Three-Dimensional Additive Manufacturing of Artificial Oil Reservoir Rock Core Plugs for Core Flooding Experimental Tests

Laboratory tests in which a fluid or combination of fluids that are injected into a core rock are designed to determine oil reservoir rock petrophysical properties, understand the mobility of fluid flow in the porous samples, and calibrate porous media fluid flow models. The core material is extracted from the oil reservoir. However, the manufacture of core plugs is challenging because of the complexity of extracting natural rocks from the reservoir and their morphological and atypical heterogeneity. In addition, core flooding tests are essentially destructive, making it impossible to achieve experimental repeatability by using identical cores. The use of 3D printing in digital rock physics has permitted the production and replication of synthetic rock samples with the morphological characteristics of natural rocks for core analysis and core flooding tests. This study proposes the 3D manufacture of artificial core plugs from microcomputed tomography of Berea sandstone. The digital samples were constructed using a digital particle packing approach by systematically manipulating rock textural parameters, such as the grain size and shape, cementation pattern, and sorting grain, making it possible to obtain a core plug that fulfills experimental requirements. Before the 3D printing of the sample, the flow distribution through the porous media structure was numerically simulated using the Lattice Boltzmann method to obtain the core plug samples' permeability and porosity. The core plug was digitally embedded within a core holder to generate a stereolithography file for 3D printing of the core flooding setup, which can be used directly in conventional experiments. The permeabilities of the 3D printed plugs were experimentally determined to permit a direct comparison to the numerical results and evaluate the utility of printed plugs for displacement experiments.