Removing carbon dioxide, ethane and heavier components from a high pressure natural gas stream, comprises: (a) partly condensing and expanding the high pressure natural gas stream to obtain a stream enriched in methane and carbon dioxide and at least one liquid stream enriched in ethane and heavier components; (b) introducing the stream enriched in methane and carbon dioxide at fractionation pressure into a fractionation column which includes several fractionation stages; (c) introducing the liquid stream(s) at fractionation pressure into the column at a level which is below the level of introducing the stream enriched in methane and carbon dioxide; (d) removing from the fractionation column, below the level of introducing the liquid stream(s), at least one fluid stream, heating the fluid stream(s) to obtain reboiling stream(s), and introducing the reboiling stream(s) into the fractionation column; (e) removing from the bottom of the column a liquid stream enriched in carbon dioxide, ethane and heavier components; and (f) removing from the top of the column a gaseous overhead stream enriched in methane. The process further comprises: (g) cooling the gaseous overhead stream at fractionation pressure to obtain a two-phase fluid, separating the two-phase fluid into a cooled gaseous overhead stream and a liquid stream, and introducing the liquid stream as a first reflux stream into the column at a level above the level of introducing the stream enriched in methane and carbon dioxide; and (h) expanding the cooled gaseous overhead stream to obtain a two-phase fluid at low pressure, separating the two-phase fluid into a gaseous product stream and a liquid stream, and introducing the liquid stream as a second reflux stream into the column at a level above the level of introducing the first reflux stream.    USE -   Used for removing carbon dioxide, ethane and heavier components from a natural gas.    ADVANTAGE -   Natural gas has carbon dioxide content reduced by cooling the gaseous overhead to condense enough ethane to dissolve a large amount of carbon dioxide, which is returned in the first reflux stream, overcoming the freezing of carbon dioxide in the turbine expander.