Access valve for drill stem testing

Activating mechanism for controlling the operation of a...

Activation mechanism for differential fill floating equipment

Actuating ball

Adjustable safety valve

Annular flow control safety valve

Annulus operated test valve

Annulus pressure controlled reversing valve

Annulus pressure controlled test valve with locking annulus pres

Annulus pressure operated closure valve with improved power mand

Annulus pressure operated downhole choke and associated methods

Annulus safety apparatus

Annulus safety valve

Anti blow-out control apparatus

Apparatus and method for controlling the flow of fluids from a w

Apparatus and method for lifting a bop from a wellhead

Apparatus and method for performing a desired operation at a spe

Apparatus and method for protecting well bore

Apparatus and method for running, setting and testing a compress

Apparatus and process for drawing water from a water-bearing str