When upward-flowing water jet impinges on an interface with an immiscible layer of lighter oil above it. the jet momentum lifts the interface and forms a cavity. Below a threshold based on Richardson number (Ri) and Reynolds number (Re), no droplets form. Above this threshold, oil drops are formed two Richardson number-dependent mechanisms. At high Richardson number, an oil lip created at the edge of the cavity detaches to form oil droplets in the looter below. At lower Richardson number, the water cavity becomes unstable and alternately collapses and reforms. As the collapsing cavity impacts the interface, it drags down fingers of the upper oil layer, which break into oil droplets. This article contains extensive droplet size distributions for varying Richardson number and Reynolds number and discusses the effects of varying viscosity ratio (eta) and Morton number (Mo). Droplet sizes exhibit polydisperse log-normal distributions with mode diameters ranging from 0.6 to 1.5 mm. Characteristic diameters decrease primarily with increasing Re-3/Ri, and to a lesser extent with decreasing viscosity ratio. Droplet distributions resulting front the lip pinch-off mechanism have a larger characteristic diameter than those formed by the cavity collapse mechanism.