SYSTEM FOR CONTROLLING THE FLOW OF WELL FLUID

摘要

A system for controlling the flow of well fluid between a well annulus and a n internal flowbore of a tubing string, that system comprises a tubular housin g in the tubing string having a fluid flow aperture through a tubular wall thereof around sa id flowbore. A substantially coaxial tubular sleeve adjacent said housing for selectively obstructing the fluid flow area of said flow aperture; a first actuator for selectively displacing said sleeve in a first direction; and a second actuator for incrementally displacing said sleeve in a second direction wherein a fluid flow area through said aperture is changed in corresponding increments, and a force required to displace said sleeve from one flow rate increment to another increases incrementally.