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Abstract The adage that "the easy oil is gone" underscores the need for continuous advancements in drilling technologies. Among these innovations is slim hole drilling, which has gained relevance across various applications, including casing drilling and mineral exploration. The objective of this paper is to identify and assess operational strategies for safely detecting and circulating gas influxes from a borehole to support the development of effective and reliable well-control procedures tailored to slim hole environments. The scenario in question involves a mineral exploration rig equipped with slick 70 mm (2¾ in.) OD drill rods drilling a 76 mm (3 in.) ID borehole to a depth of 1,600 m. Transient flow simulation tools were employed to evaluate the hydraulics and well-control phenomena associated with such a slim-hole configuration. Influx scenarios included fractured formations combined with lost circulation and the risks of encountering small high-pressure cavities in impermeable rock. Sensitivity analyses were performed to evaluate the effects of varying kick size and intensity. The reduced annular clearance between drill string and borehole introduces substantial differences from conventional drilling hydraulics and well-control principles. Simulations using conventional oilfield drilling fluids revealed that non-Newtonian fluids led to excessive equivalent circulating densities (ECD), making the use of solids-free Newtonian water-based fluids essential. Rotary speeds typical of slim-hole mineral exploration operations, up to 300 rpm, were shown to contribute an additional 0.36 SG (3 ppg) to ECD. Kick simulations revealed that standard well-control practices, such as immediate shut-in followed by the Driller's Method for circulating out a kick, were not optimal in slim-hole conditions. Depending on annular geometry and influx characteristics, a dynamic kill approach offered safer and more efficient control. The scenarios are based on a mineral exploration rig equipped with a 150 mm (6 in.) ID annular blowout preventer venting into a mud gas separator. Despite its limitations, transient simulations demonstrated that such minimal equipment is capable of managing the envisaged well control events. The findings supported the development of tailored well-control procedures, improving operational safety and reliability in such a complex environment. The use of transient flow simulations to evaluate well-control operations and equipment for slim-hole wells is described. The examples highlight how local geology dictates the well-control measures that need to be implemented. The findings demonstrate how modeling can guide equipment selection, procedure development, and training programs, enhancing preparedness for slim-hole drilling operations.