Patent ID: 6283202
Filing Date: 2001-09-04
Classification: E21B

Abstract:
An apparatus for dispensing a chemical additive element, such as a soap stick, into a wellbore comprising:an elongated tubular magazine member for holding at least one soap stick;a first fitting operably connected to said magazine member for mounting said apparatus on a wellhead for placing said magazine member in communication with a tubing extending from said wellhead into a wellbore;a soap stick retention valve disposed between said magazine member and said first fitting and including a valve closure member operable, in a closed position, to retain said soap stick in said magazine member, said retention valve forming a first chamber between said closure member and said first fitting;a second fitting forming a second chamber, generally above said soap stick and in communication with said magazine member;a bypass conduit connected to said apparatus to provide fluid flow between said fittings and around said closure member of said retention valve to substantially equalize fluid pressure in said chambers; anda driver valve operable to be in a closed position to prevent fluid flow through said bypass conduit to said second chamber and responsive to a signal to move to an open position to communicate pressure fluid to said second chamber to substantially equalize pressures in said chambers to allow said soap stick to move said closure member of said retention valve to an open position to dispense said soap stick into said wellbore.