Open-Source Tool Kit Uses 3D Printing for Micromodel Generation
Authors: Carpenter Chris 
Published: June 2019

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 190852, “Open-Source Tool Kit for Micromodel Generation Using 3D Printing,” by Thomas D. Seers and Nayef Alyafei, SPE, Texas A&M University at Qatar, prepared for the 2018 SPE Europec featured at the 80th EAGE Conference and Exhibition, Copenhagen, Denmark, 11–14 June.
The paper has not been peer reviewed. In this paper, the authors present an open-source tool kit for the generation of microfabricated transparent models of porous media (micromodels) from image data sets using optically transparent 3D polymer additive manufacturing (3D printing or sintering). These micromodels serve as research and pedagogical tools that facilitate the direct visualization of drainage and imbibition within quasi-2D porous media, generated from a range of image modalities [e.g., thin section micrographs, µ-computed tomography (µCT) orthoslices, and conventional digital photography].
Introduction
Though recent advances in 3D X-ray imaging, such as X-ray microtomography and µCT, permit volumetric imaging of microcore flood experiments with-in geological samples at the pore scale, experimental observations of dynamic (time-resolved) multiphase flow with-in pore networks still are obtained conventionally using transparent etched or molded synthetic porous media commonly referred to as micromodels. Typically, video footage of fluid imbibition and drainage experiments conducted across these quasi-2D pore networks is used to understand fluid distributions and displacement mechanisms within an equivalent 3D porous media. Contrary to state-of-the-art dynamic µCT coreflood experiments, which require synchrotron beam time to be conducted, micromodel studies can be undertaken routinely within a laboratory-based setting with a relatively simple experimental setup. However, the facilities required to fabricate micromodels typically are highly specialized, with production often outsourced to third-party manufacturers.
In this work, the authors consider the potential of using additive manufacturing (3D printing or sintering) as an alternative to conventional micromodel-fabrication techniques. With the advent of light-transmissible 3D-printable materials, flow experiments conducted with these 3D-printed physical models can be captured using widely available optical imaging techniques (i.e., standalone digital cameras and trinocular microscopes). However, a major obstacle encountered in harnessing 3D-printing technologies for the goal of micromodels fabrication is the paucity in software tools capable of processing and converting raster-based images to mesh-based file formats parsable by commercially available 3D-printing systems.
The paper aims to provide an open-source platform through which 3D-printable mesh-based representations of micromodels can be generated from raster imagery. Using this tool, standard micromodel components are fully integrated into the fabricated model. The availability of such a tool kit could act as an enabler for community research into fluid-transport phenomena in porous media. The authors suggest that 3D-printed pore networks may provide an effective pedagogical tool for teaching multiphase flow, enabling petroleum- and chemical-engineering and geology students to visualize directly often obtuse immiscible-fluid-flow processes within the classroom.
Software-Implementation Description
The tool kit is developed in the popular MATLAB language and is executed by graphical user interface. The generation of 3D-printable micromodels from raster datasets comprises three main stages:
Image processing
Micromodel construction
Mesh post-processing