Abstract: An apparatus and methods are disclosed for using optical sensors to determine the position of a movable flow control element in a well control tool. A housing has a movable element disposed within such that the element movement controls the flow through the tool. An optical sensing system senses the movement of the element. Optical sensors are employed that use Bragg grating reflections, time domain reflectometry, and line scanning techniques to determine the element position. A surface or downhole processor is used to interpret the sensor signals.

Abstract: An expendable plug is shown for use in a well bore tool for controlling the flow of well bore fluids from a production zone to the well surface. The plug is located within a tubular housing which is made up in a well tubing string having an internal bore with a predetermined minimum internal diameter. The plug initially closes off the internal bore of the tubing string at a selected location. An actuator is triggered by an appropriate signal to expend the plug of expendable material, and to remove the plug from the internal bore of the tubing string, whereby fluids in the surrounding earthen formation are allowed to flow up the tubing string to the well surface.