Nanotechnology-based drilling fluids are a newly patented, largely untested technique for utilizing silica nanoparticles, five to 40 nanometers in diameter, that are virtually the same size as the pores in the shales being drilled. These particles plug up the pores and make them impervious to water thereby reducing water invasion. Water-based drilling fluids may cause the shale to expand and/or contract. This can lead to an unstable wellbore. Usually the work-around for this problem is to use oil-based drilling fluids. However, oil-based drilling fluids may lead to environmental issues. Nanotechnology may ultimately enhance the usefulness of the less environmentally-problematic water-based drilling fluids.
Patents for drilling fluid nanoparticles were developed by Professor Mukul Sharma in the Department of Petroleum and Geosystems Engineering at University of Texas. During the Fall of 2009 these patents were licensed by M-I SWACO--the world's largest supplier of drilling fluids.
As of December, 2009, there were no known examples of using nanotechnology in the Marcellus shale.