To remove the formation fluids now trapped in the annulus a high pressure circulating system is used. A choke manifold with an adjustable choke is used to control flow rates during the circulation. Basically heavier mud must be pumped down the drillpipe to control the formation pressure, and the fluids in the annulus circulated to surface. As the kick starts moving up the hole the choke opening is restricted to hold enough back pressure on the formation to prevent any further influx. The fluids are circulated out via the choke line, through the choke manifold out to a gas/mud separator and a flare stack (Figure 16). Once the heavier mud has reached surface the well should be dead.