Particle-laden fluids pervade oil/gas drilling and production, such as drilling fluids, fracturing fluids, and fines migration in the reservoir formation. Particle types include nanoparticles, clay minerals, and fines, with particle sizes spanning from nanometer to millimeters. These particles may interact among themselves, with other particles, the porous medium, and the liquid-fluid interface. Research tools adopted for this study include adsorption columns, microfluidics, analytical solutions, and numerical simulations.Surface modified nanoparticles show a strong affinity for the water-oil interface. Particle accumulation at the interface alters the capillary behavior and immiscible fluid displacement. Experimental results identify the inherent asymmetric behavior of the particle-coated interface, and the modified interface can resist a substantial pressure difference. The adsorption of nanoparticles onto mineral surfaces is a major constraint for applications of nanoparticles which require long transport distance, e.g. groundwater remediation and enhanced oil recovery. Adsorption column tests suggest that pH, ion type/concentration, and the mineral composition of the porous medium influence the adsorption and transport of nanoparticles. Migrating particles may plug pore constrictions and reduce permeability when the constriction-to-particle size ratio is small. Transparent microfluidic chips allow the visual observation of pore clogging and its development; image analyses demonstrate that pore constrictions near clogged pores have a higher probability of clogging compared to pores at any random location. A filter cake eventually builds up on the surface of a porous medium when extensive clogging develops as a slurry presses against the medium. A comprehensive new mudcake growth model evaluates the influence of time, pressure and environmental factors on the filtration behavior of drilling muds. Subsequent analyses explore critical drilling and completion issues that include mud shearing and differential pressure sticking.Finally, the rapid development of high-resolution magnetic sensors provides an opportunity to develop innovative magnetic logging tools for the quality control of drilling and completion operations. A new magnetic mud is engineered to serve as a tracer material. A multi-sensor probe conducts 3-D measurements of the magnetic field strength along a cased borehole. An efficient inverse algorithm solves the distribution of magnetic materials around the well with high spatial resolution.
Dr. J. Carlos Santamarina
Dr. J. David Frost, Dr. Susan E. Burns, Dr. Sheng Dai, Dr. Guillermo Goldsztein (MATH)