at the COIFPM to eliminate some of the uncertainties associated with saturation measurements using the mass balance technique, including the impact of end effects on the total fluid-phase saturations.