A gas-lift well system, comprising: a casing extending down a wellbore ; production tubing extending within the casing ; a gas system for introducing compressed gas into an annular space between the casing and the production tubing ; at least one gas-lift input extending from the annular space to an interior of the production tubing ; and at least one fluid flow regime modifier (132; 332; 432; 532; 632; 732; 832; 932; 1032; 1132) within the production tubing and at least partially within a fluid column of the production tubing , the at least one fluid flow regime modifier (132... 1132) configured to reduce fluid fallback and impart a turbulent flow regime to at least a portion of the fluid column, characterized in that the at least one fluid flow regime modifier (132...1132) comprises: a central rod extending along a longitudinal length of the production tubing and at least substantially centered within the production tubing ; and a plurality of fin members extending radially outward from the central rod , wherein each fin member of the plurality of fin members comprises a loop of material extending from a first axial position along the longitudinal length of the central rod to a different, second axial position along the longitudinal length of the central rod , wherein, for each fin member , the first position and the second position are located along a line parallel to a central longitudinal axis of the central rod . a casing extending down a wellbore ; production tubing extending within the casing ; a gas system for introducing compressed gas into an annular space between the casing and the production tubing ; at least one gas-lift input extending from the annular space to an interior of the production tubing ; and at least one fluid flow regime modifier (132; 332; 432; 532; 632; 732; 832; 932; 1032; 1132) within the production tubing and at least partially within a fluid column of the production tubing , the at least one fluid flow regime modifier (132... 1132) configured to reduce fluid fallback and impart a turbulent flow regime to at least a portion of the fluid column, characterized in that the at least one fluid flow regime modifier (132...1132) comprises: a central rod extending along a longitudinal length of the production tubing and at least substantially centered within the production tubing ; and a plurality of fin members extending radially outward from the central rod , wherein each fin member of the plurality of fin members comprises a loop of material extending from a first axial position along the longitudinal length of the central rod to a different, second axial position along the longitudinal length of the central rod , wherein, for each fin member , the first position and the second position are located along a line parallel to a central longitudinal axis of the central rod . a central rod extending along a longitudinal length of the production tubing and at least substantially centered within the production tubing ; and a plurality of fin members extending radially outward from the central rod , wherein each fin member of the plurality of fin members comprises a loop of material extending from a first axial position along the longitudinal length of the central rod to a different, second axial position along the longitudinal length of the central rod , wherein, for each fin member , the first position and the second position are located along a line parallel to a central longitudinal axis of the central rod . <EOS>