Microhole technology development is based on the premise that with advances in electronics and sensors, large conventional-diameter wells are no longer necessary for obtaining subsurface information. Furthermore, microholes offer an environment for improved substance measurement. The combination of deep microholes having diameters of 1-3/8 in. at their terminal depth and 7/8-in. diameter logging tools will comprise a very low cost alternative to currently available technology for deep subsurface characterization and monitoring.