Choke valves are severe service valves which are designed specifically for oil and gas wellhead applications, both in a surface and subsurface context. They are used for controlling the flow on production, re-injection and subsurface wellheads.
Choke valves allow fluid flow through a very small opening, designed to kill the reservoir pressure while regulating the well production. The reservoir fluids can contain sand particles. Hence the choke valves are usually designed to handle an erosive service.