Abstract: Stress rotation due to depletion can be estimated in reservoirs having an impermeable reservoir boundary. More specifically, the isotropic change in stress due to depletion, and the uniaxial stress resulting from a change in pore pressure across an impermeable boundary are both modeled as perturbations to an initial stress state. These perturbations can result in a rotation of the principal stress directions. Estimates of the stress rotation are helpful for hydraulic fracturing operations, because fracture tends to occur in a plane perpendicular to the least principal stress.

Abstract: Stress rotation due to depletion can be estimated in reservoirs having an impermeable reservoir boundary. More specifically, the isotropic change in stress due to depletion, and the uniaxial stress resulting from a change in pore pressure across an impermeable boundary are both modeled as perturbations to an initial stress state. These perturbations can result in a rotation of the principal stress directions. Estimates of the stress rotation are helpful for hydraulic fracturing operations, because fracture tends to occur in a plane perpendicular to the least principal stress.

Abstract: A hydrocarbon-bearing strata in a hydrocarbon producing well is fractured using a fracture pressure which will not propagate the fracture into adjacent overlying and underlying non-producing strata. The least principal compressive stress S.sub.3 of the hydrocarbon bearing strata and the adjacent overlying and underlying strata are determined by the relationship ##EQU1## where S.sub.1 is the maximum principle compressive stress, P.sub.F is the pore fluid pressure, and u is the coefficient of friction. The fracturing pressure is selected to be greater than S.sub.3 for the hydrocarbon bearing strata but less than S.sub.3 for the adjacent overlying and underlying non-producing strata. Hydrocarbon bearing formations suitable for hydraulic fracturing can also be identified.