Much of the industry's experience with fracture stimulation comes from basins with low stress and normal fault regimes. The Cooper Basin has high differential stress. It is in a strike-slip fault regime for shallower reservoir levels and a reverse-fault regime for the deeper reservoirs of a new basin-centered gas play. This difference in stress leads to a difference in fracture-stimulation results. Presented here are data on Cooper tectonic stress, rock strength, pore pressure, natural fractures, and borehole breakouts all of which impact fracture-stimulation treatments. Several unexpected behaviors of Cooper fracture stimulations then are discussed and some mitigation suggested. The reader is assumed to be a geoscientist with an interest in this topic, not necessarily an expert in geomechanics or fracture stimulation.