Project Wagon Wheel is a joint study by Lawrence Livermore Laboratory (LLL) and El Paso Natural Gas Company (EPNG) to investigate the technical concept of nuclear stimulation of a natural gas reservoir located near Pinedale, Wyoming. Laboratory stress-strain deformation measurements on core samples taken from EPNG Wagon Wheel hole No. 1 (at a depth between 8000 and 12 000 ft) show that the shear failure envelope for Wagon Wheel sandstone is almost identical to that for Hoggar granite. A calculation for Wagon Wheel sandstone for 1-kt energy at a depth of 300 m duplicated cavity radius, shear fracture radius, stressed region, peak particle velocity, and peak acceleration data measured from the nuclear experiments conducted in the Hoggar granite by the French. The conclusion drawn from this comparison is that the Hoggar granite chimneys and regions of increased permeability provide a reasonable model to assume for Wagon Wheel. A single explosive detonated at a depth of 10 000 ft is predicted to produce a cavity radius of 5.77 W1/3 (m,kt1/3), with shear fractures ex tending out to 2.5 cavity radii followed by a stressed region to 5 cavity radii. The expected chimney will have a radius of 1.2 cavity radii and a height of 2.5 cavity radii above the shot point, resulting in an apical void at the top representing about 50% of the cavity volume. Large increase in permeability is expected only within the region of shear fracture. Chimney height for multiple detonations is expected to be 4 cavity radii based on a rubble porosity of 21%. Explosive spacing for multiple simultaneous detonations varies from a minimum of 5 cavity radii (tangent chimneys) to 7.0 cavity radii based on maximum fracture increase due to shock interaction. Explosive spacing for sequential detonation varied between 7.5 and 12.5 cavity radius based on the similarity between cratering phenomenology (reflecting a shock from the ground surface) and reflecting a shock off the apical void of a previously formed chimney. It is expected that a permeable annular ring will form around the axis between the two explosives to connect the lower chimney with the cavity above.