A plant for treating fluid products obtained from an oil well, to produce a hydrocarbon product, comprises a series of separators at progressively lower pressures, to which the fluid products are supplied in succession. A high pressure gas phase is obtained from the separator and is supplied to a flow restrictor so as to undergo cooling through the Joule Thomson effect, and then passed to a NGL separator to produce a natural gas liquid stream and a gaseous natural gas stream. The natural gas stream is then processed chemically, using a synthesis gas production unit, and a Fischer-Tropsch synthesis unit to produce a synthetic crude oil. The synthetic crude oil is supplied to one of the separators, and the natural gas liquid stream is supplied to another of the separators; the pressure in the one separator is greater than the pressure in the other separator.