Influx of a shallow gas kick during offshore top-hole drilling without a riser can result in critical well-control problems. An existing gas kick simulator was modified to provide a tool for planning corrective actions before and during drilling operations. Simulations showed threshold levels for uncontrolled blowouts as a function of gas-zone permeability and gas pressure when using a 9 5/8-in. pilot hole and a 17 1/2-in. hole. Dynamic circulation control of a shallow gas kick as a function of time after penetration of the gas zone demonstrates the advantages of a pilot hole. The simulator has been a valuable tool for safety analysis and drilling-operations planning.