Silane Treatment of 3D-Printed Sandstone Models for Improved Spontaneous Imbibition of Water

Due to the natural heterogeneity of hydrocarbon reservoirs, accurate modeling and simulation of geomaterials can lead to sophisticated problems when multiple variables are either unknown or assumed. Additive manufacturing or 3D printing has been shown to alleviate some of the deviation of simulation verification by providing a controlled, repeatable and efficient method to fabricate model sandstone at an unprecedented level. However, the printing process to create 3D-printed model sandstone utilizes a polymer binder that is unlike the cementing material in natural sandstone. For natural materials, years of sedimentation and mineral deposits create crystalline bonds, cementing particulates together. Yet, in 3D-printed sandstone the polymer binding sand grains together are different in both mechanical and hydraulic properties from the surrounding grains. Therefore, there are discrepancies between the hydraulic properties of natural and 3D-printed sandstone that must be investigated to aid simulation and flow studies. One area of discrepancy is the wetting behavior of 3D-printed model sandstone, which has been shown to exhibit a neutral or mixed wettability between oil and water during spontaneous imbibition tests. However, a hydrophilic porous media is required for water-driven recovery simulations, where water can wet the porous media completely and enhance hydrocarbon recovery. By utilizing silane solutions, the contact angle of water on the polymer binder and silica sand surface can be decreased, producing a hydrophilic surface. Through the silane treatment process, it is shown that the spontaneous imbibition of 3D-printed sandstone with water can be dramatically increased (~ 200-fold increase), providing an additional tool for reservoir simulations and suggesting wettability tuning to represent a homogenous porous media.