Fabrication of 2.5D Rock-Based Micromodels With High Resolution Features

Abstract

Fabrication of 2.5D rock-based micromodels with high resolution features is presented using SU-8 multi-layer lithography and nickel electroforming for nickel molds. Processes associated with SU-8 were carefully optimized by the use of the vacuum contact, the use of UV filter, and controls of UV exposure doses and baking times. The use of SU-8 MicroSpray enabled the easy fabrication of multi-layers of SU-8, while exhibiting some total thickness variations. The thirteen layered SU-8 samples showed reliable patterning results for features at 10 and 25 μm resolutions, and minor pattern distortions of features at the 5 μm resolution. Flycutting method employed in multi-layer lithography of SU-8 yielded accurate total thickness control within ±1.5 μm and excellent pattern formation for all of 5, 10, and 25 μm features. Electroforming of nickel was optimized with electroplating bath composition and electroplating parameters such as current density to realize the high resolution nickel mold. The fabricated nickel molds from flycutting based SU-8 samples revealed the feasibility of manufacturing the minimum features down to 5 μm for thirteen layers without any pattern distortions. The replication-based micromolding method will allow for fabrication of micromodels in a variety of materials such as polymers and ceramics. The high resolution, 2.5D micromodels will be used for investigation of pore-scale fluid transport, which will aid in understanding the complicated fluidic phenomena occurring in the 3D reservoir rock.

Spontaneous and Flow-Driven Interfacial Phase Change: Dynamics of Microemulsion Formation at the Pore Scale

“…Further studies are needed to fully characterize such multiphase flow problems where the timescales involved in phase change and bulk flow are comparable. In addition, using micromodels that represent complex geometries of heterogeneous rocks, such as the multiple-scale pore sizes , and fractures, is highly encouraged.…”

Impacts of Mixed‐Wettability on Brine Drainage and Supercritical CO2 Storage Efficiency in a 2.5‐D Heterogeneous Micromodel

“…The pioneering work from Wan et al (1996) improved the glass micromodel design and fabrication to provide the necessary contrast of depths (thus capillarity) between matrix pores and fracture apertures. In recent years, more 2.5‐D micromodels have been used to better mimic real 3‐D porous media and investigate multiphase flow (Park et al, 2015; Yun et al, 2017; Xu, Bonnecaze, et al, 2017; Xu, Liang, et al, 2017). To our best knowledge, there are few studies on unstable drainage processes in micromodels having 2.5‐D pore geometry heterogeneity, especially for GCS applications, and none that have examined impacts of mixed wetting.…”