Center for Subsurface Modeling and Characterizations (CSMC), directed by Dr. Ji Chen, was established as the Well Logging Lab in 1979 by Dr. Liang C. Shen in the Department of Electrical Engineering of the University of Houston to investigate the electric properties of reservoir rocks over a wide range of frequencies. In addition, theoretical and experimental studies have been carried out to obtain a better understanding of electric tool response in complex borehole environments, such as dipping formations, thin invaded beds, and anisotropic formations. All of these studies have the primary objective of improving interpretation of logs obtained with existing tools. Information is also being generated on the design of possible new tools, on the limitations of existing tools, and logging response in complex borehole environments. The research program is supported by a consortium of oil and service companies. The WLL operates the API Nuclear Logging Calibration Facility and has constructed, under a joint API-Industry funding arrangement, a set of Potassium - Uranium - Thorium standard pits. These pits are located on the campus of the University of Houston.