Abstract: A system for controlling fluid flow from multiple isolated producing zones in a well is provided. Components of the system are placeable in and retrievable from bottom entry side pocket mandrel sections permanently installed in a production tubing string in the well. These components include retrievable isolation valve modules. Control signals for modules are developed either downhole or at the surface and modules may be placed or retrieved through the production tubing without pulling the production tubing from the well. In high flow rate applications the sliding sleeve flow control valve of the present invention provides a variable aperture valve having a fully open cross sectional area equal to that of the production tubing, thereby achieving a minimal pressure drop across the valve.

Abstract: A system for controlling fluid flow from multiple isolated producing zones in a well is provided. Components of the system are placeable in and retrievable from bottom entry side pocket mandrel sections permanently installed in a production tubing string in the well. These components provided are sensor modules, isolation valve modules, power modules, control modules, hydraulic pump control modules and packer modules which are carried by the production tubing string. Control signals for modules are developed either downhole or at the surface and modules may be placed or retrieved through the production tubing without pulling the production tubing from the well.

Abstract: In accordance with an illustrative embodiment of the present invention, a surface controlled subsurface safety valve system includes a tubing retrievable safety valve having a valve element that is opened and held open in response to the pressure of a control fluid in a control line and automatically closed when control pressure is reduced, and means for equalizing the pressure of fluids above and below said valve element to aid in reopening the same after closure, including a wireline retrievable equalizing valve removably installed in the pocket of a side pocket mandrel that is connected in the tubing above said safety valve, said equalizing valve being arranged to be opened and closed in response to changes in the pressure of said control fluid. A uniquely constructed side pocket mandrel also is disclosed.