The objective is to provide technical assistance to METC's effort to develop a leading program in the evaluation of hydrate samples in porous media at reservoir conditions. An existing computer program has been modified to calculate enthalpies of dissociation, equilibrium pressures, and earth temperature-depth profiles for hydrate formation as a function of gas composition. In this report results of the depth-temperature studies are presented. The effect of gas composition, geothermal gradient, permafrost thickness and pressure gradient on the thickness of a hydrate stability zone in permafrost regions is covered. The effect of ocean bottom temperature, gas composition and ocean depth on a hydrate stability zone beneath the ocean is shown. These variables are considered to be among the more important in determining the potential that a particular region has for containing hydrates and they need to be measured in any geological investigation of a region. 24 references, 11 figures, 1 table.