A passive multiphase separator is configured to separate gas from a two-phase fluid in a wellbore. The passive multiphase separator includes an intake tube that has an intake end, a discharge end and an interior section between the intake end and the discharge end. The interior section includes a rifled interior surface that induces rotation in fluids passing through the interior section. The passive multiphase separator further includes a head assembly connected to the discharge end of the intake tube. The head assembly includes a crossover tube extending into the interior section, one or more gas vents extending from an interior of the crossover tube to an exterior of the head assembly and a liquid discharge. The passive multiphase separator can be deployed in a variety of hydrocarbon recovery systems.