FAST, CHEAP, AND REPEATABLE TWO-PHASE FLOW EXPERIMENTS USING 3D PRINTED MICROFLUIDIC DEVICES

Understanding of the various mechanisms occurring during multiphase subsurface processes such as CO₂ dissolution and snap-off events is vital to optimise large scale processes such as CO₂ sequestration, improved oil recovery and energy storage. Recent advances in three-dimensional (3D) printing allows for cheap and fast manufacturing of complex porosity models, allowing investigation of specific flow processes in repeatable manner and enabling sensitivity analysis for small geometry alterations. Yet there are concerns regarding dimensional fidelity, shape conformity and surface quality, and therefore the printing quality and printers’ limitations must be benchmarked. Direct Numerical Simulations (DNS) allows for numerical investigation of interfacial mass transfer during CO₂ dissolution processes. Yet there is lack of experimental work that can validate the existing models.

We present an experimental investigation into the ability of 3D printing to generate custom-designed micromodels accurately and repeatably down to a minimum pore throat size of 140 μm, which is representative of the pore-throats seen in coarse sandstones. Particle Image Velocimetry is used to compare the velocity map obtained from one-phase flow experiments in 3D printed micromodels with the map generated with direct numerical simulation (OpenFOAM software) and an accurate match is obtained. Furthermore, we use the 3D printed micromodel to investigate the dissolution of a trapped CO₂ gas bubble in a single pore to observe the impact of the pore geometry on the dissolution rate of the bubble. This experimental work can be used to validate Direct Numerical Simulation models. Our investigation suggests that 3D printed micromodels can be used for fast and cheap prototyping of flow experiments, and to investigate the physics of two-phase systems, including the occurrence of snap-off events, the impact of viscosity ratio, and the effect of gas solubility in water.