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1. (WO1999009291) METHOD AND APPARATUS FOR MOVING A PISTON

Pub. No.:    WO/1999/009291    International Application No.:    PCT/US1998/016665
Publication Date: Fri Feb 26 00:59:59 CET 1999 International Filing Date: Thu Aug 13 01:59:59 CEST 1998
IPC: E21B 4/18
E21B 23/04
Applicants: GAZEWOOD, Michael, J.
Inventors: GAZEWOOD, Michael, J.
Title: METHOD AND APPARATUS FOR MOVING A PISTON
Abstract:
An apparatus and method for creating a pulling force on a bottom hole assembly is disclosed. The apparatus comprises a housing (42), a piston (70) having a first section (72) and a second section (78), and a venturi member (110), operatively associated with the piston (70). The housing is attached to a work string and the piston (70) is attached to a bottom hole assembly. The first and second sections of the piston and housing form a first chamber (102) and a second chamber (103). The venturi member (111) contains a first passageway (74) for communicating the zone of low pressure created by the venturi member (111) with the first chamber (102); and a second passageway (74) for communicating the inner diameter of the venturi means (111) with the second chamber (103). The venturi member (111) comprises a nozzle (120) operatively associated with the piston (70); a mixing tuber (93A), formed on the inner diameter of the piston; and, a diffuser section (93B) adjoining the mixing tube.