Two-phase flow in porous media and fractures

This dissertation is concerned with numerical and experimental studies of multiphase flows in porous media and fractures.; For the porous media studies a new flowcell was designed and fabricated using stereolithography. This porous flowcell has a lower porosity and wider range of throat capillary and conductance resistances, as compared to previously studied flowcells. Experimental drainage studies of constant-rate air injection into the water-saturated flowcell showed an increase in the percent saturation of the air at low injection rates. This process of low velocity drainage is characterized by small bursts of fluid motion, occurring at seemingly random spatial and temporal locations. Using newly developed image processing procedures and in-house codes, the distribution of these fluid bursts was analyzed and shown to have favorable agreement to the proposed physical theory of self-organized criticality.; A two-dimensional computational model of the fabricated flowcell was meshed with GAMBIT(TM) and two-phase, Volume of Fluid (VOF) simulations were performed with this model using FLUENT(TM) code. Good agreement of the model predictions with the experimental data for the flowcell was obtained for the drainage case of air invading water. The fluid-fluid-solid computational model conditions were then altered to represent the situations of drainage in a glass flowcell and imbibition, the case of the invading fluid preferentially wetting the surface. As the contact angle was varied from the highly non-wetting air-glass condition to the case of imbibition the percent saturation of the invading fluid increased.; For the studies of flow in fractures, binary data from Computerized Axial Tomography scans of a fracture in Berea Sandstone was obtained from Penn State University. This raw data was converted to three-dimensional CAD model. Numerical VOF modeling was performed on a section of this model. The minimum throat area and non-uniform cross-sectional area of the fracture have been shown to affect the distribution of an immiscible fluid invading the fracture. An experimental stereolithography model was also fabricated. Experimental studies of drainage in this fracture model have shown temporal variation in the percent saturation of fluids within the fracture at both high and low constant injection rates. Recommendations concerning future works are also presented.