An operational guide to resin 3D printing of geological macromodels

Stereolithography (SLA) is a form of 3D printing that is based on the curing of resin under UV light. There are a wide variety of 3D resin printers on the market that all follow the same general procedure. First, a slicing program is used to slice the model in a sequence of thin layers. The model will be printed in this sequence of layers after it is exported in a format recognizable by a 3D printer. In addition to this main function, slicing programs offer additional features to manipulate the model, adjust print settings, and add model supports. Next, after the printer is set up, the sliced model is loaded onto the printer and fabricated. Once the print is complete, the model can be washed, cured and sanded/polished to the desired finish. In this work, we utilize SLA 3D printing to print geological macromodels, to be utilized in flooding experiments. Images captured from the flooding experiments were then incorporated in a set of visual learning exercises for undergraduate students to enhance the study of immiscible fluid flow in porous media. SLA printing was selected in this use case as it provides important advantages over other common 3D printing technologies (e.g. Fused Depositional Modelling: FDM), such as high print resolvability of sub-millimeter scale pore geometry and a high degree of transparency within the resultant printed models. Overall, this method was found to: • Provide an engaging learning experience for undergraduate students, as the captured flooding experiment image time series allowed students to directly visualize often obtuse fluid flow processes in porous media. • Be easily reproducible: after completing an initial print the method can be reproduced for many different pore networks, allowing for a wide array of comparative studies and learning exercises to be developed.