The present disclosure provides a gullet mandrel for fluid flow optimization in a wellbore. The gullet mandrel may be coupled to a downhole valve, such that a tubing string in a wellbore will have a plurality of valves coupled to a plurality of mandrels. Each gullet mandrel may have a valve recess and one or more gullets (or grooves) located in an exterior portion of the mandrel body. The gullets may have a wide variety of configurations, and may be formed in a portion, a majority, or substantially all of the mandrel. The gullets may direct movement of fluid exterior to the tubing string and help force fluid into a laminar or linear flow pattern and prevent the formation of slug flows and/or lessen the problems encountered by slug flows. The disclosed gullet mandrel may be used in any fluid injection or production operation, such as gas-lift operations.