Abstract: A gas operated plunger for lifting well fluids from a subterranean reservoir to the surface through a well conduit comprising: a plunger body slidably mountable within the conduit having an upper portion, a lower portion and an intermediate cylindrical portion of reduced diameter; and a sealing assembly surrounding the intermediate cylindrical portion of the plunger body. The sealing assembly may include a plurality of longitudinally divided cylindrical segments of relatively smooth cylindrical surfaces for sliding and sealing contact with the well conduit walls to provide a seal which allows the plunger to gravitate through the well conduit to the reservoir and provides sufficient sealing upon an increase in gas pressure therebelow to elevate the plunger and well fluids thereabove to the surface.