A slurry discharge device for use in a subterranean well can include a slurry flow passage extending longitudinally in the device. The slurry flow passage has flow passage sections. One flow passage section is positioned downstream of, and is laterally offset relative to, another flow passage section. Another slurry discharge device can include the slurry flow passage having multiple flow areas. One flow area is positioned in a downstream direction from, and is greater than, another flow area. A method of delivering a slurry into a subterranean well can include discharging the slurry from a tubular string through a first sidewall section of a slurry discharge device; and flowing only a returned fluid portion of the slurry through a second sidewall section of the slurry discharge device. The second sidewall section has a lateral thickness greater than a lateral thickness of the first sidewall section.