U.S. Department of Energy oil research programs have underpinned America's petroleum technology leadership for decades. Some of the most important exploration and production technology advances of the past century had their roots in research programs conducted under DOE/NETL or predecessor organizations. A sampling of those advances includes the first: ? Waterflood research (1920s). ? Mud-pulse telemetry paving the way for downhole data gathering (1970s). ? Chemical enhanced oil recovery (1970s). ? Polycrystalline diamond compact (PDC) drillbits now one third of the market (1980s). ? Through-casing resistivity tool, for downhole logging (1990s). ? Cross-well seismic, for subsurface imaging (1990s). ? Three-phase relative permeability measurement (1990s). ? 4-D seismic imaging (2000s). ? Borehole seismic instruments (2000s).