Two-dimensional models were used to analyze the behavior of hydraulically pressurized fractures near well bonded interfaces that are located between two materials. Specifically, ways of how existing small fractures interact with a pressurized fracture were analyzed, including some effects of branching and blunting of the pressurized fracture. The strain field along on interface caused by a pressurized fracture near that interface is also discussed. Analysis of the well-test data from the Mobile Piceance Creek Unit Well F31-136 was continued to analyze the effects of a finite conductivity fracture. Results of this analysis show that it is impossible to uniquely determine whether the pressure buildup characteristics are controlled by skin-damage ''scum''or by finite conductivity in the crack. In addition, polyaxial experiments to determine the effects of principal stress magnitudes in Dresser Basalt confirm that fracture geometry is strongly controlled by principal stress magnitude. 22 figures, 2 tables.