The program is primarily theoretical modeling and laboratory experimental; however, the application and interpretation of geophysical logging is an essential part of it. In their current state of development, the theoretical hydraulic-fracturing models show that as pore pressure increases, the matrix stress around a fracture becomes more tensile. Laboratory experiments, which use unconfined ... [Show full abstract] specimens, show that both the characteristics of a layer and the mechanical properties of the adjacent materials control fracturing in the region of the layer. Some long-sweep acoustic-velocity logs were acquired and interpreted. Preliminary analysis of these logs indicates gas-producing fractures intersecting the wellbore. The logs also indicate that other fractures either are nonproductive or do not intersect the wellbore. Mechanical measurements of the Devonian shale indicate fairly uniform mechanical characteristics; however, a degree of mechanical anisotropy was noted for sections oriented horizontally or vertically with respect to the shale structure. Reservoir analyses of the Rio Blanco nuclear stimulation experiment and the nearby massive hydraulic fracturing (MHF) experiment indicate that characteristic lens dimensions were 40 to 60 ft (12 to 18 m) vertically and 400 to 600 ft (120 to 180 m) horizontally. 23 figures.